KR102576574B1 - Etching composition, method for etching insulating layer of semiconductor devices using the same and method for preparing semiconductor devices - Google Patents

Abstract

The present invention seeks to provide an etching composition, which includes phosphoric acid and a silane compound represented by the following formula (1).
[Formula 1]

In Formula 1, R ₁ to R ₇ are each independently hydrogen ^, hydrocarbyl, or non-hydrocarbyl, and It is an anion, an anion derived from nitric acid, an anion derived from carbonic acid, or an anion derived from carboxylic acid, L _p is hydrocarbylene, p is 0 or 1, A is an n-valent radical, and n is an integer of 1 to 4.

Description

Etching composition, method of etching an insulating film using the same, and method of manufacturing a semiconductor device {ETCHING COMPOSITION, METHOD FOR ETCHING INSULATING LAYER OF SEMICONDUCTOR DEVICES USING THE SAME AND METHOD FOR PREPARING SEMICONDUCTOR DEVICES}

The present invention relates to an etching composition, particularly an etching composition with high selectivity that can selectively remove a nitride film while minimizing the etching rate of the oxide film.

Oxide films such as silicon oxide (SiO ₂ ) and nitride films such as silicon nitride (SiNx) are representative insulating films, and in the semiconductor manufacturing process, these silicon oxide films or silicon nitride films are used alone or with one or more layers alternately stacked. Additionally, these oxide and nitride films are also used as hard masks to form conductive patterns such as metal wiring.

In a wet etching process to remove a nitride film, a mixture of phosphoric acid and deionized water is generally used. Deionized water is added to prevent a decrease in the etching rate and a change in etching selectivity for the oxide film, but there is a problem in that even a slight change in the amount of deionized water supplied causes defects in the nitride film etching removal process. Additionally, phosphoric acid is a strong acid and is corrosive, making handling difficult.

To solve this problem, a method of removing the nitride film using an etching composition containing phosphoric acid (H ₃ PO ₄ ) and hydrofluoric acid (HF) or nitric acid (HNO ₃ ) was known in the prior art, but rather, the method of etching the nitride film and the oxide film was known. This resulted in inhibiting rain. In addition, there is a known technology using phosphoric acid and silicate, or an etching composition containing silicic acid, but silicic acid or silicate causes particles that can affect the substrate, which has the problem of being unsuitable for the semiconductor manufacturing process.

However, when phosphoric acid is used in the wet etching process to remove the nitride film, not only the nitride film but also the SOD oxide film is etched due to a decrease in the etching selectivity between the nitride film and the oxide film, making it difficult to control the effective field oxide height (EFH). Lose. Accordingly, sufficient wet etching time for removal of the nitride film cannot be secured or additional processes are required, causing changes and adversely affecting device characteristics.

Therefore, in the semiconductor manufacturing process, there is a need for an etching composition with a high selectivity that selectively etches the nitride film with respect to the oxide film and does not cause problems such as particle generation.

Meanwhile, silane-based additives, which are additives added to conventional etching compositions, have low solubility, so appropriate solubility is not secured, which causes precipitation of particles in the etching composition and abnormal growth of the substrate. These particles remain on the silicon substrate, causing defects in devices implemented on the substrate, or remain in equipment used in etching or cleaning processes, causing equipment failure.

Furthermore, when the etchant is stored for a long period of time, the etching speed of the nitride film and silicon oxide film may change, resulting in a change in selectivity.

The purpose of the present invention is to provide an etching composition with high selectivity that can selectively remove the nitride film while minimizing the etching rate of the oxide film and does not have problems such as generation of particles that adversely affect device characteristics.

In addition, another object of the present invention is to provide an etching composition with excellent storage stability.

Furthermore, it is intended to provide a method of etching an insulating film and a method of manufacturing a semiconductor device using the etching composition.

The present invention is intended to provide an etching composition, and according to one embodiment of the present invention, an etching composition containing phosphoric acid and a silane compound represented by the following formula (1) is provided.

[Formula 1]

In Formula 1, R ₁ to R ₇ are each independently hydrogen ^, hydrocarbyl, or non-hydrocarbyl, and It is an anion, an anion derived from nitric acid, an anion derived from carbonic acid, or an anion derived from carboxylic acid, L _p is hydrocarbylene, p is 0 or 1, A is an n-valent radical, and n is an integer of 1 to 4.

^{The _ _ _} .

The substituted or unsubstituted C1-C20 hydrocarbyl group may be a substituted or unsubstituted C1-C20 alkyl group, or a substituted or unsubstituted C6-C20 aryl group.

The substituted C1-C20 hydrocarbyl group may be substituted with halogen.

The A may be hydrogen, halogen, hydrocarbylene, a radical whose binding site is N, a radical whose binding site is O, a radical whose binding site is S, or a radical whose binding site is P.

