Silicon Precursor Compounds and Methods for Forming Silicon-Containing Films

Abstract

Certain silicon precursor compounds useful in the formation of silicon-containing films in the manufacture of semiconductor devices are provided, and more particularly, compositions and methods for forming such silicon-containing films, such as films comprising silicon dioxide, are provided.

Description

Technical Field

[0001] Generally, the present invention relates to a method and a precursor for depositing a silicon-containing film on the surface of a microelectronic device.

Background Art

[0002] In semiconductor manufacturing, thin (e.g., less than 1000 nanometers thick) passivation layers of chemically inert dielectric materials such as silicon nitride (Si 3 N 4 ), silicon oxynitride (SiO x N y ), silicon carbide (SiC), silicon carbonitride (SiCN) and silicon oxycarbide (SiCO) and / or silicon dioxide (SiO 2 ) are widely used in microelectronic device structures and function as structural elements of multilayer devices such as sidewall spacer elements, diffusion masks, oxidation barriers, trench isolation coatings, intermetal dielectric materials, passivation layers, insulators and etch stop layers.

[0003] The deposition of silicon-containing films by chemical vapor deposition techniques is a very attractive method for forming such films. For example, a chemical vapor deposition (CVD) process at a low deposition temperature of less than about 450°C is particularly desirable, but for such purposes, it is necessary that suitable silicon precursor compounds be available. Optionally, higher deposition temperatures may be considered when the thermal budget of the integrated circuit permits. In these cases, temperatures above 450°C can be utilized to achieve the desired dielectric film. Therefore, there is a need for precursors for forming silicon-containing films that can be utilized at such high temperatures. In particular, liquid silicon precursors having good thermal stability, high volatility and reactivity with the substrate surface are needed.

Summary of the Invention

[0004] The present invention generally relates to the formation of silicon-containing films in the manufacture of semiconductor devices, and more specifically, to compositions and methods for forming such silicon-containing films. In one particular embodiment, it has been found that the precursor tris(dimethylsilyl)methane is useful for forming high-purity silicon dioxide films with a high growth rate, namely about 1.7 Å / cycle at 600 °C, using ozone as the oxidizing gas (see Figure 1). Further, as shown in the data presented in Figure 3, the wet etching rate (WER) of the film obtained from this precursor was improved by about 77% compared to a silicon dioxide film formed using BTBAS with ozone. Additionally, when compared to thermal oxides, the wet etching rate (200:1 diluted hydrofluoric acid (HF)) of the silicon dioxide film formed using the precursor compound of the present invention in combination with ozone is less than about three times the wet etching rate of thermally grown silicon dioxide. Tris(dimethylsilyl)methane (TDMSM) has been found to be thermally stable at temperatures above 600 °C and is thus useful in atomic layer deposition processes at relatively high temperatures where high-purity silicon dioxide films are desired.

Brief Description of the Drawings

[0005]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0006] 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 the sense of "and / or" unless the context clearly dictates otherwise.

[0007] The term "about" generally refers to a range of numbers that are considered equivalent to the recited value (e.g., having the same function or result). In many cases, the term "about" can include numbers that are rounded to the nearest significant digit.

[0008] 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).

[0009] In a first aspect, the present invention is a method for forming a silicon-containing film on the surface of a microelectronic device in a reaction region, comprising at least one compound of formula (I): TIFF0007683037000001.tif43170(wherein each R 1 and each R 2 is independently selected from hydrogen and C 1 to C 10 alkyl) including introducing it into the reaction region under vapor deposition conditions. C 1 ~C 10 Examples of alkyl include methyl, ethyl, n-propyl, n-butyl and the like.

[0010] In one embodiment, each R 1 is hydrogen, and each R 2 is methyl. In this embodiment, the compound of formula (I) has the following structure: TIFF0007683037000002.tif42170 and is referred to herein by the abbreviation "TDMSM".

[0011] In other embodiments, each R 2 is ethyl, each R 2 is n-propyl, each R 2 is n-butyl, or each R 2 is independently selected from methyl, ethyl, n-propyl or n-butyl.

[0012] The compound of formula (I) is useful as a precursor in the vapor deposition of silicon-containing films, particularly films on the surface of microelectronic devices. In certain embodiments, the film also contains nitrogen and / or oxygen and / or carbon.

