JP7390808B2 - silicon substrate etching solution - Google Patents

Description

The present invention relates to a silicon substrate etching solution, and more particularly, the present invention relates to a silicon substrate etching solution that is capable of increasing the etching selectivity of a silicon oxide film to a silicon nitride film when etching a silicon nitride film, and has improved high temperature safety. Regarding solutions.

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. This may cause problems such as the occurrence of etching, so it is necessary to further reduce the etching rate of the silicon oxide film.

Accordingly, silicon additives have recently been used in conjunction with phosphoric acid to increase the etching rate of silicon nitride films while decreasing the etching rate of silicon oxide films.

SUMMARY OF THE INVENTION An object of the present invention is to provide a silicon substrate etching solution that can increase the selectivity of a silicon oxide film to a silicon nitride film by using a silicon additive.

Another object of the present invention is to provide a silicon substrate etching solution that can prevent the silicon additive from being decomposed and discolored at high temperatures by using a silicon additive that is highly safe at high temperatures.

In order to solve the above-mentioned technical problem, according to one aspect of the present invention, a silicon substrate etching method containing a silicon additive containing phosphoric acid and at least one of compounds represented by the following chemical formulas 1 and 2 is provided. A solution is provided.

[Chemical formula 1]

[Chemical 2]

Here, R ₁ and R ₂ 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 The functional group is selected from alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, and aralkyl.

Furthermore, R ₃ is 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 The functional group is selected from alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, and aralkyl.

Further, X, Y and Z are each independently a functional group selected from hydrogen, sulfate, phosphate, acetate, halogen, and nitro, and in this case, at least one of X, Y, and Z is not hydrogen, and n is a constant between 1 and 3.

The silicon substrate etching solution according to the present invention may further include a fluorine-containing compound, where the fluorine-containing compound is selected from hydrogen fluoride, ammonium fluoride, ammonium bifluoride, and ammonium hydrogen fluoride. It may be a compound having a form in which an organic cation and a fluorine anion are ionicly bonded.

The silicon substrate etching solution according to the present invention forms a protective film on the silicon oxide film by using a silicon additive in which a silicon central element is combined with at least one substituted benzene ring, and the silicon oxide film is removed by the etching solution. Etching can be reduced. Thereby, the etching selectivity of the silicon substrate etching solution for the silicon oxide film and the silicon nitride film can be improved.

In addition, the silicon central element of the silicon additive used in the silicon substrate etching solution according to the present invention is not easily decomposed under the etching conditions (high temperature) because it is blocked by the bulky benzene ring with steric hindrance. It can prevent silicone additives from decomposing and discoloring.

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, and may be embodied in various different forms. It is provided to fully convey the scope of the invention to those skilled in the art, and the invention is defined only by the scope of the claims that follow.

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

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

The silicon substrate to be etched by the silicon substrate etching solution according to the present invention preferably includes at least a silicon oxide film (SiO _x ), and includes a silicon oxide film and a silicon nitride film (Six _{N y} , SI _x O _y N _z ). May also contain both. 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) and the like.

Here, phosphoric acid is a substance that etches the silicon nitride film of the silicon substrate, and also maintains the pH of the etching solution so that various forms of silane compounds present in the etching solution change into silicon-based particles. It is a substance that suppresses

In one embodiment, phosphoric acid is preferably contained in an amount of 60 to 90 parts by weight per 100 parts by weight of the silicon substrate etching solution. Further, the pH of the silicon substrate etching solution used in the present application may be 0 to 6.5. When the pH of the silicon substrate etching solution exceeds 6.5, the acid strength of the silicon substrate etching solution is low, and there is a problem that it is difficult to realize a sufficient etching effect on the silicon substrate. On the other hand, if the pH of the silicon substrate etching solution is less than 1, the acid strength of the silicon substrate etching solution may become too strong, and the etching rate of the silicon oxide film may increase abnormally.

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 will decrease, and the silicon nitride film may not be etched sufficiently or the etching process of the silicon nitride film may be affected. Efficiency may 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 quickly etched. However, 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]

R ₁ and R ₂ in Chemical Formula 1 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 The functional group is selected from alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, and aralkyl.

In addition, a silicon substrate etching solution according to another embodiment of the present invention may include a silicon additive represented by the following formula 2 to increase the selectivity of the silicon oxide film to the silicon nitride film.

[Chemical 2]

R ₃ in Chemical Formula 2 is 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, and aralkyl.

