Generally, the present invention relates to semiconductor devices. More particularly, the present invention relates to semiconductor devices utilizing a capacitor.
Capacitors which are part of a semiconductor device, such as metal-insulator-metal or MIM capacitors, may require extra processing. An MIM capacitor may be formed as two metal layers with an embedded dielectric layer and this may be processed in addition to the back end of line metal stack. This extra processing may generate extra cost for metal deposition, lithography, and etch. In addition, the quality or Q factor for the capacitor may be low due to high ohmic resistances in the capacitor plates. New methods for making capacitors are needed.
The accompanying drawings are included to provide a further understanding of embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated as they become clear better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other.
The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.
FIGS. 4A,B,C illustrate a semiconductor structure 100 which is an embodiment of a partially completed semiconductor device of the present invention.
While not shown, the chip 200 typically includes a substrate which may be adjacent or proximate to its bottom surface. Likewise, the chip may further include additional metal layers, additional dielectric layers (such as interlevel dielectric layers), components such as diodes and transistors, logic circuits, memory circuits, etc. The final metal layer may be electrically coupled to the chip substrate as well as to devices that are formed in the chip substrate.
The final metal layer 230 of the chip 200 may comprise any metallic material. The final metal layer may be any pure metal or metal alloy. The final metal layer may include one or more elements such as Cu, Al, W, Au, or Ag. In one or more embodiments, the final metal layer may include the element C. Examples of metallic materials which may be used include, but are not limited to, pure copper, copper alloy, pure aluminum, aluminum alloy, pure tungsten, tungsten alloy, pure silver, silver alloy, pure gold, and gold alloy. The final metal layer may be used in combination with additional layers such as barriers, liners and/or cap layers comprising, for example, Ta, TaN, TaC, Ti, TiN, TiW, WN, WCN, CoWP, CoWB, NiMoP, Ru, Ni, Pd or combinations thereof.
The final metal layer may comprise one or more metal lines which may be referred to herein as final metal lines. In one or more embodiments, the final metal layer has at least two final metal lines. In an embodiment, each of the final metal lines of the final metal layer may be spacedly disposed from each other. In an embodiment, each of the final metal lines may be electrically isolated from each other.
In the embodiment shown in FIGS. 1A,B, the final metal layer 230 includes at least a first final metal line 230A, a second final metal line 230B, a third final metal line 210C and a fourth final metal line 230D. In one or more embodiments, at least one of the final metal lines may include one or more bonding pads (also referred to as contact pads). In one or more embodiments, each of the final metal lines may include one or more bonding pads.
Generally, the thickness of the final metal lines is not limited to any particular thickness. In one or more embodiments, each of the final metal lines 230A-D may have a thickness which is greater than about 250 nm (nanometers). In one or more embodiments, each of the final metal lines 230A-D may have a thickness which is greater than about 400 nm. In one or more embodiments, each of the final metal lines 230A-D may have a thickness which is greater than about 500 nm. In one or more embodiments, each of the final metal lines 230A-D may have a thickness which is greater than about 600 nm. In one or more embodiments, each of the final metal lines may have a thickness which is greater than about 1000 nm. While not shown in FIGS. 1A,B, the final metal lines may be electrically coupled to underlying metal lines and to devices that are built within the chip substrate.
The passivation layer 240 of chip 200 may be formed of any dielectric material such as an oxide, a nitride, an oxynitride, an imide or combinations thereof. The passivation layer 240 may, for example, comprise one or more dielectric layers such as an oxide layer, a nitride layer, an oxynitride layer, an imide layer, or combinations thereof. As an example, the passivation layer may comprise an oxide layer overlying a nitride layer. As another example, the passivation layer may comprise a nitride layer overlying an oxide layer. As another example, the passivation layer may comprise a nitride-oxide-nitride stack (that is, a nitride layer overlying an oxide layer overlying another nitride layer) As another example, the passivation layer may comprise an oxide-nitride-oxide stack. In one or more embodiments, it is possible that the passivation layer 240 be formed of a high-K dielectric material. In one or more embodiments, the high-K material may have a dielectric constant greater than that of silicon dioxide. In one or more embodiments, the high-K material may have a dielectric constant greater than 3.9.
