CN112480928A

CN112480928A - Silicon etching composition and etching method for silicon substrate by using same

Info

Publication number: CN112480928A
Application number: CN201910856930.XA
Authority: CN
Inventors: 李柏坚; 蔡雅惠; 张乃仁
Original assignee: Lishen Technology Co ltd
Current assignee: Lishen Technology Co ltd
Priority date: 2019-09-11
Filing date: 2019-09-11
Publication date: 2021-03-12

Abstract

The invention discloses a silicon etching composition and an etching method for acting on a silicon substrate, wherein the silicon etching composition comprises by weight percentage: a quaternary ammonium salt compound, ranging from 30 wt.% to 60 wt.% , amine compounds, between 10 wt.% to 30 wt.%, aqueous medium, between 30 wt.% to 40 wt.%. The present invention also includes an etching method for applying the silicon etching composition to a silicon substrate, comprising the following steps: a preparation step, an application step, an etching step and a resting step. The invention replaces tetramethylammonium hydroxide with a relatively safe chemical to reduce harm to human beings and the environment, in addition, it can improve the effect of achieving the same etching rate on different crystal planes, so that the etched circuit pattern forms a vertical outline, The product yield is improved, and the service life of the silicon etching composition is prolonged, and the process time is shortened to reduce the cost.

Description

Silicon etching composition and etching method for silicon substrate by using same

Technical Field

The present invention relates to an etching composition, and more particularly, to a silicon etching composition suitable for silicon and an etching method applied to a silicon substrate.

Background

In the semiconductor process, no matter the surface micro-machining (surface micro-machining) of the front-stage wafer or the bulk micro-machining (bulk micro-machining) of the back-stage circuit diagram transferred to the wafer, an etching technique is used to selectively remove a certain material from the wafer surface, and the etching method can be dry etching (dry etching) and wet etching (wet etching), wherein wet etching is widely used because of its advantages such as low equipment price, high throughput (throughput), high etching selectivity (etching selectivity), etc.

The conventional wet etching technique for silicon wafers (Si wafers) mostly uses acidic solutions such as nitric acid and hydrofluoric acid to etch, but the etching techniques have the disadvantages that the chemical reaction is not directional, and the surrounding polymer compounds are damaged, so that the process is difficult to control. In addition, the chemicals used in wet etching also pose a hazard to human and environmental safety.

Wet etching applied to silicon substrates also produces anisotropic etch results due to different silicon crystal orientations, such as silicon (110), silicon (100), and silicon (111) crystal planes, having different etch rates, and is subsequently applied to the fabrication of crystal plane-related structures, such as etching with tetramethyl ammonium hydroxide (TMAH) -based etch chemistries, which typically produce a V-shaped or inverted pyramid profile, rather than a flat bottom.

In recent years, compared to potassium hydroxide (KOH), alkali metal ions (alkali metals) destroy the electrical property of the oxide layer of a Complementary Metal Oxide Semiconductor (CMOS), tetramethylammonium hydroxide (tmah) has no ions harmful to electronic circuits, is a recent trend of etching solutions because it is compatible with integrated circuit processes, and is less controllable in the surface roughness of silicon crystal planes, for example, hillock formation (hillock formation) often occurs in the silicon (100) crystal plane after anisotropic etching, which affects the flatness of the surface profile.

In view of the above, a practitioner develops an etching method with a flat bottom effect, please refer to the etching composition of taiwan patent No. I598430 and the method of using the same, and the prior art patent provides an etching composition capable of performing anisotropic etching and sigma-shaped recess etching, wherein the opposite sides of the recess are still eroded, and the formation of a vertical and flat profile (profile) of the circuit pattern (pattern) after etching is not satisfactory.

From the above description, the following disadvantages still exist in the prior art:

harm to the environment and the health of workers

The traditional wet etching uses tetramethylammonium hydroxide as an alkaline compound, which is a highly hazardous chemical, highly lethal and non-toxic agent, and not only harms the environment but also poses a great threat to the safety and health of operators.

Secondly, the surface profile is rough and the isotropic effect is poor

Although tetramethyl ammonium hydroxide is used as a basic compound to improve the anisotropic effect and avoid undercut, the etched surface and side surface are not flat, so that a vertical and flat profile (profile) cannot be formed, electrical signals are affected, and the yield of chips is reduced.

