JP3373105B2 - Photoresist stripper - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel resist stripping liquid used for removing a photoresist and a residue formed on a substrate from a substrate in manufacturing a semiconductor circuit or the like. More specifically, the present invention relates to a resist stripper that is excellent in resist removability and removability of etching polymers, has less corrosion of a base material, and has excellent storage stability.

[0002]

2. Description of the Related Art When manufacturing a semiconductor microcircuit, processing using a photoresist is usually performed. That is, first, a layer of silicon dioxide, aluminum, or the like, which is a material of an insulating layer or a wiring layer, is formed as a base on a substrate, a photoresist layer is applied thereon, and a resist pattern is formed by exposure and development. Is used as a mask to perform an etching operation of the base to transfer a predetermined circuit pattern to the base layer. After this, it is necessary to remove the photoresist pattern that is no longer needed. This can be done by using a photoresist stripper or by exposing the substrate surface to oxygen-containing plasma to ash and remove the resist. .

Many compositions have been proposed as resist stripping solutions for such purposes. Typical examples thereof include a mixture of a polar organic solvent and an alkanolamine as described in US Pat. No. 4,617,251. However, such a conventional stripping solution has a problem that the etching polymer generated on the side wall of the pattern or the like cannot be completely removed when the underlayer is dry-etched. Further, even if the conditions for removing the etching polymer are found by increasing the liquid temperature of the peeling treatment, there is a problem that the corrosion of the base material cannot be avoided. Further, it is known that when an ashing process is performed to remove the resist, the etching polymer becomes a substance such as a metal oxide and remains on the substrate and becomes more difficult to remove with the above-mentioned stripping solution. For the formation mechanism of such etching polymer and the necessity of its removal, see 1991 SP.
John at IE Microlithography Symposium
Published by W Cobum under the heading "Plasma Etching and Reactive Etching".

In order to eliminate these problems, a photoresist stripping composition having etching polymer removing ability has been newly proposed. JP-A-5-45894 discloses a composition obtained by adding a specific corrosion inhibitor to an organic polar solvent and amine, and JP-A-6-266119 discloses a nucleophilic amine compound having an oxidation and reduction potential, an organic solvent and water, Further, a composition in which a chelating agent is used in combination is disclosed in JP-A-7-219241, in which a specific reducing compound is added to an organic solvent and a nucleophilic amine as a corrosion inhibitor.
No. 7 is a composition in which a nitrogen-containing organic hydroxy compound, a phenol derivative, triazole and an organic solvent are used in combination,
Further, JP-A-7-271057 discloses a composition in which diethylhydroxylamine and an aminoalcohol compound and water and an organic solvent are used in combination, which can be suitably used for such purposes. However, even for these compositions, the removability of the etching polymer and the ability to prevent corrosion of the base are not compatible at a high level, the storage stability of the composition is poor, and for complete removal of the etching polymer, Since it is necessary to raise the liquid temperature,
The components of the stripping solution were volatilized during the treatment, the performance was changed during use, and there were problems such as being unfavorable in terms of environmental protection.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a more excellent resist stripping solution in view of the above problems. In particular, it is to provide a stable stripping solution that has both removability of an etching polymer and corrosion resistance of a substrate in addition to resist removability and has little performance change during storage and use.

[0006]

The above object has been achieved by the following constitution. (1) (a) Organic amine, (b) water, and (c) 2,3-dihydroxynaphthalene represented by the following general formula (I)
The photoresist stripping solution comprising a down compound.

[0007]

[Chemical 5]

In the formula (I), R is a hydrogen atom and has 1 to 3 carbon atoms.
Alkyl group, cycloalkyl group, aryl group, aralkyl group, alkoxy group, carboxyl group, alkyl group ester having 1 to 3 carbon atoms of carboxyl group, halogen atom, sulfonic acid group, amino group, substituted amino group, amide Represents a group or an acyl group.

(2) Further (d) is represented by the following general formula (II).
The photoresist stripping solution according to (1) above , which comprises an α-hydroxyketone compound as described above .

[0010]

[Chemical 6]

In the formula (II), R ₁ is a hydrogen atom and has 1 to 1 carbon atoms.
3 alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, carboxyl groups, alkyl group esters having 1 to 3 carbon atoms of a carboxyl group, halogen atoms, sulfonic acid groups, amino groups, substituted amino groups, amide groups or Represents an acyl group. R ₂ is a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, a cycloalkyl group, an aryl group, an aralkyl group, a carboxyl group, an alkyl group ester having 1 to 3 carbon atoms of a carboxyl group, a halogen atom, a sulfonic acid Represents a group, an amino group, a substituted amino group, an amide group or an acyl group.