In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be less than about 1000 nm (nanometer). In one or more embodiments, the thickness of the oxide layer and/or nitride layer may be less than about 500 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be less than about 250 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be less than about 200 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be less than about 150 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be less than about 100 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be less than about 50 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be less than about 25 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be greater than about 15 nm. In one or more embodiments, the thickness of the oxide layer and/or the thickness of the nitride layer may be greater than about 30 nm.
In one or more embodiments, the thickness of the passivation layer 240 may be less than about 1000 nm. In one or more embodiments, the thickness of the passivation layer 240 may be less than about 500 nm. In one or more embodiments, the thickness of the passivation layer 240 may be less than about 250 nm. In one or more embodiments, the thickness of the passivation layer 240 may be less than about 150 nm. In one or more embodiments, the thickness of the passivation layer 240 may be less than about 100 nm. In one or more embodiments, the thickness of the passivation layer 240 may be less than about 50 nm. In one or more embodiments, the thickness of the passivation layer 240 may be less than about 25 nm.
In the embodiment of the chip 200 shown in FIGS. 1A,B, openings 250A and 250B are formed through the passivation layer 240 so as to expose the second final metal lines 230A and 230B, respectively, of the final metal layer 230. The openings 250A and 250B may each be in the form of a hole and may be referred to as via openings. The openings 250A and 250B provide for future electrical coupling of the first final metal line 230A and the second final metal line 230B to, for example, redistribution layers. The openings 250A and 250B may be formed by a wet etch process or a dry etch process.
The plate assembly 300 further includes a conductive layer 320 that may be disposed over the base 310. The conductive layer 320 may be formed from any conductive material. The conductive material may be a metallic material such as a pure metal or a metal alloy. For example, the conductive layer 320 may include one or more of the elements Cu, Al, W, Au, or Ag. The conductive layer 320 may be formed of pure copper, copper alloy, pure aluminum, aluminum alloy, pure tungsten, tungsten alloy, pure silver, silver alloy, pure gold or gold alloy. The conductive material may be non-metallic. For example, the conductive material may be a doped polysilicon. The conductive material may be a conductive polymer. In an embodiment, the conductive layer 320 may consist essentially of a metallic material.
The conductive layer 320 may be formed, for example, by one or more of the techniques such as sputtering, plating, evaporation, CVD, atomic layer deposition followed by patterning (which may be lithography plus etching) steps or alternatively patterned plating or any damascene technology. The conductive layer 320 serves as a lower conductive plate for a capacitor. It is noted that as used herein, the term “plate” may have any shape and does not have to be flat. In one embodiment, a plate may be substantially flat.
In another embodiment, it is possible that a barrier material be placed between the conductive layer 320 and the base 310. The barrier material may include one or more of the materials Ta, TaN, Ti, TiN, TiW, WN, WCN.
The plate assembly 300 further includes a dielectric layer 330 disposed over the conductive interconnect 320. The dielectric layer 330 serves as the capacitor dielectric. The dielectric layer 330 may be any dielectric material. For example, the dielectric material 330 may be an oxide (such as silicon oxide), a nitride (such as silicon nitride), an oxynitride, an imide, a polyimide, a photoimide, a BCB (Benzo-cyclo-butene), etc. The dielectric layer 330 may include a high-k material such as Al2O3, Ta2O5, HfO2, HfxSiyOz ZrO2, TiO2 Nb2O5, TiTaO, TiSiO4, TaZrO BST, STO or PZT. The dielectric layer 330 may be a combination of different dielectric materials. The dielectric layer may be a laminated layer stack such as Al2O3/HfO2/Al2O3, Al2O3/Ta2O5/Al2O3, HfO2/Ta2O5/HfO2 or other combinations.
After the dielectric layer 330 is formed, a protective layer 340 may be formed over the dielectric layer 330. The protective layer 340 may be formed of any dielectric material. For example, the protective layer may be formed of an oxide, a nitride an oxynitride, a imide, a polyimide, a photoimide , a BCB, an epoxy or any other dielectric polymer material. Alternately, it is possible to use a thicker dielectric layer as both the capacitor dielectric and a protective layer (for example, a lower portion used as the capacitor dielectric and an upper portion used as a protective layer).
