High-throughput deposition method

Abstract

This invention provides a plasma-excited atomic layer deposition (PEALD) method for depositing etching-resistant SiOCN films. [Solution] The PEALD method, which provides films with improved growth rate, improved step coverage, and excellent etching resistance to deposition plasma post-treatment containing wet etchants and O2 co-reactants, relies on a single precursor—bis(dialkylamino)tetraalkyldisiloxane—along with a hydrogen plasma to deposit etching-resistant thin films of SiOCN. Since the films can be deposited using a single precursor, the entire method exhibits improved throughput.

Description

[Technical Field]

[0001] Overall, the present invention relates to materials and methods for depositing thin films of silicon oxycarbonite (SiOCN) on the surface of microelectronic devices. These films act as low dielectric constant insulators with excellent wet etching resistance, dry etching resistance, and ashing resistance. [Background technology]

[0002] Silicon nitride (SiN) has been used as a source and drain spacer (S / D spacer) for field-effect transistors (FinFETs) and all-around gate (GAA) structures due to its high wet etching and oxygen (O2) ashing resistance. However, SiN has a high dielectric constant (k) of approximately 7.5. Carbon and nitrogen-doped silicon dioxide (SiO2) SiOCN spacers have been developed to lower the dielectric constant while maintaining excellent etching and ashing resistance. Currently, the k value of the best etching and ashing resistant SiOCN dielectrics is approximately 4.0. Etching and ashing resistant dielectrics with a k value of <3.5 are required for next-generation devices.

[0003] In addition, there remains a demand for improved organosilicon precursors for forming silicon-containing films in the manufacturing of microelectronic devices, particularly in methods utilizing low-temperature deposition techniques used for forming SiOCN films. Specifically, there is a demand for liquid silicon precursors with good thermal stability, high volatility, and reactivity with substrate surfaces.

[0004] Improving device performance requires new materials to enhance the ability to isolate both transistors and interconnect circuits. These films often require low dielectric constants (i.e., <4) while also being resistant to subsequent fabrication processes during device manufacturing, including wet and dry etching resistance. Furthermore, the deposited insulator must not change when exposed to post-deposition treatment. When these films are deposited front-end-of-line, they must isometrically cover the 3D structure while exhibiting uniform dielectric properties throughout the entire structure, as seen in FinFET devices. Since the film remains within the device, its electrical properties cannot be altered by post-deposition treatment. Plasma-based deposition methods often result in films with non-uniform electrical properties, as the top layer of the film is modified by enhanced plasma shock. Simultaneously, the sidewalls of a 3D structure covered with the same film may exhibit diverse properties as a result of reduced electron shock during deposition. Nevertheless, the film must withstand wet etching and / or plasma post-treatment in an oxidizing or reducing atmosphere. [Overview of the project]

[0005] This invention provides a plasma-excited atomic layer deposition (PEALD) method for depositing etching-resistant SiOCN films. These films offer improved growth rates, improved step coverage, and improved etching resistance to deposition plasma post-treatments containing wet etchants and O2 co-reactants. This PEALD method relies on a single precursor, such as bis(dialkylamino)tetraalkyldisiloxane, along with a hydrogen plasma, for depositing etching-resistant SiOCN thin films. Since the films can be deposited using a single precursor, the entire method exhibits improved throughput. The films show resistance to wet etching with dilute hydrofluoric acid (HF) aqueous solution both after deposition and after deposition plasma post-treatment. Therefore, these films are expected to exhibit excellent stability to post-deposition fabrication processes used during device manufacturing and assembly (see Figures 2 and 3).

[0006] In a first embodiment, the present invention relates to a method for depositing an SiOCN film onto the surface of a microelectronic device, comprising reactants selected from the following: a. At least one of the following formulas TIFF2026122959000001.tif38170b.[In the formula, each R 1 R is independently selected from hydrogen and C1-C4 alkyl groups, and each R 2 The elements are independently selected from hydrogen and C1-C4 alkyl groups; and each R 3 R is selected from hydrogen and C1-C4 alkyl, however R 3 If R is hydrogen, 1 Compounds of C1-C4 alkyl groups; and reducing or oxidizing gases in plasma form purged with each reactant before exposing the film to the next reactant. The present invention provides a method that includes introducing into the reaction zone.

