The disclosure relates to a method for filling a gap without forming a void in the gap, and more specifically to a method for controlling a forming a film at the upper portion of the gap to fill the gap more effectively without forming a void therein.
In gap fill process to a semiconductor device, the profile of the gap structure is an important process factor for effective gap fill process. For instance, a gap structure with low aspect ratio or positive slope may be filled easily without forming a void in it.
As the line width of the circuit of the semiconductor device becomes narrower, an atomic layer deposition (ALD) method was introduced as a gap fill process. The ALD method may facilitate a precise control of the film thickness. However, a fast gas exchange in ALD method may result in different film growth rate between an upper portion and a lower portion of the gap, leading to an overhang in the upper portion and a void formation inside of the gap.
To address the cracks and deterioration, an inhibitor such as N2 was introduced. The inhibitor may suppress a film from being formed in the upper portion of the gap and lower a film growth rate thereon, so a gap fill process may be more facilitated.
In
In one or more embodiments, a gap fill process may be carried out by plasma enhanced atomic layer deposition. In more detail, the gap fill process may include a step of forming a film and a step of inhibiting.
In one or more embodiments, the step of forming the film on the substrate may comprise a step of supplying a source gas and a step of supplying a reactant gas sequentially and alternately.
In one or more embodiments, in the step of supplying a source gas and the step of supplying a reactant gas, the source gas may contain silicon and the reactant may contain oxygen.
In one or more embodiments, the step of inhibiting may comprise a step of supplying inhibitors to the substrate and a step of activating the inhibitors.
In one or more embodiments, the step of supplying inhibitors may comprise supplying a first inhibitor and supplying a second inhibitor.
In one or more embodiments, the first inhibitor may comprise a nitrogen-containing gas and the second inhibitor may comprise a hydrogen-containing gas.
In one or more embodiments, supplying the first inhibitor and supplying the second inhibitor may be carried out sequentially and alternately.
In one or more embodiments, the reactant and the inhibitor may be activated by applying a RF power to the reactor. The RF power to activate the reactant may be high frequency RF power and the RF power to activate the inhibitors may be low frequency RF power.
In one or more embodiments, the gap fill process may comprise a super cycle comprising the step of forming the film and the step of inhibiting, wherein the step of forming the film may be repeated more than one time and the step of inhibiting may be repeated more than one time, and the super cycle is repeated more than one time.
In one or more embodiments, at least a portion the gap may have a negative slope or a complex structure such as non-straight profile structure.
This summary is provided to introduce a selection of concepts in a simplified form. These concepts are described in further detail in the detailed description of example embodiments of the disclosure below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of illustrated embodiments of the present disclosure.
Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the invention extends beyond the specifically disclosed embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the invention disclosed should not be limited by the particular disclosed embodiments described below.
As used herein, the term “substrate” may refer to any underlying material or materials, including any underlying material or materials that may be modified, or upon which, a device, a circuit, or a film may be formed. The “substrate” may be continuous or non-continuous; rigid or flexible; solid or porous; and combinations thereof. The substrate may be in any form, such as a powder, a plate, or a workpiece. Substrates in the form of a plate may include wafers in various shapes and sizes. Substrates may be made from semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride and silicon carbide.
A continuous substrate may extend beyond the bounds of a process chamber where a deposition process occurs. In some processes, the continuous substrate may move through the process chamber such that the process continues until the end of the substrate is reached. A continuous substrate may be supplied from a continuous substrate feeding system to allow for manufacture and output of the continuous substrate in any appropriate form.
Non-limiting examples of a continuous substrate may include a sheet, a non-woven film, a roll, a foil, a web, a flexible material, a bundle of continuous filaments or fibers (for example, ceramic fibers or polymer fibers). Continuous substrates may also comprise carriers or sheets upon which non-continuous substrates are mounted.
The illustrations presented herein are not meant to be actual views of any particular material, structure, or device, but are merely idealized representations that are used to describe embodiments of the disclosure.
The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationship or physical connections may be present in the practical system, and/or may be absent in some embodiments.
It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various acts illustrated may be performed in the sequence illustrated, in other sequences, or omitted in some cases.
The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems, and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.
The disclosure provides a method for suppressing a film from being formed in the upper portion of the gap more effectively in filling a gap, more specifically in a gap with high aspect ratio or in a gap which may have a negative slope in at least a portion of the gap structure.
