KR102450687B1 - Etching composition for silicon nitride layer - Google Patents

Abstract

The silicon nitride etching composition of the present invention can selectively etch a silicon nitride film compared to a silicon oxide film, and the etch selectivity is more excellent, and the etching rate and the etch selectivity for the silicon nitride film are changed even when the use time of the composition is increased. There is an excellent effect that is practically absent.

Description

Etching composition for silicon nitride layer

The present invention relates to a silicon nitride etching composition, and to a composition capable of selectively etching a silicon nitride film compared to a silicon oxide film.

A silicon oxide film (SiO ₂ ) and a silicon nitride film (SiN _x ) are representative insulating films used in a semiconductor manufacturing process. These may be used alone, or one or more silicon oxide films and one or more silicon nitride films may be alternately stacked. In addition, the silicon oxide film and the silicon nitride film are also used as a hard mask for forming a conductive pattern such as a metal wiring.

In order to remove the silicon nitride film in the conventional semiconductor manufacturing process, phosphoric acid is used, but phosphoric acid is converted into pyrophosphoric acid or various types of polymeric acid at high temperature, or automatic proton transfer. Deionized water must be supplied because autoprotolysis occurs and affects the etching rates of the nitride film and the oxide film. However, even a small change in the amount of pure water supplied may cause defects in removing the silicon nitride film, and phosphoric acid itself is corrosive as a strong acid, so handling is not easy. In addition, the silicon nitride layer reacts with phosphoric acid to change into H ₂ SiO ₃ form, which is partially dissociated and exists in the solution in the form of silicon ions, and the concentration of silicon ions in the etching composition increases according to Le Chatelier’s principle Accordingly, there is a problem in that the etching rate of the silicon nitride film is significantly reduced.

To solve these problems, various studies have been conducted, and these studies can be classified into three types.

First, it is a technology to increase the etching rate of the silicon nitride film. As an example, an etching method for increasing the selectivity by heating phosphoric acid to obtain polyphosphoric acid and then etching at 100° C. or higher has been proposed, but the effect of improving the selectivity according to the stability and crystal structure of polyphosphoric acid has not been verified. It is difficult to quantify the concentration of phosphoric acid, and it is difficult to control the process temperature due to excessive heat generation during hydration. In addition, since the etching rate of the silicon oxide film also increases, it is difficult to apply the silicon oxide film to a fine process, which is not preferable.

Second, it is a technique for reducing the etching rate of the silicon oxide film. As an example, an etching solution capable of selectively etching a silicon nitride film by adding sulfuric acid, an oxidizing agent, etc. to phosphoric acid has been proposed. However, in the case of adding sulfuric acid, the etching rate of the silicon oxide film as well as the silicon nitride film is reduced, resulting in a decrease in production efficiency. It is not preferable to have

Third, it is a technology for adding a fluorine-based compound. As an example, an etching method for obtaining a high selectivity for a silicon nitride layer by adding a small amount of nitric acid and hydrofluoric acid to phosphoric acid has been proposed, but this has a problem in that the etching rate of the silicon oxide layer increases due to the addition of hydrofluoric acid. As another example, an etching solution capable of selectively etching a silicon nitride layer by adding a silicon-based fluoride has been proposed, but there are problems such as a very short lifespan of the etching solution and poor compatibility with additives.

As described above, studies have been attempted to improve the etching rate of the silicon nitride film in various ways, but all of them cause particles on the surface of the wafer as the processing time increases, which is undesirable for long-term use.

Therefore, it is necessary to develop an etching solution having a new composition that can overcome the above problems.

Accordingly, the present inventors have recognized the limitations of the prior art and have deepened their research. As a result, it is possible to more selectively etch a silicon nitride film compared to a silicon oxide film, and it does not affect the etch selectivity to the silicon nitride film even after long-term use, and the etch rate It provides an etching composition that not only maintains a constant, but also does not cause particle problems.

Korean Patent Publication No. 2012-0077676

An object of the present invention is to provide a silicon nitride etching composition capable of selectively etching a silicon nitride layer compared to a silicon oxide layer, and having an improved etching selectivity.

It is also an object of the present invention to provide a stable silicon nitride layer etching composition in which there is substantially no change in the etching rate and the etching selectivity for the silicon nitride layer even when the treatment time is increased.

