KR20170134899A - Etching solution for silicon nitride layer - Google Patents

Abstract

The present invention relates to an etching solution for a silicon nitride film, which can prevent an etching rate of a silicon oxide film from being increased by fluorine ions released in excess in the etching solution for a silicon nitride film and suppress the generation of silicon-based particles.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a silicon nitride (SiN)

TECHNICAL FIELD The present invention relates to a silicon nitride film etching solution, and more particularly, to a silicon nitride film etching solution capable of suppressing the generation of silicon-based particles upon etching a silicon nitride film.

There are various methods of etching the silicon nitride film and the silicon oxide film at present, but dry etching and wet etching are mainly used.

The dry etching method is usually a gas etching method, but isotropic is superior to the wet etching method. However, the wet etching method is widely used because the productivity is much lower than the wet etching method and the method is expensive.

In general, a wet etching method using phosphoric acid as an etching solution is well known, and etching of a silicon nitride film by phosphoric acid proceeds through the following chemical reaction.

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

When only pure phosphoric acid is used for etching the silicon nitride film, problems such as various defects and pattern abnormalities may occur due to the etching of not only the silicon nitride film but also the silicon oxide film due to miniaturization of the device, so that the etching rate of the silicon oxide film is further lowered There is a need.

Recently, silicon additives have been used together with phosphoric acid in order to increase the etching rate of the silicon nitride film and lower the etching rate of the silicon oxide film.

However, since the silane compound mainly used as a silicon additive is basically low in solubility in an etching solution containing phosphoric acid, a hydrophilic functional group (for example, a hydroxyl group ) Are combined with each other.

When a silane compound in which a hydrophilic functional group is bonded to a silicon atom is used as a silicon additive, the appropriate solubility of the silane compound in the etching solution can be secured, but some problems arise.

First, if the concentration of the silane compound in the etching solution is increased to increase the selectivity to the silicon nitride film for the silicon oxide film, the etching rate of the silicon nitride film may be lowered depending on the increased silicon concentration in the etching solution .

That is, when the silicon additive is used, the etching rate is controlled according to the principle of chemical equilibrium in Le Chatelier by increasing the concentration of silicon in the etching solution. However, when the concentration of silicon is increased to an appropriate level or higher, In addition, the etching rate for the silicon nitride film is lowered and the productivity is lowered.

Secondly, the use of a silane compound as a silicon additive can result in an increased silicon concentration in the etch solution acting as the source (nucleus or seed) of the silicon-based particles, and the silicon-based particles generated during etching or post- Which is the largest cause of defects.

For example, various hydrophilic functional groups bonded to silicon atoms may be substituted with hydroxy groups during etching or cleaning with H ₂ O to form a silicone-hydroxyl group (-Si-OH), and the silicon-hydroxy groups (-Si-O-Si-) group which forms a random chain structure by alternately bonding silicon atoms and oxygen atoms by polymerization.

Silane compounds containing siloxane groups result in the growth and precipitation of the siloxane groups as repeatedly polymerized silicon-based particles, and the silicon-based particles remain on the silicon substrate, causing defects in devices implemented on the substrate, (E. G., A filter) and cause equipment failure.

Therefore, there is an urgent need to develop a silicon nitride film etching solution capable of suppressing the generation of silicon-based particles during etching or cleaning after etching.

An object of the present invention is to provide a silicon nitride film etching solution capable of increasing a selectivity to a silicon nitride film compared to a silicon oxide film by using a silane compound-based silicon additive.

It is another object of the present invention to provide a silicon nitride film etching solution capable of compensating for an etching rate lowered by use of a silicon additive as a fluorine-containing compound is used.

It is another object of the present invention to provide a fluorine-containing fluorine-containing fluorine-containing fluorine-containing fluorine-containing fluorine-containing fluorine-containing fluorine-containing fluorine- And a silicon nitride film etching solution in which a compounding ratio is determined.

Another object of the present invention is to provide a silicon nitride film etching solution capable of suppressing the generation of silicon-based particles by further including a heterogeneous silane compound having a different number of hydrophilic functional groups bonded to silicon atoms.

In addition, the present invention further includes a silane compound having a different number of hydrophilic functional groups bonded to silicon atoms, thereby preventing an increase in the etching rate of the silicon oxide film due to excess fluorine ions present in the etching solution, Which is capable of suppressing the formation of a silicon nitride film.

In order to solve the above-mentioned technical problems, the silicon nitride film etching solution according to an aspect of the present invention includes an inorganic acid aqueous solution, at least one silicon atom containing one to six silicon atoms and three or more hydrophilic functional groups bonded thereto A first silane compound and a fluorine-containing compound.

Here, the first silane compound and the fluorine-containing compound are preferably present in an amount satisfying the following formula (1).