Thirdly, the cost is high and the process time is long

The conventional wet etching solution has a low number of working wafers (bath loading) on a silicon substrate, and the same etching throughput must be maintained by increasing the solution update frequency, and in addition to the overall etching time being prolonged, the process is complicated and the overall cost is further increased due to the low solution lifetime.

Therefore, in view of the above-mentioned disadvantages, a need exists in the art for a silicon etching composition and method for etching the silicon etching composition that can improve the anisotropic etching effect, reduce the harm of the etching chemicals to the environment and personnel, and reduce the processing time and cost.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a silicon etching composition, comprising, in weight percent: quaternary ammonium salt compounds, amine compounds and aqueous media.

A quaternary ammonium salt compound of between 30 wt.% and 60 wt.%, wherein the quaternary ammonium salt compound is selected from the group consisting of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAH), tetrapropylammonium hydroxide, trimethylethylammonium hydroxide, 2-hydroxyethyl trimethylammonium hydroxide, 2-hydroxyethyl triethylammonium hydroxide, (2-hydroxyethyl) tripropylammonium hydroxide, (1-hydroxypropyl) trimethylammonium hydroxide, ethyltrimethylammonium hydroxide (ETMAH), diethyldimethylammonium hydroxide, benzyltrimethylammonium hydroxide, choline hydroxide, tetramethylammonium hydroxide (TMAF), tetraethylammonium fluoride, tetrabutylammonium fluoride (TBAF), tetrapropylammonium fluoride, trimethylethylammonium fluoride, (2-hydroxyethyl) trimethylammonium fluoride, 2-hydroxyethyl) triethylammonium fluoride, triethylammonium fluoride (2-hydroxyethyl) and mixtures thereof, (2-hydroxyethyl) tripropylammonium fluoride, (1-hydroxypropyl) trimethylammonium fluoride, ethyltrimethylammonium fluoride, diethyldimethylammonium fluoride and benzyltrimethylammonium fluoride. The amine compound is between 10wt.% and 30 wt.%. The aqueous medium is between 30 wt.% to 40 wt.%.

The invention also provides the silicon etching composition, wherein the amine compound has a carbon number of C₄~C₁₂And (c) one or more of alkyl, alkenyl, alkoxy, and aryl.

Another technical means of the present invention is the silicon etching composition, wherein the aqueous medium is deionized water (DIW).

In another aspect of the present invention, the silicon etching composition further includes an alcohol compound in an amount of 5wt.% to 10 wt.%.

The present invention also provides a silicon etching composition, which further comprises 0.1 wt.% to 5wt.% of a hydroxide.

Another object of the present invention is to provide an etching method for silicon substrate with the silicon etching composition, comprising the steps of: a preparation step, an application step, an etching step and a standing step.

First, in the preparation step, a silicon etching composition is prepared. Next, the silicon etching composition is applied to a silicon substrate in the applying step. The etching step is then carried out to dissolve the silicon substrate with the silicon etching composition from the contact surface towards the center thereof. Finally, in the step of standing, the etching of the silicon substrate is completed after the etching is completed.

In the method for etching a Silicon substrate according to the present invention, the Silicon substrate may be amorphous Silicon (amorphous Silicon), monocrystalline Silicon (a-Silicon) or polycrystalline Silicon (poly Silicon).

In another aspect of the present invention, in the method for etching a silicon substrate, the etching step is performed at a temperature of 50 ℃ to 100 ℃.

In the method for etching a silicon substrate, the applying step is performed by dipping.

In the method for etching a silicon substrate, the applying step is performed by spraying.

The silicon etching composition and the etching method acting on the silicon substrate have the advantages that tetramethyl ammonium hydroxide can be replaced by relatively safe chemicals, harm to human beings and the environment is reduced, the effect of achieving the same etching rate on different crystal faces can be improved, a vertical profile (profile) is formed on an etched circuit pattern (pattern), the product yield is improved, the service life of the silicon etching composition is prolonged, and the processing time is shortened to reduce the cost.

