KR20230068312A - Etching composition for silicon nitride layer and etching method using the same - Google Patents

Abstract

The present invention relates to a silicon silicide film etching composition and an etching method using the same. More particularly, the present invention relates to an etching composition and an etching method capable of selectively etching only a silicon nitride film while minimizing oxide regrowth in a highly integrated, high aspect ratio vertical NAND stack structure.

Description

Silicon nitride film etching composition and etching method using the same

The present invention relates to a silicon silicide film etching composition and an etching method using the same. More particularly, the present invention relates to an etching composition and an etching method capable of selectively etching only a silicon nitride film while minimizing oxide regrowth in a highly integrated, high aspect ratio vertical NAND stack structure.

A silicon oxide film (SiO _x ) and a silicon nitride film (SiN _x ) are used as typical insulating films in a semiconductor manufacturing process. ) structure memory semiconductor devices are in the limelight.

Silicon nitride film etching technology, which has a high etching selectivity compared to silicon oxide film, is a very important technology in the production of high-density vertical NAND devices, which is one of the current semiconductor mainstream businesses. However, the conventional etching process can realize excellent etching performance when applied to a blanket wafer, but severe oxide regrowth occurs when applied to a highly integrated silicon nitride/silicon oxide layered pattern wafer, and the etching selectivity In addition, there are various problems such as re-filling of the etched region of the silicon nitride film at the bottom of the pattern due to oxide regrowth. In order to solve this problem, if the problem of oxide regrowth is solved by adding additives or adjusting the process temperature, there is a limit to the decrease in the etching selectivity, and if the silicon nitride film at the bottom of the pattern is etched, the silicon oxide is also etched or the oxide regrowth is etched. There is a limit in which the phenomenon becomes more severe.

Moreover, recently, as the number of stacked layers of vertical NAND devices increases and patterns become more fine, the performance requirements of materials for etching silicon nitride films of vertical NAND devices are gradually increasing.

Republic of Korea Patent Registration No. 10-1769349 (2017.08.11.) Republic of Korea Patent Registration No. 10-2315919 (2021.10.15.)

An object of the present invention is to provide an etching composition capable of selectively etching only a silicon nitride film up to the lowermost part of a stacked structure while effectively suppressing etching of a silicon oxide film and oxide regrowth in a highly integrated and high aspect ratio vertical NAND structure. .

One aspect of the present invention is phosphoric acid; Carboxyl group-containing aliphatic organic acids or salts thereof; And it provides a silicon nitride film etching composition containing a chelating agent.

The silicon nitride film etching composition according to an aspect may further include a fluorine-based compound.

The carboxyl group-containing aliphatic organic acid may include oxalic acid, formic acid, citric acid, α-ketoglutaric acid, or a combination thereof.

The chelating agent may include etidronic acid, aminotrimethylenephosphonic acid, N-(2-acetamido)iminodiacetic acid, N-(phosphonomethyl)iminodiacetic acid, or a combination thereof. can

The silicon nitride film etching composition may be characterized in that it does not substantially include a silicon-based compound.

50 to 85% by weight of phosphoric acid, 0.1 to 30% by weight of a carboxyl group-containing aliphatic organic acid or a salt thereof, 0.1 to 20% by weight of a chelating agent, and 0.0001 to 0.1% by weight of a fluorine-based compound, based on the total weight of the silicon nitride film etching composition. there is.

The silicon nitride film etching composition may have an etching selectivity of 500 or more according to Equation 1 below in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers.

[Equation 1]

E _SiNx / E _SiO2

(In Equation 1 above,

E _SiNx is the etch rate for the silicon nitride film;

E _SiO2 is the etching rate for the outside of the silicon oxide film.)

The silicon nitride film etching composition may have an etching rate (Å/min) of 0 to 0.5 for the outside of the silicon oxide film in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers.

In addition, after etching in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers, an outer thickness (T _o ) compared to an inner thickness (T i ₎ of the silicon oxide film may satisfy Equation 2 below.

