JPH06252041A - Resist removal hardening liquid material and resist removal method - Google Patents

Abstract

PURPOSE:To remove easily a wafer on an article which is no more useful during the manufacture of electronic components, such as semiconductor or the preparation of a circuit without causing troubles that impurity ions contained in a resist material are implanted into a wafer or that a solvent damages a working environment. CONSTITUTION:The surface of an article on which there exists a resist pattern is coated with a hardening liquid material that contains a non-volatile low molecular weight substance which has at least one unsaturated double bond, and, which is in excellent affinity with a resist material as an essential ingredient and cured. After that process is over, the resist material with that hardened substance is separated in one piece.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable liquid material for removing a resist on an unnecessary article in the production of electronic parts typified by semiconductors and the production of circuits. The resist removal method that has been used.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a circuit is formed after a resist material is applied on a silicon wafer and exposed and developed in a predetermined pattern. After the circuit is formed, the resist material is removed, and in order to form the next circuit, a cycle of applying the resist material again is performed. Further, in order to form a circuit on various substrates, a resist pattern is usually formed. At this time, the unnecessary resist material is generally removed by an asher (ashing means) or a solvent.

[0003]

However, if the asher is used for removing the resist material, the work may take a long time and the impurity ions in the resist material may be implanted into the wafer. Further, use of a solvent causes a problem in the work environment.

In view of the above-mentioned conventional circumstances, the present invention is a curable liquid material for resist removal and a resist removal method which can simplify the step of removing the resist material and can solve the problems caused by impurity ions and solvent in the resist material. Is intended to provide.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above object. As a result, when a resist material is removed, a specific curable liquid material is used. According to the method of applying and curing, and then peeling the cured material and the resist material together, when the impurity ions in the resist material are injected into the wafer or the working environment is harmed by the solvent as in the conventional case. The inventors have found that the resist material can be easily removed without causing the above problems, and have completed the present invention.

That is, the first aspect of the present invention is to include, as an essential component, a non-volatile low molecular weight substance having one or more unsaturated double bonds in the molecule and having a good affinity with a resist material. The present invention relates to a curable liquid material for resist removal, characterized in that a nonvolatile low molecular weight material is an ether (meth) acrylate, an ester (meth) acrylate, a polyvalent alcohol. System (meth) acrylate,
Particularly, a constitution which is a urethane (meth) acrylate or an epoxy (meth) acrylate and a constitution which contains 0.1 to 10 parts by weight of a polymerization initiator per 100 parts by weight of a nonvolatile low molecular weight substance, This is a preferred mode.

A second aspect of the present invention is a method of removing a resist using the above-mentioned curable liquid material, which comprises applying the above-mentioned curable liquid material onto an article having a resist pattern and curing the same. , A resist removing method, characterized in that the cured product and the resist material are integrally peeled off,
In this method, it is particularly preferable that a peeling film base material is adhered to the coating surface of the curable liquid material before or after the curing, and the cured product and the resist material are integrally peeled together with the base material. It is set as an aspect.

[0008]

The curable liquid material for resist removal according to the present invention comprises a nonvolatile low molecular weight substance as an essential component, a polymerization initiator is usually added thereto, and if necessary, a high molecular weight polymer, oligomer or A material that is liquid at room temperature and contains a monomer, and if desired, a filler, various stabilizers, a colorant, a solvent, etc., and is applied to an article having a resist pattern, and then the resist pattern. A part thereof is fluidly permeated into the concave portion of the resin or permeated into the resist material itself to be integrated with the resist material, and then cured by heating or irradiation with active energy rays.

The non-volatile low molecular weight compound has at least one unsaturated double bond in the molecule involved in the curing reaction such as polymerization and crosslinking, and has a good affinity with the resist material.
In other words, it is necessary that the wettability with respect to the resist material is good, the compatibility and the permeability are excellent, and that the non-volatile material does not easily volatilize in the coating and drying step. Of these, those having excellent storability and uniform coating property are preferably used. As for the molecular weight,
Weight average molecular weight is usually 5,000 or less, preferably 15
It is about 0 to 2,000.