Each step of
A step of loading a substrate 100: In the step 100, a substrate may be loaded onto a substrate support unit of the reactor (not shown). The substrate may comprise a gap including a trench. The substrate support unit may comprise a susceptor mounted thereon and the substrate may be loaded onto the susceptor. The substrate support unit may further comprise a heating block. The heating block may heat the substrate to a set temperature. The substrate support unit itself may be the heating block such that the susceptor may be omitted and the substrate may be loaded onto the heating block directly. The reactor may comprise a gas supply unit and a substrate support unit facing the gas supply unit. At least one of the gas supply unit and the substrate support unit may be connected to an RF power generator and act as an electrode. In this case, the gas supply unit may be referred to as an upper electrode and the substrate support unit may be referred to as a lower electrode. The upper electrode and the lower electrode may form a reaction space formed therebetween.
A step of suppling a source gas and a reactant 200: In the step 200, a source gas and a reactant may be supplied to the substrate loaded to the reactor. The source gas and the reactant may be supplied simultaneously, but not react chemically each other. But in the next step 300 as described later the activated reactant may react chemically with the source gas and form a compound on the substrate. Therefore, in the step 200 the reactant may act as a reactive purge gas. The source gas supplied may be adsorbed on the substrate. In another embodiment, the source gas and the reactant may be supplied sequentially and alternately, not supplying simultaneously. The source gas may comprise a silicon-containing precursor and the reactant may comprise an oxygen-containing precursor.
A step of activating a reactant 300: In the step 300, a reactant may be continuously supplied to the reaction space and activated by applying an energy to at least one of the upper electrode and the lower electrode forming the reaction space. The applied energy may be from at least one of direct plasma, remote plasma, neutral beam, UV and any other external energy source corresponding to them. The activated reactant may react chemically with the source gas adsorbed on the substrate and form a compound thereon. In an embodiment, the compound formed on the substrate may be an insulating film, e.g. silicon oxide (SiO2). The step of supplying a reactant and a reactant 200 and a step of activating a reactant 300 may be referred to as a step of forming a film.
A step of supplying inhibitors 400 and a step of activating the inhibitors 500: In the steps 400 and 500, the inhibitors may be supplied continuously to the substrate and activated. To activate the inhibitors, at least one of direct plasma, remote plasma, neutral beam, UV and any other external energy source may be applied to the reactor. The activated inhibitors may remove the reaction activation sites (e.g. hydroxyl groups such as OH—), from the surface of the compound formed on the substrate. The step of supplying inhibitors 400 and the step of activating the inhibitors 500 may be referred to as a step of inhibiting.
The aforementioned reaction activation sites may react with the source gas supplied during the next cycle and enable a film to be formed and grow. For instance, the activated oxygen gas may be supplied to the silicon source gas adsorbed on the substrate and a silicon oxide film may be formed. During formation of a silicon oxide film, the reaction activation sites (e.g. hydroxyl groups such as OH—) may be formed on the surface of the silicon oxide film. The reaction activation sites may react chemically with the silicon source gas supplied in the next cycle, form a silicon-oxygen-silicon (Si—O—Si) bonding bridge structure and promote the film to continue to grow.
The inhibitors may react with the hydrogen comprising the reaction activation sites and inhibit the film from being formed thereon. In the disclosure, a plurality of inhibitors, for instance, at least more than two inhibitors may be supplied to further enhance the capabilities to remove the reaction activation sites and inhibit the formation of the film. In an embodiment of the disclosure, to further facilitate removing the hydroxyl groups (OH—) from the surface of the silicon oxide film, a nitrogen-containing gas as a first inhibitor and a hydrogen-containing gas as a second inhibitor may be supplied.
In
A step of filling a gap 600 and 700: The step of supplying a source gas and a reactant 200, a step of activating the reactant 300, a step of supplying the inhibitors 400 and a step of activating the inhibitors 500 may be carried out and the gap may be filled with the film 600. If the gap is fully filled with the film, the gap fill process may end 700. If the gap is not filled with the film, the step of supplying a source gas and a reactant 200, a step of activating the reactant 300, a step of supplying inhibitors 400 and a step of activating the inhibitors 500 may be repeated a plurality of times (e.g. M times).
