JP5485525B2 - Double sided tape for fixing abrasive cloth - Google Patents

Description

The present invention relates to a double-sided tape for fixing a polishing cloth having an adhesive layer for fixing a platen that is excellent in resistance to acids and alkalis and can be peeled off from the platen without any adhesive residue after use.

For example, in the step of polishing a semiconductor wafer to a predetermined thickness, polishing is performed using a polishing cloth fixed to a surface plate of a polishing machine. In order to fix the polishing cloth to the surface plate of the polishing machine, a double-sided tape is usually used. Such a double-sided tape for fixing a polishing cloth is required to have a sufficient adhesive strength so that the polishing cloth does not peel during polishing, and can be peeled off from the surface plate without any adhesive residue after use.

Patent Document 1 describes a double-sided tape for fixing a polishing pad in which an adhesive layer made of a nitrile rubber adhesive is provided on one surface of a plastic film and a removable adhesive layer is provided on the other surface. ing. And it describes that the adhesive layer side which consists of a nitrile rubber-type adhesive layer is adhere | attached on polishing cloth, and the releasable adhesive layer side is adhere | attached on a surface plate and used. In the Example of patent document 1, the polymer which copolymerized acrylic acid, butyl acrylate, and vinyl acetate is used as an adhesive which comprises a releasable adhesive layer. The double-sided adhesive tapes obtained in the examples can maintain high adhesive strength even after being immersed in a 20% solution of fine cerium oxide powder at 50 ° C. for 5 days, compared to the case where both sides are made of an acrylic adhesive. Have been described.

Patent Document 2 discloses a layer in which a pressure-sensitive adhesive layer mainly composed of an acrylic polymer is laminated on one surface of a plastic film support, and a thermally active adhesive layer made of polyester or polyurethane is laminated on the adhesive layer. And a double-sided adhesive tape for fixing an abrasive, which is provided with a removable pressure-sensitive adhesive layer on the other surface. And it describes that a heat-activatable adhesive layer is used by adhering it to an abrasive. In the example of Patent Document 2, the double-sided tape provided with the thermally active adhesive layer is immersed for 5 days in a 50 ° C. aqueous solution adjusted to pH 10 with potassium hydroxide, compared to the case where the acrylic adhesive layer is used on both sides. In this case, it is described that high adhesive strength can be maintained.

However, in recent years, when a strongly acidic slurry solution or a strongly alkaline slurry solution is used when polishing a semiconductor wafer or the like, the double-sided adhesive tape described in Patent Documents 1 and 2 uses an adhesive on the surface plate side. There was a problem that the agent layer easily deteriorates due to the influence of acid or alkali and may be peeled off during polishing. If the pressure-sensitive adhesive layer on the polishing cloth fixing side described in Patent Documents 1 and 2 is also used on the surface plate side, the resistance to acid and alkali is excellent. However, when such an adhesive layer is used, it cannot be peeled off from the surface plate after use. There has been a demand for a double-sided adhesive tape for fixing a polishing cloth having a pressure-sensitive adhesive layer for fixing a platen that is excellent in resistance to acids and alkalis and can be peeled off from the platen after use without any adhesive residue.
JP-A-6-145611 JP-A-6-172721

An object of the present invention is to provide a double-sided tape for fixing a polishing cloth having a pressure-sensitive adhesive layer for fixing a platen that can be peeled off from the platen without any adhesive residue after use.

The present invention provides a polishing cloth fixing double-sided tape for fixing a polishing cloth to a surface plate of a polishing machine in a polishing step using an acidic solution, and a base film and one surface of the base film It is composed of the formed abrasive cloth fixing pressure-sensitive adhesive layer and the pressure-sensitive acrylic pressure-sensitive adhesive layer formed on the other surface of the base film, and (A) a size of 10 mm × 10 mm Using the double-sided tape for fixing the abrasive cloth cut to a thickness, a glass plate of 100 mm × 50 mm × 1.8 mm and an acrylic plate of 50 mm × 15 mm × 2 mm are placed on the short side of the glass plate. The center of the double-sided adhesive tape for polishing cloth fixing is 20 mm from the end and 20 mm from the end of the long side, and the center of the surface plate fixing adhesive layer side is 7.5 mm from the end of the short side of the acrylic plate. Polishing at a position of 7.5 mm from the end Bonding the double-sided tape for fixing cloth to the center of the adhesive layer for fixing the polishing cloth, and (B) a weight of 200 g at a position 30 mm from the center of the double-sided tape for fixing the polishing cloth of the acrylic plate. (C) a step of immersing in a hydrogen chloride aqueous solution at 23 ° C. and pH 1 with the weight suspended, and (D) the acrylic plate is polished from the glass plate from the start of the immersion. In a torsional shear test comprising a step of measuring the peeling time required for peeling together with the cloth fixing double-sided tape, the double-sided tape for polishing cloth fixing having a measured peeling time of 2 minutes 30 seconds or more.
The present invention is described in detail below.