[Formula 1]

? = number of hydrophilic functional groups bonded to the silicon atom of the first silane compound

? '(molecular weight of the first silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the first silane compound)

alpha "= molecular weight of the hydroxyl group

Tα = content (g) of the first silane compound in the silicon nitride film etching solution

? = number of fluorine free from fluorine-containing compounds

? '= (molecular weight of fluorine-containing compound) - (sum of atomic amounts of all fluorine contained in fluorine-containing compound)

β "= atomic weight of fluorine

T? = Content of fluorine-containing compound in silicon nitride film etching solution (g)

As the first silane compound and the fluorine-containing compound exist in a content satisfying the above-mentioned formula 1, a silicon nitride film etching solution capable of suppressing the generation of silicon-based particles from the silicon additive can be provided. In addition, since the first silane compound and the fluorine-containing compound are present in the content satisfying the above-mentioned formula 1, the etching rate for the silicon oxide film is prevented from being rapidly increased by the fluorine ions liberated from the fluorine- It is possible to provide a silicon nitride film etching solution capable of reducing the selectivity ratio to the silicon nitride film compared to the oxide film.

The silicon nitride film etching solution according to another aspect of the present invention includes an inorganic acid aqueous solution and one to six silicon atoms, A first silane compound containing at least one silicon atom bonded with three or more hydrophilic functional groups, a second silane compound containing one to six silicon atoms and having a maximum of two hydrophilic functional groups bonded to one silicon atom, Fluorine-containing compounds.

Here, the first silane compound, the second silane compound, and the fluorine-containing compound are preferably present in an amount satisfying Formula 2 below.

[Formula 2]

? = number of hydrophilic functional groups bonded to the silicon atom of the first silane compound

? '(molecular weight of the first silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the first silane compound)

Tα = content (g) of the first silane compound in the silicon nitride film etching solution

? = number of fluorine free from fluorine-containing compounds

? '= (molecular weight of fluorine-containing compound) - (sum of atomic amounts of all fluorine contained in fluorine-containing compound)

T? = Content of fluorine-containing compound in silicon nitride film etching solution (g)

? = number of hydrophilic functional groups bonded to the silicon atom of the second silane compound

? '= (molecular weight of the second silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the second silane compound)

? "= molecular weight of the hydroxyl group

T? = Content of the second silane compound in the silicon nitride film etching solution (g)

The presence of the first silane compound, the second silane compound and the fluorine-containing compound in the content satisfying the above-mentioned formula 2 prevents the etching rate of the silicon oxide film from being increased by the excessive fluorine ions, It is possible to provide a silicon nitride film etching solution capable of compensating an etching rate which is lowered in accordance with use and improving a selectivity to a silicon nitride film compared to a silicon oxide film.

The silicon nitride film etching solution according to the present invention can increase the selectivity to the silicon nitride film compared to the silicon oxide film by using the silane compound-based silicon additive.

In addition, the fluorine-containing compound is further contained in an amount satisfying Formula 1 or Formula 2 to prevent the silicon oxide film from being etched by fluorine ions excessively liberated in the etching solution, There is an advantage that it is possible to compensate the etching rate.

In addition, since the silicon nitride film etching solution according to the present invention uses a heterogeneous silane compound having a different number of hydrophilic functional groups bonded to silicon atoms, the etching rate of the silicon oxide film is prevented from increasing due to the fluorine ions excessively liberated in the etching solution It is possible to effectively suppress generation of silicon-based particles during etching or cleaning after etching.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described hereinafter. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Hereinafter, the silicon nitride film etching solution according to the present invention will be described in detail.

A silicon nitride film etching solution according to an aspect of the present invention includes an inorganic acid aqueous solution, a first silane compound containing 1 to 6 silicon atoms and containing at least one silicon atom bonded with three or more hydrophilic functional groups, and a fluorine-containing compound . ≪ / RTI >

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 be used.

The inorganic acid aqueous solution is a component that suppresses the generation of nanometer-scale silicon-based particles while maintaining the pH of the etching solution, thereby inhibiting various types of silane compounds present in the etching solution from changing to silicon-based particles.

In one embodiment, the inorganic acid aqueous solution is preferably contained in an amount of 60 to 90 parts by weight based on 100 parts by weight of the silicon nitride film etching solution.

When 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 nitride film etching solution, the etching rate of the silicon nitride film is lowered and the silicon nitride film is not sufficiently etched or the process efficiency of etching the silicon nitride film is lowered.

On the other hand, when the content of the inorganic acid aqueous solution exceeds 90 parts by weight with respect to 100 parts by weight of the silicon nitride film etching solution, not only the etching rate of the silicon nitride film is excessively increased but also the silicon nitride film The selectivity may be lowered, and the silicon substrate may be defective due to the etching of the silicon oxide film.

The silicon nitride film etching solution according to an embodiment of the present invention includes a first silane compound represented by the following Chemical Formula 1 or Chemical Formula 2 in order to increase the selectivity for the silicon nitride film versus the silicon oxide film.

As indicated by the following formula (1), the first silane compound may be defined as a compound in which the functional group of R ₁ to R ₄ is bonded to one silicon atom. Here, at least three of R ₁ to R ₄ are hydrophilic functional groups.

[Chemical Formula 1]

Wherein each of R ₁ to R ₄ is independently a hydrophilic functional group or is selected from the group consisting of 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 -C ₁₀ alkynyl is, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, functional group selected from aryl, heteroaryl, aralkyl, aryloxy and silyl siloxanes.

