JPH0934129A - Removing solution for photoresist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a removing soln. not requiring rinsing with a special rinsing soln. and having superior removing performance and dissolving abililty even to a photoresist film post-baked at a high temp. or a photoresist film exposed to plasma or ions. SOLUTION: This removing soln. for removing a photoresist film formed on a substrate by coating consists of amino-alcohol (A), N,N-dimethylformamide (B) and glycol monoalkyl ether (C). The amt. of the component A is 5-38wt.%, the total amt. of the components B, C is 95-62wt.% and the weight ratio of the component C to the component B is 0.05-0.8.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a stripping solution for photoresist. More specifically, the present invention relates to a substrate used in a lithographic process, particularly when manufacturing an LCD (liquid crystal display) on a glass substrate or when manufacturing an LSI (large scale integrated circuit) on a semiconductor substrate. A stripping solution for removing the applied photoresist film, which does not require a rinse treatment with a special rinse solution,
Further, the present invention relates to a photoresist stripping solution that can exhibit excellent stripping performance and dissolution performance even for a photoresist film post-baked at high temperature or a photoresist film exposed to plasma or ions.

[0002]

2. Description of the Related Art In the LSI manufacturing process, a positive photoresist capable of forming a fine pattern is used because of the recent demand for higher integration. Further, even in the LCD manufacturing process, a positive photoresist is used because of the application of the LSI manufacturing process, although there is no demand for a fine pattern like that of the LSI. When forming an acid-insoluble pattern on a Si (silicon) substrate or silicon oxide, a method of using a mixed solution of sulfuric acid-hydrogen peroxide as a resist stripping solution is generally used, but Al (aluminum) wiring and ITO (indium tin composite) are used. When a pattern such as (oxide) wiring is formed, the mixed solution is inconvenient because it dissolves Al, ITO, etc. which should be left on the substrate.

Conventionally, as a general stripping method for a positive resist pattern, (a) a method using a phenol stripping solution (Japanese Patent Publication No. 5-67030, etc.), and (b) ashing removal using oxygen plasma Method (JP-A-6
No. 3-260032).

However, in the method (a), the stripping solution to be used contains harmful phenol as a main component, and harmful chlorine-based solvents such as dichlorobenzene and tetrachloroethylene are added, which is a safety and health concern. There is a problem from a perspective. Further, it requires rinsing with an organic solvent such as trichlene that dissolves these solvents, and since this stripping solution becomes acidic due to moisture absorption, it has a disadvantage that it easily corrodes Al and the like used for wiring.

The method (b) is superior to the method using a stripping solution in that waste liquid treatment is not required, but it requires a vacuum device, which increases the cost of the apparatus and the stripping rate in the plane of the substrate. Is less likely to be uniform, resist residues tend to occur, and it takes longer than the method using a stripping solution, resulting in a decrease in throughput.

In addition, a method using an amine-based water-soluble stripping solution is also known (Japanese Patent Publication No. 64-5695, etc.), but this method eliminates the drawbacks of the methods (a) and (b) to some extent. However, as a stripper, a stripper having sufficiently satisfactory performance has not been obtained.

By the way, in recent years, in order to improve the processing accuracy of the substrate, there is a tendency that the post-baking temperature after development is increased to harden the photoresist more strongly and to improve its heat resistance. Also, when dry etching or ion implantation is performed during microfabrication, the photoresist is exposed to plasma or ions or exposed to high heat at that time, which causes alteration or hardening, and more firmly adheres to the substrate to prevent peeling. At the same time, the resist residue that has been stripped is less likely to dissolve in the stripping solution. When the resist residue remains in the stripping solution, the residue re-adheres on the substrate, which is extremely inconvenient. That is, it is necessary that the stripping liquid has both excellent stripping performance and dissolution performance. Then, the appearance of a stripping solution that is more excellent in stripping performance and dissolution performance than conventional stripping solutions is strongly desired.

[0008]

In such a situation,
The problem to be solved by the present invention is a stripping solution for removing a photoresist film coated on a substrate, which does not require a rinse treatment with a special rinse solution, and which is post-baked at a high temperature. An object of the present invention is to provide a stripping solution for photoresist that can exhibit excellent stripping performance and dissolution performance even for a resist film or a photoresist film exposed to plasma or ions.

[0009]

That is, the present invention is a stripping solution for removing a photoresist film coated on a substrate, which comprises the following components (A), (B) and (C):
The content of the component (A) is 5 to 38% by weight, and the total content of the component (B) and the component (C) is 95 to
It relates to a stripping solution for photoresist having a weight ratio of component (C) / component (B) of 0.05 to 0.8, which is 62% by weight. (A): Amino alcohol (B): N, N-dimethylformamide (C): Glycol monoalkyl ether

The details will be described below.