The hydrocarbylene may be C1-C20 alkyl, C1-C20 alkenyl, or C6-C20 aryl.

The radical whose binding site is N is *-NR ₁₁ R ₁₂ , *-NR ₁₃ -*, *-NR ₁₄ CONR ₁₅ -*, *-NR ₁₆ CSNR ₁₇ -* or It can be,

Here, R ₁₁ and R ₁₂ are independently hydrogen, C1-C20 alkyl, C1-C20 aminoalkyl, or CONH ₂ , R ₁₃ to R ₁₇ are independently hydrogen or C1-C20 alkyl, and L ₁ is C1-C20 alkyl. It's Ren.

The radical whose binding site is O may be *-O-*.

The radical whose binding site is S is *-SR ₂₀ , *-S-*, *-SS-*, or may be, where R ₂₀ is hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy.

The radical whose binding site is P is , , or may be, where R ₁₈ and R ₁₉ are independently hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy.

In Formula 1, n is 1, L _p is C1-C5 alkylene, p is 0 or 1, A is substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkenyl, *-NH ₂ , *-NH-(CH ₂ ) _l -NH ₂ , *-NH-CO-NH ₂ , *-(CH ₂ ) _m -C ₆ H ₅ , or *-SR ₂₀ , where R ₂₀ is hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy, and l and m may independently be integers from 0 to 10.

In Formula 1, n is 2, L _p is C1-C5 alkylene, p is 0 or 1, A is C1-C20 alkylene, *-NR ₁₃ -*, *-NR ₁₄ -CO-NR ₁₅ -*, *-O-*, *-S-*, *-SS-*, , , , or and R ₁₃ to R ₁₅ , R ₁₈ or R ₁₉ may independently be hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy.

In Formula 1, n is 3, L _p is C1-C5 alkylene, p is 0 or 1, and A is or It can be.

In Formula 1, n is 4, L _p is C1-C5 alkylene, p is 0 or 1, and A is , where L ₁ may be C1-C10 alkylene.

The silicon compound is preferably selected from the following structures.

(One), (2), (3), (4), (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (In the above formula, MsO represents methanesulfonate.)

The silane compound represented by the formula (1) preferably contains 0.001 to 5% by weight of the silicon compound based on the total weight of the etching composition, and the etching composition contains 70 to 90% by weight of phosphoric acid and silane represented by the formula (1). It may contain 0.001 to 5% by weight of the compound and the balance water.

The etching composition may further include a silane compound represented by the following formula (2).

[Formula 2]

In Formula 2, R ₅₁ to R ₅₄ are independently hydrogen, C ₁ -C ₂₀ hydrocarbyl, C ₁ -C ₂₀ heterohydrocarbyl, and R ₅₁ to R ₅₄ are each present or two or more It is in the form of rings connected to each other through hetero elements.

The etching composition may further include ammonium salt.

From another perspective, the present invention provides a method for etching an insulating film using the etching composition.

As another aspect, the present invention provides a method of manufacturing a semiconductor device including a method of etching the insulating film.

The present invention also provides a silane compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₇ are each independently hydrogen, hydrocarbyl, or non-hydrocarbyl, and X ^- is a halogen anion, a sulfonic acid anion, a phosphate anion, a hydrogen phosphate anion, Dihydrogen phosphate anion, sulfuric acid anion, hydrogen sulfate anion, nitrate anion, nitrite anion, carbonate anion, hydrogen carbonate anion, substituted or unsubstituted C1~C20 carboxylic acid anion, L _p is hydrocarbylene, and p is 0. or 1, A is hydrogen, halogen, or C1-C20 hydrocarbylene, and n is 1.

Formula 1 may be any one of the structures represented below.

(2), (3), (5)

The present invention also provides a silane compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₇ are each independently hydrogen, hydrocarbyl, or non-hydrocarbyl, and X ^- is a halogen anion, a sulfonic acid anion, a phosphate anion, a hydrogen phosphate anion, Dihydrogen phosphate anion, sulfuric acid anion, hydrogen sulfate anion, nitrate anion, nitrite anion, carbonate anion, hydrogen carbonate anion, substituted or unsubstituted carboxylic acid anion of C1-C20, Lp is hydrocarbylene of C1-C5 , p is 0 or 1, A is *-NR ₁₃ -*, *-NR ₁₄ -CO-NR ₁₅ -*, *-O-*, *-S-*, *-SS-*, , , , , or or , where R ₁₃ to R ₁₅ , R ₁₈ or R ₁₉ are independently hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy, and L ₁ is C1- It is C10 alkylene, and n is an integer of 2 to 4.

Formula 1 may be any one of the structures represented below.

(6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17)

The etching composition according to the present invention has a high etching selectivity of the nitride film to the oxide film.

