KR20230036677A - Etchant composition for etching silicon and method of forming pattern using the same - Google Patents

Abstract

According to embodiments of the present invention, a silicone etchant composition and a pattern forming method using the same are provided. The silicone etchant composition includes an acidic fluorine-containing compound, an oxidizing agent, a nitrogen-containing compound having a pKa of 8 or more, and water. Accordingly, a silicone etchant composition with improved etching rate and etching selectivity may be provided.

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 etching agent and a solvent and a pattern forming method using the same.

For example, in semiconductor devices such as DRAM, NAND FLASH memory devices, and logic devices, recent critical dimensions (CD) are rapidly decreasing while development to realize large capacity continues.

In the semiconductor device, for example, a silicon-based film or pattern such as polysilicon is widely used as a material for gate electrodes, capacitor electrodes, conductive contacts, wires, and the like. When a gate electrode or wiring is formed through direct etching of a metal film, it is not easy to form a pattern having a desired fine dimension due to limitations in etching resolution, and accordingly, a process using a polysilicon film is being studied.

In order to perform a high-reliability semiconductor device process, a fast etching rate for a removal target and thus excellent etching uniformity are required. 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 film.

Accordingly, it is required to develop an etchant composition for improving etching selectivity while maintaining excellent etching rate and etching uniformity for forming fine dimension patterns during a silicon film etching process.

For example, Korean Patent Publication No. 10-2010-0080780 discloses a silicon etchant composition.

Korean Patent Publication No. 10-2010-0080780

One object of the present invention is to provide a silicone etchant composition having improved etching efficiency and reliability.

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

1. acidic fluorine-containing compounds; oxidizer; an anticorrosive agent comprising a nitrogen-containing compound having a pKa of 8 or higher; and water, a silicone etchant composition.

2. The silicone etchant composition according to 1 above, wherein the nitrogen-containing compound has a pKa of 8 to 30.

3. The silicon etchant composition according to 1 above, wherein the nitrogen-containing compound contains 4 to 11 carbons in its molecular structure.

4. The silicone etchant composition according to 1 above, wherein the nitrogen-containing compound comprises a cyclic amine compound.

5. In the above 1, the molar ratio of the nitrogen-containing compound to the acidic fluorine-containing compound is 0.85 to 1.05, the silicone etchant composition.

6. In the above 1, the acidic fluorine-containing compound is hydrofluoric acid (HF), boric acid (HBF ₄ ), fluorosilicic acid (H ₂ SiF ₆ ), fluorinated antimonic acid (H ₂ FSbF ₆ ) and bifluorinated acid. A silicone etchant composition comprising at least one selected from the group consisting of ammonium (NH ₄ HF ₂ ).

7. The method of 1 above, wherein the oxidizing agent comprises at least one selected from the group consisting of hydrogen peroxide, nitric acid, nitrates, nitrous acid, nitrites, periodic acid, periodates, perchloric acid and perchlorates, Silicone etchant composition.

8. In the above 1, of the total weight of the silicone etchant composition, 0.05 to 2% by weight of the acidic fluorine-containing compound; 0.5 to 20% by weight of the oxidizing agent; and excess water.

9. The silicone etchant composition according to 1 above, wherein the pH of the silicone etchant composition is 5.5 to 8.

10. Forming a silicon-containing film on the substrate; forming an oxide film partially on the silicon-containing film; and etching the silicon-containing film with the silicon etchant composition according to claim 1 .

11. The pattern forming method according to 10 above, wherein the oxide film is used as an etching mask.

12. The method of forming a pattern according to 10 above, wherein the etching of the silicon-containing film comprises forming a gate pattern by etching the silicon-containing film.

The silicone etchant composition according to embodiments of the present invention may include an acidic fluorine-containing compound, an oxidizing agent, and a nitrogen-containing compound having a pKa of 8 or more. The acidic fluorine-containing compound provides fluorine ions to uniformly remove an etch target film at a high speed. Accordingly, etching uniformity may be improved while etching efficiency of the silicon layer is increased. Therefore, it is possible to prevent an increase in surface roughness of the etch target layer due to the etching process, and to provide excellent surface roughness.

The nitrogen-containing compound can stably passivate the surface of a passivation film, for example, a silicon oxide film, and accordingly, an etching selectivity with respect to a silicon film can be improved. In addition, as the nitrogen-containing compound has a pKa of 8 or more, an increase in surface roughness due to over-etching may be prevented, and the reliability of the micropattern shape may be excellent.