It is also an object of the present invention to provide a silicon nitride etching composition that minimizes damage to other films present in the vicinity including a silicon oxide film during a semiconductor manufacturing process, and does not have problems such as generation of particles affecting semiconductor device characteristics. will do

The silicon nitride layer etching composition of the present invention includes an amine-based compound including an acid group and phosphoric acid.

In one embodiment of the present invention, 0.005 to 10% by weight of the amine-based compound and 60 to 98% by weight of the phosphoric acid may be included.

In one embodiment of the present invention, the amine-based compound may include 0.05 to 5% by weight, 75 to 90% by weight of the phosphoric acid, and the balance of water.

In one embodiment of the present invention, the acid group may include any one or two or more selected from a carboxyl group, a sulfone group, and a phosphoric acid group.

In one embodiment of the present invention, the amine-based compound may be an amine-based compound including a carboxyl group. The amine-based compound containing the carboxyl group is carnitine, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine It may include any one or two or more selected from valine, selenocysteine and pyrrolysine.

In one embodiment of the present invention, the amine-based compound may be an amine-based compound including a sulfone group. The amine-based compound containing the sulfone group is aminomethanesulfonic acid, 2-aminoethanesulfonic acid, 3-amino-1-propanesulfonic acid, 4-aminobutane-1-sulfonic acid, and 3-amino-2-methyl-propane-1-sulfonic acid. , Aniline-2-sulfonic acid, sulfanilic acid, 2-morpholinoethanesulfonic acid, N,N-bis(hydroxyethyl)-2-aminoethanesulfonic acid, N-(2-acetamido)-2-aminoethanesulfonic acid , sulfamic acid, methylsulfamic acid, N- cyclohexylsulfamic acid, and may include any one or two or more selected from phenylsulfamic acid.

In one embodiment of the present invention, the amine-based compound may be an amine-based compound including a phosphoric acid group. The amine-based compound containing the phosphoric acid group is phosphorylethanolamine, phosphocholine, phosphoserine, (aminomethyl)phosphonic acid, 2-aminoethylphosphonic acid, 3-aminopropylphosphonic acid, 4-aminobutylphosphonic acid Any one selected from phonic acid, iminodi(methylphosphonic acid), nitrilo(methylphosphonic acid), (1-amino-2-hydroxyethyl)phosphonic acid, and (4-aminobenzyl)phosphonic acid Or it may include two or more.

In one embodiment of the present invention, the amine-based compound may be a compound having C1 to C12 carbon atoms.

In one embodiment of the present invention, it may further include a silicon-based compound.

In one embodiment of the present invention, the silicon-based compound may be represented by the following formula (1). In Formula 1, R ¹ and R ² are each independently selected from hydrogen and (C1-C3)alkyl, and n is an integer of 0 to 3.

[Formula 1]

Si(OR ¹ ) _4-n (R ² ) _n

In an example of the present invention, the etch selectivity ratio of Relation 1-1 below may be satisfied. In Equation 1-1, E _SiNx is the etching rate of the silicon nitride film, and E _SiO2 is the etching rate of the silicon oxide film.

[Relational Expression 1-1]

5 ≤ E _SiNx /E _SiO2

In an example of the present invention, the reduction rate of the etch rate after the iterative etching process may satisfy Relational Equation 2-1 and Equation 3-1 below. In the following Relations 2-1 and 3-1, ΔERD _SiNx is an etch rate decrease rate compared to the initial etch rate for the silicon nitride film, and ΔERD _SiO2 is an etch rate decrease rate compared to the initial etch rate for the silicon oxide film.

[Relational Expression 2-1]

△ERD _SiNx ≤ 5%

[Relational Expression 3-1]

△ERD _SiO2 ≤ 5%

In an example of the present invention, the etching rate for the silicon nitride layer may be 30 to 100 Å/min.

The present invention may provide a method of manufacturing a semiconductor device including an etching process using the silicon nitride etching composition.

The silicon nitride layer etching composition of the present invention can selectively etch a silicon nitride layer compared to a silicon oxide layer, and the etching selectivity is more excellent.

In addition, the silicon nitride layer etching composition of the present invention has an excellent effect that there is substantially no change in the etching rate and the etching selectivity for the silicon nitride layer even when the processing time is increased.