Further, as indicated by the following formula (2), the first silane compound may be defined herein as a silane compound in which at least two silicon atoms are continuously bonded.

(2)

Wherein each of R ₅ to R ₁₀ is independently a hydrophilic functional group or is selected from the group consisting of 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 -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, aralkyl and functional groups selected from alkyl, silyloxy and siloxane, n is 1 < / RTI >

That is, the first silane compound contains 1 to 6 silicon atoms, and includes at least one silicon atom bonded with three or more hydrophilic functional groups, thereby ensuring sufficient solubility in a silicon nitride film etching solution containing an inorganic acid aqueous solution It is possible.

Also, it is possible for the first silane compound to form relatively strong hydrophilic interactions with the silicon substrate, especially the silicon oxide film, as it comprises at least one silicon atom bonded with three or more hydrophilic functional groups.

The first silane compound attached to the surface of the silicon oxide film through strong hydrophilic interaction can prevent the silicon oxide film from being etched from the inorganic acid or the fluorine-containing compound of the silicon oxide film.

The hydrophilic functional group bonded to the silicon atom means a functional group which can be substituted with a hydroxyl group under a pH condition of a hydroxyl group or an inorganic acid aqueous solution.

Examples of the functional group that can be substituted with a hydroxyl group under the pH condition of the inorganic acid aqueous solution include an amino group, a halogen group, a sulfonic group, a phosphonic group, a phosphoric group, a thiol group, an alkoxy group, an amide group, An acyl halide group, a cyano group, a carboxyl group, and an azole group, and is not necessarily limited to the above-mentioned functional groups, but should be understood to include any functional group capable of substituting with a hydroxy group under pH conditions of an aqueous solution of an inorganic acid.

The pH condition of the inorganic acid aqueous solution herein means 4 or less. When the pH condition of the inorganic acid aqueous solution is more than 4, the stability of the first silane compound present in the silicon nitride film etching solution is lowered due to the relatively high pH, and there is a fear that it acts as the source of the silicon based particle.

Halogen in the present context means fluoro (-F), chloro (-Cl), bromo (-Br) or iodo (-I), and haloalkyl means alkyl substituted with halogen as described above. For example, halomethyl means methyl (-CH ₂ X, -CHX ₂ or -CX ₃ ) in which at least one of the hydrogens of methyl is replaced by halogen.

In addition, alkoxy in the context of the present invention means both an -O- (alkyl) group and an -O- (unsubstituted cycloalkyl) group, and is a straight chain or branched hydrocarbon having at least one ether group and from 1 to 10 carbon atoms.

Specific examples include methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n- But are not limited to, cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, and the like.

R _a when an alkenyl or alkynyl imidazol (where, a is an integer selected from 1 to 4), sp ² of alkenyl-alkenyl of an sp- mixed carbon of the hybrid carbon or alkynyl group bonded directly or Al sp ² - of the alkyl bonded to the carbon of a hybrid mixed sp- or alkynyl carbon sp ³ - it may be indirectly coupled by a hybrid form of carbon.

The C _a -C _b functional group herein means a functional group having a to b carbon atoms. For example, C _a -C _b alkyl means a saturated aliphatic group, including straight chain alkyl and branched alkyl, having a to b carbon atoms, and the like. The straight chain or branched chain alkyl has 10 or fewer (for example, a straight chain of C ₁ -C ₁₀ , C ₃ -C ₁₀ ), preferably 4 or less, more preferably 3 or less carbon atoms .

Specifically, the alkyl is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl, t-butyl, pent- Methylbut-2-yl, 2,2,2-trimethylet-1-yl, n-hexyl, n-heptyl and n - octyl.

Aryl herein, unless otherwise defined, means an unsaturated aromatic ring comprising a single ring or multiple rings (preferably one to four rings) joined together or covalently bonded to each other. Non-limiting examples of aryl include phenyl, biphenyl, terphenyl, m-terphenyl, p-terphenyl, 1-naphthyl, 2- naphthyl, Anthryl, 9-anthryl, phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, 9-phenanthrenyl, Pyrenyl and 4-pyrenyl.

As used herein, heteroaryl means a functional group in which at least one carbon atom in the aryl as defined above is replaced by a non-carbon atom such as nitrogen, oxygen or sulfur.

Non-limiting examples of heteroaryl include furyl, tetrahydrofuryl, pyrrolyl, pyrrolidinyl, thienyl, tetrahydrothienyl, oxazolyl, , Isoxazolyl, triazolyl, thiazolyl, isothiazolyl, pyrazolyl, pyrazolidinyl, oxadiazolyl, thiadiazolyl, thiadiazolyl, a thiadiazolyl group, an imidazolyl group, an imidazolinyl group, a pyridyl group, a pyridaziyl group, a triazinyl group, a piperidinyl group, a morpholinyl group, Thiomorpholinyl, pyrazinyl, piperainyl, pyrimidinyl, naphthyridinyl, benzofuranyl, benzothienyl, indolyl, and the like. , Indolinyl, indolizinyl, indazolyl, quinolizinyl, quinolinyl, iso Quinolinyl, quinolinyl, quinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, pteridinyl, quinuclidinyl, carbazoyl, acridinyl, Phenothiazinyl, phenothizinyl, phenoxazinyl, purinyl, benzimidazolyl, benzothiazolyl, and the like.