[0007] This disclosure can be better understood by considering the following description of various exemplary embodiments in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the SiOCN thickness in angstroms as a function of PEALD cycle number. This data was generated using bis(diethylamino)tetramethyldisiloxane under atomic layer deposition (ALD) conditions of 265°C, with a 2-second pulse of silicon precursor followed by a 5-second pulse of hydrogen plasma at 250 watts. The method resulted in film formation of approximately 0.2 Å per cycle. [Figure 2] This figure shows the thickness of the oxide film as a function of etching time, illustrating the wet etching resistance (WER) of less than 0.1 Å per minute using 50:1 diluted hydrofluoric acid (DHF). The SiOCN film of the present invention is compared to thermal oxidation. [Figure 3]A diagram showing the difference in etching depth obtained by comparing the etching depth of the SiOCN film of the present invention immediately after deposition with the etching depth after exposure to an ashing plasma output ranging from 100 to 400 watts. This data illustrates an ashing depth of approximately 7 Å per minute at 100 watts. This data illustrates equivalent ashing resistance compared to SiN. [Figure 4] A diagram showing XPS of the atomic percentages of the constituent atoms of the SiOCN film of Example 1 at various depths of the film. In the bulk of the film, the composition is as follows: 16.6 atomic percentage of carbon, 19.3 atomic percentage of nitrogen, 24.7 atomic percentage of oxygen, and 39.4 atomic percentage of silicon.

BRIEF DESCRIPTION OF THE INVENTION

[0009] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0010] The term "about" generally refers to a range of numbers that are considered equivalent to the recited value (e.g., those having the same function or result). In many instances, the term "about" may also include numbers that are rounded to the nearest significant digit.

[0011] Numerical ranges expressed using endpoints include all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0012] In a first aspect, the present invention is a method for depositing a SiOCN film on a microelectronic device surface in a reaction zone, the reactants being selected from: a. at least one of the following formulas TIFF2026122959000002.tif38170[where each R 1 is independently selected from hydrogen and C1-C4 alkyl, and each R 2 is independently selected from hydrogen and C1-C4 alkyl; and each R 3 is selected from hydrogen and C1-C4 alkyl, provided that when R 3 is hydrogen, R 1 is C1-C4 alkyl]; and b. exposing the membrane to a reducing or oxidizing gas in a plasma form purged with each reactant prior to exposing the membrane to the following reactants and introducing the same into the reaction zone.

[0013] In the method step, a. and b. represent a pulse sequence including one cycle. This cycle may be repeated until the deposited film reaches the desired thickness.

[0014] In this method, the compound of formula (I) is such that R 1 is selected from hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl, R 2 is selected from hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl, and R 3 is selected from hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl. In this method, when R 3 is hydrogen, R 1 is C1-C4 alkyl. In one embodiment, each R 1 and each R 3 is ethyl, and each R 2 is methyl, i.e., a compound of the following formula. TIFF2026I22959000003.tif48170

[0015] As used herein, the term "SiOCN" film refers to a film containing silicon, oxygen, carbon, and nitrogen in various proportions. In one embodiment, the present invention relates to approximately (i) Silicon in an atomic percentage of 30 to 50 atoms; (ii) Nitrogen in an atomic percentage of 5 to 30 atoms; (iii) Carbon in 2 to 25 atomic percentages; and (iv) Oxygen in 20 to 40 atomic percentages To provide a membrane having [a certain characteristic].

[0016] In another embodiment, the present invention is approximately (i) Silicon in an atomic percentage of 25 to 45; (ii) Nitrogen in an atomic percentage of 10 to 25 atoms; (iii) Carbon in 5 to 20 atomic percentages; and (iv) Oxygen in 25 to 35 atomic percentages To provide a membrane having [a certain characteristic].