[Equation 2]

0.75 ≤ T _o /T _i ≤ 1.25

(In Equation 2 above,

T _o is the outer thickness of the silicon oxide film;

T _i is the internal thickness of the silicon oxide film.)

In addition, the silicon nitride film etching composition may have a silicon nitride film etch rate of 50% or more according to Equation 3 below in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers.

[Equation 3]

(D _SiNx / D _NAND ) x 100

(In Equation 3 above,

D _SiNx is the vertical depth of the area where the silicon nitride film is etched relative to the wafer surface;

D _NAND is the vertical depth of the entire wafer structure.)

In addition, one aspect of the present invention provides an etching method comprising the step of selectively etching a silicon nitride film compared to a silicon oxide film using the silicon nitride film etching composition.

An object to be etched in the silicon nitride film etching composition is a wafer on which both a silicon oxide film and a silicon nitride film are exposed; Alternatively, it may be a wafer having a vertically stacked structure including a silicon oxide film and a silicon nitride film as unit layers.

The etching method may be for high-temperature etching of 100 °C or higher.

In addition, one aspect of the present invention provides a method for manufacturing a semiconductor device, including an etching process performed using the silicon nitride film etching composition.

When the silicon nitride film composition according to the present invention is applied to a highly integrated high aspect ratio vertical NAND structure, it is possible to selectively etch only the silicon nitride film while minimizing etching of the silicon oxide film or oxide regrowth occurring around the silicon oxide film. At the same time, the silicon nitride film composition according to the present invention can selectively etch even the lowermost silicon nitride film of the highly integrated high aspect ratio vertical NAND structure, which could not be etched with conventional phosphoric acid.

That is, as the number of stacked layers increases and the pattern becomes finer, it is possible to satisfy the performance requirements of an advanced silicon nitride film etching process and to provide a highly reliable semiconductor device.

1 illustrates a patterned wafer of a vertical NAND structure and the structure after etching thereof.
2 shows a method for obtaining an etch rate and an etch selectivity in a vertical stacked structure according to the present invention.
3 illustrates a method for obtaining a silicon nitride film etch rate with respect to a depth in a vertical direction in a vertical stack structure according to the present invention.

Unless defined otherwise herein, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the description herein are merely to effectively describe specific embodiments and are not intended to limit the invention.

The singular form used herein may be intended to include the plural form as well, unless the context dictates otherwise.

Further, as used herein, numerical ranges include lower and upper limits and all values within that range, increments logically derived from the shape and breadth of the defined range, all values defined therebetween, and the upper limit of the numerical range defined in a different form. and all possible combinations of lower bounds. Unless otherwise specifically defined herein, values outside the numerical range that may occur due to experimental errors or rounding of values are also included in the defined numerical range.

The term "includes" in the present specification is an open description having the same meaning as expressions such as "includes", "includes", "has" or "characterized by", and elements not additionally listed, No materials or processes are excluded.

Hereinafter, each configuration of the present invention will be described in detail. However, this is merely an example and the present invention is not limited to the specific embodiments described as examples.

One aspect of the present invention is phosphoric acid; Carboxyl group-containing aliphatic organic acids or salts thereof; And it provides a silicon nitride film etching composition containing a chelating agent.

As the silicon nitride film etch composition according to one aspect has the above-described configuration combination, excellent etching performance can be implemented. Specifically, when applied to a highly integrated, high-aspect-ratio vertical NAND structure, only the silicon nitride layer can be selectively etched while minimizing etching of the silicon oxide layer or oxide regrowth. At the same time, the silicon nitride film can be etched up to the lowest part of the highly integrated, high-aspect-ratio vertical NAND structure, which could not be etched with conventional phosphoric acid.

Although not bound by a particular theory, for example, when an aromatic organic acid is added instead of the carboxyl group-containing aliphatic organic acid or its salt, oxide regrowth occurs, making it difficult to implement selective etching of the silicon nitride film.

