JP2000056478A - Side wall removing liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a side wall removing liquid capable of easily removing the side wall at low cost and low temperature in a short time in one process without corroding a wiring material. SOLUTION: The side wall removing liquid, preferably, can use at least one kind of oxidant selected from a group comprising ozone, hydrogen peroxide, hypochlorus acid or hypochlorite, chlorus acid or chlorite, perchloric acid or perchlorate, hypobromus acid or hypobromite, bromus acid or bromite, perbromic acid or perbromite, hypoiodus acid or hypoiodite, iodus acid or iodite, and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sidewall removing liquid, and more particularly, to removing a sidewall generated during dry etching in a semiconductor manufacturing process at a low temperature in a short time. The present invention relates to a sidewall removing liquid that does not erode the wiring material.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device has been manufactured, for example, by the following steps. A metal layer such as Al serving as a wiring material is formed on an insulating layer such as SiO ₂ . A photoresist layer is formed thereon. Further, a photomask is superposed thereon and exposed. A resist pattern is formed by performing a developing process. The exposed metal layer is etched. A metal wiring pattern is obtained by removing and removing the resist pattern.

In recent years, in order to increase the density of integrated circuits, it has become necessary to form finer patterns. Conventionally, chemical etching using chemicals has been performed in etching, but in order to form finer patterns,
Dry etching using a halogen-based gas has been frequently used. In dry etching, sidewalls (sidewall protective films) are generated, which enables anisotropic etching. The sidewall is generated by a chemical reaction between the photoresist, a wiring material, and an etching gas during dry etching. As a result, the sidewall is a compound having a complex composition including an organic substance derived from a photoresist, an inorganic substance derived from a wiring material, a halide derived from an etching gas, and the like.

Since the conventional stripping solution is designed for stripping an organic photoresist, such a sidewall cannot be sufficiently stripped and removed. Further, halogen radicals and halogen ions generated during the dry etching with a halogen-based gas are confined in the sidewalls, and the moisture in the air generates an acid to corrode the wiring material (after-corrosion). Therefore, the sidewall must be completely removed. However, it is difficult to remove the sidewall with a commonly used resist stripping solution.

For example, with an alkylbenzenesulfonic acid-based acidic stripper, it is difficult to remove the sidewalls even when heated to a high temperature of 100 ° C. In addition, since these acidic strippers have low solubility in water, they need to be rinsed with a water-soluble organic solvent such as isopropyl alcohol (hereinafter referred to as IPA) before washing, which complicates the process. On the other hand, it is difficult to remove the sidewalls even when the organic amine-based basic stripping solution is heated to a high temperature of 100 ° C. Immediately after washing with water, the organic amine component and water exhibit strong basicity due to the action of water, and cause corrosion of wiring materials. Therefore, it is necessary to perform rinsing with IPA or the like prior to washing with water, which complicates the process.

[0006] JP-A-6-202345 proposes a highly crosslinked or cured photoresist stripping composition comprising a stripping solvent such as 2-pyrrolidinone, an amine, and a weak acid. Japanese Patent Application Laid-Open No. 7-219240 proposes a positive resist stripping solution in which a carboxyl group-containing organic compound is mixed with a resist stripping composition comprising a nitrogen-containing organic hydroxyl compound. It is difficult to remove the sidewall with the liquid.

Further, Japanese Patent Application Laid-Open No. 9-213612 proposes a method in which a photoresist is stripped with a basic stripper containing monoethanolamine or the like, and then washed with water containing a peroxide. If the photoresist is stripped with a basic stripper containing monoethanolamine, etc., and washed with water, the amine will be diluted with water and dissociated, exhibiting a strong basicity. It is considered to be washed with water containing the substance. However, this method has two drawbacks and is disadvantageous in that it is complicated and costly. Further, an acid such as hydrochloric acid or sulfuric acid, or a base such as an aqueous solution of an alkylamine or an alkanolamine can remove the sidewall by dissolving aluminum of the wiring material, but cannot avoid corrosion of the wiring material. .

[0008] At present, release agents (acidic component, basic component, ammonium fluoride, etc.), organic solvents, anticorrosives (catechols, reducing sugars, etc.), additives (surfactants, chelating agents, etc.) and water Although a sidewall removing solution composed of such a component is used, even if the sidewall removing solution comprising such components can remove the sidewall, corrosion of the wiring material cannot be avoided.

[0009]

As described above, sidewalls formed by dry etching after formation of a photoresist, such as sidewalls formed as a result of a chemical reaction between the photoresist, a wiring material, and an etching gas. Development of a removal solution that can easily remove sidewalls, which are compounds having a complex composition consisting of organic substances derived from photoresist, inorganic substances derived from wiring materials, and halides derived from etching gases, without corroding the wiring materials Is required. SUMMARY OF THE INVENTION It is an object of the present invention to provide a sidewall removing solution that can easily remove a sidewall in a single step at a low temperature and at a low cost without corroding a wiring material.

[0010]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, by adding an oxidizing agent to the conventional side wall removing solution, the wiring material can be cooled at a low temperature without corroding. The inventors have found that the sidewall can be easily removed at a low cost in a single step in a short time, and have reached the present invention.

