JP3467124B2 - Adhesive sheets for resist removal and resist removal method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist film image, that is, a resist film image, in the step of forming a fine pattern in the manufacturing stage of finely processed parts such as semiconductors, circuits, various printed boards, various masks and lead frames. The present invention relates to a resist removing adhesive sheet for removing an image made of a resist material, and a resist removing method using the same.

[0002]

2. Description of the Related Art In recent years, lithography using a resist has been performed.
The process is used in various fields. In this lithographic process, after removing a part of the resist applied on the substrate etc. by development, the removed part or the remaining part is appropriately processed to add a desired function to the corresponding part of the substrate. The purpose is to remove the resist after the addition of this function is completed.

For example, in the manufacture of a semiconductor integrated circuit device, a resist material is applied onto a semiconductor substrate such as a silicon wafer, and a predetermined resist film image (resist pattern) is formed by a normal photo process. Using this as a mask, for example, various treatments such as ion implantation of P ⁺ , B ⁺ , As ^+, etc., and other etching are performed on the openings. At this time, the ions are also injected into the upper surface layer of the resist film image. After that, the unnecessary resist film image is removed, and a predetermined circuit is formed. Then, in order to form the next circuit, the cycle of applying the resist material again is repeated. Also, when circuits are formed on various substrates, unnecessary images are removed after image formation.

At this time, the unnecessary resist film image is removed by a method using ashing means (ion-assisted etching), a solvent (stripping solution) or a chemical. However, in the ashing means, the impurity ions in the resist material and the implanted ions remain on the semiconductor substrate and are introduced into the semiconductor substrate by the subsequent heat treatment, making it impossible to construct the semiconductor integrated circuit as designed, There is a problem of deteriorating the characteristics of the semiconductor device. Further, when oxygen plasma is used as the ashing means, it may cause damage to the semiconductor substrate, which causes a problem of degrading the reliability of the semiconductor device.

Further, the solvent (release solution) and Uetsuto cleaning method with chemicals in (wet process), the prevention of back contamination by a liquid for use management, time consuming, etc. Disposal of the liquid after use, in particular, NH ₄ OH / APM with H ₂ O ₂ / H ₂ O mixture
There is also a problem that the Si substrate is etched during cleaning, and its improvement is desired.

In order to solve such a problem, recently, in JP-A-4-345015 and JP-A-5-275324, adhesive sheets are attached to the upper surface of a resist film image, and the adhesive sheet is attached. A so-called sheet method has been proposed in which the sheets and the resist film image are separated and removed together. Since this sheet method does not have the problems of the above-described ashing means and wet cleaning method, it has attracted attention as a new method for removing a resist film image, and its practical application is under consideration.

[0007]

However, in this sheet construction method, the impurities in the adhesive sheet diffuse into the resist film and are transferred to the substrate surface, or the adhesive sheet directly contacts the substrate surface. In the part (the part where the resist material does not exist), there is a problem that the impurities in the adhesive are directly transferred to the surface of the substrate. That is, this transfer contains a metal such as an alkali metal, an alkaline earth metal, a transition metal, or antimony, and if these metals remain on the substrate surface even after the process is completed, for example, in a semiconductor device, Problems such as leakage and shortening of the charge retention time of the DRAM occur. The light metal can be relatively removed by performing RCA cleaning or the like after the sheet construction method, but a slight amount of transition metal or the like is extremely difficult to remove, and the above problems cannot be solved.

In view of such circumstances, the present invention provides an adhesive sheet for peeling and removing an unnecessary resist film image on an article such as a silicon wafer using adhesive sheets.
The purpose of this is to prevent impurities in the group from being transferred to the surface of an article such as a wafer and causing problems such as yield of the article and deterioration of reliability due to electrical failure.

[0009]

DISCLOSURE OF THE INVENTION As a result of earnest studies for the above-mentioned objects, the present inventors found that not only impurities originally transferred to a wafer or the like were originally contained in the adhesive. However, the impurities contained in the base material may diffuse and migrate into the pressure-sensitive adhesive, or when a separator is attached, the phenomenon that the impurities diffuse and migrate from the separator into the pressure-sensitive adhesive is also observed. It has been clarified that impurities existing in a base material or an adhesive transfer to an article surface such as a wafer when the separator is peeled off and attached to a wafer or the like, which causes the above problems.

