KR102668708B1 - Etching composition for etching a polysilicon and method for manufacturing a semiconductor device - Google Patents

Abstract

The present invention provides a polysilicon etchant composition containing quaternary alkylammonium hydroxide, a fluorine-based surfactant, a water-soluble amine compound, and water, and a method of manufacturing a semiconductor device using the same.

Description

Polysilicon etchant composition and method for manufacturing a semiconductor device {ETCHING COMPOSITION FOR ETCHING A POLYSILICON AND METHOD FOR MANUFACTURING A SEMICONDUCTOR DEVICE}

The present invention relates to a polysilicon etchant composition, and more specifically, to a polysilicon etchant composition containing quaternary alkylammonium hydroxide, a fluorine-based surfactant, a water-soluble amine compound and water, and a method of manufacturing a semiconductor device using the same.

Semiconductor devices are required to operate at high speeds and have large storage capabilities. In response to these demands, manufacturing technology for semiconductor devices is being developed to improve integration, reliability, and response speed.

In the above-described semiconductor device, polysilicon is a material that forms gate electrodes, capacitor electrodes, plugs, etch masks, etc., and is used for a wide variety of purposes. For this purpose, in addition to methods of forming a film using polysilicon, various methods of removing the formed polysilicon film have been developed.

Methods for removing the polysilicon film can be broadly divided into a dry etching process and a wet etching process. The wet etching process is a method of etching using a chemical etching solution, and the etching process is performed by immersing the object to be removed in the etching solution.

As a conventional polysilicon etchant, Korean Patent Publication No. 10-2011-0044214 uses (A) tetramethylammonium hydroxide, (B) hydroxyl amine, and (C) carbon dioxide (CO ₂ ) and/or tetramethylammonium carbonate. A silicon etching solution is disclosed, which is an alkaline aqueous solution containing pH 13 or higher.

In addition, Republic of Korea Patent Publication No. 10-2013-0007419 discloses a silicon etching solution containing a combination of ammonia and at least one specific basic compound selected from the group consisting of hydroxylamine compounds, basic organic compounds, and metal-containing basic compounds. It is starting.

However, since the above compositions require etching at high temperatures, the etchant components change rapidly due to volatilization and decomposition of the etchant components, resulting in large changes in the etching rate. They also have the disadvantage of not being able to secure desirable surface roughness due to the excessive etching rate. .

Republic of Korea Patent Publication No. 10-2011-0044214 Republic of Korea Patent Publication No. 10-2013-0007419

The present invention was devised to solve the problems of the prior art,

The purpose is to provide a polysilicon etchant composition that provides excellent etching speed even when etching is performed at room temperature and allows the etched polysilicon film to have excellent surface roughness.

In addition, the purpose of the present invention is to provide a polysilicon etchant composition that can uniformly remove the film material at a high speed even when removing only a certain thickness of the polysilicon film, thereby providing a film with uniform and excellent surface roughness.

Additionally, the present invention aims to provide an efficient method of manufacturing a semiconductor device using the polysilicon etchant composition.

In order to achieve the above object, the present invention,

A polysilicon etchant composition comprising a quaternary alkylammonium hydroxide, a fluorine-based surfactant, a water-soluble amine compound, and water is provided.

The polysilicon etchant composition may include 0.1 to 30% by weight of quaternary alkylammonium hydroxide, 0.001 to 5% by weight of a fluorine-based surfactant, 0.1 to 20% by weight of a water-soluble amine compound, and the remaining amount of water based on the total weight of the composition.

In addition, the present invention

A method of manufacturing a semiconductor device is provided, comprising the step of etching a polysilicon film using the polysilicon etchant composition of the present invention.

The polysilicon etchant composition of the present invention provides excellent etching speed even when etching is performed at room temperature, and provides the effect of allowing the etched polysilicon film to have excellent surface roughness.

In addition, the polysilicon etchant composition of the present invention removes the film uniformly at a high rate even when only a certain thickness of the polysilicon film is removed, thereby providing a film with uniformity and excellent surface roughness.

In addition, the polysilicon etchant composition of the present invention can improve the quality and productivity of semiconductor devices by increasing process reliability for subsequent processes based on the above effects.

Additionally, the present invention provides an efficient method of manufacturing high-quality semiconductor devices by using the polysilicon etchant composition.

Hereinafter, the present invention will be described in more detail.

The present invention,

It relates to a polysilicon etchant composition containing a quaternary alkylammonium hydroxide, a fluorine-based surfactant, a water-soluble amine compound, and water.