In some embodiments, the silicone etchant composition may have a pH in the neutral region, and an excessive increase in etching rate by fluorine ions may be suppressed, thereby improving etching selectivity and etching uniformity.

1 to 7 are schematic cross-sectional views illustrating a pattern forming method according to exemplary embodiments.

Exemplary embodiments of the present invention provide a silicon etchant composition including an acidic fluorine-containing compound, an oxidizing agent, a nitrogen-containing compound-containing anticorrosive agent, and water, and having improved etching efficiency and etching selectivity for silicon. In addition, a method of forming a pattern using the silicone etchant composition is provided.

As used herein, the term "silicon" may refer to monocrystalline silicon, polysilicon and/or amorphous silicon.

Referring to the following experimental examples and drawings, the embodiments of the present invention will be described in more detail. However, the embodiments attached to this specification provide some preferred examples, and serve to further understand the technical idea of the present invention together with the contents of the above-described invention, so the present invention is limited to those described in the embodiments. It should not be construed as limiting.

<Silicone etchant composition>

A silicone etchant composition according to exemplary embodiments (hereinafter, may be abbreviated as an etchant composition) is an acidic fluorine-containing compound, an oxidizing agent containing a nitrogen-containing compound having a pKa (acid dissociation constant) of 8 or more, and water can include

The acidic fluorine-containing compound can etch or strip silicon, and can be used as a main etching agent for an etchant composition. As used herein, the term "acidic compound" may refer to a compound having a pH of less than 7 when present in an aqueous solution under conditions of 1 atm and 25°C.

For example, the acidic fluorine-containing compound may provide fluorine ions as an etching source, and intermolecular or intramolecular bonds in the silicon film may be cleaved by the fluorine ions.

By including the fluorine-containing compound as a main etching agent in the silicone etchant composition, surface roughness of the film to be etched may be reduced. For example, since fluorine ions dissociated from a fluorine-containing compound have an isotropic etching characteristic with respect to an etch target film (eg, a silicon film), etching non-uniformity depending on the surface area of the etch target film can be reduced. there is.

In some embodiments, the acidic fluorine-containing compound may include a fluoric acid compound. For example, hydrofluoric acid such as hydrofluoric acid (HF), fluoroboric acid such as boric acid (HBF ₄ ), fluorosilicic acid (H ₂ SiF ₆ ), fluorinated antimonic acid (H ₂ FSbF ₆ ) and polyfluorinated It may include ammonium (NH ₄ HF ₂ ) and the like, which are acidic in an aqueous solution, and the like. These may be used alone or in combination of two or more. Preferably, hydrofluoric acid may be included in consideration of the concentration of fluorine ions in the etchant composition and the etching selectivity of silicon to silicon oxide.

In some embodiments, the content of the acidic fluorine-containing compound may be 0.05 to 2% by weight, preferably 0.1 to 1% by weight, based on the total weight of the silicone etchant composition. When the content of the acidic fluorine-containing compound is less than 0.05% by weight, fluorine ions may not be sufficiently provided, and thus the etching rate and etching efficiency may decrease. When the content of the acidic fluorine-containing compound exceeds 2% by weight, the concentration of fluorine ions may be excessively high, and the pH of the etchant composition may increase. In this case, an over-etching or undercut phenomenon may occur due to an excessively increased etching rate, and etching or etching of a protective film (eg, an oxide film or a nitride film) may occur.

The oxidizing agent may be used as an auxiliary etching agent or an etching enhancer of a silicone etchant composition. For example, the oxidizing agent may oxidize the surface of the silicon-containing film, and accordingly, the etching rate and etching efficiency by fluorine ions may be further improved.

For example, the surface of the silicon oxide layer may be oxidized by the oxidizing agent to form a Si—OH bond, and fluorine ions may easily cut the silicon bond. Accordingly, the etching property of the acidic fluorine-containing compound to the silicon-containing film can be increased.

In some embodiments, the oxidizing agent may include hydrogen peroxide (H ₂ O ₂ ), nitric acid, nitrate, nitrous acid, nitrite, periodic acid, periodate, perchloric acid or a perchlorate. These may be used alone or in combination of two or more.

Preferably, hydrogen peroxide may be included as an oxidizing agent of the silicone etchant composition. In this case, the pH of the etchant composition can be easily adjusted to a neutral region, and since the initial etching rate for the silicon-containing film can be relatively increased, the etching rate can be easily controlled.