In particular, impurities contained in the base material, the separator, and the like are produced by using a metal element such as antimony or a compound thereof as a polymerization catalyst when synthesizing a resin as a material for these, for example, a polyester resin. Therefore, it was also clarified that these metal elements are usually mixed in the sheet in a unit of about 100 ppm, and this causes diffusion and transfer to the adhesive, and eventually transfer to the wafer surface and the like.

Based on these findings, the inventors of the present invention, when synthesizing a polyester resin or the like, elements such as carbon, silicon, which form a diamond type lattice as a crystal structure,
By using a periodic group 14 element such as germanium or tin or a compound thereof as a polymerization catalyst, the amount of other metal elements such as antimony in a base material or a separator made of this resin is reduced, Similarly, by providing an adhesive with a reduced amount of other metal elements such as antimony,
Adhesive sheets were prepared.

When this adhesive sheet is pasted on an article such as a wafer having a resist film image and subjected to a peeling treatment, the amount of metal elements such as antimony transferred to the surface of the article such as the wafer is reduced, and the polymerization is performed. Since the Group 14 element of the periodic law used as a catalyst is an element having a low electric activity, it does not cause an electrical obstacle to a wafer or the like even if it is transferred onto an article such as a wafer, and the article after the resist is peeled off is removed. Found that the yield and reliability of
The present invention has been completed.

That is, according to the present invention, in an adhesive sheet for peeling and removing a resist film image existing on an article, an adhesive is provided on a substrate, and a separator is provided on the surface of the adhesive as required. The amount of the electrically active metal element other than the periodic group 14 element contained in the pressure-sensitive adhesive and the base material of the pressure-sensitive adhesive in a state where the separator is peeled off at the time of use is an individual element 20ppm in terms of metallic elements
The present invention relates to a resist removing adhesive sheet characterized by the following:

The present invention also provides a resist removing method in which the above-mentioned adhesive sheets are adhered onto an article having a resist film image and the resist film image and the resist sheet image are integrally peeled and removed. - periodic transcribed from bets such on an article first
An electrically active metal element other than the group 14 element and its compound have an atomic number density of each element of 5 × 10 ¹⁰ atom.
/ Cm ² or less, the present invention relates to a method of removing a resist.

[0015]

DETAILED DESCRIPTION OF THE INVENTION Adhesive sheets according to the present invention are as follows:
An adhesive layer having a thickness of about 10 to 200 μm is provided on a base material to obtain a sheet-like or tape-like form . It is characterized in that the amount of the electrically active metal element other than the group 14 element and the compound thereof is 20 ppm or less in terms of the metal element of each element. When the separator is attached to the pressure-sensitive adhesive surface, the amount of the electrically active metal element and its compound contained in the base material and the pressure-sensitive adhesive in the state where the separator is peeled off during use is the above-mentioned. It is characterized by the same value.

Here, the electrically active metal element and the compound thereof mean the electrically active metal element and the compound thereof except the periodic group 14 elements such as carbon, silicon, germanium and tin. This includes not only metals such as alkali metals, alkaline earth metals and antimony, but also many metal elements such as copper, zinc, titanium and manganese, as well as compounds of these with non-metal elements and organic substances. . Further, “20 ppm or less” defined as the content of these metal elements and their compounds is expressed in terms of metal elements for each of the above elements. Nao
In addition, in the present specification, the “periodic group 14 element” means
How to display the revised IUPAC Inorganic Chemistry Nomenclature (1989)
It is based on the law.

In order to set the content of the electrically active metal element and its compound to the above values, the base material and the separator are
Examples of the resin include a resin polymerized by using a metal element having a low electrical activity or a compound thereof as a catalyst, for example, a polyester resin such as polyethylene terephthalate polymerized by using a compound of a periodic group 14 element such as germanium as a catalyst. The film consisting of is preferred. A cloth woven from quartz glass fibers, paper, etc., which are set to the above values, are also preferable. Of course, the material is not particularly limited, and a base material or a separator made of various materials may be used as long as the above content is set to the above value.

The same applies to the pressure-sensitive adhesive provided on the substrate, as long as the content of the electrically active metal element and its compound is the above value as the total amount with the substrate, it is conventionally known. It can be widely used. Generally, a resist-penetrating component, if necessary, in an adhesive polymer having a reduced content of the above metal element and its compound,
A pressure-sensitive adhesive obtained by adding a crosslinking agent and other compounding agents is used.

