KR20220078998A - Etchant composition for etching silicon and method of forming pattern using the same - Google Patents

Abstract

The silicone etchant composition of embodiments of the present invention includes an organic or inorganic alkali-based compound, a phosphite-based compound, and water. Since the silicon etchant composition includes a phosphite-based compound, it is possible to secure an etch selectivity to silicon during an etching process. A high uniformity pattern with reduced surface roughness can be formed by using the silicone etchant composition.

Description

Silicone etchant composition and pattern formation method using the same

The present invention relates to a silicone etchant composition and a pattern formation method using the same. More specifically, it relates to a silicone etchant composition including an alkali-based component and a pattern forming method using the same.

For example, in a semiconductor device such as a DRAM, a NAND flash memory device, a logic device, and the like, development to realize a large capacity while a critical dimension (CD) is rapidly decreased in recent years continues.

In the semiconductor device, for example, a silicon-based film or pattern such as polysilicon is widely used as a material for a gate electrode, a capacitor electrode, a conductive contact, a wiring, and the like. When a gate electrode or wiring is formed through direct etching of a metal film, it is difficult to form a pattern having a desired fine dimension due to a limitation in etch resolution. Accordingly, a process using a polysilicon film is being studied.

In order to perform a highly reliable semiconductor device process, it is required to secure a fast etch rate for a target to be removed and thus have excellent etch uniformity. However, when the etching process is performed, an increase in the etching rate of the object to be removed may promote etching of the protective layer.

Accordingly, it is required to develop an etchant composition for improving the etch selectivity while maintaining an excellent etch rate and etch uniformity for forming micro-dimensional patterns during the silicon film etch process.

For example, Korean Patent Application Laid-Open No. 10-2014-0177249 discloses an alkali-based etchant composition, but it is difficult to apply the etchant composition to simultaneously satisfy the etch rate and etch selectivity for the silicon film.

Korean Patent Publication No. 10-2014-0177249

One object of the present invention is to provide a silicone etchant composition that provides an improved etch rate and etch selectivity.

One object of the present invention is to provide a pattern forming method using the silicon etchant composition.

1. Organic or inorganic alkali-based compounds; phosphite-based compounds; and water, a silicone etchant composition.

2. The silicone etchant composition according to the above 1, wherein the organic alkali compound includes one of a quaternary alkyl ammonium salt compound, an azabicyclo compound, a diazabicyclo compound, and a triazabicyclo compound.

3. The above 2, wherein the quaternary alkyl ammonium salt compound is ammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, benzyl hydroxide A silicone etchant composition comprising at least one selected from the group consisting of triethylammonium, diethyldimethylammonium hydroxide and methyltributylammonium hydroxide.

4. The method of 1 above, wherein the inorganic alkali compound includes at least one selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and francium hydroxide, a silicon etchant composition.

5. The silicone etchant composition of 1 above, wherein the phosphite-based compound includes at least one of the compounds represented by the following Chemical Formulas 1 to 4:

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

(In Formulas 1 and 3, R ₁ , R ₂ , R ₃ , R ₇ and R ₈ are each independently an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, a phenyl group, a biphenyl group, a carbon number 7 to an alkylphenyl group having 16 or a silyl group having 1 to 10 carbon atoms,

R ₄ ⁺ , R ₅ ⁺ , R ₆ ⁺ , R ₉ ⁺ and R ₁₀ ⁺ in Formulas 2 and 4 are each independently a cation element or an ammonium cation).

6. The method of 1 above, wherein the phosphite-based compound is dimethyl phosphite, diethyl phosphite, diisopropyl phosphite, dibutyl phosphite, Diphenyl phosphite, Disodium hydrogen phosphite, Trimethyl phosphite, Triethyl phosphite, Tributyl phosphite, triisopropyl Phosphite (Triisopropyl phosphite), triphenyl phosphite (Triphenyl phosphite), tris (2-ethylhexyl) phosphite (Tris (2-ethylhexyl) phosphite), tris (nonylphenyl) phosphite (Tris (nonylphenyl) phosphite), Tris (trimethylsilyl) phosphite (Tris (trimethylsilyl) phosphite), dimethyl trimethylsilyl phosphite (Dimethyl trimethylsilyl phosphite), tris (1,1,1,3,3,3,-hexafluoro-2-propyl) Phosphite (Tris (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite), tris (2,2,2-trifluoroethyl) phosphite (Tris (2,2,2- trifluoroethyl) phosphite), tris (2,4-di-tert-butyl ethyl) phosphite (Tris (2,4-di-tert-butylphenyl) phosphite), triisodecyl phosphite, trisodium phosphite (Trisodium phosphite) and ammonium phosphite (Ammonium phosphite) comprising at least one selected from the group consisting of, a silicone etchant composition.