[0012]

( 3 ) The photoresist stripping solution as described in (1) or (2) above, which contains a water-containing organic solvent.

[0014]

[Components (c), (d)]

Examples of the alkyl group having 1 to 3 carbon atoms in R, R ₁ and R ₂ of the general formulas (I) and (II) include a methyl group, an ethyl group, a propyl group and an isopropyl group. Examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group. Examples of the aryl group include a phenyl group, a toluyl group, a xylyl group, a cumenyl group, a mesityl group and a naphthyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group and a propoxy group. Examples of the aralkyl group include a benzyl group and a phenethyl group. As the alkyl group having 1 to 3 carbon atoms of the carboxyl group, a methoxycarbonyl group,
Examples thereof include an ethoxycarbonyl group and a propoxycarbonyl group. Examples of the halogen atom include chlorine atom, bromine atom, iodine atom and the like. As the substituted amino group,
Examples thereof include an alkylamino group such as a methylamino group and an arylamino group such as a phenylamino group. Examples of the acyl group include formyl group, acetyl group, propionyl group, benzoyl group and the like. As an amide group,
An acetamide group, a sulfonamide group, etc. are mentioned.

In the substituent of the general formula (I), R is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0016]

[0017]

Further, in the general formula (II), R ₁ is preferably a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms or an aryl group, and particularly preferably a hydrogen atom, a hydroxyl group, a methyl group or a phenyl group. R ₂ is preferably a hydroxyl group, an alkyl group having 1 to 3 carbon atoms or an aryl group, and particularly preferably a hydroxyl group, a methyl group or a phenyl group. General formula (I
Preferred specific examples of the compound represented by I) include hydroxyacetone, benzoin and 2-hydroxypropionic acid. In the present invention, it is preferable to use the compound of general formula (I) and the compound of general formula (II) in combination. Thereby, the removability of the etching polymer and the storage stability become better.

As the [component (a)] organic amine, any of those conventionally used in resist stripping solutions can be used. As an organic amine,
Preferred are compounds represented by the following general formula (III).

[0020]

[Chemical 8]

In the formula (III), R ₃ is an ethyl group, --C ₂ H ₄
OH, a phenyl group or —CH ₂ CH (OH) CH ₃ , R ₄ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkanol or phenyl, and R ₅ is a hydrogen atom, having 1 to 3 carbon atoms. an alkyl group or -C ₂ H ₄ OH. R ₃
And R ₄ may form a 5- or 6-membered ring with the nitrogen atom. Here, the alkyl group having 1 to 3 carbon atoms has the same meaning as described above. Examples of the alkanol include an ethanol group and a propanol group. The 5- to 6-membered ring formed by R ₃ and R ₄ together with the nitrogen atom includes a 2-pyrrolidone ring, a pyrrolidine ring, a pyrrole ring and the like.

Preferred organic amines include monoethanolamine, N-methyl-2-pyrrolidone, methylethylamine, morpholine, 1-amino-2-propanol, 2- (2-aminoethoxy) ethanol, 3-methoxypropylamine, 2-amino-picoline is mentioned.

As the water-containing organic solvent that can be used in the present invention, any one can be used as long as it is usually used in a resist stripping solution. By using the water-containing organic solvent, the resist peeling performance becomes good. Preferable specific examples of such an organic solvent include N-methyl-2-pyrrolidone, 2-pyrrolidone and 1
-Ethyl-2-pyrrolidone, 1-propyl-2-pyrrolidone, 1-hydroxyethyl-2-pyrrolidone, 1-hydroxypropyl-2-pyrrolidone, dimethylsulfoxide and dimethylformamide.

Regarding the compounding ratio of each component used in the stripping solution of the present invention, when the components (a), (b) and (c) are used,
Component (a) 30-9 based on the total weight of the resist stripper
5% by weight, preferably 50 to 90% by weight, component (b) 1
-30 wt%, preferably 5-20 wt%, component (c) 0.1-30 wt%, preferably 1-20 wt%.