As such a nonvolatile low molecular weight compound,
Phenoxy polyethylene glycol (meth) acrylate
Polyethylene glycol (meth) acrylate,
Polyether glycol (meth) acrylate and other ether type (meth) acrylates; oligoester (meth) acrylate and ε-caprolactone (meth) acrylate and other ester type (meth) acrylates Trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and other polyvalent alcohol-based (meth) acrylates; urethane-based (meth) acrylates; epoxy-based (Meth) acrylic
And the like, and of these, one or two of them
More than one seed is used.

The content of the non-volatile low molecular weight substance is usually 20% by weight or more, preferably 40% by weight or more based on the entire curable liquid material. If the amount used is too small,
It is not preferable because the curability due to heating or irradiation with active energy rays is impaired and the affinity with the resist material is impaired.

The polymerization initiator is used to accelerate the curing reaction due to the polymerization and crosslinking of the non-volatile low molecular weight substance. For example, in the case of heat curing, it is heated by heating benzoylperoxide, azobisisobutyronitrile or the like. A thermal polymerization initiator that generates radicals is used, and in the case of photocuring with ultraviolet rays, a photopolymerization initiator that generates radicals by light irradiation such as benzoin, benzoin ethyl ether, and dibenzyl is used. These polymerization initiators are usually used in a proportion of 0.1 to 10 parts by weight per 100 parts by weight of the nonvolatile low molecular weight substance.

The high molecular weight polymer has a viscosity of a liquid material,
It is for adjusting wettability to resist materials, coating workability, etc., and increasing the strength of the cured product to surely and easily remove it, and has excellent compatibility with non-volatile low molecular weight substances. Is used. An acrylic polymer is particularly preferable as such a polymer, but other styrene-isoprene-styrene block copolymers (SI
S), various elastomers such as styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-butadiene-styrene block copolymer (SBS) and ethylene-vinyl acetate copolymer (EVA). Good.

The acrylic polymer comprises an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester, that is, an ester of acrylic acid and / or methacrylic acid and an alcohol having a carbon number of usually 12 or less as a main monomer, If necessary, vinyl acetate, vinyl propionate, styrene, acrylonitrile, acrylamide,
Modifying monomers such as glycidyl methacrylate, acrylic acid, methacrylic acid, and hydroxyethyl acrylate are added in a proportion not exceeding 50% by weight based on the total amount of all monomers, and these are subjected to solution polymerization by a conventional method. It is obtained by polymerizing by a method such as emulsion polymerization, suspension polymerization and bulk polymerization.

The weight average molecular weight of the acrylic polymer is usually 100,000 to 2,000,000. If the molecular weight is too low, the strength of the cured product will not increase during peeling, and if it is too high, the coating workability will deteriorate. Further, the acrylic polymer preferably has a glass transition point of 270 ° K or lower in consideration of workability at the time of peeling the resist. If it is higher than this, it becomes too hard after curing and the peeling becomes heavy, which is not preferable. Further, this acrylic polymer may be introduced with an unsaturated bond in its molecule so that it is simultaneously involved in the curing reaction at the time of polymerization and crosslinking of the nonvolatile low molecular weight substance.

The amount of the high molecular weight polymer used is usually 50% by weight or less of the entire liquid material in consideration of the molecular weight, the glass transition point, the physical properties of the cured product, etc. within a range that does not impair the fluidity of the liquid material. It is good to say If the amount is too large, the work of peeling the cured product and the resist material together may be hindered.

The oligomer is a low molecular weight substance which is liquid at room temperature and is used for almost the same purpose as the above high molecular weight polymer.
That is, the weight average molecular weight is usually less than 100,000, preferably about 2,000 to 50,000. As this oligomer, an acrylic oligomer having excellent compatibility with a non-volatile low molecular weight substance, which is obtained by adjusting the molecular weight of the chain transfer agent in the same manner as the acrylic polymer, is preferable. Besides, liquid polybutadiene, liquid polyisoprene and the like can also be used.

The amount of the oligomer used is the high molecular weight polymer.
In the same manner as in the above case, considering the molecular weight, the glass transition point, the physical properties of the cured product, etc., it is usually preferable to set it to 50% by weight or less of the entire liquid material. It is also possible to introduce an unsaturated double bond into the molecule of an acrylic oligomer or the like to cause a curing reaction simultaneously with the polymerization and crosslinking of the unsaturated low molecular weight compound. In this case, 80 weight% of the entire liquid material is used. It may be used up to%.

