KR102216352B1 - Composision for etching, method for etching and semiconductor device - Google Patents

Abstract

The etching composition according to an embodiment of the present invention includes 10 to 40% by weight of a fluorine-containing compound, 0.05 to 5% by weight of a thio-based compound, and the remaining amount of a solvent.
The etching composition may etch an insulating film with excellent performance without causing galvanic corrosion on a semiconductor wafer or the like.

Description

Etching composition, etching method, and semiconductor device TECHNICAL FIELD [COMPOSISION FOR ETCHING, METHOD FOR ETCHING AND SEMICONDUCTOR DEVICE}

The present invention relates to an etching composition, an etching method, and a semiconductor device, and more particularly, to an etching composition that does not cause galvanic corrosion, an etching method using the same, and a semiconductor device manufactured by the etching method.

In a semiconductor device manufacturing process, a silicon oxide film (SiO ₂ ) is used for electrical insulation between conductive layers. The silicon oxide film is typically formed on a semiconductor wafer by a deposition or growth method. And the silicon oxide film is patterned by removing it by a dry or wet method.

In order to remove the silicon oxide layer by a wet method, a wet etching composition is used. Currently, BOE (Buffered Oxide Etchant) solution is widely used as such a wet etching composition.

However, fluorine in a commonly used BOE solution causes corrosion of metal or metal silicide wiring of a semiconductor wafer during etching of the silicon oxide film. In particular, when two different metals or more metals are exposed to the etching composition in a paired state, one metal is preferentially corroded and the other metal experiences galvanic corrosion, which is protected from corrosion. Metal silicides including cobalt silicide in the patterned wafer have a negative potential compared to other conventional metals in the BOE, and thus act as an active metal in the galvanic series and are more sensitive to corrosion. Therefore, there is a need for research on an etching composition having an excellent etching function without damaging a semiconductor wafer.

An object of the present invention is to provide an etching composition that does not cause galvanic corrosion.

Another object of the present invention is to provide an etching method using the etching composition.

Another object of the present invention is to provide a semiconductor device manufactured by the above etching method.

In order to achieve the above object, the etching composition according to an embodiment of the present invention includes 10 to 40% by weight of a fluorine-containing compound, 0.05 to 5% by weight of a thio-based compound, and the remaining amount of a solvent.

The fluorine-containing compound includes hydrogen fluoride (HF), sodium fluoride (NaF), acidic sodium fluoride (NaHF ₂ ), ammonium fluoride (NH ₄ F), acidic ammonium fluoride (NH ₄ HF ₂ ), ammonium borofluoride (NH ₄ BF ₄ ), fluorosilicic acid (H ₂ SiF ₆ ), potassium fluoride (KF), acidic potassium fluoride (KHF ₂ ), aluminum fluoride (AlF ₃ ), boronic acid fluoride (HBF ₄ ), lithium fluoride (LiF ₄ ), boron Potassium fluoride (KBF ₄ ), calcium fluoride (CaF ₂ ), or a mixture thereof may be exemplified.

The thio-based compound may be a thio-based organic compound. Such thio-based organic compounds include 1,3-propanedithiol, 2,2'-(ethylenedioxy) diethanthiol, 2,3-butanedithiol, 1-mercapto-2-propanol, and 3-mercapto Propionic acid, 4-mercapto-1-butanol, 6-mercaptohexanoic acid, 11-mercaptoundecanoic acid, 12-mercaptododecanoic acid, 16-mercaptohexadecanoic acid, β-thiodiglycol and mercapto One or more selected from the group consisting of acetic acid may be exemplified.

An etching method according to another embodiment of the present invention includes the step of etching an insulating layer using the etching composition.

A semiconductor device according to another embodiment of the present invention is manufactured by the above etching method.

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

The etching composition according to an embodiment of the present invention includes 10 to 40% by weight of a fluorine-containing compound, 0.05 to 5% by weight of a thio-based compound, and the remaining solvent.

The fluorine-containing compound is a compound capable of etching an insulating layer or a metal layer, and the etching performance may be controlled by controlling the type and/or content of the compound.