A first opening 350A may then be formed through the protective layer 340 to expose the dielectric layer 330. The first opening 350A may stop on or within the dielectric layer 330. A second opening 350B is formed through the protective layer 340 and through dielectric layer 330 so as to expose the conductive layer 320. The second opening 350B may be formed on or within the conductive layer 320. First opening 350A is spacedly disposed from the second opening 350B. In one or more embodiments, each of the openings 350A,B may be in the formed of a hole. The openings 350A,B provide for the possibility of electrically coupling a conductive redistribution layer to either the dielectric layer 330 (e.g. the capacitor dielectric) and/or to the conductive layer 320 (e.g. the capacitor plate).
In the embodiment shown in
In one or more embodiments, the chip and/or the plate assembly may be at least partially embedded within the support. In one or more embodiments, the chip and/or the plate assembly may be partially embedded within the support. In one or more embodiments, the chip and/or the plate assembly may be totally embedded within the support.
In the embodiment shown in FIGS. 4A,B,C, the plate assembly 300 is laterally spacedly disposed (e.g., spacedly displaced) from the chip 200 such that there is some lateral distance or space between the plate assembly 300 and the chip 200. However, in another embodiment, it is possible that the plate assembly 300 be simply laterally disposed from the chip 200 which would thus include the possibility that the plate assembly may touch or abut the chip 200.
FIGS. 1A,B show a single semiconductor chip 200, however, a plurality of semiconductor chips 200 may be formed at the same time on a single semiconductor wafer. The semiconductor wafer may then be singulated or diced into individual or singulated semiconductor chips 200. Singulation or dicing may be done with, for example, a diamond saw or a laser (or by any other method such as a chemical method). Likewise,
After forming a plurality of individual semiconductor chips (such as shown in FIGS. 1A,B) and a plurality of individual plate assemblies (such as shown in
In one or more embodiments, there may be a one to one ratio of chips and plate assemblies. In one or more embodiments, there may be more than one plate assembly per chip. In one or more embodiments, there may be more than one chip per plate assembly.
The pre-assembly process may be accomplished by placing the chips onto the surface of a carrier using a double sided adhesive tape. Next, one or more of the plate assemblies 300 may be positioned with their top surfaces (e.g., the surface having openings 350A,B) facing down on the carrier in the neighborhood of each of the chips also with the use of the tape. In one or more embodiments, one or more of the plate assemblies 300 may be placed adjacent to or proximate to a corresponding semiconductor chip 200. In one or more embodiments, the plate assemblies are spacedly disposed from the chips. In one or more embodiments, it is possible that the plate assemblies may touch the chips.
Hence, in one or more embodiments of the invention, the chips and the plate assemblies may be placed face down onto the tape. For example, the openings 250A and 250B of the chip 200 as well as the openings 350A and 250B of the plate assembly face toward the tape. The chip bottom and assembly bottom point away from the tape.
After placing the semiconductor chips 200 and the corresponding plate assemblies 300 onto a tape, the chips and assemblies are at least partially embedded within a support structure. This may be done in various ways. For example, the tape, the chips and the plate assemblies may be placed within a molding chamber, which is then filled with a liquid molding compound. In one or more embodiments, the molding compound may comprise a dielectric material. In one or more embodiments, the molding compound may consist essentially of a dielectric material. In one or more embodiments, the molding compound may comprise one or more of a variety of materials such as a plastic, polyimide, an epoxy based material or a BCB (Benzo-cyclo-butene). In one or more embodiments, the molding compound may have a low coefficient of thermal expansion (CTE) or a CTE that matches that of the semiconductor chip (which may comprise a silicon material). The molding compound fills in the spaces between the chips and the assemblies and may additionally be poured to a level which is above the bottom surfaces of the chips and/or the bottom surfaces of the plate assemblies.
After a molding compound has been used, an application of heat and/or pressure may then be used to harden the resin and build a planar assembly of a molded wafer with the embedded chips and plate assemblies. The molded wafer may then be removed from the carrier plate and the tape may be peeled away from the molded reconfigured wafer. The molding compound forms the support structure (also referred to as the support substrate or the support) for the reconfigured wafer.