[0013] Here, the "silicon-containing film" refers to films such as silicon dioxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, silicon oxycarbonitride, low dielectric constant (Low-k) silicon-containing thin films, high dielectric constant (High-k) gate silicate films and low temperature silicon epitaxial films.

[0014] In certain embodiments, the vapor deposition conditions include reaction conditions known as chemical vapor deposition, pulsed chemical vapor deposition and atomic layer deposition. In the case of pulsed chemical vapor deposition, regardless of the presence or absence of an intermediate (inert gas) purge step, a series of alternating pulses of the precursor compound and the co-reactant can be utilized to build the film thickness to the desired end point.

[0015] In certain embodiments, the pulse time of the above precursor compound (i.e., the duration of precursor exposure to the substrate) ranges from about 1 to 30 seconds. When a purge step is performed, the duration is about 1 to 20 seconds or 1 to 30 seconds. In other embodiments, the pulse time of the co-reactant ranges from 5 to 60 seconds.

[0016] In one embodiment, the deposition conditions include a temperature of about 100°C to about 1000°C, such as about 450°C to about 1000°C, and a pressure of about 0.5 to about 1000 Torr. In another embodiment, the deposition conditions include a temperature of about 100°C to about 800°C, such as about 500°C to about 750°C.

[0017] The above compounds can be used to form high-purity silicon-containing thin films by any suitable deposition technique such as chemical vapor deposition (CVD), digital (pulse) CVD, atomic layer deposition (ALD), pulsed plasma method, plasma enhanced cyclical chemical vapor deposition (PECCVD), fluidized chemical vapor deposition (FCVD) or plasma ALD-like processes. By such a deposition process, a silicon-containing film can be formed on a microelectronic device, and a film with a thickness of about 20 angstroms to about 2000 angstroms can be formed.

[0018] In the process of the present invention, the above compounds may be reacted with a desired microelectronic device substrate in any suitable manner, for example, in a single-wafer CVD, ALD and / or PECVD or PEALD chamber, or in a furnace containing multiple wafers.

[0019] Alternatively, the process of the present invention can be carried out as an ALD or ALD-like process. As used herein, the term "ALD or ALD-like" means that (i) each reactant containing the silicon precursor compound of formula (I) and an oxidation and / or reduction gas is sequentially introduced into a reactor such as a single-wafer ALD reactor, a semi-batch ALD reactor, or a batch furnace ALD reactor, or (ii) each reactant containing the silicon precursor compound of formula (I) and an oxidation and / or reduction gas is exposed to a substrate or the surface of a microelectronic device by moving or rotating the substrate in different compartments of the reactor, and each compartment is separated by an inert gas curtain, i.e., a spatial ALD reactor or a roll-to-roll ALD reactor.

[0020] Generally, the desired film produced using the precursor compound of formula (I) can be adjusted by selecting each compound and combining it with the use of a reducing or oxidizing co-reactant. For example, refer to Scheme 1 below which shows how the precursor of formula (I) can be used in a deposition process. TIFF0007683037000003.tif41170 Scheme 1

[0021] In one embodiment, the deposition process further includes a step of exposing the precursor to a gas such as H 2 、H 2 plasma, H 2 / O 2 mixture, water, N 2 O, N 2 O plasma, NH 3 、NH 3 plasma, N 2 、or N 2 plasma. For example, an oxidizing gas such as O 2 、O 3 、N 2 O, water vapor, alcohol, oxygen plasma, etc. can be used. In one embodiment, in the ALD process, the precursor TDMSM is O 3It is used together. In certain embodiments, the oxidizing gas further comprises an inert gas such as argon, helium, nitrogen, or combinations thereof. In another embodiment, the oxidizing gas further comprises nitrogen, which can react with the precursor of formula (I) under plasma conditions to form a silicon oxynitride film.

[0022] In one embodiment, the present invention relates to a high-temperature thermal atomic layer deposition (ALD) process for depositing a silicon dioxide film with a low wet etching rate using ozone as the oxidizing gas.