The fluorine-containing compound includes hydrogen fluoride (HF), sodium fluoride (NaF), acidic sodium fluoride (NaHF ₂ ), ammonium fluoride (NH ₄ F), acidic ammonium fluoride (NH ₄ HF ₂ ), ammonium borofluoride (NH ₄ BF ₄ ), fluorosilicic acid (H ₂ SiF ₆ ), potassium fluoride (KF), acidic potassium fluoride (KHF ₂ ), aluminum fluoride (AlF ₃ ), boronic acid fluoride (HBF ₄ ), lithium fluoride (LiF ₄ ), boron Potassium fluoride (KBF ₄ ), calcium fluoride (CaF ₂ ), or a mixture thereof may be exemplified.

The fluorine-containing compound may be used in 10 to 40% by weight, 10 to 35% by weight, 10 to 30% by weight, 10 to 25% by weight, or 12 to 25% by weight based on the total weight of the total etching composition. When the fluorine-containing compound is used in the above range, an etching composition capable of etching an insulating film or the like at an appropriate rate may be provided.

In one example, a combination of hydrogen fluoride and ammonium fluoride or a combination of fluorosilicic acid and ammonium fluoride may be employed as the fluorine-containing compound. When a combination of hydrogen fluoride and ammonium fluoride is employed above, hydrogen fluoride may be used in an amount of 1 to 20% by weight, and ammonium fluoride may be used in an amount of 10 to 20% by weight based on the total weight of the etching composition. And when a combination of fluorosilicic acid and ammonium fluoride is employed, fluorosilicic acid may be used in an amount of 1 to 20% by weight based on the total weight of the etching composition, and ammonium fluoride may be used in an amount of 10 to 20% by weight. When the above-described component is used as a fluorine-containing compound in the above-described amount, it is possible to provide an etching composition having excellent etching performance while preventing galvanic corrosion caused by the etching composition as much as possible.

The thio-based compound is a compound containing a sulfur element, and is a compound containing a mercapto group (-SH) or a substituted mercapto group. The substituted mercapto group is wherein the hydrogen of the mercapto group is, for example, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, or a carboxyalkyl group having 1 to 20 carbon atoms. Can be.

The thio-based compound may be a thio-based organic compound containing carbon. The thio-based organic compound can minimize galvanic corrosion of semiconductor wafers, etc. caused by fluorine without affecting the etching performance of the etching composition. Thio-based organic compounds that can exhibit these performances include 1,3-propanedithiol, 2,2'-(ethylenedioxy) diethanethiol (2,2'-(ethylenedioxy)diethanethiol). ), 2,3-butanedithiol, 1-mercapto-2-proanol, 3-mercaptopropionic acid, 4-mer Capto-1-butanol (4-mercapto-1-butanol), 6-mercaptohexanoic acid, 11-mercaptoundecanoic acid (11-mercaptoundecanoic acid), 12-mercaptododecanoic acid ( One or more selected from the group consisting of 12-mercaptododecanoic acid), 16-mercaptohexadecanoic acid, β-thiodiglycol, and mercaptoacetic acid may be exemplified. have.

The thio-based compound may be used in an amount of 0.05 to 5% by weight, 0.1 to 5% by weight, or 0.1 to 3% by weight based on the total etching composition. If a thio-based compound is blended in the etching composition below the above range, the galvanic corrosion prevention effect may be insignificant, and if a thio-based compound is used outside the above range, it is not dissolved in the etching composition or is not suitable for the etching function of the etching composition. It may lead to an unpredictable pH change, and it is impossible to economically produce an etching composition by using an expensive thio-based compound in excess.

The etching composition may further include a solvent. The solvent may be included in an amount excluding the above-described components in the entire etching composition.

The solvent may be any one selected from the group consisting of water, alcohol, glycol ether, ether, ester, ketone, carbonate, amide, and combinations thereof.

As the alcohol, methanol, ethanol, isopropanol, n-propanol, n-hexanol, n-octanol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, tetrahydrofurfuryl alcohol , Glycerin, and the like, and examples of the glycol ether include propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether propionate, ethylene glycol Monobutyl ether, ethylene glycol monobutyl ether acetate, and the like, and examples of the ether include diethyl ether, tetrahydrofuran, and 1,4-dioxane, and examples of the ester include ethyl lactate, 3-methyl Methyl oxypropionate, methyl acetate, ethyl acetate, γ-butyrolactone, and the like. Examples of the ketone include acetone, methyl ethyl ketone, and the like, and examples of the carbonate include dimethyl carbonate, diethyl carbonate, ethylene carbonate, Propylene carbonate, etc. are mentioned, and N,N-dimethyl acetamide, N,N-dimethyl formamide, etc. are mentioned as an amide. In one example, the solvent may be water.