In addition to the above-mentioned high molecular weight polymer and oligomer, a monomer may be added to the curable liquid material of the present invention as an optional component. Is used for the purpose of adjusting the viscosity of, and particularly preferably, isobornyl acrylate,
Low-odor (meth) acrylates such as tetrahydrofurfuryl acrylate and phenoxyethyl acrylate
Monomers are selectively used. The amount used is preferably 20% by weight or less based on the whole liquid material.

In the method of removing the resist of the present invention, first, the above-mentioned curable liquid material is applied to the article having the resist pattern by an appropriate means. The coating amount is such that the thickness after curing is usually 20 μm or more, preferably 40 μm.
It is preferable that the thickness is about 150 μm. Too thin,
The strength of the cured product cannot be obtained sufficiently.

By such application, the liquid material partially flows and permeates into the concave portion of the resist pattern, and also permeates into the resist material itself to be integrated with the resist material. To promote this integration, heating or pressurizing means may be added after coating, if necessary. When the liquid material contains an organic solvent or water, in order to volatilize and remove these media,
Heat appropriately and dry.

After being coated in this manner, the liquid material and the resist material are integrally cured by heating or irradiation with active energy rays by utilizing the unsaturated double bond of the non-volatile low molecular weight material. From the standpoint of workability, curing by irradiation with light such as ultraviolet rays is desirable. The irradiation amount of ultraviolet rays is usually about 300 to 3,000 mj / cm ² .

By this curing treatment, the adhesive force between the resist material and an article such as a wafer is also reduced. When the cured product is peeled off in this state, the cured product and the resist material are integrated and easily peeled and removed from the article. When the peeling cannot be completed completely by one operation, the above-mentioned application-curing-peeling operation may be repeated. According to this method, there is no need to worry about the work being performed for a long time as in the conventional method using an assuring method, and when impurity ions in the resist material are implanted into the wafer, there is no need to worry about the work in the conventional method using a solvent. There is no need to worry about the deterioration of the environment.

In the above peeling operation, when the strength of the cured product itself is weak, in order to facilitate the peeling operation, the liquid material may be coated on the coated surface before or after the curing.
A peeling film base material may be attached and reinforced, and the cured product and the resist material may be integrally peeled together with the base material. Adhering before curing has the effect of preventing the substrate from inhibiting curing by oxygen in the air, and is particularly preferable. In the case of sticking after curing, it is preferable to select and use a liquid material whose cured product exhibits an adhesive force.

As the peeling film base material, a resin film having a reinforcing function and a thickness of about 15 to 100 μm is usually used. Especially when it is attached before curing, it is cured by irradiation with light such as ultraviolet rays. At this time, a polyethylene film, a polypropylene film, a polyethylene terephthalate film or the like is preferably used as the resin film having excellent light transmittance.

[0026]

As described above, according to the present invention, a resist on an article such as a wafer is coated with a specific curable liquid material and cured, and then the cured product and the resist material are integrally separated. Since it is operated, the purpose of removing the resist can be easily achieved without causing any problems when the impurity ions in the resist material are implanted into the wafer or when the working environment is damaged.

[0027]

EXAMPLES Next, examples of the present invention will be described to explain more specifically. In the following, "parts" means "parts by weight".

EXAMPLE 1 A monomer mixture consisting of 75 parts of 2-ethylhexyl acrylate, 20 parts of methyl acrylate and 5 parts of acrylic acid was added to 150 parts of ethyl acetate and 0.4 parts of 4,4'-azobisisobutyronitrile. Solution polymerization was carried out at 65 ° C. for 12 hours under a nitrogen stream with 3 parts to give a weight average molecular weight of 350,000.
A solution of an acrylic polymer having a glass transition point of 229 ° K was obtained.

To 200 parts of this acrylic polymer solution, 100 parts of urethane acrylate (trade name UA-101H manufactured by Kyoeisha Yushi-Kagaku Kogyo Co., Ltd.) and 3 parts of benzyl dimethyl ketal were uniformly mixed. To obtain a curable liquid material.