In the present invention, the substrate means a semiconductor substrate such as a Si wafer for producing LSI, a Ga (gallium) -As (arsenic) wafer or the like, or a glass substrate for producing LCD, and further, on those substrates, a dioxide is formed. Silicon, silicon nitride, polysilicon, amorphous silicon, Ga-A
s, Ga-Al-As, aluminum, aluminum oxide, copper, ITO, chromium, chromium oxide, molybdenum, molybdenum oxide, tantalum, tantalum oxide, titanium, titanium oxide, titanium nitride, etc. are also included. .

The component (A) of the present invention is amino alcohol. Specific examples thereof include 2-aminoethanol,
1-amino-2-propanol, 2-amino-1-propanol, 3-amino-1-propanol, 2-amino-1-butanol, 4-amino-1-butanol, etc. can be mentioned. Among them, 2-aminoethanol is preferable from the industrial viewpoint in consideration of peeling performance and price. The amino alcohol which is the component (A) may be a general industrial grade one, but the intended use is L
Since it is an SI or LCD manufacturing process, one having a low content of metals is preferable.

(A) in a stripping solution for photoresist
The content of the components is 5 to 38% by weight, preferably 15 to 3
8% by weight. If the content of the component (A) is too small, the stripping performance is deteriorated, while if the content is too large, the dissolution performance of the stripped photoresist is deteriorated.

The component (B) of the present invention is N, N-dimethylformamide, which may be a general industrial grade, but since it is used in the LSI or LCD manufacturing process, it has a low content of metals. Those are preferable.

The component (C) of the present invention is a glycol monoalkyl ether. Specific examples of glycol monoalkyl ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether,
Examples thereof include diethylene glycol monobutyl ether. Of these, diethylene glycol monobutyl ether is preferable. The glycol monoalkyl ether may be a general industrial grade one, but since it is used in the LSI or LCD manufacturing process, one having a low metal content is preferable.

The total content of the components (B) and (C) in the photoresist stripping solution of the present invention is 95-62.
%, Preferably 85 to 62% by weight. If the total content is too small, the dissolution performance of the stripped photoresist is deteriorated, while if the total content is too large, the separation performance is deteriorated.

The weight ratio of component (C) / component (B) in the photoresist stripping solution of the present invention is 0.05 to 0.
8, preferably 0.05 to 0.25. If the ratio is too small, the dissolution performance of the peeled photoresist decreases,
On the other hand, if the ratio is too large, the peeling performance will be deteriorated.

In order to obtain the photoresist stripping solution of the present invention, the components (A), (B) and (C) may be mixed in predetermined amounts. For example, a known method such as preparing a mixer having a simple stirrer, introducing the three components, and stirring at room temperature can be used. The liquid after mixing is
By filtering with a filter of 0.2 μm or less, it is possible to remove fine particles that are disliked in the LCD or LSI manufacturing process.

The method of stripping the photoresist film on the substrate using the stripping solution according to the present invention includes a method of simply dipping the substrate in the stripping solution, a method of dipping the substrate in the stripping solution, ultrasonic vibration and Examples thereof include a method of stirring the stripping solution with a stirring blade, a method of spraying the stripping solution on the substrate, and the like. The temperature of the stripping solution during the stripping operation is preferably 20 to 90 ° C.

By using the stripping solution of the present invention, 11
Not only the photoresist that has been normally post-baked at 0 ° C., but also a positive photoresist film that has been post-baked at a temperature of 150 ° C. or higher, a photoresist film that has been exposed to plasma, or a photoresist film that has been exposed to ions Such a highly hardened or altered photoresist film can be easily peeled off.

Further, the stripping solution according to the present invention is characterized in that it does not require a rinsing treatment with a special rinsing solution such as trichlene because the constituents are all water-soluble, and the process can be simplified. .

[0022]

The present invention will be described in more detail with reference to the following examples.

Examples 1 to 3 and Comparative Examples 1 to 3 A positive photoresist is applied on a silicon wafer to a thickness of 1.2 μm, a pre-baking process is performed, and then exposure and development are performed as a photolithography process. Thus, a resist pattern was formed and post baking was performed at 200 ° C. for 30 minutes. The wafer with the resist pattern was used, immersed in a stripping solution, and washed with water. The wafer after washing with water was observed with an optical microscope, the time required for peeling was determined from the residual state of the photoresist, and the peeling performance was evaluated.
The results are shown in Table 1.

Examples 4 to 15 and Comparative Examples 4 to 14 Here, an experiment was conducted without forming a pattern so that the dissolution performance of the peeled photoresist film can be observed and the dissolution performance can be measured. That is, a positive photoresist was applied to a thickness of 1.2 microns on a silicon wafer having a thermal oxide film of about 1 micron, prebaked, and then baked again at 180 ° C or 200 ° C. The substrate with the photoresist was immersed in a stripping solution having various compositions, and the stripping state and the dissolving state were observed. In addition,
The 180 ° C-baked one was used for the dissolution time measurement, and the 200 ° C-baked one was used for the peeling time measurement. The liquid temperature in the peeling experiment was 50 ° C and the liquid temperature in the melting experiment was 80 ° C. The results are shown in Tables 2 to 5. The peeling performance was evaluated using an optical microscope as in Example 1. In addition, the determination of dissolution performance is
The disappearance of the resist pieces in the stripper due to dissolution was visually observed.