Based on the total weight of the polysilicon etchant composition, it may include 0.1 to 30% by weight of quaternary alkylammonium hydroxide, 0.001 to 5% by weight of fluorine-based surfactant, 0.1 to 20% by weight of water-soluble amine compound, and the remaining amount of water.

Below, the components that make up the etchant composition will be described in detail.

(A) Class 4 Alkylammonium hydroxide

The quaternary alkylammonium hydroxide included in the etchant composition of the present invention may be represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently an alkyl group having 1 to 4 carbon atoms.

Quaternary alkylammonium hydroxides represented by the above formula (1) include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and trimethylethylammonium hydroxide, and tetramethylammonium hydroxide is preferred. (hereinafter also referred to as 'TMAH') can be used.

The quaternary alkylammonium hydroxide may be included in an amount of preferably 0.1 to 30% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.5 to 10% by weight, based on the total weight of the composition. Based on the above-mentioned standards, if the content is less than 0.1% by weight, the problem of slowing down the etching speed of polysilicon may occur, and if it exceeds 30% by weight, the effect of increasing the etching speed due to an increase in content will not appear, and uneconomical problems may occur. There are concerns.

(B) Fluorine-based surfactant

The fluorine-based surfactant included in the etchant composition of the present invention refers to a hydrocarbon-based surfactant containing a perfluoroalkyl group in the main chain or side chain of a compound containing a hydrophilic group and a hydrophobic group. In particular, one in which all of the hydrogen bonded to the carbon contained in the hydrophobic group is replaced with fluorine can be more preferably used.

The fluorine-based surfactant includes anionic fluorine-based surfactants including perfluoroalkyl carboxylate, perfluoroalkyl sulfate, and perfluoroalkyl phosphate; Cationic fluorine surfactants including perfluoroalkyl amine salts and perfluoroalkyl quaternary ammonium salts; Zwitterionic fluorinated surfactants including perfluoroalkyl carboxybetaine and perfluoroalkyl sulfobetaine; and nonionic fluorinated surfactants such as perfluoroalkyl polyoxyethylene and perfluoroalkyl ester. These may be used alone or in combination of two or more. In particular, it may be preferable to use at least one selected from the group consisting of perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, and perfluoroalkyl polyoxyethylene.

In the above, 'perfluoroalkyl' refers to a C1-C10 straight-chain or branched-chain alkyl group in which all hydrogen bonded to carbon atoms are replaced with fluorine.

The fluorine-based surfactant may be included in an amount of preferably 0.001 to 5% by weight, more preferably 0.005 to 1% by weight, and even more preferably 0.01 to 0.5% by weight, based on the total weight of the composition. If the fluorine-based surfactant is included in less than 0.001% by weight based on the above standard, the effect of lowering the surface tension of the silicon surface may be minimal, which may lead to a problem of deterioration of the uniform etching effect. If it exceeds 5% by weight, the content may increase. There is no increase in the effect of lowering the surface tension, and it may be economically undesirable.

(C) Water soluble amine compound

The water-soluble amine compound included in the composition of the present invention serves to improve the etching performance of polysilicon by increasing the basicity of the composition.

The water-soluble amine compounds include methylamine, ethylamine, monoethanolamine (MEA), monoisopropanolamine (MIPA), butanolamine (BA), 1,2-propanediamine and 1,3-propanediamine, diglycolamine, water-soluble primary amines such as ethylenediamine;

Water-soluble secondary substances such as diethylamine, diisopropylamine, dibutylamine, diethanolamine (DEA), monomethylethanolamine (MMEA), aminoethylethanolamine, diethylenetriamine, dihexylenetriamine, and morpholine. amine; and

Water-soluble tertiary amines such as methyldiethanolamine, trimethylamine, triethylamine, triisopropanolamine, and tributylamine may be included, but are not limited thereto.

In particular, it may be more preferable to include at least one selected from the group consisting of monoethanolamine, diethylenetriamine, ethylenediamine, diglycolamine, and methyldiethanolamine.

The water-soluble amine compound may be included in an amount of preferably 0.1 to 20% by weight, more preferably 0.1 to 5% by weight, based on the total weight of the composition. Based on the above criteria, if the content is less than 0.1% by weight, there may be a problem that the polysilicon etching effect becomes insignificant, and if it exceeds 20% by weight, the polysilicon etching performance may deteriorate and the process time may be prolonged.