Various kinds of tacky polymers can be used, but acrylic polymers containing acrylic acid or acrylic acid alkyl ester and / or methacrylic acid alkyl ester as a main monomer are preferable. This acrylic polymer is obtained by using the above-mentioned main monomer, optionally a monomer containing a carboxyl group or a hydroxyl group, and other modifying monomers, and solution-polymerizing them by a conventional method.
It is obtained by polymerizing by a method such as emulsion polymerization, suspension polymerization and bulk polymerization.

Examples of the above-mentioned carboxyl group-containing monomer include methacrylic acid, maleic acid and itaconic acid, and examples of the hydroxyl group-containing monomer include hydroxyethyl acrylate and hydroxypropyl acrylate. . Other modifying monomers include vinyl acetate, vinyl propionate, styrene, acrylonitrile, acrylamide, glycidyl methacrylate, and the like. The amount of these reforming monomers to be used is usually preferably 50% by weight or less in the total amount with the above-mentioned main monomers.

In the above-mentioned polymerization, the chemicals used in the process of synthesizing the polymerization catalyst, salt for salting out, etc. are the same as in the case of the resin synthesis for the base material and the separator as described above. Use of compounds or non-metal compounds,
Periodic law of germanium, which is an electrically inactive element
It is desirable to prevent the mixture of the electrically active metal element into the acrylic polymer as much as possible by using the compound of the group 14 element. When the active metal element is unavoidably used, it is necessary to finally perform a sufficient purification and removal operation.

The average molecular weight of the acrylic polymer thus obtained is usually 1,000 to 200 on a weight average basis.
It should be ten thousand. If the molecular weight is too low, the viscosity of the adhesive will be low, which may cause inconvenience such as flowing during storage. If the molecular weight is too high, handling problems will easily occur, which is not preferable.

The resist-penetrating component, which is optionally added to the tacky polymer such as the acrylic polymer, has the property of migrating or diffusing into the resist material to dissolve or swell the resist material. Is something
As a measure of the above properties, a resist material sufficiently dried with a solvent is dipped in this resist penetrating component, for example, 1
When stored at 30 ° C for 24 hours, the resist material dissolves,
Any material having a property of swelling or breaking may be used.

Such resist-penetrating components include alcohols, ketones, esters, and C _n H _2n O groups (H may be substituted with elements such as C and O). , A substance having a pentaerythritol group, and the like.
For example, as the alcohols, methyl alcohol,
Ethyl alcohol, hexyl alcohol, dodecyl alcohol and the like, ketones such as acetone, ethyl methyl ketone and dihexyl ketone, and esters such as ethyl acetate, ethyl propionate and ethyl butyrate. Can be mentioned.

As the substance having a C _n H _2n O group, ethylene glycol, propylene glycol, neopentyl glycol, hexanediol, decanediol, octadecanediol, polyethylene glycol, polypropylene Glycol, methoxy (poly) ethylene glyco
, Methoxy (poly) ethylene glycol, protoxy (poly) ethylene glycol, butoxy (poly) ethylene glycol, phenoxy (poly) ethylene glycol,
Glycerin, diglycerin, polyglycerin, methyl-
Butanol, hexane triol, dimethyl hexane triol, isopropyl-oxymethyl-propanediol, hexane tetrol, hexene tetro
Le, tarits, sorbits, etc.

Other substances having a C _n H _2n O group include
Dicetyl ether, bishydroxy (poly) ethoxyphenyl-propane, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene polyoxypropylene block polymer -, Sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamine ethers, fatty acid diethanolamides, polyoxyethylene lanolin fatty acid esters and the like.

Examples of the substance having a pentaerythritol group include pentaerythritol and dipentaerythritol.
Le, pentaerythritol-Luzteareto, etc.,
Pentaerythritol tetrapolyethylene glycol,
Examples thereof include ethylene oxide adducts such as pentaerythritol tetrapolypropylene glycol, propylene oxide adducts and butylene oxide adducts.

These resist-penetrating components are usually used in a proportion of 1 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the adhesive polymer. If the amount used is too small, the effect of increasing the peelability of the resist film image due to migration and diffusion to the resist material becomes small, and conversely if too much is used, the resist is removed when it migrates to the resist material and diffuses. Once dissolved, the shape of the resist film image is lost, and foreign substances are likely to remain after removing the image, which is not preferable.