In addition, using the etching composition of the present invention, it is possible to prevent damage to the quality of the oxide film or deterioration of electrical properties due to etching of the oxide film when removing the nitride film, prevent particle generation, and improve device characteristics.

1 and 2 are cross-sectional process views illustrating a method of etching an insulating film according to an embodiment of the present invention.

The present invention seeks to provide an etching composition, particularly an etching composition that has a high selectivity for selectively removing a nitride film while minimizing the etching rate of the oxide film, and also has excellent storage stability.

The etching composition of the present invention includes phosphoric acid, a silane compound, and water.

The phosphoric acid reacts with silicon nitride to etch the nitride, and the phosphoric acid reacts as shown in the following formula (1) to etch the silicon nitride.

3Si ₃ N ₄ + 27H ₂ O + 4H ₃ PO ₄ → 4(NH ₄ ) ₃ PO ₄ + 9SiO ₂ H ₂ O (1)

For example, the phosphoric acid may be an aqueous phosphoric acid solution containing phosphoric acid at a concentration of 75 to 85%. The water used in the phosphoric acid aqueous solution is not particularly limited, but deionized water can be used.

The phosphoric acid is preferably included in an amount of 70 to 90% by weight based on the total weight of the etching composition. If it is less than 70% by weight, there is a problem that the nitride film is not easily removed, and if it exceeds 90% by weight, a high selectivity to the nitride film cannot be obtained.

The etching composition of the present invention includes a silane compound as an etchant additive. The silane compound may be, for example, a silane compound represented by the following formula (1).

In Formula 1, R ₁ to R ₇ are each independently hydrogen, hydrocarbyl, or non-hydrocarbyl. The hydrocarbyl or non-hydrocarbyl is halogen, substituted or unsubstituted C1-C20 hydrocarbyl group, C1-C20 alkoxy group, carboxyl group, carbonyl group, nitro group, tri(C1-C20)alkylsilyl group, phosphoryl group or It could be cyano group. The substituted or unsubstituted C1-C20 hydrocarbyl group may be a substituted or unsubstituted C1-C20 alkyl group, or a substituted or unsubstituted C6-C20 aryl group. The substitution is not limited to this, but may be substituted with halogen.

In Formula 1 ^, It may be a nitric acid-derived anion, a carbonate-derived anion such as a carbonate anion or a hydrogen carbonate anion, or a carboxylic acid-derived anion of a substituted or unsubstituted C1-C20 carboxylic acid anion.

^{For example , the} It can be.

The Lp may be hydrocarbylene, and in this case, p is 1 or 1. The Lp may be C1-C5 hydrocarbylene, specifically C1-C5 alkylene, and more specifically C1-C3 alkylene.

The A represents an n-valent radical that is an integer of 1 to 4. For example, A may be hydrogen, halogen, hydrocarbylene, a radical with a bonding site of N, a radical with a bonding site of O, a radical with a bonding site of S, or a radical with a bonding site of P, etc.

For example, A may be hydrogen and may be a halogen such as F, Cl, Br, or I. At this time, n is an integer of 1.

The hydrocarbylene may be substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkenyl, or substituted or unsubstituted C6-C20 aryl. More specifically, for example, *- It may be CH ₃ , *-(CH ₂ ) ₃ , *-(CH ₂ ) ₂ CH ₃ , *-(CH ₂ ) ₇ CH ₃ , *-CH ₂ CH(CH ₃ ) ₂ , *-CHCH ₂ , phenyl, etc. there is. At this time, n is an integer of 1. Furthermore, when n is 2, it may be substituted or unsubstituted C1-C20 alkenyl such as *-(CH ₂ ) ₂ -*.

As a radical where the binding site is N, for example, when n is 1, A is an unsubstituted amine such as *-NH ₂ , or *-NH(CH ₂ ) ₂ NH ₂ or NHCONH ₂ Examples include *-NR ₁₁ R ₁₂ of the same substituted amine. Additionally, when n is 2, *-NR ₁₃ -* such as *-NH-*, *-NR ₁₄ CONR ₁₅ -* such as *-NHCONH-*, *-NR ₁₆ such as *-NHCSNH-* CSNR ₁₇ -*, etc. may be mentioned. Furthermore, in the case where n is 4, can be mentioned.

Here, R ₁₁ and R ₁₂ may independently be hydrogen, C1-C20 alkyl, C1-C20 aminoalkyl, or CONH ₂ , etc., R ₁₃ to R ₁₇ may independently be hydrogen or C1-C20 alkyl, and L ₁ is It may be C1-C20 alkylene.

The radical whose binding site is O may be *-O-*.

The radical in which the binding site is S has n of 1 and may be *-SR ₂₀ , where R ₂₀ is hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl (C1- C20) alkoxy. In addition, for radicals whose binding site is S, when n is 2, *-S-*, *-SS-*, or It can be.

