Liquid-phase conformal silicon oxide spin-on deposition

Abstract

A method of liquid phase conformal silicon oxide spin-on deposition includes providing a substrate in a process chamber; spinning a first reactant containing aluminum in a first liquid onto the substrate to form a self-limiting layer of the first reactant on the substrate; spinning a second reactant containing a silanol reagent in a second liquid onto the substrate, where the self-limiting layer of the first reactant catalyzes adsorption of the silanol reagent on the substrate; and thermally treating the substrate to form a silicon oxide film from the adsorbed silanol reagent.

Description

[Technical Field]

[0001] Cross-references to related patents and applications This application claims priority to and the benefit of the filing date of U.S. Provisional Patent Application No. 63 / 147,028, filed February 8, 2021, the entirety of which is incorporated herein by reference.

[0002] The present invention relates generally to a method for depositing conformal oxide on a substrate for a semiconductor device, and more particularly to a method for depositing a silicon oxide film on a substrate by conformal liquid phase spin-on deposition. [Background technology]

[0003] Multi-patterning and self-aligned patterning methods are used throughout the semiconductor industry. Oxide layers are frequently used as sidewall spacers in the patterning process, and the need for high-throughput, low-cost conformal oxide layers continues to grow. Summary of the Invention [Means for solving the problem]

[0004] Embodiments of the present invention describe a processing system and method for liquid-phase conformal silicon oxide spin-on deposition. According to one embodiment, the method includes providing a substrate in a process chamber, spinning a first reactant containing aluminum in a first liquid on the substrate to form a self-limiting layer of the first reactant on the substrate, spinning a second reactant containing a silanol reagent in a second liquid on the substrate, where the self-limiting layer of the first reactant catalyzes adsorption of the second reactant on the substrate, and thermally treating the substrate to form a silicon oxide film from the adsorbed silanol reagent. [Brief explanation of the drawings]

[0005] [Figure 1]FIG. 1 is a process flow diagram for processing a substrate according to an embodiment of the present invention. [Figures 2A-2F] 1A-1C illustrate, in cross-sectional views, a method of forming sidewall spacers on raised features according to an embodiment of the present invention. [Figure 3] 1 illustrates a schematic representation of a processing system for processing a substrate, according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0006] Embodiments of the present invention provide a processing system and method for liquid phase conformal silicon oxide spin-on deposition.

[0007] FIG. 1 is a process flow diagram for processing a substrate, according to an embodiment of the present invention. In step 100, the method includes providing a substrate in a process chamber of a processing system. An exemplary processing system is shown schematically in FIG. 3. The processing system may be configured to process 200 mm substrates, 300 mm substrates, or larger sized substrates. Indeed, as will be appreciated by those skilled in the art, it is contemplated that the processing system may be configured to process substrates, wafers, or LCDs regardless of their size. Accordingly, although aspects of embodiments of the present invention are described in connection with processing semiconductor substrates, the present invention is not so limited.

[0008] In step 102, the method includes spinning an aluminum-containing first reactant in a first liquid onto the substrate. The aluminum-containing first reactant can include, for example, an aluminum salt, an organometallic aluminum compound without a direct aluminum-carbon bond, or an organometallic aluminum compound with a direct aluminum-carbon bond. Examples of aluminum salts include aluminum sulfate (Al2(SO4)3), aluminum bromide (AlBr3), aluminum chloride (AlCl3), aluminum iodide (AlI3), and aluminum hydroxide hydrate (Al(OH)3xH2O). Examples of organometallic aluminum compounds include aluminum β-diketonates, aluminum alkoxides, aluminum dialkylamides, and aluminum phosphine complexes. Examples of aluminum β-diketonates include aluminum tris(acetylacetonate) (Al(acac)3) and aluminum tris(hexafluoroacetylacetonate) (Al(hfac)3). Examples of aluminum alkoxides include aluminum isopropoxide (Al(Oi-Pr)3), where i-Pr is an isopropyl group, and aluminum tert-butoxide (Al(Ot-Bu)3), where t-Bu is a tert-butoxide group. Examples of aluminum dialkylamides include tris(dimethylamino)aluminum ((MeN)3Al) and tris(diethylamino)aluminum ((EtN)3Al). An example of an aluminum phosphine complex includes aluminum phosphide (AlP). Examples of organometallic aluminum compounds include trimethylaluminum ((Al3Me6)) and triethylaluminum (Al2Et6).