The cross-linking agent added to the tacky polymer crosslinks the tacky polymer to increase cohesive force and gives good results in workability in attaching to a resist film image.
For example, a polyisocyanate compound, a melamine compound, a polyepoxy compound, various metal salts, and a chelate are used as polyfunctional compounds that react with the above-mentioned functional groups in an acrylic polymer obtained by copolymerizing a carboxyl group- or hydroxyl group-containing monomer. It is possible to crosslink the polymer by blending a polymer compound or the like and promoting the reaction in the molding step such as a sheet.

The amount of such a crosslinking agent used is usually 20 parts by weight or less with respect to 100 parts by weight of the adhesive polymer. If the amount of the cross-linking agent used is too large, components that do not participate in cross-linking migrate to the surface of the semiconductor substrate where the resist does not exist, and this remains as particles and remains unpreferable.

As a compounding agent other than the cross-linking agent compounded in the pressure-sensitive adhesive, a filler such as finely divided silica can be mentioned, which is used for almost the same purpose as the cross-linking agent. In addition, various compounding agents such as a tackifier, a colorant, and an anti-aging agent may be added. These compounding agents are used in usual amounts.

The pressure-sensitive adhesive containing such a compounding component is preferably a curable pressure-sensitive adhesive in order to obtain a better release effect. In this case, usually, in addition to the above-mentioned components, a curable compound and a polymerization initiator as a curing catalyst are added. Further, in the photo-curing type, from the viewpoint of preventing a polymerization reaction due to heat, as a polymerization inhibitor, for example,
Hydroquinone, benzoquinone, butylcatechol, tri-p-nitrophenylmethyl and the like can also be added.

The curable compound is a compound having one or more unsaturated double bonds in the molecule and has a molecular weight of usually 10,
It is preferably 000 or less, and more preferably 5,0 so that the three-dimensional reticulation of the pressure-sensitive adhesive at the time of curing can be efficiently performed.
It preferably has a molecular weight of 00 or less. Further, it is desirable that a part or all of the curable compound is resist permeable, and in this case, a part or all of the resist permeable component may be replaced with the curable compound. .

As the resist penetrative curable compound,
Resist penetration above exemplified as component C _n H _2n O groups substance or pentaerythritol having a - further substances with Le group (meth) acrylate - like material obtained by introducing a preparative group. For example, polyethylene glycol (meta)
Acrylate and Pentaerythritol-Lutri Acrylate-
Pentaerythritol-tetratetraacrylate, dipentaerythritol-monohydroxypentaacrylate,
Dipentaerythritol-hexaacrylate, Dipentaerythritol-l-tetraacrylate, Dipentaerythritol-hexa-5-hydroxycaproate
And ethylene oxide adducts, propylene oxide adducts, butylene oxide adducts, and the like.

Examples of the curable compound include, in addition to the above-mentioned resist-penetrating compounds, for example, trimethylolpropane triacrylate, tetramethylmethanetriacrylate, and tetramethylmethanetetraacrylate.
Door, usually of hardness such as the commercially available oligoester acrylate Les ─ door
Chemical compounds may be used. In addition, Japanese Patent Publication 5-259
No. 07 (particularly, in the section of the prior art), and other polyorganosiloxane compositions, as well as the following polyol compounds, polyvalent isocyanate compounds, hydroxy (meth) acrylates, etc. It is also possible to use a urethane acrylate-based oligomer that is used.

Examples of the above-mentioned polyol compounds include ethylene glycol, propylene glycol, diethylene glycol, butanediol, pentanediol, trimethylolethane, trimethylolpropane, pentaerythritol and the like. To be Further, as the polyvalent isocyanate compound, there are toluene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate.
, Dimethyl diphenyl diisocyanate, dimethyl diphenyl diisocyanate, dicyclohexyl methane diisocyanate, xylene diisocyanate and the like. Further, examples of the hydroxy (meth) acrylate include 2-hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylate, pentaerythritol lute triacrylate and the like.

These curable compounds are adhesive polymers.
5 to 150 parts by weight, preferably 10 to 120 parts by weight, and more preferably 20 to 1 part by weight with respect to 100 parts by weight.
It is preferable to use it in an amount of 00 parts by weight. If this amount is too small, the peeling effect of the resist material may not be sufficient, and if it is too large, the pressure-sensitive adhesive may flow out during storage, which is not preferable.

