TECHNICAL FIELD
The disclosure, in various embodiments, relates generally to the field of microelectronic device design and fabrication. More specifically, the disclosure relates to methods of forming microelectronic devices, and to related microelectronic devices, memory devices, and electronic systems.
BACKGROUND
Microelectronic device designers often desire to increase the level of integration or density of features within a microelectronic device by reducing the dimensions of the individual features and by reducing the separation distance between neighboring features. In addition, microelectronic device designers often desire to design architectures that are not only compact, but offer performance advantages, as well as simplified, easier and less expensive to fabricate designs.
One example of a microelectronic device is a memory device. Memory devices are generally provided as internal integrated circuits in computers or other electronic devices. There are many types of memory devices including, but not limited to, non-volatile memory (NVM) devices, such as flash memory devices (e.g., NAND flash memory devices). One way of increasing memory density in non-volatile memory devices is to utilize vertical memory array (also referred to as a “three-dimensional (3D) memory array”) architectures. A conventional vertical memory array includes vertical memory strings extending through openings in one or more decks (e.g., stack structures) including structures of conductive structures and dielectric materials. Each vertical memory string may include at least one select device coupled in series to a serial combination of vertically stacked memory cells. Such a configuration permits a greater number of switching devices (e.g., transistors) to be located in a unit of die area (i.e., length and width of active surface consumed) by building the array upwards (e.g., vertically) on a die, as compared to structures with conventional planar (e.g., two-dimensional) arrangements of transistors.
Vertical memory array architectures generally include electrical connections between the conductive material of the tiers of the stack structure(s) of the memory device and control logic devices (e.g., string drivers) so that the memory cells of the vertical memory array can be uniquely selected for writing, reading, or erasing operations. One method of forming such an electrical connection includes forming so-called “staircase” (or “stair step”) structures at edges (e.g., horizontal ends) of the tiers of the stack structure(s) of the memory device. The staircase structure includes individual “steps” defining contact regions for the conductive material of the tiers, upon which conductive contact structures can be positioned to provide electrical access to the conductive material. In turn, conductive routing structures can be employed to couple the conductive contact structures to the control logic devices. Unfortunately, as feature packing densities have increased and margins for formation errors have decreased, conventional fabrication methods and resulting structural configurations have resulted in undesirable defects that can diminish desired memory device performance, reliability, and durability.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing out and distinctly claiming embodiments of the present disclosure, the advantages of embodiments of the disclosure may be more readily ascertained from the following description of embodiments of the disclosure when read in conjunction with the accompanying drawings in which:
FIG. 1A is a simplified, partial perspective view of a microelectronic device structure at a processing stage of a method forming a microelectronic device, in accordance with embodiments of the disclosure. FIG. 1B is a simplified, longitudinal cross-sectional view of a portion A (identified with dashed lines in FIG. 1A) of the microelectronic device structure at the processing stage of FIG. 1A. FIG. 1C is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIGS. 1A and 1B about a dashed line B-B shown in FIG. 1B.
FIG. 2A is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure shown in FIGS. 1A through 1C at another processing stage of the method forming the microelectronic device following the processing stage of FIGS. 1A through 1C. FIG. 2B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIG. 2A about the dashed line B-B shown in FIG. 2A.
FIG. 3A is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure shown in FIGS. 1A through 1C at another processing stage of the method forming the microelectronic device following the processing stage of FIGS. 2A and 2B. FIG. 3B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIG. 3A about the dashed line B-B shown in FIG. 3A.
FIG. 4A is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure shown in FIGS. 1A through 1C at another processing stage of the method forming the microelectronic device following the processing stage of FIGS. 3A and 3B. FIG. 4B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIG. 4A about the dashed line B-B shown in FIG. 4A.
FIGS. 5A-5C illustrate simplified, enlarged longitudinal cross-sectional views of one of the dielectric structure of the microelectronic device structure at the processing stage of FIGS. 4A and 4B, in accordance with embodiments of the disclosure.
FIG. 6A is a simplified, partial perspective view of a microelectronic device structure shown in FIGS. 1A through 1C at another processing stage of the method forming the microelectronic device following the processing stage of FIGS. 4A and 4B. FIG. 6B is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure shown at the processing stage of FIG. 6A. FIG. 6C is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIGS. 6A and 6B about a dashed line B-B shown in FIG. 6B.
FIG. 7A is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure shown in FIGS. 1A through 1C at another processing stage of the method forming the microelectronic device following the processing stage of FIGS. 6A and 6B. FIG. 7B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIG. 7A about the dashed line B-B shown in FIG. 7A.
FIG. 8A is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure shown in FIGS. 1A through 1C at another processing stage of the method forming the microelectronic device following the processing stage of FIGS. 7A and 7B. FIG. 8B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIG. 8A about the dashed line B-B shown in FIG. 8A.
FIG. 9 is a simplified partial cutaway perspective view of a microelectronic device, in accordance with embodiments of the disclosure.
FIG. 10 is a schematic block diagram of an electronic system in accordance with one or more embodiments of the disclosure.
DETAILED DESCRIPTION
The following description provides specific details, such as material compositions, shapes, and sizes, in order to provide a thorough description of embodiments of the disclosure. However, a person of ordinary skill in the art would understand that the embodiments of the disclosure may be practiced without employing these specific details. Indeed, the embodiments of the disclosure may be practiced in conjunction with conventional microelectronic device fabrication techniques employed in the industry. In addition, the description provided below does not form a complete process flow for manufacturing a microelectronic device (e.g., a memory device). The structures described below do not form a complete microelectronic device. Only those process acts and structures necessary to understand the embodiments of the disclosure are described in detail below. Additional acts to form a complete microelectronic device from the structures may be performed by conventional fabrication techniques.
Drawings presented herein are for illustrative purposes only, and are not meant to be actual views of any particular material, component, structure, device, or system. Variations from the shapes depicted in the drawings as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein are not to be construed as being limited to the particular shapes or regions as illustrated, but include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as box-shaped may have rough and/or nonlinear features, and a region illustrated or described as round may include some rough and/or linear features. Moreover, sharp angles that are illustrated may be rounded, and vice versa. Thus, the regions illustrated in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shape of a region and do not limit the scope of the present claims. The drawings are not necessarily to scale. Additionally, elements common between figures may retain the same numerical designation.
As used herein, a “memory device” means and includes microelectronic devices exhibiting memory functionality, but not necessary limited to memory functionality. Stated another way, and by way of non-limiting example only, the term “memory device” includes not only conventional memory (e.g., conventional non-volatile memory; conventional volatile memory), but also includes an application specific integrated circuit (ASIC) (e.g., a system on a chip (SoC)), a microelectronic device combining logic and memory, and a graphics processing unit (GPU) incorporating memory.
As used herein, the terms “configured” and “configuration” refers to a size, a shape, a material composition, a material distribution, orientation, and arrangement of at least one feature (e.g., one or more of at least one structure, at least one material, at least one region, at least one device) facilitating use of the at least one feature in a pre-determined way.
As used herein, the term “substantially” in reference to a given parameter means and includes to a degree that one skilled in the art would understand that the given parameter, property, or condition is met with a small degree of variance, such as within acceptable manufacturing tolerances. By way of example, depending on the particular parameter, property, or condition that is substantially met, the parameter, property, or condition may be at least 90.0 percent met, at least 95.0 percent met, at least 99.0 percent met, at least 99.9 percent met, or even 100.0 percent met.
As used herein, “about” or “approximately” in reference to a numerical value for a particular parameter is inclusive of the numerical value and a degree of variance from the numerical value that one of ordinary skill in the art would understand is within acceptable tolerances for the particular parameter. For example, “about” or “approximately” in reference to a numerical value may include additional numerical values within a range of from 90.0 percent to 110.0 percent of the numerical value, such as within a range of from 95.0 percent to 105.0 percent of the numerical value, within a range of from 97.5 percent to 102.5 percent of the numerical value, within a range of from 99.0 percent to 101.0 percent of the numerical value, within a range of from 99.5 percent to 100.5 percent of the numerical value, or within a range of from 99.9 percent to 100.1 percent of the numerical value.
As used herein, relational terms, such as “beneath,” “below,” “lower,” “bottom,” “above,” “upper,” “top,” “front,” “rear,” “left,” “right,” and the like, may be used for ease of description to describe one element's or feature's relationship to another element(s) or feature(s) as illustrated in the drawings. Unless otherwise specified, the spatially relative terms are intended to encompass different orientations of the materials in addition to the orientation depicted in the figures. For example, if materials in the figures are inverted, elements described as “below” or “beneath” or “under” or “on bottom of” other elements or features would then be oriented “above” or “on top of” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below, depending on the context in which the term is used, which will be evident to one of ordinary skill in the art. The materials may be otherwise oriented (e.g., rotated 90 degrees, inverted, flipped) and the spatially relative descriptors used herein interpreted accordingly.
As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
As used herein, the term “and/or” means and includes any and all combinations of one or more of the associated listed items.
As used herein, the terms “vertical,” “longitudinal,” “horizontal,” and “lateral” are in reference to a major plane of a structure and are not necessarily defined by earth's gravitational field. A “horizontal” or “lateral” direction is a direction that is substantially parallel to the major plane of the structure, while a “vertical” or “longitudinal” direction is a direction that is substantially perpendicular to the major plane of the structure. The major plane of the structure is defined by a surface of the structure having a relatively large area compared to other surfaces of the structure. With reference to the drawings, a “horizontal” or “lateral” direction may be perpendicular to an indicated “Z” axis, and may be parallel to an indicated “X” axis and/or parallel to an indicated “Y” axis; and a “vertical” or “longitudinal” direction may be parallel to an indicated “Z” axis, may be perpendicular to an indicated “X” axis, and may be perpendicular to an indicated “Y” axis.
As used herein, “conductive material” means and includes electrically conductive material such as one or more of a metal (e.g., tungsten (W), titanium (Ti), molybdenum (Mo), niobium (Nb), vanadium (V), hafnium (Hf), tantalum (Ta), chromium (Cr), zirconium (Zr), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pa), platinum (Pt), copper (Cu), silver (Ag), gold (Au), aluminum (Al)), an alloy (e.g., a Co-based alloy, an Fe-based alloy, an Ni-based alloy, an Fe- and Ni-based alloy, a Co- and Ni-based alloy, an Fe- and Co-based alloy, a Co- and Ni- and Fe-based alloy, an Al-based alloy, a Cu-based alloy, a magnesium (Mg)-based alloy, a Ti-based alloy, a steel, a low-carbon steel, a stainless steel), a conductive metal-containing material (e.g., a conductive metal nitride, a conductive metal silicide, a conductive metal carbide, a conductive metal oxide), and a conductively-doped semiconductor material (e.g., conductively-doped polysilicon, conductively-doped germanium (Ge), conductively-doped silicon germanium (SiGe)). In addition, a “conductive structure” means and includes a structure formed of and including conductive material.