[0009] The first liquid may include an organic compound that readily dissolves the first reactant and facilitates transport of the first reactant to the substrate within the process chamber. Non-limiting examples of the first liquid include octane and pyridine. Step 102 may be performed using a liquid dispensing nozzle positioned above the top surface of the rotating substrate. Upon contacting the substrate, a self-limiting layer of the first reactant or a reaction product of the first reactant forms on the substrate, and excess first reactant within the first liquid is shaken off the substrate.

[0010] In step 104, the substrate is optionally rinsed with a rinse solution. The substrate may be spun during the rinse, which may help remove excess first reactant and reaction by-products from the substrate. Non-limiting examples of rinse solutions include octane, isooctane, pyridine, toluene, glycols, ketones, ethers, alcohols, or xylene.

[0011] In step 106, the method includes spinning a second reactant containing a silanol reagent in a second liquid onto the substrate, where a self-limiting layer of the aluminum-containing first reactant catalyzes adsorption of the silanol reagent on the substrate. The second reactant containing the silanol reagent can include an alkoxysilanol, such as tris(tert-butoxy)silanol, tris(tert-pentoxy)silanol, methyl-bis(tert-butoxy)silanol, or methyl-bis(tert-pentoxy)silanol.

[0012] The second liquid may include an organic compound that readily dissolves the second reactant and facilitates transport of the second reactant to the substrate within the process chamber. Non-limiting examples of second liquids include octane and pyridine. Step 106 may be performed using a liquid dispensing nozzle positioned above the top surface of the rotating substrate. Upon contact with the substrate, a layer of the second reactant or a reaction product of the second reactant forms on the substrate, dissolving excess ions in the second liquid. 2 reactants are shaken off the substrate.

[0013] In one example, a first reactant containing trimethylaluminum (TMA) is spun onto a substrate containing Si—OH surface species, after which a second reactant containing tris(tert-pentoxy)silanol (TPSOL) is spun onto the substrate, which reacts with the adsorbed Al-containing catalyst to form CH 10The adsorbed Al-containing catalyst reacts with multiple TPSOL molecules before the Al-containing catalyst is sequestered and catalytic activity ceases. No TPSOL is then added to the substrate.

[0014] In step 108, the substrate is optionally rinsed with a rinse solution. The substrate may be spun during the rinse, which may help remove excess second reactant and reaction by-products from the substrate. Non-limiting examples of rinse solutions include octane and pyridine.

[0015] The sequence of steps 102-108 may be repeated at least once to increase the surface coverage of the first reactant and the second reactant on the substrate, as indicated generally by process arrow 110. According to one embodiment, one or more of spinning the first reactant onto the substrate, spinning the second reactant onto the substrate, and the thermal treatment are performed under a substantially moisture-free inert atmosphere.

[0016] In step 112, the substrate is thermally treated to form a silicon oxide film from the adsorbed or partially reacted silanol reagents. The thermal treatment may be performed by increasing the substrate temperature above the temperature of steps 102-108, or may be performed at a substrate temperature high enough to drive off any remaining liquid from the substrate and react with the adsorbed silanol reagents to form a silicon oxide film. In some examples, the thermal treatment may include baking the substrate at a temperature between about 80°C and about 200°C, or between about 100°C and about 150°C. The chemical composition of the resulting silicon oxide film is SiO x where x is 2 or less.

[0017] The sequence of steps 102-112 may be repeated at least once to increase the thickness of the silicon oxide film, as indicated diagrammatically by process arrow 114.

