JP7397628B2 - Silicon substrate etching solution and method for manufacturing semiconductor devices using the same - Google Patents

Description

The present invention relates to a silicon substrate etching solution and a method of manufacturing a semiconductor device using the same, and more specifically, by adjusting the concentration of a silane compound (silicon) in the silicon substrate etching solution, the present invention can be applied during etching of a silicon nitride film. The present invention relates to a silicon substrate etching solution that can improve the etching selectivity of a silicon oxide film to a silicon nitride film, and a semiconductor device manufacturing method including an etching process performed using the same.

Currently, there are various methods for etching silicon nitride and silicon oxide, but dry etching and wet etching are the most commonly used methods.

Dry etching is usually an etching method that uses gas, and has the advantage of being superior to wet etching in terms of isotropy, but it has lower productivity and is more expensive than wet etching. Wet etching is a widely used method.

Generally, as a wet etching method, a method using phosphoric acid as an etching solution is well known. At this time, if only pure phosphoric acid is used to etch the silicon nitride film, as devices become smaller, not only the silicon nitride film but also the silicon oxide film will be etched, resulting in various defects and pattern abnormalities. Therefore, it is necessary to further reduce the etching rate of the silicon oxide film.

The present invention increases the concentration of a silane compound (silicon) in a silicon substrate etching solution, lowers the etching rate for a silicon oxide film, and improves the etching selectivity ratio of a silicon oxide film to a silicon nitride film. The purpose is to provide a substrate etching solution.

Another object of the present invention is to provide a silicon substrate etching solution that can reduce the etching rate of not only a silicon oxide film but also a silicon nitride film or prevent the generation of silicon-based particles.

A further object of the present invention is to provide a method for manufacturing a semiconductor device including an etching step performed using the silicon substrate etching solution described above.

In order to solve the above-mentioned technical problems, one aspect of the present invention provides a silicon substrate etching solution containing an inorganic acid aqueous solution and a silicon additive represented by the following formula.

[Chemical formula 1]

here,
Z is represented by the following chemical formula 2,

[Chemical 2]

X ₁ and X ₂ are each independently oxygen or sulfur,

R ₁ to R ₄ are each independently hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heteroalkyl containing at least one heteroatom, C ₂ -C ₁₀ alkenyl, C ₂ - _C10 alkynyl, C1 _{- C10} haloalkyl _, C1- _C10 aminoalkyl, aryl, heteroaryl, aralkyl and hydroxy, amino, halogen, sulfone, phosphonic, phosphoric, thiol, alkoxy, amide, ester, selected from acid anhydrides, acyl halides, cyanos, carboxyls and azoles;

Y ₁ to Y ₄ are each independently hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heteroalkyl containing at least one heteroatom, C ₂ -C ₁₀ alkenyl, C ₂ - _C10 alkynyl, C1 _{- C10} haloalkyl _, C1- _C10 aminoalkyl, aryl, heteroaryl, aralkyl and hydroxy, amino, halogen, sulfone, phosphonic, phosphoric, thiol, alkoxy, amide, ester, selected from acid anhydrides, acyl halides, cyanos, carboxyls and azoles;

n is a constant number between 1 and 5.

Further, according to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device including an etching step performed using the silicon substrate etching solution described above.

In the silicon substrate etching solution according to the present invention, the silicon additive can be decomposed into an amide (for example, when X ₁ and X ₂ in Chemical Formula 1 are oxygen) and a silane compound (for example, silic acid) under the etching conditions. By increasing the concentration of the silane compound (silicon) in the silicon substrate etching solution, the etching rate of the silicon oxide film can be lowered.

At this time, the silicon additive used in the present application is a cyclic compound, and the decomposition rate of the silane moiety and the amide moiety is slower than that of a compound in which the silane moiety and the amide moiety are bonded in a chain. As a result, the rate of release of the silane compound into the silicon etching solution can be delayed.

This prevents the concentration of silane compounds (silicon) in the silicon substrate etching solution from increasing rapidly, reducing the etching rate not only for the silicon oxide film but also for the silicon nitride film, so the etching efficiency does not decrease. You can do it like this.

Further, it is possible to prevent an excessive amount of silane compound in the silicon substrate etching solution from acting as a source of silicon-based particles.

The advantages and features of the invention, and the manner in which they are achieved, will become clearer with reference to the examples described below. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms. However, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art to which the invention pertains. It is only defined by the category of the term.