As used herein, “insulative material” means and includes electrically insulative material, such one or more of at least one dielectric oxide material (e.g., one or more of a silicon oxide (SiOx), phosphosilicate glass, borosilicate glass, borophosphosilicate glass, fluorosilicate glass, an aluminum oxide (AlOx), a hafnium oxide (HfOx), a niobium oxide (NbO−x−), a titanium oxide (TiOx), a zirconium oxide (ZrOx), a tantalum oxide (TaOx), and a magnesium oxide (MgOx)), at least one dielectric nitride material (e.g., a silicon nitride (SiNy)), at least one dielectric oxynitride material (e.g., a silicon oxynitride (SiOxNy)), at least one dielectric oxycarbide material (e.g., silicon oxycarbide (SiOxCy)), at least one hydrogenated dielectric oxycarbide material (e.g., hydrogenated silicon oxycarbide (SiCxOyHz)), and at least one dielectric carboxynitride material (e.g., a silicon carboxynitride (SiOxCzNy)). Formulae including one or more of “x,” “y,” and “z” herein (e.g., SiOx, AlOx, HfOx, NbO−x, TiOx, SiNy, SiOxNy, SiOxCy, SiCxOyHz, SiOxCzNy) represent a material that contains an average ratio of “x” atoms of one element, “y” atoms of another element, and “z” atoms of an additional element (if any) for every one atom of another element (e.g., Si, Al, Hf, Nb, Ti). As the formulae are representative of relative atomic ratios and not strict chemical structure, an insulative material may comprise one or more stoichiometric compounds and/or one or more non-stoichiometric compounds, and values of “x,” “y,” and “z” (if any) may be integers or may be non-integers. As used herein, the term “non-stoichiometric compound” means and includes a chemical compound with an elemental composition that cannot be represented by a ratio of well-defined natural numbers and is in violation of the law of definite proportions. In addition, an “insulative structure” means and includes a structure formed of and including insulative material.
As used herein, the term “homogeneous” means relative amounts of elements included in a feature (e.g., a material, a structure) do not vary throughout different portions (e.g., different horizontal portions, different vertical portions) of the feature. Conversely, as used herein, the term “heterogeneous” means relative amounts of elements included in a feature (e.g., a material, a structure) vary throughout different portions of the feature. If a feature is heterogeneous, amounts of one or more elements included in the feature may vary stepwise (e.g., change abruptly), or may vary continuously (e.g., change progressively, such as linearly, parabolically) throughout different portions of the feature. The feature may, for example, be formed of and include a stack of at least two different materials.
Unless the context indicates otherwise, the materials described herein may be formed by any suitable technique including, but not limited to, spin coating, blanket coating, chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), atomic layer deposition (ALD), plasma enhanced ALD (PEALD), physical vapor deposition (PVD) (e.g., sputtering), or epitaxial growth. Depending on the specific material to be formed, the technique for depositing or growing the material may be selected by a person of ordinary skill in the art. In addition, unless the context indicates otherwise, removal of materials described herein may be accomplished by any suitable technique including, but not limited to, etching (e.g., dry etching, wet etching, vapor etching), ion milling, abrasive planarization (e.g., chemical-mechanical planarization (CMP)), or other known methods.
FIGS. 1A through 8B are various views (described in further detail below) illustrating a microelectronic device structure at different processing stages of a method of forming a microelectronic device (e.g., a memory device, such as a 3D NAND Flash memory device), in accordance with embodiments of the disclosure. With the description provided below, it will be readily apparent to one of ordinary skill in the art that the methods described herein may be used for forming various devices. In other words, the methods of the disclosure may be used whenever it is desired to form a microelectronic device.
FIG. 1A depicts a simplified, partial perspective view of a microelectronic device structure 100. As shown in FIG. 1A, the microelectronic device structure 100 may be formed to include a preliminary stack structure 102 including a vertically alternating (e.g., in a Z-direction) sequence of insulative material 104 and sacrificial material 106 arranged in tiers 108. Each of the tiers 108 of the preliminary stack structure 102 may individually include the sacrificial material 106 vertically neighboring (e.g., directly vertically adjacent) the insulative material 104. FIG. 1B is a simplified, longitudinal cross-sectional view of a portion A (identified with a dashed box in FIG. 1A) of the microelectronic device structure 100 at the processing stage depicted in FIG. 1A. FIG. 1C is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure at the processing stage of FIGS. 1A and 1B about a dashed line B-B shown in FIG. 1B.
The insulative material 104 of each of the tiers 108 of the preliminary stack structure 102 may be formed of and include at least one dielectric material, such one or more of at least one dielectric oxide material (e.g., one or more of SiOx, phosphosilicate glass, borosilicate glass, borophosphosilicate glass, fluorosilicate glass, AlOx, HfOx, NbO−x−, TiOx, ZrOx, TaOx, and MgOx), at least one dielectric nitride material (e.g., SiNy), at least one dielectric oxynitride material (e.g., SiOxNy), and at least one dielectric carboxynitride material (e.g., SiOxCzNy). In some embodiments, the insulative material 104 of each of the tiers 108 of the preliminary stack structure 102 is formed of and includes a dielectric oxide material, such as SiOx (e.g., SiO2). The insulative material 104 of each of the tiers 108 may be substantially homogeneous, or the insulative material 104 of one or more (e.g., each) of the tiers 108 may be heterogeneous.
The sacrificial material 106 of each of the tiers 108 of the preliminary stack structure 102 may be formed of and include at least one material (e.g., at least one insulative material) that may be selectively removed relative to the insulative material 104. The sacrificial material 106 may be selectively etchable relative to the insulative material 104 during common (e.g., collective, mutual) exposure to a first etchant; and the insulative material 104 may be selectively etchable to the sacrificial material 106 during common exposure to a second, different etchant. As used herein, a material is “selectively etchable” relative to another material if the material exhibits an etch rate that is at least about five times (5×) greater than the etch rate of another material, such as about ten times (10×) greater, about twenty times (20×) greater, or about forty times (40×) greater. By way of non-limiting example, depending on the material composition of the insulative material 104, the sacrificial material 106 may be formed of and include one or more of at least one dielectric oxide material (e.g., one or more of SiOx, phosphosilicate glass, borosilicate glass, borophosphosilicate glass, fluorosilicate glass, AlOx, HfOx, NbO−x−, TiOx, ZrOx, TaOx, and a MgOx), at least one dielectric nitride material (e.g., SiNy), at least one dielectric oxynitride material (e.g., SiOxNy), at least one dielectric oxycarbide material (e.g., SiOxCy), at least one hydrogenated dielectric oxycarbide material (e.g., SiCxOyHz), at least one dielectric carboxynitride material (e.g., SiOxCzNy), and at least one semiconductive material (e.g., polycrystalline silicon). In some embodiments, the sacrificial material 106 of each of the tiers 108 of the preliminary stack structure 102 is formed of and includes a dielectric nitride material, such as SiNy (e.g., Si3N4). The sacrificial material 106 may, for example, be selectively etchable relative to the insulative material 104 during common exposure to a wet etchant comprising phosphoric acid (H3PO4).
The preliminary stack structure 102 may be formed to include any desired number of the tiers 108. By way of non-limiting example, the preliminary stack structure 102 may be formed to include greater than or equal to sixteen (16) of the tiers 108, such as greater than or equal to thirty-two (32) of the tiers 108, greater than or equal to sixty-four (64) of the tiers 108, greater than or equal to one hundred and twenty-eight (128) of the tiers 108, or greater than or equal to two hundred and fifty-six (256) of the tiers 108.
As shown in FIG. 1A, the preliminary stack structure 102 may include stadium structures 110 formed therein. The stadium structures 110 may be distributed throughout the preliminary stack structure 102. As shown in FIG. 1A, the preliminary stack structure 102 may include rows of the stadium structures 110 extending in parallel in a X-direction, and columns of the stadium structures 110 extending in a Y-direction orthogonal to the X-direction. The rows of the stadium structures 110 may individually include some of the stadium structures 110 at least partially (e.g., substantially) aligned with one another in the Y-direction. The columns of the of the stadium structures 110 may individually include other of the stadium structures 110 at least partially (e.g., substantially) aligned with one another in the X-direction. Different rows of the stadium structures 110 may be positioned within different horizontal areas of the preliminary stack structure 102 to be formed into different blocks of a stack structure to be formed from the preliminary stack structure 102, as described in further detail below. In FIG. 1A, for clarity and ease of understanding the drawings and associated description, portions of the preliminary stack structure 102 are depicted as transparent to more clearly show some of the stadium structures 110 distributed within the preliminary stack structure 102.
Still referring to FIG. 1A, at least some (e.g., each) of the stadium structures 110 within an individual row of the stadium structures 110 may be positioned at different vertical elevations in the Z-direction than one another. For example, as depicted in FIG. 1A, an individual row of the stadium structures 110 may include a first stadium structure 110A, a second stadium structure 110B at a relatively lower vertical position (e.g., in the Z-direction) within the preliminary stack structure 102 than the first stadium structure 110A, a third stadium structure 110C at a relatively lower vertical position within the preliminary stack structure 102 than the second stadium structure 110B, and a fourth stadium structure 110D at a relatively lower vertical position within the block 130 than the third stadium structure 110C. In addition, within an individual row of the stadium structures 110, horizontally neighboring (e.g., in the X-direction) stadium structures 110 may be substantially uniformly (e.g., equally, evenly) horizontally spaced apart from one another. In additional embodiments, one or more rows of the stadium structures 110 may individually include a different quantity of stadium structures 110 and/or a different distribution of stadium structures 110 than that depicted in FIG. 1A. For example, an individual row of the stadium structures 110 may include greater than four (4) of the stadium structures 110 (e.g., greater than or equal to five (5) of the stadium structures 110, greater than or equal to ten (10) of the stadium structures 110, greater than or equal to twenty-five (25) of the stadium structures 110, greater than or equal to fifty (50) of stadium structures 110), or less than four (4) of the stadium structures 110 (e.g., less than or equal to three (3) of the stadium structures 110, less than or equal to two (2) of the stadium structures 110, only one (1) of the stadium structures 110). As another example, within an individual row of the stadium structures 110, at least some horizontally neighboring stadium structures 110 may be at least partially non-uniformly (e.g., non-equally, non-evenly) horizontally spaced, such that at least one of the stadium structures 110 of the row is separated from at least two other of the stadium structures 110 of the row horizontally neighboring the at least one stadium structures 110 by different (e.g., non-equal) distances. As an additional non-limiting example, within an individual row of the stadium structures 110, vertical positions (e.g., in the Z-direction) of the stadium structures 110 may vary in a different manner (e.g., may alternate between relatively deeper and relatively shallower vertical positions) than that depicted in FIG. 1A.
Each stadium structure 110 may include opposing staircase structures 112, and a central region 114 horizontally interposed between (e.g., in the X-direction) the opposing staircase structures 112. The opposing staircase structures 112 of each stadium structure 110 may include a forward staircase structure 112A and a reverse staircase structure 112B. A phantom line extending from a top of the forward staircase structure 112A to a bottom of the forward staircase structure 112A may have a positive slope, and another phantom line extending from a top of the reverse staircase structure 112B to a bottom of the reverse staircase structure 112B may have a negative slope. In additional embodiments, one or more of the stadium structures 110 may individually exhibit a different configuration than that depicted in FIG. 1A. As a non-limiting example, at least one stadium structure 110 may be modified to include a forward staircase structure 112A but not a reverse staircase structure 112B (e.g., the reverse staircase structure 112B may be absent), or at least one stadium structure 110 may be modified to include a reverse staircase structure 112B but not a forward staircase structure 112A (e.g., the forward staircase structure 112A may be absent). In such embodiments, the central region 114 horizontally neighbors a bottom of the forward staircase structure 112A (e.g., if the reverse staircase structure 112B is absent), or the central region 114 horizontally neighbors a bottom of the reverse staircase structure 112B (e.g., if the forward staircase structure 112A is absent).