In one or more embodiments, the molding compound may contact the side surfaces and the bottom surfaces of the chips and the plate assemblies without contacting the top surfaces. After the tape is removed, the top surfaces of the semiconductor chips and the plate assemblies are revealed to be exposed through the top surface of the support substrate.
In another embodiment, it is possible that the molding compound is only formed about the side surfaces of the chips and/or plate assemblies without contacting either the top or bottom surfaces. Also, in another embodiment it is possible that the molding compound is formed over at least a portion of the top surfaces of the chips and/or the plate assemblies.
FIGS. 4A,B,C show top and cross sectional views of a structure 100 that includes a semiconductor chip 200 and an plate assembly 300 embedded or disposed within a support structure 410.
Referring to FIGS. 4A,B,C it is seen that the lateral boundary of the structure 100 extend beyond the lateral boundary of the chip 200. The portion of structure 100 that is laterally outside the lateral boundary of the chip 200 is the fan-out region of the structure 100.
From
In the embodiment shown in
Referring to FIGS. 5A,B,C (with
In an embodiment, a redistribution layer may be a single continuous conductive layer. In another embodiment, a redistribution layer may include a plurality of conductive portions. In an embodiment, two or more of the conductive portions may be spacedly disposed from each another. In an embodiment, two or more of the conductive portions may be electrically isolated from one another.
In one or more embodiments, each conductive portion of the redistribution layer may be a conductive layer which may form a conductive pathway. A conductive portion of the redistribution layer may have any shape. For example, it may be straight or curved. It may be star shaped (for example, fingers radiating from a central location). In one or more embodiments, the conductive portions of a redistribution layer may be conductive traces.
Generally, the redistribution layer may be formed of any conductive material. In one or more embodiments, the redistribution layer may comprise a metallic material. The metallic material may be a pure metal or a metal alloy. The metallic material may include one or more of the elements Cu, Al, W, Ag or Au. In one or more embodiments, the metallic material may comprise the element C (carbon). Examples of materials include, but are not limited to, metallic copper, copper alloy, metallic aluminum, and aluminum alloy. In an embodiment, the redistribution layer may consist essentially of a metallic material. In an embodiment, it is possible that the redistribution layer be formed by a metallic plating process.
In one or more embodiments, the redistribution layer may be formed of a non-metallic material such as a doped polysilicon or a conductive polymer. In one or more embodiments, the redistribution layer may, for example, be at least 1 μm (micron) thick and/or at least 1 μm (micron) wide. In one or more embodiments, the redistribution layer may, for example, be at least 2 microns thick and/or at least 2 microns wide.
The redistribution layer may, for example, be useful in distributing electrical signals to various portions of the semiconductor wafer, structure or device. The electrical signals may be in the form of electrical currents or voltages. In one or more embodiments, the redistribution layer may redistribute electrical signals to other positions that overlie the semiconductor chip. In one or more embodiments, the redistribution layer may redistribute electrical signals to positions that extend beyond the lateral boundaries of the chip. Hence, the redistribution layer may redistribute electrical signals to the fan-out region of the wafer, structure or device. Hence, in one or more embodiments, at least a portion of the redistribution layer may extend into the fan-out region of the wafer, structure or device.
In one or more embodiments of the invention, conductive balls (such as metallic balls or solder balls) may be electrically coupled to the conductive portions (such as to ends or termination points of the conductive portions). The conductive balls may be used to electrically couple the structure to, for example, a printed circuit board or a BGA-substrate. In one or more embodiments, the resulting wafer, structures or semiconductor devices may be formed as a wafer level ball package.
Referring again to FIGS. 5A,B,C, the redistribution layer 500 includes a first conductive portion 500A and a second conductive portion 500B. First conductive portion 500A and second conductive portion 500B are spacedly disposed from each other.