In some embodiments, the content of the oxidizing agent may be 0.5 to 20% by weight, preferably 3 to 10% by weight, based on the total weight of the silicone etchant composition.

When the content of the oxidizing agent is less than 0.5% by weight, an oxidation reaction on the surface of the silicon-containing film may not sufficiently occur, and the etching rate of the silicon-containing film may be reduced. When the content of the oxidizing agent is greater than 20% by weight, the surface of the silicon-containing film is completely oxidized, and the etching selectivity of the silicon-containing film to the silicon oxide film may decrease. For example, when the content of the oxidizing agent is 20% by weight or less, there may be a region in which a Si—OH bond is not formed partially on the surface of the silicon-containing film. In this case, the silicon bonding structure in the surface of the silicon-containing layer may be damaged to form a dangling bond, and the silicon oxide layer may be etched more quickly by fluorine ions than the silicon oxide layer.

The anticorrosive agent may include a nitrogen-containing compound. For example, the nitrogen-containing compound may play a role of inhibiting etching of a passivation layer (eg, a silicon oxide layer). For example, the nitrogen-containing compound can passivate the oxide film through an interaction between charges on the surface of the silicon oxide film, and can prevent etching damage of the silicon oxide film by an etching agent. Accordingly, a high etching selectivity to silicon can be obtained.

The nitrogen-containing compound may have a pKa of 8 or greater. The 　pKa may mean an acid dissociation constant, for example, an acid dissociation constant in an aqueous solution under conditions of 1 atm and 25°C. In this case, the acidity of the etchant composition may be prevented by the nitrogen-containing compound, and the pH of the etchant composition may be adjusted to a neutral region.

For example, in the case of an aqueous composition including an acidic fluorine-containing compound and an oxidizing agent, the composition may have a low pH of 5 or less due to the acidic compound. In this case, the degree of dissociation of fluorine ions in the etchant composition may be excessively high, and some fluorine ions may exist in the form of HF ₂ ^- having strong etching properties. Accordingly, an etching rate of the silicon oxide layer or the silicon nitride layer may be increased, and an etching selectivity may be reduced.

As described above, by including the nitrogen-containing compound having a pKa of 8 or more in the silicon etchant composition, the pH of the etchant composition may be adjusted to a neutral region. Accordingly, the etching selectivity of silicon to silicon oxide may be improved, and the etching rate may be appropriately controlled, resulting in excellent etching uniformity.

For example, the pKa of the nitrogen-containing compound may be 8 to 35, specifically 14 to 25. Within the above range, the composition may have a neutral pH, preventing over-etching of silicon and a decrease in etching rate, and suppressing a difference in etching rate depending on the surface or crystal plane of silicon.

According to example embodiments, the nitrogen-containing compound may include 4 to 11 carbon atoms in a molecular structure. In this case, the anticorrosive effect on silicon oxide can be improved due to the carbon chain of the nitrogen-containing compound. For example, when the number of carbon atoms of the nitrogen-containing compound is less than 4, etching uniformity may be reduced and the surface roughness of the etch target layer may increase. If the nitrogen-containing compound has more than 11 carbon atoms, the solubility of the nitrogen-containing compound in the composition may decrease. For example, in the case of carbazole having 12 carbon atoms, it may not be dissolved in the etchant composition, and etching performance for silicon may be deteriorated.

In some embodiments, the nitrogen-containing compound is an amine-based compound such as a hydroxyl group-containing amine compound (eg, alkanol amine), a linear amine compound, a cyclic amine compound, and/or an alkyl ammonium hydroxide. can include

For example, the amine-based compound may be a primary amine, secondary amine, or tertiary amine, and the alkyl ammonium hydroxide may be a quaternary ammonium hydroxide-based compound.

Examples of the hydroxyl group-containing amine compound include diethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol, 2-amino-1-butanol, 2-amino-3-methyl- 1-butanol, dimethylamino-2-methyl-1-propanol, tris(hydroxymethyl)aminomethane, 2-amino-2-methyl-1,3-propanediol, 2-dimethylaminoethanol, 1-dimethylamino- 2-propanol, 3-dimethylamino-1-propanol, 3-diethylamino-1-propanol, 2-ethylaminoethanol, 2-diethylaminoethanol, 2-dipropylaminoethanol, 2-N-dibutylamino ethanol, N-isopropyldiethanolamine, N-isobutyldiethanolamine, N-n-butyldiethanolamine, N-t-butyldiethanolamine, triisopropanolamine, 2-aminocyclohexanol and the like. These may be used alone or in combination of two or more.