[0017] In certain embodiments, the SiOCN film of the present invention has about 15 to about 20 atomic percentages of nitrogen, and in other embodiments, it has about 8 to about 18 atomic percentages of carbon.

[0018] Generally, compounds of formula (I) can be prepared by treatment with the corresponding halodisiloxane having a primary or secondary amine.

[0019] The compound can be employed to form high-purity silicon-containing thin films using any suitable ALD technology and pulsed plasma method. Such deposition methods can be used to form silicon-containing films on microelectronic devices by utilizing deposition temperatures from about 200°C to about 550°C, and can form films with a thickness of about 20 angstroms to about 200 angstroms.

[0020] In the method of the present invention, the compound of formula (I) may be reacted with a desired microelectronic device substrate by any suitable method, for example, in a single wafer chamber or in a furnace containing multiple wafers.

[0021] Alternatively, the method of the present invention may be carried out in the manner of an ALD-like method. As used herein, the terms “ALD or ALD-like” refer to a method in which each reactant is continuously introduced into a reactor such as a single wafer ALD reactor, a semi-batch ALD reactor, or a batch furnace ALD reactor, or a method in which each reactant is exposed to the surface of a substrate or microelectronic device by moving or rotating the substrate to various sections of the reactor, and each section being isolated by an inert gas curtain, i.e., in a spatial ALD reactor or a roll-to-roll ALD reactor.

[0022] In one embodiment, the present invention relates to a PEALD for depositing a SiOCN film using a compound of formula (I) together with a reducing gas in plasma form. A nitrogen plasma may be useful for forming a film having a higher nitrogen atom percentage while utilizing the compound of formula (I) and a reducing gas in plasma form as taught herein. Thus, in another embodiment, the present invention relates to a method for depositing a SiOCN film on the surface of a microelectronic device in a reaction zone, wherein the reactants are selected from the following: a. At least one of the following formulas TIFF2026122959000004.tif38170[In the formula, each R 1 R is independently selected from hydrogen and C1-C4 alkyl groups, and each R 2 The elements are independently selected from hydrogen and C1-C4 alkyl groups; and each R 3 R is selected from hydrogen and C1-C4 alkyl, however R 3 If R is hydrogen, 1 Compounds that are C1-C4 alkyl; and b. Reducing gas in plasma form, purged with each reactant before exposing the film to the next reactant. The present invention provides a method that includes continuously introducing into the reaction zone.

[0023] As used herein, the term “reducing gas in plasma form” refers to a reducing gas in plasma form consisting of a gas selected from hydrogen (H2), hydrazine (N2H4); methylhydrazine, t-butylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine (C1-C4 alkylhydrazines), which is used alone as an inert gas such as N2, helium, or argon, or in combination with a plasma formed from such an inert gas. For example, a continuous flow of an inert gas such as argon is used while simultaneously introducing a radio frequency electromagnetic field (Rf), and then supplying plasma H2 by introducing hydrogen. Typically, the plasma output used ranges from approximately 50 to 500 watts at 13.6 MHz.

[0024] Similarly, oxidizing gases may be used in various cycles of film deposition to increase the oxygen content and decrease the carbon content of the film. Suitable oxidizing gases include O2, O2 plasma, ozone (O3), water (H2O), and nitrous oxide (N2O). Embodiments utilizing oxidizing gas pulses may be used sequentially, along with the use of reducing gases in other pulse sequences.

[0025] In certain embodiments, the pulse time (i.e., exposure time to the substrate) of the reactants described above (i.e., the compound of formula (I) and the reducing gas in plasma form) ranges from about 1 to 10 seconds. When a purging step is utilized, the time is about 1 to 10 seconds or 2 to 5 seconds. In other embodiments, the pulse time for each reactant ranges from about 2 to about 5 seconds.