Below, the silicon substrate etching solution according to the present invention will be explained in detail.

According to one aspect of the present invention, a silicon substrate etching solution is provided that includes an aqueous inorganic acid solution and a silicon additive.

The silicon substrate to be etched with the silicon substrate etching solution according to the present invention preferably contains at least a silicon nitride film, and may contain both a silicon oxide film and a silicon nitride film. Further, in the case of a silicon substrate containing both a silicon oxide film and a silicon nitride film, the silicon oxide film and the silicon nitride film may be alternately stacked or stacked in different regions.

Here, the silicon oxide film is classified into SOD (Spin On Dielectric) film, HDP (High Density) film depending on the application and the type of material.
Plasma film, thermal oxide film, BPSG (Borophosphate) film
Silicate Glass) film, PSG (Phospho Silicate Glass) film, BSG (Boro
Silicate Glass) membrane, PSZ (Polysilazane) membrane, FSG (Fluorinated Silicate) membrane
Glass) membrane, LP-TEOS (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) film
Deposition film, PE-oxide film (Plasma Enhanced oxide) or O ₃ -TEOS (O ₃ -Tetra Ethyl
Ortho Silicate) etc. may be mentioned.

Here, the inorganic acid aqueous solution may be an aqueous solution containing at least one inorganic acid selected from sulfuric acid, nitric acid, phosphoric acid, silicic acid, hydrofluoric acid, boric acid, hydrochloric acid, and perchloric acid. In addition to the above-mentioned inorganic acids, phosphoric anhydride, pyrophosphoric acid, or polyphosphoric acid may also be used.

The inorganic acid aqueous solution is a component that maintains the pH of the etching solution and suppresses various forms of silane compounds present in the etching solution from changing into silicon-based particles.

In one embodiment, the inorganic acid aqueous solution is preferably included in an amount of 60 to 90 parts by weight per 100 parts by weight of the silicon substrate etching solution.

If the content of the inorganic acid aqueous solution is less than 60 parts by weight with respect to 100 parts by weight of the silicon substrate etching solution, the etching rate of the silicon nitride film may decrease, and the silicon nitride film may not be etched sufficiently or the silicon nitride film may be etched. There is a risk that process efficiency will decrease.

On the other hand, if the content of the inorganic acid aqueous solution exceeds 90 parts by weight with respect to 100 parts by weight of the silicon substrate etching solution, not only the etching rate of the silicon nitride film increases too much, but also the silicon oxide film is etched quickly. The selectivity of the silicon oxide film to the silicon nitride film may be reduced, and the etching of the silicon oxide film may cause defects in the silicon substrate.

A silicon substrate etching solution according to an embodiment of the present invention may include a silicon additive represented by the following formula 1 to increase the selectivity of silicon oxide to silicon nitride.

[Chemical formula 1]

here,
Z is represented by the following chemical formula 2,

[Chemical 2]

Here, X ₁ and X ₂ are each independently oxygen or sulfur, and R ₁ to R ₄ are each independently hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, at least one hetero Atoms containing C ₂ -C ₁₀ heteroalkyl, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, aralkyl and hydrophilic action Y ₁ -Y ₄ are each independently hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heteroalkyl containing at least one heteroatom, C ₂ - selected from C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, aralkyl and hydrophilic functional groups.

The hydrophilic functional group bonded to a silicon atom means a hydroxy group or a functional group that can be substituted by a hydroxy group under the pH conditions of an aqueous inorganic acid solution.

Here, non-limiting examples of functional groups that can be substituted with hydroxyl groups under the pH conditions of the inorganic acid aqueous solution include amino, halogen, sulfone, phosphonic, phosphoric, thiol, alkoxy, amide, ester, and acid anhydride. halogenated acyl, cyano, carboxyl, and azole, and is not necessarily limited to the above-mentioned functional groups, but is understood to include any functional group that can be substituted with a hydroxyl group under the pH conditions of an aqueous inorganic acid solution. Must.

In the silicon substrate etching solution according to the present invention, silicon additives include amide (for example, when X _{1 and} The silane compound can be decomposed into a compound (e.g., silic acid), and the silane compound can lower the etching rate for the silicon oxide film by increasing the concentration of the silane compound (silicon) in the silicon substrate etching solution.