7. The silicone etchant composition of 1 above, further comprising a phosphate-based compound or a phosphonate-based compound

8. The method of 1 above, based on the total weight of the composition, 1 to 15% by weight of the organic or inorganic alkali compound; 0.1 to 5% by weight of the phosphite-based compound; and the remaining amount of water, a silicone etchant composition.

9. forming a dummy gate by etching the silicon film on the substrate; forming an oxide layer partially surrounding the dummy gate; and removing the dummy gate using an etchant composition comprising an organic or inorganic alkali compound, a phosphite compound, and a residual amount of water.

10. The method according to 9 above, further comprising the step of forming a gate structure in the opening from which the dummy gate is removed.

11. The method of 10 above, wherein the forming of the gate structure includes forming a barrier pattern and a metal gate sequentially stacked in the opening and including a metal nitride.

12. The method of 9 above, wherein the etchant composition further comprises a phosphate-based compound or a phosphonate-based compound.

The silicone etchant composition according to embodiments of the present invention may include an organic or inorganic alkali-based compound, a phosphite-based compound, and the remainder of water. The silicon etchant composition may provide an improved anticorrosive effect on the silicon oxide layer through the interaction between the phosphite-based compound and the silicon oxide layer.

In addition, the silicone etchant composition according to exemplary embodiments of the present invention may further include a phosphate-based compound or a phosphonate-based compound, thereby securing excellent selectivity with respect to the silicon film.

In addition, nanoscale semiconductor device patterns can be formed with high reliability by using the silicon etchant composition according to exemplary embodiments of the present invention.

1 to 5 are schematic cross-sectional views for explaining a pattern forming method according to example embodiments.

According to embodiments of the present invention, there is provided an etchant composition comprising an organic or inorganic alkali compound, a phosphite compound, and a residual amount of water and capable of etching silicon with an improved etch rate and excellent etch selectivity. In addition, a method for forming a pattern using the etchant composition is provided.

The etchant composition may be used in a silicon etching process for forming a gate electrode, a wiring, and a trench of a semiconductor device.

As used herein, the term “silicon” may refer to polysilicon and amorphous silicon.

Hereinafter, embodiments of the present invention will be described in detail.

<Silicone etchant composition>

The silicone etchant composition (hereinafter, may be abbreviated as etchant composition) according to exemplary embodiments may include an organic or inorganic alkali compound, a phosphite compound, and water.

The organic or inorganic alkali-based compound may serve as a main etchant for removing a target layer to be etched (eg, a silicon layer) during an etching process. For example, since the organic or inorganic alkali-based compound is dissociated in a solution to generate hydroxide ions, a silicon film to be removed may be etched.

According to exemplary embodiments, the organic alkali compound may include a quaternary alkyl ammonium salt compound, an azabicyclo compound, a diazabicyclo compound, and a triazabicyclo compound.

In some embodiments, the quaternary alkyl ammonium salt compound may include a quaternary alkyl ammonium hydroxide represented by Formula 5 below.

[Formula 5]

In Formula 5, R ₁ , R ₂ , R ₃ , and R ₄ may each independently represent an alkyl group or an aryl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. When the carbon number of R ₁ , R ₂ , R ₃ and R ₄ is within the above range, the hydroxide ion dissociation action of the quaternary alkyl ammonium compound may be excellent.

For example, the alkali compound is ammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, benzyltriethylammonium hydroxide, dihydroxide ethyldimethylammonium, methyltributylammonium hydroxide, and the like. These may be used alone or in combination of two or more.

In some embodiments, the azabicyclo compound may include azabicycloalkane or azabicycloalkene each having 3 to 13 carbon atoms, and the diazabicyclo compound each having 2 to 12 carbon atoms. It may include diazabicycloalkane or diazabicycloalkene, and the triazabicyclo compound may include triazabicycloalkane or triazabicycloalkene each having 2 to 11 carbon atoms.