Drawings

FIG. 1 is a block diagram of a preferred embodiment of the silicon etching composition and method of the present invention;

FIGS. 2 through 3 are cross-sectional views of the etching of silicon etching compositions of the present invention using low concentrations of quaternary ammonium salt compounds;

FIGS. 4 through 5 are cross-sectional views of the etching of a silicon etching composition of the present invention using a high concentration of a quaternary ammonium salt compound;

FIGS. 6-7 are cross-sectional views of etching of silicon etching compositions of the present invention using different concentrations of quaternary ammonium salt compounds;

FIGS. 8 to 9 are cross-sectional views illustrating etching of a silicon substrate with the silicon etching composition of the present invention;

FIGS. 10-11 are cross-sectional views of etching compositions based on different concentrations of conventional tetramethylammonium hydroxide;

FIG. 12 is a graph of etch surface profile and rate using a low concentration of a conventional tetramethylammonium hydroxide-based etch composition;

FIG. 13 is a graph comparing the etch rates of a silicon etch composition of the invention with a conventional tetramethyl ammonium hydroxide based etch composition.

Symbolic illustration in the drawings:

101, preparation;

102 an application step;

103, etching;

104 standing.

Detailed Description

The features and technical content of the present invention will be apparent from the following detailed description of preferred embodiments, which is to be read in connection with the accompanying drawings.

The silicon etching composition comprises the following components in percentage by weight: 30 to 60 wt.% quaternary ammonium salt compound, 10 to 30 wt.% amine compound, and 30 to 40 wt.% aqueous medium.

Wherein the quaternary ammonium salt compound is selected from the group consisting of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAH), tetrapropylammonium hydroxide, trimethylethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide, (2-hydroxyethyl) triethylammonium hydroxide, (2-hydroxyethyl) tripropylammonium hydroxide, (1-hydroxypropyl) trimethylammonium hydroxide, ethyltrimethylammonium hydroxide (ETMAH), diethyldimethylammonium hydroxide, benzyltrimethylammonium hydroxide, choline hydroxide, tetramethylammonium hydroxide (TMAF), tetraethylammonium fluoride, tetrabutylammonium fluoride (TBAF), tetrapropylammonium fluoride, trimethylethylammonium fluoride, (2-hydroxyethyl) trimethylammonium fluoride, (2-hydroxyethyl) triethylammonium fluoride, tripropylammonium fluoride, and tripropylammonium fluoride, (1-hydroxypropyl) trimethylammonium fluoride, ethyltrimethylammonium fluoride, diethyldimethylammonium fluoride, and benzyltrimethylammonium fluoride. Preferably, the quaternary ammonium salt compound is CAS NO. 123-41-1 choline hydroxide.

The amine compound may be C₄~C₁₂Preferably triisopropanolamine (C) can be used in combination with one or more of alkyl, alkenyl, alkoxy and aryl of (A)₉H₂₁NO₃) And the like. The amine may inhibit or prevent silicon-based oxides, nitrides, etc. from being etched, but still have a good etch rate on a silicon substrate, such as polysilicon or amorphous silicon, to protect the layers surrounding the silicon, and the aqueous medium may be deionized water (DIW).

It is worth mentioning that an additive may be added to the aqueous medium. The additive may be an alcohol compound, a hydroxide, or a combination thereof.

When the additive is an alcohol compound, 5wt.% to 10wt.% of the alcohol compound may be added to the aqueous medium to prevent the silicon etching composition of the present invention from volatilizing too fast. Preferably, the alcohol compound may be propylene glycol or glycerol to improve the wettability of the silicon etching composition, to slow the loss of aqueous media, and to reduce the surface tension of the solution to allow the chemical solution to contact the target surface.

When the additive is a hydroxide, 0.1 wt.% to 5wt.% of the hydroxide may be added to the aqueous medium. Preferably, the hydroxide is potassium hydroxide (KOH), sodium hydroxide (NaOH), or the like, and the addition of the hydroxide to the silicon etching composition can be used to maintain the chemical reaction and have high etching selectivity, ensuring that the etching strength is consistent with time.

Referring to fig. 1, the etching method according to the silicon etching composition for a silicon substrate includes a preparation step 101, an application step 102, an etching step 103, and a standing step 104.

First, in the preparation step 101, the silicon etching composition of the present invention and the silicon substrate are prepared. The material of the Silicon substrate may be amorphous Silicon (amorphous Silicon), monocrystalline Silicon (a-Silicon) or polycrystalline Silicon (polysilicon), but should not be limited thereto.

Next, the applying step 102 is performed to apply the silicon etching composition to the silicon substrate. Wherein the applying step 102 may be performed by soaking or spraying.