(D) water

The water included in the etchant composition of the present invention is not particularly limited, but deionized water is preferably used. More preferably, it is good to use deionized water with a water resistivity value of 18 MΩ/cm or more, which indicates the degree to which ions have been removed from the water.

Water may be included in the remaining amount so that the total weight of the composition is 100% by weight.

The etchant composition of the present invention may further include conventional additives such as antioxidants and corrosion inhibitors in addition to the ingredients described above.

The antioxidant serves to ensure smooth etching of the polysilicon film by capturing dissolved oxygen present inside the etchant. The antioxidants include hydroxylamine-based compounds such as hydroxylamine, dimethylhydroxylamine, diethylhydroxylamine, and isopropylhydroxylamine; Carbohydrazide, Ascorbic acid, 4-Methyl-1-aminopiperazine, 1,3-dimethyl-5-pyrazolone (1,3-dimethyl -5-pyrazolone, Hydroquinone, Methylethylketoxime, 1,3-dimethyl-5-pyrazolone, Urazole (1,2) , 4-triazolidine-3,5-dione), etc., but is not limited thereto.

The antioxidant may preferably be included in an amount of 0.1 to 20% by weight based on the total weight of the composition.

The corrosion inhibitor is not particularly limited as long as it is commonly used in the field.

In addition, the etchant composition of the present invention can be manufactured by a commonly known method, and it may be desirable to have a purity for semiconductor processing.

The polysilicon etchant composition is used in a polysilicon film etching process, and the present invention provides a method of manufacturing a semiconductor device including a process of etching a polysilicon film using the composition. At this time, the polysilicon film etching method may be performed by a method commonly known in the art. For example, etching may be performed using immersion, spraying, or immersion and spraying in a batch type etching device or a single type etching device. In this case, the temperature may be 20 to 70°C, preferably 20 to 50°C, and if the etching equipment is operated in a clean room environment where the temperature is kept constant, the polysilicon film can be etched even at room temperature without additional heating. It is desirable to have In other words, it is desirable to prevent uneven etching that occurs due to temperature deviation and its effects when using a heating device.

The soaking and spraying time can usually be 30 seconds to 10 minutes, preferably 1 to 5 minutes. However, these conditions are not strictly applied, and easy or suitable conditions may be selected by those skilled in the art.

Hereinafter, the present invention will be described in more detail using examples and comparative examples. However, the following examples and comparative examples are for illustrating the present invention, and the present invention is not limited by the following examples and comparative examples, and may be modified and changed in various ways. The scope of the present invention will be determined by the technical spirit of the claims described later.

< Example and Comparative example > etchant Preparation of composition

Examples 1 to 14 with the composition and content shown in Table 1 below And the etchant compositions of Comparative Examples 1 to 5 were prepared.

(Unit: weight%) Furtherance Quaternary alkyl ammonium hydroxide Fluorine-based surfactant water-soluble amine compounds etc water TMAH ^{1 )} TEAH ^{2 )} ETMAH ^{3 )} PFAS ^{4 )} PFAC ^{5 )} PFEO ^{6 )} MEA DETA MDEA Example 1 5 - - 0.3 - - One - - remaining amount Example 2 7 - - - 0.5 - - One - remaining amount Example 3 10 - - - - 0.7 - - One remaining amount Example 4 - 2 - 0.2 - - - One - remaining amount Example 5 - 4 - - 0.1 - - - 0.5 remaining amount Example 6 - 6 - - - 0.1 - - 0.5 remaining amount Example 7 - - 2 0.1 - - One - - remaining amount Example 8 - - 4 - 0.2 - - One - remaining amount Example 9 - - 6 - - 0.2 - - One remaining amount Example 10 3 0.001 2 remaining amount Example 11 10 5 0.5 remaining amount Example 12 0.2 0.5 15 remaining amount Example 13 2 0.03 0.2 DEHA ^{10 )} 0.2 remaining amount Example 14 0.4 6 One remaining amount Comparative Example 1 - - - 0.2 - - - 5 - remaining amount Comparative Example 2 0.5 - - - - - 2 - - remaining amount Comparative Example 3 - - 3 - - 0.5 - - - remaining amount Comparative Example 4 15 - - - - - 10 - - HA ¹¹⁾ 5 remaining amount Comparative Example 5 15 - - - - - - - - NH ₄ OH ^{12 )} 5 remaining amount 1) TMAH: tetramethylammonium hydroxide
2) TEAH: tetraethylammonium hydroxide
3) ETMAH: Trimethylethylammonium hydroxide
4) PFAS: perfluorobutylsulfate
5) PFAC: perfluorobutylcarboxylate
6) PFEO: perfluorohexylpolyoxyethylene
7) MEA: monoethanolamine
8) DETA: diethylenetriamine
9) MDEA: methyldiethanolamine
10) DEHA: diethylhydroxylamine
11) HA: hydroxylamine
12) NH ₄ OH: ammonium hydroxide

