阅读说明：本技术 氮化硅膜蚀刻组合物 (Silicon nitride film etching composition ) 是由 金东铉 朴贤宇 李斗元 曺长佑 李明镐 宋明根 于 2019-06-17 设计创作，主要内容包括：本发明涉及一种氮化硅膜蚀刻组合物,更具体而言,通过在蚀刻组合物中包含两种彼此不同的硅系化合物,相比于氧化硅膜能够选择性地蚀刻氮化硅膜,其蚀刻选择比显著,在用于蚀刻工序和半导体制造工序时,可以在抑制发生析出物且减少存在于周围的包含氧化硅膜的其他膜的异常生长方面提供卓越的效果。(The present invention relates to a silicon nitride film etching composition, and more particularly, to a silicon nitride film etching composition which, when containing two different silicon compounds in the etching composition, can selectively etch a silicon nitride film compared to a silicon oxide film, has a remarkable etching selectivity, and when used in an etching step and a semiconductor manufacturing step, can provide an excellent effect of suppressing the occurrence of precipitates and reducing abnormal growth of other films including a silicon oxide film existing therearound.)

1. A silicon nitride film etching composition comprising phosphoric acid, a first silicon-based compound of the following chemical formula 1, a second silicon-based compound of the following chemical formula 2 and water,

[ chemical formula 1]

[ chemical formula 2]

In the chemical formula 1 and the chemical formula 2,

R¹to R⁶Each independently selected from hydrogen, halogen, hydroxy, (C1-C10) alkoxy, (C1-C10) alkyl, and (C2-C10) alkenyl;

r' is substituted or unsubstituted amino (C1-C10) alkyl, the alkyl-CH₂Can be-N (R)¹¹) -or-O-substitution, said R¹¹Is hydrogen, (C1-C10) alkyl or amino (C1-C10) alkyl;

r' is selected from substituted or unsubstituted-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, said L₁To L₅Each independently is (C1-C10) alkylene or (C3-C10) cycloalkylene¹²To R¹⁶Each independently hydrogen or (C1-C10) alkyl;

the substitution comprises one or more selected from the group consisting of halogen, hydroxy, cyano, nitro, (C1-C10) alkyl, (C1-C10) alkoxy, (C3-C10) cycloalkyl, (C3-C10) heterocycloalkyl, (C3-C12) heteroaryl, and (C6-C12) aryl, the heterocycloalkyl or heteroaryl comprising one or more selected from the group consisting of B, N, O, S, P (═ O), Si, and P.

2. The silicon nitride film etching composition according to claim 1, wherein, in the chemical formula 1 and the chemical formula 2,

the R is¹To R⁶Each independently selected from halogen, hydroxy, (C1-C7) alkoxy, (C1-C7) alkyl, and (C2-C7) alkenyl, said R¹To R³At least one substituent of (1) and said R⁴To R⁶At least one substituent of (a) is hydroxyl or (C1-C7) alkoxy;

r' is-L₁₁-(A-L₁₂)_a-NR²¹R²²Said L is₁₁And L₁₂Each independently being (C1-C7) alkylene, said R²¹And R²²Each independently hydrogen, (C1-C7) alkyl or amino (C1-C7) alkyl, A is-N (R)¹¹) -or-O-, said R¹¹Is hydrogen, (C1-C7) alkyl or amino (C1-C7) alkyl, a is an integer of 0 to 6, and when a is an integer of 2 or more, each structural unit may be different from each other;

said R' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, said L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene¹²To R¹⁶Each independently hydrogen or (C1-C7) alkyl.

3. The silicon nitride film etching composition according to claim 1, wherein, in the chemical formula 1 and the chemical formula 2,

the R is¹To R⁶Each independently is hydroxy or (C1-C7) alkoxy;

r' is-L₁₁-NR²¹R²²Said L is₁₁Is (C1-C7) alkylene, the R²¹And R²²Each independently hydrogen or (C1-C7) alkyl;

said R' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, said L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene¹²To R¹⁶Each independently hydrogen or (C1-C7) alkyl.

4. The silicon nitride film etching composition according to claim 1, wherein, in the chemical formula 1 and the chemical formula 2,

the R is¹To R⁶Each independently is hydroxy or (C1-C7) alkoxy;

r' is-L₁₁-(N(R¹¹)-L₁₂)_a-NR²¹R²²Said L is₁₁And L₁₂Each independently being (C1-C7) alkylene, said R²¹And R²²Each independently hydrogen or (C1-C7) alkyl, the R¹¹Is hydrogen, (C1-C7) alkyl, a is an integer from 1 to 3;

said R' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, said L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene¹²To R¹⁶Each independently hydrogen or (C1-C7) alkyl.

5. The silicon nitride film etching composition according to claim 1, wherein the first silicon-based compound is at least one selected from the group consisting of compounds of the following chemical formulae 3 to 5,

[ chemical formula 3]

[ chemical formula 4]

[ chemical formula 5]

In the chemical formulae 3 to 5,

R³¹to R³³Each independently is hydroxy or (C1-C3) alkoxy;

R⁴¹、R⁴²、R⁴⁴and R⁴⁵Each independently hydrogen or (C1-C3) alkyl;

R⁴³is (C1-C3) alkyl;

a. d and e are each independently an integer from 1 to 5;

c and b are each independently an integer from 2 to 4.

6. The silicon nitride film etching composition according to claim 1, wherein the second silicon-based compound is at least one selected from the group consisting of compounds of the following chemical formula 6,

[ chemical formula 6]

In the chemical formula 6, the first and second organic solvents,

R³⁴to R³⁶Each independently is hydroxy or (C1-C3) alkoxy;

r' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, said L₁To L₅Each independently being (C1-C7) alkylene, said R¹²To R¹⁶Each independently hydrogen or (C1-C3) alkyl;

f is an integer of 1 to 5.

