KR102484988B1 - Composition for etching and manufacturing method of semiconductor device using the same - Google Patents

Abstract

It relates to an etching composition comprising an amino-siloxane compound represented by Formula 1 and a solvent. The etching composition of the present invention can selectively remove a nitride film while minimizing the etching rate of an oxide film, and adversely affects device characteristics. The effect of suppressing particle generation is excellent.
[Formula 1]

Description

Composition for etching and method for manufacturing a semiconductor device using the same

The present invention relates to an etching composition, particularly a high-selectivity etching composition capable of selectively removing a nitride film while minimizing an etching rate of an oxide film, and a method for manufacturing a semiconductor device including an etching process using the etching composition. .

In a semiconductor manufacturing process, an oxide film such as a silicon oxide film (SiO ₂ ) and a nitride film such as a silicon nitride film (SiN _x ) are representative insulating films that are used alone or alternately stacked with one or more layers. The silicon nitride film is deposited through a CVD (Chemical Vapor Deposition) process in a structure in contact with a silicon oxide film, a polysilicon film, a silicon wafer surface, etc., and is removed through dry etching and wet etching. Wet using phosphoric acid Etching is widely used.

In the wet etching process for removing the silicon nitride film, a mixture of phosphoric acid and deionized water is generally used. The deionized water is added to prevent a decrease in the etching rate and a change in etching selectivity for the oxide film, but there is a problem in that defects occur in the nitride film etching removal process even with a slight change in the amount of deionized water supplied. In addition, since phosphoric acid is a strong acid and has corrosive properties, it is difficult to handle.

Republic of Korea Patent Registration No. 1380487 (Etching Solution for Silicon Nitride Film) relates to an etching composition for selectively etching silicon nitride films, such as shallow trench isolation (STI) and gate electrode formation processes for DRAM and NAND flash memory semiconductors. A wet etching composition for selectively etching a silicon nitride film used in a manufacturing process is disclosed.

Republic of Korea Patent Publication No. 2015-0045331 (etchant composition and metal pattern manufacturing method using the same) discloses ammonium peroxydisulfate, phosphoric acid or phosphorous acid compound, chlorate-based compound, nitric acid or sulfonic acid compound, azole-based compound, fluorine compound and water containing A composition for etching is disclosed.

On the other hand, in the method of removing silicon nitride and silicon oxide films from semiconductors, research is being attempted from various angles in order to lower the etching rate of the oxide film and increase the etching rate of the nitride film, and one of them is to prepare a silicon-containing compound in an etching composition. It is used as an additive for etching compositions. However, these silicon-containing compounds have a problem in that stability and reliability of semiconductor processes are rather deteriorated by causing particles that may affect the substrate.

An object of the present invention is to provide an etching composition having a higher etching selectivity for a silicon nitride film than for a silicon oxide film in a semiconductor process.

On the other hand, the present invention is to provide an etching composition capable of reducing the etching rate of a silicon oxide film during etching of a silicon wafer and at the same time preventing aggregation of particles in the oxide film.

An object of the present invention is to provide an etching method that ensures high stability and reliability using the etching composition.

The present invention provides an etching composition comprising an amino-siloxane compound represented by Formula 1 below and a solvent.

[Formula 1]

로 이루어진 군으로부터 선택되며, 상기 R¹ 및 R²의 적어도 하나는 C1-C10 알킬아미노기이며, R³은 각각 독립적으로 수소, 할로겐, 하이드록시기, C1-C10 알킬기, C1-C10 알콕시기 및 C1-C10 미노알킬기로 이루어진 군으로부터 선택된다. In the above formula, R ¹ is each independently selected from the group consisting of hydrogen, halogen, hydroxyl group, C1-C10 alkyl group, C1-C10 alkoxy group and C1-C10 alkylamino group, R ² are each independently hydrogen, halogen, A hydroxyl group, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C1-C10 alkylamino group, and

is selected from the group consisting of, wherein at least one of R ¹ and R ² is a C1-C10 alkylamino group, and R ³ are each independently hydrogen, halogen, hydroxy group, C1-C10 alkyl group, C1-C10 alkoxy group and C1 -C10 It is selected from the group consisting of minoalkyl groups.

In one embodiment of the present invention, Formula 1 may be represented by Formula 2 below.

[Formula 2]

In the above formula,

R ¹ and R ² are the same as defined in claim 1, R ⁴ are each independently hydrogen or a C1-C10 alkyl group, at least one of R ⁴ is hydrogen, and n and m are each an integer of 1 to 10. .

In one embodiment of the present invention, Formula 1 may be represented by Formula 3 below.

[Formula 3]

In the above formula, n and m are each an integer of 1 to 5.

In one embodiment of the present invention, the etching composition may include the amino-siloxane compound represented by Chemical Formula 1 in an amount of 200 to 50000 ppm based on the total amount of the etching composition.

In one embodiment of the present invention, the composition for etching may further include 0.01 to 1% by weight of a fluorine-based compound with respect to the total composition for etching.

The present invention provides an etching composition capable of reducing the etching rate of a silicon oxide film and selectively removing a nitride film by providing a composition for etching in which the compound represented by Formula 1 is added to phosphoric acid.