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

A cycloalkyl or a heterocycloalkyl containing a heteroatom herein may be understood as a cyclic structure of alkyl or heteroalkyl, respectively, unless otherwise defined.

Non-limiting examples of hydrocarbon rings include cyclopentyl, cyclohexyl, 1-cyclohexenyl, 3-cyclohexenyl, and cycloheptyl.

Non-limiting examples of hydrocarbon rings containing heteroatoms include 1- (1,2,5,6-tetrahydropyridyl), 1-piperidinyl, 2-piperidinyl, 3-piperidinyl, 4- Tetrahydrofuran-2-yl, tetrahydrothien-3-yl, 1-piperazinyl and 2-piperazinyl, - piperazinyl, and the like.

A hydrocarbon ring containing a hydrocarbon ring or a hetero atom may also have a hydrocarbon ring, a hydrocarbon ring containing a hetero atom, an aryl or a heteroaryl, or a covalent bond.

Silyloxy is a generic term for -O-Si (R) ₃ in which the silyl is replaced by oxygen.

It is preferable that the first silane compound is present at 100 to 10,000 ppm in the silicon nitride film etching solution.

When the first silane compound in the silicon nitride film etching solution is present at less than 100 ppm, the effect of increasing the selectivity to the silicon nitride film compared to the silicon oxide film may be insufficient. On the other hand, if the first silane compound in the silicon nitride film etching solution exceeds 10,000 ppm, the etching rate of the silicon nitride film may be lowered depending on the increased silicon concentration in the silicon nitride film etching solution. It can act as a source of particles.

The silicon nitride film etching solution according to an embodiment of the present invention may include a fluorine-containing compound to compensate for the etching rate of the silicon nitride film which is lowered due to the inclusion of the first silane compound as a silicon additive, .

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

Further, in another embodiment, the fluorine-containing compound may be a compound in which the organic cations and the fluorine anions are ionically bonded.

For example, the fluorine-containing compound may be a compound in which the alkylammonium and the 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 has been described above.

In another example, the fluorine-containing compound is selected from the group consisting of alkylpyrrolidium, alkylimidazolium, alkylpyrazolium, alkyloxazolium, alkylthiazolium, alkylpyridinium, alkylpyrimidinium, alkylpyridazinium, Fluoroalkyl-fluoroalkyl, fluoroalkyl-fluoroalkyl, fluoroalkyl-fluoroalkyl, fluoroalkyl-fluoroalkyl, fluoroalkyl-fluoroalkyl, fluoroalkyl-fluoroalkyl, fluoroalkyl-fluoroalkyl and fluoroalkyl-fluoroalkyl And the fluorine-based anion selected from fluoroborate may be an ionic liquid in the ion-bonded form.

The fluorine-containing compound provided in the form of an ionic liquid as compared with hydrogen fluoride or ammonium fluoride generally used as a fluorine-containing compound in a silicon nitride etching solution has a high boiling point and a decomposition temperature and is decomposed in an etching process performed at a high temperature There is an advantage that the composition of the etching solution is less likely to change.

Accordingly, the silicon nitride film etching solution according to the present invention is characterized in that the first silane compound and the fluorine-containing compound satisfy the following formula 1 in consideration of the characteristics of the first silane compound and the fluorine-containing compound do.

[Formula 1]

? = number of hydrophilic functional groups bonded to the silicon atom of the first silane compound

? '(molecular weight of the first silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the first silane compound)

alpha "= molecular weight of the hydroxyl group

Tα = content (g) of the first silane compound in the silicon nitride film etching solution

? = number of fluorine free from fluorine-containing compounds

? '= (molecular weight of fluorine-containing compound) - (sum of atomic amounts of all fluorine contained in fluorine-containing compound)

β "= atomic weight of fluorine

T? = Content of fluorine-containing compound in silicon nitride film etching solution (g)

The first silane compound in the silicon nitride etch solution serves to increase the selectivity to the silicon nitride film versus the silicon oxide film, but decreases the overall etch rate by increasing the total concentration of silicon present in the solution in the silicon nitride etch solution during etching There is a disadvantage.

Accordingly, the silicon nitride film etching solution according to the present invention compensates for the etching rate which is lowered by the use of the first silane compound by further containing the fluorine-containing compound. However, when the fluorine ions liberated from the fluorine- If the excess amount of the etching solution is present in the nitride etching solution, the etch rate of the silicon oxide film can be increased to lower the etching selectivity to the silicon nitride film compared to the silicon oxide film.

Accordingly, the number of hydrophilic functional groups bonded to the silicon atom of the first silane compound, the hydroxyl group, wherein the hydroxy group is a hydroxyl group initially bonded to the first silane compound or Means all of the hydroxyl groups substituted from the hydrophilic functional group under the pH condition of the inorganic acid aqueous solution), the sum of the molecular weight of the first silane compound in the silicon nitride film etching solution and the number of fluorine in the fluorine-containing compound, It is preferable to determine the content of the first silane compound and the fluorine-containing compound in the silicon nitride film etching solution in consideration of the sum of the atomic amounts of all fluorine contained and the content of the fluorine-containing compound in the silicon nitride film etching solution.