The etching composition may further include a surfactant as necessary to remove the etched residue. As the surfactant, anionic surfactant, cationic surfactant, or nonionic surfactant may be used. Examples of the cationic surfactant include amines such as C ₈ H ₁₇ NH ₂ , and examples of the anionic surfactant include hydrocarbon-based carboxylic acids such as C ₈ H ₁₇ COOH, and hydrocarbon-based such as C ₈ H ₁₇ SO ₃ H. Fluorine-based carboxylic acids such as sulfonic acid and H(CF ₂ ) ₆ COOH, and other nonionic surfactants include ethers such as polyoxyalkylene alkyl ether. The surfactant may be included in an amount of 0.01 to 1% by weight based on the total etching composition.

The etching composition may further add an alkaline compound or an acid other than the hydrogen fluoride as necessary for pH adjustment. The alkaline compound may be ammonia, amine or tetraalkyl ammonium hydroxide, or a nitrogen-containing heterocyclic compound. Examples of acids other than hydrogen fluoride include inorganic acids such as silicic acid, phosphoric acid, boric acid, hydrochloric acid, sulfuric acid, nitric acid or perchloric acid.

In addition to the above-described components, the etching composition may further include additives commonly used in the art.

An etching method according to another embodiment of the present invention includes the step of etching an insulating layer using the etching composition. The insulating film may be a silicon oxide film, a silicon nitride film, a polysilicon film, or a mixture thereof. In one example, the etching composition has a higher etching rate for the silicon oxide layer than other insulating layers and has excellent etching performance, and thus the insulating layer may be silicon oxide. However, the insulating film of the present invention is not limited thereto.

As the etching composition contains an appropriate thio-based compound in an appropriate amount, it is possible to provide an etched film or semiconductor device of excellent quality without damaging the substrate on which the insulating film is formed.

The etching method may be performed by, for example, forming an insulating layer on a substrate, applying the etching composition to the insulating layer, and removing the etching composition when etching is completed.

The substrate may be, for example, a semiconductor wafer, but the present invention is not limited thereto, and any substrate commonly used in the technical field of the present invention may be used.

A method of adding the etching composition to the insulating layer is not particularly limited as long as it is a method capable of removing the insulating layer. For example, the method may be a method such as coating, dipping, spraying or spraying. In particular, since there is little change in composition over time and little change in etching rate, a method of immersion (batch type device) or a method of spraying (sheet wafer type device) can be used.

The application temperature of the etching composition may be 15 to 40°C, preferably 20 to 30°C. The insulating layer may be etched by applying the etching composition to the substrate within the temperature range. The application time of the etching composition varies depending on the thickness of the insulating layer, but may generally be 30 seconds to 3 minutes.

After the etching, the etching composition may be removed with ultrapure water or the like. In addition, the etched insulating layer may be dried.

In addition to the above-described process, the etching method may further include a process commonly employed in the art.

A semiconductor device according to another embodiment of the present invention is manufactured by the above etching method. The kind of the semiconductor device is not particularly limited in the present invention.

The etching composition according to an exemplary embodiment of the present invention may etch an insulating film with excellent performance without causing galvanic corrosion on a semiconductor wafer or the like.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[ Manufacturing example : Etching Preparation of the composition]

Etching compositions of Examples and Comparative Examples were prepared while varying the formulation as described in Table 1 below.

Hydrogen fluoride Fluorosilicic acid Dissension
ammonium Thio compound Comparison compound water Kinds content Kinds content Example 1 2 - 15 1,3-propanedithiol 2 - - 81 Example 2 2 - 15 1-mercapto-2-proanol 2 - - 81 Example 3 2 - 15 3-mercaptopropionic acid 2 - - 81 Example 4 - 5 15 3-mercaptopropionic acid 2 - - 78 Comparative Example 1 2 - 15 - - - - 83 Comparative Example 2 2 - 15 - - N-(2-Acetamido) iminodiacetic acid 2 81 Comparative Example 3 2 - 15 - - Ascobic acid 2 81 Comparative Example 4 2 - 15 - - Dimethylethanolamine 2 81 Comparative Example 5 - 5 15 - - - - 80

(Unit: parts by weight)

[ Experimental example : Etching Evaluation of the performance of the composition]

The degree of galvanic corrosion caused by the prepared etching composition and the etching performance of various films of the prepared etching composition were evaluated, and the results are shown in Table 2 below.