The inventors of the present invention have found that peeling during polishing is difficult to improve even if an adhesive is designed by paying attention only to the adhesive strength against a flat plate and the peel resistance. And if it was the adhesive tape which has the tolerance with respect to rotation of the polishing cloth in a chemical | medical solution, it discovered that peeling did not occur easily. And it discovered that strong resistance with respect to rotation of the polishing cloth in a chemical | medical solution was able to be exhibited only when the peeling time measured in a specific torsional shear test is more than a certain value, and completed the present invention.

The double-sided tape for fixing an abrasive cloth of the present invention (hereinafter also simply referred to as “double-sided tape”) has a measured peeling time of 2 minutes 30 seconds or more in a torsional shear test. When the peeling time is less than 2 minutes and 30 seconds, peeling occurs when polishing is performed in acid or alkali. A preferable lower limit of the peeling time is 5 minutes, and a more preferable lower limit is 10 minutes.

If the double-sided tape does not peel even if the acrylic plate rotates 60 degrees or more from the horizontal state due to the creep phenomenon, or if only the acrylic plate peels off with only a part of the double-sided tape without the double-sided tape, Regardless of the length of time until peeling, it is not included in the present invention.

The torsional shear test will be described.
The torsional shear test is performed by the following steps (A) to (D).
(A) Using a double-sided tape cut to a size of 10 mm × 10 mm, a glass plate of 100 mm × 50 mm × 1.8 mm and an acrylic plate of 50 mm × 15 mm × 2 mm The center of the double-sided tape on the side of the adhesive plate for fixing the surface plate comes to a position 20 mm from the end of the side and 20 mm from the end of the long side, and 7.5 mm from the end of the short side of the acrylic plate and 7. A process of bonding so that the center of the double-sided tape on the side of the pressure-sensitive adhesive layer for fixing the polishing cloth is located at a position of 5 mm.

(B) A step of hanging a 200 g weight at a position 30 mm from the center of the double-sided tape on the acrylic plate.
(C) A step of dipping in a hydrogen chloride aqueous solution at 23 ° C. and pH 1 with the weight suspended. (FIG. 1 shows a schematic diagram showing a state in which the weight is suspended in an aqueous hydrogen chloride solution in a state where the weight is suspended in step (C).)
(D) The process of measuring the peeling time taken from the start of immersion until an acrylic board peels with a double-sided tape from a glass plate.

The double-sided tape of the present invention includes a base film, an adhesive layer for fixing a polishing cloth formed on one surface of the base film, and an adhesive for fixing a platen formed on the other surface of the base film. It consists of an agent layer.

It does not specifically limit as said base film, For example, the foamed sheet etc. which consist of synthetic resin films, such as a polyester-type resin, a polypropylene resin, polyolefin-type resins, such as a polyurethane-type resin and a polypropylene resin, etc. are mentioned. Among them, a synthetic resin film made of a polyester resin is preferable because it is flat, has little thickness fluctuation, and has a certain strength.

Although it does not specifically limit as thickness of the said base film, When it is a non-foamed body, a preferable minimum is 15 micrometers and a preferable upper limit is 70 micrometers. When the thickness of the base film is less than 15 μm, the base film may be broken when the double-sided tape is peeled off from the surface plate of the polishing machine, and may not be peeled cleanly. Adjustment of the pressure applied when the cloth and the double-sided tape are laminated and integrated becomes difficult, and the adhesive strength between the polishing cloth and the pressure-sensitive adhesive layer for the polishing cloth may be lowered. The minimum with more preferable thickness of the said base film is 20 micrometers, and a more preferable upper limit is 50 micrometers.