The etching step 103 is then performed, and the silicon etching composition causes dissolution of the silicon substrate from the contact surface towards its center. The etching step 103 is performed at a temperature of 50 ℃ to 100 ℃, preferably, the temperature is set to 80 ℃ to achieve a better etching effect.

The following description of the experimental group and the control group is made

Experimental groups

1 and 2

Experimental groups

1 and 2 of the present invention are the preparation of the silicon etching composition of the present invention, but the proportions are different

In

experimental groups

1 and 2, the quaternary ammonium salt compound is choline hydroxide, the amine is triisopropanolamine, and when the silicon etching composition is prepared, the quaternary ammonium salt compound and the amine compound are dissolved in deionized water (aqueous medium) according to the content shown in table 1, and the amount of the deionized water is adjusted so that the sum of the weight of the quaternary ammonium salt compound, the amine compound, the weight of the deionized water, the weight of the alcohol compound and the weight of the hydroxide is 100%, so as to prepare the silicon etching composition of the

experimental groups

1 and 2 of the present invention.

TABLE 1

	Experimental group 1	Experimental group 2
			Quaternary ammonium salt compound	5 wt.%	49 wt.%
Amines as herbicidesCompound (I)	30 wt.%	30 wt.%
			Aqueous medium	65 wt.%	21 wt.%

Experimental groups 3 and 4

Experimental groups 3 and 4 of the present invention are formulations containing a low concentration of a quaternary ammonium salt compound

Referring to table 2 below and fig. 2 and 3, SEM images of the etching effect test of the silicon substrate using the low concentration quaternary ammonium salt compound at different times are shown. In fig. 2, the silicon substrate was placed in a solution containing 5wt.% choline hydroxide, and the etching depth of the silicon substrate was observed to be about 100 μm after the silicon substrate was placed for 3.5 hours. In fig. 3, the etching depth of the silicon substrate was observed to be about 200 μm after the silicon substrate was left for 7 hours, and it can be understood that the etching depth was doubled as the standing time was doubled, and it is noted that the etching selectivity of each crystal plane, e.g., (100)/(110), may be in the range of 1 to 1.5 to achieve the same etching rate between different crystal planes.

TABLE 2

	Experimental group 3	Experimental group 4
			Quaternary ammonium salt compound	5 wt.%	5 wt.%
Time	3.5 hours	7 hours
			Depth of etching	About 100 μm	About 200 μm

Experimental groups 5 and 6

The test groups 5 and 6 of the present invention are formulations containing a high concentration of a quaternary ammonium salt compound

Referring to table 3 and fig. 4 and 5, experimental groups 5 and 6 are SEM images of the etching effect test on the silicon substrate at different times after increasing the concentration of the quaternary ammonium salt compound. In fig. 4, the silicon substrate was placed in a solution containing 49 wt.% choline hydroxide, and after the silicon substrate was placed for 3.5 hours, the etching depth was observed to be about 100 μm. In FIG. 5, it is observed that the etching depth of the silicon substrate was about 200 μm after the silicon substrate was left to stand for 7 hours, and the etching depth was also doubled as the standing time was doubled. From the experiments of experimental groups 3 to 6, it is known that the etching rates of silicon substrates are not greatly different with high and low concentrations of the quaternary ammonium salt compound, but a relatively flat etching surface profile (profile) can be formed with the quaternary ammonium salt compound having a high concentration.

TABLE 3

	Experimental group 5	Experimental group 6
			Quaternary ammonium salt compound	49 wt.%	49wt.%
Time	3.5 hours	7 hours
			Depth of field	About 100 μm	About 200 μm

Experimental groups 7 and 8

The experimental groups 7 and 8 of the invention are formulas of quaternary ammonium salt compounds with different concentrations

Experimental groups 7 and 8 were set to the same etching time and temperature at different concentrations of choline hydroxide as in table 4 below. Referring to fig. 6, the etching results obtained from experiment group 7 with a low concentration of 5wt.% choline hydroxide showed an etching rate of 0.47 μm/min and a non-uniform etching surface profile. Referring to fig. 7, the etching results obtained from experiment group 8 with 49 wt.% choline hydroxide at a high concentration showed an etching rate of 0.51 μm/min, a slightly faster rate compared to the low concentration, a small difference, and a substantially flat and consistent etched surface profile (profile), and it is evident that the silicon etching composition with the high concentration of choline hydroxide has a better etched surface profile.