The opposing staircase structures 112 (e.g., the forward staircase structure 112A and the reverse staircase structure 112B) of an individual stadium structure 110 each include steps 116 defined by edges (e.g., horizontal ends) of the tiers 108 of the preliminary stack structure 102. For the opposing staircase structures 112 of an individual stadium structure 110, each step 116 of the forward staircase structure 112A may have a counterpart step 116 within the reverse staircase structure 112B having substantially the same geometric configuration (e.g., shape, dimensions), vertical position (e.g., in the Z-direction), and horizontal distance (e.g., in the X-direction) from a horizontal center (e.g., in the X-direction) of the central region 114 of the stadium structure 110. In additional embodiments, at least one step 116 of the forward staircase structure 112A does not have a counterpart step 116 within the reverse staircase structure 112B having substantially the same geometric configuration (e.g., shape, dimensions), vertical position (e.g., in the Z-direction), and/or horizontal distance (e.g., in the X-direction) from horizontal center (e.g., in the X-direction) of the central region 114 of the stadium structure 110; and/or at least one step 116 of the reverse staircase structure 112B does not have a counterpart step 116 within the forward staircase structure 112A having substantially the same geometric configuration (e.g., shape, dimensions), vertical position (e.g., in the Z-direction), and/or horizontal distance (e.g., in the X-direction) from horizontal center (e.g., in the X-direction) of the central region 114 of the stadium structure 110.
Each of the stadium structures 110 of the preliminary stack structure 102 may individually include a desired quantity of steps 116. Each of the stadium structures 110 may include substantially the same quantity of steps 116 as each other of the stadium structures 110, or at least one of the stadium structures 110 may include a different quantity of steps 116 than at least one other of the stadium structures 110. In some embodiments, at least one of the stadium structures 110 includes a different (e.g., greater, lower) quantity of steps 116 than at least one other of the stadium structures 110. As shown in FIG. 1A, in some embodiments, the steps 116 of each of the stadium structures 110 are arranged in order, such that steps 116 directly horizontally adjacent (e.g., in the X-direction) one another correspond to tiers 108 of the preliminary stack structure 102 directly vertically adjacent (e.g., in the Z-direction) one another. In additional embodiments, the steps 116 of at least one of the stadium structures 110 are arranged out of order, such that at least some steps 116 of the stadium structure 110 directly horizontally adjacent (e.g., in the X-direction) one another correspond to tiers 108 of preliminary stack structure 102 not directly vertically adjacent (e.g., in the Z-direction) one another.
With continued reference to FIG. 1A, for an individual stadium structure 110, the central region 114 thereof may horizontally intervene (e.g., in the X-direction) between and separate the forward staircase structure 112A thereof from the reverse staircase structure 112B thereof. The central region 114 may horizontally neighbor a vertically lowermost step 116 of the forward staircase structure 112A, and may also horizontally neighbor a vertically lowermost step 116 of the reverse staircase structure 112B. The central region 114 of an individual stadium structure 110 may have desired horizontal dimensions. In addition, the central region 114 of each of the stadium structures 110 may have substantially the same horizontal dimensions as the central region 114 of each other of the stadium structures 110, or the central region 114 of at least one of the stadium structures 110 may have different horizontal dimensions than the central region 114 of at least one other of the stadium structures 110.
Still referring to FIG. 1A, each stadium structure 110 (including the forward staircase structure 112A, the reverse staircase structure 112B, and the central region 114 thereof) within the preliminary stack structure 102 may individually partially define boundaries (e.g., horizontal boundaries, vertical boundaries) of a trench 118 vertically extending (e.g., in the Z-direction) through the preliminary stack structure 102. The portions of the preliminary stack structure 102 horizontally neighboring an individual stadium structure 110 may also partially define the boundaries of the trench 118 associated with the stadium structure 110. The trench 118 may vertically extend through tiers 108 of the preliminary stack structure 102 defining the forward staircase structure 112A and the reverse staircase structure 112B of the stadium structure 110; or may also vertically extend through additional tiers 108 of the preliminary stack structure 102 not defining the forward staircase structure 112A and the reverse staircase structure 112B of the stadium structure 110, such as additional tiers 108 of the preliminary stack structure 102 vertically overlying the stadium structure 110. Edges of the additional tiers 108 of the preliminary stack structure 102 may, for example, define one or more additional stadium structures vertically overlying and horizontally offset from the stadium structure 110. The trench 118 may subsequently be filled with one or more dielectric materials, as described in further detail below.
As previously described, FIG. 1B is a simplified, longitudinal cross-sectional view of portion A (identified with a dashed box in FIG. 1A) of the microelectronic device structure 100 at the processing stage depicted in FIG. 1A. The portion A encompasses the first stadium structure 110A of an individual row of the stadium structures 110 within the preliminary stack structure 102 (FIG. 1A). The portion A also encompasses regions of the preliminary stack structure 102 horizontally neighboring the first stadium structure 110A in the X-direction and the Y-direction. While additional features (e.g., structures, materials) of the microelectronic device structure 100 are described hereinbelow with reference to the portion A of the microelectronic device structure 100, such additional features may also be formed and included in additional portions of the microelectronic device structure 100, including additional portions encompassing additional stadium structures 110 of the preliminary stack structure 102 (FIG. 1A) and additional regions of the preliminary stack structure 102 having boundaries defined by the additional stadium structures 110.
In addition, as also previously described, FIG. 1C is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure 100 at the processing stage of FIGS. 1A and 1B about a dashed line B-B shown in FIG. 1B. As shown in FIG. 1C, the insulative material 104 and the sacrificial material 106 of each tier 108 of the preliminary stack structure 102 having horizontal ends defining an individual stadium structure 110 (e.g., the first stadium structure 110A) within the preliminary stack structure 102 may continuously horizontally extend in the X-direction across sides of the stadium structure 110 opposing one another in the Y-direction. In addition, for an individual stadium structure 110 within the preliminary stack structure 102, inner horizontal boundaries (e.g., inner sidewalls) of the preliminary stack structure 102 partially defining the trench 118 associated with (e.g., vertically overlying and within horizontal boundaries of) the stadium structure 110 may be oriented substantially perpendicular to uppermost vertical boundaries (e.g., uppermost surfaces) of the preliminary stack structure 102, or may be oriented substantially non-perpendicular to the uppermost vertical boundaries (e.g., uppermost surfaces) of the preliminary stack structure 102.
Referring next to FIG. 2A, which is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure 100 following the processing stage previously described with reference to FIGS. 1A through 1C, a first dielectric liner 120 may be formed on or over portions of the preliminary stack structure 102 defining the stadium structures 110 and the trenches 118. FIG. 2B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure 100 at the processing stage of FIG. 2A about a dashed line B-B shown in FIG. 2A.
For an individual trench 118, the first dielectric liner 120 may be formed to substantially continuously extend on or over surfaces (e.g., horizontally extending surfaces, vertically extending surfaces) of the stadium structure 110 and the preliminary stack structure 102 defining boundaries (e.g., horizontal boundaries, vertical boundaries) of the trench 118. The first dielectric liner 120 may be formed to substantially continuously extend on or over the opposing staircase structures 112 (e.g., the forward staircase structure 112A and the reverse staircase structure 112B) of each of the stadium structures 110, as well as on or over inner sidewalls of the preliminary stack structure 102 horizontally neighboring (e.g., in the Y-direction) each of the stadium structures 110.
The first dielectric liner 120 may be employed (e.g., serve) as a barrier material to protect (e.g., mask) the staircase structures 112 from removal during subsequent processing acts (e.g., subsequent etching acts, support structure formation, contact structure formation), as described in further detail below. The first dielectric liner 120 may be formed to have a desired thickness capable of protecting the staircase structures 112 during the subsequent processing acts. In some embodiments, a thickness of the first dielectric liner 120 is within a range of from about 2 nanometers (nm) to about 50 nm (e.g., from about 5 nm to about 40 nm).
The first dielectric liner 120 may be formed of and include at least one dielectric material having different etch selectivity than the sacrificial material 106 of the tiers 108 of the preliminary stack structure 102. By way of non-limiting example, the first dielectric liner 120 may be formed of and include one or more of at least one dielectric oxide material (e.g., one or more of SiOx, phosphosilicate glass, borosilicate glass, borophosphosilicate glass, fluorosilicate glass, AlOx, HfOx, NbO−x−, TiOx, ZrOx, TaOx, and a MgOx), at least one dielectric nitride material (e.g., SiNy), at least one dielectric oxynitride material (e.g., SiOxNy), at least one dielectric oxycarbide material (e.g., SiOxCy), at least one hydrogenated dielectric oxycarbide material (e.g., SiCxOyHz), at least one dielectric carboxynitride material (e.g., SiOxCzNy), and at least one semiconductive material (e.g., polycrystalline silicon). In some embodiments, the first dielectric liner 120 is formed of and includes a dielectric oxide material, such as SiOx, (e.g., SiO2). The first dielectric liner 120 may be substantially homogeneous, or may be heterogeneous.
Referring next to FIG. 3A, which is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure 100 following the processing stage previously described with reference to FIGS. 2A and 2B, a second dielectric liner 121 may be formed on or over at least some portions of the first dielectric liner 120. FIG. 3B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure 100 at the processing stage of FIG. 3A about a dashed line B-B shown in FIG. 3A.
The second dielectric liner 121 may be employed (e.g., serve) as an etch stop material during subsequent processing acts (e.g., subsequent etching acts) to form openings (e.g., contact openings, contact vias), as described in further detail below. The second dielectric liner 121 may be formed to substantially continuously extend on or over the first dielectric liner 120. The second dielectric liner 121 may be formed to horizontally overlap (e.g., in the X-direction, in the Y-direction) the steps 116 of the staircase structures 112 of the stadium structures 110 formed within the preliminary stack structure 102. The second dielectric liner 121 may have a different composition from the first dielectric liner 120. The second dielectric liner 121 may be formed to have a desired thickness capable of protecting the first dielectric liner 120 underlying the second dielectric liner 121 during the subsequent material removal acts. A thickness of the second dielectric liner 121 may, for example, be within a range of from about 10 nm to about 100 nm, such as from about 20 nm to about 80 nm.
The second dielectric liner 121 may be formed of and include at least one dielectric material having different etch selectivity than the first dielectric liner 120 and the dielectric fill material 124. The second dielectric liner 121 may, for example, have etch selectively substantially similar to that of the sacrificial material 106 of the tiers 108 of the preliminary stack structure 102. By way of non-limiting example, the second dielectric liner 121 may be formed of and include at least one nitrogen-containing dielectric material, such as at least one dielectric nitride material. In some embodiments, the second dielectric liner 121 is formed of and includes SiNy (e.g., Si3N4). The second dielectric liner 121 may be substantially homogeneous, or may be heterogeneous.
