JPH09311465A - Adhesive sheet for removing resist and method for removing resist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely remove an unnecessary resist film image on an article with an adhesive sheet independently of the kind and properties of the resist and to prevent the leaving of particles on the article after the removal. SOLUTION: A photosetting adhesive layer ccntg. an org. resin having the same molecular skeleton structure as a resist material is formed on a film substrate to obtain the objective adhesive sheet for removing a resist. This adhesive sheet is stuck on an article on which a resist film image exists, the sheet is photoset and the photoset sheet, together with the resist material, is peeled to remove the resist material on the article.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention eliminates unnecessary resist film images (resist patterns) in the production of microfabricated parts such as semiconductors, circuits, various printed boards, various masks and lead frames. It is related to the technology.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a resist material is applied onto a silicon wafer and a predetermined resist film image is formed by a normal photo process. Using this as a mask, the unnecessary resist material is removed after etching to form a predetermined circuit. Then, in order to form the next circuit, the cycle of applying the resist material again is repeated. Also, when forming a circuit on various substrates, unnecessary resist material is removed after the resist film image is formed.

At this time, the unnecessary resist material is generally removed by an asher (ashing means), a solvent, a chemical, or the like. However, if the asher is used to remove the resist material, it may take a long time for the work, the impurities in the resist material may be injected into the wafer, and the semiconductor substrate may be damaged. In addition, there is a problem that the working environment is harmed when a solvent or a chemical is used.

Therefore, when removing the resist film image,
A method in which a solution of a high molecular polymer is applied onto a semiconductor substrate having the above image and subjected to a specific treatment such as heating and drying, and then the high molecular polymer and the resist material are integrally peeled from the high molecular polymer. A method has been proposed in which the following adhesive sheets are attached to the upper surface of the resist film image, subjected to a specific treatment such as heat treatment, and then the adhesive sheets and the resist material are integrally peeled off. In particular, the latter method is drawing attention as a simple removal method.

[0005]

However, in the method using the adhesive sheet, a part or minute part of the resist material may remain on the article without being peeled off depending on the type and properties of the resist film image. When the resist material is removed after implanting ions into the semiconductor substrate or after dry etching the semiconductor substrate, it may not be removed at all.
It was necessary to repeat the removing operation using the adhesive sheets twice and three times. In addition, there is a problem that a large amount of fine particle organic substances (hereinafter referred to as particles) derived from the resist material and the adhesive sheets remain on the substrate from which the resist material has been peeled off.

In view of the above-mentioned circumstances, the present invention simply and surely removes unnecessary resist film images on articles using adhesive sheets regardless of their types and properties.
It is also intended to prevent the particles from remaining on the article after the removal.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, have found that photocurable adhesive sheets containing a specific organic resin component in the adhesive layer. It was found that the use of the above-mentioned method provides high resist removability, the resist film image can be easily and surely removed, and the number of particles on the article can be reduced, and the present invention has been completed.

That is, according to the present invention, a photocurable adhesive layer is provided on a film substrate, and the above-mentioned adhesive layer contains an organic resin component having the same molecular skeleton structure as the resist material. The resist removing adhesive sheets (claims 1 to 5) and the resist removing adhesive sheet having the above-mentioned structure are pasted on an article having a resist film image. A method of removing resist, characterized in that after the adhesive sheets are photo-cured, the adhesive sheet and the resist material are integrally peeled off to remove the resist material on the article (claim 6). It is related to.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An adhesive sheet for resist removal according to the present invention
As the film base material, polyethylene,
A plastic film made of various plastics such as polypropylene, polyethylene terephthalate, acetyl cellulose and having a thickness of about 10 to 100 μm and capable of transmitting light such as ultraviolet rays is used.

Usually 10 to 180 μm is formed on the film base material.
A photo-curable adhesive layer of about m is provided to form a sheet-shaped or tape-shaped adhesive sheet for resist removal. In the present invention, by including an organic resin component having the same molecular skeleton structure as the resist material in the adhesive layer, regardless of the type and properties of the resist material, high resist removability and particle reduction effect can be obtained. Can be obtained. This is because the above organic resin component has excellent affinity with the resist material, and when it is attached onto the resist material, it is well integrated with the resist material and is photocured in this state. It seems that the resist removability and the particle reduction effect can be obtained.

The above-mentioned organic resin component having such an effect may be one having the same molecular skeleton structure as that of the resist material. For example, in the case of a resist material having a phenol resin as a molecular skeleton structure, When the phenol resin or its derivative is an acrylic resist material, an acrylic resin or its derivative is used.