TABLE 4

	Experimental group 7	Experimental group 8
			Quaternary ammonium salt compound	5 wt.%	49 wt.%
Time	7 hours	7 hours
			Temperature of	80℃	80℃
Etch Rate (E/R)	0.47μm/min	0.51μm/min

Experimental groups 9 and 10

Number of silicon substrates processed by the etching operation of the invention

Referring to table 5 and fig. 8 and 9, which are SEM images of silicon substrates etched with the silicon etching composition of the present invention, it can be seen from fig. 8 and 9 that the etching rate of the silicon etching composition of the present invention using one day and the etching rate of the silicon etching composition using four days are consistent under the same etching conditions, and the etching effect does not deteriorate with time.

TABLE 5

	Experimental group 9	Experimental group 10
			Number of tablets	0pcs	100 pcs
Depth of field	300μm	300μm
			Number of days	1 day	4 days
Etching time	100 min	100min
			Etch Rate (E/R)	0.6μm/min	0.6 μm/min

Control groups

1, 2, 3

The

control groups

1, 2 and 3 of the invention are the traditional formula containing high and low concentration tetramethyl ammonium hydroxide and the using time

The etching solution compositions of the

control groups

1 and 2 were prepared according to the contents and times shown in table 6 below. Referring to FIG. 10, in comparison 1, the etching result obtained with a low concentration of 2.38wt.% tetramethylammonium hydroxide has an etching rate of 0.20 μm/min and an etching surface profile with high and low hills. Referring to FIG. 11, the etching rate of control 2, which was 0.46 μm/min and was increased by more than one time, was as high as 5% tetramethylammonium hydroxide, but the profile of the etched surface was as rugged as well.

Referring to fig. 12, in comparison group 3, after using the tetramethylammonium hydroxide formulation with a low concentration of 2.38wt.% for four days, it was observed that the etching surface profile still fluctuated, and the etching rate was reduced to 0.1 μm/min, and compared with comparison group 1, the etching rate was only half of that of comparison group 1 except that the flatness of the etching surface profile was greatly different.

TABLE 6

	Control group 1	Control group 2	Control group 3
				Tetramethyl ammonium hydroxide	2.38 wt.%	5 wt.%	2.38 wt.%
Time	12 hours	4 hours	4 days
				Temperature of	80℃	80℃	80℃
Etch Rate (E/R)	0.20μm/min	0.46μm/min	0.10μm/min

Referring to fig. 13, further comparing the conventional low concentration 2.38wt.% tetramethylammonium hydroxide recipe with the fine etching composition recipe of the present invention, setting the number of etching processing pieces of the silicon substrate to 30, and comparing the etching rates of the two at 80 ℃ for 0 hour, 24 hours and 48 hours, respectively, it can be clearly observed from fig. 13 that the etching rate of the fine etching composition recipe of the present invention is 0.6 μm/min, while the etching rate of the conventional low concentration tetramethylammonium hydroxide recipe is 0.2 μm/min, which is three times that of the conventional low concentration tetramethylammonium hydroxide, the etching rate of the recipe of the present invention does not decline with the increase of the usage time, and the etching rate is consistent after 48 hours, while the etching rate of the conventional low concentration 2.38% tetramethylammonium hydroxide recipe has a declining tendency.

As can be seen from the experimental data of the above experimental groups and comparative groups, the quaternary ammonium salt compound formulation with high concentration has a good etching effect, and can indeed form a vertical and flat profile (profile) on the etched circuit pattern (pattern), and the formulation not only has a good etching effect, but also can effectively maintain the same etching rate, and is better than the TMAH formulation in terms of durability.

In the descriptions and safety data sheets of the professional safety and health administration of taiwan ministry of labor and the global chemical harmonization system (GHS), the graphic symbols of choline hydroxide are corrosion, and the graphic symbols of tetramethylammonium hydroxide are skeleton and two intersecting bones, corrosion and health hazards. For example, the contact of choline hydroxide with skin can cause burns, while the contact of tetramethylammonium hydroxide with skin has the fatal possibility, which belongs to the highly fatal and virulent, and the toxicity is much higher than that of choline hydroxide, therefore, the invention replaces tetramethylammonium hydroxide with choline hydroxide, which can greatly reduce the danger of operating personnel, improve the workplace safety and improve the environmental hazard.