The second dielectric liner 121 may be formed using a relatively low temperature process. For example, the second dielectric liner 121 may be formed using a low temperature chemical vapor deposition (CVD) process employing a processing temperature less than or equal to about 700° C., such as within a range of from about 500° C. to about 700° C., or from about 550° C. to about 650° C.
The dielectric material of the second dielectric liner 121 may be doped with at least one chemical species (e.g., at least one dopant) that modifies the etch selectively of the second dielectric liner 121 relative to the sacrificial material 106 of the tiers 108 of the preliminary stack structure 102. The at least one chemical species may effectively decrease an etch rate of the second dielectric liner 121 relative to the sacrificial material 106 of the tiers 108 of the preliminary stack structure 102 during mutual exposure to a predetermined etchant (e.g., a predetermined wet etchant, such as a wet etchant include hydrofluoric acid, HF and/or a dry etchant). For example, the dielectric structure 122 may be doped with one or more of carbon (C) and boron (B).
Referring next to FIG. 4A, which is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure 100 following the processing stage previously described with reference to FIGS. 3A and 3B. Portions of the second dielectric liner 121 (FIGS. 3A and 3B) may be removed to form dielectric structures 122 (e.g., dielectric mesa structures, dielectric landing structures) on or over portions of the first dielectric liner 120. In some embodiments, the dielectric structures 122 may be substantially contained within horizontal areas of the steps 116 of the stadium structures 110, as illustrated in FIGS. 4A and 4B. The dielectric structures 122 may be formed to be separate and discrete from one another, and may be positioned within horizontal areas of different steps 116 than one another. In other embodiments, portions of the second dielectric liner 121 (FIGS. 3A and 3B) may not be removed, and a single (e.g., only one) dielectric structure 122 effectively corresponding to the second dielectric liner 121 (FIGS. 3A and 3B) may continuously extend on the first dielectric liner 120. Different portions of the single (e.g., only one) a dielectric structure 122 may be positioned within horizontal areas of different steps 116. In addition, a dielectric fill material 124 may be formed on or over the dielectric structures 122 and the first dielectric liner 120. The dielectric structure(s) 122 and the dielectric fill material 124 may together substantially fill portions of the trenches 118 (FIGS. 2A and 2B) remaining unfilled following the formation of the first dielectric liner 120. The first dielectric liner 120, the dielectric structure(s) 122, and the dielectric fill material 124 may together form filled trenches 126 individually vertically extending (e.g., in the Z-direction) through the preliminary stack structure 102. FIG. 4B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure 100 at the processing stage of FIG. 4A about a dashed line B-B shown in FIG. 4A.
The dielectric structure(s) 122 may similarly be employed (e.g., serve) as etch stop structures during subsequent processing acts (e.g., subsequent etching acts) to form openings (e.g., contact openings, contact vias) vertically extending through the dielectric fill material 124, as described in further detail below. As previously described herein, in some embodiments, the dielectric structures 122 are collectively formed to discontinuously extend on or over portions of the first dielectric liner 120 within horizontal boundaries of the stadium structures 110. Individual dielectric structures 122 may be positioned within horizontal boundaries of individual steps 116 of individual stadium structures 110 (e.g., individual steps 116 of the opposing staircase structures 112 thereof, such individual steps 116 the forward staircase structure 112A and/or individual steps 116 of the reverse staircase structure 112B) within the preliminary stack structure 102. As shown in FIG. 4A, for each stadium structure 110, at least one dielectric structure 122 may also be positioned within horizontal boundaries of the central region 114 of the stadium structure 110. Each dielectric structure 122 may be substantially confined within a horizontal area of the step 116 or central region 114 associated therewith. Each dielectric structure 122 within horizontal boundaries of an individual step 116 of an individual stadium structure 110 may have a horizontal area less than a horizontal area of the step 116. In addition, each dielectric structure 122 within horizontal boundaries of an individual central region 114 of an individual stadium structure 110 may have a horizontal area less than a horizontal area of the central region 114. Each dielectric structure 122 may be formed to have a desired thickness capable of protecting the first dielectric liner 120 underlying the dielectric structure 122 from during the subsequent processing acts to form the openings vertically extending through the dielectric fill material 124. In some embodiments, a thickness of each dielectric structure 122 is within a range of from about 10 nm to about 100 nm (e.g., from about 20 nm to about 80 nm).
As shown in FIGS. 4A and 4B, in some embodiments, vertically extending (e.g., in the Z-direction) surfaces of the first dielectric liner 120 are substantially free of the dielectric structures 122 thereon. For example, the dielectric structures 122 may be absent (e.g., omitted) from portions of the first dielectric liner 120 formed on or over vertically extending surfaces of the preliminary stack structure 102 partially defining boundaries of the trenches 118 (FIGS. 1A-1C), such as vertically extending surfaces of the stadium structures 110 and vertically extending surfaces (e.g., sidewalls) of portions of the preliminary stack structure 102 horizontally neighboring the stadium structures 110 (and, hence, also horizontally neighboring the trenches 118). Within horizontal boundaries of an individual stadium structure 110, each of the dielectric structures 122 may be horizontally offset in the X-direction from each other of the dielectric structures 122. In addition, within horizontal boundaries of an individual stadium structure 110, each of the dielectric structures 122 may be at least partially (e.g., substantially) horizontally aligned in the Y-direction with each other of the dielectric structures 122.
Discrete dielectric structures 122 may be formed by removing portions of the second dielectric liner 121 on or over vertically extending (e.g., in the Z-direction) surfaces of the first dielectric liner 120 within the trenches 118 (FIGS. 2A and 2B). Additional portions of the second dielectric liner 121 on or over horizontally extending surfaces of the first dielectric liner 120 within the trenches 118 (FIGS. 2A and 2B) that remain following the material removal process may form the dielectric structures 122. The portions of the second dielectric liner 121 on or over the vertically extending surfaces of the first dielectric liner 120 may be selectively removed relative to the additional portions of the second dielectric liner 121 on or over the horizontally extending surfaces of the first dielectric liner 120 by doping the portions or the additional portions with at least one chemical species (e.g., at least one dopant) that modifies the etch selectively of the portions relativity to the additional portions prior to mutual exposure of the portions and the additional portions to at least one etchant. For example, in the doping process described above, only the horizontal portions of the second dielectric liner 121 (e.g., the portions of the second dielectric liner 121 over the horizontal surfaces of the first dielectric liner 120 that will form the dielectric structures 122) may be doped with the at least one chemical species. In some embodiments, the horizontally extending portions of the second dielectric liner 121 are doped with a relatively greater amount of at least one chemical species than the vertically extending portions of the second dielectric liner 121, wherein the at least one chemical species effectively decreases an etch rate of the additional, horizontally extending portions relative to the vertically extending portions of the second dielectric liner 121 during mutual exposure to a predetermined etchant (e.g., a predetermined wet etchant, such as a wet etchant include hydrofluoric acid, HF). By way of non-limiting example, the additional, horizontally extending portions of the dielectric material may be doped with a relatively greater amount of carbon (C) or boron (B) than the vertically extending portions of the dielectric material. In additional embodiments, the vertically extending portions of the dielectric material are doped with a relatively greater amount of at least one chemical species than the additional, horizontally extending portions of the dielectric material, wherein the at least one chemical species effectively increases an etch rate of the vertically extending portions relative to the additional, horizontally extending portions during mutual exposure to a predetermined etchant.
As also previously described herein, in other embodiments, a single, dielectric structure 122 is formed to continuously extend across horizontally extending surfaces and vertically extending surfaces of the first dielectric liner 120 (and hence of the preliminary stack structure 102 thereunder). For example, the second dielectric liner 121 (FIGS. 3A and 3B) may effectively form the single dielectric structure 122 without having portions of the second dielectric liner 121 removed to form discrete dielectric structures 122. Thus, the second dielectric liner 121 may be positioned between the dielectric fill material 124 and the first dielectric liner 120 over the entire stadium structure 110 including over horizontally extending surfaces of the steps 116 thereof and over vertically extending surfaces of the steps 116 thereof.
Still referring to FIGS. 4A and 4B, the dielectric fill material 124 may substantially fill portions of the trenches 118 (FIGS. 2A and 2B) unoccupied by the first dielectric liner 120 and the dielectric structure(s) 122. The dielectric fill material 124 may be formed to substantially continuously extend on or over the dielectric structure(s) 122 and the first dielectric liner 120. The dielectric fill material 124 may be formed to exhibit a substantially planar upper vertical boundary, and a substantially non-planar lower vertical boundary complementary to (e.g., substantially mirroring) a topography thereunder.
As shown in FIGS. 4A and 4B, within horizontal boundaries of each of the stadium structures 110, the dielectric fill material 124 covers and surrounds the dielectric structure(s) 122. For example, the dielectric fill material 124 may substantially cover and surround horizontally extending upper surfaces and vertically extending side surfaces of each of the dielectric structure(s) 122. In addition, within horizontal boundaries of each of the stadium structures 110, the dielectric fill material 124 also covers portions of the first dielectric liner 120 not covered by the dielectric structure(s) 122. For example, the dielectric fill material 124 may substantially cover surfaces (e.g., horizontally extending surfaces, vertically extending surfaces) of the first dielectric liner 120 not covered by the dielectric structure(s) 122. Portions of the dielectric fill material 124 may be horizontally interposed (e.g., in the X-direction, in the Y-direction) between the dielectric structures 122 and the first dielectric liner 120.
The dielectric fill material 124 may be formed of and include at least one dielectric material having different etch selectivity than the dielectric structure(s) 122. The dielectric fill material 124 may, for example, have etch selectively substantially similar to that of one or more of the first dielectric liner 120 the insulative material 104 of the tiers 108 of the preliminary stack structure 102. By way of non-limiting example, the dielectric fill material 124 may be formed of and include at least one oxygen-containing dielectric material, such as a one or more of at least one dielectric oxide material (e.g., one or more of SiOx, phosphosilicate glass, borosilicate glass, borophosphosilicate glass, fluorosilicate glass, AlOx, HfOx, NbOx, and TiOx), at least one dielectric oxynitride material (e.g., SiOxNy), and at least one dielectric carboxynitride material (e.g., SiOxCzNy). In some embodiments, the dielectric fill material 124 is formed of and includes SiOx (e.g., SiO2).
FIGS. 5A-5C illustrate simplified, enlarged longitudinal cross-sectional views of one of the dielectric structures 122 of the microelectronic device structure 100 (FIGS. 4A and 4B) at the processing stage of FIGS. 4A and 4B, in accordance with embodiments of the disclosure. As shown in each of FIGS. 5A-5C, the dielectric structures 122 of the microelectronic device structure 100 (FIGS. 4A and 4B) may individually include an upper surface 504 proximate the dielectric fill material 124 (FIGS. 4A and 4B) and a lower surface 506 proximate the first dielectric liner 120 (FIGS. 4A and 4B). As shown in FIG. 5A, a dopant 502 (e.g., carbon and/or boron) may be implanted into the dielectric structure 122. The dielectric structure 122 may include an atomic concentration of the dopant 502 within a range of from about 1E14 atoms dopant/cm2 to about 10E16 atoms dopant/cm2, such as between about 5E14 atoms dopant/cm2 and about 2E16 atoms dopant/cm2. An atomic percentage of the dopant 502 within an individual dielectric structure 122 may be within a range of from about 0.5 atomic percent (atomic %) and to about 20 atomic % such as from about 1 atomic % to about 10 atomic %.