< Test example > Etching characteristics evaluation

Test example One. in polysilicon About etching speed rating

A specimen was prepared by cutting a wafer in which polysilicon was deposited to a thickness of 150 Å on a silicon wafer and cutting it to a size of 2 x 2 cm. The specimen was immersed in a constant temperature bath at 25°C containing the etchant compositions of Examples 1 to 14 and Comparative Examples 1 to 5 for 1 minute.

Next, take out the specimen, wash it with water, dry it with nitrogen, measure the film thickness of the polysilicon using an Elipsometer (FE5000S; manufactured by Ostuka), and determine the etch rate of the polysilicon film based on each film thickness change value. Calculated. At this time, the etch rate was evaluated based on the following criteria, and the results are shown in Table 2 below.

<Evaluation criteria>

◎: Etching speed 80 Å/min or more

○: Etching rate less than 40 to 80 Å/min

△: Etching rate less than 40 Å/min

X: Not etched

Test example 2. of polysilicon surface roughness evaluation

For the specimens used to evaluate the etching speed, changes in surface roughness were analyzed using an Atomic Force Microscope (AFM). At this time, the evaluation criteria are as follows, and the results are shown in Table 2 below.

<Evaluation criteria>

◎: RMS less than 10 Å

○: RMS less than 10 to 15 Å

△: RMS less than 15 to 20 Å

X: RMS 20 Å or more

As can be seen from the results in Table 2, it was confirmed that Examples 1 to 14, which are the etchant compositions of the present invention, exhibited excellent properties in both the etching rate and surface roughness evaluation of polysilicon.

On the other hand, it was confirmed that Comparative Examples 1 to 5, which did not contain any of the components of the composition of the present invention, showed poor results in one or more evaluations of etching rate and surface roughness.

Claims (8)

Contains quaternary alkylammonium hydroxide, fluorine-based surfactant, water-soluble amine compound and water,
The water-soluble amine compounds include methylamine, ethylamine, monoethanolamine (MEA), monoisopropanolamine (MIPA), butanolamine (BA), 1,2-propanediamine, 1,3-propanediamine, diglycolamine, and ethylene. Diamine, diethylamine, diisopropylamine, dibutylamine, diethanolamine (DEA), monomethylethanolamine (MMEA), aminoethylethanolamine, diethylenetriamine, dihexylenetriamine, morpholine, methyldiamine A polysilicon etchant composition comprising at least one selected from the group consisting of ethanolamine, trimethylamine, triethylamine, triisopropanolamine, and tributylamine. The method of claim 1, with respect to the total weight of the composition,
0.1 to 30% by weight of quaternary alkylammonium hydroxide,
0.001 to 5% by weight of fluorine-based surfactant,
0.1 to 20% by weight of a water-soluble amine compound, and
A polysilicon etchant composition comprising a residual amount of water. In claim 1,
A polysilicon etchant composition, characterized in that the quaternary alkylammonium hydroxide is a compound represented by the following formula (1):
[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently an alkyl group having 1 to 4 carbon atoms. In claim 1,
A polysilicon etchant composition, wherein the fluorinated surfactant is at least one selected from the group consisting of anionic fluorinated surfactants, cationic fluorinated surfactants, amphoteric ionic fluorinated surfactants, and nonionic fluorinated surfactants. In claim 1,
The fluorinated surfactants include perfluoroalkyl carboxylate, perfluoroalkyl sulfate, perfluoroalkyl phosphate, perfluoroalkyl amine salt, perfluoroalkyl quaternary ammonium salt, perfluoroalkyl carboxybetaine, perfluoroalkyl sulfobetaine, and perfluoroalkyl amine salt. A polysilicon etchant composition, characterized in that it is at least one selected from the group consisting of alkyl polyoxyethylene and perfluorinated alkyl ester. delete In claim 1,
A polysilicon etchant composition, characterized in that the composition further includes an antioxidant. A method of manufacturing a semiconductor device comprising the step of etching a polysilicon film using the polysilicon etchant composition of any one of claims 1 to 5 and 7.