7. The silicon nitride film etching composition according to claim 1, wherein the molar ratio of the substituent groups R': R ″ of the first silicon-based compound and the second silicon-based compound is a ratio of 1:0.01 to 1: 1.

8. The silicon nitride film etching composition of claim 1, comprising, relative to the total weight of the silicon nitride film etching composition: 60 to 95 weight percent phosphoric acid; 0.01 to 10% by weight of the total of the first silicon-based compound and the second silicon-based compound; and the balance water.

9. The silicon nitride film etching composition according to claim 1, wherein the silicon nitride film etching composition contains the first silicon-based compound and the second silicon-based compound in a weight ratio of 1:1 to 100: 1.

10. The silicon nitride film etching composition according to claim 1, wherein the silicon nitride film etching composition further comprises a fluorine-based compound.

11. The silicon nitride film etching composition of claim 1, wherein the silicon nitride film etching composition has an etching rate of 100 to 100 for a silicon nitride filmThe etching rate of the silicon oxide film is 0 to

12. The silicon nitride film etching composition according to claim 1, wherein the silicon nitride film etching composition has a silicon nitride film/silicon oxide film etching selectivity of 500 or more.

13. The silicon nitride film etching composition according to claim 1, wherein the etching rate decrease rate of the silicon nitride film after the repeated etching process satisfies the following relational expression 1,

[ relational expression 1]

△ERD_SiNx≤1％

In the above-mentioned relation 1, the first and second,

△ERD_SiNxis an etching rate reduction rate for the silicon nitride film with respect to the initial etching rate.

14. A method for etching a silicon nitride film selectively compared to a silicon oxide film, using the silicon nitride film etching composition according to any one of claims 1 to 13.

15. A method for suppressing abnormal growth of a silicon oxide film, which utilizes the silicon nitride film etching composition according to any one of claims 1 to 13.

16. A method for manufacturing a semiconductor device, comprising an etching process carried out using the silicon nitride film etching composition according to any one of claims 1 to 13.

Technical Field

The present invention relates to a silicon nitride film etching composition, and more particularly, to an etching composition for a silicon nitride film, which can etch a silicon nitride film at a higher selectivity ratio than a silicon oxide film by including two different silicon-based compounds in the etching composition, an etching method for a silicon nitride film using the etching composition, a method for suppressing abnormal growth of a silicon oxide film, and a method for manufacturing a semiconductor device.

Background

Silicon oxide film (SiO)₂) And a silicon nitride film (SiN)_x) Is a typical insulating film used in a semiconductor manufacturing process. Wherein the silicon nitride film is used as a cap layer, a spacer layer, or a hard mask layer in a semiconductor device. The silicon oxide film and the silicon nitride film are used alone, or one or more silicon oxide films and one or more silicon nitride films are alternately stacked.

Etching of silicon nitride films is accomplished at high temperatures around 160 c using a mixture of high purity phosphoric acid and deionized water. However, high-purity phosphoric acid has a problem that the etching selectivity of a silicon nitride film to a silicon oxide film is low, and it is difficult to apply the phosphoric acid to a stacked structure of a silicon nitride film and a silicon oxide film. Further, since the silicon nitride film etching composition containing phosphoric acid is continuously concentrated by Water evaporation at a high temperature, and the etching rate of the nitride film and the oxide film is affected, it is necessary to continuously supply pure Water (Deionized Water). However, there are the following problems: even a slight change in the amount of pure water supplied causes a problem in removing the silicon nitride film, and phosphoric acid itself is a strong acid and corrosive, and therefore is not easy to handle.

In order to solve the above problems and to improve the etching selectivity of the silicon nitride film with respect to the silicon oxide film, a silicon nitride film etching composition in which silicic acid is dissolved in phosphoric acid can be used. However, the above silicon nitride film etching composition has the following problems: when etching is performed, a problem of abnormal growth (abnormal growth) occurs in which precipitates are generated and the thickness of the silicon oxide film is conversely increased, and thus it is difficult to apply the method to the process.

In addition, although a method of controlling the etching selectivity using a silicon compound containing oxygen atoms directly bonded to silicon can be used, the etching selectivity of a silicon nitride film to a silicon oxide film is not high, and silicic acid generated during etching of the silicon nitride film still induces abnormal growth, which causes various problems in a post-process.

Disclosure of Invention

Technical problem

The purpose of the present invention is to provide a silicon nitride film etching composition that contains phosphoric acid, two different silicon-based compounds, and water and has a high etching selectivity for a silicon nitride film.

Another object of the present invention is to provide a stable silicon nitride film etching composition which is less likely to cause a change in the etching rate and the etching selectivity of a silicon nitride film even when the etching treatment time is increased or repeated.

Another object of the present invention is to provide a silicon nitride film etching composition which does not generate precipitates and does not cause abnormal growth of a silicon oxide film during etching.

Another object of the present invention is to provide a method for etching a silicon nitride film using the silicon nitride film etching composition and a method for manufacturing a semiconductor device.

Another object of the present invention is to provide a method for suppressing abnormal growth of a silicon oxide film using the silicon nitride film etching composition.

Technical scheme

In order to solve the above problems, a silicon nitride film etching composition is provided, which comprises phosphoric acid, a first silicon compound of the following chemical formula 1, a second silicon compound of the following chemical formula 2, and water.