The present invention suppresses the generation of particles that may be generated when the silicon-containing compound is included, thereby preventing deterioration in device characteristics due to the particles.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

"Halogen" in the present invention is fluorine, chlorine, bromine or iodine.

In the present invention, "alkyl group" means a monovalent substituent derived from a C1-C30 linear or branched saturated hydrocarbon, unless otherwise specified. Examples thereof include, but are not limited to, methyl, ethyl, propyl, isobutyl, isopropyl, tert-butyl, sec-butyl, pentyl, hexyl, and the like.

In the present invention, "alkoxy" is a monovalent substituent represented by R'O-, wherein R' means a C1-C30 alkyl group, and includes a linear, branched or cyclic structure. can do. Examples of alkyloxy include, but are not limited to, methoxy, ethoxy, n-propoxy, 1-propoxy, t-butoxy, n-butoxy, pentoxy, and the like.

In the present invention, "alkylamino group" means an amino group substituted with an alkyl group.

The present invention provides an etching composition comprising an amino-siloxane compound represented by Formula 1 below and a solvent.

[Formula 1]

로 이루어진 군으로부터 선택되며, 상기 R¹ 및 R²의 적어도 하나는 C1-C10 알킬아미노기이다. In the above formula, R ¹ is each independently selected from the group consisting of hydrogen, halogen, hydroxyl group, C1-C10 alkyl group, C1-C10 alkoxy group and C1-C10 alkylamino group, R ² are each independently hydrogen, halogen, A hydroxyl group, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C1-C10 alkylamino group, and

It is selected from the group consisting of, wherein at least one of R ¹ and R ² is a C1-C10 alkylamino group.

Each R ³ is independently selected from the group consisting of hydrogen, halogen, hydroxyl group, C1-C10 alkyl group, C1-C10 alkoxy group and C1-C10 minoalkyl group.

The amino-siloxane compound represented by Chemical Formula 1 minimizes the etching rate of the silicon oxide layer and selectively removes the silicon nitride layer by removing the silicon nitride layer faster than the etching rate of the silicon oxide layer. Furthermore, the amino-siloxane compound represented by Formula 1 prevents particles that may affect the subsequent process from being deposited or remaining on the wafer during the etching process, thereby increasing the stability and reliability of the phosphoric acid etching process used at high temperatures. can be granted.

In a preferred embodiment of the present invention, Formula 1 may be represented by Formula 2 below.

[Formula 2]

In the above formula, R ¹ and R ² are the same as described above, R ⁴ are each independently hydrogen or a C1-C10 alkyl group, at least one of R ⁴ is hydrogen, and n and m are each an integer of 1 to 10. .

In a preferred embodiment of the present invention, Formula 1 may be represented by Formula 3 below.

[Formula 3]

In the above formula, n and m are each an integer of 1 to 5.

Formula 3 may be more preferably 1,3-bis(3-aminopropyl)tetramethyldisiloxane.

In a preferred embodiment of the present invention, the amino-siloxane compound represented by Formula 1 may be included in an amount of 200 to 50000 ppm, more preferably 1000 to 20000 ppm, based on the total weight of the composition for etching.

If the content of the amino-siloxane compound represented by Formula 1 according to the present invention is too low, the silicon oxide film and the silicon nitride film are etched simultaneously, and the silicon oxide etch rate suitable for the process cannot be obtained. Conversely, When the content of the amino-siloxane compound is too high, the etching rate of the silicon nitride film and the etching rate of the silicon oxide film are reduced together to reduce the difference in selectivity, but the content of the amino-siloxane compound represented by Formula 1 according to the present invention When included in the above range, the etching rate of the silicon nitride film to the silicon oxide film can be maintained high.

When an oxide film is etched using the etching composition according to the present invention, particles generated in the conventional method of adding silicon-containing compounds, for example, silicic acid and silicate, are not formed, and the silicon nitride film can be etched with a high selectivity. .

In another embodiment of the present invention, the etching composition may additionally include a fluorine-based compound based on the total weight of the etching composition. In addition, the fluorine-based compound may be included in an amount of 0.01 to 1% by weight, preferably 0.1 to 0.5% by weight, and the fluorine-based compound may be, for example, hydrogen fluoride, ammonium fluoride, ammonium hydrogen fluoride, etc., but is not limited thereto.

Another embodiment of the present invention may provide a method of manufacturing a semiconductor device including an etching process performed using the above-described composition for etching.

As an embodiment, the etching composition of the present invention may be used after being preheated to 100 to 180 ° C. before being applied to a silicon nitride film to be etched, and when a silicon nitride film layer and a silicon oxide film layer are alternately laminated or used in combination. Even if an additional time process is performed for complete removal of the silicon nitride layer, an excellent silicon nitride layer removal effect can be obtained because there is little etching effect on the silicon oxide layer.

When etching is performed using the composition for etching of the present invention, by lowering the etching rate of the oxide film, the selectivity of the nitride film to the oxide film is high, such as 5 to 30.

Hereinafter, the present invention will be described in more detail by examples, but this is only for understanding the configuration and effects of the present invention, and is not intended to limit the scope of the present invention.