At this time, the silicone additive used in the present application is a cyclic compound, and the decomposition rate of the silane moiety and amide moiety is slower than that of a compound in which the silane moiety and the amide moiety are linked in a chain. , the release rate of the silane compound into the silicon etching solution can be delayed.

This prevents the concentration of silane compounds (silicon) in the silicon substrate etching solution from increasing rapidly, reducing the etching rate not only for the silicon oxide film but also for the silicon nitride film, so the etching efficiency does not decrease. You can do it like this.

Furthermore, by adjusting the decomposition rate of the silicon additive, it is possible to prevent the silane compound (silicon) from acting as a source of silicon-based particles.

Further, the number of repeating units Z represented by Chemical Formula 2 is preferably 1 to 5 (ie, n is a constant between 1 and 5). In the absence of the repeating unit Z represented by Chemical Formula 2, the silicon additive represented by Chemical Formula 1 forms a four-atomic ring, which increases instability due to strain and may easily decompose. Furthermore, when the number of repeating units represented by Chemical Formula 2 exceeds 5, the ring size of the silicon additive represented by Chemical Formula 1 becomes too large and may be easily decomposed.

Furthermore, a silicon substrate etching solution according to another embodiment of the present invention may further include a silicon additive represented by Chemical Formula 3 and/or Chemical Formula 4.

[Chemical 3]

where R ₅ to R ₈ are each independently a hydrophilic functional group or hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ hetero atom containing at least one heteroatom; The functional group is selected from alkyl, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, aralkyl, silyloxy and siloxane.

[C4]

Here, R ₉ to R ₁₄ are each independently a hydrophilic functional group, or hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, or C ₂ -C ₁₀ containing at least one heteroatom. a functional group selected from heteroalkyl, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, aralkyl, silyloxy and siloxane; , n are constants from 1 to 5.

In this application, halogen means fluoro (-F), chloro (-Cl), bromo (-Br) or iodo (-I), and haloalkyl means an alkyl substituted with the above-mentioned halogen. For example, halomethyl means methyl in which at least one of the hydrogens of methyl is replaced with a halogen (-CH ₂ X, -CHX ₂ or -CX ₃ ).

Furthermore, alkoxy in this application refers to both an -O- (alkyl) group and an -O- (unsubstituted cycloalkyl) group, and includes one or more ether groups and 1 to 10 carbon atoms. It is a straight-chain or branched-chain hydrocarbon.

Specifically, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy, 1,2-dimethylbutoxy, cyclopropyloxy, cyclobutyloxy, cyclopentyl It includes, but is not limited to, oxy, cyclohexyloxy, and the like.

When R _a (where a is a constant selected from 1 to 4) is alkenyl or alkynyl, the sp ² -hybridized carbon of the alkenyl or the sp -hybridized carbon of the alkynyl is directly bonded, or the sp 2 -hybridized carbon of the alkenyl is directly bonded to It may be indirectly bonded through an sp ³ -hybridized carbon of an alkyl bonded to a 2 -hybridized carbon or an alkynyl sp ^- hybridized carbon.

A C _a -C _b functional group in this application means a functional group having a to b carbon atoms. For example, C _a -C _b alkyl refers to saturated aliphatic groups having a to b carbon atoms, including straight chain alkyls, branched chain alkyls, and the like. Straight chain or branched chain alkyl has 10 or less in its main chain (e.g. C ₁ -C ₁₀ straight chain, C ₃ -C ₁₀ branched chain), preferably 4 or less, more preferably 3 or less carbon atoms.

Specifically, alkyl includes methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl, t-butyl, pent-1-yl, pent-2-yl, pent- 3-yl, 3-methylbut-1-yl, 3-methylbut-2-yl, 2-methylbut-2-yl, 2,2,2-trimethyleth-1-yl, n-hexyl, n-heptyl, and It may also be n-oxytyl.

Aryl in this application, unless otherwise defined, means an unsaturated aromatic ring containing a single ring or multiple rings (preferably 1 to 4 rings) connected to each other by conjugations or covalent bonds. Non-limiting examples of aryl include phenyl, biphenyl, o-terphenyl, m-terphenyl, p-terphenyl, 1-naptyl, 2-naptyl, 1-anthryl, 2-anthryl. , 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, 9-phenanthrenyl, 1-pyrenyl, 2-pyrenyl, and 4-pyrenyl.