The carboxyl group-containing aliphatic organic acid or salt thereof may be, for example, oxalic acid (C ₂ H ₂ O ₄ ), sodium oxalate (Na ₂ C ₂ O ₄ ), calcium oxalate (CaC ₂ O ₄ ), potassium oxalate (K ₂ C ₂ O ₄ ), dimethyl oxalate ((CO ₂ CH ₃ ) ₂ ) and diethyl oxalate (C ₆ H ₁₀ O ₄ ) oxalate compounds such as; Formic acid (CH ₂ O ₂ ), sodium formate (CHNaO ₂ ), potassium formate (CHKO), methyl formate (C ₂ H ₄ O ₂ ) and ethyl formate Formate compounds such as (ethyl formate, C ₃ H ₆ O ₂ ); Citric acid (C ₆ H ₈ O ₇ ), sodium citrate (Na ₃ C ₆ H ₅ O ₇ ), potassium citrate (K ₃ C ₆ H ₅ O ₇ ), potassium-magnesium citrate compounds such as potassium-magnesium citrate (C ₆ H ₅ KMgO ₇ ) and 2-methylcitric acid (C ₇ H ₁₀ O ₇ ); α-ketoglutaric acid (C ₅ H ₆ O ₅ ), α-ketoglutaric acid sodium salt (C ₅ H ₅ NaO ₅ ), α-ketoglutaric acid disodium salt (C ₅ H ₄ Na ₂ O ₅ ), α-ketoglutaric acid potassium salt (C ₅ H ₅ KO ₅ ) and α-ketoglutaric acid dipotassium salt (C ₅ H ₄ K ₂ O ₅ ), and alpha-ketoglutarate compounds; may be one or two or more selected from there is.

In addition, the chelating agent, for example, etidronic acid, amino trimethylene phosphonic acid, N- (2-acetamido) imino diacetic acid (N- (2-acetamido)iminodiacetic acid (ADA), N-(phosphonomethyl)iminodiacetic acid, ethylene diaminetetraacetic acid, nitrilotrimethylphosphonic acid (nitrilo trimethyl phosphonic acid) or nitrilotriacetic acid. More preferably, the chelating agent may be etidronic acid, aminotrimethylenephosphonic acid, N-(2-acetamido)iminodiacetic acid, or N-(phosphonomethyl)iminodiacetic acid, When combined with other constituent elements according to an aspect, more stable and effective etching performance can be implemented up to the bottom of the vertical NAND structure.

In addition, the silicon nitride film composition according to one aspect may further include a fluorine-based compound. Non-limiting examples of the fluorine-based compound include hydrofluoric acid (HF), ammonium fluoride, ammonium bifluoride, tetramethyl ammonium fluoride, tetraethyl ammonium fluoride, tetrapropyl ammonium fluoride, tetrabutyl ammonium fluoride, tetrapentyl ammonium fluoride, and the like, but are not limited thereto.

A silicon nitride film etching composition according to an aspect of the present invention may not substantially contain a compound containing silicon atoms (Si). The compound containing a silicon atom (Si) may be, for example, an inorganic substance, an organic substance, or a mixture thereof, and a non-limiting example may be silicic acid, phosphoric acid-modified silica (SiO ₂ ) or phosphoric acid-modified silicic acid, It is not limited to this. Substantially not included herein means that it may be present in an amount that does not have an unacceptably significant effect on at least one basic and novel technical idea of the invention. In addition, it means that the effect caused by this is insignificant. Specifically, the compound containing silicon atoms (Si) may mean that it includes 0.001% by weight or less, more specifically 0.0001% by weight or less, based on the total weight of the silicon nitride film etching composition.

That is, the silicon nitride film composition according to one embodiment can implement a high etching ratio of the silicon nitride film compared to the silicon oxide film even without using a silicon-based compound.

Specifically, the silicon nitride film etching composition according to one embodiment includes 50 to 85% by weight of phosphoric acid, 0.1 to 30% by weight of a carboxyl group-containing aliphatic organic acid or a salt thereof, 0.1 to 20% by weight of a chelating agent, and 0.0001 fluorine-based compound, based on the total weight of the composition. to 0.1% by weight. More specifically, it may contain 60 to 85% by weight of phosphoric acid, 1 to 30% by weight of a carboxyl group-containing aliphatic organic acid or a salt thereof, 5 to 20% by weight of a chelating agent, and 0.001 to 0.1% by weight of a fluorine-based compound, based on the total weight of the composition. there is. When the content within the above range is satisfied, the selective etching performance of the silicon nitride film may be further improved without impairing the stability of the composition.