[0023] In another embodiment, the deposition process may further include a step of exposing the film to a reducing gas. In certain embodiments of the present invention, the reducing gas is H 2 , hydrazine (N 2 H 4 ), methylhydrazine, t-butylhydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, and NH 3 and is composed of a gas selected from.

[0024] The compound of formula (I) enables low-temperature PECVD and / or PEALD formation of silicon-containing films as well as high-temperature ALD. Such compounds exhibit high volatility and chemical reactivity, but are stable against thermal decomposition at the temperatures involved in the volatilization or vaporization of the precursor, so that the resulting precursor vapor can be consistently and repeatedly fed into the deposition region or reaction chamber. In this regard, surprisingly, it has been found that TDMSM is stable at temperatures above 600 °C, and furthermore, TDMSM does not show thermal degradation up to about 650 °C. Due to the chemical reactivity of the compound of formula (I), film formation using low-temperature PEALD technology is possible, in which conventional silicon precursor materials such as TEOS are inert and thus show little or no deposition behavior. Furthermore, as described above, FIG. 3 graphically shows the significantly improved wet etching performance of an exemplary compound of formula (I) of the present invention (i.e., TDMSM), which exceeds the performance of the known silicon precursor BTBAS (bis(tert-butylamino)silane).

[0025] Thus, in a further embodiment, the present invention provides that the silicon-containing film is silicon dioxide, and the wet etching rate exhibited by the silicon dioxide film formed in such a manner is at least about 70% improved compared to the wet etching rate of SiO 2 deposited using BTBAS and ozone. As described above, when compared with thermal oxide, the wet etching rate (200:1 diluted HF) exhibited by the silicon oxide film formed by using the precursor compound of the present invention in combination with ozone is less than about three times the wet etching rate of thermally grown silicon oxide. Thus, in a further aspect, the present invention provides a silicon oxide film having a wet etching rate with a 200:1 diluted hydrogen fluoride solution of less than about three times the etching rate of thermally grown silicon oxide.

[0026] When using the precursor compound of formula (I), carbon and nitrogen may be incorporated into such a film by introducing an additional amount of carbon, such as carbon in the form of methane, ethane, ethylene or acetylene, as a co-reactant to form silicon carbide. Similarly, nitrogen may be introduced using a nitrogen-containing reducing gas.

[0027] The deposition method disclosed herein may include one or more purge gases. The purge gas used to purge unconsumed reactants and / or reaction by-products is an inert gas that does not react with the precursor. 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 to the reactor for about 0.1 to 1000 seconds in the range of a flow rate of about 10 to about 2000 sccm to purge any unreacted materials and any by-products that may remain in the reactor.

[0028] Each step of supplying the silicon precursor compound, the oxidizing gas, the reducing gas and / or other precursors, source gases and / or reagents can be carried out by changing the order in which they are supplied and / or by changing the stoichiometric composition of the resulting dielectric film.

[0029] Energy is applied to at least one of the silicon precursor compound of formula (I) and an oxidation gas, a reduction gas, or a combination thereof to induce a reaction, and a silicon-containing film is formed on a microelectronic device substrate. Such energy can be provided by, but is not limited to, heat, pulse heat, plasma, pulse plasma, helicon plasma, high density plasma, inductively coupled plasma, X-rays, electron beam, photons, remote plasma method, and combinations thereof. In certain embodiments, a secondary RF frequency source can be used to vary the plasma characteristics of the substrate surface. In embodiments where plasma is involved in the deposition, the plasma generation process can include a direct plasma generation process in which plasma is generated directly in the reactor, or alternatively, a remote plasma generation process in which plasma is generated "remotely" from the reaction region and the substrate and supplied into the reactor.

[0030] As used herein, the term "microelectronic device" corresponds to a semiconductor substrate including a 3D NAND structure, a flat panel display, and a microelectromechanical system (MEMS) manufactured for use in microelectronics, integrated circuits, or computer chip applications. The term "microelectronic device" is not meant to be limiting in any way and includes negative channel metal oxide semiconductor (nMOS) and / or positive channel metal oxide semiconductor (pMOS) transistors and any substrate that will ultimately become a microelectronic device or microelectronic assembly. Such microelectronic devices are, for example, silicon, SiO 2 、Si 3 N 4, including at least one substrate selectable from OSG, FSG, silicon carbide, silicon hydride, silicon nitride, silicon nitride hydride, silicon carbonitride, silicon carbonitride hydride, boron nitride, an antireflection coating, a photoresist, germanium, germanium-containing, boron-containing, gallium arsenide (Ga / As), a flexible substrate, a porous inorganic material, metals such as copper and aluminum, and diffusion barrier layers such as, but not limited to, TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, or WN. The film is compatible with various subsequent process steps such as, for example, chemical mechanical planarization (CMP) and anisotropic etching processes.