The pressure-sensitive adhesive layer for fixing the platen is made of a pressure-sensitive acrylic pressure-sensitive adhesive. By using the pressure-sensitive acrylic pressure-sensitive adhesive, the double-sided tape of the present invention can be easily peeled off from the surface plate after use.
Although it does not specifically limit as said pressure-sensitive acrylic adhesive, The thing which has a (meth) acrylic-acid alkylester copolymer as a main component is suitable.
In this specification, (meth) acrylic acid means acrylic acid or methacrylic acid.

Although it does not specifically limit as said (meth) acrylic-acid alkylester copolymer, It forms by copolymerizing the monomer mixture containing acrylic acid and the (meth) acrylic-acid alkylester monomer whose carbon number of an alkyl group is 1-12. Those are preferred.

Examples of (meth) acrylic acid alkyl ester monomers having 1 to 12 carbon atoms in the alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic. Examples include isopropyl acid, (n-butyl) (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, and the like. These (meth) acrylic acid alkyl ester monomers may be used alone or in combination of two or more. Especially, since it is cheap and is excellent in the adhesive characteristic, it is preferable to contain (meth) acrylic acid-n-butyl.

When the said monomer mixture contains (meth) acrylic acid-n-butyl, the minimum with the preferable content is 90 weight%, and a preferable upper limit is 94 weight%. When the content of (meth) acrylic acid-n-butyl is less than 90% by weight, the adhesive strength in the high temperature range of the obtained pressure-sensitive adhesive layer for fixing the platen is inferior and may be peeled off by overheating during polishing. If it exceeds 94% by weight, the 180 ° peeling force may be reduced, and may be peeled off during polishing.

The monomer mixture may contain other vinyl monomers as necessary. The other vinyl monomer is not particularly limited. For example, cyclohexyl (meth) acrylate, 2-methylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, isobornyl (Meth) acrylic acid cyclic alkyl esters such as (meth) acrylate, (meth) acrylic acid aryl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. Hydroxyalkyl esters, dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate, diethyl itaconate, glycidyl (meth) acrylate, allyl glycidyl ether, styrene, α Methyl styrene, m- methyl styrene, p- methyl styrene, vinyl toluene, p- methoxystyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, vinyl acetate, etc. may be used. These may be used independently and may use 2 or more types together.

The minimum with a preferable weight average molecular weight of the said (meth) acrylic-acid alkylester type copolymer is 200,000, and a preferable upper limit is 400,000. If the weight average molecular weight is less than 200,000, the cohesive force is reduced, and cohesive failure may occur due to re-peeling, and adhesive residue may be generated. May end up.
In addition, the weight average molecular weight of the said (meth) acrylic-acid alkylester type copolymer means the value measured as a polystyrene conversion molecular weight by the gel permeation chromatography (GPC) method. Specifically, for example, the diluted solution obtained by diluting the (meth) acrylic acid alkyl ester copolymer 100 times with tetrahydrofuran (THF) is filtered through a filter, and the obtained filtrate is filtered through a column (for example, , Using a product name “2690 Separations Model” manufactured by Water, Inc.).

The method for preparing the (meth) acrylic acid alkyl ester copolymer is not particularly limited, and examples thereof include a method of radical polymerization of the monomer mixture in the presence of a polymerization initiator. The radical polymerization method is not particularly limited, and conventionally known polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization can be used.

The polymerization initiator is not particularly limited. For example, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t -Butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate and the like. These polymerization initiators may be used independently and 2 or more types may be used together. Of these, t-hexyl peroxypivalate is preferred.

The minimum with preferable content of the said (meth) acrylic-acid alkylester type copolymer in the said pressure-sensitive acrylic adhesive is 50 weight%. If the content of the (meth) acrylic acid alkyl ester copolymer is less than 50% by weight, the adhesive strength is lowered, and peeling may occur during polishing. The upper limit of the content of the (meth) acrylic acid alkyl ester copolymer is not particularly limited, and the entire amount may be the (meth) acrylic acid alkyl ester copolymer.

The platen fixing pressure-sensitive adhesive layer may further contain a tackifying resin. The tackifying resin is not particularly limited, and examples thereof include a xylene resin, a phenol resin, a rosin resin, and a terpene resin. These tackifier resins may be used alone or in combination of two or more.

In the case where the pressure-sensitive adhesive layer for fixing the platen contains the tackifying resin, a preferable upper limit of the blending amount with respect to 100 parts by weight of the pressure-sensitive acrylic pressure-sensitive adhesive is 100 parts by weight. When the content of the tackifying resin exceeds 100 parts by weight, the obtained pressure-sensitive adhesive layer for fixing the platen becomes hard, and the adhesive strength and tack may be reduced.