Here, when the inequality of Formula 1 is not established (i.e., when the left side of the inequality is large), the content of the first silane compound in the etching solution is excessively large, so that the silicon based particles in the etching solution are spontaneously generated have. In addition, there is a high possibility that silicon-based particles are present on the silicon substrate after etching.

Further, when the value of Tβ is excessively large in the formula (1), as the etching rate of the silicon oxide film is drastically increased by the excess fluorine dissociated from the fluorine-containing compound, the selectivity to the silicon nitride film may decrease.

Further, even if the inequality of the formula 1 is established, in order to prevent the etching rate of the silicon oxide film from increasing as the degree of the fluorine content increases from the fluorine-containing compound under various conditions such as the etching temperature and the pH of the silicon nitride film etching solution The silicon nitride film etching solution according to the present invention may further comprise a second silane compound containing 1 to 6 silicon atoms and having a maximum of two hydrophilic functional groups bonded to one silicon atom.

Thus, according to the present invention, the second silane compound represented by the following general formula (3) or (4) is further included in the silicon nitride film etching solution to increase the etch rate of the silicon oxide film caused by the fluorine ions liberated from the fluorine- It is possible to suppress the problem.

As indicated by the following formula (3), the second silane compound can be defined as a compound in which the functional group of R ₁₁ to R ₁₄ is bonded to one silicon atom. Here, among R ₁₁ to R ₁₄ , there are one or two hydrophilic functional groups.

(3)

Wherein each of R ₁₁ to R ₁₄ is independently a hydrophilic functional group or is selected from the group consisting of 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 -C ₁₀ alkynyl is, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, functional group selected from aryl, heteroaryl, aralkyl, aryloxy and silyl siloxanes.

Further, as indicated by the following chemical formula (4), the second silane compound may be defined herein as a silane compound in which at least two silicon atoms are continuously bonded.

[Chemical Formula 4]

Wherein R ₁₅ to R ₂₀ are each independently a hydrophilic functional group or is selected from the group consisting of 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 -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, aralkyl and functional groups selected from alkyl, silyloxy and siloxane, n is 1 < / RTI >

That is, the second silane compound includes 1 to 6 silicon atoms, and includes a hydrophilic functional group bonded to a silicon atom, thereby securing an appropriate level of solubility in a silicon nitride film etching solution containing an inorganic acid aqueous solution .

Accordingly, the second silane compound, which is properly dissolved in the silicon nitride film etching solution, reacts with the fluorine-containing compound existing in an excessive amount relative to the first silane compound, thereby preventing the etching rate of the silicon oxide film from increasing.

In addition, since the second silane compound has a smaller number of hydrophilic functional groups than the first silane compound, the possibility that the second silane compound acts as the nucleus of the silicon-based particles can be minimized.

In particular, the second silane compound may have up to two silicon-hydroxyl groups (-Si-OH) under the pH conditions of an aqueous inorganic acid solution, as it has at most two hydrophilic functional groups for ensuring solubility in the silicon nitride etching solution.

Here, the meaning of the second silane compound having at most two hydrophilic functional groups means that the number of hydrophilic functional groups bonded to one silicon atom is at most two. It is also preferable that the second silane compound has at least one hydrophilic functional group in order to ensure solubility in the silicon nitride film etching solution.

Therefore, when the number of silicon atoms constituting the second silane compound is one, it is preferable that one or two hydrophilic functional groups among the four functional groups bonded to the silicon atom are present. In addition, when the number of silicon atoms constituting the second silane compound is two or more, it is preferable that at least one silicon atom is bonded to at least two hydrophilic functional groups.

At this time, when the hydrophilic functional group in the second silane compound is substituted with the silicon-hydroxyl group (-Si-OH) under the pH condition of the inorganic acid aqueous solution, the second silane compound has a silicon-hydroxyl group (-Si-OH) Silicon oligomer or silicone oil having a regular one-dimensional or two-dimensional arrangement is obtained by polymerization with the first silane compound or the second silane compound, and it is believed that silicon-based particles are generated by random growth Can be prevented.

At this time, the silicon nitride film etching solution according to the present invention is the first silane compound in consideration of the characteristics of the first silane compound, the second silane compound and the fluorine-containing compound. The second silane compound and the fluorine-containing compound are contained in an amount satisfying the following formula (2).