In general, even if a blanket wafer in which both the silicon oxide film and the silicon nitride film are exposed shows a very good etching selectivity (silicon nitride film etch rate/silicon oxide film etch rate), the silicon oxide film and the silicon nitride film are formed as unit layers. In many cases, wafers with a vertical stacked structure having a layered structure exhibit completely different etching characteristics. However, an etch target of the silicon nitride film etching composition according to an aspect of the present invention is a wafer in which both the silicon oxide film and the silicon nitride film are exposed; or a wafer having a laminated structure including the silicon oxide film and the silicon nitride film as unit layers; etc., and may cover all of the stacked forms in various aspects.

In a vertically stacked (NAND) wafer having a silicon oxide film and a silicon nitride film as unit layers according to an embodiment, the etching selectivity according to Equation 1 below may be 500 or more and may reach infinity.

[Equation 1]

E _SiNx / E _SiO2

(In Equation 1 above,

E _SiNx is the etch rate for the silicon nitride film;

E _SiO2 is the etching rate for the outside of the silicon oxide film.)

For example, the silicon nitride film etching composition may have an etch rate (E _SiNx , Å/min) of 50 or more, 60 or more, or 70 or more. At the same time, the silicon nitride film etching composition may have an etching rate (E _SiO2 , Å / min) of 0 to 1 for a silicon oxide film in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers, specifically may be 0 to 0.2. That is, it can be seen that the silicon nitride film etching composition according to one embodiment selectively etches only the silicon nitride film without etching the silicon oxide film at all.

In addition, the silicon nitride film etching composition has a silicon oxide film and a silicon nitride film as unit layers, and after etching in a NAND wafer, the outer thickness (T _o ) compared to the inner thickness (T _i ) of the silicon oxide film is expressed by Equation 2 below: may be satisfactory.

[Equation 2]

0.75 ≤ T _o /T _i ≤ 1.25

(In Equation 2 above,

T _o is the outer thickness of the silicon oxide film;

T _i is the internal thickness of the silicon oxide film.)

As shown in FIG. 2 below, specifically, the inner thickness (T _i ) of the silicon oxide film means the thickness of the silicon oxide film measured at the end of the etching depth direction where the silicon nitride film is etched, and the outer thickness of the silicon oxide film ( T _o ) may mean the thickness of the silicon oxide film measured at the end opposite to the direction from T _i .

In addition, the silicon nitride film etch composition according to an aspect may have a silicon nitride film etch rate of 50% or more for a vertical depth according to Equation 3 below in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers, , Specifically, it may be 70% or more, more specifically 90% to 100%.

[Equation 3]

(D _SiNx / D _NAND ) x 100

(In Equation 3 above,

D _SiNx is the vertical depth of the area where the silicon nitride film is etched relative to the wafer surface;

D _NAND is the vertical depth of the entire wafer structure.)

That is, the silicon nitride film etching composition according to one embodiment may not etch the silicon oxide film or regrow oxide at all, and may selectively etch only the silicon nitride film while minimizing oxide regrowth. Furthermore, the silicon nitride film etching composition may perfectly etch only the silicon nitride film while maintaining the thickness of the silicon oxide film up to the lowest part of the vertical NAND structure.

In addition, one aspect of the present invention provides an etching method comprising the step of selectively etching a silicon nitride film compared to a silicon oxide film using the above-described silicon nitride film etching composition, and a semiconductor device manufacturing method including the etching method.

Specifically, an etching method according to one aspect includes the steps of introducing a wafer including the above-described silicon nitride film etching composition and an etching target into a reactor; and etching the reactor by heating.

