JPH0728254A - Resist release solution - Google Patents

Abstract

PURPOSE:To easily release a side wall protecting deposited film and to enhance noncorrosiveness to a wiring material by forming the resist release soln. with sugar alcohol, etc., alcoholamines, water and further quaternary ammonium hydroxide, if necessary. CONSTITUTION:This soln. is used to remove the deposited film for protecting the side wall of a resist, and consists of at least one kind of material (a) selected from a group consisting of sugar alcohol, isopropyl alcohol, dimethyl sulfoxide and 1,3-dimethyl-2-imidazolidinone, alcoholamine (b), water (c) and further quaternary ammonium hydroxide (d), if necessary. The alcoholamine (b) is selected from a group consisting of monoethanolamine, diethanolamine, etc. Accordingly, the releasability of the side wall protecting deposited film by an org. amine soln. is balanced with the noncorrosiveness of the sugar alcohol or the org. solvent to a wiring material the releasability of the side wall protecting deposited film is improved by the addition of quaternary ammonium hydroxide, and a highly precise circuit wiring is produced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resist stripping solution used in a semiconductor device manufacturing process, and more particularly, to a resist sidewall protection deposition film formed during dry etching of a wiring material by a halogen-based gas, The present invention relates to a resist stripping solution used for stripping a material without corroding it.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, after a required resist mask is formed, a conductive layer in a non-mask region is etched to form a wiring pattern, and then a resist layer on the wiring pattern is unnecessary. A process of removing the resist layer with a stripping solution is required.

In recent years, with the increase in the density of integrated circuits, a resist containing an alkali-soluble resin as a main component, which is advantageous for forming a highly precise fine pattern, has been used. In addition, as the etching technology, the dry etching technology that enables higher density fine etching is used in comparison with the conventional chemical etching technology that uses chemicals, and this is the mainstream. For, the anisotropic dry etching using a halogen-based gas is widely used.

In such dry etching, anisotropic etching is possible by utilizing a sidewall protection deposited film of a resist, but this sidewall protection deposited film has a problem that it is less likely to be peeled off than an ordinary resist. The halogen radicals and halogen ions taken into the side wall protective deposition film, when left in the air after completion of etching, generate acid due to moisture absorption and corrode wiring materials. This is usually called after-corrosion (Semiconductor
r World 1991, 11, p62-66) This after-corrosion is particularly observed in alloys such as Al-Si and Al-Si-Cu which have been frequently used as wiring materials in recent years.

When attempting to remove such a side wall protective deposited film, the following inconvenient problems are found if a commonly used acidic stripping solution or alkaline stripping solution is used. First, speaking of the acidic stripping solution, for example, in the case of a stripping solution in which a phenol compound, a chlorine-based solvent, and an aromatic hydrocarbon are mixed with alkylbenzene sulfonic acid,
Even if heated to 100 ° C. or more, it is quite difficult to remove the side wall protective deposited film, and since these acidic stripping solutions have low solubility in water, an organic solvent having good compatibility with water after stripping. After rinsing with, an operation of further washing with water must be performed, which complicates the process. There is also a problem that the wiring material is corroded by the acidic component generated during washing with water. Also, when a stripping solution consisting of an organic amine, which is a typical alkaline stripping solution, and various organic solvents is used, the sidewall protection deposited film is stripped even when heated to 100 ° C. or higher as in the case of the above acidic stripping solution. However, since these alkaline stripping solutions are water-soluble, there is also a problem that the wiring material is corroded by an alkaline component upon washing with water after stripping. As a result of these, since the sidewall protection deposited film cannot be completely stripped by using either acidic or alkaline stripping solution, the occurrence of after-corrosion is often observed due to residual halogen radicals or halogen ions. It

Further, the resist residue after plasma ashing is treated with tetramethylammonium hydroxide (hereinafter, referred to as T
Although a method of removing it with an aqueous solution of MAH) is known, this method has a problem that a conductive layer made of a substrate containing aluminum is severely corroded. Even if the concentration of TMAH is reduced to suppress the corrosion phenomenon of the conductive layer, since TMAH is a strong alkali, absorption of carbon dioxide gas from the atmosphere causes a large decrease in pH of the aqueous solution and peeling of the sidewall protective deposited film. It will be difficult.