On the other hand, the radical whose binding site is P is , , or may be mentioned, where n is an integer of 2 or 3. Here, R ₈ and R ₉ are independently hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl (C1-C20)alkoxy.

In the present invention, the silane compound of formula 1 when n is 1 is, for example, Lp is C1-C5 alkylene, preferably C1-C3 alkylene, p is 0 or 1, and A is hydrogen. , halogen, substituted or unsubstituted C1-C20alkyl, substituted or unsubstituted C1-C20alkenyl, *-NH ₂ , *-NH-(CH ₂ ) _l -NH ₂ , *-NH-CO-NH ₂ , *-C ₆ H ₅ , *-(CH ₂ ) _m -C ₆ H ₅ or *-SR ₂₀ , where R ₂₀ is hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl ( C1-C20) alkoxy, and l and m may independently be a silane compound that is an integer of 1 to 10.

In addition, in the silane compound of formula 1 when n is 2, for example, Lp is C1-C5 alkylene, preferably C1-C3 alkylene, p is 0 or 1, and A is C1-C20. Alkylene, *-NR ₁₃ -*, *-NR ₁₄ -CO-NR ₁₅ -*, *-O-*, *-S-*, *-SS-*, , , , or and R ₁₃ to R ₁₅ , R ₁₈ and R ₁₉ may independently be hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20) alkyl (C1-C20) alkoxy silane compound.

In addition, the silane compound of Formula 1 where n is 3, for example, Lp is C1-C5 alkylene, preferably C1-C3 alkylene, p is 0 or 1, and A is or It may be a phosphorus silane compound.

Furthermore, in the silane compound of formula 1 when n is 4, for example, Lp is C1-C5 alkylene, preferably C1-C3 alkylene, p is 0 or 1, and A is and; Here, L ₁ may be a silane compound of C1-C10 alkylene.

More specifically, the silane compound represented by Formula 1 may be, for example, any one of the silane compounds represented by the following structural formulas 1 to 17.

(One), (2), (3), (4), (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (In the above formula, MsO represents methanesulfonate, an example of C1-C20 alkylsulfonate.)

The oxygen contained in the above silane compound protects the oxide film by bonding to the surface of the oxide film, and the oxygen contained in the silane compound can hydrogen bond to the surface of the oxide film, thereby etching the oxide film while the nitride is etched in the etching composition. This can be minimized.

In addition, the above silane compound is a cyclic silane compound and can exist in the most stable form in the etching composition, and therefore can significantly increase the etching selectivity compared to the commonly used short-chain silicon additive. . Furthermore, by including the above-mentioned cyclic compound, the structural stability of the active silicon-based additive in the etching composition is improved, and the etching rate of the silicon oxide film can be continuously maintained.

The silane compound proposed in the present invention can effectively protect the silicon oxide film even when added in a small amount to the etching composition, thereby increasing the etching selectivity of nitride over the oxide film. The silane compound can be added in an amount of 0.001 to 5% by weight based on the total weight of the etching composition. If the silane compound is used in an amount of less than 0.001% by weight, it is difficult to obtain a high selectivity effect of the nitride for the oxide film, and if it is more than 5% by weight, the silane compound may gel, which is not desirable. For example, the silane additive is greater than 0.001, 0.005, 0.007, 0.01, 0.03, 0.05, 0.07, 0.1, 0.15 or 0.2% by weight and less than or equal to 5, 4.5, 4, 3.5, 3, 2.5, 2 or 1% by weight. It can be included in amounts within the range.

Silane compounds used as additives for etching compositions are characterized by low solubility. If a silane-based additive that does not have adequate solubility is used in the etching composition or the composition ratio is not adjusted to an appropriate level, precipitation and abnormal growth of silicon-based particles occur within the etching composition. These particles may remain on the silicon substrate, causing defects in devices implemented on the substrate, or may remain in equipment (eg, filters) used in the etching or cleaning process, causing equipment failure.

The etching composition of the present invention improves selectivity for nitrides by suppressing etching of oxides using the silane compound as described above, and suppresses silica production, thereby suppressing particle production and improving storage stability.

Meanwhile, in Equation 1, SiO ₂ H ₂ O usually precipitates on the surface of the oxide film and may exhibit an abnormal growth phenomenon that can increase the thickness of the oxide film. In particular, when the nitride etching process progresses cumulatively in the etching composition, the concentration of SiO ₂ H ₂ O in the etching composition may increase, and this increase in the concentration of SiO ₂ H ₂ O increases the degree of occurrence of abnormal growth. can do. That is, even if abnormal growth due to SiO ₂ H ₂ O does not occur in the initial etching composition, the frequency of abnormal growth increases as the number of cumulative processes increases. However, when the silane compound according to the present invention is included, the occurrence of such abnormal growth phenomenon can be suppressed.