Heteroaryl in this application refers to a functional group in which one or more carbon atoms within the aryl defined above are replaced with a non-carbon atom such as nitrogen, oxygen or sulfur.

Non-limiting examples of heteroaryl include furyl, tetrahydrofuryl, pyrrolyl, pyrrolidinyl, thienyl, tetrahydrothienyl, oxazolyl, iso- xazolyl ( isoxazolyl, triazolyl, thiazolyl, isothiazolyl, pyrazolyl, pyrazolidinyl, oxadiazolyl iazolyl), thiadiazolyl, imidazolyl, imidazolinyl, pyridyl ( pyridyl), pyridaziyl, triazinyl, piperidinyl, morpholinyl, thiomorpholinyl, pyrazinyl , piperainyl, pyrimidinyl, naphthyridinyl, benzofuranyl, Benzothienyl, indolyl, indolinyl, indolizinyl, indazolyl, quinolidinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, pteridinyl ridinyl), quinuclidinyl, cabazoyl, acridinyl , phenazinyl, phenothizinyl, phenoxazinyl, furinyl, benzimidazolyl, benzothiazolyl, and their conjugated analogues.

Aralkyl in the present application is a functional group in which aryl is substituted on a carbon alkyl, and is a general term for -(CH ₂ ) _n Ar. Examples of aralkyl include benzyl (-CH ₂ C ₆ H ₅ ) or phenethyl (-CH ₂ CH ₂ C ₆ H ₅ ).

Cycloalkyl or heterocycloalkyl in this application, unless otherwise defined, may be understood as a cyclic structure of alkyl or heteroalkyl, respectively.

Non-limiting examples of cycloalkyl include cyclopentyl, cyclohexyl, 1-cyclohexenyl, 3-cyclohexenyl, cycloheptyl, and the like.

Non-limiting examples of cycloalkyl containing heteroatoms include 1-(1,2,5,6-tetrahydropyridyl), 1-piperidinyl, 2-piperidinyl, 3-piperidinyl, 4-morpholinyl, 3-morpholinyl, Examples include tetrahydrofuran-2-yl, tetrahydrofuran-3-yl, tetrahydrothien-2-yl, tetrahydrothien-3-yl, 1-piperazinyl, and 2-piperazinyl.

Further, cycloalkyl or cycloalkyl containing a hetero atom may have a form in which cycloalkyl, cycloalkyl containing a hetero atom, aryl or heteroaryl is joined or connected by a covalent bond.

The silicon additives described above are preferably present in the silicon substrate etching solution at 100 to 10,000 ppm.

If the silicon additive is present at less than 100 ppm in the silicon substrate etch solution, the amount of silane compounds decomposed and released from the silicon additive under the etching conditions will be too small, making the choice for silicon oxide versus silicon nitride films The effect of increasing the ratio is weak.

On the other hand, when the silicon additive in the silicon substrate etching solution exceeds 10,000 ppm, the amount of silane compounds decomposed and released from the silicon additive becomes too large under the etching conditions, resulting in not only a silicon oxide film but also a silicon oxide film. , a problem may arise in which the etching rate of the silicon nitride film decreases. Furthermore, the silane compound in the etching solution can itself act as a source of silicon-based particles.

A silicon substrate etching solution according to an embodiment of the present invention further includes a fluorine-containing compound to compensate for the silicon nitride etching rate reduced by using silicon additives and to improve the efficiency of the overall etching process. May contain.

Fluorine-containing compounds in this application refer to any compound in any form that dissociates fluorine ions.

In one embodiment, the fluorine-containing compound is at least one selected from hydrogen fluoride, ammonium fluoride, ammonium bifluoride, and ammonium hydrogen fluoride.

Furthermore, in another example, the fluorine-containing compound may be a compound in which an organic cation and a fluorine anion are ionically bonded.

For example, the fluorine-containing compound may be a compound in which an alkylammonium and a fluorine-based anion are ionically bonded. Here, alkylammonium is ammonium having at least one alkyl group, and may have up to four alkyl groups. The definition of the alkyl group is as described above.

In yet other examples, the fluorine-containing compound is alkylpyrrolium, alkylimidazolium, alkylpyrazolium, alkyloxazolium, alkylthiazolium, alkylpyridinium, alkylpyrimidinium, alkylpyridazinium, alkylpyrazolium, an organic cation selected from dinium, alkylpyrrolidinium, alkylphosphonium, alkylmophorinium, and alkylpiperidinium; and fluorophosphate, fluoroalkyl-fluorophosphate, fluoroborate, and fluoroalkyl-fluoroborate. The ionic liquid may be in the form of an ionic bond with a fluorine-based anion selected from lattice.