Under these circumstances, the development of a stable resist stripping solution that can easily strip the sidewall protection deposited film and does not corrode the conductive layer made of the aluminum-containing substrate at that time has been developed. Is requested.

[0008]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventors to solve the above-mentioned technical problems in removing the sidewall protective deposition film of a resist in the prior art, (a) sugar alcohol, isopropyl alcohol , Dimethyl sulfoxide and 1,3-dimethyl-2-imidazolidinone, at least one substance selected from the group consisting of: (b) alcohol amine, (c) water, and optionally (d) fourth
It has been found that a solution consisting of a quaternary ammonium hydroxide easily peels off the sidewall protective deposited film and enhances the non-corrosiveness to the wiring material.

That is, the present invention provides a liquid for removing a sidewall protective deposition film of a resist, which comprises (a) sugar alcohol, isopropyl alcohol, dimethyl sulfoxide and 1,
At least one substance selected from the group consisting of 3-dimethyl-2-imidazolidinone, (b) an alcohol amine, (c) water, and optionally (d) a quaternary ammonium hydroxide. A stripper for resist is provided.

The resist stripping solution according to the present invention harmonizes the stripping ability of the side wall protective deposited film of the organic amine aqueous solution and the non-corrosiveness of the sugar alcohol or the organic solvent with respect to the wiring material, and also the quaternary ammonium hydroxide. The addition improves the peelability of the sidewall protection deposited film, and enables the manufacture of highly accurate circuit wiring. The present invention will be described in detail below.

Examples of the sugar alcohol include D-sorbitol, arabitol, mannitol and the like.
The above sugar alcohol, isopropyl alcohol, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidinone may be used alone or in combination of two or more kinds.

Examples of the alcohol amine include monoethanolamine, diethanolamine, triethanolamine and the like. These may be used alone or in combination of two or more kinds. Examples of the above quaternary ammonium hydroxide include ammonium hydroxide, tetramethylammonium hydroxide and trimethyl (2-
Examples thereof include hydroxyethyl) ammonium hydroxide, and these can be used alone or in combination of two or more kinds.

Other components can be appropriately added to the resist stripper according to the present invention. For example, a conventional surfactant can be added to reduce the surface tension or prevent redeposition of the resist on the substrate.

With respect to the preferable blending ratio of each component in the removing liquid according to the present invention, these are determined according to the properties of the side wall protective deposition film and the substrate. Usually, water is blended in an amount of 5% by weight or more and less than 99% by weight, preferably 7 to 95% by weight. In this case, if it is less than 5% by weight, the removal ability of the sidewall protection deposited film is lowered, and if it is 99% by weight or more, the wiring material is easily corroded.

Alcohol amine is 0.1% by weight.
The content is 80% by weight or more and preferably 0.3 to 50% by weight. In this case, if it is less than 0.1% by weight, the removal ability of the sidewall protective deposited film is lowered, and if it is 80% by weight or more, the wiring material is easily corroded.

Further, the compounding ratio of the substance selected from sugar alcohol, isopropyl alcohol, dimethyl sulfoxide and 1,3-dimethyl-2-imidazolidinone is usually 1% by weight or more and less than 90% by weight, preferably 3 to 8%.
It is 0% by weight. In this case, if it is less than 1% by weight, the wiring material is likely to be corroded, and if it is 90% by weight or more, the removal ability of the sidewall protective deposited film is lowered.