In the etching composition of the present invention, the remainder is a solvent. The solvent is not particularly limited, but may be water.

The etching composition of the present invention may further include a silane compound represented by the following formula (2).

In Formula 2, R ₅₁ to R ₅₄ are independently hydrogen, C1-C20 hydrocarbyl, or C1-C20 heterohydrocarbyl, and R ₅₁ to R ₅₄ are each present or two or more of them are connected to each other through a hetero atom. It is in a ring shape. For example, it may be hydrogen, C1-C20 alkyl, or C1-C20 heteroalkyl. At this time, the hetero element is not particularly limited, but may be, for example, N, S, O, P, etc.

The silane compound represented by Formula 2 may be included in an amount of 0.005 to 1% by weight based on the total weight of the etching composition.

Furthermore, ammonium salt can also be added to the etching composition of the present invention. Ammonium salt can prevent gelation of the etching composition and can be added in an amount of 0.001 to 10% by weight based on the total weight. If added in less than 0.001% by weight, the effect of improving physical properties in reducing gelation is minimal, and if added in excess of 10% by weight, ammonium salt may cause gelation.

The ammonium salt is a compound having an ammonium ion, and those commonly used in the field to which the present invention pertains can also be suitably used in the present invention. Such ammonium salts are not limited thereto, but include, for example, ammonia water, ammonium chloride, ammonium acetic acid, ammonium phosphate, ammonium peroxydisulfate, ammonium sulfate, and ammonium hydrofluoric acid. Any one of these may be used alone. Of course, it is possible to use a mixture of two or more.

Furthermore, the etching composition of the present invention may further include any additives commonly used in the art to further improve etching performance. Additives include surfactants, metal ion sequestrants, and corrosion inhibitors.

The etching composition of the present invention is used to selectively etch and remove a nitride film from a semiconductor device including an oxide film and a nitride film, and the nitride film may include a silicon nitride film, for example, a SiN film, a SiON film, etc.

In addition, the oxide film may be a silicon oxide film, such as a Spin On Dielectric (SOD) film, a High Density Plasma (HDP) film, a thermal oxide film, a Borophosphate Silicate Glass (BPSG) film, a Phospho Silicate Glass (PSG) film, or a BSG ( Boro Silicate Glass (PSZ) film, PSZ (Polysilazane) film, FSG (Fluorinated Silicate Glass) film, LPTEOS (Low Pressure Tetra Ethyl Ortho Silicate) film, PETEOS (Plasma Enhanced Tetra Ethyl Ortho Silicate) film, HTO (High Temperature Oxide) film, MTO (Medium Temperature Oxide) film, USG (Undopped Silicate Glass) film, SOG (Spin On Glass) film, APL (Advanced Planarization Layer) film, ALD (Atomic Layer Deposition) film, PE-oxide film (Plasma Enhanced oxide), O3 -It may be at least one film selected from the group consisting of a TEOS (O3-Tetra Ethyl Ortho Silicate) film and a combination thereof.

The etching process using the etching composition of the present invention may be performed by a wet etching method, such as an immersion method or a spraying method.

An example of an etching process using the etching composition of the present invention is schematically shown in Figures 1 and 2. 1 and 2 are cross-sectional views showing, as an example, a device separation process for a flash memory device.

First, as shown in FIG. 1, a tunnel oxide film 11, a polysilicon film 12, a buffer oxide film 13, and a pad nitride film 14 are sequentially formed on the substrate 10, and then the polysilicon film 12 is formed. ), the buffer oxide film 13 and the pad nitride film 14 are selectively etched to form a trench. Next, the SOD oxide film 15 is formed until the trench is gap-filled, and then a CMP process is performed on the SOD oxide film 15 using the pad nitride film 14 as a polishing stop film.

Next, as shown in FIG. 2, the pad nitride film 14 is removed by wet etching using a phosphoric acid solution, and then the buffer oxide film 13 is removed through a cleaning process. As a result, the device isolation film 15A is formed in the field region.

During the etching process, the process temperature may range from 50 to 300°C, preferably from 100 to 200°C, and more preferably from 156°C to 163°C. The appropriate temperature is necessary in consideration of other processes and other factors. It may change depending on.

According to the method of manufacturing a semiconductor device including an etching process performed using the etching composition of the present invention, selective etching of the nitride film is possible when the nitride film and the oxide film are alternately stacked or mixed. In addition, the stability and reliability of the process can be secured by preventing the generation of particles, which was a problem in the conventional etching process.

Therefore, this method can be efficiently applied to various processes that require selective etching of the nitride film with respect to the oxide film in the semiconductor device manufacturing process.

Example

Hereinafter, the present invention will be described in more detail through examples. The following example is an example of the present invention, and the present invention is not limited thereto.