The gap fill process according to
A step of forming a film (t1 to t3): In the steps t1 to t3, a source gas and a reactant may be supplied sequentially and alternately, and a film may be formed on the gap structure. The source gas may comprise a silicon-containing precursor and the reactant may comprise a oxygen-containing precursor, and the film formed on the gap structure may be a silicon oxide (SiO2). The reactant may be activated by RF power applied to the reactor and react chemically with the source gas adsorbed on the substrate in order to form the film. After supplying the source gas and the reactant, a purge step (t2, t4) may be further provided to remove a residual gas from the reactor.
In an embodiment, a high frequency RF power (HRF) and a low frequency RF power (LRF) may be applied together to activate the reactant. The HRF may increase the amount of ions and radicals and the LRF may facilitate ions and radicals to travel to the lower portion of the gap. In an embodiment according to the disclosure, the range of frequency of HRF may be 10 MHz to 100 MHz, more specifically 30 MHz to 60 MHz, and the range of frequency of LRF may be 100 kHz to 800 kHz, more specifically 300 kHz to 500 kHz.
A step of supplying inhibitors (t4 to t6): In the steps t4 to t6, a plurality of inhibitors may be supplied to the film formed on the gap structure. In an embodiment of the disclosure according to
To form more inhibiting area in the upper portion of the gap than in the lower portion of the gap, inhibitors may be activated by applying a high frequency RF power (HRF). Active species such as ions and radicals activated by HRF may have a short mean free path, therefore, inhibitors activated by HRF may react with the source gas adsorbed on the upper portion of the gap more than in the lower portion of the gap. In an embodiment, the frequency of RF power applied in the steps of activating inhibitors may be higher than 13 MHz, more specifically 30 MHz to 60 MHz.
An only nitrogen-containing gas (e.g. N2) is supplied as a single inhibitor in the existing gap fill process, but in an embodiment according to the disclosure a hydrogen-containing gas as well as a nitrogen-containing gas may be supplied as inhibitors to improve much more the inhibiting characteristics. The reaction mechanism occurring when supplying a plurality of inhibitors will be described in more detail later.
The gap may be filled with the film by repeating the step of forming a film (t1 to t3) and the step of supplying inhibitors (t4 to t6) a plurality of times (M times). In an embodiment according to
In another embodiment of
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Table 1 shows a type of nitrogen-containing radicals which may be generated in
In
Table 2 shows a substrate processing conditions for an embodiment of the disclosure.
A silicon-containing source for processing a substrate according to an embodiment of the disclosure and Table 2 may be at least one of TSA, (SiH3)3N; DSO, (SiH3)2; DSMA, (SiH3)2NMe; DSEA, (SiH3)2NEt; DSIPA, (SiH3)2N(iPr); DSTBA, (SiH3)2N(tBu); DEAS, SiH3NEt2; DTBAS, SiH3N(tBu)2; BDEAS, SiH2(NEt2)2; BDMAS, SiH2(NMe2)2; BTBAS, SiH2(NHtBu)2; BITS, SiH2(NHSiMe3)2; DIPAS, SiH3N(iPr)2; TEOS, Si(OEt)4; SiCl4; HCD, Si2C16; 3DMAS, SiH(N(Me)2)3; BEMAS, SiH2[N(Et)(Me)]2; AHEAD, Si2(NHEt)6; TEAS, Si(NHEt)4; Si3H8; DCS, SiH2Cl2; SiHI3; SiH2I2; or a mixture thereof.
An oxygen-containing gas for processing a substrate according to an embodiment of the disclosure and Table 2 may be at least one of O2, O3, CO2, H2O, NO2, N2O, radicals thereof, or a mixture thereof.
A nitrogen-containing gas as an inhibitor for processing a substrate according to an embodiment of the disclosure and Table 2 may be at least one of N2, N2O, NO2, NH3, N2H2, N2H4, radicals thereof, or a mixture thereof.
A hydrogen-containing gas as an inhibitor for processing a substrate according to an embodiment of the disclosure and Table 2 may be at least one of H2, monoatomic hydrogen (H), radicals thereof, or a mixture thereof.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.
This application claims priority to U.S. Provisional Patent Application Ser. No. 63/419,949 filed Oct. 27, 2022 and titled SUBSTRATE PROCESSING METHOD, the disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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63419949 | Oct 2022 | US |