[ chemical formula 1]

[ chemical formula 2]

[ in the above-mentioned chemical formulas 1 and 2,

R¹to R⁶Each independently selected from hydrogen, halogen, hydroxy, (C1-C10) alkoxy, (C1-C10) alkyl, and (C2-C10) alkenyl;

r' is substituted or unsubstituted amino (C1-C)10) Alkyl, -CH of said alkyl₂May be-N (R)¹¹) or-O-substitution, above R¹¹Is hydrogen, (C1-C10) alkyl or amino (C1-C10) alkyl;

r' is selected from substituted or unsubstituted-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、 -L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C10) alkylene or (C3-C10) cycloalkylene, R¹²To R¹⁶Each independently hydrogen or (C1-C10) alkyl;

the above-mentioned substitution includes one or more selected from the group consisting of halogen, hydroxy, cyano, nitro, (C1-C10) alkyl, (C1-C10) alkoxy, (C3-C10) cycloalkyl, (C3-C10) heterocycloalkyl, (C3-C12) heteroaryl, and (C6-C12) aryl, and the above-mentioned heterocycloalkyl or heteroaryl includes one or more selected from the group consisting of B, N, O, S, P (═ O), Si, and P ].

In the above chemical formulas 1 and 2, the above R¹To R⁶Each independently selected from the group consisting of halogen, hydroxy, (C1-C7) alkoxy, (C1-C7) alkyl, and (C2-C7) alkenyl, R as defined above¹To R³At least one substituent of (1) and the above-mentioned R⁴To R⁶At least one substituent of (a) is hydroxyl or (C1-C7) alkoxy; r' is-L₁₁-(A-L₁₂)_a-NR²¹R²²Above L₁₁And L₁₂Each independently is (C1-C7) alkylene, R above²¹And R²²Each independently hydrogen, (C1-C7) alkyl or amino (C1-C7) alkyl, wherein A is-N (R)¹¹) -or-O-, R as defined above¹¹Is hydrogen, (C1-C7) alkyl or amino (C1-C7) alkyl, the above a is an integer of 0 to 6, and when the above a is an integer of 2 or more, each structural unit may be different from each other; r' is selected from-L₁-SO₃H、 -L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、 -L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene, R¹²To R¹⁶Each independently may be hydrogen or (C1-C7) alkyl.

In the above chemical formulas 1 and 2, the above R¹To R⁶Each independently is hydroxy or (C1-C7) alkoxy; r' is-L₁₁-NR²¹R²²Above L₁₁Is (C1-C7) alkylene, R is as defined above²¹And R²²Each independently hydrogen or (C1-C7) alkyl; r' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、 -L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene, R¹²To R¹⁶Each independently may be hydrogen or (C1-C7) alkyl.

In the above chemical formulas 1 and 2, the above R¹To R⁶Each independently is hydroxy or (C1-C7) alkoxy; r' is-L₁₁-(N(R¹¹)-L₁₂)_a-NR²¹R²²Above L₁₁And L₁₂Each independently is (C1-C7) alkylene, R above²¹And R²²Each independently is hydrogen or (C1-C7) alkyl, R is¹¹Is hydrogen, (C1-C7) alkyl, a is an integer of 1 to 3; r' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、 -L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene, R¹²To R¹⁶Each independently may be hydrogen or (C1-C7) alkyl.

The silicon nitride film etching composition may include at least one or more first silicon-based compounds selected from the group consisting of compounds of the following chemical formulas 3 to 5.

[ chemical formula 3]

[ chemical formula 4]

[ chemical formula 5]

[ in the above chemical formulas 3 to 5,

R³¹to R³³Each independently is hydroxy or (C1-C3) alkoxy;

R⁴¹、R⁴²、R⁴⁴and R⁴⁵Each independently hydrogen or (C1-C3) alkyl;

R⁴³is (C1-C3) alkyl;

a. d and e are each independently an integer from 1 to 5;

c and b are each independently an integer from 2 to 4. ]

The silicon nitride film etching composition may include at least one second silicon-based compound selected from the compounds of the following chemical formula 6.

[ chemical formula 6]

[ in the above-mentioned chemical formula 6,

R³⁴to R³⁶Each independently is hydroxy or (C1-C3) alkoxy;

r' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、 -L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C7) alkylene, R above¹²To R¹⁶Each independently hydrogen or (C1-C3) alkyl;

f is an integer of 1 to 5 ].

The molar ratio of the substituent R 'to R' of the first silicon-based compound and the second silicon-based compound may be in the range of 1:0.01 to 1: 1.

The silicon nitride film etching composition comprises, based on the total weight of the silicon nitride film etching composition: 60 to 95 weight percent phosphoric acid; 0.01 to 10% by weight of the total of the first silicon-based compound and the second silicon-based compound; and the balance water.

The silicon nitride film etching composition may contain the first silicon-based compound and the second silicon-based compound in a weight ratio of 1:1 to 100: 1.

The silicon nitride film etching composition may further contain a fluorine-based compound.

With respect to the above silicon nitride film etching composition, the etching rate of the above silicon nitride film etching composition with respect to the silicon nitride film may be 100 toThe etching rate for the silicon oxide film may be 0 to

The silicon nitride film etching composition may have a silicon nitride film/silicon oxide film etching selectivity of 500 or more.

The silicon nitride film etching composition can satisfy the following relational expression 1 in terms of the rate of decrease in the etching rate of the silicon nitride film after repeated etching steps.

[ relational expression 1]

△ERD_SiNx≤1％

In the above-mentioned relation 1, the first,

△ERD_SiNxis an etching rate reduction rate for the silicon nitride film with respect to the initial etching rate.

Provided is a method for etching a silicon nitride film selectively to a silicon nitride film, using the above silicon nitride film etching composition.

Provided is a method for suppressing abnormal growth of a silicon oxide film, which uses the above silicon nitride film etching composition.

A method for manufacturing a semiconductor device is provided, which comprises an etching step carried out using the silicon nitride film etching composition.

Advantageous effects

The silicon nitride film etching composition according to the present invention has the effect of being able to selectively etch a silicon nitride film compared to a silicon oxide film, and of being significantly excellent in etching selectivity.