Synthesis Example 1

Add 29.1 g of tris(2-hydroxyethyl)methylammonium iodide, 20.7 g of (N,N-dimethylaminopropyl)trimethoxysilane, and 30 mL of toluene to a 100 mL round bottom flask, then raise the temperature to 130°C and 24 °C. It was stirred for some time.

Afterwards, methanol was removed under reduced pressure, the mixture was stirred for an additional 2 hours, cooled to room temperature, and filtered to obtain a white solid.

The white solid was purified through toluene re-slurry to purify the silane additive 1[1-[(dimethylamino)methyl]-5-methyl-2,8,9-trioxa-5-azonia-1- 3.1 g of sylabicyclo[3,3,3]undecane iodide] was synthesized.

¹ H-NMR (CDCl ₃ ) 4.38~4.07(m, 6H), 3.90(t, J =10.7 Hz, 1H), 3.58(t, J =8.9 Hz, 1H), 3.56~3.48(m, 4H), 2.87(s, 3H), 2.38(s, 6H), 1.94(s, 2H)

Synthesis Example 2

26.1 g of tris(2-hydroxyethyl)methylammonium phosphate, 13.6 g of methyltrimethoxysilane, and 30 mL of toluene were added to a 100 mL round bottom flask, then the temperature was raised to 130°C and stirred for 24 hours.

Afterwards, methanol was removed under reduced pressure, the mixture was stirred for an additional 2 hours, cooled to room temperature, and filtered to obtain a white solid.

The white solid was mixed with the silane additive 2[1-methyl-5-methyl-2,8,9-trioxa-5-azonia-1-silabicyclo[3,3,3] purified through toluene reslurry. Khan phosphate] 4.2g was synthesized.

¹ H-NMR (CDCl ₃ ) 4.35~4.26(m, 1H), 4.25~4.13(m, 3H), 4.11~3.98(m, 2H), 3.71~3.54(m, 3H), 3.53~3.43(m, 3H), 2.86(s, 3H), 0.47(s, 3H)

Synthesis Example 3

25.9 g of tris(2-hydroxyethyl)methylammonium methanesulfonate, 13.6 g of methyltrimethoxysilane, and 30 mL of toluene were added to a 100 mL round bottom flask, then the temperature was raised to 130°C and stirred for 24 hours.

Afterwards, methanol was removed under reduced pressure, the mixture was stirred for an additional 2 hours, cooled to room temperature, and filtered to obtain a white solid.

The white solid was mixed with the silane additive 3[1-methyl-5-methyl-2,8,9-trioxa-5-azonia-1-silabicyclo[3,3,3] purified through toluene reslurry. Cannes methanesulfonate] 4.5g was synthesized.

(MsO stands for methanesulfonate.)

¹ H-NMR (CDCl ₃ ) 4.35~4.26(m, 1H), 4.25~4.13(m, 3H), 4.11~3.98(m, 2H), 3.82~3.65(m, 3H), 3.64~3.50(m, 3H), 2.90(s, 3H), 0.47(s, 3H)

Synthesis Example 4

Add 29.1 g of tris(2-hydroxyethyl)methylammonium iodide, 18.2 g of trimethoxy[(methylthio)methyl]silane, and 30 ml of toluene to a 100 ml round bottom flask, then heat to 130°C for 24 hours. It was stirred.

Afterwards, methanol was removed under reduced pressure, the mixture was stirred for an additional 2 hours, cooled to room temperature, and filtered to obtain a white solid.

The white solid was purified through toluene reslurry with the silane additive 4[5-methyl-1-[(methylthio)methyl]-2,8,9-trioxa-5-azonia-1-silabicyclo[ 2.7g of [3,3,3]undecane iodide] was synthesized.

¹ H-NMR (CDCl ₃ ) 4.38~4.28(m, 1H), 4.22~4.08(m, 3H), 3.90(t, J =10.6 Hz, 1H), 3.59(t, J =8.9 Hz, 1H), 3.56~3.48(m, 4H), 2.87(s, 3H), 2.54(s, 2H), 2.07(s, 3H)

Synthesis Example 5

19.9 g of tris(2-hydroxyethyl)methylammonium chloride, 19.8 g of (3-chloropropyl)trimethoxysilane, and 30 mL of toluene were added to a 100 mL round bottom flask, then the temperature was raised to 130°C and stirred for 24 hours.

Afterwards, methanol was removed under reduced pressure, the mixture was stirred for an additional 2 hours, cooled to room temperature, and filtered to obtain a white solid.

The white solid was mixed with the silane additive 5[1-(3-chloropropyl)-5-methyl-2,8,9-trioxa-5-azonia-1-silabicyclo[3, 2.0 g of [3,3]undecane chloride] was synthesized.