[0011] That is, the invention of claim 1 for solving the above-mentioned problem is a side wall removing solution containing an oxidizing agent.

According to a second aspect of the present invention, in the sidewall removing solution according to the first aspect, the oxidizing agent is ozone, hydrogen peroxide, hypochlorous acid or hypochlorite, chlorite or chlorite. Chlorate, perchloric acid or perchlorate, hypobromite or hypobromite, bromate or perbromite, perbromate or perbromate, hypoiodite or hypoiodite Acid salt, iodic acid or periodate, periodate or periodate, persulfate or persulfate, peracetic acid or peracetate, perpropionic acid or perpropionate, perbenzoic acid or perbenzoate At least one oxidizing agent selected from the group consisting of acid salts, tert-butyl hydroperoxide, ethylbenzene hydroperoxide and cumene hydroperoxide.

According to a third aspect of the present invention, in the sidewall removing solution according to the first or second aspect, the oxidizing agent concentration is 0.1% by weight to 50% by weight. It is.

[0014]

Embodiments of the present invention will be described below in detail. The sidewall removing solution of the present invention generally contains a stripping agent, an organic solvent, an anticorrosive, an additive, water, and the like, and an oxidizing agent. Examples of the release agent used in the present invention include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, formic acid, lactic acid, benzoic acid, methanesulfonic acid, acids such as benzenesulfonic acid, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine. Alkylamines such as diethylamine, triethylamine, n-propylamine, and isopropylamine; alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, and dimethylmonoethanolamine; and organic bases such as tetramethylammonium hydroxide And fluorides such as hydrofluoric acid and ammonium fluoride. These may be used alone or in combination of two or more.

As the organic solvent used in the present invention, any solvent can be used as long as it is uniformly compatible with the other components. Generally, the organic solvent is often water-soluble, but is not particularly limited. Specifically, for example, alcohols such as methanol, ethanol, n-propanol, 2-propanol, n-butanol, sec-butanol, tert-butanol, ethylene glycol, propylene glycol, 1,3-propanediol, 1,2 -Diols such as butanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether , Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, propylene Glycol monomethyl ether, propylene glycol monoethyl ether,
Dipropylene glycol monomethyl ether, ether alcohols such as dipropylene glycol monoethyl ether, formamide, N-methylformamide,
N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide,
Examples include amides such as N, N-dimethylacetamide, N-methylpropionamide, 2-pyrrolidone, N-methylpyrrolidone, dimethylsulfoxide, and sulfolane. These may be used alone, may be used in combination of two or more, or may not be used.

Examples of the anticorrosive used in the present invention include sugars such as glucose, mannose, galactose, sorbitol, mannitol, xylitol and the like.
Sugar alcohols, phenol, cresol, catechol, resorcin, 2,3-pyridinediol, pyrogallol, salicylic acid, aromatic hydroxy compounds such as gallic acid, 3-methyl-1-butyn-3-ol, 3-methyl-1- Pentyn-3-ol, 3,6-dimethyl-4
-Octin-3,6-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,5-dimethyl-1-hexyn-3-ol, 2-butyne-1,
Alkyne alcohols such as 4-diol, triazoles such as benzotriazole, o-tolyltriazole, m-tolyltriazole, p-tolyltriazole, carboxybenzotriazole, 1-hydroxybenzotriazole, nitrobenzotriazole, dihydroxypropylbenzotriazole, etc. Can be given. These may be used alone, may be used in combination of two or more, or may not be used.

The additives used in the present invention include, for example, surfactants and chelating agents. These may be added alone, may be added in combination of two or more, or may not be added.

In the present invention, water is usually used. The present invention is accomplished by further adding an oxidizing agent to a composition comprising these components.

The oxidizing agent used in the present invention includes, for example,
Ozone, hydrogen peroxide, hypochlorous acid or hypochlorite,
Chlorite or chlorite, perchlorate or perchlorate, hypobromite or hypobromite, bromite or perbromite, perbromate or perbromate, hypoiodite Acid or hypoiodite, iodic acid or iodate,
Periodate or periodate, persulfate or persulfate, peracetic acid or peracetate, perpropionic acid or perpropionate, perbenzoic acid or perbenzoate, ter
t-butyl hydroperoxide, ethylbenzene hydroperoxide, cumene hydroperoxide and the like. These may be added alone or 2
You may add in combination of seed | species or more.

The concentration of the oxidizing agent added is preferably in the range of 0.1% by weight to 50% by weight based on the whole composition. 0.
If the amount is less than 1% by weight, the corrosion of the wiring material may not be sufficiently suppressed, and if the amount exceeds 50% by weight, the effect is not improved.

The principle that the side wall removing liquid of the present invention can remove the side wall at a low temperature and in a short time without corroding the wiring material is not clear. Although the present invention is not limited to the following concept, by dissolving a very small amount of the metal component of the wiring material with the sidewall removing solution of the present invention, the sidewall on the outside is peeled off and the oxidizing action of the oxidizing agent is performed. Therefore, it is presumed that the metal surface of the wiring material is oxidized to form a passivation film, so that the sidewall can be easily removed in a short time at a low temperature without corroding the wiring material.