Further, the silicon nitride film etching composition according to the present invention has the effect of reducing the variation in the etching rate and the etching selectivity ratio with respect to the silicon nitride film even if the etching treatment time is increased or repeatedly used, and thus can ultimately improve the productivity in the semiconductor manufacturing process for selectively etching the silicon nitride film.

Further, the silicon nitride film etching composition according to the present invention is excellent in storage stability, and can maintain a constant etching rate and etching selectivity ratio for a silicon nitride film even when used or stored for a long time.

The silicon nitride film etching composition of the present invention is excellent in the effect of suppressing the generation of precipitates and reducing abnormal growth of other films including a silicon oxide film existing therearound when used in an etching step and a semiconductor manufacturing step.

Detailed Description

The present invention will be described in more detail below with reference to specific examples and examples. However, the following specific examples and examples are merely illustrative of the present invention in detail, and the present invention is not limited thereto and can be realized in various forms.

In addition, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the present invention, terms used in the description are only for effectively describing specific embodiments and are not intended to limit the present invention.

Furthermore, as used in the specification and the appended claims, the singular forms "a", "an", and "the" may be intended to include the plural forms as long as they are not specifically referred to in the context.

The term "etching selectivity ratio (E) in the present specification_SiNx/E_SiO2) "means the etching rate (E) of the silicon nitride film_SiNx) Etch rate with silicon oxide (E)_SiO2) The ratio of. In addition, when the etching rate of the silicon oxide film is almost close to 0 or the value of the etching selectivity is large, it means that the silicon nitride film can be selectively etched.

The term "change in etching selectivity" in the present specification means an absolute value of a difference between an initial etching selectivity and an etching selectivity when an etching process is repeated 2 or more times using the same silicon nitride film etching composition.

The term "Etch rate drift (Δ ERD)" used herein means a rate of change in the etching rate from the initial etching rate when the etching process is repeated 2 or more times using the same silicon nitride film etching composition. In general, the etching capability, that is, the etching rate tends to decrease as the etching process is repeatedly performed, and therefore, the rate of change is defined as a decrease rate, and the same meaning is also understood. Specifically, the etching rate reduction rate can be derived from the following formula 1.

[ formula 1]

Δ ERD (%) ([ 1- { (etching rate when etching process is repeated n times or more)/(initial etching rate) } × 100

The unit used in the present specification without particularly referring to the unit is based on weight, for example,% or ratio unit means wt% or wt ratio, and in terms of wt%, unless otherwise defined, means the weight% of any component in the entire composition in the composition.

The terms "alkyl" and "alkoxy" in this specification include straight or branched chain forms.

The term "alkylene" in the present specification means a 2-valent substituent in which one hydrogen is removed from the above-mentioned alkyl group.

The term "alkenyl" in this specification refers to a 1-valent substituent derived from a hydrocarbon in a straight or branched chain configuration containing more than one double bond.

The term "aminoalkyl" in the present description means — (alkylene) -NH₂。

The term "cycloalkyl" in this specification refers to a non-aromatic monocyclic (or polycyclic) ring system having 3 to 30 carbon atoms, the monocyclic ring including, without limitation, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. Examples of polycyclic cycloalkyl groups include perhydronaphthyl, perhydroindenyl, and the like; the bridged polycyclic cycloalkyl group includes adamantyl and norbornenyl groups and the like.

The term "cycloalkylene" in the present specification means a 2-valent substituent in which one hydrogen is removed from the above cycloalkyl group.

The term "heterocycloalkyl group" in the present specification means a substituted or unsubstituted non-aromatic 3 to 15-membered ring system substituent formed of a carbon atom and 1 to 5 hetero atoms selected from nitrogen, phosphorus, oxygen, sulfur and the like, the heterocycloalkyl radical may be a monocyclic, bicyclic or tricyclic ring system which may contain a fused, bridged or spiro ring system, and the nitrogen, phosphorus, carbon, oxygen, sulfur atom and the like in the heterocycloalkyl radical may be oxidized in various oxidation states as the case may be. In addition, the nitrogen atoms may be quaternized as the case may be.

The term "aryl" in the present specification is a substituent formed by removing one hydrogen from an aromatic hydrocarbon by removing one hydrogen, and includes a single ring system or a fused ring system containing suitably 4 to 7, preferably 5 or 6 ring atoms on each ring, and also includes a form in which a plurality of aryl groups are connected by a single bond. Specific examples include, but are not limited to, phenyl, naphthyl, biphenyl, anthryl, indenyl, fluorenyl, and the like.

The term "heteroaryl" as used herein means an aryl group containing 1 to 4 heteroatoms selected from B, N, O, S, P (═ O), Si, and P as aromatic ring skeleton atoms, and the remaining aromatic ring skeleton atoms are carbon, and is a polycyclic heteroaryl group formed by condensing a 5-to 6-membered monocyclic heteroaryl group with one or more benzene rings, and may be partially saturated. The heteroaryl group in the present specification also includes a form in which at least one heteroaryl group is connected by a single bond.

The term "halogen" in the present specification means a fluorine, chlorine, bromine or iodine atom or the like.

Silicon nitride films and silicon oxide films are typical insulating films used in semiconductor manufacturing processes. In the semiconductor process, a silicon nitride film is deposited mainly by a Chemical Vapor Deposition (CVD) process as a structure in contact with a silicon oxide film, a polysilicon film, a silicon wafer surface, and the like, and is removed by etching.

The conventional wet etching has a problem that the etching selectivity of a silicon nitride film to a silicon oxide film is lowered and the etching selectivity is changed when an etching solution is used a plurality of times. In addition, there is a problem that precipitates are generated during etching and the thickness of the silicon oxide film increases.