In addition, the silicon nitride film etching composition of the present invention minimizes damage to other films present in the vicinity including the silicon oxide film when used in a semiconductor manufacturing process, and does not have problems such as generation of particles affecting semiconductor device characteristics. There is this.

Even if effects not explicitly mentioned in the present invention, the effects described in the specification expected by the technical features of the present invention and the inherent effects thereof are treated as described in the specification of the present invention.

Hereinafter, the silicon nitride layer etching composition of the present invention will be described in detail.

In addition, if there is no other definition in the technical and scientific terms used in the present invention, it has the meaning commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention is unnecessary in the following description Descriptions of known functions and configurations that may be blurry will be omitted.

In addition, the singular form of a term used in the present invention may be interpreted as including a plural form unless otherwise specified.

In addition, in the present invention, the unit of % used unclearly without special mention means % by weight.

In addition, the 'etch selectivity ratio (E _SiNx /E _SiO2 )' referred to in the present invention refers to the ratio of the etching rate of the silicon oxide layer (E _SiO2 ) to the etching rate of the silicon nitride layer (E _SiNx ). In addition, when the etch rate of the silicon oxide layer approaches zero or the etch selectivity value is large, it means that the silicon nitride layer can be etched more selectively.

The present invention relates to a silicon nitride layer etching composition for selectively etching a silicon nitride layer compared to a silicon oxide layer, wherein the silicon nitride layer etching composition of the present invention includes an amine-based compound, phosphoric acid, and water, and the amine-based compound includes an acid group characterized. By using the amine-based compound containing an acid group in this way, selective etching of the silicon nitride layer is possible, the selectivity thereof is high, and the generation of particles, which has been a problem in the conventional etching process, is prevented, and thus the stability and reliability of the process are secured.

The acidic group may include any one or two or more selected from a carboxyl group, a sulfone group, and a phosphoric acid group. That is, the amine compound used in the present invention is an amine compound containing a carboxyl group, an amine compound containing a sulfone group, an amine compound containing a phosphoric acid group, or an amine compound containing any two or more selected from these acidic groups. may be, and two or more of these amine-based compounds may be used in combination.

As a specific example, the amine-based compound may be an amine-based compound including a carboxyl group. The amine-based compound including the carboxyl group may mean an amino acid, and the type thereof is not particularly limited, but may include a vitamin-based compound such as carnitine, α-amino acid, and the like. In a more specific example, the α-amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. , and may include any one or two or more selected from selenocysteine and pyrrolysine.

As a specific example, the amine-based compound may be an amine-based compound including a sulfone group. The amine-based compound containing the sulfone group is not particularly limited, but for example, aminomethanesulfonic acid, 2-aminoethanesulfonic acid, 3-amino-1-propanesulfonic acid, 4-aminobutane-1-sulfonic acid, and 3-amino-2-methyl -Propane-1-sulfonic acid, aniline-2-sulfonic acid, sulfanilic acid, 2-morpholinoethanesulfonic acid, N,N-bis(hydroxyethyl)-2-aminoethanesulfonic acid, N-(2-acetamido) -2-aminoethanesulfonic acid, sulfamic acid, methylsulfamic acid, N-cyclohexylsulfamic acid, phenylsulfamic acid, and the like may include any one or two or more selected.

As a specific example, the amine-based compound may be an amine-based compound including a phosphoric acid group. The amine-based compound containing the phosphoric acid group is not particularly limited, but for example, phosphorylethanolamine, phosphocholine, phosphoserine, (aminomethyl)phosphonic acid, 2-aminoethylphosphonic acid, and 3-aminopropylphosphonic acid. , 4-aminobutylphosphonic acid, iminodi(methylphosphonic acid), nitrilo(methylphosphonic acid), (1-amino-2-hydroxyethyl)phosphonic acid and (4-aminobenzyl)phosphonic acid It may include any one or two or more selected from nic acid and the like.

The amine-based compound may be a C1 to C12 compound, preferably a C1 to C10 compound, and more preferably a C1 to C6 compound.

The phosphoric acid serves to etch the silicon nitride layer by providing hydrogen ions in the composition and maintaining high-temperature process conditions.