Furthermore, a silicon substrate etching solution according to another embodiment of the present invention may include both a silicon additive represented by Chemical Formula 1 and a silicon additive represented by Chemical Formula 2.

X, Y, and Z in Chemical Formulas 1 and 2 are each independently selected from hydrogen, sulfate, phosphate, acetate, halogen, and nitrite, and Salt, acetate, halogen or nitrite groups are functional groups that improve the solubility of silicon additives in etching solutions. Therefore, it is preferable that at least one of X, Y, and Z has a polar functional group other than hydrogen to ensure sufficient solubility in the silicon substrate etching solution.

Further, n in Chemical Formulas 1 and 2 is a constant between 1 and 3, so that the silicon central element of the silicon additive may be a compound bonded to at least one substituted benzene ring.

At this time, the substituted benzene ring bonded to the silicon central element replaces the hydrogen of silicon-hydroxy (-Si-OH) present on the surface of the silicon oxide film with a benzene ring, thereby creating a protective film on the silicon oxide film. (passivation
layer).

As a result, etching of the silicon oxide film by inorganic acid or the like can be reduced, and a reduction in the etching selectivity of the silicon oxide film to the silicon nitride film can be prevented.

Further, hydrogen of silicon-hydroxy (-Si-OH) present on the surface of the silicon substrate is substituted with a benzene ring, thereby further restricting hydroxylation.

This can reduce the growth of silicic acid-like silicon particles having hydroxyl groups during etching or cleaning after etching, and furthermore, the silicon particles can be separated from the silicon oxide film. Growth and precipitation of silicon-based particles can be prevented.

At least one benzene ring bonded to the silicon central element of the silicon additive represented by Chemical Formula 1 or Chemical Formula 2 corresponds to a bulky functional group, and as a result, the silicon central element can be , can be relatively blocked compared to when a functional group with a small bulk is attached. In this case, the high-temperature safety of the silicone additive is improved by reducing the possibility that the silicone additive will decompose (e.g., functional groups bonded to the silicon center element will decompose) under harsh conditions (e.g., high temperature). This can prevent the silicon substrate etching solution from discoloring due to decomposition of the silicon additive at high temperatures.

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 ).

In addition, alkoxy in this application means 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 or branched chain hydrocarbon having atoms.

Specifically, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy, 1,2-dimethylbutoxy, cyclopropyloxy, cyclobutyloxy, cyclopentyl Including, but 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 (e.g. C ₁ -C ₁₀ straight chain, C ₃ -C ₁₀ branched chain), preferably 4 or less, more preferably 3 or less in the main chain. 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 heteroatom-containing cycloalkyl 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, and cycloheptyl.

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.

Preferably, the silicon additive described above is present in the silicon substrate etching solution in an amount of 100 to 10,000 ppm. If both the silicon additive represented by Chemical Formula 1 and the silicon additive represented by Chemical Formula 2 are used, the silicon additive represented by Chemical Formula 1 and the silicon additive represented by Chemical Formula 2 are Preferably, the sum of the contents is 100 to 10,000 ppm.

When the silicon additive is present at less than 100 ppm in the silicon substrate etching solution, the effect of protecting the silicon oxide film by the silicon additive is weak, and the effect of increasing the selectivity of the silicon oxide film to the silicon nitride film may be weak. .

On the other hand, if the content of the silicon additive in the silicon substrate etching solution exceeds 10,000 ppm, a problem arises in that the etching rate of the silicon nitride film decreases in response to the increased silicon concentration in the silicon substrate etching solution. obtain.

For example, when the content of the silicon additive represented by chemical formula 1 in the silicon substrate etching solution is 500 to 2000 ppm, the etching selectivity of the silicon substrate etching solution (etching rate of silicon nitride film (Å/min)/ The etching rate (Å/min) of the silicon oxide film may be 300 or more.

In addition, when the content of the silicon additive represented by chemical formula 2 in the silicon substrate etching solution is 500 to 2000 ppm, the etching selectivity of the silicon substrate etching solution (etching rate of silicon nitride film (Å/min)/ The etching rate (Å/min) of the silicon oxide film may be 300 or more.

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

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.

Experimental example 1
Composition of Silicon Substrate Etching Solution Table 1 below shows the composition of the silicon substrate etching solution according to the example.

The silicon substrate etching solutions according to Examples 1 to 8 contain 85% by weight of phosphoric acid and the balance water, and contain silicon additives and fluorine-containing compounds in ppm as listed in Table 1.

In Example 8, ammonium fluoride was used as the fluorine-containing compound.