For example, the organic alkali compound has a structure of one of azabicyclo-, diazabicyclo-, and triazabicyclo-, and depending on the number of carbon atoms and bonds, butane (- butane), pentane (-pentane), hexane (-hexane), heptane (-heptane), octane (-octane), nonane (-nonane), decane (-decane), undecane (-undecane), dodecane (- dodecane), tridecane (-tridecane), tetradecane (-tetradecane), nonene (-nonene), decene (-decene), may include one or more compounds selected from the group consisting of undecene (-undecene).

According to exemplary embodiments, the inorganic alkali-based compound may include lithium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, francium hydroxide, and the like. These may be used alone or in combination of two or more.

In some embodiments, the organic or inorganic alkali-based compound may be included in an amount of about 1 to 15% by weight based on the total weight of the etchant composition. When the content of the organic or inorganic alkali compound is less than about 1% by weight, the degree of dissociation of hydroxide ions or the amount of dissociation from the composition may not be sufficiently secured, and thus the etching rate for the silicon layer may be reduced. When the content of the organic or inorganic alkali-based compound exceeds about 15% by weight, the etching performance of the etchant composition may decrease due to an increase in the amount of surface adsorption by the additive material.

Preferably, the content of the organic or inorganic alkali-based compound may be 5 to 10% by weight based on the total weight of the etchant composition.

The phosphite-based compound may serve as an anticorrosive agent for inhibiting etching of a protective layer (eg, a silicon oxide layer). For example, since the phosphite-based compound may form a direct bond with the surface of the silicon oxide layer through a nucleophilic reaction with the silicon oxide, it may have a passivation effect on the silicon oxide layer. Accordingly, etching damage to the silicon oxide layer by the etching agent can be suppressed, and a high etch selectivity with respect to the silicon layer can be obtained.

According to an exemplary embodiment, the phosphite-based compound may include at least one selected from the group consisting of compounds represented by Chemical Formulas 1 to 4 below.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

In Formulas 1 and 3, R ₁ , R ₂ , R ₃ , R ₇ and R ₈ are each independently an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, a phenyl group, a biphenyl group, a carbon number 7 to It may be one selected from an alkylphenyl group having 16 and a silyl group having 1 to 10 carbon atoms.

In Formulas 2 and 4, R ₄ ⁺ , R ₅ ⁺ , R ₆ ⁺ , R ₉ ⁺ , and R ₁₀ ⁺ may each independently be one of a cation element or an ammonium cation. In some embodiments, the cationic element may be a monovalent cationic element, for example, may be an alkali metal ion such as Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ .

For example, the phosphite-based compound may include dimethyl phosphite, diethyl phosphite, diisopropyl phosphite, dibutyl phosphite, and diphenyl phosphite. (Diphenyl phosphite), disodium hydrogen phosphite, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triisopropyl phosphite phosphite), triphenyl phosphite, tris (2-ethylhexyl) phosphite (Tris (2-ethylhexyl) phosphite), tris (nonylphenyl) phosphite (Tris (nonylphenyl) phosphite), tris (trimethylsilyl) ) Phosphite (Tris (trimethylsilyl) phosphite), dimethyl trimethylsilyl phosphite, tris (1,1,1,3,3,3,-hexafluoro-2-propyl) phosphite (Tris) (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite), tris (2,2,2-trifluoroethyl) phosphite (Tris (2,2,2-trifluoroethyl) phosphite) , Tris (2,4-di-tert-butyl ethyl) phosphite (Tris (2,4-di-tert-butylphenyl) phosphite), triisodecyl phosphite (Triisodecyl phosphite), trisodium phosphite (Trisodium phosphite) , ammonium phosphite and the like. These may be used alone or in combination of two or more.

In a preferred embodiment, the phosphite-based compound may include only the compound represented by Formula 1 and/or Formula 2 above.