[0018] According to one embodiment, a substrate includes a first exposed material surface and a second exposed material surface, and spinning a first reactant containing aluminum in a first liquid on the substrate selectively forms a self-limiting layer of the first reactant on the first exposed material surface but not on the second exposed material surface. Then, spinning a second reactant containing a silanol reagent in a second liquid on the substrate, the self-limiting layer of the first reactant catalyzes the selective adsorption of the silanol reagent on the first exposed surface but not on the second exposed surface. A subsequent thermal treatment step selectively forms a high-quality, low-contamination silicon oxide film only on the first exposed surface.

[0019] In some examples, the first exposed material surface may include a dielectric material surface, such as SiO2, a high-k material, or a low-k material. For example, the high-k material may include a metal oxide, such as Al2O3 or HfO2. For example, the low-k material may include a SiCOH material. In one example, the second exposed material surface may include a metal surface, such as Cu, Ru, Co, or W. According to one embodiment, the substrate includes patterned features, and the silicon oxide film is conformally deposited over the patterned features with at least a substantially constant thickness. The patterned features may include, for example, recessed features, raised features, and combinations thereof.

[0020] Using spin-on processes, high wafer (substrate) throughput is achievable in semiconductor manufacturing settings, and therefore, cost of ownership is reduced compared to traditional vapor deposition due to the inherent speed of spin-on processes. Additionally, when using spin-on processes, reactions can be run through multiple cycles without moving the substrate from one bath to another and without handling the wafer, thereby reducing the potential for substrate contamination using spin-on processes. Furthermore, the use of reactants and liquids that dry completely upon application or thermal treatment without leaving water behind increases process throughput and provides a way to ensure that reactions proceed in a self-limiting manner. In some instances, spin-on processes may be performed on track-based platforms traditionally used for photoresist spin-on and thermal treatment (baking), and important applications in semiconductor manufacturing may include self-aligned multiple patterning schemes.

[0021] 2A-2F schematically illustrate, through cross-sectional views, a method of forming sidewall spacers on raised features according to embodiments of the present invention. FIG. 2A shows a patterned substrate 2 including raised features 202 and a base region 200. In some examples, the width of raised features 202 can be about 5 nm to about 200 nm, about 5 nm to about 50 nm, about 5 nm to about 20 nm, about 10 nm to about 100 nm, or about 10 nm to about 50 nm. In some examples, the height of raised features 202 can be about 10 nm to about 500 nm, about 20 nm to about 200 nm, about 20 nm to about 100 nm, about 50 nm to about 500 nm, or about 50 nm to about 200 nm.

[0022] FIG. 2B shows the patterned substrate 2 after spinning on a first reactant containing aluminum in a first liquid. Upon contact with the patterned substrate 2, a self-limiting layer 204 of the first reactant or a reaction product of the first reactant forms on the substrate 2, and excess first reactant in the first liquid is shaken off the substrate. The patterned substrate 2 is then optionally rinsed with a rinse liquid. The substrate may be spun during the rinse, which can help remove excess first reactant and reaction by-products from the patterned substrate 2. The self-limiting nature of the adsorption of the first reactant results in very high conformality, sometimes nearly perfect, over relatively high aspect ratio structures, even at very small nanometer-scale dimensions. This enables excellent thickness control and extremely low non-uniformity over large substrate areas.

[0023] 2C shows the patterned substrate 2 after spinning on a second reactant containing a silanol reagent in a second liquid. Upon contacting the substrate, a conformal layer 206 of the second reactant, or a reaction product of the second reactant, forms on the patterned substrate 2, dissolving excess silanol reagent in the second liquid. 2 reactants are shaken off the patterned substrate 2.