More specifically, in the case of a resist material composed of a phenol novolak resin having an o-naphthoquinone diazide sulfonate as a photosensitive group, a phenol novolak resin having a molecular skeleton structure or an unsaturated double bond An allylphenyl etherified phenolnovolak resin introduced with is used. Further, in the case of a resist material composed of a cresol-novolak resin having 4- (2'-nitrophenyl) -2,4-dicarboxyester-3,5-dimethyl-1,4-dihydropyridine as a photosensitive group, its molecular skeleton structure is used. And the allylphenyletherified crezo-lunovolak resin obtained by introducing an unsaturated double bond into the resin. Furthermore, 2,6
In the case of a resist material composed of a cyclized polyisopropylene resin having di- (4′-azidobenzal) -4-methylcyclohexane as a photosensitive group, a cyclized polyisopropylene resin having a molecular skeleton structure is used.

Among the above organic resin components, when the resist material is a phenol novolak resin, it is preferable to use an organic resin component having the same phenol skeleton structure as the phenol novolak resin structure. Further, as the organic resin component having the same molecular skeleton structure as that of the resist material, it is also preferable to use one having a photopolymerizable unsaturated double bond such as allylphenyl ether introduced in its molecule. Further, as the organic resin component having the same molecular skeleton structure as that of the resist material, it is preferable to use an organic resin component having exactly the same constitution as that of the resist material.

The amount of such an organic resin component used is 3 to 200 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the high molecular weight polymer constituting the photocurable adhesive layer. Good. If the amount is too small, the above effect cannot be obtained. If the amount is too large, the resist removability and the effect of reducing particles are deteriorated, and in particular, the resist material may not be completely removed or the adhesive sheets may be cut off. There is.

The photo-curable adhesive containing such an organic resin component has pressure-sensitive adhesiveness in a normal state, has good affinity with the resist material on the article, and is irradiated with light such as ultraviolet rays to resist material. Any composition may be used as long as it can be integrally cured with, and its composition is not limited. Generally, a polymer containing a high molecular weight polymer having a weight average molecular weight of 10,000 to 2,000,000, a photopolymerizable compound and a photopolymerization initiator is preferably used.

As the high molecular polymer, any of various known polymers applied to pressure-sensitive adhesives can be used. If the molecular weight is lower than the above range, when peeling the adhesive layer and the resist material together, the film strength is not sufficient, so that breakage or cohesive failure may occur, and the resist material may be peeled sufficiently. difficult. Further, when the photopolymerizable composition is blended, the viscosity becomes low, and problems such as flowing during storage tend to occur. When the molecular weight is higher than the above range, handling problems are likely to occur. The high-molecular polymer preferably has a glass transition temperature of room temperature or lower in consideration of workability (removability) at the time of removing the resist, but may have a glass transition temperature higher than room temperature in some cases.

Among such high molecular weight polymers, as an acrylic polymer, a (meth) acrylic acid alkyl ester (acrylic acid or methacrylic acid and carbon number is usually 1) is used.
An ester with an alcohol of 2 or less) as a main monomer,
If necessary, a carboxyl group, a hydroxyl group or an amide group-containing monomer or other modifying monomer is added, and these monomers are solution-polymerized, emulsion-polymerized, suspension-polymerized by a conventional method,
An acrylic polymer obtained by polymerizing by a method such as bulk polymerization is preferably used.

Acrylic acid, methacrylic acid, itaconic acid and the like are used as the carboxyl group-containing monomer, and hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate are used as the hydroxyl group-containing monomer. As the amide group-containing monomer, (meth) acrylamide, N-vinylpyrrolidone, N, N-dimethylaminopropylacrylamide and the like are used, respectively. Examples of other modifying monomers include vinyl acetate, vinyl propionate, styrene, (meth) acrylonitrile, glycidyl methacrylate and the like.

The photopolymerizable compound is a non-volatile compound having at least one unsaturated double bond which can be cured by irradiation with light, and the term "non-volatile" as used herein means a process for manufacturing an adhesive, such as a coating process or a drying process. This means that the compound does not easily volatilize in the process and the like. The amount of the photopolymerizable compound used is usually 200 parts by weight or less per 100 parts by weight of the polymer. If this amount is used too much, the adhesive will flow out during storage,
Not preferred.

Examples of such a photopolymerizable compound include phenoxy polyethylene glycol (meth) acrylate, ε-caprolactone (meth) acrylate,
Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, urethane (meth) acrylate ─ To, epoxy (meth) acryl ─
And oligoester (meth) acrylates, and of these, one kind or two or more kinds are used.