Example 16 and Comparative Example 15 A positive type photoresist was applied to a thickness of 1.2 μm on a silicon wafer having a thermal oxide film of about 1 μm, prebaked and then subjected to photolithography. A resist pattern was formed by performing exposure and development, and post baking was performed at 120 ° C. for 30 minutes. The wafer with the resist pattern was placed in a dry etching apparatus, and etching was performed with CHF ₃ gas plasma containing 2% by volume of oxygen to form a pattern of an oxide film. Table 4
After the stripping treatment was performed at 80 ° C. for 5 minutes using the two types of stripping solutions shown in 1), the stripping state of the photoresist was observed with an electron microscope. The results are shown in Table 6.

[0026]

[Table 1] ------------------------------------- Examples Comparative Examples Comparative Examples 1 2 1 2 3 3 Stripper composition * 1 (A) wt% 30 30 30 0 30 30 (B) wt% 60 40 0 70 60 0 (C) wt% 10 30 70 30 10 70 (C) / (B) wt ratio 0.17 0.75 -0.43 0.17-Stripper temperature ℃ 50 ← ← ← 80 ← Minute of stripping time 1 2> 30> 30 <1> 30 −−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−

[0027]

[Table 2] -------------------------------------------- Example 4 5 6 7 8 9 Stripping solution composition * 1 ( A) wt% 35 35 35 30 30 30 (B) wt% 60 50 40 65 60 40 (C) wt% 5 15 25 5 10 30 (C) / (B) wt ratio 0.08 0.30 0.63 0.08 0.17 0.75 1 1 2 1 1 2 Dissolution time Minutes 17 18 17 17 17 16 16 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0028]

[Table 3] ------------------------------------------- Actual Example 10 11 12 13 14 15 Stripping solution composition * 1 ( A) wt% 20 20 20 10 10 10 (B) wt% 70 60 50 80 70 60 (C) wt% 10 20 30 10 20 30 (C) / (B) wt ratio 0.14 0.33 0.60 0.13 0.29 0.50 1 2 2 1 1 2 Dissolution time Minutes 16 16 17 16 18 16 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0029]

[Table 4] ------------------------------------------------ Comparative Example 4 5 6 7 8 9 Stripping solution composition * 1 ( A) wt% 100 70 50 50 50 40 (B) wt% 0 30 50 40 0 30 (C) wt% 0 0 0 10 50 30 (C) / (B) wt ratio-0 0 0.25-1 Peeling time 2 2 2 2 4 3 Dissolution time Minutes> 30> 30 28 23 25 22 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0030]

[Table 5] ------------------ Comparative example 10 11 12 13 14 Stripper composition * 1 (A) wt% 30 30 30 20 0 (B) wt% 70 20 0 40 70 (C) wt% 0 50 70 40 30 (C) / (B) wt ratio 0 2.5-1 0.43 Peeling time min 1 4 8 3> 30 Melting time min 20 18 21 20> 30 −−−−−−−−−−−−−−−−−−−−−−−−−−

[0031]

[Table 6]

* 1 Stripping solution composition (A): 2-aminoethanol (B): N, N-dimethylformamide (C): Diethylene glycol monobutyl ether * 2 Stripping situation (presence or absence of photoresist residue on oxide film pattern) : No residue was found. X: Significant residue was found.

[0033]

As described above, according to the present invention, a stripping solution for removing a photoresist film coated on a substrate, which does not require a rinsing treatment with a special rinsing solution, and can be post-processed at a high temperature. It has been possible to provide a photoresist stripping solution capable of exhibiting excellent stripping performance and dissolution performance even for a baked photoresist film or a photoresist film exposed to plasma or ions.

Claims (3)

[Claims] 1. A stripping solution for removing a photoresist film coated on a substrate, which comprises the following component (A):
Consisting of the component (B) and the component (C), the content of the component (A) is 5 to 38% by weight, the total content of the component (B) and the component (C) is 95 to 62% by weight, A photoresist stripping solution having a weight ratio of component (C) / component (B) of 0.05 to 0.8. (A): Amino alcohol (B): N, N-dimethylformamide (C): Glycol monoalkyl ether 2. The stripping solution for photoresist according to claim 1, wherein the component (A) is 2-aminoethanol and the component (C) is diethylene glycol monobutyl ether. 3. A positive photoresist film post-baked at a temperature of 150 ° C. or higher, a positive photoresist film exposed to plasma, or at least one photoresist film exposed to ions. The stripping solution for photoresist according to claim 1, which is for removing.