The heating may be performed at a process temperature in the range of 100 to 500 ° C or 100 to 300 ° C or 150 to 300 ° C or 160 to 200 ° C, and the appropriate temperature may be changed as needed in consideration of other processes and other factors is of course

The etching target may include a wafer on which both a silicon oxide film and a silicon nitride film are exposed; or a wafer having a laminated structure including the silicon oxide film and the silicon nitride film as unit layers; etc., and may cover all of the stacked forms in various aspects. In addition, the unit layer may include a silicon nitride layer stacked on the silicon oxide layer or a silicon oxide layer stacked on the silicon nitride layer. A specific embodiment of a wafer having a stacked structure including the silicon oxide film and the silicon nitride film as unit layers may be exemplified by a vertical stacked structure shown in FIG. 1 below.

The silicon nitride film may include a SiN film, a SiON film, a doped SiN layer, and the like, and refers to a film quality mainly used as an insulating film when forming a gate electrode, etc., but a silicon nitride film is selectively compared to a silicon oxide film. Any technical field intended for etching may be used without limitation.

In addition, the silicon oxide film is not limited as long as it is a silicon oxide film commonly used in the art, and as an example, a spin on dielectric (SOD) film, a high density plasma (HDP) film, a thermal oxide film, a borophosphate silicate (BPSG) film, Glass) film, PSG (Phospho Silicate Glass) film, BSG (Boro Silicate Glass) film, PSZ (Polysilazane) film, FSG (Fluorinated Silicate Glass) film, 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 ( At least one layer selected from an atomic layer deposition (PE) layer, a plasma enhanced oxide (PE) layer, and an O3-tetra ethyl ortho silicate (O3-TEOS) layer may be used. However, this is only a specific example, and is not limited thereto.

As long as the wafer is conventional, it may be used without limitation, and for example, silicon, quartz, glass, silicon wafer, polysilicon wafer, polymer, metal, and metal oxide may be used, but is not limited thereto. As an example of the polymer substrate, a film substrate such as polyethylene terephthalate, polycarbonate, polyimide, polyethylene naphthalate, or cycloolefin polymer may be used. , but not limited thereto. According to one aspect of the present invention, damage to a normal silicon wafer or polysilicon wafer can be minimized.

Hereinafter, the above-described implementation examples will be described in more detail through examples. However, the following examples are for illustrative purposes only and do not limit the scope of rights.

[Examples 1 to 5 and Comparative Examples 1 to 8]

85% by weight of phosphoric acid (15% by weight H ₂ O) was prepared, mixed with each component listed in Table 1, and then stirred at room temperature (25 ° C) at a rate of 500 rpm for 5 minutes to prepare each silicon nitride film etching composition. manufactured.

Example 1 Phosphoric acid (64.9% by weight) + oxalic acid (14.3% by weight) + etidronic acid (9.4% by weight) Example 2 Phosphoric acid (60.1 wt%) + oxalic acid (13.3 wt%) + N-(2-acetamido)iminodiacetic acid (16.0 wt%) Example 3 Phosphoric acid (64.9 wt%) + oxalic acid (14.3 wt%) + etidronic acid (9.4 wt%) + HF (0.0012 wt%) Example 4 Phosphoric acid (69.9% by weight) + Formic acid (7.6% by weight) + Etidronic acid (10.1% by weight) Example 5 Phosphoric acid (51.6% by weight) + Citric acid (31.9% by weight) + Etidronic acid (7.4% by weight) Comparative Example 1 Phosphoric acid (85% by weight) Comparative Example 2 Phosphoric acid (84.6% by weight) + silicic acid (0.5% by weight) Comparative Example 3 Phosphoric acid (78.7% by weight) + benzoic acid (7.4% by weight) Comparative Example 4 Phosphoric acid (69.5% by weight) + Benzoic acid (6.6% by weight) + Etidronic acid (11.7% by weight) Comparative Example 5 Phosphoric acid (71.6% by weight) + oxalic acid (15.8% by weight) Comparative Example 6 Phosphoric acid (71.6 wt%) + oxalic acid (15.8 wt%) + HF (0.0012 wt%)

<Evaluation example> Etching performance evaluation

Etching ability of the silicon nitride film etching composition prepared in Examples and Comparative Examples was evaluated by fabricating a patterned wafer having a vertical NAND structure. Specifically, a silicon nitride film (Si ₃ N ₄ ) and a silicon oxide film (SiO ₂ ) are alternately deposited 100 times on a silicon wafer by the PECVD method, and patterning is performed through dry etching after photolithography to perform silicon nitride film/silicon. A patterned wafer having a vertical NAND structure in which 100 layers of oxide films (unit layer, 1 layer) were repeatedly stacked was fabricated.