¹ H-NMR(CDCl ₃ ) 4.37~4.23(m, 2H), 4.23~4.07(m, 4H), 3.89(t, J =10.7 Hz, 1H), 3.59(t, J =8.8 Hz, 1H), 3.56~3.43(m, 4H), 3.48(t, J =7.6 Hz, 2H), 2.89(s, 3H), 1.96(quint, J =7.5 Hz, 2H), 1.08(t, J =7.5 Hz, 2H) )

Example 1

A substrate with a silicon oxide film (SiOx) deposited to a thickness of 500 Å (angstrom) and a silicon nitride film (SiN) to a thickness of 5000 Å were formed on a semiconductor wafer.

As shown in Table 1, an etching composition was prepared by adding 99.5% by weight of 85% phosphoric acid and 0.5% by weight of silane additive 1 and mixing to 100% by weight.

The etching composition was placed in a round flask and heated for 60 minutes to raise the temperature to 158°C, and then the silicon wafer was immersed for 720 seconds and 6000 seconds to perform an etching process.

After selectively etching the patterned silicon wafer surface, the thickness of the silicon oxide and nitride films before and after etching is measured using ellipsometry, a thin film thickness measurement equipment (NANO VIEW, SEMG-1000), and from this, The etch rate of the silicon oxide film (SiN E/R, Å/min) and the etch rate of the nitride film (SiN E/R, Å/min) and selectivity were calculated. The results are shown in Table 1.

The selectivity ratio represents the ratio of the nitride film etching rate to the oxide film etching rate, and is a value calculated by dividing the difference between the initial value and the film thickness after etching by the etching time (minutes).

Examples 2 to 5

The etching process was performed in the same manner as in Example 1 except that silane additives 2 to 5 were used, and the etching rate of the silicon oxide film and the etching rate and selectivity of the nitride film were calculated, and the results are shown in Table 1.

Comparative Example 1

The etching process was performed in the same manner as in Example 1 except that 3-Aminopropylsilanetriol was used as an additive, and the etching rate of the silicon oxide film and the etching rate and selectivity of the nitride film were calculated, and the results are shown in Table 1.

Composition (% by weight) process temperature
(℃) SiN E/R
(Å/min) SiO E/R
(Å/min) selection fee 85% phosphoric acid Silane additive type and content Comparative Example 1 99.5 3-Aminopropylsilanetriol, 0.5wt% 158 68.3 0.32 213 Example 1 99.5 Silane additive 1, 0.5wt% 158 87.5 0.17 515 Example 2 99.5 Silane additive 2, 0.5wt% 158 95.8 0.05 1916 Example 3 99.5 Silane additive 3, 0.5wt% 158 93.8 0.07 1340 Example 4 99.5 Silane additive 4, 0.5wt% 158 88.6 0.15 591 Example 5 99.5 Silane additive 5, 0.5wt% 158 90.7 0.12 756

As can be seen from Table 1, when the cyclic silane compounds of silane additives 1 to 5 were applied to the etching composition as an additive to the etching composition, the etching selectivity was significantly higher than that of Comparative Example 1. In addition, in terms of the etching rate (SiN E/R) of the silicon nitride film, it showed a significantly superior effect compared to the etching composition of Comparative Example 1, confirming that an etching composition optimized for the etching process of the silicon nitride film can be provided.

From these results, it can be seen that when the silane compound proposed in the present invention is used as an additive, the stability of the active silicon-based structure is improved compared to the short-chain silane compound of Comparative Example 1. Therefore, the etch rate of the silicon nitride film, It was confirmed that an etching composition that can improve etching process efficiency by improving etching selectivity and etching stability can be provided.

Claims (25)

An etching composition comprising phosphoric acid and a silane compound represented by the following formula (1).
[Formula 1]