Next, the above-mentioned curable liquid material is applied on the pattern of a resist composed of novolak and quinonediazide applied to the surface of a silicon wafer, exposed and developed so that the thickness after curing becomes 30 μm. After that, it was dried to volatilize and remove the solvent in the coating liquid. Then, a polyethylene terephthalate film having a thickness of 25 μm is attached to this coated surface, and then ultraviolet rays are irradiated with a high pressure mercury lamp at an irradiation dose of 1,000 mj / cm ² to cure the liquid material. It was

After this curing treatment, when the polyethylene terephthalate film was peeled off and operated, the above resist was peeled off together with the above cured film together with the cured product. The surface of the silicon wafer was observed with a fluorescence microscope, but no resist material was found.

Comparative Example 1 The acrylic polymer solution of Example 1 was used as a liquid material as it was. Using this material, in the same manner as in Example 1, a resist pattern on the surface of a silicon wafer was coated and dried, and a polyethylene terephthalate film was attached and a curing treatment by ultraviolet irradiation was carried out to obtain the above film. It was peeled off. However, the resist material is
The surface properties were only destroyed due to the influence of the solvent in the liquid material, and almost all of it remained on the surface of the silicon wafer along with the dried material (not cured) of the liquid material applied on top of it, and peeling and removal. I couldn't do it.

Example 2 60 parts of 2-ethylhexyl acrylate, 30 parts of butyl acrylate, 5 parts of vinyl acetate, 3 parts of acrylic acid, 2 parts of 2-hydroxyethyl acrylate, 2-mercaptoethano-
A monomer mixture consisting of 1 part was placed in a flask, the atmosphere was replaced with nitrogen, and the mixture was heated to 70 ° C., to which 0.1 part of 4,4′-azobisisobutyronitrile was added. Polymerization was carried out until it disappeared to obtain an acrylic oligomer having a weight average molecular weight of 18,000 and a glass transition point of 207 ° K.

To this acrylic oligomer, 2 parts of 2-isocyanatoethyl methacrylate and 0.002 part of dibutyltin dilaurate were added, and the mixture was reacted at 50 ° C. for 3 hours to give a copolymer molecule. An unsaturated double bond was introduced. To 100 parts of this acrylic oligomer, 100 parts of oligoester acrylate (trade name Aronix M-5300 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and 5 parts of benzyl dimethyl ketal are uniformly mixed and cured. A mold liquid material was prepared.

This curable liquid material was applied onto a resist pattern on the surface of a silicon wafer in the same manner as in Example 1, a polyethylene terephthalate film was attached, and a curing treatment by ultraviolet irradiation was performed. When the film was peeled off, the resist was peeled off together with the cured film together with the cured product. The surface of the silicon wafer was observed with a fluorescence microscope, but no resist material was found.

Example 3 10 parts of the polymer obtained by removing the solvent from the solution of the acrylic polymer of Example 1 and the acrylic oligomer of Example 2
40 parts, and polyethylene glycol diacrylate 40
Part, 10 parts of isobornyl acrylate, and 3 parts of benzyl dimethyl ketal were uniformly mixed to prepare a curable liquid material.

This curable liquid material was applied onto a resist pattern on the surface of a silicon wafer in the same manner as in Example 1, and a polyethylene terephthalate film was attached and a curing treatment by ultraviolet irradiation was performed. When the film was peeled off, the resist was peeled off together with the cured film together with the cured product. The surface of the silicon wafer was observed with a fluorescence microscope, but no resist material was found.

Claims (5)

[Claims] 1. A resist-removing agent, which comprises a non-volatile low-molecular weight substance having one or more unsaturated double bonds in the molecule and having a good affinity with a resist material as an essential component. Curable liquid material. 2. A non-volatile low-molecular weight substance is an ether type (meth) acrylate, an ester type (meth) acrylate,
The curable liquid material for resist removal according to claim 1, which is a polyvalent alcohol (meth) acrylate, a urethane (meth) acrylate or an epoxy (meth) acrylate. 3. The curable liquid material for resist removal according to claim 1, comprising 0.1 to 10 parts by weight of a polymerization initiator per 100 parts by weight of the nonvolatile low molecular weight substance. 4. An article on which a resist pattern is present,
A resist removing method comprising: applying the curable liquid material for resist removal according to claim 1 to 3 and curing the curable liquid material; and then, integrally separating the cured product and the resist material. 5. A peeling film base material is adhered to the coated surface of a curable liquid material for resist removal before or after the curing, and a cured product and a resist material are integrally peeled together with the base material. Item 4. The resist removal method according to Item 4.