[0024] 2D shows the patterned substrate 2 after a thermal treatment to form a silicon oxide film from the adsorbed silanol reagents and their reaction products. The thermal treatment may be performed by raising the substrate temperature above the temperature of the spin-on and rinse steps, and may be performed at a substrate temperature high enough to drive off any remaining liquid from the substrate and fully react with the adsorbed silanol reagents to form a silicon oxide film. In some examples, the thermal treatment may include baking the substrate at a temperature between about 80°C and about 200°C, or between about 100°C and about 150°C.

[0025] FIG. 2E shows the patterned substrate 2 after repeated spin, rinse, and heat treatment steps to form a thick silicon oxide film 210.

[0026] FIG. 2F shows the patterned substrate 2 after an anisotropic dry etching process that forms sidewall spacers 212 on the sidewalls of the raised features 202.

[0027] FIG. 3 schematically illustrates a processing system 300 for processing a substrate according to an embodiment of the present invention. The processing system 300 may be a semi-enclosed spin-on deposition system, similar to those currently employed in the semiconductor industry to coat substrates (wafers) with photoresist layers. The semi-enclosed configuration enables fume control and minimizes exhaust emissions. The processing system 300 includes a process chamber 310 including a substrate holder 312 for supporting, heating, and rotating (spinning) the substrate 302, a rotation means 318 (e.g., a motor), and a liquid delivery nozzle 314 configured to provide a processing liquid 316 to the upper surface of the substrate 302. Liquid supply systems 304, 306, and 308 supply different processing liquids to the liquid delivery nozzle 314. The different processing liquids may include, for example, a first reactant containing aluminum in a first liquid, a second reactant containing a silanol reagent in a second liquid, and a rinse liquid. According to other embodiments, the processing system 300 may include additional liquid dispensing nozzles (not shown) for providing different liquids to the substrate. An exemplary rotation speed may be between about 500 rpm and about 1500 rpm, such as 1000 rpm, during exposure of the top surface of the substrate 302 to the processing liquid 316.

[0028] The processing system 300 further includes a controller 320 coupled to and capable of controlling the process chamber 310, liquid supply systems 304, 306, and 308, a liquid delivery nozzle 314, a rotation means 318, and a means for heating the substrate holder 312. The substrate 302 may be under an inert atmosphere during film deposition. The processing system 300 may be configured to process 200 mm substrates, 300 mm substrates, or larger sized substrates. As will be appreciated by those skilled in the art, the processing system 300 may be configured to process substrates, wafers, or LCDs regardless of their size. Accordingly, although aspects of the present invention are described in connection with processing semiconductor substrates, the invention is not limited thereto.

[0029] The processing system 300 may be configured to thermally treat the substrate 302 by heating the substrate holder 312. Alternatively, the substrate 302 may be transferred to a second processing system (not shown) for thermal treatment.

[0030] Processing systems and methods for liquid-phase conformal silicon oxide spin-on deposition are disclosed in various embodiments. The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. This specification and the following claims include terms that are used for descriptive purposes only and should not be construed as limiting. Those skilled in the relevant art will recognize that many modifications and variations are possible in light of the above teachings. Those skilled in the art will recognize various equivalent combinations and substitutions for the various components shown in the figures. Therefore, it is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.

Claims

1. 1. A method of processing a substrate, comprising: Providing a substrate in a process chamber; spinning a first reactant containing aluminum in a first liquid onto the substrate to form a self-limiting layer of the first reactant on the substrate; spinning a second reactant containing a silanol reagent in a second liquid onto the substrate, wherein the self-limiting layer of the first reactant catalyzes adsorption of the silanol reagent on the substrate; heat-treating the substrate to form a silicon oxide film from the adsorbed silanol reagent; A method comprising:

2. 10. The method of claim 1, further comprising sequentially repeating the spinning step at least once to increase surface saturation of the first reactant and the second reactant.

3. 10. The method of claim 1, further comprising sequentially repeating the spinning step and the thermal treatment at least once to increase the thickness of the silicon oxide film on the substrate.

4. The method of claim 1 , further comprising rinsing the substrate with a rinsing solution after one or more of the spinning steps, after the thermal treatment, or both.