The silicon nitride film etching composition prepared in Examples and Comparative Examples and the vertical NAND structure patterned wafer were put into a quartz reactor and an etching process was performed at 160 ° C. for 20 minutes. The etched wafer was washed with deionized water after the experiment and dried using nitrogen gas (FIG. 1). After the etching experiment, the amount of the silicon nitride film etched in the horizontal direction and the thickness of the remaining silicon oxide film were measured using FE-SEM (Field Emission Scanning Electron Microscopes, model name: JEOL-7610-Plus, manufacturer: JEOL Ltd.). measured.

In addition, it is determined by the silicon nitride film etch rate (ER _Si3N4 ) and the silicon oxide film etch rate (ER _SiO2 ) obtained from the uppermost Si ₃ N ₄ /SiO ₂ layer of a vertical NAND structure in which 100 layers of silicon nitride/silicon oxide films are stacked, and their ratios. The etching selectivity (ER _Si3N4 /ER _SiO2,o ) obtained by the method of FIG. 2 is shown in Table 2 below. Specifically, the etch rate (ER _Si3N4 ) of the silicon nitride film in the horizontal direction was obtained in the vertical stacked structure of 100 layers of silicon nitride/silicon oxide film. The vertical silicon oxide film etch rate (ER _SiO2 ) was obtained from the change in . In particular, since the thickness of the outside and inside of the silicon oxide film is often different, the etching rate of the silicon oxide film at two places (external ER _SiO2,o and internal ER _SiO2,i ) is indicated respectively, and the thickness ratio between the outside and the inside (T _o /T _i ) is also indicated. The representative etching selectivity of the silicon nitride film/silicon oxide film means the ratio of the etching rate of the internal silicon nitride film in the horizontal direction to the etching rate of the external silicon oxide film (ER _Si3N4 / ER _SiO2,o ).

In addition, according to the method shown in FIG. 3 , the silicon nitride film etch rate (ED _Si3N4 ) with respect to the depth in the vertical direction of the silicon nitride film/silicon oxide film 100-layer vertical stacking structure was calculated and shown in Table 2 below.

division ED _Si3N4
(%) _ERSi3N4
(Å/min) ER _SiO2,o
(Å/min) ER _SiO2,i
(Å/min) silicon oxide film
Internal/external thickness ratio
(T- _o /T _i ) representative
Etch selectivity
(ER _Si3N4 /ER _SiO2,o ) Example 1 100 95 0 0 One ∞ Example 2 100 97 0.12 0.01 0.98 808 Example 3 100 128 0.19 0 0.97 674 Example 4 100 105 -1.36 0 1.23 - Example 5 100 96 -1.28 0 1.22 - Comparative Example 1 45 109 -4.11 0 1.7 - Comparative Example 2 35 92 -6.65 0 2.14 - Comparative Example 3 38 93 -2.91 0.04 1.51 - Comparative Example 4 37 85 -3.76 0 1.64 - Comparative Example 5 100 74 0 0 One ∞

Referring to Table 2, it can be seen that the silicon nitride film etching composition according to the present invention does not etch the silicon oxide film at all, and selectively etches only the silicon nitride film while minimizing oxide regrowth. Furthermore, it was confirmed that the silicon nitride film etching composition according to the present invention can perfectly etch only the silicon nitride film while maintaining the thickness of the silicon oxide film up to the lowermost part of the vertical NAND structure repeatedly stacked up to 100 layers.