The photopolymerization initiator is one which generates radicals upon irradiation with light such as ultraviolet rays, and any known photopolymerization initiator such as benzoin, benzoin ethyl ether and dibenzyl can be used. These photopolymerization initiators,
It is usually used in the range of 0.1 to 10 parts by weight per 100 parts by weight of the high molecular weight polymer.

The photocurable adhesive composed of these components is
0.05~1kg / mm ² elastic modulus before photocuring, so that the 1~500kg / mm ² after photocuring, desirably determine the kind and amount of each component. If the elastic modulus before photo-curing, that is, when attached is too small, the adhesive may flow out during storage, while if it is too large, the integration with the resist material during attachment becomes insufficient, resulting in poor resist removability. Cheap. Further, if the elastic modulus after photocuring is too small, the resist removability is inferior, and if it is too large, the adhesive layer is liable to be cut and the resist removability is also inferior.

In the resist removing method of the present invention, first, the adhesive sheet having the above-mentioned structure is attached to an article such as a semiconductor wafer having a resist film image, and the photocurable adhesive layer and the resist material are attached. Combine with. Here, since the adhesive layer contains an organic resin component having the same molecular skeleton structure as the resist material, the integration is easy. However, in order to further promote this integration, heating and / or pressure may be applied during application.
After this integration, ultraviolet rays are applied at an irradiation amount of about 300 to 3,000 mj / cm ² to photo-cure the adhesive and the adhesive sheet
The resist material on the article is removed by peeling the mold and the resist material together.

According to this removing operation, the image of the resist film on the article is irrespective of its kind or property, even when the resist material is degenerated due to ion implantation or the like, a part or a minute portion of the resist material. If it is not peeled off and remains on the article, there is no worry and it can be surely peeled off by a simple operation. Moreover, there is little concern that particles derived from the resist material or adhesive sheets will remain on the surface of the article from which the resist material has been peeled off, and the subsequent cleaning step is easy.

[0025]

Next, an embodiment of the present invention will be described in more detail. The resist film images A and B, which are the objects of peeling and removal in the examples, are formed on the semiconductor wafer by the methods of the following reference examples 1 and 2.

Reference Example 1 On the surface of a silicon wafer (5-inch semiconductor substrate), o
-A resist material made of a phenol novolak resin having naphthoquinone diazide sulfonic acid ester as a photosensitive group was applied, heated, exposed and developed to form it on the entire surface. After that, the acceleration energy of P ⁺ ions is −80 KeV.
Then, a total dose of 1 × 10 ¹⁶ ions / cm ² was injected. The image on the silicon wafer thus formed was used as a resist film image A.

Reference Example 2 A surface of a silicon wafer (5-inch semiconductor substrate) was coated with a resist material containing tetraethylene glycol diacrylate as a photosensitive group and polymethyl methacrylate as a main component, followed by heating, exposure and development. Was performed, and this was formed on the entire surface. Then, P ⁺ ions were implanted over the entire surface at an acceleration energy of 80 KeV and a dose amount of 1 × 10 ¹⁶ ions / cm ² . The image on the silicon wafer formed in this way,
The image is a resist film image B.

Example 1 100 g of a copolymer of methyl acrylate / butyl acrylate / hydroxyethyl acrylate = 61/30/9 (weight ratio) (weight average molecular weight: 570,000) and o-naphthoquinonediazide sulfonate were exposed to light. Polyphenol film having a thickness of 50 μm was prepared by adding 20 g of a phenol-novolak resin as a base (the same as the resist material used for forming the resist film image A), 75 g of polyethylene glycol diacrylate, and 2 g of a photopolymerization initiator in methyl ethyl ketone. It is applied on a film substrate consisting of
Dry at 0 ° C and 130 ° C for 3 minutes each to give a thickness of 40
A μm photocurable adhesive layer was formed to obtain a resist removing adhesive sheet.

Next, the above-mentioned adhesive sheet was attached to the resist film image A on the semiconductor wafer with a pressure roll under heating, and then 1 J / V of ultraviolet rays was applied by a high pressure mercury lamp.
Irradiation was carried out at a dose of cm ² to cure the adhesive sheet. After that, peel off the adhesive sheet and the image A,
The image A was removed from the wafer.

Example 2 100 g of a copolymer of acrylic acid / methyl acrylate / hydroxyethyl acrylate = 70/25/5 (weight ratio) (weight average molecular weight of 370,000), 15 g of allylphenyl etherified phenol novolak resin, An adhesive sheet for resist removal was prepared in the same manner as in Example 1 except that a solution of 100 g of polyethylene glycol dimethacrylate and 2 g of a photopolymerization initiator in ethyl acetate was used. Using this adhesive sheet, the resist film image A was peeled and removed in the same manner as in Example 1.