The dopant concentration may vary (e.g., may be non-uniform) throughout a vertical thickness (e.g., a vertical height in the Z-direction) of an individual dielectric structure 122. The varying dopant concentration may form a non-uniform (e.g., variable) dopant concentration profile within an individual dielectric structure 122. The variations in dopant concentration throughout the vertical thickness of the dielectric structure 122 may be controlled by controlling a penetration energy during the doping process. For example, increasing the penetration energy during the doping process may cause the dopants 502 to be implanted to relatively deeper depths within the dielectric structure 122, which may result in a relatively greater concentrations of dopants 502 proximate the lower surface 506. Alternatively, decreasing the penetration energy during the doping process may cause the dopant 502 to be implanted to relatively shallower depths within the dielectric structure 122, which may result in a relatively greater concentration of dopants 502 proximate the upper surface 504. The penetration energy may be controlled to be within a range of from about 0.5 kiloelectronvolt (keV) to about 100 keV, such as from about 1 keV to about 60 keV.
As described above, the presence of dopants 502 in the dielectric structure 122 may modify the etch rate of dielectric material (e.g., dielectric nitride material) of the dielectric structure 122. Modifying the etch rate of the dielectric material of the dielectric structure 122 may restrict a subsequent etching process, such as a dry etching process used to form a hole or opening through the dielectric fill material 124 as described in further detail below. Restricting the etching process may substantially prevent the etching process from bypassing the dielectric structure 122 on a side and/or from punching through the dielectric structure 122. The concentration profile of the dopants 502 in the dielectric structure 122 may affect a geometric configuration (e.g., shape, dimensions) of the dielectric structure 122 after an etching process, such as the etching process described above to form multiple discrete dielectric structures 122, or a subsequent etching process to form contact openings vertically extending through the dielectric fill material 124, the dielectric structures 122, the first dielectric liner 120 and the tiers 108 of the preliminary stack structure 102.
FIG. 5B illustrates a dielectric structure 122 after an etching process. The dielectric structure 122 may have a concentration profile that is biased toward the upper surface 504. In other words, the dielectric structure 122 may have a relatively greater concentration of the dopants 502 proximate the upper surface 504 than proximate the lower surface 506. This may result in an upper region 510 that has a relatively slower etch rate than a lower region 512. The difference in etch rates between the upper region 510 and the lower region 512 may result in side surfaces 508 of the dielectric structure 122 that slope inward from the upper surface 504 to the lower surface 506. The difference in etch rates may cause the lower surface 506 to have a relatively smaller horizontal area than the upper surface 504.
FIG. 5C illustrates a dielectric structure 122 after an etching process. The dielectric structure 122 may have a concentration profile that is biased toward the lower surface 506. In other words, the dielectric structure 122 may have a relatively greater concentration of dopants 502 proximate the lower surface 506 than proximate the upper surface 504. This may result in the upper region 510 having a relatively faster etch rate than the lower region 512. The difference in etch rates between the upper region 510 and the lower region 512 may result in the side surfaces 508 of the dielectric structure 122 sloping outward from the upper surface 504 to the lower surface 506. The difference in etch rates may cause the lower surface 506 to have a relatively larger horizontal area than the upper surface 504.
A dielectric structure 122 having a concentration profile that is substantially even (e.g., uniform) throughout the dielectric structure 122 may have result in side surfaces 508 oriented substantially perpendicular to the upper surface 504 and the lower surface 506 following an etching process, similar to the configuration illustrated in FIG. 5A. The concentration profile may affect the response of the dielectric structure 122 to a dry etching process when forming the openings through the dielectric fill material 124. For example, an even concentration profile and/or a concentration profile biased toward the upper surface 504 may substantially prevent the dry etch from passing through and/or around the dielectric structure 122 due to the reduced etch rate of the upper region 510 of the associated dielectric structure 122.
As described in further detail below with reference to FIG. 6C, the microelectronic device structure 100 may be formed to further include contact structures vertically extending through the preliminary stack structure 102. Some of the contact structures may be employed as support structures configured and positioned to support the tiers 108 of the preliminary stack structure 102 during subsequent processing (e.g., replacement gate processing) of the microelectronic device structure 100. For example, the some of the contact structures may be configured and positioned to impede (e.g., substantially prevent) collapse of portions of the insulative material 104 of the tiers 108 with horizontal areas of the stadium structures 110 during subsequent replacement gate processing acts.
Referring next to FIG. 6A, which is a simplified, partial perspective view of a microelectronic device structure 100 following the processing stage previously described with reference to FIGS. 4A and 4B, the preliminary stack structure 102 (FIGS. 4A and 4B) may be partitioned (e.g., divided, segmented) and subject to replacement gate processing to form a stack structure 128. The stack structure 128 may be divided into blocks 130 separated from one another by slot structures 132. The slot structures 132 may vertically extend (e.g., in the Z-direction) completely through the stack structure 128. Additional features (e.g., materials, structures) of the stack structure 128 (including the blocks 130 thereof) are described in further detail below. In FIG. 6A, for clarity and ease of understanding the drawings and associated description, the slot structures 132 are depicted as transparent to more clearly show features of the blocks 130. FIG. 6B is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure 100 at the processing stage depicted in FIG. 6A. FIG. 6C is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure 100 at the processing stage of FIGS. 6A and 6B about a dashed line B-B shown in FIG. 6B.
As shown in FIG. 6A, the blocks 130 of the stack structure 128 may be formed to horizontally extend parallel in an X-direction. As used herein, the term “parallel” means substantially parallel. Horizontally neighboring blocks 130 of the stack structure 128 may be separated from one another in a Y-direction orthogonal to the X-direction by the slot structures 132. The slot structures 132 may also horizontally extend parallel in the X-direction. Each of the blocks 130 of the stack structure 128 may exhibit substantially the same geometric configuration (e.g., substantially the same dimensions and substantially the same shape) as each other of the blocks 130, or one or more of the blocks 130 may exhibit a different geometric configuration (e.g., one or more different dimensions and/or a different shape) than one or more other of the blocks 130. In addition, each pair of horizontally neighboring blocks 130 of the stack structure 128 may be horizontally separated from one another by substantially the same distance (e.g., corresponding to a width in the Y-direction of each of the slot structures 132) as each other pair of horizontally neighboring blocks 130 of the stack structure 128, or at least one pair of horizontally neighboring blocks 130 of the stack structure 128 may be horizontally separated from one another by a different distance than that separating at least one other pair of horizontally neighboring blocks 130 of the stack structure 128. In some embodiments, the blocks 130 of the stack structure 128 are substantially uniformly (e.g., substantially non-variably, substantially equally, substantially consistently) sized, shaped, and spaced relative to one another.
Each of the blocks 130 of the stack structure 128 may be formed to include a vertically alternating (e.g., in a Z-direction) sequence of insulative structures 134 and conductive structures 136 arranged in tiers 138. For an individual blocks 130 of the stack structure 128, each of the tiers 138 may individually include one of the conductive structures 136 vertically neighboring (e.g., directly vertically adjacent) one of the insulative structures 134. The insulative structures 134 of the blocks 130 of the stack structure 128 may comprise portions of the insulative material 104 (FIGS. 4A and 4B) of the preliminary stack structure 102 (FIGS. 4A and 4B) remaining following the formation of the blocks 130. The conductive structures 136 of the blocks 130 of the stack structure 128 may comprise at least one conductive material formed (e.g., deposited) in place of the sacrificial material 106 (FIGS. 4A and 4B) of the preliminary stack structure 102 (FIGS. 4A and 4B) through the replacement gate process, as described in further detail below. The conductive material may formed of and include one or more of at least one conductively doped semiconductor material, at least one metal, at least one alloy, and at least one conductive metal-containing material (e.g., at last one conductive metal nitride, at least one conductive metal silicide, at least one conductive metal carbide, at least one conductive metal oxide). In some embodiments, the conductive structures 136 are formed of and includes tungsten (W). Optionally, at least one liner material (e.g., at least one insulative liner material, at least one conductive liner materials) may be formed around the conductive structures 136. The liner material may, for example, be formed of and include one or more a metal (e.g., titanium, tantalum), an alloy, a metal nitride (e.g., tungsten nitride, titanium nitride, tantalum nitride), and a metal oxide (e.g., aluminum oxide). In some embodiments, the liner material comprises at least one conductive material employed as a seed material for the formation of the conductive structures 136. In some embodiments, the liner material comprises titanium nitride (TiNx, such as TiN). In further embodiments, the liner material further includes aluminum oxide (AlOx, such as Al2O3). As a non-limiting example, for each of the block 130 of the stack structure 128, AlOx (e.g., Al2O3) may be formed directly adjacent the insulative structures 134, TiNx (e.g., TiN) may be formed directly adjacent the AlOx, and W may be formed directly adjacent the TiNx. For clarity and ease of understanding the description, the liner material is not illustrated in FIGS. 6A-6C, but it will be understood that the liner material may be disposed around the conductive structures 136.
Within each block 130 of the stack structure 128, one or more conductive structures 136 of one or more relatively vertically higher tiers 138 (e.g., upper tiers) may be employed to form upper select gate structures (e.g., drain side select gate (SGD) structures) for upper select transistors (e.g., drain side select transistors) of the block 130. The conductive structures 136 of the relatively vertically higher tiers 138 may be segmented by one or more filled slot(s) (e.g., filled SGD slot(s)) to form the upper select gate structures of the block 130. In some embodiments, within each block 130 of the stack structure 128, the conductive structures 136 of each of less than or equal to eight (8) relatively higher tiers 138 (e.g., from one (1) relatively vertically higher tier 138 to eight (8) relatively vertically higher tiers 138) of the stack structure 128 is employed to form upper select gate structures (e.g., SGD structures) for the block 130. In addition, within each block 130 of the stack structure 128, the conductive structures 136 of at least some relatively vertically lower tiers 138 vertically underlying the relatively vertically higher tiers 138 may be employed to form access line structures (e.g., word line structures) of the block 130. Moreover, within each block 130 of the stack structure 128, the conductive structures 136 of at least a vertically lowest tier 138 may be employed to form as at least one lower select gate structure (e.g., at least one source side select gate (SGS) structure) for lower select transistors (e.g., source side select transistors) of the block 130.