5. The method of claim 4 , wherein the rinse solution comprises octane, isooctane, pyridine, toluene, a glycol, a ketone, an ether, an alcohol, or xylene.

6. 10. The method of claim 1, wherein the substrate comprises a first exposed material surface and a second exposed material surface that are different, and the silicon oxide film is selectively formed on the first exposed material surface but not on the second exposed material surface.

7. The method of claim 6 , wherein the first exposed material surface comprises a dielectric material surface and the second exposed material surface comprises a metal surface.

8. The method of claim 1 , wherein the substrate includes raised features and the silicon oxide film is conformally formed on surfaces of the raised features.

9. 10. The method of claim 1, wherein the aluminum-containing first reactant comprises an aluminum salt, an aluminum alkoxide, an organometallic aluminum compound, or an organometallic aluminum compound.

10. The method of claim 1 , wherein the second reactant containing a silanol reagent comprises an alkoxysilanol.

11. 11. The method of claim 10, wherein the alkoxysilanol comprises tris(tert-butoxy)silanol, tris(tert-pentoxy)silanol, methyl-bis(tert-butoxy)silanol, or methyl-bis(tert-pentoxy)silanol.

12. The method of claim 1, wherein the heat treatment comprises baking the substrate at a temperature between about 80°C and about 200°C.

13. The method of claim 1, wherein the heat treatment comprises baking the substrate at a temperature between about 100°C and about 150°C.

14. 10. The method of claim 1, wherein one or more of the spinning of the first reactant on the substrate, the spinning of the second reactant on the substrate, and the thermal treatment are performed under an inert atmosphere that is substantially free of moisture.

15. 1. A method of processing a substrate, comprising: providing a substrate in a process chamber, the substrate including raised features; spinning a first reactant comprising trimethylaluminum in a first liquid onto the substrate to form a self-limiting layer of the first reactant on the substrate; spinning a second reactant containing a silanol reagent in a second liquid onto the substrate, wherein the self-limiting layer of trimethylaluminum catalyzes adsorption of the silanol reagent on the substrate; heat-treating the substrate to form a conformal silicon oxide film on the surface of the raised features from the adsorbed silanol reagent; A method comprising:

16. The method of claim 15, wherein the silanol reagent comprises tris(tert-butoxy)silanol, tris(tert-pentoxy)silanol, methyl-bis(tert-butoxy)silanol, or methyl-bis(tert-pentoxy)silanol.

17. The method of claim 15, wherein the heat treatment comprises baking the substrate at a temperature between about 80°C and about 200°C.

18. 16. The method of claim 15, further comprising sequentially repeating the spinning of the first reactant on the substrate, the spinning of the second reactant on the substrate, and the thermal treating at least once to increase the thickness of the silicon oxide film on the substrate.

19. 1. A method of processing a substrate, comprising: providing a substrate in a process chamber, the substrate including a first exposed material surface and a second exposed material surface that are different; spinning a first reactant comprising trimethylaluminum in a first liquid onto the substrate to selectively form a self-limiting layer of the trimethylaluminum on the first exposed material surface on the substrate; spinning a second reactant containing a silanol reagent in a second liquid onto the substrate, wherein the self-limiting layer of trimethylaluminum catalyzes selective adsorption of the silanol reagent on the first exposed material surface; thermally treating the substrate to selectively form a conformal silicon oxide film on the first exposed material surface from the adsorbed silanol reagent; A method comprising:

20. The method of claim 19, wherein the silanol reagent comprises tris(tert-butoxy)silanol, tris(tert-pentoxy)silanol, methyl-bis(tert-butoxy)silanol, or methyl-bis(tert-pentoxy)silanol.

21. 20. The method of claim 19, further comprising sequentially repeating the spinning of the first reactant on the substrate, the spinning of the second reactant on the substrate, and the thermal treating at least once to increase a thickness of the silicon oxide film on the first exposed material surface.

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