Compared to hydrogen fluoride or ammonium fluoride, which are commonly used as fluorine-containing compounds in silicon substrate etching solutions, fluorine-containing compounds provided in the form of ionic liquids have higher boiling points and decomposition temperatures; It has the advantage that there is little risk of changing the composition of the etching solution due to decomposition during the etching process.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device including an etching process performed using the silicon substrate etching solution described above.

According to this manufacturing method, a semiconductor element is manufactured by performing a selective etching process on a silicon nitride film using the above-mentioned etching solution on a silicon substrate containing at least a silicon nitride film (SI _x N _y ). is possible.

A silicon substrate used for manufacturing a semiconductor device may include a silicon nitride film, or may include both a silicon oxide film and a silicon nitride film. Further, in the case of a silicon substrate containing both a silicon oxide film and a silicon nitride film, the silicon oxide film and the silicon nitride film may be alternately stacked or stacked in different regions.

The method for manufacturing a semiconductor device according to the present invention provides a method for manufacturing a silicon nitride film without loss to a silicon oxide film in an element isolation process of a flash memory element, an element isolation process of a DELAM element, or a diode formation process of a phase change memory element. Process steps requiring selective removal may be performed using the silicon substrate etching solution described above.

Below, specific examples of the present invention will be shown. However, the examples described below are merely for specifically illustrating or explaining the present invention, and the present invention should not be limited thereby.

Composition of silicon substrate etching solution
Example 1
A silicon substrate etching solution was prepared by mixing 85% by weight of phosphoric acid, 1,000 ppm of a silicon additive represented by the following formula 5, and the remaining amount of water.

[C5]

Example 2
A silicon substrate etching solution was prepared in the same manner as in Example 1, except that 5,000 ppm of a silicon additive represented by the following chemical formula 6 was used.

[C6]

Example 3
A silicon substrate etching solution was produced in the same manner as in Example 1, except that a silicon additive represented by the following chemical formula 7 was used.

[C7]

Example 4
A silicon substrate etching solution was produced in the same manner as in Example 1, except that a silicon additive represented by the following chemical formula 8 was used.

[C8]

Example 5
A silicon substrate etching solution was prepared in the same manner as in Example 1, except that 90 ppm of silicon additive was used.

Example 6
A silicon substrate etching solution was prepared as in Example 2, except that 11,000 ppm of silicon additive was used.

Example 7
A silicon substrate etching solution was produced in the same manner as in Example 1, except that a silicon additive represented by the following chemical formula 9 was used.

[C9]

Comparative example 1
A silicon substrate etching solution was produced in the same manner as in Example 1, except that no silicon additive was used.

Comparative example 2
A silicon substrate etching solution was produced in the same manner as in Example 1, except that triethoxysilane was used as the silicon additive.

Comparative example 3
A silicon substrate etching solution was produced in the same manner as in Example 1, except that a silicon additive represented by the following chemical formula 10 was used.

[C10]

Experimental example 1
After heating the silicon substrate etching solution having the composition according to each example and comparative example to 165° C., a silicon oxide layer (thermal oxide layer) and a silicon nitride layer each having a thickness of 500 Å were immersed in the heated etching solution for 3 minutes. It was etched. At this time, the pH of the etching solution heated to 165° C. was measured to be within the range of 2.0 to 2.5.

The thickness of the silicon oxide film and silicon nitride film before and after etching was measured using ellipsometry (Nano-View, SE
MG-1000 (Ellipsometry) was used for measurement, and the measurement results are the average value of the results of 5 measurements. The etching rate is a value calculated by dividing the difference in thickness between the silicon oxide film and the silicon nitride film before and after etching by the etching time (3 minutes).

Further, after completing the etching, the etching solution was analyzed using a particle size analyzer to measure the average diameter of silicon-based particles present in the etching solution.

The measured etching rates and average diameters of silicon-based particles in the etching solution are shown in Table 1 below.