Examples of the cyclic amine compound include 8-azabicyclo[3.2.1]octane, 1,8-azabicyclo[6.3.2]tridecane, 11-azabicyclo[4.4.1]undecane- monoazabicyclo compounds such as 1,3,5,7,9-pentene; 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, 2,8-diazabicyclo[4.3.0]nonane, 1,4-diazabicyclo[4.3.0]nonane, 1,4-diazabicyclo[3.2.2]nonane, 1,4-diazabicyclo[2.2.2]octane, 1,4-diazabicyclo[ diazabicyclo compounds such as 3.2.1]octane and 3-benzyl-3,8-diazabicyclo[3.2.1]octane; Triazabicyclo compounds such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene etc. can be mentioned. These may be used alone or in combination of two or more.

Examples of the alkyl ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ethyltrimethylammonium hydroxide, tris(2-hydroxyethyl ) methyl ammonium hydroxide, benzyl trimethyl ammonium hydroxide and the like. These may be used alone or in combination of two or more.

Preferably, the nitrogen-containing compound may include a cyclic amine compound. In this case, the anticorrosive effect may be further enhanced by the ring-shaped structure, and surface roughness due to etching may be reduced.

In some embodiments, the molar ratio of the nitrogen-containing compound to the acidic fluorine-containing compound may be 0.85 to 1.05, preferably 0.9 to 1.0.

When the molar ratio of the nitrogen-containing compound to the acidic fluorine-containing compound is less than 0.85, the etching rate for silicon oxide increases, and the etching selectivity for silicon may decrease. When the molar ratio of the nitrogen-containing compound to the acidic fluorine-containing compound is greater than 1.05, the etchant composition may have alkalinity. In this case, hydroxide ions (OH ^- ) having anisotropic etching characteristics may be provided as an etching source. can Accordingly, the uniformity of the etching rate according to the etching area may be deteriorated, and the etching profile may be defective.

According to exemplary embodiments, the pH of the silicone etchant composition may be 5.5 to 8, preferably 6 to 7.5, and more preferably 6 to 7. For example, the pH of the etchant composition may be a value measured using a pH meter under conditions of 1 atmospheric pressure and 25°C. An excessive increase in the etch rate within the above range may be prevented, and surface roughness of the etch target layer may be reduced by preventing over-etching and etching non-uniformity. In addition, the etching selectivity of the etch target layer with respect to the protective film (eg, silicon oxide layer) may be excellent.

For example, the etching rate of the silicon etchant composition for the single crystal silicon film may be 60 to 150 Å/min, preferably 80 Å/min or more and less than 120 Å/min. Within the above range, it is possible to effectively control the etching process while maintaining the efficiency of the etching process and the productivity of the product excellently.

The etchant composition may include an excess or residual amount of water. As used in this application, the terms "surplus" or "remaining amount" can refer to a variable amount that changes with the addition of ingredients or agents. For example, the remaining amount of the acidic fluorine-containing compound, the oxidizing agent, and the anticorrosive agent containing the nitrogen-containing compound, or the acidic fluorine-containing compound, the oxidizing agent, the anticorrosive agent containing the nitrogen-containing compound, and/or other additives. It may mean the remaining amount except for .

In some embodiments, the water may be deionized water for semiconductor processing, and preferably, deionized water having a resistivity value of 18 MΩ/cm or more may be used.

The silicone etchant composition may include other additives within a range that does not impair etching performance and etching control performance of an acidic fluorine-containing compound, an oxidizing agent, and an anticorrosive agent including a nitrogen-containing compound having a pKa of 8 or more. For example, the additives may include an etching accelerator, a corrosion inhibitor, a surfactant, and an antifoaming agent.

A silicon etching method using the etchant composition may be performed by a method commonly known in the art. For example, a method using immersion, spraying, or immersion and spraying may be used in a batch type etching device or a single type etching device. However, these conditions are not strictly applied, and can be easily or appropriately selected by those skilled in the art.

<Pattern formation method>

1 to 7 are schematic cross-sectional views for explaining a pattern forming method according to exemplary embodiments.

However, the etchant composition according to exemplary embodiments is not limitedly used in the process of FIGS. 1 to 7, and forms various structures or patterns such as wires, contacts, gates, etc., as long as they are included in the spirit and technical scope of the present invention. can be used in the process.