The nitride layer etching composition according to an embodiment of the present invention comprises 0.005 to 10% by weight of an amine compound and 60 to 98% by weight of phosphoric acid, preferably 0.01 to 5% by weight of an amine compound and 70 to 95% by weight of phosphoric acid, more preferably 0.05 to 5 wt% of the amine-based compound and 75 to 90 wt% of phosphoric acid may be included. If this is satisfied, the silicon nitride film can be selectively etched with excellent stability during a high-temperature semiconductor etching process as well as effectively suppressing particle generation, and a stable etch rate and etch selectivity can be provided to the silicon nitride film even after repeated etching processes. have.

The silicon nitride layer etching composition of the present invention includes a residual amount of water based on the total weight of the composition, and specifically, water is 1 to 30% by weight, preferably 1 to 25% by weight, more preferably 5% by weight based on the total weight of the composition. to 20% by weight. The water is not particularly limited, but is preferably deionized water, more preferably deionized water for a semiconductor process, and may have a specific resistance value of 18 MΩ·cm or more. However, this is only a preferred example, and of course, the present invention is not limited thereto.

The nitride layer etching composition according to an embodiment of the present invention may further include a silicon-based compound. When the silicon-based compound is further included, the etch selectivity for the silicon nitride layer compared to the silicon oxide layer can be remarkably improved.

At this time, the silicon-based compound may be included in the composition in an amount of 1 to 200 parts by weight, preferably 3 to 100 parts by weight, more preferably 5 to 50 parts by weight based on 100 parts by weight of the amine-based compound.

It may be preferable that the silicon-based compound is specifically represented by the following formula (1). In Formula 1, R ¹ and R ² are each independently selected from hydrogen and (C1-C3)alkyl, and n is an integer of 0 to 3.

[Formula 1]

Si(OR ¹ ) _4-n (R ² ) _n

As a non-limiting example of the silicon-based compound, any one or two or more selected from tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate and orthosilicic acid (orthosilicic acid). In terms of being able to more significantly increase the etching selectivity, it may be more preferably tetraalkyl orthosilicate, but this is only a preferred example, and the present invention is not limited thereto.

The silicon nitride layer etching composition according to an embodiment of the present invention may further include any additives commonly used in the art. The optional additives may include any one or two or more selected from surfactants, antioxidants, corrosion inhibitors, and the like, but in addition to this, various additives may be used. In this case, the optional additive may be further included in an amount of 0.01 to 10% by weight based on the total weight of the composition, but is not limited thereto.

The silicon nitride etching composition according to an embodiment of the present invention has an etch selectivity of the following relation 1-1 (E _SiNx /E _SiO2 ), specifically, an etch selectivity of the following relation 1-2 (E _SiNx /E _SiO2 ), preferably may satisfy the etch selectivity (E _SiNx /E _SiO2 ) of the following relation 1-3, more preferably, the etch selectivity (E _SiNx /E _SiO2 ) of the following relation 1-3. In the following Relations 1-1, 1-2, 1-3, and 1-4, E _SiNx is the etching rate of the silicon nitride layer, and E _SiO2 is the etching rate of the silicon oxide layer.

[Relational Expression 1-1]

5 ≤ E _SiNx /E _SiO2

[Relational Expression 1-2]

5 ≤ E _SiNx /E _SiO2 ≤ 500

[Relationship 1-3]

7 ≤ E _SiNx /E _SiO2 ≤ 300

[Relational Expression 1-4]

10 ≤ E _SiNx /E _SiO2 ≤ 250

The 'etch selectivity (E _SiNx /E _SiO2 )' referred to in the present invention refers to a ratio of the etch rate (E _SiO2 ) of the silicon oxide layer to the etch rate (E _SiNx ) of the silicon nitride layer. In addition, when the etch rate of the silicon oxide layer approaches zero or the etch selectivity value is large, it means that the silicon nitride layer can be etched more selectively.

In the silicon nitride layer etching composition according to an embodiment of the present invention, the etch rate reduction rate after the repeated etching process may satisfy the following Relational Equation 2-1, specifically, the following Relational Equation 2-2, the following Relational Equation 3-1, specifically It may satisfy Relation 3-2. In the following Relations 2-1, 2-2, 3-1, and 3-2, ΔERD _SiNx is the etch rate decrease rate compared to the initial etch rate for the silicon nitride film, and ΔERD _SiO2 is the etch rate compared to the initial etch rate for the silicon oxide film is the rate of decrease. The silicon nitride layer etching composition according to an embodiment of the present invention has the advantage of being very stable and excellent in process efficiency because there is little change in the etching selectivity even after repeated use.