In the case of thermosetting, a thermal polymerization initiator such as benzoylperoxide or azobisisobutyronitrile which generates a radical by heating is used as the polymerization initiator as a curing catalyst. In the case of photocuring with ultraviolet rays, benzoin, benzoin ethyl ether, dibenzyl, isopropyl benzoin ether, benzophenone, Michler's ketone chlorothioxanthone, dodecyl thioxanthone, dimethylthioxanthone, acetophenone diethyl ketal, Benzyl dimethyl ketal, α
A photopolymerization initiator such as -hydroxycyclohexylphenyl ketone or 2-hydroxymethylphenylpropane is used. The amount used is usually 0.5 to 15 parts by weight with respect to 100 parts by weight of the adhesive polymer.

In the present invention, an adhesive sheet composed of such a base material and an adhesive is used, and when this is attached to the adhesive surface, a separator is used.
After peeling off the resist film, it is attached to an article such as a semiconductor substrate having a resist film image, and the resist film image and the adhesive are integrated. In order to promote this attachment and integration, it is preferable to apply heat and / or pressure during the attachment.

Next, when the pressure sensitive adhesive sheet is made of a curable pressure sensitive adhesive, a predetermined curing treatment is performed by heating or light irradiation. At this time, a curing treatment by light irradiation is particularly suitable in consideration of a thermal influence on an article such as a semiconductor substrate, and the irradiation amount thereof is 300 to 2 for ultraviolet rays.
The range is preferably 10,000 mj / cm ² . In addition,
In the case of carrying out curing by such light irradiation, a base material that transmits light such as ultraviolet rays in advance is selected and used as the base material.

When the adhesive sheet and the resist film image are integrally peeled after the attachment and the required curing treatment as described above, the image is easily removed from the article. Here, the amount of the electrically active metal element other than the periodic group 14 element included in the adhesive sheet and the compound thereof is 20 ppm or less in terms of the metal element of each element. The amount of the metal element and its compound transferred to the article surface after resist removal is 5 in terms of atomic number density of each element.
It can be suppressed to × 10 ¹⁰ atom / cm ² or less. Therefore, no electric damage is caused to the article such as the semiconductor substrate, and good results are obtained in improving the yield and reliability in manufacturing the article.

[0042]

INDUSTRIAL APPLICABILITY As described above, the adhesive sheet for resist removal and the resist removing method of the present invention are used for producing finely processed parts such as semiconductors, circuits, various printed boards, various masks, and lead frames. It is used for removing the resist film image in the step of forming a fine pattern in a step, and the image can be easily and surely peeled off and removed, and on the article surface such as a semiconductor substrate from which the image is removed. It is possible to improve the yield and reliability without concern that impurities in the adhesive sheets are transferred and cause problems such as yield and reliability deterioration of articles due to electrical failure.

[0043]

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

Example 1 As a base material, a film A having a thickness of 50 μm and made of polyethylene terephthalate synthesized by using a germanium-based polymerization catalyst was used, and an acrylic polymer A was placed on the film A.
An acrylic pressure-sensitive adhesive solution a consisting of 100 parts, 70 parts of polyethylene glycol acrylate (molecular weight 308), 3 parts of polyisocyanate compound and 3 parts of α-hydroxycyclohexyl phenyl ketone was dried to a thickness of 30 μm.
Then, the adhesive sheet for resist removal was prepared by coating and drying so as to obtain m.

Example 2 Instead of the acrylic adhesive solution a, an acrylic polymer was used.
Example 1 except that an acrylic adhesive solution b consisting of 100 parts B, 50 parts polyethylene glycol acrylate (molecular weight 708), 3 parts polyisocyanate compound and 3 parts α-hydroxycyclohexyl phenyl ketone was used. Similarly, an adhesive sheet for resist removal was prepared.

Example 3 Instead of the acrylic pressure sensitive adhesive solution a, an acrylic polymer was used.
Acrylic adhesive solution c consisting of 100 parts of C, 50 parts of dipentaerythritol hexa-5-hydroxycaproate acrylate, 3 parts of polyisoane compound and 3 parts of α-hydroxycyclohexylphenyl ketone was used In the same manner as in Example 1, an adhesive sheet for resist removal was produced.

Example 4 As a separator, a separator A prepared by treating one side of the polyethylene terephthalate film A used as the base material in Example 1 with silicon was used. This separator A was used as an example. By sticking to the adhesive surface of the adhesive sheet prepared in 1 above, a resist removing adhesive sheet with a separator was obtained.