1 to 3 are schematic cross-sectional views illustrating a method of manufacturing a semiconductor device according to example embodiments.

Referring to FIG. 1 , an insulating film 110 may be formed on the substrate 100 , and a silicon-containing film 120 may be formed on the insulating film 110 .

The substrate 100 may include a semiconductor material such as single crystal silicon or single crystal germanium, and may include polysilicon.

The insulating layer 110 may be formed to include an insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or polysiloxane. For example, the 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.

The silicon-containing layer 120 may include monocrystalline silicon, polysilicon, or amorphous silicon.

Referring to FIG. 2 , an oxide film 130 may be formed on the silicon-containing film 120 . The oxide layer 130 may be formed to include a silicon oxide layer. For example, the oxide layer 130 may be formed through a CVD process, a sputtering process, a PVD process, an ALD process, or the like.

A mask pattern 132 may be formed by partially etching the oxide layer 130 . For example, a portion of the oxide layer 130 may be partially etched until a portion of the upper surface of the silicon-containing layer 120 is exposed.

Referring to FIG. 3 , the silicon-containing layer 120 may be partially removed using the etchant composition according to the exemplary embodiments described above. Accordingly, the gate pattern 122 may be formed from the silicon-containing layer 120 .

As described above, since the etchant composition includes an acidic fluorine-containing compound, an oxidizing agent, and a nitrogen-containing compound having a pKa of 8 or more, etching efficiency for silicon and anticorrosion effect for silicon oxide can be improved. Accordingly, the highly reliable gate pattern 122 may be formed by selectively etching only the silicon-containing layer 220 while effectively preventing etching of the mask pattern 132 .

4 to 7 are schematic cross-sectional views for explaining a pattern forming method according to exemplary embodiments.

Referring to FIG. 4 , an oxide film 210 may be formed on the substrate 200 .

The substrate 200 may be a silicon substrate including monocrystalline silicon, polysilicon, or amorphous silicon.

The oxide layer 210 may include a silicon oxide layer. In this case, silicon oxide 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, etc. to cover the upper surface of the substrate 200. there is.

Referring to FIG. 5 , a mask pattern 215 may be formed by partially etching the oxide film 210 . For example, a portion of the oxide film 210 may be etched until a portion of the upper surface of the substrate 200 is exposed.

Referring to FIG. 6 , the upper portion of the substrate 200 may be partially etched using the etchant composition according to the exemplary embodiments described above. Accordingly, the trench 220 may be formed inside the substrate 200 .

As described above, etching of the mask pattern 215 may be prevented using the etchant composition, and only the upper portion of the substrate 200 may be selectively etched. Therefore, for example, in the nano-scale fine etching process, the upper portion of the substrate 200 can be removed without etching defects, and a highly reliable etching process can be performed.

Referring to FIG. 7 , an insulating pattern 230 may be formed inside the trench 220 .

The insulating pattern 230 may be formed to include an insulating material including silicon oxide, silicon nitride, silicon oxynitride, or polysiloxane. For example, the insulating material may be formed through a CVD process, a sputtering process, a PVD process, an ALD process, etc. to fill the inside of the trench 220 .

Hereinafter, experimental examples including specific examples and comparative examples are presented to aid understanding of the present invention, but these are only illustrative of the present invention and do not limit the scope of the appended claims, and the scope and technical 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 these changes and modifications fall within the scope of the appended claims.

Examples and Comparative Examples

Etch compositions according to Examples and Comparative Examples were prepared with the compositions and contents (wt%) shown in Tables 1 and 2 below.

The pH of the etchant composition was measured using a pH meter (Seven multi AG 8603, manufactured by Mettler Toledo) after stirring the etchant composition at 120 rpm for 1 hour under conditions of 1 atm and 25 ° C.