[0026] The methods disclosed herein require one or more purge gases. The purge gas, used to clear away unconsumed reactants and / or reaction by-products, is an inert gas that does not react with the precursors. Exemplary purge gases include, but are not limited to, argon, nitrogen, helium, neon, hydrogen, and mixtures thereof. In certain embodiments, a purge gas such as Ar is supplied into the reactor at a flow rate ranging from about 10 to about 2000 sccm for about 0.1 to 1000 seconds to purge any unreacted materials and any by-products that may remain in the reactor.

[0027] Each step of supplying the compound of formula (I), the reducing gas in plasma form, and / or other precursors, source gas, and / or reagents may be carried out by changing the sequence in which they are supplied and / or changing the stoichiometric composition of the resulting dielectric film.

[0028] In the method of the present invention, energy is supplied to various reactants to induce a reaction and to form a SiOCN film on a microelectronic device substrate. The energy may be supplied by, but is not limited to, heat, pulsed heat, plasma, pulsed plasma, high-density plasma, inductively coupled plasma, remote plasma methods, and combinations thereof. In certain embodiments, a second RF frequency source may be used to modify the plasma properties on the substrate surface. In embodiments where deposition requires plasma, the plasma generation method may include a direct plasma generation method in which the plasma is generated directly within the reactor, or alternatively, a remote plasma generation method in which the plasma is generated "remotely" in the reaction zone and the substrate is supplied into the reactor.

[0029] As used herein, the term “microelectronic device” refers to a semiconductor substrate including a single non-volatile flash memory in which memory cells are vertically stacked in multiple layers (3D NAND), a flat panel display, and microelectromechanical systems (MEMS) manufactured for use in microelectronic, integrated circuit, or computer chip applications. The term “microelectronic device” should be understood to include any substrate that may ultimately become a microelectronic device or microelectronic component, including n-type metal oxide semiconductor (nMOS) and / or p-type metal oxide semiconductor (pMOS) transistors, but is not intended to be limited in any way. Such microelectronic devices contain, for example, at least one substrate which can be selected from silicon, SiO2, Si3N4, OSG, FSG, silicon carbide, hydride silicon carbide, silicon nitride, hydride silicon nitride, silicon carbonitride, hydride silicon carbonitride, boron nitride, anti-reflective coatings, photoresists, germanium, germanium-containing materials, boron-containing materials, Ga / As, flexible substrates, porous inorganic materials, metals such as copper and aluminum, and, but not limited to, diffusion barrier layers such as TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, or WN. The film is compatible with various subsequent processing steps, such as chemical mechanical polishing (CMP) and anisotropic etching methods.

[0030] These films offer low etching resistance to wet etchants and O2 plasma. The O2 plasma ashing method was performed at 340°C and a pressure of 3 Torr with a 500 sccm O2 flow and plasma powers of 100, 250, and 400 W for 1 minute. In this regard, referring to Figure 3, the present invention, in another embodiment, provides an SiOCN film that exhibits an ashing damage difference of only about 2.5 angstroms compared to a silicon nitride reference sample when exposed to a 250 watt oxygen plasma for 60 seconds.

[0031] As described above, in certain embodiments, the SiOCN film of the present invention has about 15 to about 25 atomic percentages of nitrogen and about 16 atomic percentages of carbon. By utilizing the method of the present invention, such a SiOCN film having a dielectric constant (k) of less than about 5 can be prepared.

[0032] Generally, the desired thickness of a SiOCN film prepared in this way is approximately 20 Å to 200 Å.

[0033] Doping a low k SiCO film with nitrogen via the interaction between precursors of formula (I), followed by a reaction using an H2 plasma, dramatically improves the wet etching resistance and O2 plasma ashing resistance of the resulting SiOCN film.

[0034] In the method of the present invention, the flow rate of the precursor of formula (I) may be about 10 to 50 mg per PEALD cycle.

[0035] In another embodiment, the present invention relates to the following formula TIFF2026122959000005.tif38170[In the formula, each R 1 R is independently selected from hydrogen and C1-C4 alkyl groups, and each R 2 The elements are independently selected from hydrogen and C1-C4 alkyl groups; and each R 3 R is selected from hydrogen and C1-C4 alkyl, however R 3 If R is hydrogen, 1 The present invention provides compounds that are C1-C4 alkyl.