Thus, the present inventors have conducted intensive studies on a silicon nitride film etching composition having a further improved etching selectivity ratio while solving the above-mentioned problems. As a result, it was found that when a composition containing phosphoric acid and two different silicon compounds was used for the treatment, the etching selectivity of the silicon nitride film with respect to the silicon oxide film was excellent, and the abnormal growth was reduced.

Further, it was found that the silicon nitride film etching composition according to the present invention exhibits excellent etching selectivity of a silicon nitride film with respect to a silicon oxide film and exhibits high stability, thereby maintaining an etching rate and an etching selectivity ratio for the silicon nitride film for a long time even if the treatment time and the number of treatments are increased, thereby completing the present invention.

The silicon nitride film etching composition according to the present invention is specifically described below.

The silicon nitride film etching composition according to an embodiment of the present invention may include phosphoric acid, a first silicon-based compound of the following chemical formula 1, a second silicon-based compound of the following chemical formula 2, and water.

[ chemical formula 1]

[ chemical formula 2]

[ in the above-mentioned chemical formulas 1 and 2,

R¹to R⁶Each independently selected from hydrogen, halogen, hydroxy, (C1-C10) alkoxy, (C1-C10) alkyl, and (C2-C10) alkenyl;

r' is substituted or unsubstituted amino (C1-C10) alkyl, -CH of said alkyl₂May be-N (R)¹¹) or-O-substitution, above R¹¹Is hydrogen, (C1-C10) alkyl or amino (C1-C10) alkyl;

r' is selected from substituted or unsubstituted-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、 -L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C10) alkylene or (C3-C10) cycloalkylene, R¹²To R¹⁶Each independently hydrogen or (C1-C10) alkyl;

the above-mentioned substitution includes one or more selected from the group consisting of halogen, hydroxy, cyano, nitro, (C1-C10) alkyl, (C1-C10) alkoxy, (C3-C10) cycloalkyl, (C3-C10) heterocycloalkyl, (C3-C12) heteroaryl, and (C6-C12) aryl, and the above-mentioned heterocycloalkyl or heteroaryl includes one or more selected from the group consisting of B, N, O, S, P (═ O), Si, and P ].

In the first silicon compound of the above chemical formula 1, R is¹To R³Each independently selected from the group consisting of halogen, hydroxy, (C1-C7) alkoxy, (C1-C7) alkyl, and (C2-C7) alkenyl, R as defined above¹To R³At least one substituent of (a) is hydroxyl or (C1-C7) alkoxy; r' is-L₁₁-(A-L₁₂)_a-NR²¹R²²Above L₁₁And L₁₂Each independentlyIs (C1-C7) alkylene, R is as defined above²¹And R²²Each independently hydrogen, (C1-C7) alkyl or amino (C1-C7) alkyl, wherein A is N (R)¹¹) -or-O-, R as defined above¹¹Is hydrogen, (C1-C7) alkyl or amino (C1-C7) alkyl, and a is an integer of 0 to 6, and when a is an integer of 2 or more, each structural unit may be different from each other.

In the first silicon compound of the above chemical formula 1, R is¹To R³Each independently is hydroxy or (C1-C7) alkoxy; r' is-L₁₁-NR²¹R²²Above L₁₁Is (C1-C7) alkylene, R is as defined above²¹And R²²Each independently may be hydrogen or (C1-C7) alkyl.

In the first silicon compound of the above chemical formula 1, R is¹To R³Each independently is hydroxy or (C1-C7) alkoxy; r' is-L₁₁-(N(R¹¹)-L₁₂)_a-NR²¹R²²Above L₁₁And L₁₂Each independently is (C1-C7) alkylene, R above²¹And R²²Each independently is hydrogen or (C1-C7) alkyl, R is¹¹Is hydrogen or (C1-C7) alkyl, and a may be an integer of 1 to 3.

Specifically, the first silicon-based compound may be at least one selected from the group consisting of compounds of the following chemical formulas 3 to 5.

[ chemical formula 3]

[ chemical formula 4]

[ chemical formula 5]

[ in the above chemical formulas 3 to 5,

R³¹to R³³Each independently is hydroxy or (C1-C3) alkoxy;

R⁴¹、R⁴²、R⁴⁴and R⁴⁵Each independently hydrogen or (C1-C3) alkyl;

R⁴³is (C1-C3) alkyl;

a. d and e are each independently an integer from 1 to 5;

c and b are each independently an integer of 2 to 4 ].

More specifically, the first silicon compound may be selected from (3-aminopropyl) silanetriol, N- (2-aminoethyl) - (3-aminopropyl) trimethoxysilane, (3-trimethoxysilylpropyl) diethylenetriamine, 4-amino-3, 3-dimethylbutyltrimethoxysilane, N-dimethyl-3-aminopropyl) trimethoxysilane, and the like.

In the second silicon compound of the above chemical formula 2, R is⁴To R⁶Each independently selected from the group consisting of halogen, hydroxy, (C1-C7) alkoxy, (C1-C7) alkyl, and (C2-C7) alkenyl, R as defined above⁴To R⁶At least one substituent of (a) is hydroxyl or (C1-C7) alkoxy; r' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、 -L₃-P(＝O)(OR¹²)(OR¹³)、-L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene, R¹²To R¹⁶Each independently may be hydrogen or (C1-C7) alkyl.

The salt may be a salt of an alkali metal such as sodium or potassium, but is not limited thereto as long as it is a salt generally used in the art.

In the second silicon compound of the above chemical formula 2, R is⁴To R⁶Each independently is hydroxy or (C1-C7) alkoxy; r' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、 -L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C7) alkylene or (C3-C7) cycloalkylene, R¹²To R¹⁶Each independently may be hydrogen or (C1-C7) alkyl.

Specifically, the second silicon-based compound may be at least one selected from the compounds of chemical formula 6 below.