Fluorine-Containing Compound (A) Oxidizer (B) Anticorrosive (C) deionized water
(content) pH division content division content division content Example 1 A-1 0.05 B-1 3.1 C-1 0.38 96.47 6.8 Example 2 A-1 0.1 B-1 3.1 C-1 0.76 96.04 6.7 Example 3 A-1 0.15 B-1 3.1 C-1 1.14 95.61 6.5 Example 4 A-1 0.5 B-1 3.1 C-1 3.80 92.6 6.4 Example 5 A-1 1.0 B-1 3.1 C-1 7.61 88.29 6.4 Example 6 A-1 2.0 B-1 3.1 C-1 15.22 79.68 6.2 Example 7 A-1 0.15 B-1 0.1 C-1 1.14 98.61 6.8 Example 8 A-1 0.15 B-1 0.5 C-1 1.14 98.21 6.7 Example 9 A-1 0.15 B-1 6.2 C-1 1.14 92.51 6.2 Example 10 A-1 0.15 B-1 9.3 C-1 1.14 89.41 6.4 Example 11 A-1 0.15 B-1 18.6 C-1 1.14 80.11 6.7 Example 12 A-1 0.15 B-1 3.1 C-1 0.97 95.78 6.1 Example 13 A-1 0.15 B-1 3.1 C-1 1.20 95.55 7.8 Example 14 A-1 0.15 B-1 3.1 C-2 0.93 95.82 6.8 Example 15 A-1 0.15 B-1 3.1 C-3 0.84 95.91 6.9 Example 16 A-1 0.15 B-1 3.1 C-4 0.83 95.92 6.7 Example 17 A-1 0.15 B-1 3.1 C-5 1.04 95.71 6.9 Example 18 A-1 0.15 B-1 3.1 C-6 0.89 95.86 7.0 Example 19 A-1 0.15 B-1 3.1 C-7 0.86 95.89 6.6 Example 20 A-1 0.15 B-1 3.1 C-8 0.86 95.89 7.1 Example 21 A-1 0.15 B-1 3.1 C-9 1.95 94.8 6.5 Example 22 A-1 0.15 B-1 3.1 C-10 0.45 96.3 6.6 Example 23 A-1 0.03 B-1 3.1 C-1 0.23 96.64 7.0 Example 24 A-1 2.5 B-1 3.1 C-1 19.02 75.38 6.1 Example 25 A-1 0.15 B-1 21.9 C-1 1.14 76.81 6.3 Example 26 A-1 0.15 B-1 3.1 C-1 0.57 96.18 5.2 Example 27 A-1 0.15 B-1 3.1 C-1 1.37 95.38 8.6 Example 28 A-1 0.15 B-2 3.1 C-1 7.76 88.99 6.3 Example 29 A-1 0.15 B-2 3.1 C-9 13.22 83.33 6.2 Example 30 A-2 0.43 B-1 3.1 C-1 1.14 95.33 6.2 Example 31 A-2 0.43 B-2 3.1 C-1 13.22 83.25 6.1

Fluorine-Containing Compound (A) Oxidizer (B) Anticorrosive (C) deionized water
(content) pH division content division content division content Comparative Example 1 - - B-1 3.1 C-1 1.14 95.76 12.8 Comparative Example 2 A-1 0.15 - - C-1 1.14 98.71 6.8 Comparative Example 3 A-1 0.1 B-1 3.1 - - 96.8 3.1 Comparative Example 4 A-1 0.15 B-1 3.1 C-11 1.14 95.61 6.1 Comparative Example 5 A-1 0.15 B-1 3.1 C-12 0.51 96.24 5.6 Comparative Example 6 A-1 1.0 B-1 3.1 C-13 0.41 95.49 6.8 Comparative Example 7 A-2 0.43 B-1 3.1 C-11 1.14 95.33 5.7 Comparative Example 8 A-2 0.43 B-1 3.1 C-12 0.51 95.96 5.1 Comparative Example 9 A-3 0.28 B-1 3.1 C-1 1.14 95.43 8.3 Comparative Example 10 A-3 0.28 B-1 3.1 C-9 1.95 94.67 7.8 Comparative Example 11 A-3 0.28 B-2 3.1 C-1 1.14 95.43 1.7

The specific component names listed in Tables 1 and 2 are as follows.

Fluorine-containing compounds (A)

A-1: Hydrogen fluoride (HF) (Mw: 20)

A-2: Ammonium bifluoride (NH ₄ HF ₂ ) (Mw: 57)

A-3: Ammonium fluoride (NH ₄ F) (Mw: 37)

Oxidizer (B)

B-1: hydrogen peroxide

B-2: nitric acid

Anticorrosive (C)

C-1: 1,8-diazabicyclo [5.4.0] undec-7-ene (pKa: 13.5, Mw: 152)

C-2: 1,5-diazabicyclo [4.3.0] non-5-ene (pKa: 12.7, Mw: 124)

C-3: 1,4-diazabicyclo [2.2.2] octane (1,4-diazabicyclo [2,2,2] octane) (pKa: 8.7, Mw: 112)