[Relational Expression 2-1]

△ERD _SiNx ≤ 5%

[Relational Expression 2-2]

0.1 ≤ ΔERD _SiNx ≤ 5%

[Relational Expression 3-1]

△ERD _SiO2 ≤ 5%

[Relational Expression 3-2]

0.001% ≤ △ERD _SiO2 ≤ 5%

The 'Etch rate drift (ΔERD)' referred to in the present invention refers to the rate of change of the etch rate compared to the initial etch rate when the etch process is repeated (two or more times) using the same etch composition. Specifically, the etch rate reduction rate ΔERD is calculated by Equation 1 below. In Equation 1 below, n is a natural number of 2 or more.

[Equation 1]

△ERD(%) = [1 - {(etch rate when used more than n times) / (etch rate when used once)}]×100

In general, as the etching process is repeatedly performed, the etchability, that is, the etch rate, tends to decrease, so it is defined as a decrease rate as a measure thereof, and the rate of change is also interpreted in the same sense.

In addition, in the silicon nitride etching composition according to an embodiment of the present invention, the change in the etch selectivity may be 0.5 or less, preferably 0 to 0.4 or less, and more preferably 0 to 0.3 or less, even after repeated etching processes. That is, there is little change in the etch selectivity even after repeated use, so it is very stable and has excellent process efficiency.

The 'change in etch selectivity' referred to in the present invention means an absolute value of the difference in etch selectivity compared to the initial etch selectivity when the etch process is repeatedly performed two or more times using the same etch composition.

In the silicon nitride etching composition according to an embodiment of the present invention, the etching rate for the silicon nitride layer may be 30 to 200 Å/min, preferably 40 to 200 Å/min, more preferably 50 to 200 Å/min, 50 to 100 Å/min.

Since the silicon nitride layer etching composition according to an embodiment of the present invention includes an amine-based compound having an acidic group, when the silicon nitride layer and the silicon oxide layer are mixed, the silicon nitride layer is selected while hardly affecting the etching on the silicon oxide layer. It can be etched quickly and does not cause particles on the surface of the substrate, thereby minimizing defects in manufacturing semiconductor devices.

In addition, the silicon nitride film etching composition according to an embodiment of the present invention implements high temperature stability to effectively suppress the etching of the silicon oxide film by phosphoric acid heated to a high temperature, so that foreign substances do not occur and substrate defects can be prevented, and the silicon nitride film By selectively etching, excellent semiconductor device characteristics can be realized.

The present invention provides a method of selectively etching a silicon nitride layer compared to a silicon oxide layer using the etching composition. In this case, the etching method may be performed according to a method commonly used in the art.

As a specific example of the etching method, depositing a silicon oxide film on a substrate, depositing a silicon nitride film on the silicon oxide film, forming a photoresist film on the silicon nitride film and then patterning, and the present invention It may include the step of selectively etching the silicon nitride film on which the patterned photoresist film is formed using the etching composition of the.

At this time, the silicon oxide film, silicon nitride film, photoresist film, etc. formed on the substrate may be formed as a single film, a double film, or a multilayer (multilayer film), respectively. is of course

In addition, as the substrate, silicon, quartz, glass, silicon wafer, polymer, metal, metal oxide, etc. may be used, but is not limited thereto. As the polymer substrate, a film substrate such as polyethylene terephthalate, polycarbonate, polyimide, polyethylene naphthalate, cycloolefin polymer, etc. may be used, but limited thereto doesn't happen

According to the etching method according to an embodiment of the present invention, a more stable etching is possible because a particle problem is not caused in spite of performing an iterative etching process. In addition, by selectively etching the silicon nitride layer, it is possible to effectively prevent the silicon oxide layer from being excessively removed or damaged.

The 'silicon nitride film' referred to in the present invention is a concept including a SiN film, a SiON film, a doped SiN film, and the like, and may mean a film quality mainly used as an insulating film when forming a gate electrode.