To form the stack structure 128, including the blocks 130 thereof, slots (e.g., trenches, openings, apertures) having geometric configurations (e.g., shapes, dimensions) and positions corresponding to (e.g., substantially the same as) having geometric configurations (e.g., shapes, dimensions) and positions of the slot structures 132 may be formed in the preliminary stack structure 102 (FIGS. 4A and 4B). Thereafter, the microelectronic device structure 100 may be treated with at least one wet etchant formulated to selectively remove portions of the sacrificial material 106 (FIGS. 4A and 4B) of the tiers 108 (FIGS. 4A and 4B) of the preliminary stack structure 102 (FIGS. 4A and 4B) through the slots. The wet etchant may be selected to remove the portions of the sacrificial material 106 (FIGS. 4A and 4B) without substantially removing portions of the insulative material 104 (FIGS. 4A and 4B) of the tiers 108 (FIGS. 4A and 4B) of the preliminary stack structure 102 (FIGS. 4A and 4B), and without substantially removing portions of the first dielectric liner 120. During the material removal process, the first dielectric liner 120 may protect (e.g., mask) the dielectric structures 122 from being removed. In some embodiments wherein the sacrificial material 106 (FIGS. 4A and 4B) comprises a dielectric nitride material (e.g., SiNy, such as Si3N4) and the insulative material 104 and the first dielectric liner 120 comprise a dielectric oxide material (e.g., SiOx, such as SiO2), the sacrificial material 106 (FIGS. 4A and 4B) of the tiers 108 (FIGS. 4A and 4B) of the preliminary stack structure 102 (FIGS. 4A and 4B) is at selectively removed using a wet etchant comprising H3PO4. Following the selective removal of the portions of the sacrificial material 106 (FIGS. 3A and 3B), the resulting recesses may be filled with conductive material to form the conductive structures 136 of the blocks 130 of the stack structure 128. In addition, following the formation of the blocks 130, the slots between the blocks 130 may be filled (e.g., substantially filled) with at least one dielectric material (e.g., at least one dielectric oxide material, such as SiOx; at least one dielectric nitride material, such as SiNy) to form the slot structures 132. In some embodiments, the slot structures 132 are formed of and include SiO2. The slot structures 132 may individually be formed to be substantially homogeneous, or may individually be formed to be heterogeneous.
Referring again to FIG. 6A, each block 130 of the stack structure 128 may individually be formed to include a row of the stadium structures 110 (e.g., including the first stadium structure 110A, the second stadium structure 110B, the third stadium structure 110C, and the fourth stadium structure 110D of the row), crest regions 140 (e.g., elevated regions), and bridge regions 142 (e.g., additional elevated regions). The stadium structures 110 may be distributed throughout and substantially confined within a horizontal area of the block 130. The crest regions 140 may be horizontally interposed between stadium structures 110 horizontally neighboring one another in the X-direction. The bridge regions 142 may horizontally neighbor opposing sides of individual stadium structures 110 in the Y-direction, and may horizontally extend from and between crest regions 140 horizontally neighboring one another in the X-direction. In FIG. 6A, for clarity and ease of understanding the drawings and associated description, portions (e.g., some of the bridge regions 142 horizontally neighboring first sides of the stadium structures 110 in the Y-direction) of one of the blocks 130 of the stack structure 128 are depicted as transparent to more clearly show the stadium structures 110 distributed within the block 130.
As shown in FIG. 6A, the crest regions 140 of an individual block 130 of the stack structure 128 may intervene between and separate stadium structures 110 horizontally neighboring one another in the X-direction. For example, one of the crest regions 140 may intervene between and separate the first stadium structure 110A and the second stadium structure 110B, an additional one of the crest regions 140 may intervene between and separate the second stadium structure 110B and the third stadium structure 110C; and a further one of the crest regions 140 may intervene between and separate the third stadium structure 110C and the fourth stadium structure 110D. A vertical height of the crest regions 140 in the Z-direction may be substantially equal to a maximum vertical height of the block 130 in the Z-direction; and a horizontal width of the crest regions 140 in the Y-direction may be substantially equal to a maximum horizontal width of the block 130 in the Y-direction. In addition, each of the crest regions 140 may individually exhibit a desired horizontal length in the X-direction. Each of the crest regions 140 of an individual block 130 of the stack structure 128 may exhibit substantially the same horizontal length in the X-direction as each other of the crest regions 140 of the block 130; or at least one of the crest regions 140 of the block 130 may exhibit a different horizontal length in the X-direction than at least one other of the crest regions 140 of the block 130.
Still referring to FIG. 6A, the bridge regions 142 of an individual block 130 of the stack structure 128 may be formed to intervene between and separate the stadium structures 110 of the block 130 from the slot structures 132 horizontally neighboring the block 130 in the Y-direction. For example, for each stadium structure 110 within an individual block 130 of the stack structure 128, a first bridge region 142A may be horizontally interposed in the Y-direction between a first side of the stadium structure 110 and a first of the slot structures 132 horizontally neighboring the block 130; and a second bridge region 142B may be horizontally interposed in the Y-direction between a second side of the stadium structure 110 and a second of the slot structures 132 horizontally neighboring the block 130. The first bridge region 142A and the second bridge region 142B may horizontally extend in parallel in the X-direction. In addition, the first bridge region 142A and the second bridge region 142B may each horizontally extend from and between crest regions 140 of the block 130 horizontally neighboring one another in the X-direction. The bridge regions 142 of the block 130 may be integral and continuous with the crest regions 140 of the block 130. Upper boundaries (e.g., upper surfaces) of the bridge regions 142 may be substantially coplanar with upper boundaries of the crest regions 140. A vertical height of the bridge regions 142 in the Z-direction may be substantially equal to a maximum vertical height of the block 130 in the Z-direction. In addition, each of the bridge regions 142 (including each first bridge region 142A and each second bridge region 142B) may individually exhibit a desired horizontal width in the Y-direction and a desired horizontal length in the X-direction. Each of the bridge regions 142 of the block 130 may exhibit substantially the same horizontal length in the X-direction as each other of the bridge regions 142 of the block 130; or at least one of the bridge regions 142 of the block 130 may exhibit a different horizontal length in the X-direction than at least one other of the bridge regions 142 of the block 130. In addition, each of the bridge regions 142 of the block 130 may exhibit substantially the same horizontal width in the Y-direction as each other of the bridge regions 142 of the block 130; or at least one of the bridge regions 142 of the block 130 may exhibit a different horizontal width in the Y-direction than at least one other of the bridge regions 142 of the block 130.
For each block 130 of the stack structure 128, the bridge regions 142 thereof horizontally extend around the filled trenches 126 of the block 130. Some of the bridge regions 142 of the block 130 may be employed to form continuous conductive paths extending from and between horizontally neighboring crest regions 140 of the block 130. As shown in FIG. 6C, the first dielectric liner 120 of the filled trenches 126 may be positioned directly horizontally adjacent (e.g., in the Y-direction) inner side surfaces (e.g., inner sidewalls) of the bridge regions 142, and the slot structures 132 may be positioned directly horizontally adjacent (e.g., in the Y-direction) outer side surfaces (e.g., outer sidewalls) of the bridge regions 142. As described above, in some embodiments, vertically extending portions of first dielectric liner 120 directly horizontally adjacent the inner side surfaces of the bridge regions 142 may be substantially free of the dielectric structures 122 thereon. Instead, the dielectric fill material 124 of the filled trenches 126 may be positioned directly horizontally adjacent (e.g., in the Y-direction) and may substantially cover inner side surfaces (e.g., inner sidewalls) of the vertically extending portions of first dielectric liner 120. In addition, for each filled trench 126, the first dielectric liner 120 may be vertically interposed between upper boundaries of the steps 116 of the stadium structure 110 associated with the filled trench 126 and lower boundaries of the dielectric structures 122 within horizontal boundaries of the steps 116. In other embodiments, such as the embodiments described above where the second dielectric liner 121 remains substantially intact to form the dielectric structure 122, the dielectric structure 122 may remain continuous over the vertically extending portions.
Referring to FIG. 6C, during and after the replacement gate process to form the stack structure 128, the configuration of the filled trenches 126 (including the configurations of the first dielectric liner 120, the dielectric structures 122, and the dielectric fill material 124 thereof) provides several advantages. For example, the configuration of the first dielectric liner 120 of each filled trench 126 protects the dielectric structures 122 of the filled trenches 126 from removal and replacement with conductive material during the replacement gate process, and thus prevents the formation of undesirable void spaces that may otherwise result from replacing the dielectric structures 122 with the conductive material. Such void spaces may, for example, otherwise be formed at interfaces of the conductive material that would replace the dielectric structures 122 and the conductive structures 136 of individual blocks 130 of the stack structure 128 at steps 116 of the stadium structures 110. Maintaining the dielectric structures 122 also facilitates subsequent use of the dielectric structures 122 as so-called “etch stop” structures to mitigate (e.g., prevent) undesirable damage (e.g., over-etching damage, punch-through damage) to tiers 138 of individual blocks 130 of the stack structure 128 during subsequent processing to form contact openings within boundaries of the stadium structures 110 within the blocks 130, as described in further detail below. As another example, in embodiments wherein discrete dielectric structures 122 are employed within individual filled trenches 126, the configurations of the dielectric structures 122 may reduce the risk of damage and/or defects, and/or may reduce processing complexities relative to the use of a dielectric structure 122 that extends across and substantially covers (e.g., substantially lines) vertically extending portions of first dielectric liner 120. Omitting the dielectric structures 122 from vertically extending portions of the first dielectric liner 120 may, for example, mitigate the risk of undesirable short circuits between the conductive structures 136 of different tiers 138 of an individual block 130 that may otherwise result from defects within the first dielectric liner 120 ahead of the replacement gate processing. Such defects may, for example, otherwise provide an access point for undesirable replacement of vertically extending portions of such dielectric structure configurations with conductive material during the replacement gate processing.
Still referring to FIG. 6C, each block 130 of the stack structure 128 may individually be formed to have a desired distribution of contact structures 141 (e.g., support contacts, support pillars) (depicted by way of dashed lines in FIG. 6C) vertically extending therethrough. The contact structures 141 may, for example, be formed in the preliminary stack structure 102 (FIGS. 4A and 4B) prior to the replacement gate processing to form the conductive structures 136 of the blocks 130 of the stack structure 128. The contact structures 141 may be configured and positioned to facilitating support of the insulative material 104 (FIGS. 4A and 4B) of each of the tiers 108 (FIGS. 4A and 4B) of the preliminary stack structure 102 (FIGS. 4A and 4B) during replacement of the sacrificial material 106 (FIGS. 4A and 4B) of the tiers 108 (FIGS. 4A and 4B) with the conductive structures 136. In some embodiments, each block 130 of the stack structure 128 includes at least one array of the contact structures 141 vertically extending therethrough, including rows of the contact structures 141 extending in the X-direction, and columns of the contact structures 141 extending in the Y-direction. For each block 130, portions of the at least one array of the contact structures 141 may be located within horizontal areas of the stadium structures 110 within the block 130.
The contact structures 141 may each individually be formed to exhibit a desired horizontal cross-sectional shape. In some embodiments, each of the contact structures 141 is formed to exhibit a substantially circular horizontal cross-sectional shape. In additional embodiments, one or more (e.g., each) of the contact structures 141 exhibits a non-circular cross-sectional shape, such as one of more of a square cross-sectional shape, a rectangular cross-sectional shape, an oblong cross-sectional shape, an elliptical cross-sectional shape, a tear drop cross-sectional shape, a semicircular cross-sectional shape, a tombstone cross-sectional shape, a crescent cross-sectional shape, a triangular cross-sectional shape, a kite cross-sectional shape, and an irregular cross-sectional shape. In addition, each of the contact structures 141 may be formed to exhibit substantially the same horizontal cross-sectional dimensions (e.g., substantially the same horizontal diameter), or at least one of the contact structures 141 may be formed to exhibit one or more different horizontal cross-sectional dimensions (e.g., a different horizontal diameter) than at least one other of the contact structures 141. In some embodiments, all of the contact structures 141 are formed to exhibit substantially the same horizontal cross-sectional dimensions.