[0031] The compound of formula (I) can be prepared by reacting tribromomethane with chlorodimethylsilane in the presence of magnesium. As an example, Scheme 2 below shows each R 1 is hydrogen and each R 2 is methyl, i.e., the synthesis of TDMSM. TIFF0007683037000004.tif43170TDMSM Scheme 2

[0032] The present invention can be further illustrated by the following examples of its specific embodiments, which are included for illustrative purposes only and are not intended to limit the scope of the present invention unless otherwise specified.

Examples

[0033] Example 1 - Synthesis of TDMSM Chloromethylsilane (80 g, 0.85 mol), bromoform (71.16 g, 0.28 mol), and magnesium (20.55 g, 0.85 mol) were placed in a 1 L three-necked round-bottom flask. The reaction mixture was reacted at room temperature. Since heat was generated during the reaction, after the reaction was completed, the temperature of the reaction mixture was cooled to room temperature. The product was purified by simple distillation at 9 torr and 53 °C, and the final product was obtained as a colorless liquid (13 g, 24%).

[0034] General procedure for deposition using TDMSM as oxidation gas together with ozone The silicon oxide film was deposited with tris(dimethylsilyl)methane placed in a bubbler at 25 - 40 °C. Using a double showerhead ALD reactor, while calibrating the wafer temperature to 450 °C - 650 °C with a thermocouple (TC) wafer, the silicon oxide film was deposited on the silicon wafer together with the ozone reactant, and the reactor pressure was controlled at 0.5 - 2.0 Torr. Following the silicon oxide deposition, a 21 - 28 second silicon pulse, a 15 - 40 second Ar purge, a 30 second ozone pulse, and a 15 - 40 second Ar purge were performed. This cycle was repeated 150 times to obtain a film thickness of 250 Å. At 650 °C, at approximately 1.8 Å / cycle, it was saturated without containing carbon and chlorine impurities in the film. Data at three different wafer temperatures are shown in Table 1 below. TIFF0007683037000005.tif33170

[0035] Example 3 - Method for measuring the wet etching rate (WER) of TDSM In the wet etching measurement process used in this specification, a 200:1 solution of 49% hydrofluoric acid (0.25 wt% diluted HF) was used. The thermal oxide layer was used as a reference. Typically, the wet etching rate (WER) of the thermal oxide with respect to 0.25 wt% diluted HF is about 0.23 Å / second. The silicon oxide layer was etched for 60 seconds by the etching process with diluted HF, and the WER was estimated from the thickness change before and after the wet etching. Figure 3 shows the relative WER of the silicon oxide films deposited at various wafer temperatures using TDSM and ozone, and BTBAS and ozone, with respect to the thermal oxide.

[0036] Although the present invention has been described in detail with particular reference to its specific embodiments, it will be understood that variations and modifications can be affected within the spirit and scope of the present invention.

Claims

1. A method for forming a silicon-containing film on the surface of a microelectronic device in a reaction region, comprising introducing the following into the reaction region under vapor deposition conditions, the silicon-containing film containing silicon dioxide, the method.

2. The method according to claim 1, wherein the silicon-containing film further comprises silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, silicon oxycarbonitride, a low dielectric constant silicon-containing thin film, a high dielectric constant gate silicate film or a low temperature silicon epitaxial film.

3. The vapor deposition conditions are H ２ 、H ２ plasma, H ２ / O ２ mixture, water, N ２ O, N ２ O plasma, NH ３ 、NH ３ plasma, N ２ or N ２ The method according to claim 1, comprising a gas selected from plasma.

4. The method according to claim 1, wherein the vapor deposition conditions include atomic layer deposition conditions using an oxidation gas selected from oxygen, oxygen plasma and ozone.

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