Comparative Example 1 As a base material, a film B made of polyethylene terephthalate synthesized using an antimony-based polymerization catalyst and having a thickness of 50 μm was used, and on top of this, the acrylic adhesive solution of Example 1 was used. A was applied and dried so that the thickness after drying was 30 μm, and a pressure-sensitive adhesive sheet for resist removal was produced.

Comparative Example 2 A resist removing adhesive sheet was prepared in the same manner as Comparative Example 1 except that the acrylic adhesive solution b of Example 2 was used in place of the acrylic adhesive solution a. .

Comparative Example 3 A resist-removing pressure-sensitive adhesive sheet was prepared in the same manner as in Comparative Example 1 except that the acrylic pressure-sensitive adhesive solution c of Example 3 was used in place of the acrylic pressure-sensitive adhesive solution a. .

Comparative Example 4 The adhesive sheet of Example 4 was attached to the adhesive surface of the adhesive sheet prepared in Comparative Example 1 to obtain a resist-removing adhesive sheet with a separator.

For each of the resist removing pressure sensitive adhesive sheets of Examples 1 to 4 and Comparative Examples 1 to 4 described above, the amounts of metal elements and their compounds (in terms of metal elements) contained in the substrate and the pressure sensitive adhesive were measured. did. The results are as shown in Table 1 and Table 2. The above-mentioned measurement was performed for titanium and germanium by the following elemental analysis method 1 and for other elements by the following elemental analysis method 2. The resist-removing pressure-sensitive adhesive sheets with separators of Example 4 and Comparative Example 4 were obtained by peeling the separator and then performing the above-mentioned measurement.

<Elemental Analysis Method 1> An adhesive sheet consisting of a base material and an adhesive was heated in a quartz crucible. The ash was decomposed with sulfuric nitric acid, heated to remove sulfuric acid by evaporation, and then diluted nitric acid was added. The lysate was diluted with distilled water and quantified by ICP emission spectrometry. In particular, germanium is an element that easily volatilizes, so the decomposition work was performed under mild conditions, and an addition recovery test was performed to confirm the yield.

<Elemental analysis method 2> An adhesive sheet composed of a base material and an adhesive was placed in a platinum plate at 550.
Heated at ° C. The ash was dissolved with sulfuric nitric acid. It was diluted with diluted hydrochloric acid and quantified by ICP emission spectrometry. In particular, since antimony is an element that easily volatilizes, the decomposition work was carried out under mild conditions, and an addition recovery test was conducted to confirm the yield.

[0055]

[Table 1]

[0056]

[Table 2]

Next, a resist film image removal test was conducted using the resist removing adhesive sheets of Examples 1 to 4 and Comparative Examples 1 to 4 in the following manner. First, each adhesive sheet was attached by pressure bonding on a heating plate at 130 ° C. to the entire surface of a resist film image produced on a silicon wafer by the following method. Next, ultraviolet rays were irradiated with a high-pressure mercury lamp at an irradiation amount of 1 J / cm ² to perform curing treatment. After that, when this adhesive sheet was peeled off, the resist film image was peeled off together with the adhesive sheet in any of the adhesive sheets.

<Production of resist film image> A positive type photoresist comprising cresol novolak resin, naphthoquinone diazide sulfonic acid ester of polyhydroxy compound and ethyl lactate is applied on the surface of a silicon wafer (semiconductor substrate), heated and exposed. Then, development and post-baking were performed to form a resist film image (resist pattern) on the entire surface. Thereafter, P ⁺ ions are added at 1 × 10 ¹² ions / cm ^2.
Was injected over the entire surface at a concentration of.

In the above-mentioned resist film image removal test, the metal element transferred to the surface of the silicon wafer after peeling and removing by the adhesive sheet was analyzed by total reflection X-ray fluorescence analysis, and the W-Lβ1 line and the Mo-Kα1 line were detected. Was analyzed. A silicon wafer contaminated with a known concentration of Ni was used for the quantification.
The results are as shown in Table 3.