C-4: 8-azabicyclo[3.2.1]octane (pKa: 10.3, Mw: 111)

C-5: 1,5,7-triazabicyclo [4.4.0] dec-5-ene (pKa: 25.2, Mw: 139 )

C-6: N-methyldiethanolamine (pKa: 8.6, Mw: 119)

C-7: 2-aminocyclohexanol (pKa: 14.9, Mw: 115)

C-8: 1,2-diaminocyclohexane (pKa: 9.9, Mw: 114)

C-9: tetrabutylammonium hydroxide (pKa: 14.0, Mw: 259)

C-10: 1,2-diaminoethane (pKa: 9.7, Mw: 60)

C-11: triethanolamine (pKa: 7.74, Mw: 149)

C-12: imidazole (pKa: 6.8, Mw: 68)

C-13: Potassium hydroxide (pKa: 14.7, Mw: 56)

Experimental example

(1) Evaluation of silicon film etching rate

A monocrystalline silicon wafer was cut into a size of 1.5 X 1.5 cm ² . The cut silicon wafer was immersed in a solution diluted with hydrofluoric acid and ultrapure water at a weight ratio of 200:1 for 1 minute to prepare a specimen from which oxides and foreign substances formed on the surface were removed. Thereafter, the thickness of the specimen was measured using an ellipsometer.

The etchant compositions of Examples and Comparative Examples were put into a thermostat and stirred at a rotational speed of 400 rpm using a magnetic bar at a temperature of 60 °C. Thereafter, the prepared specimen was immersed in a thermostat containing an etchant composition for 1 minute at 60 °C. Subsequently, the specimen was washed with ultrapure water for 30 seconds and then dried using air. Thereafter, the thickness of the specimen was measured using an ellipsometer, and the etching rate was calculated as a change value compared to the initial thickness. The evaluation criteria are as follows.

<Evaluation Criteria>

◎: 80 Å/min or more and less than 120 Å/min

○: 60 Å/min or more and less than 80 Å/min, or 120 Å/min or more and less than 150 Å/min

△: 40 Å/min or more and less than 60 Å/min, or 150 Å/min or more and less than 210 Å/min

×: Less than 40 Å/min or 210 Å/min or more

(2) Evaluation of silicon oxide film etch rate

A silicon oxide wafer was cut to a size of 1.5 X 1.5 cm ² . The cut silicon oxide wafer was immersed in a solution diluted with hydrofluoric acid and ultrapure water at a weight ratio of 200:1 for 10 seconds to prepare a specimen from which surface foreign matter was removed. After that, the thickness of the specimen was measured using an ellipsometer.

The etchant compositions of Examples and Comparative Examples were put into a thermostat and stirred at a rotational speed of 400 rpm using a magnetic bar at a temperature of 60 °C. Thereafter, the prepared specimen was immersed in a thermostat containing an etchant composition at 60° C. for 10 minutes. Subsequently, the specimen was washed with ultrapure water for 30 seconds and then dried using air. Thereafter, the thickness of the specimen was measured using an ellipsometer, and the etching rate was calculated as a change value compared to the initial thickness. The evaluation criteria are as follows.

<Evaluation Criteria>

◎: Etch rate of 5 Å/min or less

○: Etch rate greater than 5 Å/min to 10 Å/min or less

△: Etch rate greater than 10 Å/min to 25 Å/min or less

×: Etch rate exceeding 25 Å/min

(3) Evaluation of surface roughness

Surface roughness (Rq) of the surface of the silicon film etched in Experimental Example (1) was measured using an atomic force microscope (AFM). The evaluation criteria are as follows.

<Evaluation Criteria>

◎: 0.1 nm or less

○: more than 0.1 nm and 0.5 nm or less

△: more than 0.5 nm and less than or equal to 1.5 nm

×: greater than 1.5 nm

Silicon film etch evaluation Silicon oxide etch evaluation surface roughness 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 ◎ ◎ ◎ Example 17 ◎ ◎ ◎ Example 18 ◎ ◎ ◎ Example 19 ◎ ◎ ◎ Example 20 ◎ ◎ ◎ Example 21 ◎ ◎ ◎ Example 22 ○ ○ △ Example 23 △ ◎ ◎ Example 24 △ △ △ Example 25 △ ◎ △ Example 26 △ △ ○ Example 27 △ ◎ △ Example 28 ◎ △ ○ Example 29 ◎ △ △ Example 30 ◎ ○ ◎ Example 31 ◎ △ △