Example 3 100 g of a copolymer of methyl acrylate / butyl acrylate / hydroxyethyl acrylate = 61/30/9 (weight ratio) (weight average molecular weight 570,000) and tetraethylene glycol acrylate were exposed. Using a methyl ethyl ketone solution containing 60 g of an organic resin containing polymethylmethacrylate as a main component (the same as the resist material used to form the resist film image B), 30 g of pentaerythritol triacrylate, and 2 g of a photopolymerization initiator. Then, in the same manner as in Example 1 except for the above, an adhesive sheet for resist removal was produced. Also,
Using this adhesive sheet, the resist film image B was peeled off in the same manner as in Example 1.

Comparative Example 1 An adhesive sheet for resist removal was prepared in the same manner as in Example 1 except that the use of phenol-novolak resin having o-naphthoquinonediazide sulfonate as a photosensitive group was omitted. Also, using this adhesive sheet, Example 1
The resist film image A was peeled and removed in the same manner as in.

Comparative Example 2 An adhesive sheet for resist removal was prepared in the same manner as in Example 2 except that the use of allylphenyl etherified phenol novolak resin was omitted. Using this adhesive sheet, the resist film image A was peeled off in the same manner as in Example 2.

Comparative Example 3 An adhesive sheet for resist removal was prepared in the same manner as in Example 3 except that the organic resin containing tetraethylene glycol acrylate as a photosensitive group and polymethyl methacrylate as a main component was omitted. Was made. Using this adhesive sheet, the resist film image B was peeled off in the same manner as in Example 3.

With respect to the results of peeling and removing the resist film images A and B according to the above Examples 1 to 3 and Comparative Examples 1 to 3,
The resist removability was evaluated according to the following criteria. Also, as the number of particles on the surface of the semiconductor wafer after peeling and removal,
Using a laser surface inspection device [trade name "LS-5000" manufactured by Hitachi Electronics Engineering Co., Ltd.], the number of foreign matters of 0.2 μm or more attached to the wafer surface [5 inch wafer (1 wafer (123 cm ² wafer area)] Per] was counted and evaluated according to the following criteria.

<Resist Removability> A: No resist is recognized. A: Trace amount of resist is recognized. Δ: The resist is only partially removed. X: The resist is not removed at all.

<Number of particles> A: less than 100 B: 100 to 1,000 C: more than 1,000

[0038]

As is clear from the results of Table 1 above, by using the adhesive sheets of Examples 1 to 3 of the present invention,
Good results were obtained in the removability of the resist film images A and B, and the number of particles on the surface of the semiconductor wafer after peeling and removal was reduced.

[0040]

As described above, according to the present invention, as an adhesive sheet for resist removal, an organic resin component having the same molecular skeleton structure as the resist material is contained in the photocurable adhesive layer. The unnecessary resist film image on the article can be easily and reliably removed regardless of its type and properties, and the number of particles on the article can be removed after the removal. The effect is also reduced.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C09J 7/02 JLE C09J 7/02 JLE H01L 21/027 H01L 21/30 572Z (72) Inventor Koichi Hashimoto Osaka Prefecture 1-2 1-2 Shimohozumi, Ibaraki City Nitto Denko Corporation (72) Inventor Tatsuya Sekido 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (6)

[Claims] 1. A photocurable adhesive layer is provided on a film substrate, and the adhesive layer contains an organic resin component having the same molecular skeleton structure as the resist material. Characteristic adhesive sheet for resist removal. 2. The resist removing adhesive sheet according to claim 1, wherein the same molecular skeleton structure as the resist material is a phenol novolak resin structure. 3. The resist removal according to claim 1, wherein the organic resin component having the same molecular skeleton structure as the resist material has a photopolymerizable unsaturated double bond introduced into its molecule. Adhesive sheets for 4. The resist removing adhesive sheet according to claim 1, wherein the organic resin component having the same molecular skeleton structure as the resist material comprises an organic resin component having exactly the same constitution as the resist material. 5. The photocurable adhesive layer has a weight average molecular weight of 1.
1 to 2 million high molecular weight polymers, photopolymerizable compounds and photopolymerization initiators, and an organic resin component having the same molecular skeleton structure as the resist material. 4. The adhesive sheet for resist removal according to any one of 4 above. 6. The adhesive sheet according to any one of claims 1 to 5 is attached to an article having a resist film image, the adhesive sheet is photocured, and then the adhesive sheet is adhered. A resist removing method, characterized in that a sheet and a resist material are integrally peeled off to remove the resist material on an article.