[0036] Such compounds are useful as precursors in the deposition of silicon-containing films. In one embodiment, each R 1 is ethyl, and each R 2 is methyl, and each R 3 is ethyl. In another embodiment, each R 1 isopropyl, and each R 3 is hydrogen, and each R 2 It is methyl.

[0037] The present invention can be further illustrated by the following examples of specific embodiments of the invention, but these examples are included for illustrative purposes only and are not intended to limit the scope of the invention unless otherwise indicated. [Examples]

[0038] Example 1 Sedimentation using bis(diethylamino)tetramethyldisiloxane as a single precursor

[0039] SiCON deposition in PEALD was performed using the PEALD system with a susceptor temperature of 300°C, a showerhead temperature of 170°C, a chamber pressure of 3 Torr, and an ambient inert gas flow of 500 sccm. The coupon temperature during deposition was approximately 265°C.

[0040] The H2 plasma was generated using a direct plasma system that generated plasma between a showerhead and a susceptor / wafer. The plasma output was fixed at 250W, and the plasma pulse duration was fixed at 5 seconds.

[0041] The pulse scheme for SiOCN's PEALD consisted of the following: 1. A 2-second pulse of the [bis(diethylamino)tetramethyldisiloxane] precursor. 2. Inert gas purging for 5 seconds 3. 5-second H2 plasma pulse 4. 5-second inert gas purge

[0042] Example 2 Synthesis of 1,3-bis(diethylamide)tetramethyldisiloxane

[0043] 400 mL of diethylamine (3.87 mol, 4.4 equivalents) and 3 L of anhydrous diethyl ether were added to a 5 L round-bottom flask with four necks, equipped with a mechanical stirrer, thermocouple, gas / vacuum inlet adapter, and condenser with a tube inlet. 173 mL (0.885 mol, 1.0 equivalent) of 1,3-dichlorotetramethyldisiloxane in 600 mL of anhydrous hexane was packed into a 1 L flask with a gas / vacuum inlet valve. Both flasks were cooled to approximately -5°C in a brine bath and then connected with PTFE tubing. The 1,3-dichlorotetramethyldisiloxane solution was added in portions to the stirred amine solution, maintaining the internal temperature below 0°C. Once the additions were complete, the reaction mixture was gradually warmed to room temperature and stirred for 48 hours. The reaction mixture, which contained a large amount of diethylamine hydrochloride, was filtered into a 5 L flask under an inert atmosphere, and the salt was washed with 2 × 1.5 L aliquots of anhydrous diethyl ether. The solvent was removed from the filtrate under vacuum, and the resulting clear yellow oily substance (230.7 g) was distilled in a short-path distillation head at a pressure of 100 mtorr to obtain 156.5 g of product (yield 64%, purity >98%). 1 ¹H NMR (d6-benzene): d 2.85 (q, 2H), 1.09 (t, 3H), 0.19 (s, 2H). 13 ¹³C NMR (d6-benzene): d 40.5, 16.7, 0.7. 29 Si NMR (d6-benzene) -13.4

[0044] Example 3 Synthesis of 1,3-bis(isopropylamide)tetramethyldisiloxane

[0045] Isopropylamine (4.4 equivalents) and 3 L of anhydrous diethyl ether were added to a 5 L round-bottom flask with four necks, equipped with a mechanical stirrer, thermocouple, gas / vacuum inlet adapter, and condenser with a tube inlet. 173 mL (0.885 mol, 1.0 equivalent) of 1,3-dichlorotetramethyldisiloxane in 600 mL of anhydrous hexane was packed into a 1 L flask with a gas / vacuum inlet valve. Both flasks were cooled to approximately -5°C in a brine bath and then connected with PTFE tubing. The 1,3-dichlorotetramethyldisiloxane solution was added in portions to the stirred amine solution, maintaining the internal temperature below 0°C. Once the additions were complete, the reaction mixture was gradually warmed to room temperature and stirred for 48 hours. The reaction mixture, which contained a large amount of isopropylamine hydrochloride, was filtered into a 5 L flask under an inert atmosphere, and the salt was washed with 2 × 1.5 L aliquots of anhydrous diethyl ether. The solvent was removed from the filtrate under vacuum, resulting in a clear, yellowish oily substance. This oily substance was then purified by subsequent vacuum distillation.