The contact structures 141 may each individually be formed of and include at least one conductive material, such as one or more of at least one metal (e.g., W, Ti, Mo, Nb, V, Hf, Ta, Cr, Zr, Fe, Ru, Os, Co, Rh, Ir, Ni, Pa, Pt, Cu, Ag, Au, Al), at least one alloy (e.g., a Co-based alloy, an Fe-based alloy, an Ni-based alloy, an Fe- and Ni-based alloy, a Co- and Ni-based alloy, an Fe- and Co-based alloy, a Co- and Ni- and Fe-based alloy, an Al-based alloy, a Cu-based alloy, a Mg-based alloy, a Ti-based alloy, a steel, a low-carbon steel, a stainless steel), at least one conductive metal-containing material (e.g., a conductive metal nitride, a conductive metal silicide, a conductive metal carbide, a conductive metal oxide), and at least one conductively-doped semiconductor material (e.g., conductively-doped Si, conductively-doped Ge, conductively-doped SiGe). In addition, at least one insulative liner material may be formed to substantially surround (e.g., substantially horizontally and vertically cover) side surfaces (e.g., sidewalls) of each of the contact structures 141. The insulative liner material may be horizontally interposed between the contact structures 141 and the tiers 138 of the blocks 130 of the stack structure 128. The insulative liner material may be formed of and include one or more of at least one dielectric oxide material (e.g., one or more of SiOx, phosphosilicate glass, borosilicate glass, borophosphosilicate glass, fluorosilicate glass, AlOx, HfOx, NbOx, TiOx, ZrOx, TaOx, and MgOx), at least one dielectric nitride material (e.g., SiNy), at least one dielectric oxynitride material (e.g., SiOxNy), at least one dielectric carboxynitride material (e.g., SiOxCzNy), and amorphous carbon. In some embodiments, the insulative liner material comprises SiO2.
At least some of the contact structures 141 may be formed by subjecting the microelectronic device structure 100 to at least one etching process to form contact openings vertically extending through the filled trenches 126 (including the dielectric fill material 124, the dielectric structures 122, and the first dielectric liner 120 thereof) and portions of the preliminary stack structure 102 (FIGS. 4A and 4B) within horizontal areas of the filled trenches 126. During the etching process, the relatively greater etch resistivity of the dielectric structures 122 facilitated by the dopants 502 (FIG. 5A) (e.g., C and/or B) therein may reduce lateral dimensions (e.g., diameters) of the contact openings at vertical elevations of the dielectric structures 122 as compared to conventional dielectric structures (e.g., conventional dielectric pad structures) not doped with the dopants 502, such that remaining portions of the dielectric structures 122 exhibit relatively greater horizontal areas than the conventional dielectric structures. The relatively greater horizontal areas of the dielectric structures 122 may, in turn, alleviate the risk of processing damage and/or processing complexities otherwise associated with the relatively smaller horizontal areas of conventional dielectric structures, such as the risk of undesirable bypass of the dielectric structures 122 during subsequent etching processes to form additional contact openings extending to the steps 116 of the stadium structures 110. Following the formation of the contact openings, the contact openings may be filled with the insulative liner material and the conductive material to form the contact structures 141.
Referring next to FIG. 7A, which is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure 100 following the processing stage previously described with reference to FIGS. 6A through 6C, for each block 130 of the stack structure 128, portions of at least the dielectric fill material 124, the dielectric structures 122, and the first dielectric liner 120 are removed (e.g., etched) to form contact openings 144 (e.g., apertures, vias) vertically extending (e.g., in the Z-direction) therethrough. The contact openings 144 may also individual vertically extend through the insulative structure 134 of a tier 138 of the block 130. The contact openings 144 may vertically extend to or into steps 116 of one or more (e.g., each) of the stadium structures 110, such as steps 116 of the forward staircase structure 112A of one or more of the stadium structures 110 and/or steps 116 of the reverse staircase structure 112B of one or more of the stadium structures 110. A bottom (e.g., lower vertical end) of each contact opening 144 may expose and be defined by an upper surface of the conductive structures 136 of an individual tier 138 of the stack structure 128 at an individual step 116 of an individual stadium structure 110 of an individual block 130 of the stack structure 128. FIG. 7B is a simplified, partial longitudinal cross-sectional view of a portion of the microelectronic device structure 100 at the processing stage of FIG. 7A about a dashed line B-B shown in FIG. 7A.
Within each block 130 of the stack structure 128, each contact opening 144 may be formed at desired a horizontal position (e.g., in the X-direction and the Y-direction) on or over one of the steps 116 of one of the stadium structures 110. In some embodiments, within a horizontal area of one or more of the stadium structures 110, at least some of the contact openings 144 are horizontally offset in the Y-direction from at least some other of the contact openings 144. In FIG. 5A, such horizontal offset is depicted by way of dashed lines at the boundaries (e.g., horizontal boundaries, vertical boundaries) of the contact openings 144. In addition, individual steps 116 of an individual stadium structure 110 (e.g., individual steps 116 of the forward staircase structure 112A thereof, individual steps 116 of the reverse staircase structure 112B thereof) may have a single (e.g., only one) contact opening 144 vertically extending thereto, may have multiple (e.g., more than one) contact openings 144 vertically extending thereto, or may have no contact openings 144 vertically extending thereto.
The contact openings 144 may each individually be formed to exhibit a desired horizontal cross-sectional shape. In some embodiments, each of the contact openings 144 is formed to exhibit a substantially circular horizontal cross-sectional shape. In additional embodiments, one or more (e.g., each) of the contact openings 144 exhibits a non-circular cross-sectional shape, such as one more of an oblong cross-sectional shape, an elliptical cross-sectional shape, a square cross-sectional shape, a rectangular cross-sectional shape, a tear drop cross-sectional shape, a semicircular cross-sectional shape, a tombstone cross-sectional shape, a crescent cross-sectional shape, a triangular cross-sectional shape, a kite cross-sectional shape, and an irregular cross-sectional shape. In addition, each of the contact openings 144 may be formed to exhibit substantially the same horizontal cross-sectional dimensions (e.g., substantially the same horizontal diameter), or at least one of the contact openings 144 may be formed to exhibit one or more different horizontal cross-sectional dimensions (e.g., a different horizontal diameter) than at least one other of the contact openings 144. In some embodiments, all of the contact openings 144 are formed to exhibit substantially the same horizontal cross-sectional dimensions.
The contact openings 144 may be formed using multiple material removal acts. For example, portions of the dielectric fill material 124 may be removed using a first material removal act (e.g., a first etching process) to form preliminary contact openings vertically extending to and exposing portions of the dielectric structures 122; and then portions of at least the dielectric structures 122 and the first dielectric liner 120 within horizontal boundaries of the preliminary contact openings may be removed using a second material removal act (e.g., a second etching process) to vertically extend the preliminary contact openings to the steps 116 of the stadium structures 110 and form the contact openings 144. As shown in FIG. 5A, depending on the sequence of the conductive structures 136 and the insulative structures 134 of the blocks 130 of the stack structure 128, the second material removal act extend the preliminary contact openings through insulative structures 134 of tiers 138 of the blocks 130 defining the steps 116 of the stadium structures 110. As a non-limiting example, the first material removal act may comprise a first etching process (e.g., anisotropic dry etching, such as one or more of RIE, deep RIE, plasma etching, reactive ion beam etching, and chemically assisted ion beam etching); and the second material removal act may comprise a second, different etching process (e.g., a so-called “punch through” etch). During the first etching process, the dielectric structures 122 may serve as a so-called “etch stop” structures to protect underlying portions of the dielectric liner 120 and the stack structure 128 from removal.
As described above, the dopants 502 (FIGS. 5A-5C) may decrease the etch rate of the dielectric structures 122 relative to the surrounding materials, such as the dielectric fill material 124, the first dielectric liner 120, and the tiers 138 of the stack structure 128. The decreased etch rate may substantially prevent the first etching process from etching through the dielectric structure (e.g., punch through). Successfully, stopping the first etching process, may result in improved accuracy of the subsequent etching processes into the stack structure 128, such that the contact opening 144 may expose the correct conductive structure 136 of the stack structure 128 without penetrating into neighboring conductive structures 136.
Referring next to FIG. 8A, which is a simplified, longitudinal cross-sectional view of the portion A of the microelectronic device structure 100 following the processing stage previously described with reference to FIGS. 7A and 7B, contact structures 146 may be formed within the contact openings 144 (FIGS. 7A and 7B). The contact structures 146 may be substantially confined within boundaries (e.g., horizontal boundaries, vertical boundaries) of the contact openings 144 (FIGS. 7A and 7B), and may substantially fill the contact openings 144 (FIGS. 7A and 7B). Each contact structure 146 may have a geometric configuration (e.g., shape, dimensions) corresponding to (e.g., substantially the same as) a geometric configuration of the contact opening 144 (FIGS. 7A and 7B) filled with the contact structure 146. As shown in FIG. 8A, each contact structure 146 may have an uppermost vertical boundary (e.g., an uppermost surface) substantially coplanar with an uppermost vertical boundary (e.g., an uppermost surface) of the dielectric fill material 124, and a lowermost vertical boundary (e.g., a lowermost surface) vertically adjacent an uppermost vertical boundary (e.g., an uppermost surface) of the conductive structure 136 of an individual tier 138 of an individual block 130 the stack structure 128. In additional embodiments, one or more (e.g., each) of the contact structures 146 may have an uppermost vertical boundary offset from (e.g., vertically over, vertically under) an uppermost vertical boundary (e.g., an uppermost surface) of the dielectric fill material 124. Each contact structure 146 may individually contact (e.g., physically contact, electrically contact) the conductive structure 136 of the individual tier 138 of the stack structure 128 at an individual step 116 of an individual stadium structure 110 of an individual block 130 of the stack structure 128.
The contact structures 146 may be formed of and include conductive material. As a non-limiting example, the contact structures 146 may be formed of and include one or more of at least one metal, at least one alloy, and at least one conductive metal-containing material (e.g., a conductive metal nitride, a conductive metal silicide, a conductive metal carbide, a conductive metal oxide). A material composition of the contact structures 146 may be substantially the same as a material composition of the conductive structures 136 of the tiers 138 of the blocks 130 of the stack structure 128, or the material composition of the contact structures 146 may be different than the material composition of the conductive structures 136 of the tiers 138 of the blocks 130 of the stack structure 128. In some embodiments, the contact structures 146 are individually formed of and include tungsten (W). The contact structures 146 may individually be homogeneous, or the contact structures 146 may individually be heterogeneous.
The contact structures 146 may be formed by forming (e.g., non-conformably depositing, such as through one or more of a PVD process and a non-conformal CVD process) conductive material inside and outside of the contact openings 144 (FIGS. 6A and 6B), and then removing (e.g., through an abrasive planarization process, such as a CMP process) portions of the conductive material overlying an uppermost vertical boundary (e.g., an uppermost surface) of the dielectric fill material 124.
Thus, embodiments of the disclosure include a microelectronic device. The microelectronic device includes a stack structure comprising blocks separated from one another by dielectric slot structures and each including a vertically alternating sequence of conductive structures and insulative structures arranged in tiers. At least one of the blocks includes a stadium structure comprising opposing staircase structures each having steps comprising edges of the tiers; and a filled trench vertically overlying and within horizontal boundaries of the stadium structure of the at least one of the blocks. The filled trench includes a dielectric liner material on the opposing staircase structures of the stadium structure and on inner sidewalls of the two bridge regions. The filled trench further includes at least one dielectric structure doped with one or more of carbon and boron on the dielectric liner material, the at least one dielectric structure horizontally overlapping the steps of the stadium structure.