From the above description, it can be seen that the silicon etching composition and the etching method applied to the silicon substrate of the present invention have the following advantages:

one, good isotropic etching effect

The silicon etching composition has high selectivity to silicon, and the layered objects surrounding silicon, such as silicon oxide, silicon nitride and the like, can not be damaged by being exposed to wet etching chemicals at the same time.

Secondly, has the advantage of cost

The silicon etching composition solution of the invention has stable strength, and the etching rate is not gradually reduced due to the increase of the operation time, so that the solution updating operation can be reduced, the operation process can be simplified, and the number of etching operation sheets can be increased. Because the service life of the silicon etching composition solution is longer than that of the traditional formula, the etching rate consistency between wafers or batches can be ensured, and the manufacturing cost of chips is further reduced.

Thirdly, the safety of the working environment is improved

According to the descriptions of the global chemical harmonization system (GHS), sigma aldrich and chemical book of the Ministry of labor, Taiwan, compared with the traditional formula of tetramethylammonium hydroxide, the silicon etching composition of the invention is used for replacing the use of the tetramethylammonium hydroxide solution, so that the danger of operating personnel can be greatly reduced, the workplace safety is improved, and the harm to the environment caused by the use of the tetramethylammonium hydroxide solution is reduced.

In summary, the silicon etching composition and the etching method thereof applied to the silicon substrate of the present invention can replace tetramethylammonium hydroxide with relatively safe chemicals without etching high molecular polymers surrounding the silicon substrate, such as silicon oxide, etc., thereby effectively improving anisotropic etching and increasing the number of processed wafers in silicon substrate operation by wet etching.

The above description is only a preferred embodiment of the present invention, and the scope of the present invention should not be limited thereby, and all the simple equivalent changes and modifications made according to the claims and the description of the present invention are within the scope of the present invention.

Claims

1. A silicon etching composition comprising, in weight percent:

a quaternary ammonium salt compound of between 30 wt.% and 60 wt.%, wherein the quaternary ammonium salt compound is selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, trimethylethylammonium hydroxide, 2-hydroxyethyl trimethylammonium hydroxide, (2-hydroxyethyl) triethylammonium hydroxide, (2-hydroxyethyl) tripropylammonium hydroxide, (1-hydroxypropyl) trimethylammonium hydroxide, ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, benzyltrimethylammonium hydroxide, choline hydroxide, tetramethylammonium hydroxide fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride, tetrapropylammonium fluoride, trimethylethylammonium fluoride, 2-hydroxyethyl trimethylammonium fluoride, (2-hydroxyethyl) triethylammonium fluoride, (2-hydroxyethyl) tripropylammonium fluoride, tetrabutylammonium fluoride, (1-hydroxypropyl) trimethylammonium fluoride, ethyltrimethylammonium fluoride, diethyldimethylammonium fluoride, and benzyltrimethylammonium fluoride;

an amine compound between 10wt.% and 30 wt.%; and

an aqueous medium between 30 wt.% and 40 wt.%.

2. The silicon etching composition as set forth in claim 1, wherein the amine compound is C₄~C₁₂And one or more of alkyl, alkenyl, alkoxy, and aryl.

3. The silicon etching composition of claim 1, wherein the aqueous medium is deionized water.

4. The silicon etching composition of claim 1, further comprising an alcohol compound in an amount of 5wt.% to 10 wt.%.

5. The silicon etching composition of claim 1, further comprising a hydroxide in an amount between 0.1 wt.% and 5 wt.%.

6. An etching method for silicon substrate with the silicon etching composition as set forth in any one of claims 1 to 5, comprising the steps of:

a preparation step of preparing a silicon etching composition according to any one of claims 1 to 5;

an applying step of applying the silicon etching composition to a silicon substrate;

an etching step in which the silicon etching composition dissolves the silicon substrate from the contact surface toward the center thereof; and

a step of standing, wherein the etching of the silicon substrate is completed after the etching is finished.

7. The method of claim 6, wherein the silicon substrate is amorphous silicon, single crystal silicon or polycrystalline silicon.

8. A method for etching a silicon substrate according to claim 6, wherein the etching step is carried out at a temperature of 50 ℃ to 100 ℃.

9. A method for etching a silicon substrate according to claim 6, wherein the applying step is performed by dipping.

10. A method for etching a silicon substrate according to claim 6, wherein the applying step is performed by spraying.