[0025]

In the case of comprising the components (a), (b), (c) and (d), the component (a) is 30 to 95% by weight, preferably 50 to 90% by weight based on the total weight of the resist stripping solution. ,
Component (b) 1 to 30% by weight, preferably 5 to 20% by weight, Component (c) 0.1 to 30% by weight, preferably 1 to 2
0% by weight, component (d) 0.1 to 30% by weight, preferably 1 to 20% by weight. Further, in each of the above compositions, the addition amount of an organic solvent capable of containing water is 10 to 70% by weight, preferably 30 to 70% by weight based on the stripping solution.
It is 65% by weight.

The composition of the present invention may be used in combination with various compounds which have been effective in the removal of etching polymers and prevention of corrosion in the prior art. In particular, JP-A-6-2661
Nucleophilic amino compounds such as hydroxylamine described in JP-A-19, chelating agents such as catechol, and the like.
The corrosion inhibitors such as hydroxylquinoline described in JP-A-5894, and the corrosion inhibitors such as hydrazine derivatives, oximes and aromatic hydroxyl compounds described in JP-A-7-219241 are used in combination with the composition of the present invention. can do. Further, by arbitrarily selecting the combination of the composition of the present invention and these compounds, it is possible to design the composition so that the amount of the expensive raw material used is suppressed to the minimum and the required performance is exhibited.

In the present invention, as long as it does not adversely affect the effect of the present invention, any nonionic surfactant which can be mixed with water can be contained, and the content thereof is generally 0. It is in the range of 1 to 2% by weight.

By using the stripping solution of the present invention, the resist pattern used for etching the underlayer of silicon dioxide, aluminum, titanium, tungsten, copper, or an alloy thereof formed on the substrate can be easily stripped. can do. In particular, it is possible to completely remove the etching polymer even at a relatively low temperature without causing corrosion of the base. Further, it is possible to obtain a resist stripper having excellent storage stability.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples, but the contents of the present invention are not limited thereto. [Example-1] A film of Al-Si-Cu alloy was formed on a silicon wafer by using a sputtering apparatus. A positive photoresist, FH-6400, manufactured by Fuji Hunt Electronics Technology Co., Ltd. was applied on this in a thickness of 1 .mu.m, and a line-and-space pattern resist image was formed using a reduction projection exposure apparatus according to a conventional method. Next, using this resist image as a mask, the Al-Si-Cu film on the substrate was etched by a reactive ion etching apparatus. Then, the unnecessary resist film was ashed and removed by a resist ashing apparatus using oxygen plasma.

Observation of the surface of this wafer with a scanning electron microscope revealed that Al--S formed by etching.
It was confirmed that the ashing residue derived from the etching polymer remained on the surface and the side wall of the i-Cu pattern.
Therefore, each stripping solution according to the present invention (Sample 1 described in Table 1
8 ) was heated to 40 ° C. to 80 ° C. to immerse the wafer, and then the wafer was washed with flowing pure water for 20 minutes. Observe the wafer again with a scanning electron microscope and
-Removal of residue remaining on the surface and sidewalls of the -Si-Cu pattern (residual removability at 80 ° C), lower limit temperature at which removal is possible, and the extent to which the Al-Si-Cu pattern is corroded and thinned ( The degree of corrosion of the substrate) was recorded. The evaluation criteria are shown below.

The residue removability was evaluated as ⊚ when there was no residue, ◯ when there was a slight residue, Δ when there was a residue and there was a problem in practical use, and × when there was no residue at all. Regarding the degree of corrosion of the base, ⊚ indicates no corrosion, ∘ indicates slight corrosion, ∆ indicates corrosion and practical problems, and × indicates severe corrosion. Further, in order to test the storage stability of the solution, 1 liter of each stripping solution sample was placed in a 1 liter beaker, kept open at 70 ° C. in the air and allowed to stand overnight. Then, it was examined in the same manner as above whether there was a change in the residue removal performance and the degree of corrosion. When no change was observed in the performance, ◎, when the removability or corrosion slightly deteriorated, ○, when it deteriorated to the extent that it could not be used under the same conditions, △, it deteriorated to the point where it could not be used under any conditions. The case was marked as x. The results are shown in Table-1.

[0033]

[Table 1]

From the results shown in Table 1, the resist stripper of the present invention is excellent in residue removability and has a low removable temperature (70 ° C.).
Below), the substrate was hardly corroded, and the storage stability was excellent. Further, Samples 1 to 4 in which the compound of the general formula (I) and the compound of the general formula (II) of the present invention were used together showed particularly excellent performance.

[Comparative Example-1] For comparison, the performance of the resist stripper having each composition shown in Table-2 was tested and evaluated in the same manner as in Example-1. The results are shown in Table-2.