The silicon additives used in the silicon substrate etching solutions according to Examples 1 to 8 are represented by Formula 1 having functional groups shown in Table 2 below.

[Chemical formula 1]

Table 3 below shows the composition of a silicon substrate etching solution according to a comparative example.

The silicon substrate etching solutions according to Comparative Examples 1 to 4 contain 85% by weight of phosphoric acid and the balance water, and contain silicon additives and fluorine-containing compounds in ppm as listed in Table 3.

Comparative Example 1 is a phosphoric acid aqueous solution to which no silicone additive is added.

Comparative Example 2 used tetrahydroxysilane as the silicone additive.

Comparative Example 3 used a compound represented by the following chemical formula 3 as a silicon additive.

[Chemical 3]

Comparative Example 4 used the same silicon additive as Comparative Example 3, but used ammonium fluoride as the fluorine-containing compound.

Etching characteristics and high temperature safety evaluation of silicon substrate etching solution A silicon nitride film and a silicon oxide film were etched at 165° C. for 5 minutes using a silicon substrate etching solution having the composition according to each example and comparative example.

Silicon nitride films and silicon oxide films are planarized before being placed in an etching solution.The planarization work is performed by diluting 50% by mass hydrofluoric acid to 200:1 and then immersing the film in diluted hydrofluoric acid for 30 seconds. I went.

The etching rate is the value calculated by calculating the average etching amount per minute using an ellipsometer after etching the silicon nitride film and the silicon oxide film for 5 minutes at 165°C. The etching selectivity is the etching rate of the silicon oxide film versus the silicon It shows the ratio of etching rates of nitride films.

The silicon substrate etching solution before etching was a transparent solution, and in order to evaluate the high temperature safety of the silicon substrate etching solution, it was visually confirmed whether the silicon substrate etching solution changed color after etching.

The evaluation results are shown in Table 4 below.

Referring to Table 4, it can be confirmed that Examples 1 to 7 have a higher etching selectivity than the comparative example, and the etching solutions do not discolor even at high temperatures.

On the other hand, in the case of Comparative Example 1 using a phosphoric acid aqueous solution to which no silicon additive was added, it can be confirmed that the etching selectivity was the lowest.

On the other hand, in the case of Comparative Example 2 in which tetrahydroxysilane, which is generally used as a silicon additive, was used as a silicon additive, although it showed a somewhat good level of etching selectivity, the color changed to black after etching. It can be confirmed that the safety is low under high temperature etching conditions.

Furthermore, in the case of Comparative Example 3, all benzene rings bonded to the silicon element are substituted with hydrogen elements, and in this case, it may be difficult to ensure sufficient solubility of the silicon additive in the etching solution. This confirms that the effect of increasing the etching selectivity due to the silicon additive in the etching solution is weaker than in the example.

In the case of Example 8 and Comparative Example 4, it can be confirmed that by using a fluorine-containing compound, the etching rate for the silicon oxide film is higher than in other Examples and Comparative Examples. Therefore, it can be confirmed that, due to the high content of the silicon additive in the etching solution of Example 8, the effect of increasing the etching selectivity by the silicon additive is even higher in Example 8.

Experimental example 2
Composition of Silicon Substrate Etching Solution Table 5 below shows the composition of the silicon substrate etching solution according to the example.

The silicon substrate etching solutions according to Examples 9 to 16 contain 85% by weight phosphoric acid and the balance water, and silicon additives and fluorine-containing compounds in ppm as listed in Table 5.

In Example 16, hydrogen fluoride was used as the fluorine-containing compound.

The silicon additive used in the silicon substrate etching solutions according to Examples 9 to 16 is represented by Formula 2 having functional groups shown in Table 6 below.

[Chemical 2]

Table 7 below shows the composition of a silicon substrate etching solution according to a comparative example.

The silicon substrate etching solutions according to Comparative Examples 5 to 8 contain 85% by weight of phosphoric acid and the balance water, and contain silicon additives and fluorine-containing compounds in ppm as listed in Table 7.

Comparative Example 5 is a phosphoric acid aqueous solution to which no silicone additive is added.

Comparative Example 6 used 3-aminopropyltrihydroxysilane as the silicone additive.

Comparative Example 7 used a compound represented by the following chemical formula 4 as a silicon additive.

[C4]

Comparative Example 8 used the same silicone additive as Comparative Example 7, but used hydrogen fluoride as the fluorine-containing compound.