In Formula 1,
R ₁ to R ₇ are each independently hydrogen, hydrocarbyl, or non-hydrocarbyl,
^and
L _p is hydrocarbylene, p is 0 or 1,
A is an n-valent radical, and n is an integer from 1 to 4. The etching composition of claim 1, wherein X ^- is Cl ^- , I ^-, or Br ^- . The etching composition of claim 1, wherein X ^- is a C1-C20 alkylsulfonate anion, dihydrophosphate sulfate anion, or bisulfate anion. The etching composition of claim 1, wherein X ^- is a nitrate anion or a nitrite anion. The etching composition of claim 1, wherein A is hydrogen, halogen, hydrocarbylene, a radical having an N binding site, a radical having an O binding site, a radical having a binding site S, or a radical having a binding site P. The etching composition of claim 4, wherein the hydrocarbylene is C1-C20 alkyl, C1-C20 alkenyl, or C6-C20 aryl. The method of claim 5, wherein the radical where the binding site is N is *-NR ₁₁ R ₁₂ , *-NR ₁₃ -*, *-NR ₁₄ CONR ₁₅ -*, *-NR ₁₆ CSNR ₁₇ -* or Phosphorus etching composition.
Here, R ₁₁ and R ₁₂ are independently hydrogen, C1-C20 alkyl, C1-C20 aminoalkyl or CONH ₂ , R ₁₃ to R ₁₇ are independently hydrogen or C1-C20 alkyl, and L ₁ is C1-C20 alkyl. It's Ren. The etching composition according to claim 4, wherein the O radical at the binding site is *-O-*. The method of claim 5, wherein the radical where the binding site is S is *-SR ₂₀ , *-S-*, *-SS-*, or Phosphorus etching composition.
Here, R ₂₀ is hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy. The method of claim 5, wherein the radical where the binding site is P is , , or Phosphorus etching composition.
Here, R ₁₈ and R ₁₉ are independently hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy. According to paragraph 1,
n is 1,
L _p is C1-C5 alkylene, p is 0 or 1,
A is hydrogen, halogen, substituted or unsubstituted C1-C20alkyl, substituted or unsubstituted C1-C20alkenyl, *-NH ₂ , *-NH-(CH ₂ ) _l -NH ₂ , *-NH-CO -NH ₂ , *-(CH ₂ ) _m -C ₆ H ₅ or *-SR ₂₀ etching composition.
Here, R ₂₀ is hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy, and l or m is independently an integer from 0 to 10. According to paragraph 1,
n is 2,
L _p is C1-C5 alkylene, p is 0 or 1,
A is C1-C20 alkylene, *-NR ₁₃ -*, *-NR ₁₄ -CO-NR ₁₅ -*, *-O-*, *-S-*, *-SS-*, , , , or Phosphorus etching composition.
Here, R ₁₃ to R ₁₅ , R ₁₈ or R ₁₉ are independently hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20)alkyl(C1-C20)alkoxy. According to paragraph 1,
n is 3,
L _p is C1-C5 alkylene, p is 0 or 1,
A is or Phosphorus etching composition. According to paragraph 1,
n is 4,
L _p is C1-C5 alkylene, p is 0 or 1,
A is Phosphorus etching composition.
Here, L ₁ is C1-C10 alkylene. According to paragraph 1,
The etching composition wherein the silane compound is selected from the following structures.
(One), (2), (3), (4), (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (In the above formula, MsO ^- represents methanesulfonate.) The etching composition according to any one of claims 1 to 15, wherein the silane compound represented by Chemical Formula (1) contains 0.001 to 5% by weight of the silicon compound based on the total weight of the etching composition. The etching composition according to any one of claims 1 to 15, wherein the etching composition includes 70 to 90% by weight of phosphoric acid, 0.001 to 5% by weight of the silane compound represented by Chemical Formula 1, and the balance water. The etching composition of claim 16, further comprising a silane compound represented by the following formula (2).
[Formula 2]

In Formula 2, R ₅₁ to R ₅₄ are independently hydrogen, C1-C20 hydrocarbyl, or C1-C20 heterohydrocarbyl, and R ₅₁ to R ₅₄ each exist or are formed through two or more hetero atoms. It is in the form of a ring connected to each other. The etching composition of claim 16, further comprising an ammonium salt. A method of etching an insulating film using the etching composition of any one of claims 1 to 15. A method of manufacturing a semiconductor device comprising the etching method of the insulating film of claim 20. A silane compound represented by the following formula (1).
[Formula 1]

In Formula 1,
R ₁ to R ₇ are each independently hydrogen, hydrocarbyl, or non-hydrocarbyl,
^- is a carboxylic acid anion,
L _p is hydrocarbylene, p is 0 or 1,
A is hydrogen, halogen or C1-C20 hydrocarbylene,
n is 1. The silane compound according to claim 22, wherein Chemical Formula 1 is expressed by the following structure.
(2), (3), (5) (In the above formula, MsO ^- is methanesulfonate.) A silane compound represented by the following formula (1).
[Formula 1]

In Formula 1,
R ₁ to R ₇ are each independently hydrogen, hydrocarbyl, or non-hydrocarbyl,
^- is a carboxylic acid anion, Lp is a C1-C5 hydrocarbylene, p is 0 or 1,
A is *-NR ₁₃ -*, *-NR ₁₄ -CO-NR ₁₅ -*, *-O-*, *-S-*, *-SS-*, , , , , or or ego,
Here, R ₁₃ to R ₁₅ , R ₁₈ or R ₁₉ are independently hydrogen, C1-C20 alkyl, C6-C20 aryl, or (C1-C20) alkyl (C1-C20) alkoxy, and L ₁ is C1-C10 alkyl. It's Ren,
n is an integer from 2 to 4. The silane compound according to claim 24, wherein Chemical Formula 1 is expressed by the following structure.
(6), (7), (8), (9), (10), (11), (12), (13), (14), (15), (16), (17)