[0046] Having described several exemplary embodiments of this disclosure, those skilled in the art will readily understand that further embodiments can be created and used within the scope of the claims appended herein. Many of the advantages of this disclosure as encompassed herein are stated in the foregoing description. However, it will be understood that this disclosure is, in many respects, merely illustrative. Naturally, the scope of this disclosure is defined in the language in which the appended claims are expressed.

Claims

1. A method for depositing a silicon oxycarbonite film onto the surface of a microelectronic device, a. At least one of the following formulas [Wherein each R １ is independently selected from hydrogen and C １ -C ４ alkyl; each R ２ is independently selected from hydrogen and C １ -C ４ alkyl; and each R ３ is selected from hydrogen and C １ -C ４ alkyl, provided that when R ３ is hydrogen, R １ is C １ -C ４ alkyl]; and b. A plasma-form reducing gas or oxidizing gas, accompanied by purging of each reactant before exposing the film to the next reactant. A method comprising introducing a reactant selected from into a reaction zone.

2. Each R １ The method according to claim 1, wherein is ethyl.

3. Each R ２ The method according to claim 1, wherein is methyl.

4. The method according to claim 1, wherein the reducing gas is selected from hydrogen, hydrazine; methylhydrazine, t-butylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine.

5. The method according to claim 4, wherein the reducing gas is hydrogen.

6. The method according to claim 1, wherein the oxidizing gas is selected from oxygen, oxygen plasma, ozone, water, and nitrous oxide.

7. The method according to claim 1, further comprising repeating a. and b. until a film of a desired thickness is obtained.

8. A method for depositing a silicon oxycarbonite film onto the surface of a microelectronic device, a. At least one of the following formulas [In the formula, each R １ is hydrogen and C １ -C ４ Selected independently from alkyl, each R ２ is hydrogen and C １ -C ４ Selected independently of alkyl groups; and each R ３ is hydrogen and C １ -C ４ Selected from alkyl, however R ３ If R is hydrogen, １ is C １ -C ４ Compounds that are alkyl; and b. Reducing gas in plasma form, purged from each reactant before exposing the film to the next reactant. A method comprising introducing a reactant selected from into a reaction zone.

9. Each R １ The method according to claim 8, wherein is ethyl.

10. Each R ２ The method according to claim 8, wherein is methyl.

11. The method according to claim 7, wherein the reducing gas is selected from hydrogen, hydrazine; methylhydrazine, t-butylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine.

12. The method according to claim 11, wherein the reducing gas is hydrogen.

13. The method according to claim 11, further comprising repeating a. and b. until a film of a desired thickness is obtained.

14. The method according to claim 13, wherein the formed silicon phosphate carbonitride film exhibits a low ashing damage difference of approximately 2.5 angstroms compared to a silicon nitride reference sample when exposed to an oxygen plasma at 250 watts for 60 seconds.

15. The following formula [In the formula, each R １ is hydrogen and C １ -C ４ Selected independently from alkyl, each R ２ is hydrogen and C １ -C ４ Selected independently of alkyl groups; and each R ３ is hydrogen and C １ -C ４ Selected from alkyl, however R ３ If R is hydrogen, １ is C １ -C ４ A compound that is alkyl.

16. Each R １ is ethyl, and each R ２ is methyl, and each R ３ The compound according to claim 15, wherein is ethyl.

17. Each R １ isopropyl, and each R ３ is hydrogen, and each R ２ The compound according to claim 15, wherein is methyl.

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