[Formula 2]

? = number of hydrophilic functional groups bonded to the silicon atom of the first silane compound

? '(molecular weight of the first silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the first silane compound)

Tα = content (g) of the first silane compound in the silicon nitride film etching solution

? = number of fluorine free from fluorine-containing compounds

? '= (molecular weight of fluorine-containing compound) - (sum of atomic amounts of all fluorine contained in fluorine-containing compound)

T? = Content of fluorine-containing compound in silicon nitride film etching solution (g)

? = number of hydrophilic functional groups bonded to the silicon atom of the second silane compound

? '= (molecular weight of the second silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the second silane compound)

? "= molecular weight of the hydroxyl group

T? = Content of the second silane compound in the silicon nitride film etching solution (g)

The presence of the first silane compound, the second silane compound and the fluorine-containing compound in the content satisfying the above-mentioned formula 2 prevents the etching rate of the silicon oxide film from being increased by the excessive fluorine ions, It is possible to compensate the etching rate which is lowered depending on the use and to improve the selectivity to the silicon nitride film compared to the silicon oxide film.

In addition, by replacing the hydroxy group of the silicon-based particles during the etching or the cleaning after the etching with siloxane groups that can not be further polymerized, it is possible to prevent the silicon-based particles having a size of several nanometers from growing and precipitating in micrometer size.

As described above, the silicon nitride film etching solution according to the present invention maintains a high etching rate for the silicon nitride film and a high selectivity to the silicon nitride film compared to the silicon oxide film, and controls generation of silicon-based particles during etching or cleaning after etching There is an advantage to be able to do.

Accordingly, when the silicon substrate including the silicon nitride film and the silicon oxide film is etched at 165 ° C. for 3 minutes with the silicon nitride film etching solution according to the present invention, the average diameter of the silicon-based particles generated may be 0.1 μm or less.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

Experimental Example  One

A first silane compound and a fluorine-containing compound (HF) were compounded in 750 g of 85% phosphoric acid aqueous solution in the contents shown in Table 1 below to prepare an etching solution.

division The first silane compound
(ppm) Fluorine-containing compound
(ppm) Left side Right side Satisfying the inequality of Eq. 1 Comparative Example 1 500 100 7.5 1.8 dissatisfaction Comparative Example 2 300 7.5 5.4 dissatisfaction Example 1 420 7.5 7.6 satisfied Example 2 460 7.5 8.3 satisfied Example 3 500 7.5 9.0 satisfied

를 의미하며,Here, the term " left side "

&Quot;

를 의미한다.Right side

.

For example, the left side and the right side of the etching solution according to Example 1 were calculated based on the contents shown in Tables 2 and 3, respectively.

85% phosphoric acid
Based on 750g Molecular Weight alpha α ' α " Tα Silicic acid 96 4 28 17 0.375

85% phosphoric acid
Based on 750g Molecular Weight beta β ' β " T? HF 20 One One 19 0.315

After the etching solution was heated to 165 ° C, a silicon oxide layer (ALD oxide layer) was etched for 3 minutes. The thickness of the silicon oxide layer before and after etching was measured using a Nano-View (SE MG-1000; Ellipsometry). The measurement result is an average value of five measurements. The etching rate is a value calculated by dividing the thickness difference of the silicon oxide film before and after the etching by the etching time (3 minutes).

After completion of the etching, the etching solution was analyzed by a particle size analyzer to measure the average diameter of the silicon particles present in the etching solution.

The measured etch rate and the average diameter of the silicon-based particles in the etching solution are shown in Table 4 below.

division Silicone-based particles
Average diameter (μm) 열 산화물 층
Etching speed (Å / min) ALD oxide layer
Etching speed (Å / min) Comparative Example 1 117 0.2 7.3 Comparative Example 2 70 1.3 15.6 Example 1 <0.01 1.9 18.3 Example 2 <0.01 2.2 21.2 Example 3 <0.01 2.5 26.4

As shown in Table 4, when the content of the first silane compound and the fluorine-containing compound in the etching solution did not satisfy the formula 1, it was confirmed that the silicon-based particles having an average diameter of several tens of micrometers or more were grown in the etching solution after etching have.

In addition, the etching rate of the silicon oxide film can be lowered by etching the first silane compound and the fluorine-containing compound in the etching solution so as to satisfy the formula (1).

Experimental Example  2

The first silane compound (3-aminopropylsilanetriol) and the fluorine-containing compound (NH ₄ F) were compounded in 750 g of 85% phosphoric acid aqueous solution in the contents shown in the following Table 5 to prepare an etching solution.

division The first silane compound
(ppm) Fluorine-containing compound
(ppm) Left side Right side Satisfying the inequality of Eq. 1 Comparative Example 3 1000 300 27.7 10.3 dissatisfaction Comparative Example 4 500 27.7 17.2 dissatisfaction Example 4 810 27.7 27.8 satisfied Example 5 850 27.7 29.2 satisfied Example 6 970 27.7 33.3 satisfied

Here, the definition of the left side and the right side and the calculation method thereof are the same as those of Experimental Example 1. [

Using the etching solution described in Table 5, the etching rate for the silicon oxide layer (thermal oxide layer and ALD oxide layer) and the average diameter of the silicon-based particles in the etching solution were measured in the same manner as in Experimental Example 1, 6.

division Silicone-based particles
Average diameter (μm) 열 산화물 층
Etching speed (Å / min) ALD oxide layer
Etching speed (Å / min) Comparative Example 3 137 0.4 4.2 Comparative Example 4 88 0.9 8.6 Example 4 <0.01 1.8 17.6 Example 5 <0.01 2.0 18.7 Example 6 <0.01 2.5 20.5

As shown in Table 6, when the content of the first silane compound and the fluorine-containing compound in the etching solution did not satisfy the formula 1, it was confirmed that the silicon-based particles having an average diameter of several tens of micrometers or more were grown in the etching solution after etching have.