On the other hand, in the case of Comparative Example 2 in which a silicon-based compound was added to phosphoric acid, as well as in Comparative Example 3 in which benzoic acid capable of inhibiting the etching of the silicon oxide film was added, oxide regrowth was very severe, similar to Comparative Example 1, which is a phosphoric acid process. occurred, and it was confirmed that the selective etching of the silicon nitride film could not be properly implemented up to the lower end of the vertical NAND structure.

In addition, even in the case of Comparative Example 6 not containing a chelating agent, it was confirmed that the etching selectivity with respect to the silicon nitride film was lowered.

As described above, the present invention has been described with specific details and limited examples, but this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above examples, and the field to which the present invention belongs Those skilled in the art can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and it will be said that not only the claims to be described later, but also all modifications equivalent or equivalent to these claims belong to the scope of the present invention. .

Claims (14)

phosphoric acid; Carboxyl group-containing aliphatic organic acids or salts thereof; And a chelating agent, a silicon nitride film etching composition. According to claim 1,
The silicon nitride film etching composition further comprising a fluorine-based compound. According to claim 1,
The carboxyl group-containing aliphatic organic acid comprises oxalic acid, formic acid, citric acid or α-ketoglutaric acid, the silicon nitride film etching composition. According to claim 1,
The chelating agent comprises etidronic acid, aminotrimethylenephosphonic acid, N- (2-acetamido) iminodiacetic acid or N- (phosphonomethyl) iminodiacetic acid, silicon nitride film etching composition. According to claim 1,
The silicon nitride film etching composition is a silicon nitride film etching composition that does not substantially contain a silicon-based compound. According to claim 2,
50 to 85% by weight of phosphoric acid, 0.1 to 30% by weight of a carboxyl group-containing aliphatic organic acid or a salt thereof, 0.1 to 20% by weight of a chelating agent, and 0.0001 to 0.1% by weight of a fluorine-based compound, based on the total weight of the silicon nitride film etching composition , Silicon nitride film etching composition. According to claim 1,
The silicon nitride film etching composition
A silicon nitride film etching composition having an etching selectivity of 500 or more according to Equation 1 below in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers.
[Equation 1]
E _SiNx / E _SiO2
In Equation 1 above,
E _SiNx is the etch rate for the silicon nitride film;
E _SiO2 is the etching rate for the outside of the silicon oxide film. According to claim 7,
The silicon nitride film etching composition has an etch rate (Å / min) for the outside of the silicon oxide film in a vertical stack structure (NAND) wafer having a silicon oxide film and a silicon nitride film as a unit layer, a silicon nitride film etching composition. According to claim 8,
The silicon nitride film etching composition,
After etching in a NAND wafer having a silicon oxide film and a silicon nitride film as a unit layer, the silicon nitride film etching, in which the outer thickness (T _o ) compared to the inner thickness (T _i ) of the silicon oxide film satisfies Equation 2 below. composition
[Equation 2]
0.75 ≤ T _o /T _i ≤ 1.25
In Equation 2 above,
T _o is the outer thickness of the silicon oxide film;
T _i is the internal thickness of the silicon oxide film. According to claim 9,
The silicon nitride film etching composition has a silicon nitride film etch rate of 50% or more according to Equation 3 below in a NAND wafer having a silicon oxide film and a silicon nitride film as unit layers.
[Equation 3]
(D _SiNx / D _NAND ) x 100
In Equation 3 above,
D _SiNx is the vertical depth of the area where the silicon nitride film is etched relative to the wafer surface;
D _NAND is the vertical depth of the entire wafer structure. Using the silicon nitride film etching composition according to any one of claims 1 to 10, selectively etching the silicon nitride film compared to the silicon oxide film; Etching method comprising the. According to claim 11,
An object to be etched by the silicon nitride film etching composition may include a wafer on which both the silicon oxide film and the silicon nitride film are exposed; Or, a wafer of a vertical stacked structure including the silicon oxide film and the silicon nitride film as a unit layer, an etching method. According to claim 12,
The etching method is for high temperature etching of 100 ℃ or more, etching method. A method of manufacturing a semiconductor device comprising an etching process performed using the silicon nitride film etching composition according to any one of claims 1 to 10.

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