In Table 3, "ND" means below the lower limit of detection, and the lower limit of detection of each metal element is as follows. K: 2.0 × 10 ¹⁰ atom / cm ² Ca: 1.6 × 10 ¹⁰ atom / cm ² Ti: 1.0 × 10 ¹⁰ atom / cm ² Mn: 0.40 × 10 ¹⁰ atom / cm ² Fe: 0.32 × 10 ¹⁰ atom / cm ² Ni: 0.20 × 10 ¹⁰ atom / cm ² Cu: 0.18 × 10 ¹⁰ atom / cm ² Zn: 0.15 × 10 ¹⁰ atom / cm ² Ge: 2. 0 × 10 ¹⁰ atom / cm ² Sb: 3.3 × 10 ¹⁰ atom / cm ²

[0061]

[Table 3]

Next, the resist sheets of the adhesive sheets for removing the resists of Examples 1 to 4 and Comparative Examples 1 to 4 were directly attached to the silicon wafer, that is, the impurities ( The transferability of (metal element) was investigated. That is, an adhesive sheet was attached to the mirror surface of a silicon wafer washed with ultrapure water, and ultraviolet rays were applied at 1 J / c with a high pressure mercury lamp.
It was irradiated with a dose of m ² for curing treatment, and then peeled off.
After peeling, the metal element transferred to the mirror surface of the silicon wafer was analyzed in the same manner as described above. The results are shown in Table 4 together with the analysis result (control example 1) of the mirror surface of the silicon wafer immediately after washing with ultrapure water, that is, before sticking the adhesive sheet.

[0063]

[Table 4]

From the results of Tables 1 and 2 above, Comparative Examples 1 to 1
In each adhesive sheet of No. 4, the amount of antimony contained in the base material and the adhesive has a high value of 150 ppm or more, whereas in each of the adhesive sheets of Examples 1 to 4 of the present invention,
The amount of the above-mentioned antimony is very small, and other metal elements (except germanium) other than antimony also show low values.

Further, from the results in Table 3, when the resist film image on the silicon wafer was peeled off using each of the adhesive sheets of Comparative Examples 1 to 4, the transfer amount of antimony transferred to the surface of the silicon wafer was , (7.1-14) × 10 ¹⁰ at
Although the value is as high as om / cm ² , Examples 1 to 1 of the present invention
In each of the pressure-sensitive adhesive sheets of No. 4, the transfer amount is as low as the detection lower limit value of 3.3 × 10 ¹⁰ atoms / cm ² or less.

Further, from the results of Table 4, when the respective adhesive sheets of Comparative Examples 1 to 4 were directly attached on a silicon wafer,
The transfer amount is (6.8 to 9.2) × 10 ¹¹ atom / cm.
^Although it increases more than ² , the adhesive sheets of Examples 1 to 4 of the present invention still have a detection limit of 3.3 ×.
It is suppressed to 10 ¹⁰ atom / cm ² or less, and the transfer amount is greatly reduced even when directly attached to a silicon wafer.

As is clear from these results, in the method of peeling off the resist film image on the silicon wafer using each adhesive sheet of Comparative Examples 1 to 4, the impurity element in the adhesive sheet was used. There is a high possibility that an electrical failure will occur on the wafer due to the transfer of the toner and cause problems such as yield of the wafer and deterioration of reliability.
It is understood that such problems can be reduced when the wafer is used, and it can greatly contribute to the improvement of the yield and reliability of the wafer.

─────────────────────────────────────────────────── ─── Continued Front Page (72) Masayuki Yamamoto 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (72) Koichi Hashimoto 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture No. Nitto Denko Corporation (72) Inventor Chiaki Harada 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (56) Reference JP-A-6-267893 (JP, A) JP HEI 6-151298 (JP, A) JP HEI 4-345015 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027 C09J 7/02

Claims (2)

(57) [Claims] 1. An adhesive sheet for peeling and removing an image of a resist film existing on an article, wherein an adhesive is provided on a substrate, and a separator is attached to the adhesive surface if necessary. , The amount of electrically active metal elements other than Group 14 elements in the periodic table contained in the pressure-sensitive adhesive and its base material in the state where the separator is peeled off at the time of use, and the amount of their compounds are converted to individual elements The adhesive sheet for resist removal is characterized in that it is 20 ppm or less. 2. A resist removing method comprising: sticking the adhesive sheet according to claim 1 on an article having a resist film image, and peeling and removing the adhesive sheet and the resist film image integrally. Periodic rule 1 transferred from sheets to articles
The electrically active metal element other than the Group 4 element and its compound have an atomic number density of each element of 5 × 10 ¹⁰ atom /
A method of removing resist, wherein the method is cm ² or less.