In some embodiments, the phosphite-based compound may be included in an amount of about 0.1 to 5% by weight based on the total weight of the etchant composition. When the content of the phosphite-based compound is less than about 0.1% by weight, the anticorrosive effect on the silicon oxide film may be reduced, and when the content of the phosphite-based compound exceeds about 5% by weight, the phosphite-based compound is a silicon film It may act as an etch inhibitor to reduce the etch performance of the etchant composition. Preferably, the phosphite-based compound may be included in an amount of 1 to 5% by weight based on the total weight of the composition.

In exemplary embodiments, the etchant composition may further include a phosphate-based compound or a phosphonate-based compound. In this case, since the phosphate or phosphonate-based compound forms a passivation layer through charge interaction on the surface of the silicon oxide layer, etching of the silicon oxide layer can be suppressed. Accordingly, it is possible to improve the etch selectivity of silicon compared to the silicon oxide layer.

For example, the phosphate-based compound is trimethyl phosphate (Trimethyl phosphate), triethyl phosphate (Triethyl phosphate), tripropyl phosphate (Tripropyl phosphate), triisopropyl phosphate (Triisopropyl phosphate), tributyl phosphate (Tributyl phosphate), tributyl phosphate (Tributyl phosphate) Triphenyl phosphate, diethyl phosphate, diisopropyl phosphate, dibutyl phosphate, diphenyl phosphate, dibenzyl phosphate, dihexa Decyl phosphate (Dihexadecyl phosphate), 2-ethylhexyl phosphate (2-Ethylhexyl phosphate), ammonium phosphate (Ammonium phosphate), triethylammonium phosphate (Triethylammonium phosphate), tetrabutyl ammonium phosphate (Tetrabutylammonium phosphate) and the like may be included. These may be used alone or in combination of two or more.

In some embodiments, the phosphate-based compound may be included in an amount of about 0.1 to 5% by weight based on the total weight of the etchant composition. Within the above range, the corrosion protection effect on the silicon oxide film and the etching selectivity on the silicon film may be excellent.

For example, the phosphonate-based compound may be dimethyl methylphosphonate, diethyl methylphosphonate, dipropyl methylphosphonate, or dibutyl methylphosphonate. methylphosphonate), dimethyl ethylphosphonate, diethyl ethylphosphonate, dipropyl ethylphosphonate, dibutyl ethylphosphonate, dimethyl propylphosphonate , diethyl propylphosphonate, dipropyl propylphosphonate, dibutyl propylphosphonate, and the like. These may be used alone or in combination of two or more.

In some embodiments, the phosphonate-based compound may be included in an amount of about 0.1 to 5% by weight based on the total weight of the etchant composition. Within the above range, the corrosion protection effect on the silicon oxide film and the etching selectivity on the silicon film may be excellent.

The etchant composition may include an extra or residual amount of water. As used herein, the term “extra” or “residual amount” may refer to a variable amount that changes according to the addition of an ingredient or agent. For example, the remaining amount excluding the above-described organic or inorganic alkali compound and phosphite compound, or the remainder excluding organic or inorganic alkali compound, phosphite compound, phosphate compound, phosphonate compound and other additives It can mean quantity.

In some embodiments, the water may be deionized water for a semiconductor process, preferably deionized water having a specific resistance value of 18 MΩ/cm or more.

The additive of the etchant composition may be included within a range that does not impair the etch performance and etch control performance of the organic or inorganic alkali compound and the phosphite compound, for example, an etch enhancer, a corrosion inhibitor, a surfactant, an antifoaming agent, etc. may include

In some embodiments, the etchant composition may not include a fluorine-containing compound. In this case, it is possible to suppress the etching damage of the silicon oxide film by the fluorine-containing compound. Accordingly, it is possible to selectively etch the silicon layer while preventing the silicon oxide layer from being etched.

The silicon etching method using the etching solution composition may be performed by a method commonly known in the art. For example, deposition, spraying, or a method using deposition and spraying may be used in a batch type etching apparatus or a single type etching apparatus. However, these conditions are not strictly applied and may be easily or suitable conditions selected by those skilled in the art.

<Pattern Forming Method>

1 to 5 are schematic cross-sectional views for explaining a pattern forming method according to example embodiments. For example, FIGS. 1 to 5 illustrate a poly-replacement gate or gate-last process in a semiconductor logic device using a silicon film.

However, the etchant composition according to the exemplary embodiments is not limited to the processes of FIGS. 1 to 5 , and may be used in various structures such as wirings, contacts, and gates, or pattern formation processes.