In addition, the quaternary ammonium hydroxide compounded for the purpose of enhancing the removal ability of the side wall protective deposited film is 0.1% or less.
01% by weight or more and less than 20% by weight, preferably 0.1 to 2
It is preferable to blend in a weight percentage. 0.0 in this case
If it is less than 1% by weight, the effect of improving the removal ability of the side wall protective deposited film cannot be expected, and if it is 20% by weight or more, the wiring material is rather corroded.

As for the preferred method of using the removing liquid according to the present invention, the substrate having the sidewall protective deposited film remaining thereon is put into this removing liquid, immersed at room temperature or by heating for about 1 to 10 minutes, and then washed with water. Or rinse with an organic solvent such as isopropyl alcohol, wash with water and dry.

The present invention will be described in more detail below with reference to examples of the present invention together with comparative examples. The peeling condition of the side wall protective deposited film, the corrosiveness of the wiring material, and the occurrence condition of after-corrosion were evaluated by a film thickness meter, an optical microscope and a scanning electron microscope (SEM) using the following two types of substrates.

Substrate Preparation Example 1 A CVD oxide film, which is an insulating film, is formed on a Si substrate, and an Al-Si-Cu layer (Si content: 1% by weight, Cu content: 0.5% by weight) is formed thereon. Formed. Next, Al-Si-C
Applying positive photoresist on u layer (coating)
Then, it was exposed and developed to form a resist mask. At this time, the positive photoresist is mainly composed of novolac resin and has a film thickness of 15000Å. And 15
After performing post-baking at 0 ° C. for 30 minutes, the conductive layer (non-mask region) not covered with the resist mask was removed by dry etching using a chlorine-based gas. Subsequently, the resist other than the side wall protective deposition film was removed through an ashing process, and ultrapure water cleaning was performed.

Substrate Preparation Example 2 A CVD oxide film as an insulating film was formed on a Si substrate, and an Al-Si layer (Si content: 1% by weight) was formed on the CVD oxide film.
Next, a positive photoresist was applied (coated) on the Al-Si layer, exposed and developed to form a resist mask. At this time, the positive photoresist is mainly composed of novolac resin and has a film thickness of 15000Å. Then, after post-baking at 150 ° C. for 30 minutes, the conductive layer (non-mask region) not covered with the resist mask was removed by dry etching using a chlorine-based gas. Subsequently, the resist other than the side wall protective deposition film was removed through an ashing process, and ultrapure water cleaning was performed.

[0022]

【Example】

Example 1 A substrate prepared in Example 1 for preparing a substrate was immersed in an aqueous solution of 1.4 wt% of triethanolamine and 5 wt% of D-sorbitol at 23 ° C. for 1 minute and then rinsed with water for 3 minutes to remove the side wall protective deposited film. The corrosiveness of the wiring material was evaluated. As a result, the sidewall protective deposited film was peeled off, and no corrosion of the patterned conductive layer surface was observed.

Example 2 The substrate prepared in Example 1 for preparing a substrate was immersed in an aqueous solution of 0.31 wt% of triethanolamine and 70 wt% of isopropyl alcohol at 23 ° C. for 1 minute and then washed with water for 3 minutes to remove the side wall protective deposited film. The situation and the corrosiveness of the wiring material were evaluated. As a result, the sidewall protective deposited film was peeled off, and no corrosion of the patterned conductive layer surface was observed.

Example 3 63 wt% dimethyl sulfoxide, 1,3-dimethyl-
2-Imidazolidinone 18 wt%, monoethanolamine 9 wt%, tetramethylammonium hydroxide 0.24 wt% Substrates prepared in Example-2 were immersed for 5 minutes at 25 ℃, then rinsed with isopropyl alcohol for 3 minutes in an aqueous solution of 0.24 wt% After that, the substrate was washed with water for 3 minutes, and the peeling state of the sidewall protective deposited film and the corrosiveness of the wiring material were evaluated. As a result, the sidewall protective deposited film was peeled off, and no corrosion of the patterned conductive layer surface was observed.