[ chemical formula 6]

[ in the above-mentioned chemical formula 6,

R³⁴to R³⁶Each independently is hydroxy or (C1-C3) alkoxy;

r' is selected from-L₁-SO₃H、-L₂-OP(＝O)(OH)₂、-L₃-P(＝O)(OR¹²)(OR¹³)、 -L₄-OP(＝O)(OH)(R¹⁴)、-L₅-P(＝O)(OR¹⁵)R¹⁶And salts thereof, the above-mentioned L₁To L₅Each independently is (C1-C7) alkylene, R above¹²To R¹⁶Each independently hydrogen or (C1-C3) alkyl;

f is an integer of 1 to 5 ].

More specifically, the second silicon-based compound may be selected from 3- (trihydroxysilyl) -1-propanesulfonic acid (3- (trihydroxysilyl) -1-propanesulfonic acid), 3- (trihydroxysilyl) propylmethylphosphonate monosodium salt (3- (trihydroxysilyl) propylmethylphosphonate monomer salt), diethylphosphorylethyltriethoxysilane (diethylphosphoryltriethyloxysilane), and [2- (trihydroxysilyl)) ethyl ] phosphonic acid ([2- (trihydroxysilyl) ethyl ] phosphonic acid).

In the silicon nitride film etching composition according to an embodiment of the present invention, the cationic group of the first silicon compound is contained at a higher molar ratio than the anionic group of the second silicon compound in view of an excellent silicon nitride film/silicon oxide film etching selectivity and effective suppression of precipitates and abnormal growth generated in an etching process.

For example, the molar ratio of the cationic group of the first silicon-based compound to the anionic group of the second silicon-based compound may be in the range of 1:0.01 to 1:1, specifically 1:0.05 to 1:1, and more specifically 1:0.1 to 1: 1.

In addition, the silicon nitride film etching composition according to an embodiment of the present invention may include, relative to the total weight of the silicon nitride film etching composition: 60 to 95 weight percent phosphoric acid; 0.01 to 10% by weight of the total of the first silicon-based compound and the second silicon-based compound; and the balance water.

Specifically, the silicon nitride film etching composition may include: 60 to 90 weight percent phosphoric acid; 0.05 to 10% by weight of the total of the first silicon-based compound and the second silicon-based compound; and the balance of water, more specifically, the silicon nitride film etching composition may include: phosphoric acid 75 to 90 wt%; 0.05 to 5% by weight of the total of the first silicon-based compound and the second silicon-based compound; and the balance water.

That is, when the silicon nitride film etching composition satisfying the above range is used in the etching step, an effect of etching the silicon nitride film with high etching selectivity is exhibited, and even after repeated etching steps, excellent etching rate and high etching selectivity for the silicon nitride film can be maintained, and there is no inconvenience in the etching step, so that it is preferable.

Specifically, in the silicon nitride film etching composition, the first silicon compound (a) may be used in an excess amount compared to the second silicon compound (b) in order to provide a significant effect.

For example, the silicon nitride film etching composition may contain the first silicon-based compound (a) and the second silicon-based compound (b) at a weight ratio (a: b) of 1:1 to 100: 1.

For example, the above weight ratio (a: b) may be 1:1 to 70: 1.

For example, the above weight ratio (a: b) may be 1:1 to 50: 1.

In addition, the silicon nitride film etching composition according to an embodiment of the present invention may further include a fluorine-based compound.

When the fluorine-based compound is added, the rate of the silicon nitride film can be increased, and changes in the etching rate and etching selectivity of the silicon nitride film can be reduced even when the silicon nitride film is repeatedly used.

The fluorine-based compound may be one or a mixture of two or more selected from Hydrogen fluoride (Hydrogen fluoride), Ammonium fluoride (Ammonium fluoride), Ammonium bifluoride (Ammonium bifluoride), Tetrafluoroboric acid (Tetrafluoroboric acid), and the like.

For example, the fluorine-based compound may be contained in an amount of 0.001 to 2 wt%, specifically, 0.005 to 1 wt%, and more specifically, 0.01 to 0.1 wt%, based on the total weight of the silicon nitride film etching composition.

In addition, the silicon nitride film etching composition according to an embodiment of the present invention may further include an alcohol-based solvent. Thus, the viscosity of the silicon nitride film etching composition is adjusted, and therefore, a stable effect can be obtained even at a high temperature in a semiconductor manufacturing process. Further, when the silicon nitride film etching composition is used a plurality of times, the rate of change of the etching rate with respect to the silicon nitride film is low, and the process efficiency is excellent.

The alcohol solvent may be one or a mixture of two or more selected from methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tert-butanol, pentanol, hexanol, heptanol, octanol, and tetrahydrofurfuryl alcohol (THFA).

For example, the alcohol-based solvent may be contained in an amount of 0.05 to 10 wt%, specifically, 0.05 to 5 wt%, and more specifically, 0.05 to 3 wt%, based on the total weight of the silicon nitride film etching composition.

The water is not particularly limited, and specifically may be deionized water, more specifically deionized water for semiconductor processes having a resistivity value of 18M Ω · cm or more.

In addition, the silicon nitride film etching composition according to an embodiment of the present invention may further include any additive generally used in the art. The additive may contain any one or two or more selected from a surfactant, an antioxidant, an anticorrosive agent and the like, and it is needless to say that various additives may be used.

For example, the above additives may be used in an amount of 0.01 to 2 wt% based on the total weight of the silicon nitride film etching composition, respectively, but are not limited thereto.

The silicon nitride film etching composition according to an embodiment of the present invention is not only excellent in etching rate of a silicon nitride film but also excellent in etching selectivity of a silicon nitride film with respect to a silicon oxide film.