Referring to FIG. 1 , a gate insulating layer 110 and a dummy gate layer 120 may be sequentially formed on a substrate 100 .

The substrate 100 may include a semiconductor material such as single crystal silicon, single crystal germanium, or a group III-V compound.

The gate insulating layer 110 may include silicon oxide, high-k metal oxide, or the like. The dummy gate layer 120 may be formed to include polysilicon or amorphous silicon. For example, the gate insulating layer 110 may be formed through a chemical vapor deposition (CVD) process, a sputtering process, a physical vapor deposition (PVD) process, an atomic layer deposition (ALD) process, or the like.

Referring to FIG. 2 , the dummy gate layer 120 and the gate insulating layer 110 may be partially etched to form a dummy gate 125 and a gate insulating pattern 115 .

For example, a hard mask or a photoresist pattern may be formed on the dummy gate layer 120 . The dummy gate 125 and the gate insulating pattern 115 may be formed through a dry etching process using the hard mask or the photoresist pattern as an etching mask.

Referring to FIG. 3 , the oxide layer 130 may be formed on the substrate 100 to expose the top surface of the dummy gate 125 .

In some embodiments, the oxide layer 130 may be formed to include a silicon oxide layer. For example, after depositing silicon oxide on the substrate, the oxide layer 130 may be formed by planarizing through a chemical mechanical polishing (CMP) process until the top surface of the dummy gate 125 is exposed.

Referring to FIG. 4 , the dummy gate 125 may be removed using the etchant composition according to the above-described exemplary embodiments. An opening 135 may be formed in a space in which the dummy gate 125 is removed.

As described above, the etchant composition has improved corrosion resistance to the silicon oxide layer through the nucleophilic reaction of the phosphite-based compound and silicon oxide, and thus only silicon can be selectively removed from the silicon oxide layer. Accordingly, the nano-scale dummy gate 125 may be uniformly removed without etching defects.

In some embodiments, the etchant composition may be an etchant composition further comprising a phosphate-based compound or a phosphonate-based compound. In this case, the anticorrosive effect on the oxide layer 130 may be improved through the interaction of the phosphate-based compound or the phosphonate-based compound with silicon oxide, and a high etching selectivity for the dummy gate 125 may be secured. .

Referring to FIG. 5 , a gate structure may be formed in the opening 135 .

For example, a barrier film including a metal nitride such as titanium nitride or tantalum nitride, and a gate metal film including a metal such as tungsten, cobalt, or copper may be formed on the oxide film 130 to fill the opening 135 . have. Thereafter, the gate metal layer and the barrier layer may be planarized through a CMP process until the top surfaces of the oxide layer 130 are exposed to form a gate structure including the barrier pattern 140 and the metal gate 150 .

In an embodiment, referring back to FIG. 4 , after the dummy gate 125 is removed, the gate insulating pattern 115 may also be removed. In this case, the gate insulating pattern 115 may serve as a dummy gate insulating layer. Thereafter, before forming the gate structure in the opening 135 , a gate insulating layer may be formed again.

Hereinafter, experimental examples including specific examples and comparative examples are presented to aid understanding of the present invention, but these are merely illustrative of the present invention and do not limit the appended claims, the scope and spirit of the present invention It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope, and it is natural that such variations and modifications fall within the scope of the appended claims.

Examples and Comparative Examples

The components described in Table 1 (Example) and Table 2 (Comparative Example) below were mixed in the corresponding content (wt%), and the etchant composition of Examples and Comparative Examples was prepared by including the remaining amount of water in common.

division
(weight%) alkali compound phosphite phosphate phosphonate water Example 1 5
(A-1) One
(B-1) 94 Example 2 10
(A-1) One
(B-1) 89 Example 3 15
(A-1) One
(B-1) 84 Example 4 One
(A-2) One
(B-1) 98 Example 5 5
(A-3) One
(B-1) 94 Example 6 10
(A-1) 0.1
(B-2) 89.9 Example 7 10
(A-1) 3
(B-3) 87 Example 8 10
(A-1) 5
(B-4) 85 Example 9 10
(A-1) 7
(B-1) 83 Example 10 17
(A-1) One
(B-1) 82 Example 11 0.5
(A-1) One
(B-1) 98.5 Example 12 10
(A-1) 0.05
(B-1) 89.95 Example 13 10
(A-1) One
(B-5) 89 Example 14 10
(A-1) One
(B-1) One
(C-1) 88 Example 15 10
(A-1) One
(B-1) One
(C-2) 88 Example 16 10
(A-1) One
(B-1) One
(C-1) One
(C-2) 87