Referring to
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Referring to
Referring to
Generally, the conductive layer 320 as well as the redistribution layer may be formed of any conductive material. In one or more embodiments, the conductive layer 320 as well as the first portion 500A of the redistribution layer may both consist essentially of a metallic material. In this case, both the lower and upper capacitor plate consist essentially of a metallic material. In this case, the capacitor may be an MIM (metal-insulator-metal) capacitor. The metallic material may, for example, be a pure metal or a metal alloy. One or more additional layers may, of course, be disposed between the conductive portion 500A and the dielectric layer 330, between the dielectric layer 330 and the conductive layer 320, or between the conductive layer 320 and the conductive portion 500B.
The
Hence, after the reconfigured wafer is formed (such as by a molding process), a protective dielectric layer 600 (for example, an oxide, a nitride, an oxynitride, a polyimide, a BCB, etc.) may be deposited over the structure. Hence, the protective dielectric layer 600 may be formed over the semiconductor chip 200, the plate assembly 300′ and the support 410. Referring to
Referring to
Referring to
It is noted that in one or more embodiments, the plate assembly may be formed without the use of a base. For example, referring to
It is also noted that in one or more embodiments, the plate assembly may be formed without the use of a capacitor dielectric layer. For example, the plate assembly may simply consist essentially of a lower capacitor plate. In such a case, the lower capacitor plate may be at least partially embedded within the support (for example, when the molding compound is used). A capacitor dielectric may later be formed over the lower capacitor plate to form a capacitor dielectric. The capacitor dielectric may be formed after the reconfiguration wafer is formed. A conductive layer such as a reconfiguration layer may then be formed over the capacitor dielectric to form an upper or top capacitor plate. In yet another embodiment, the plate assembly may consist essentially of a capacitor plate disposed over a base.
In yet another embodiment, it is also possible that a plurality of chips be at least partially embedded within a support to form a reconfiguration wafer. The capacitor may then be formed after the reconfiguration wafer is formed. Hence, it is possible that a first (e.g., lower or bottom) capacitor plate, a capacitor dielectric as well as a second (e.g. upper or top) capacitor plate be formed after the reconfiguration wafer is formed.
In one or more embodiments, in a downstream processing step, after the individual structures on a reconfigured wafer are completed, the wafer may be singulated to form individual and separated semiconductor devices. The singulation process may be performed, for example, by mechanical means such as with the use of a saw, thermal means such as with the use of a laser, by chemical means or by any other means.
An embodiment of the invention is a semiconductor structure, comprising: a semiconductor chip at least partially embedded within a support; and a capacitor electrically coupled to the chip, the capacitor disposed outside the lateral boundary of the chip.
An embodiment of the invention is a semiconductor structure, comprising: a semiconductor chip at least partially embedded within a support; a first conductive layer at least partially embedded within the support outside the lateral boundary of the chip, the first conductive layer being electrically coupled to the chip; a second conductive layer electrically coupled to the chip, at least a portion of second conductive layer disposed over the first conductive layer; and a dielectric material between the first conductive layer and second conductive layer.
An embodiment of the invention is a method of forming a semiconductor structure, comprising: providing a wafer, the wafer comprising at least two semiconductor chips; dicing the wafer into individual chips; and forming a structure by a method comprising the step of at least partially embedding a plurality of the individual chips in a support, the structure including a plurality of capacitors, each of the capacitors at least partially embedded within the support outside the lateral boundaries of the chips, the capacitors being electrically coupled to the chips.
An embodiment of the invention is a method of forming a semiconductor structure, comprising: dicing a wafer into at least two individual chips; at least partially embedding a plurality of the chips in a support; and forming a plurality of capacitors, each of the capacitors being at least partially embedded within the support outside the lateral boundaries of the chips.
An embodiment of the invention is a method of forming a semiconductor structure, comprising: dicing a wafer into at least two individual chips; providing a plurality of individual conductive plates; at least partially embedding a plurality of the chips in a support; at least partially embedded a plurality of the plates in a support, the plates being disposed outside the lateral boundaries of the chips; forming a dielectric material over each of the plates; and forming a redistribution layer, at least a portion of the redistribution layer formed over the dielectric material.
It is to be understood that the disclosure set forth herein is presented in the form of detailed embodiments described for the purpose of making a full and complete disclosure of the present invention, and that such details are not to be interpreted as limiting the true scope of this invention as set forth and defined in the appended claims.