In addition, the 'silicon oxide film' referred to in the present invention is not limited as long as it is a silicon oxide film commonly used in the art, but for example, a Spin On Dielectric (SOD) film, a High Density Plasma (HDP) film, and a thermal oxide film. , BPSG (Borophosphate Silicate Glass) film, PSG (Phospho Silicate Glass) film, BSG (Boro Silicate Glass) film, PSZ (Polysilazane) film, FSG (Fluorinated Silicate Glass) film, LPTEOS (Low Pressure Tetra Ethyl Ortho Silicate) film, PETEOS (Plasma Enhanced Tetra Ethyl Ortho Silicate) Film, HTO (High Temperature Oxide) Film, MTO (Medium Temperature Oxide) Film, USG (Undoped Silicate Glass) Film, SOG (Spin On Glass) Film, APL (Advanced Planarization Layer) Film , an atomic layer deposition (ALD) film, a plasma enhanced oxide (PE) film, an O3-tetra ethyl ortho silicate (O3-TEOS) film, and combinations thereof.

In this case, the silicon oxide film or the silicon nitride film may be formed in various thicknesses depending on the purpose, for example, it is preferable to be formed to a thickness of 100 to 500 Å, but is not limited thereto.

The present invention also provides a method of manufacturing a semiconductor device including an etching process performed using the silicon nitride etching composition. In this case, the type of the semiconductor device is not particularly limited in the present invention.

The process of etching a nitride film using the silicon nitride film etching composition according to an embodiment of the present invention may be performed according to a method well known in the art, and examples include a dipping method and a spraying method.

The silicon nitride film etching composition according to an embodiment of the present invention may be preferably performed at a high temperature during the etching process, and specifically, the process temperature may be 50 to 300 °C, preferably 100 to 200 °C, but the appropriate temperature is different It can be changed as needed taking into account process and other factors.

According to the method for manufacturing a semiconductor device including an etching process performed using the silicon nitride etching composition according to the present invention, when the silicon nitride layer and the silicon oxide layer are alternately stacked or mixed, selective etching of the silicon nitride layer is possible. In addition, it is possible to secure the stability and reliability of the process by preventing the generation of particles, which has been a problem in the conventional etching process.

Therefore, in the present invention, the etching process can be efficiently applied to various processes requiring selective etching of the silicon nitride layer with respect to the silicon oxide layer.

Hereinafter, the present invention will be described in detail by way of Examples, but these are for describing the present invention in more detail, and the scope of the present invention is not limited by the Examples below.

After mixing each component in the composition ratio shown in Table 1 below, a silicon nitride etching composition was prepared by stirring at a speed of 500 rpm at room temperature for 5 minutes. The content of water was set as the remaining amount such that the total weight of the composition was 100% by weight.

[Examples 2 to 7]

A silicon nitride layer etching composition was prepared in the same manner as in Example 1, except that the composition was changed as shown in Table 1 below.

[Comparative Examples 1 to 3]

A silicon nitride layer etching composition was prepared in the same manner as in Example 1, except that the composition was changed as described in Table 1 below.

Phosphoric acid (wt%) amine compounds additive water (wt%) ingredient Content (wt%) ingredient Content (wt%) Example 1 85 A 0.2 - - remaining amount Example 2 85 A 0.2 S 0.03 Example 3 85 B 0.2 - - Example 4 85 C 0.2 - - Example 5 85 D 0.2 - - Example 6 85 E 0.2 - - Example 7 85 F 0.2 - - Comparative Example 1 85 - - - - Comparative Example 2 85 N 0.2 - - Comparative Example 3 85 - - S 0.03 A: Carnitine
B: Serine
C: 2-aminoethanesulfonic acid
D: Sulfamic acid
E: Phosphorylethanolamine
F: 2-aminoethylphosphonic acid
N: Ammonium chloride
S: Tetraethylorthosilicate

Measurement of etching amount and etch rate of silicon nitride film and silicon oxide film

In order to evaluate the etching performance of each of the etching compositions prepared in Examples 1 to 7 and Comparative Examples 1 to 3, it was deposited in the same manner as in the semiconductor manufacturing process by chemical vapor deposition (CVD) to form silicon. A nitride film (SiN film) wafer and a silicon oxide film (LPTEOS film) wafer were prepared, respectively.

Before starting the etching using each of the etching compositions, the thickness before etching was measured using an ellipsometer (Ellipsometer, NANO VIEW, SEMG-1000), which is a thin film thickness measuring device. The etching process was performed by immersing the wafer in each of the etching compositions maintained at an etching temperature of 157° C. for 10 minutes in a quartz bath. After the etching was completed, it was washed with ultrapure water and then the remaining etchant and moisture were completely dried using a drying device. This etching process was evaluated by performing 10 batches in a method of repeatedly using the etching process as one batch without exchanging the etching composition.