division
(weight%) alkali compound phosphite phosphate phosphonate phosphine water Comparative Example 1 10
(A-1) One
(C-1) 89 Comparative Example 2 10
(A-1) One
(C-2) 89 Comparative Example 3 10
(A-1) One
(C-3) 89 Comparative Example 4 10
(A-1) One
(C-1) One
(C-2) 88 Comparative Example 5 10
(A-1) 90 Comparative Example 6 One
(B-1) 99

Specific ingredient names listed in Tables 1 and 2 are as follows.

alkali compound

1) A-1: tetramethylammonium hydroxide

2) A-2: Sodium hydroxide

3) A-3: 1,8-diazabicyclo[5.4.0]undec-7-ene (1,8-Diazabicyclo[5.4.0]undec-7-ene)

Phosphite-based compounds

1) B-1: Triethyl phosphite,

2) B-2: Triphenyl phosphite,

3) B-3: Tris (2,2,2-trifluoroethyl) phosphite (Tris (2,2,2-trifluoroethyl) phosphite)

4) B-4: Ammonium phosphite

5) B-5: Diethyl phosphite

other additives

1) C-1: Triethyl phosphate

2) C-2: Diethyl (1-cyanoethyl) phosphonate

3) C-3: Tri (o-tolyl) phosphine (Tri (o-tolyl) phosphine)

Experimental example

(1) Silicon film etch rate evaluation

A specimen was prepared by cutting a silicon wafer into a size of 1.5 X 1.5 cm ² . The specimen was immersed in a thermostat containing the etchant compositions of Examples and Comparative Examples at 80° C. and 400 rpm for 30 seconds. Then, the specimen was taken out, washed with water, and dried using air. After measuring the thickness of the silicon film after etching using an ellipsometer, the etch rate was calculated as a change value compared to the initial film thickness. The evaluation criteria are as follows.

<Evaluation criteria>

◎: Etching rate 3500 Å/min or more

○: Etching rate less than 3000 to 3500 Å/min

△: etch rate less than 2500 to 3000 Å/min

×: Etching rate less than 2500 Å/min

(2) Evaluation of corrosion resistance of silicon oxide film

A specimen was prepared by cutting the silicon oxide film to a size of 1.5 X 1.5 cm ² . The specimens were immersed in the etchant compositions of Examples and Comparative Examples at 80° C. and 400 rpm for 30 seconds. Then, the specimen was taken out, washed with water, and then dried using air. The thickness of the silicon oxide film after etching was measured using an ellipsometer, and the etch rate was calculated as a change value compared to the initial film thickness. Next, the reduction rate of the etch rate was calculated using the following formula. The evaluation criteria are as follows.

<Calculation formula>

<Evaluation criteria>

◎: more than 25% reduction rate

○: reduction rate greater than 15% to 25% or less

△: reduction rate of more than 0% to 15% or less

×: no reduction

The evaluation results are shown together in Table 3 below.

division Silicon film etch rate Silicon oxide film corrosion resistance Example 1 ◎ ◎ Example 2 ◎ ◎ Example 3 ◎ ◎ Example 4 ◎ ◎ Example 5 ◎ ◎ Example 6 ◎ ◎ Example 7 ◎ ◎ Example 8 ◎ ◎ Example 9 △ ◎ Example 10 △ ○ Example 11 △ ◎ Example 12 ◎ △ Example 13 ◎ ○ Example 14 ◎ ◎ Example 15 ◎ ◎ Example 16 ◎ ◎ Comparative Example 1 ◎ Х Comparative Example 2 ◎ Х Comparative Example 3 ◎ Х Comparative Example 4 ◎ Х Comparative Example 5 ◎ Х Comparative Example 6 Х Х

Referring to Tables 1 to 3, in the examples including the alkali-based compound and the phosphite-based compound according to the exemplary embodiments, the etching rate for the silicon film is maintained as compared to the comparative examples as a whole, while the silicon oxide film is Excellent anticorrosive effect was realized.