For example, the etching rate of the above silicon nitride film etching composition for a silicon nitride film may be 100 toThe etching rate for the silicon oxide film may be 0 to

For example, the etching rate of the above silicon nitride film etching composition for a silicon nitride film may be 130 toThe etching rate for the silicon oxide film may be 0 to

For example, the etching rate of the silicon nitride film etching composition for a silicon nitride film may be 150 to 150For theThe etching rate of the silicon oxide film may be 0.05 to

For example, the etching rate of the silicon nitride film etching composition for a silicon nitride film may be 150 to 150The etching rate for the silicon oxide film may be 0.05 to

For example, the silicon nitride film/silicon oxide film etching selectivity ratio (E) of the above silicon nitride film etching composition_SiNx/E_SiO2) May be 500 or more.

For example, the silicon nitride film/silicon oxide film etching selectivity ratio (E) of the above silicon nitride film etching composition_SiNx/E_SiO2) And may range from 1,000 to 5,000.

For example, the silicon nitride film/silicon oxide film etching selectivity ratio (E) of the above silicon nitride film etching composition_SiNx/E_SiO2) And may range from 1,500 to 3,500.

In addition, the silicon nitride film etching composition according to an embodiment of the present invention may satisfy the following relational expression 1 in terms of the rate of decrease in the etching rate of the silicon nitride film after repeated etching processes.

[ relational expression 1]

△ERD_SiNx≤1％

[ in the above-mentioned relational expression 1,

△ERD_SiNxis an etching rate reduction rate for a silicon nitride film with respect to an initial etching rate]。

The silicon nitride film etching composition has excellent stability, and thus can obtain an effect of being stable even at a high temperature in a semiconductor manufacturing process. Further, even when the composition is used a plurality of times, the rate of change of the etching rate with respect to the silicon nitride film is low, and the process efficiency is excellent.

For example, etching of the silicon nitride filmRate of speed reduction (Δ ERD)_SiNx) May be 0.01 to 0.95%.

For example, the etching rate reduction rate (Δ ERD) of the silicon nitride film_SiNx) May be 0.1 to 0.9%.

Hereinafter, a method of using the silicon nitride film etching composition according to the present invention will be specifically described.

One mode of a method according to an embodiment of the present invention may be a method of etching a silicon nitride film selectively compared to a silicon oxide film.

Another mode may be a method of suppressing abnormal growth of the silicon oxide film.

Another embodiment may be a method for manufacturing a semiconductor device including an etching step of selectively etching a silicon nitride film.

The silicon nitride film may be a variety of silicon nitride films such as SiN film, SiON film, and doped SiN film (doped SiN layer). As a concept including such a silicon nitride film, specifically, a film quality mainly used as an insulating film in forming, for example, a gate electrode or the like can be mentioned. However, the present invention can be used without limitation as long as the present invention is applied to the technical field of etching a silicon nitride film selectively to a silicon oxide film.

Further, the silicon Oxide film is not limited as long as it is a silicon Oxide film generally used in the art, and may be, for example, a film selected from SOD (Spin On Dielectric), HDP (High Density Plasma), thermal Oxide (thermal Oxide), BPSG (borophosphosilicate Glass), PSG (phosphosilicate Glass), BSG (borophosphosilicate Glass, borosilicate Glass), PSZ (Polysilazane), FSG (Fluorinated Silicate Glass, fluorosilicone Glass), LP-tetraethyl orthosilicate, eosilicon Oxide (silicone Oxide), TEOS (Low Pressure tetraethyl orthosilicate), TEOS (silicone Oxide, TEOS), TEOS (High Temperature reinforced Silicate, TEOS), or a High Temperature Oxide (non-oxidized silicon Oxide), or a Low Temperature Oxide (non-oxidized silicon Oxide, a Low Temperature Oxide, or a Low Temperature Oxide, SOG (Spin On Glass) film, APL (Advanced planar)A ionization Layer) film, an ALD (Atomic Layer deposition) film, a PE-oxide (Plasma Enhanced oxide), and O₃-TEOS(O₃-Tetra Ethyl Ortho Silicate，O₃Tetraethyl orthosilicate), and the like. However, this is merely an example and is not limited thereto.

With the etching method using the silicon nitride film etching composition according to an embodiment of the present invention and the method for manufacturing a semiconductor device including the same, in the case where the above-mentioned silicon nitride film and silicon oxide film are present in a mixed manner, only the silicon nitride film can be selectively etched with respect to the silicon oxide film, the etching rate is high, and abnormal growth of films other than the silicon nitride film does not occur after etching, so that defective problems can be minimized in manufacturing a semiconductor device.

Further, the silicon nitride film etching composition according to the present invention has high temperature stability, thereby effectively suppressing the problem of phosphoric acid etching a silicon oxide film heated to a high temperature. Thus, abnormal growth of the silicon oxide film is not generated, substrate defects can be prevented, and the silicon nitride film can be selectively etched, thereby exhibiting excellent semiconductor device characteristics.

The method of etching a silicon nitride film selectively compared to a silicon nitride film and the method of suppressing abnormal growth of a silicon oxide film using the above-described silicon nitride film etching composition can be carried out according to methods generally used in the art.

For example, the impregnation method, the spray (spray) method, and the like can be used.

For example, the above method may be carried out at a process temperature of 100 ℃ or higher, specifically, 100 to 500 ℃, more specifically, 100 to 300 ℃.

In the above method, when a silicon oxide film, a silicon nitride film, a photoresist film, and the like formed on a substrate are present in a mixed state, only the silicon nitride film is etched selectively and rapidly with respect to the silicon oxide film, and not only is the generation of precipitates suppressed, but also abnormal growth of films other than the silicon nitride film can be reduced.

Various materials can be used for the substrate, and examples thereof include, but are not limited to, silicon, quartz, glass, silicon wafer, polymer, metal oxide, and the like. As examples of the polymer substrate, film substrates such as polyethylene terephthalate (pet), Polycarbonate (pc), polyimide (polyimide), polyethylene naphthalate (pet), and cyclic olefin polymer (cycloolefin) can be used, but the polymer substrate is not limited thereto.