Example : for etching preparation of the composition

Example One:

An etching composition was prepared by stirring 1,3-bis(3-aminopropyl)tetramethyldisiloxane at a concentration of 2,000 ppm in an 85% phosphoric acid aqueous solution at 80 ^° C. for 3 hours.

comparative example One:

A phosphoric acid aqueous solution having a concentration of 85% was prepared as an etching composition.

comparative example 2:

A composition for etching was prepared by adding trimethylsilanol at a concentration of 2,000 ppm to an aqueous phosphoric acid solution having a concentration of 85% and stirring at 80 ^° C for 30 minutes.

trimethylsilanol

comparative example 3:

An etching composition was prepared by adding a compound represented by the formula below to a phosphoric acid aqueous solution having a concentration of 85% at a concentration of 2,000 ppm and stirring at 80 ^° C for 30 minutes.

3-(1,1,3,3,3-pentamethyldisiloxanyl)propan-1-amine

Characteristic evaluation

selectivity measurement

After heating the compositions for etching prepared in Examples and Comparative Examples 1 to 3 at 160 to 180 ° C, respectively, etching was performed on ALD SiO _x , and thin film thickness measuring equipment, an ellipsometer (NANO VIEW, SEMG-1000) The etching rate (E/R) for the oxide film was measured using . The etching rate shown in Table 1 below is an average etching rate obtained by measuring 5 times by the above method.

membranous thickness before etching thickness after etching E/R Example One ALD sio _x 503.44 497.66 5.78 comparative example One ALD sio _x 501.94 481.40 20.54 comparative example 2 ALD sio _x 502.44 486.67 15.77 comparative example 3 ALD sio _x 500.38 490.27 10.11

In Example 1, it was confirmed that the etching rate of the oxide film was significantly lower than that of Comparative Examples 1 to 3.

Trimethylsilanol of Comparative Example 2 has a low boiling point, and as the concentration of trimethylsilanol in the aqueous phosphoric acid solution rapidly decreases from the preheating process before using the etching composition, the control of the etching rate of the oxide film is possible. it became difficult

As the etching composition is heated, the silicon-containing compound of Comparative Example 3 is hydrolyzed into trimethylsilanol and (3-aminopropyl) (dimethyl)silanol, so that the etching rate of the oxide film can be controlled for the same reason as in Comparative Example 1. it became difficult

[ particle formation observation]

Etching was performed using the etching composition prepared according to Examples and Comparative Examples according to the method described above, and the size of particles generated after etching was measured using a particle size analyzer (PSA), exceeding 200 μm and 10 By measuring whether or not particles smaller than ㎛ were generated and their particle size, the results are shown in Table 2 below.

More than 200 Particles less than 200 particles Example One - <0.01 μm comparative example One 210, 310 μm 15, 87, 185 μm comparative example 2 - <0.5 μm comparative example 3 - <0.1 μm

As shown in Table 2, in the case of the etching composition including the amino-siloxane compound represented by Formula 1 according to the present invention, in Example 1, no particles exceeding 200 were found, and only particles with a diameter of less than 0.01 μm were found. By finding a small amount of this, the generation of particles is prevented compared to Comparative Examples 1 to 3, and elements that may ultimately have a negative effect on the device are removed. can confirm that it is.

Claims (8)

An etching composition comprising an amino-siloxane compound represented by Formula 2 and a solvent:
[Formula 2]

In the above formula,
R ¹ is each independently selected from the group consisting of hydrogen, halogen, hydroxyl group, C1-C10 alkyl group, C1-C10 alkoxy group and C1-C10 alkylamino group;
R ² are each independently hydrogen, halogen, a hydroxyl group, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C1-C10 alkylamino group, and

It is selected from the group consisting of
At least one of R ¹ and R ² is a C1-C10 alkylamino group,
R ³ is selected from the group consisting of hydrogen, halogen, hydroxyl group, C1-C10 alkyl group, C1-C10 alkoxy group and C1-C10 minoalkyl group;
R ⁴ are each independently hydrogen or a C1-C10 alkyl group, and at least one of R4 is hydrogen;
n and m are each an integer from 1 to 10; delete According to claim 1,
An etching composition in which Formula 2 is represented by Formula 3 below:
[Formula 3]

In the above formula,
n and m are each an integer from 1 to 5; According to claim 1,
An etching composition comprising 200 to 50000 ppm of the amino-siloxane compound represented by Formula 1 with respect to the entire composition for etching: According to claim 1,
An etching composition further comprising 0.01 to 1% by weight of a fluorine-based compound based on the total weight of the etching composition. According to claim 5,
The fluorine-based compound is any one selected from the group consisting of hydrogen fluoride, ammonium fluoride, ammonium hydrogen fluoride, and mixtures thereof, the composition for etching. A method of manufacturing a semiconductor device comprising an etching process performed using the composition for etching according to any one of claims 1 to 6. According to claim 7,
The etching process is to selectively etch the nitride film with respect to the oxide film,
A method of manufacturing a semiconductor device in which the selectivity of the nitride film to the oxide film by the etching process is 5 to 30.