Depending on the time of exposure to the etching composition
Corrosion depth (㎛) Etch rate (Å/min) 1min 5min 10min 30min 1hr 24h SiO ₂ Si ₃ N ₄ Poly Si W Example 1 0 1.5 3.0 8.3 15.0 43.0 480±10 7.0±0.5 Less than 0.1 Less than 0.1 Example 2 0 0.5 1.1 3.5 6.1 18.0 500±10 7.1±0.5 Less than 0.1 Less than 0.1 Example 3 0 0 0.5 2.0 3.8 10.5 520±10 7.2±0.5 Less than 0.1 Less than 0.1 Example 4 0 0 0 0 0 0 510±10 7.1±0.5 Less than 0.1 Less than 0.1 Comparative Example 1 1.0 6 13 50.2 More than 70 More than 70 480±10 7.0±0.5 Less than 0.1 Less than 0.1 Comparative Example 2 0.9 5 10.9 49.5 More than 70 More than 70 490±10 7.0±0.5 Less than 0.1 Less than 0.1 Comparative Example 3 1.3 7 13.2 48.5 More than 70 More than 70 490±10 7.0±0.5 Less than 0.1 Less than 0.1 Comparative Example 4 1.0 6 10.2 49.6 More than 70 More than 70 490±10 7.0±0.5 Less than 0.1 Less than 0.2 Comparative Example 5 1.1 6 10.9 41.2 More than 70 More than 70 500±10 7.1±0.5 Less than 0.1 Less than 0.1

(1) Evaluation of the degree of galvanic corrosion caused by the etching composition

In order to evaluate the degree of galvanic corrosion caused by the prepared etching composition, as shown in Figure 1 below, 8 simulated pattern wafers in which Metal 1, Metal 2, and cobalt silicide films were sequentially stacked were prepared, and Examples 1 to 4 and Comparative Example 1 It was added to the etching composition of 5 to.

[Picture 1]

And the degree of galvanic corrosion of the simulated pattern wafer contained in each etching composition was measured over time. Galvanic corrosion of the replica pattern wafer occurred preferentially in the cobalt silicide film as shown in Fig. 1 above. In order to quantify the degree of galvanic corrosion, the corrosion depth was measured as shown in Fig. 1, and the corrosion depth measured over time is shown in Table 2.

(2) Etching performance evaluation of the etching composition

In order to evaluate the etching performance of the prepared etching composition for various layers, the etching rates for various layers were measured, and the results are shown in Table 2.

Specifically, the prepared etching composition was added to a beaker. Subsequently, semiconductor wafers in which a silicon oxide film (SiO ₂ ), a silicon nitride film (Si ₃ N ₄ ), tungsten (W), and polysilicon (Poly Si) are formed at a temperature of about 25° C. were prepared in Examples 1 to 4 and Comparative Examples 1 to It was immersed in the etching composition of 5. In addition, the etching rate was measured from the change in the thickness of the film measured before/after immersion of the semiconductor wafer.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also present. It belongs to the scope of rights of

Claims (6)

10 to 40% by weight of a fluorine-containing compound, 0.05 to 5% by weight of a thio-based organic compound, and the remaining amount of a solvent,
The thio-based organic compound is 1,3-propanedithiol, 2,2'-(ethylenedioxy) diethanthiol, 2,3-butanedithiol, 3-mercaptopropionic acid, 4-mercapto-1-butanol , 6-mercaptohexanoic acid, 11-mercaptoundecanoic acid, 12-mercaptododecanoic acid, 16-mercaptohexadecanoic acid, and at least one selected from the group consisting of β-thiodiglycol.
The method of claim 1,
The fluorine-containing compound is hydrogen fluoride (HF), sodium fluoride (NaF), acidic sodium fluoride (NaHF ₂ ), ammonium fluoride (NH ₄ F), acidic ammonium fluoride (NH ₄ HF ₂ ), ammonium borofluoride (NH ₄ BF) ₄ ), fluorosilicic acid (H ₂ SiF ₆ ), potassium fluoride (KF), acidic potassium fluoride (KHF ₂ ), aluminum fluoride (AlF ₃ ), boronic acid fluoride (HBF ₄ ), lithium fluoride (LiF ₄ ), borofluoride Potassium (KBF ₄ ), calcium fluoride (CaF ₂ ), or a mixture thereof, the etching composition.
delete delete An etching method comprising the step of etching the insulating layer using the etching composition according to claim 1.
A semiconductor device manufactured by the etching method according to claim 5.