At this time, the etching rate was calculated by dividing the difference between the thickness before etching and the thickness after etching by the etching time (minutes) using an ellipsometer (Ellipsometer, J.A WOOLLAM, M-2000U), and the results are shown in Table 2 and Tables below. 3 is described.

Evaluation of Selective Etching Characteristics of Silicon Nitride Film to Silicon Oxide Film

From the results of measuring the etch rate and the etch rate of the silicon nitride film and the silicon oxide film, the etch selectivity ratio (the etch rate of the silicon nitride film / the etch rate of the silicon oxide film) was determined by the ratio of the etch rate of the silicon nitride film and the etch rate of the silicon oxide film. It was calculated and shown in Tables 2 and 3 below.

Example arrangement Etching rate (Å/min) etch selection Etching rate decrease (%) particle generation SiN _x SiO ₂ E _SiNx /E _SiO2 SiN _x SiO ₂ One One 63.61 5.84 10.89 - - × 4 63.59 5.84 10.89 0.03 0.00 × 7 63.57 5.83 10.90 0.06 0.17 × 10 63.52 5.82 10.91 0.14 0.34 × 2 One 59.55 0.32 186.09 - - × 4 59.51 0.32 185.97 0.07 0.00 × 7 59.49 0.32 185.91 0.10 0.00 × 10 59.47 0.32 185.84 0.13 0.00 × 3 One 62.75 5.64 11.13 - - × 4 62.61 5.64 11.10 0.22 0.00 × 7 62.55 5.63 11.11 0.32 0.18 × 10 62.51 5.61 11.14 0.38 0.53 × 4 One 63.58 5.57 11.41 - - × 4 63.49 5.57 11.40 0.14 0.00 × 7 63.44 5.57 11.39 0.22 0.00 × 10 63.41 5.56 11.40 0.27 0.18 × 5 One 62.11 5.43 11.44 - - × 4 61.97 5.43 11.41 0.23 0.00 × 7 61.82 5.40 11.45 0.47 0.55 × 10 61.68 5.38 11.46 0.69 0.92 × 6 One 62.88 5.91 10.64 - - × 4 62.82 5.91 10.63 0.10 0.00 × 7 62.75 5.86 10.71 0.21 0.85 × 10 62.64 5.81 10.78 0.38 1.69 × 7 One 62.78 5.94 10.57 - - × 4 62.71 5.89 10.65 0.11 0.84 × 7 62.68 5.86 10.70 0.16 1.35 × 10 62.65 5.83 10.75 0.21 1.85 ×

comparative example arrangement Etching rate (Å/min) etch selection Etch rate decrease (%) particle generation SiN _x SiO ₂ E _SiNx /E _SiO2 SiN _x SiO ₂ One One 60.21 11.30 5.33 - - ○ 4 60.05 8.31 7.23 0.27 26.46 ○ 7 57.62 6.98 8.26 4.30 38.23 ○ 10 55.13 5.71 9.65 8.44 49.47 ○ 2 One 63.23 13.61 4.65 - - × 4 63.11 13.52 4.67 0.19 0.66 × 7 63.01 12.29 5.13 0.35 9.70 ○ 10 62.14 11.11 5.59 1.72 18.37 ○ 3 One 58.39 0.34 171.74 - - ○ 4 58.21 0.29 200.72 0.31 14.71 ○ 7 55.30 0.21 263.33 5.29 38.24 ○ 10 52.11 0.16 325.69 10.76 52.94 ○

As shown in Tables 2 and 3, the silicon nitride etching compositions of Examples 1 to 7 not only have excellent etching selectivity for the silicon nitride film compared to the silicon oxide film, but also etch the etching process while repeatedly performing the etching process. It can be seen that there is almost no change in performance (eg, an etch rate and an etch selectivity with respect to a silicon nitride layer) and is stable.

In addition, when the silicon nitride film etching composition of Examples 1 to 7 further includes a silicon-based compound such as tetraethylolthosilicate, the etching selectivity of the silicon nitride film compared to the silicon oxide film is significantly improved by 16 times or more without lowering the etching ability. It was confirmed that it can be done.