Experimental Example  3

A first silane compound, a second silane compound (trimethylsilanol) and a fluorine-containing compound (NH ₄ F) were compounded in 750 g of 85% phosphoric acid aqueous solution in the contents shown in Table 7 below to prepare an etching solution.

division The first silane compound
(ppm) The second silane compound
(ppm) Fluorine-containing compound
(ppm) Left side Right side 1 Right side 2 Satisfying the inequality in Equation 2 Comparative Example 5 500 300 500 1252 812 200 dissatisfaction Comparative Example 6 500 1252 812 333 dissatisfaction Comparative Example 7 300 1252 487 333 dissatisfaction Example 7 1000 500 1252 812 667 satisfied Example 8 1000 1000 1252 1625 667 satisfied Example 9 1000 1500 1252 2438 667 satisfied

를 의미하며,Here, the left-

&Quot;

를 의미하며,Right side 1 is the right side of equation

&Quot;

를 의미한다.Right side 2 is the right side of Equation 2

.

Using the etching solution described in Table 7, the etching rate for the silicon oxide layer (thermal oxide layer and ALD oxide layer) and the average diameter of the silicon-based particles in the etching solution were measured in the same manner as in Experimental Example 1, 8 &lt; / RTI &gt;

division Silicone-based particles
Average diameter (μm) 열 산화물 층
Etching speed (Å / min) ALD oxide layer
Etching speed (Å / min) Comparative Example 5 114 1.1 13.5 Comparative Example 6 89 0.6 5.8 Comparative Example 7 146 0.4 3.9 Example 7 <0.01 1.6 11.3 Example 8 <0.01 1.7 15.5 Example 9 <0.01 1.7 14.2

As shown in Table 8, when the content of the first silane compound, the second silane compound and the fluorine-containing compound in the etching solution does not satisfy the formula 2, the silicon-based particles having an average diameter of several tens of micrometers or more in the etching solution after etching, Of the total.

Further, in Experimental Example 3, the use of the second silane compound within the content range satisfying Formula 2 shows that the etching rate for the silicon oxide film is decreased compared to Experimental Examples 1 and 2 in which the second silane compound is not used .

Experimental Example  4

(3-aminopropylsilanetriol), a second silane compound (dichlorodimethylsilane) and a fluorine-containing compound (NH ₄ F) were added to 750 g of an aqueous 85% phosphoric acid solution in an amount shown in Table 9 below to prepare an etching solution.

division The first silane compound
(ppm) The second silane compound
(ppm) Fluorine-containing compound
(ppm) Left side Right side 1 Right side 2 Satisfying the inequality in Equation 2 Comparative Example 8 500 200 100 896 221 254 dissatisfaction Comparative Example 9 300 200 896 442 381 dissatisfaction Example 10 500 500 896 1106 635 satisfied Example 11 1000 700 896 1549 1270 satisfied Example 12 2000 1000 896 2213 2540 satisfied

Here, definitions of the left side, right side 1 and right side 2, and calculation methods thereof are the same as those of Experimental Example 3.

Using the etching solution described in Table 9, the etching rate for the silicon oxide layer (thermal oxide layer and ALD oxide layer) and the average diameter of the silicon-based particles in the etching solution were measured in the same manner as in Experimental Example 1, 10.

division Silicone-based particles
Average diameter (μm) 열 산화물 층
Etching speed (Å / min) ALD oxide layer
Etching speed (Å / min) Comparative Example 8 79 0.3 3.6 Comparative Example 9 64 0.5 4.3 Example 10 <0.01 1.7 12.8 Example 11 <0.01 1.8 13.3 Example 12 <0.01 1.8 12.1

As shown in Table 10, when the content of the first silane compound, the second silane compound and the fluorine-containing compound in the etching solution does not satisfy the formula 2, the silicon-based particles having an average diameter of several tens of micrometers or more in the etching solution after etching Of the total.

Further, in Experimental Example 4, the use of the second silane compound within the content range satisfying Formula 2 shows that the etching rate for the silicon oxide film is reduced compared to Experimental Examples 1 and 2 in which the second silane compound is not used .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention as set forth in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

Claims (13)

Inorganic acid aqueous solution;
A first silane compound comprising from 1 to 6 silicon atoms and comprising at least one silicon atom bonded to at least three hydrophilic functionalities; And
Fluorine-containing compound,
Wherein the first silane compound and the fluorine-containing compound are present in an amount satisfying the following formula 1:
Silicon nitride film etching solution:
[Formula 1]