[Table 1]

Referring to the results in Table 1, compared to Comparative Example 1 in which no separate silicon additive is used, it is possible to increase the silicon concentration in the etching solution as a silicon additive, as in Comparative Example 2. When using a silane compound capable of forming a silicon oxide film, it is possible to lower the etching rate for a silicon oxide film and, as a result, improve the etching selectivity ratio for a silicon oxide film to a silicon nitride film. However, when a normal chain-shaped silane compound is used as a silicon additive as in Comparative Example 2, it can be confirmed that silicon-based particles have grown.

On the other hand, according to Examples 1 to 4, by using a cyclic silane compound, the silane compound (silic acid) is decomposed under the etching conditions. In this way, the etching rate of the silicon oxide film is lowered depending on the silicon concentration of the etching solution adjusted by the silane compound (silic acid) released into the etching solution with a delay, resulting in a difference between the silicon oxide film and the silicon nitride film. It can be confirmed that the etching selectivity to the film is improved.

Further, according to Examples 1 to 4, the silane compound (silic acid) is released into the etching solution in a delayed manner, so that the concentration of the silane compound (silic acid) in the etching solution increases too much. This can be prevented. As a result, it can be confirmed that, unlike Comparative Examples 2 and 3, silicon-based particles on the order of several micrometers do not grow.

On the other hand, the content of the silicon additive in the etching solution according to Example 5 was 90 ppm, and compared to Examples 1 to 4, the content of the silicon additive in the etching solution was relatively small. It can be confirmed that the effect of reducing the etching rate on the film is weak.

In addition, the content of silicon additive in the etching solution according to Example 6 was 11,000 ppm, which was too large compared to Examples 1 to 4. It can be confirmed that the silicon additive is deposited on the silicon oxide film, making it impossible to measure the etching rate of the silicon oxide film.

Although one embodiment of the present invention has been described above, a person having ordinary knowledge in the technical field will be able to add or add constituent elements without departing from the spirit of the present invention as described in the claims. The present invention can be modified and modified in various ways through changes, deletions, additions, etc., and these are also within the scope of the rights of the present invention.

Claims (7)

A silicon substrate etching solution for etching a silicon nitride film,
an inorganic acid aqueous solution; and
A silicone additive represented by the following chemical formula 1;
including,
Silicon substrate etching solution:
[Chemical formula 1]
here,
Z is represented by the following chemical formula 2,
[Chemical 2]
X ₁ and X ₂ are each independently oxygen or sulfur,
R ₁ to R ₄ are each independently hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heteroalkyl containing at least one heteroatom, C ₂ -C ₁₀ alkenyl, C ₂ - _C10 alkynyl, C1 _{- C10} haloalkyl _, C1- _C10 aminoalkyl, aryl, heteroaryl, aralkyl and hydroxy, amino, halogen, sulfone, phosphonic, phosphoric, thiol, alkoxy, amide, ester, selected from acid anhydrides, acyl halides, cyanos, carboxyls and azoles, and Y ₁ to Y ₄ are each independently hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, at least one heteroatom Including C ₂ -C ₁₀ heteroalkyl, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, aralkyl and hydroxy, amino, halogen , sulfone, phosphonic, phosphoric, thiol, alkoxy, amide, ester, acid anhydride, acyl halide, cyano, carboxyl and azole, and n is a constant between 1 and 5. The inorganic acid aqueous solution is an aqueous solution containing at least one inorganic acid selected from sulfuric acid, nitric acid, phosphoric acid, silicic acid, hydrofluoric acid, boric acid, hydrochloric acid, perchloric acid, phosphoric anhydride, pyrophosphoric acid, and polyphosphoric acid. is,
The silicon substrate etching solution according to claim 1. The silicon additive is included in the silicon substrate etching solution in an amount of 100 to 10,000 ppm.
The silicon substrate etching solution according to claim 1. 2. The silicon substrate etching solution according to claim 1, wherein the silicon substrate etching solution etches a single film made of a silicon nitride film or a multilayer film including both a silicon oxide film and a silicon nitride film. The silicon substrate etching solution further includes at least one fluorine-containing compound selected from hydrogen fluoride, ammonium fluoride, ammonium bifluoride, and ammonium hydrogen fluoride.
The silicon substrate etching solution according to claim 1. The silicon substrate etching solution further includes a fluorine-containing compound in which an organic cation and a fluorine anion are ionically bonded.
The silicon substrate etching solution according to claim 1. A method for manufacturing a semiconductor device, comprising an etching step performed using a silicon substrate etching solution according to any one of claims 1 to 6.