[0036]

[Table 2]

From the results shown in Table 2, the resist stripping solution for comparison had excellent residue removability, but had a high removable temperature, corroded the substrate, and poor storage stability. .

Example-2 A resist image was formed on the same film as in Example-1 in the same manner. Next, using this resist image as a mask, Al on the substrate
The -Si-Cu coating was etched with a reactive ion etching device. Then, the unnecessary resist film was ashed and removed by a resist ashing apparatus using oxygen plasma until about 80% of its thickness was removed. Next, each stripping solution according to the present invention (Samples 1 to 8 shown in Table 3) was applied at 40 ° C to 80
The wafer was heated to ℃, the wafer was immersed in it to remove the remaining resist film. Further, the wafer was washed for 20 minutes with flowing pure water. Observing this wafer surface with a scanning electron microscope, the presence or absence of resist residue (resist removability), the extent of ashing removal of residue on the surface of the Al-Si-Cu pattern (residue removability), and the lower limit temperature at which removal is possible , Further A
The degree to which the 1-Si-Cu pattern was corroded and thinned (corrosion degree of the base) was recorded. Further, the storage stability of the liquid was tested in the same manner as in Example-1. The results are shown in Table-3.
The resist removability is ◎ when the resist is completely peeled off, ○ when there is slight resist peeling residue, Δ when there is peeling residue and there is a practical problem, and × when the resist is not removed at all. did. Other evaluations are the same as in Example 1.

[0039]

[Table 3]

From the results shown in Table 3, the resist stripper according to the present invention has excellent residue removability and low removable temperature (70 ° C.).
Below), hardly corrodes the substrate and has excellent storage stability,
Moreover, the resist removability was also excellent. Further, Samples 1 to 4 in which the compound of the general formula (I) and the compound of the general formula (II) of the present invention were used together showed particularly excellent performance.

[Comparative Example-2] For comparison, the performance of the resist stripper having each composition shown in Table-4 was tested and evaluated in the same manner as in Example-2. The results are shown in Table-4.

[0042]

[Table 4]

From the results shown in Table 4, the resist stripping solution for comparison was insufficient in any of residue removability, removable temperature, substrate corrosiveness and storage stability.

[0044]

The resist stripping solution of the present invention enables the formation of silicon dioxide, aluminum, titanium, etc. formed on a substrate.
The resist pattern used for etching the underlayer of tungsten, copper, or an alloy thereof can be easily peeled off. In particular, it is possible to completely remove the etching polymer even at a relatively low temperature without causing corrosion of the base. Further, it is possible to obtain a resist stripper having excellent storage stability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/308 H01L 21/306 S (72) Inventor Yoshimi Akutagawa Yoshiji-cho, Shizuoka Prefecture, Kawadajiri 4000 Address Fuji Hunt Electronics Technology Co., Ltd. In-company (72) Inventor Tadaka Kokubo 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Hunt Electronics Technology Co., Ltd. In-company (56) Reference JP-A-5-45894 (JP, A) JP-A-7-219240 ( JP, A) JP 7-271057 (JP, A) JP 7-160009 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (3)

(57) [Claims] 1. An organic amine (a), (b) water, and (c) 2,3-dihydroxy represented by the following general formula (I):
A photoresist stripping solution comprising a synaphthalene compound. [Chemical 1] In formula (I), R is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, a carboxyl group, an alkyl group ester having 1 to 3 carbon atoms. Represents a halogen atom, a sulfonic acid group, an amino group, a substituted amino group, an amide group or an acyl group. 2. The invention further comprises (d) an α-hydroxyketone compound represented by the following general formula (II).
The photoresist stripping solution according to claim 1 . [Chemical 2] In formula (II), R ₁ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a cycloalkyl group, an aryl group, an aralkyl group,
It represents a carboxyl group, an alkyl group ester of a carboxyl group having 1 to 3 carbon atoms, a halogen atom, a sulfonic acid group, an amino group, a substituted amino group, an amide group or an acyl group.
R ₂ is a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, a cycloalkyl group, an aryl group, an aralkyl group,
It represents a carboxyl group, an alkyl group ester of a carboxyl group having 1 to 3 carbon atoms, a halogen atom, a sulfonic acid group, an amino group, a substituted amino group, an amide group or an acyl group. 3. The photoresist stripping solution according to claim 1, which contains a water-containing organic solvent.