FIGS. 1A to 1E are explanatory views for explaining a step of removing a sidewall using the sidewall removing solution of the present invention. (A) is an insulating layer 2 such as SiO ₂ on a silicon substrate 1 and an Al serving as a wiring material thereon.
A step of forming a metal layer 3 such as, for example, forming a positive photoresist layer 4 thereon, and further superposing a photomask 5 thereon to perform exposure. The resist exposed to light becomes soluble in the alkaline aqueous solution developer. (B) shows a step of forming a resist pattern by performing a developing process. The light-exposed portions of the resist are removed. (C) shows a step of dry-etching the exposed metal layer 3. The side wall 6 is formed at the same time as the portion of the metal layer 3 where the resist is removed is etched. The sidewall 6 also has a role of protecting the remaining metal layer 3 from being excessively etched. (D) shows a step of obtaining the metal wiring pattern 3 by removing the resist pattern 4 by ashing with plasma or the like. (E) shows a step of removing the sidewall 6 using the sidewall removing liquid of the present invention. By using the sidewall removing solution of the present invention, the sidewall 6 can be removed at a low temperature and in a short time without corroding the wiring material.

[0023]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. (Preparation of Substrate) An SiO ₂ film was formed on a silicon wafer substrate, and an Al—Si—Cu layer was formed thereon. A novolak type photoresist was applied thereon, exposed and developed to form a resist pattern. After performing dry etching with a chlorine-based gas, the resist other than the sidewalls was removed by oxygen plasma ashing to obtain a test substrate.

(Examples 1 to 12) The above-mentioned substrate was added to the side wall removing solution of the present invention having the composition shown in Table 1 at 25 ° C. for 1 hour.
After immersion in water, rinsing with water and drying, observation and evaluation were performed by SEM (scanning electron microscope). Table 1 shows the results of evaluating the removability of the sidewall and the corrosiveness of the wiring material. Removability ：: The sidewall is completely removed. ×: The sidewall is not removed. Corrosion ：: No corrosion is observed in the wiring material. ×: Corrosion is observed in the wiring material.

(Comparative Examples 1 to 5) The above substrate was immersed in a liquid having a composition for comparison shown in Table 1 at 25 ° C. for 5 minutes in the same manner as in Examples 1 to 12, after rinsing with water and drying. Observation was evaluated by SEM. Table 1 shows the results of evaluating the removability of the sidewall and the corrosiveness of the wiring material in the same manner as in Examples 1 to 12.

[0026]

[Table 1]

From Table 1, it can be seen that the use of the side wall removing solution (Examples 1 to 12) of the present invention allows the side wall to be removed in a short time at a low temperature without corroding the wiring material. On the other hand, when the removal liquids of Comparative Examples 1 to 5 were used, the sidewalls could be removed, but corrosion was observed in the wiring material.

[0028]

By using the sidewall removing solution of the present invention, the sidewall can be easily removed at a low temperature and in a short time in one process without corroding the wiring material.

[Brief description of the drawings]

FIG. 1A shows an insulating layer 2 such as SiO ₂ on a silicon substrate 1 and a metal layer 3 such as Al serving as a wiring material thereon.
FIG. 4 is an explanatory view showing a step of forming a positive photoresist layer 4 thereon and further exposing and exposing a photomask 5 thereon, and (b) forming a resist pattern by performing a developing process. FIG.
(C) is an explanatory view showing a step of performing a dry etching process on the exposed metal layer 3, and (d) is an explanatory view showing a step of obtaining the metal wiring pattern 3 by removing the resist pattern 4 by ashing. (E) is an explanatory view showing a step of removing the side wall 6 using the side wall removing liquid of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Insulating layer 3 Metal layer 4 Positive photoresist 5 Photomask 6 Sidewall

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kuniaki Miyahara 4980 Kaiseicho, Shinnanyo-shi, Yamaguchi Prefecture Tokuyama Petrochemical Co., Ltd. F-term (reference) 2H096 AA25 LA13 5F043 AA40 BB30 GG02

Claims (3)

[Claims] 1. A side wall removing solution containing an oxidizing agent. 2. The method according to claim 1, wherein the oxidizing agent is ozone, hydrogen peroxide, hypochlorous acid or hypochlorite, chlorite or chlorite, perchloric acid or perchlorate, hypobromous acid or hypochlorous acid. Bromate, bromate or bromate, perbromate or perbromate, hypoiodite or hypoiodite, iodate or iodate, periodate or periodate Salt, persulfate or persulfate, peracetic acid or peracetate,
Being at least one oxidizing agent selected from the group consisting of perpropionic acid or perpropionate, perbenzoic acid or perbenzoate, tert-butyl hydroperoxide, ethylbenzene hydroperoxide, cumene hydroperoxide. The side wall removing liquid according to claim 1, wherein 3. The side wall removing liquid according to claim 1, wherein the concentration of the oxidizing agent is from 0.1% by weight to 50% by weight.