In addition, it can be seen that the silicon nitride etching compositions of Examples 1 to 7 do not cause problems such as particles on the substrate after the etching process, thereby minimizing the defect rate of the manufactured semiconductor device.

On the other hand, the etching compositions of Comparative Examples 1 to 3 were not suitable for etching the silicon nitride layer because particles were generated at the first or more times. Specifically, in Comparative Examples 1 to 3, problems such as low etch selectivity or formation of particles occurred because an amine-based compound having an acid group was not used, and thus was not suitable.

Therefore, the silicon nitride layer etching composition can selectively etch the silicon nitride layer, and can significantly increase production efficiency by substantially maintaining the initial etching ability despite long-term use. In addition, it can be seen that it is possible to provide a high-quality semiconductor device by minimizing damage to the film quality of the silicon oxide film during the etching process and at the same time effectively preventing the generation of particles.

Claims (13)

A silicon nitride film etching composition comprising 0.005 to 10% by weight of an amine compound including any one or two or more selected from a carboxyl group, a sulfone group, and a phosphoric acid group, 60 to 98% by weight of phosphoric acid, and the remainder of water,
The amine compound containing the carboxyl group is carnitine, alanine, arginine, asparagine, cysteine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, selenocysteine And any one or two or more amino acids selected from pyrrolysine,
The amine-based compound containing the phosphoric acid group is phosphorylethanolamine, phosphocholine, phosphoserine, (aminomethyl)phosphonic acid, 2-aminoethylphosphonic acid, 3-aminopropylphosphonic acid, 4-aminobutylphosphonic acid Any one selected from phonic acid, iminodi(methylphosphonic acid), nitrilo(methylphosphonic acid), (1-amino-2-hydroxyethyl)phosphonic acid, and (4-aminobenzyl)phosphonic acid Or two or more, silicon nitride etching composition. delete delete delete According to claim 1,
The amine-based compound is an amine-based compound containing a sulfone group,
The amine-based compound containing the sulfone group is aminomethanesulfonic acid, 2-aminoethanesulfonic acid, 3-amino-1-propanesulfonic acid, 4-aminobutane-1-sulfonic acid, and 3-amino-2-methyl-propane-1-sulfonic acid. , Aniline-2-sulfonic acid, sulfanilic acid, 2-morpholinoethanesulfonic acid, N,N-bis(hydroxyethyl)-2-aminoethanesulfonic acid, N-(2-acetamido)-2-aminoethanesulfonic acid , sulfamic acid, methylsulfamic acid, N-cyclohexylsulfamic acid, and silicon nitride etching composition comprising any one or two or more selected from phenylsulfamic acid. delete According to claim 1,
The amine-based compound is a silicon nitride layer etching composition having a carbon number of C1 to C12. According to claim 1,
A silicon nitride layer etching composition further comprising a silicon-based compound. 9. The method of claim 8,
The silicon-based compound is a silicon nitride layer etching composition represented by the following formula (1).
[Formula 1]
Si(OR ¹ ) _4-n (R ² ) _n
(In Formula 1, R ¹ and R ² are each independently selected from hydrogen and (C1-C3)alkyl, and n is an integer of 0 to 3) According to claim 1,
A silicon nitride etching composition satisfying the etch selectivity of the following Relational Equation 1-1.
[Relational Expression 1-1]
5 ≤ E _SiNx /E _SiO2
(In Equation 1-1, E _SiNx is the etching rate of the silicon nitride film, and E _SiO2 is the etching rate of the silicon oxide film) According to claim 1,
The etching rate reduction rate after the repeated etching process satisfies the following Relations 2-1 and 3-1.
[Relational Expression 2-1]
△ERD _SiNx ≤ 5%
[Relational Expression 3-1]
△ERD _SiO2 ≤ 5%
(In Relations 2-1 and 3-1, ΔERD _SiNx is the etch rate decrease rate compared to the initial etch rate for the silicon nitride film, and ΔERD _SiO2 is the etch rate decrease rate compared to the initial etch rate for the silicon oxide film) According to claim 1,
A silicon nitride layer etching composition having an etching rate of 30 to 200 Å/min for the silicon nitride layer. A method of manufacturing a semiconductor device comprising an etching process using the silicon nitride layer etching composition of any one of claims 1, 5, and 7 to 12.