Another embodiment of the disclosure includes a method of forming a microelectronic device. The method includes forming a preliminary stack structure comprising a vertically alternating sequence of sacrificial material and insulative material arranged in preliminary tiers, the preliminary stack structure further comprising at least one stadium structure. The method further includes forming a first dielectric liner material on surfaces of the preliminary stack structure defining at least one trench vertically overlying and within a horizontal area of the at least one stadium structure. The method also includes forming a second dielectric liner material over the first dielectric liner material and within the at least one trench, the second dielectric liner material having a different composition from the first dielectric liner material. The method further includes doping the second dielectric liner material with at least one dopant formulated to reduce an etching rate of the second dielectric liner material relative to the first dielectric liner material, and the sacrificial material. The method also includes forming dielectric fill material over the doped second dielectric liner material and within the at least one trench, having a different material composition than the doped second dielectric liner material. The method further includes replacing the sacrificial material of the preliminary stack structure with conductive material to form a stack structure having tiers each comprising the conductive material and insulative material vertically adjacent the conductive material.
Microelectronic device structures (e.g., the microelectronic device structure 100 previously described with reference to FIGS. 8A and 8B) of the disclosure may be included in microelectronic devices of the disclosure. For example, FIG. 9 illustrates a partial cutaway perspective view of a portion of a microelectronic device 902 (e.g., a memory device, such as a 3D NAND Flash memory device) including a microelectronic device structure 900. The microelectronic device structure 900 may be substantially similar to the microelectronic device structure 100, previously described with reference to FIGS. 8A and 8B. For clarity and ease of understanding the drawings and associated description, some features (e.g., structures, materials) of the microelectronic device structures 100 previously described herein are not shown in FIG. 9. However, it will be understood that any features of the microelectronic device structure 100 previously described with reference to one or more of FIGS. 8A and 8B may be included in the microelectronic device structure 900 of the microelectronic device 902 described herein with reference to FIG. 9.
As shown in FIG. 9, in addition to the features of the microelectronic device structure 900 previously described herein in relation to the microelectronic device structure 100 (FIGS. 8A and 8B), the microelectronic device 902 may further include cell pillar structures 952 vertically extending through each block 930 of the stack structure 932. The cell pillar structures 952 may be positioned within regions (e.g., memory array regions) of the block 930 horizontally offset (e.g., in the X-direction) from the stadium structures 914 (e.g., the first stadium structure 914A) (and, hence, the bridge regions 924 (first bridge region 924A and second bridge region 924B) and the further filled slot structures 950) within the blocks 930. Intersections of the cell pillar structures 952 and the conductive material 934 of the tiers 936 of the stack structure 932 within the horizontal areas of the blocks 930 form strings of memory cells 954 vertically extending through each block 930 of the stack structure 128. For each string of memory cells 954, the memory cells 954 thereof may be coupled in series with one another. Within each block 930, the conductive material 934 of some of the tiers 936 of the stack structure 932 may serve as access line structures (e.g., word line structures) for the strings of memory cells 954 within the horizontal area of the block 930. In some embodiments, within each block 930, the memory cells 954 formed at the intersections of the conductive material 934 of some of the tiers 936 and the cell pillar structures 952 comprise so-called “MONOS” (metal—oxide—nitride—oxide—semiconductor) memory cells. In additional embodiments, the memory cells 954 comprise so-called “TANOS” (tantalum nitride—aluminum oxide—nitride—oxide—semiconductor) memory cells, or so-called “BETANOS” (band/barrier engineered TANOS) memory cells, each of which are subsets of MONOS memory cells. In further embodiments, the memory cells 954 comprise so-called “floating gate” memory cells including floating gates (e.g., metallic floating gates) as charge storage structures. The floating gates may horizontally intervene between central structures of the cell pillar structures 952 and the conductive material 934 of the different tiers 936 of the stack structure 932.
The microelectronic device 902 may further include at least one source structure 960, access line routing structures 964, first select gates 956 (e.g., upper select gates, drain select gates (SGDs)), select line routing structures 966, one or more second select gates 958 (e.g., lower select gates, source select gate (SGSs)), and digit line structures 962. The digit line structures 962 may vertically overlie and be coupled to the cell pillar structures 952 (and, hence, the strings of memory cells 954). The source structure 960 may vertically underlie and be coupled to the cell pillar structures 952 (and, hence, the strings of memory cells 954). In addition, the first contact structures 940A (e.g., select line contact structures) and the second contact structures 940B (e.g., access line contact structures) may couple various features of the microelectronic device 902 to one another as shown (e.g., the select line routing structures 966 to the first select gates 956; the access line routing structures 964 to the conductive materials 934 of the tiers 936 of the stack structure 932 underlying the first select gates 956 and defining access line structures of the microelectronic device 902).
The microelectronic device 902 may also include a base structure 968 positioned vertically below the cell pillar structures 952 (and, hence, the strings of memory cells 954). The base structure 968 may include at least one control logic region including control logic devices configured to control various operations of other features (e.g., the strings of memory cells 954) of the microelectronic device 902. As a non-limiting example, the control logic region of the base structure 968 may further include one or more (e.g., each) of charge pumps (e.g., VCCP charge pumps, VNEGWL charge pumps, DVC2 charge pumps), delay-locked loop (DLL) circuitry (e.g., ring oscillators), Vdd regulators, drivers (e.g., string drivers), page buffers, decoders (e.g., local deck decoders, column decoders, row decoders), sense amplifiers (e.g., equalization (EQ) amplifiers, isolation (ISO) amplifiers, NMOS sense amplifiers (NSAs), PMOS sense amplifiers (PSAs)), repair circuitry (e.g., column repair circuitry, row repair circuitry), I/O devices (e.g., local I/O devices), memory test devices, MUX, error checking and correction (ECC) devices, self-refresh/wear leveling devices, and other chip/deck control circuitry. The control logic region of the base structure 968 may be coupled to the source structure 960, the access line routing structures 964, the select line routing structures 966, and the digit line structures 962. In some embodiments, the control logic region of the base structure 968 includes CMOS (complementary metal-oxide-semiconductor) circuitry. In such embodiments, the control logic region of the base structure 968 may be characterized as having a “CMOS under Array” (“CuA”) configuration.
Thus, embodiments of the disclosure include a memory device. The memory device includes a stack structure comprising tiers each comprising conductive material and insulative material vertically neighboring the conductive material. The memory device further includes a stadium structure comprising staircase structures individually having steps comprising horizontal ends of at least some the tiers of the stack structure. The memory device also includes a dielectric liner material on surfaces of the stadium structure. The memory device further includes dielectric structures on the dielectric liner material and substantially confined within horizontal boundaries of the steps of the stadium structure, the dielectric structures each comprising a dielectric nitride material doped with one or more of carbon and boron. The memory device also includes a dielectric fill material over the dielectric structures and the dielectric liner material. The memory device further includes strings of memory cells vertically extending through a portion of the stack structure horizontally neighboring the stadium structure.
Microelectronic devices structures (e.g., the microelectronic device structure 100 (FIGS. 8A and 8B)) and microelectronic devices (e.g., the microelectronic device 902 (FIG. 9)) of the disclosure may be included in embodiments of electronic systems of the disclosure. For example, FIG. 10 is a block diagram of an electronic system 1000, in accordance with embodiments of the disclosure. The electronic system 1000 may comprise, for example, a computer or computer hardware component, a server or other networking hardware component, a cellular telephone, a digital camera, a personal digital assistant (PDA), portable media (e.g., music) player, a Wi-Fi or cellular-enabled tablet such as, for example, an iPAD® or SURFACE® tablet, an electronic book, a navigation device, etc. The electronic system 1000 includes at least one memory device 1002. The memory device 1002 may include, for example, an embodiment of one or more of a microelectronic device structure (e.g., the microelectronic device structure 100 (FIGS. 8A and 8B)) and microelectronic device (e.g., the microelectronic device 902 (FIG. 9)) previously described herein.
The electronic system 1000 may further include at least one electronic signal processor device 1004 (often referred to as a “microprocessor”). The electronic signal processor device 1004 may, optionally, include an embodiment of one or more of a microelectronic device structure (e.g., the microelectronic device structure 100 (FIGS. 8A and 8B)) and microelectronic device (e.g., the microelectronic device 902 (FIG. 9)) previously described herein. The electronic system 1000 may further include one or more input devices 1006 for inputting information into the electronic system 1000 by a user, such as, for example, a mouse or other pointing device, a keyboard, a touchpad, a button, or a control panel. The electronic system 1000 may further include one or more output devices 1008 for outputting information (e.g., visual or audio output) to a user such as, for example, a monitor, a display, a printer, an audio output jack, a speaker, etc. In some embodiments, the input device 1006 and the output device 1008 may comprise a single touchscreen device that can be used both to input information to the electronic system 1000 and to output visual information to a user. The input device 1006 and the output device 1008 may communicate electrically with one or more of the memory device 1002 and the electronic signal processor device 1004.
Thus, embodiments of the disclosure include an electronic system. The electronic system includes an input device, an output device, a processor device operably coupled to the input device and the output device, and a memory device operably coupled to the processor device and comprising at least one microelectronic device structure. The microelectronic device structure including a stack structure having a vertically alternating sequence of conductive material and insulative material arranged in tiers, the stack structure comprising at least two blocks separated from one another by at least one dielectric structure. Each of the at least two blocks including a stadium structure comprising opposing staircase structures individually having steps comprising horizontal ends of at least some of the tiers of the stack structure. The blocks further including a dielectric liner material on surfaces of the stadium structure. The blocks also including at least one dielectric landing structure on the dielectric liner material and comprising dielectric material doped with one or more of carbon and boron, the at least one dielectric landing structure horizontally overlapping the steps of the opposing staircase structures of the stadium structure. The blocks also including a dielectric fill material over the dielectric structure and the dielectric liner material.
Embodiments of the disclosure may result in improved etch resistance in landing pads formed over the steps of the staircase structure. As described above, improving etch resistance of the landing pads may result in the landing pads covering a larger area of the horizontal portions of the steps of the staircase structure. Larger landing pads may substantially prevent subsequent etching processes, such as etching processes during the process of forming contact structures from bypassing the landing pads. Improved etch resistance may also increase the predictability of the etching processes used to form different elements of an associated microelectronic structure. Increasing the predictability of the etching processes may result in fewer failures due to over etching or under etching. Under etching and/or over etching may result in contacts that do not connect with the correct structures or that connect with more than one structure resulting failure due to shorts or open contacts. Therefore, increasing the predictability of the etching processes may result in fewer failure, which may increase yields and reduce waste when producing the associated microelectronic devices.
The embodiments of the disclosure described above and illustrated in the accompanying drawing figures do not limit the scope of the invention, since these embodiments are merely examples of embodiments of the invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of this disclosure. Indeed, various modifications of the present disclosure, in addition to those shown and described herein, such as alternative useful combinations of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims and their legal equivalents.
Patent Application
20240071919