? = number of hydrophilic functional groups bonded to the silicon atom of the first silane compound
? '= (molecular weight of the first silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the first silane compound)
? "molecular weight of the hydroxyl group
Tα = content (g) of the first silane compound in the silicon nitride film etching solution
? = number of fluorine free from fluorine-containing compounds
beta '= (molecular weight of fluorine-containing compound) - (sum of atomic amounts of all fluorine contained in fluorine-containing compound)
β "= atomic weight of fluorine
T? = Content of fluorine-containing compound in silicon nitride film etching solution (g)
The method according to claim 1,
Wherein 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 acid, pyrophosphoric acid,
Silicon nitride etch solution.
The method according to claim 1,
Wherein the hydrophilic functional group is a functional group which can be substituted with a hydroxyl group under a pH condition of a hydroxyl group or an inorganic acid aqueous solution,
Silicon nitride etch solution.
The method of claim 3,
The functional group which can be substituted with a hydroxyl group under the pH condition of the aqueous inorganic acid solution may be an amino group, a halogen group, a sulfonic group, a phosphonic group, a phosphoric group, a thiol group, an alkoxy group, an amide group, an ester group, an acid anhydride group, An alkoxy group, an alkoxy group, an alkoxy group,
Silicon nitride etch solution.
The method according to claim 1,
The first silane compound is a silicon nitride film etching solution represented by the following Chemical Formula 1 or Chemical Formula 2:
[Chemical Formula 1]

(here,
R ₁ to R ₄ each independently is a hydrophilic functional group, hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heterocyclic alkyl containing at least one heteroatom, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl is, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, functional group selected from aryl, heteroaryl, aralkyl, aryloxy and silyl siloxanes).

(2)

(here,
R ₅ to R ₁₀ is either a hydrophilic functional group are each independently, hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heterocyclic alkyl containing at least one heteroatom, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ alkyl, and halo, C ₁ -C ₁₀ amino-functional group selected from alkyl, aryl, heteroaryl, aralkyl, aryloxy and silyl siloxanes,
and n is an integer of 1 to 5.)
The method of claim 5, wherein
The hydrophilic functional group may be at least one selected from the group consisting of a hydroxyl group, an amino group, a halogen group, a sulfonic group, a phosphonic group, a phosphoric group, a thiol group, an alkoxy group, an amide group, an ester group, an acid anhydride group, Lt; / RTI &gt;
Silicon nitride etch solution.
The method according to claim 1,
Wherein the fluorine-containing compound is at least one selected from hydrogen fluoride, ammonium fluoride, ammonium fluoride, and ammonium hydrogen fluoride,
Silicon nitride etch solution.
The method according to claim 1,
The fluorine-containing compound is a compound having a form in which an organic cation and a fluorine anion are ionically bonded,
Silicon nitride etch solution.
9. The method of claim 8,
The organic cations are selected from the group consisting of alkylammonium, alkylpyrrolidium, alkylimidazolium, alkylpyrazolium, alkyloxazolium, alkylthiazolium, alkylpyridinium, alkylpyrimidinium, alkylpyridazinium, alkylpyridinium, alkyl Pyrrolidinium, alkylphosphonium, alkylmorpholinium, and alkylpiperidinium.
Silicon nitride etch solution.
9. The method of claim 8,
The fluorine-based anion is selected from fluoride, fluorophosphate, fluoroalkyl-fluorophosphate, fluoroborate, and fluoroalkyl-fluoroborate.
Silicon nitride etch solution.
The method according to claim 1,
Further comprising a second silane compound containing from 1 to 6 silicon atoms and having a maximum of two hydrophilic functional groups bonded to one silicon atom,
Wherein the first silane compound, the fluorine-containing compound and the second silane compound are present in an amount satisfying the following formula 2:
Silicon nitride film etching solution:
[Formula 2]

? = number of hydrophilic functional groups bonded to the silicon atom of the second silane compound
? '(molecular weight of the second silane compound) - (sum of molecular weights of all hydrophilic functional groups bonded to silicon atoms of the second silane compound)
? "= molecular weight of the hydroxyl group
T? = Content of the second silane compound in the silicon nitride film etching solution (g)
12. The method of claim 11,
The second silane compound is a silicon nitride film etching solution represented by the following Chemical Formula 3 and Chemical Formula 4:
(3)

(here,
R ₁₁ to R ₁₄ may be a hydrophilic functional group are each independently, hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heterocyclic alkyl containing at least one heteroatom, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl is, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, functional group selected from aryl, heteroaryl, aralkyl, aryloxy and silyl siloxanes).

[Chemical Formula 4]

(here,
R ₁₅ to R ₂₀ is either a hydrophilic functional group are each independently, hydrogen, C ₁ -C ₁₀ alkyl, C ₆ -C ₁₂ cycloalkyl, C ₂ -C ₁₀ heterocyclic alkyl containing at least one heteroatom, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ alkyl, and halo, C ₁ -C ₁₀ amino-functional group selected from alkyl, aryl, heteroaryl, aralkyl, aryloxy and silyl siloxanes,
and n is an integer of 1 to 5.)
The method of claim 12, wherein
The hydrophilic functional group may be at least one selected from the group consisting of a hydroxyl group, an amino group, a halogen group, a sulfonic group, a phosphonic group, a phosphoric group, a thiol group, an alkoxy group, an amide group, an ester group, an acid anhydride group, Lt; / RTI &gt;
Silicon nitride etch solution.