Silicon film etch evaluation Silicon oxide etch evaluation surface roughness Comparative Example 1 X ○ X Comparative Example 2 X ◎ ◎ Comparative Example 3 X X ◎ Comparative Example 4 △ X ○ Comparative Example 5 △ X △ Comparative Example 6 △ △ X Comparative Example 7 ○ X △ Comparative Example 8 △ X X Comparative Example 9 X ○ △ Comparative Example 10 X ○ X Comparative Example 11 X X X

Referring to Tables 3 and 4, the compositions according to the examples include an acidic fluorine-containing compound, an oxidizing agent, a nitrogen-containing compound having a pKa of 8 or more, and water in predetermined amounts, and have improved etching rate, selectivity, and It can be confirmed that etching uniformity is provided.

It can be seen that the compositions of Examples 24 and 25 have relatively high contents of the nitrogen-containing compound or the oxidizing agent, respectively, so that the etching performance of the silicon-containing film is slightly deteriorated. It can be seen that the composition of Example 26 has a low pH, and therefore, the anticorrosive performance of the silicon oxide film is slightly deteriorated. Since the composition of Example 27 has a relatively high pH, it can be confirmed that the etching performance of the silicon-containing film is slightly deteriorated.

Referring to the Comparative Examples, it can be seen that the composition of Comparative Example 1 lacking an acidic fluorine-containing compound has poor etching characteristics for the silicon film and increased surface roughness due to the strong base.

It can be seen that the compositions of Comparative Examples 2 and 3 lacking an oxidizing agent or an anticorrosive agent significantly lowered the etching rate of the silicon film. It can be seen that the compositions of Comparative Examples 4, 5, 7, and 8 including the nitrogen-containing compound having a pKa of less than 8 exhibit deterioration in anticorrosive performance against the silicon oxide film.

In the case of Comparative Example 6 lacking a nitrogen-containing compound, etching uniformity was reduced, and accordingly, it can be seen that the surface roughness of the film to be etched is high. It can be seen that the compositions of Comparative Examples 9 to 12 containing alkaline fluoride as the fluorine-containing compound did not provide etching performance for the silicon film, and the etching rate was very slow, increasing the surface roughness of the silicon film.

100, 200: substrate 110: insulating film
120: silicon-containing film 122: gate pattern
130, 210: oxide film 132, 215: mask pattern
220: trench 230: insulation pattern

Claims (12)

acidic fluorine-containing compounds;
oxidizer;
an anticorrosive agent comprising a nitrogen-containing compound having a pKa of 8 or higher; and
A silicone etchant composition comprising water.
The method according to claim 1, pKa of the nitrogen-containing compound is 8 to 30, the silicone etchant composition.
The silicone etchant composition of claim 1, wherein the nitrogen-containing compound contains 4 to 11 carbons in its molecular structure.
The silicone etchant composition of claim 1, wherein the nitrogen-containing compound includes a cyclic amine-based compound.
The method according to claim 1, wherein the molar ratio of the nitrogen-containing compound to the acidic fluorine-containing compound is 0.85 to 1.05, the silicone etchant composition.
The method according to claim 1, wherein the acidic fluorine-containing compound is hydrofluoric acid (HF), boric acid (HBF ₄ ), fluorosilicic acid (H ₂ SiF ₆ ), fluorinated antimonic acid (H ₂ FSbF ₆ ) and ammonium bifluoride ( NH ₄ HF ₂ ), a silicone etchant composition comprising at least one of.
The method according to claim 1, wherein the oxidizing agent comprises at least one selected from the group consisting of hydrogen peroxide, nitric acid, nitrates, nitrous acid, nitrites, periodic acid, periodates, perchloric acid and perchlorates, silicone etchant composition.
The method according to claim 1, of the total weight of the silicone etchant composition,
0.05 to 2% by weight of the acidic fluorine-containing compound;
0.5 to 20% by weight of the oxidizing agent; and
A silicone etchant composition comprising excess water.
The method according to claim 1, wherein the pH of the silicone etchant composition is 5.5 to 8, the silicone etchant composition.
forming a silicon-containing film on the substrate;
forming an oxide film partially on the silicon-containing film; and
A pattern forming method comprising the step of etching the silicon-containing film with the silicon etchant composition according to claim 1.
The method of claim 10 , wherein the oxide film is used as an etching mask.
The method of claim 10 , wherein the etching of the silicon-containing layer comprises forming a gate pattern by etching the silicon-containing layer.

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