Etching characteristics and high temperature safety evaluation of silicon substrate etching solution A silicon nitride film and a silicon oxide film were etched at 165° C. for 5 minutes using a silicon substrate etching solution having the composition according to each example and comparative example.

Silicon nitride films and silicon oxide films are planarized before being placed in an etching solution.The planarization work is performed by diluting 50% by mass hydrofluoric acid to 200:1 and then immersing the film in diluted hydrofluoric acid for 30 seconds. I went.

The etching rate is the value calculated by calculating the average etching amount per minute using an ellipsometer after etching the silicon nitride film and the silicon oxide film for 5 minutes at 165°C. The etching selectivity is the etching rate of the silicon oxide film versus the silicon It shows the ratio of etching rates of nitride films.

The silicon substrate etching solution before etching was a transparent solution, and in order to evaluate the high temperature safety of the silicon substrate etching solution, it was visually confirmed whether the silicon substrate etching solution changed color after etching.

The evaluation results are shown in Table 8 below.

Referring to Table 8, it can be confirmed that Examples 9 to 16 have higher etching selectivity than the comparative example, and the etching solutions do not discolor even at high temperatures.

On the other hand, in the case of Comparative Example 5 using a phosphoric acid aqueous solution to which no silicone additive was added, it can be confirmed that the etching selectivity was the lowest.

On the other hand, in the case of Comparative Example 6 in which 3-aminopropyltrihydroxysilane, which is generally used as a silicone additive, was used as a silicone additive, although it showed a somewhat good level of etching selectivity, the color changed to black after etching. This confirms that the safety is low under high-temperature etching conditions.

Furthermore, in the case of Comparative Example 7, all benzene rings bonded to the silicon element are substituted with hydrogen elements, and in this case, it may be difficult to ensure sufficient solubility of the silicon additive in the etching solution. This confirms that the effect of increasing the etching selectivity due to the silicon additive in the etching solution is weaker than in the example.

In the case of Example 16 and Comparative Example 8, it can be confirmed that by using a fluorine-containing compound, the etching rate for the silicon oxide film is higher than in other Examples and Comparative Examples. It can be confirmed that the silicon additive has a higher effect of increasing the etching selectivity in Example 16 due to the higher content of the silicon additive in the etching solution of Example 16.

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 present invention.

Claims (8)

phosphoric acid; and
A silicone additive containing at least one of the compounds represented by the following chemical formulas 1 and 2;
including,
Silicon substrate etching solution:
Here, R ₁ and R ₂ 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 a functional group selected from alkenyl, C ₂ -C ₁₀ alkynyl, C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, and aralkyl,
R ₃ is 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, a functional group selected from C ₁ -C ₁₀ haloalkyl, C ₁ -C ₁₀ aminoalkyl, aryl, heteroaryl, and aralkyl;
X, Y, and Z are each independently a functional group selected from hydrogen, sulfate, phosphate, acetate, halogen, and nitro , and at least one of X, Y, and Z is It's not hydrogen,
n is a constant between 1 and 3. The silicon additive is contained in the silicon substrate etching solution in an amount of 100 to 10,000 ppm.
The silicon substrate etching solution according to claim 1. When the content of the silicon additive represented by chemical formula 1 in the silicon substrate etching solution is 500 to 2000 ppm, the etching selectivity of the silicon substrate etching solution (etching rate of silicon nitride film (Å/min)/silicon The etching rate (Å/min) of the oxide film is 300 or more,
The silicon substrate etching solution according to claim 1 . When the content of the silicon additive represented by chemical formula 2 in the silicon substrate etching solution is 500 to 2000 ppm, the etching selectivity of the silicon substrate etching solution (etching rate of silicon nitride film (Å/min)/silicon The etching rate (Å/min) of the oxide film is 300 or more,
The silicon substrate etching solution according to claim 1 . further comprising 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. further comprising a fluorine-containing compound having an ionic bond between an organic cation and a fluorine anion;
The silicon substrate etching solution according to claim 1. The organic cations include alkyl ammonium, alkylpyrrolium, alkylimidazolium, alkylpyrazolium, alkyloxazolium, alkylthiazolium, alkylpyridinium, alkylpyrimidinium, alkylpyridazinium, and alkylpyrazinium. , alkylpyrrolidinium, alkylphosphonium, alkylmophorinium, and alkylpiperidinium,
The silicon substrate etching solution according to claim 6 . The fluorinated anion is selected from fluoride, fluorophosphate, fluoroalkyl-fluorophosphate, fluoroborate, and fluoroalkyl-fluoroborate.
The silicon substrate etching solution according to claim 6 .