Comparative Examples 1 to 5 in which the phosphite-based compound was not included had significantly lower selectivity of the silicon film compared to the silicon oxide film.

Comparative Example 6 containing only the phosphite compound did not provide a sufficient etching rate for the silicon layer.

100: substrate 110: gate insulating film
115: gate insulating pattern 120: dummy gate film
125: demi gate 130: oxide film
135: opening 140: barrier pattern
150: metal gate

Claims (12)

organic or inorganic alkali-based compounds;
phosphite-based compounds; and
A silicone etchant composition comprising water.
The silicone etchant composition of claim 1, wherein the organic alkali-based compound comprises one of a quaternary alkyl ammonium salt compound, an azabicyclo compound, a diazabicyclo compound, and a triazabicyclo compound.
The method according to claim 2, wherein the quaternary alkyl ammonium salt compound is ammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, benzyltriethyl hydroxide A silicone etchant composition comprising at least one selected from the group consisting of ammonium, diethyldimethylammonium hydroxide and methyltributylammonium hydroxide.
The silicon etchant composition of claim 1, wherein the inorganic alkali-based compound comprises at least one selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and francium hydroxide.
The method according to claim 1, wherein the phosphite-based compound comprises at least one of the compounds represented by the following Chemical Formulas 1 to 4, Silicone etchant composition:
[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

(In Formulas 1 and 3, R ₁ , R ₂ , R ₃ , R ₇ and R ₈ are each independently an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, a phenyl group, a biphenyl group, a carbon number 7 to an alkylphenyl group having 16 or a silyl group having 1 to 10 carbon atoms,
R ₄ ⁺ , R ₅ ⁺ , R ₆ ⁺ , R ₉ ⁺ and R ₁₀ ⁺ in Formulas 2 and 4 are each independently a cation element or an ammonium cation).
The method according to claim 1, wherein the phosphite-based compound is dimethyl phosphite (Dimethly phosphite), diethyl phosphite (Diethyl phosphite), diisopropyl phosphite (Diisopropyl phosphite), dibutyl phosphite (Dibutyl phosphite), diphenyl Diphenyl phosphite, Disodium hydrogen phosphite, Trimethyl phosphite, Triethyl phosphite, Tributyl phosphite, triisopropyl phosphite (Triisopropyl phosphite), triphenyl phosphite, tris (2-ethylhexyl) phosphite (Tris (2-ethylhexyl) phosphite), tris (nonylphenyl) phosphite (Tris (nonylphenyl) phosphite), tris ( Trimethylsilyl) phosphite (Tris (trimethylsilyl) phosphite), dimethyl trimethylsilyl phosphite, tris (1,1,1,3,3,3,-hexafluoro-2-propyl) phosphite (Tris (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite), tris (2,2,2-trifluoroethyl) phosphite (Tris (2,2,2-trifluoroethyl) phosphite), tris (2,4-di-tert-butyl ethyl) phosphite (Tris (2,4-di-tert-butylphenyl) phosphite), triisodecyl phosphite, trisodium phosphite (Trisodium) phosphite) and ammonium phosphite (Ammonium phosphite) comprising at least one selected from the group consisting of, a silicone etchant composition.
The silicone etchant composition of claim 1, further comprising a phosphate-based compound or a phosphonate-based compound.
The method according to claim 1, wherein in the total weight of the composition,
1 to 15% by weight of the organic or inorganic alkali compound;
0.1 to 5% by weight of the phosphite-based compound; and
A silicone etchant composition comprising the remaining amount of water.
forming a dummy gate by etching the silicon film on the substrate;
forming an oxide layer partially surrounding the dummy gate;
and removing the dummy gate using an etchant composition including an organic or inorganic alkali compound, a phosphite compound, and a residual amount of water.
The method of claim 9 , further comprising forming a gate structure in the opening from which the dummy gate is removed.
The method of claim 10 , wherein the forming of the gate structure comprises forming a barrier pattern and a metal gate sequentially stacked in the opening and including a metal nitride.
The method according to claim 9, wherein the etchant composition further comprises a phosphate-based compound or a phosphonate-based compound.

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