The silicon oxide film, the silicon nitride film, and the photoresist film may each be formed as a single film, a double film, or a multiple film (multilayer film), and in the case of a double film or a multiple film, the order of lamination is not limited.

The method for manufacturing a semiconductor device including the etching step of selectively etching the silicon nitride film using the above-described silicon nitride film etching composition can also be carried out according to a method generally used in the art.

According to the above-described method for manufacturing a semiconductor device, in a semiconductor device in which a silicon nitride film and a silicon oxide film are alternately stacked or mixedly present, selective etching of the silicon nitride film can be realized, damage to the silicon oxide film can be effectively suppressed, damage to the silicon oxide film due to etching can be minimized, and stability, efficiency, and reliability of a semiconductor device manufacturing process can be greatly improved. In this case, the type of the semiconductor device is not particularly limited in the present invention.

Therefore, the method according to the present invention can remove a silicon nitride film selectively compared to a silicon oxide film, and can maintain the etching rate and the etching selectivity constant even if the processing time is increased, thereby being effectively applicable to a process required for selective etching of a silicon nitride film. In particular, the method according to the present invention has an excellent effect of suppressing the generation of precipitates and reducing abnormal growth of other films including a silicon oxide film existing therearound, and therefore, the stability and reliability of the process can be ensured.

The present invention will be described in more detail below based on examples and comparative examples. However, the following examples and comparative examples are only examples for illustrating the present invention in more detail, and the present invention is not limited to the following examples and comparative examples. In the present invention, the temperature unit means not specifically mentioned, and the amount unit of the composition used means weight% unless specifically mentioned.

(evaluation method)

1) Determination of etching Rate

Specifically, a silicon nitride film (SiN film) sheet and a silicon oxide film sheet are prepared by Chemical Vapor Deposition (CVD) in the same manner as in the semiconductor manufacturing process. As the silicon oxide membrane, PETEOS (Plasma Enhanced Tetra Ethyl Ortho Silicate) membrane was used.

The thickness of the composition before etching was measured using an Ellipsometer (Ellipsometer, J.A WOOLLAM, M-2000U) as a film thickness measuring apparatus. The sheet was immersed in a composition in which an etching temperature of 163 ℃ was maintained in a quartz bath (bath) for 10 minutes to perform an etching step. After the etching was completed, the substrate was washed with ultrapure water, and then the remaining etching solution and water were completely dried by a drying apparatus to measure the etching rate.

Regarding the etching rate, the difference between the thickness before etching and the thickness after etching was calculated by dividing the etching time (minutes) using an Ellipsometer (J.A WOOLLAM, M-2000U).

2) Determination of etching Rate decrease

The etching rate of the nitride film of the composition was measured by the above etching rate measuring method.

The etching process was carried out for 1 lot, and the etching rate reduction rate (. DELTA.ERD) was measured by repeating the use of the silicon nitride film etching composition without replacing the composition for etching for 10 lots_SiNx)。

Etching Rate (. DELTA.ERD)_SiNx(%)) was calculated from the following formula 1. In this case, the following initial etching rate was an etching rate in 1 etching step.

[ formula 1]

Δ ERD (%) ([ 1- { (etching rate when the etching process is repeated n times or more)/(initial etching rate) } × 100

3) Level of abnormal growth of oxide filmMeasurement of

The difference between the thickness of the composition before etching and the thickness after etching was measured using an Ellipsometer (J.A WOOLLAM, M-2000U) as a film thickness measuring apparatus. At this time, the difference in thickness of the thin film before and after etching was evaluated as an abnormal growth thickness.

(examples 1 to 9 and comparative examples 1 to 8)

The silicon nitride film etching compositions were prepared by mixing the components in the composition ratios shown in table 1 below, and then stirring the mixture at a speed of 500rpm for 5 minutes at normal temperature. The water content is set as the balance to 100% by weight of the total composition.

(Table 1)

(Table 2)

(Table 3)

As shown in tables 2 and 3, the silicon nitride film etching compositions according to the present invention each had an excellent etching selectivity of 1000 or more. Further, it was confirmed that even if the etching process was repeated and the silicon nitride film etching composition was reused a plurality of times, the reduction rate of the etching rate with respect to the silicon nitride film was remarkably low. It is particularly noted that in the case of all of the silicon nitride film etching compositions according to the present invention, abnormal growth of the silicon nitride film does not occur at all even if the etching process is repeatedly performed.

Specifically, it was confirmed that when the first silicon-based compound as in example 2 was used in the silicon nitride film etching composition according to the present invention, a significantly improved etching selectivity ratio could be achieved.

Specifically, it was confirmed that in the case where the silicon nitride film etching composition according to the present invention contains both the first silicon-based compound and the phosphorus (P) -containing second silicon-based compound, a more excellent rate of decrease in the etching rate of the silicon nitride film was exhibited.

On the other hand, in the case of the silicon nitride film etching compositions of each of comparative examples 1 to 8, the etching selectivity ratios were all less than 500, and were significantly reduced compared to the present example. In the case of the comparative example, when the etching process was repeated, the occurrence of abnormal growth of the silicon nitride film could not be suppressed.

In summary, according to the present invention, a silicon nitride film can be selectively etched with an excellent etching selectivity, and an initial etching capability can be maintained with a low rate of decrease in etching rate even when used many times, so that production efficiency can be significantly improved. In addition, the abnormal growth of the silicon oxide film can be effectively suppressed while minimizing the damage of the film quality of the silicon oxide film in the etching process, and therefore, a high-quality semiconductor device can be provided.

It will be apparent to those skilled in the art that the present invention is not limited to the above embodiments, and various substitutions, modifications and changes may be made without departing from the scope of the technical idea of the present invention.