Example 4 Substrate prepared in Example 2 of substrate preparation was immersed in an aqueous solution of 80% by weight of dimethyl sulfoxide, 10% by weight of monoethanolamine and 0.24% by weight of tetramethylammonium hydroxide at 25 ° C. for 5 minutes and then with isopropyl alcohol. After rinsing for 3 minutes, it was washed with water for 3 minutes and dried, and the peeling state of the sidewall protection deposited film and the corrosiveness of the wiring material were evaluated.
As a result, the sidewall protective deposited film was peeled off, and no corrosion of the patterned conductive layer surface was observed.

Comparative Example 1 The substrate prepared in Example 1 for preparing a substrate in a commercially available stripping solution-1 (acidic stripping solution) was immersed at 110 ° C. for 10 minutes and then washed with water to remove the side wall protective deposited film and corrode the wiring material. The sex was evaluated. As a result, the sidewall protection deposited film was not peeled off.

Comparative Example 2 Example of Substrate Preparation in Commercial Stripper-2 (Alkaline Stripper)
The substrate prepared in 1 was immersed in 100 ° C. for 10 minutes and then washed with water to evaluate the peeling state of the sidewall protection deposited film and the corrosiveness of the wiring material. As a result, the sidewall protection deposited film was not peeled off.

Comparative Example 3 The substrate prepared in Example 1 of substrate preparation was immersed in 200 ml of a 2.4 wt% aqueous solution of tetramethylammonium hydroxide at 23 ° C. for 1 minute and then washed with water to remove the side wall protective deposited film and the wiring material. The corrosiveness was evaluated. As a result, although the sidewall protection deposited film was peeled off, many pit-like corrosions were observed.

Comparative Example 4 The substrate prepared in Example-2 of substrate preparation was immersed in a commercial stripper-1 (acidic stripper) at 110 ° C. for 10 minutes and then washed with water to remove the sidewall protection deposited film and corrode the wiring material. The sex was evaluated. As a result, the sidewall protection deposited film was not peeled off.

Comparative Example 5 Example of Preparation of Substrate in Commercial Stripper-2 (Alkaline Stripper)
The substrate prepared in 2 was immersed in 100 ° C. for 10 minutes and then washed with water to evaluate the peeling state of the sidewall protection deposited film and the corrosiveness of the wiring material. As a result, the sidewall protection deposited film was not peeled off.

COMPARATIVE EXAMPLE 6 The substrate prepared in Example-2 was prepared in a 2.4 wt% tetramethylammonium hydroxide aqueous solution.
After dipping at 1 ° C. for 1 minute and then rinsing with water, the state of peeling of the sidewall protective deposited film and the corrosiveness of the wiring material were evaluated. As a result, although the sidewall protection deposited film was peeled off, many pit-like corrosions were observed.

The resist stripper according to the present invention is capable of enhancing the strippability of the resist formed during the dry etching with a halogen-based gas from the sidewall protection deposited film and the noncorrosiveness of the wiring material. In addition, it has extremely excellent properties including after-corrosion prevention properties, stability in the air, and ease of work. This stripper does not have a harmful effect on the human body or the environment.

Claims (4)

[Claims] 1. A liquid for removing a sidewall protective deposition film of a resist, which comprises (a) sugar alcohol, isopropyl alcohol, dimethyl sulfoxide and 1,3-dimethyl-2.
A resist stripping solution comprising at least one substance selected from the group consisting of imidazolidinone, (b) alcohol amine, (c) water and optionally (d) quaternary ammonium hydroxide. 2. The resist stripper according to claim 1, wherein the alcohol amine is selected from the group consisting of monoethanolamine, diethanolamine and triethanolamine. 3. The resist stripper according to claim 1, wherein the sugar alcohol is D-sorbitol. 4. The resist stripper according to claim 1, wherein the quaternary ammonium hydroxide is selected from the group consisting of ammonium hydroxide, tetramethylammonium hydroxide and trimethyl (2-hydroxyethyl) ammonium hydroxide. .