The pressure-sensitive adhesive layer for fixing the platen further preferably contains a crosslinking agent. By containing a crosslinking agent, a crosslinked structure can be formed between the main chains of the resin constituting the pressure-sensitive adhesive layer. By appropriately adjusting the type and amount of the crosslinking agent, it becomes easy to adjust the gel fraction of the pressure-sensitive adhesive layer for fixing the platen to a desired range described later.

It does not specifically limit as said crosslinking agent, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy-type crosslinking agent, a metal chelate type crosslinking agent etc. are mentioned. Among these, an isocyanate-based crosslinking agent is preferable because it easily exhibits performance such as heat resistance and durability.

In the case where the pressure-sensitive adhesive layer for fixing the platen contains the crosslinking agent, the preferred lower limit of the blending amount with respect to 100 parts by weight of the pressure-sensitive acrylic pressure-sensitive adhesive is 0.5 parts by weight, and the preferred upper limit is 2 parts by weight. If the content of the crosslinking agent is less than 0.5 parts by weight, the cohesive force of the obtained pressure-sensitive adhesive layer for fixing the platen is inferior, and may cause cohesive failure during re-peeling. In some cases, the adhesive strength and tack of the obtained pressure-fixing pressure-sensitive adhesive layer may be reduced. The minimum with more preferable content of the said crosslinking agent is 0.7 weight part, and a more preferable upper limit is 1.5 weight part.

The said surface plate fixing adhesive layer may contain conventionally well-known additives, such as a coloring agent, a filler, and anti-aging agent, as needed.

The above-mentioned pressure-sensitive adhesive layer for fixing the platen has a preferable lower limit of the gel fraction of 30% and a preferable upper limit of 70%. When the gel fraction is less than 30%, the cohesive force of the pressure-sensitive adhesive layer for fixing the platen is inferior and may be coherently broken during re-peeling. When it exceeds 70%, the adhesive force and tack are reduced. Sometimes. The more preferable lower limit of the gel fraction of the pressure-sensitive adhesive layer for fixing the platen is 50%.

The gel fraction can be measured by the following method.
The pressure-sensitive adhesive tape of the present invention is cut into a flat rectangular shape of 50 mm × 25 mm, and the pressure-sensitive adhesive layer for fixing the surface plate is scraped off from the double-sided tape to prepare a test piece. After immersing the obtained test piece in ethyl acetate at 23 ° C. for 24 hours, the test piece is taken out from ethyl acetate through a 200-mesh stainless steel mesh and dried at 110 ° C. for 1 hour. And the weight of the test piece after drying is measured, and a gel fraction is computed using a following formula. Note that a release film as described below is not laminated on the double-sided tape.
Gel fraction (% by weight) = 100 × W ₂ / W ₁
(W ₁ represents the weight of the test piece before dipping, and W ₂ represents the weight of the test piece after dipping and drying.)

Although it does not specifically limit as thickness of the said surface plate fixing adhesive layer, A preferable minimum is 20 micrometers and a preferable upper limit is 60 micrometers. When the thickness of the pressure-sensitive adhesive layer for fixing the platen is less than 20 μm, the adhesive force is inferior and may be easily peeled off. Further, in general, it has been considered that the thicker pressure-sensitive adhesive layer has better adhesive force and is difficult to peel off. However, when the thickness of the pressure-sensitive adhesive layer for fixing the platen exceeds 60 μm, The deviation due to the creep phenomenon of the layer becomes large, the resistance to torsional moment becomes low, and the peeling time in the above-described torsional shear test may not be achieved. A more preferable upper limit of the thickness of the pressure-sensitive adhesive layer for fixing the platen is 40 μm.

The pressure-sensitive adhesive layer for fixing the surface plate is obtained by cutting the double-sided tape of the present invention to 100 mm × 25 mm, sticking the pressure-sensitive adhesive layer for fixing the surface plate to a glass plate, and immersing it in a pH 1 hydrogen chloride aqueous solution at 23 ° C. for 24 hours. The preferable lower limit of 180 ° adhesive strength to glass measured in accordance with JIS Z0237 later is 10 N / 25 mm, and the preferable upper limit is 18 N / 25 mm. If the 180 ° adhesive strength to the glass after acid treatment is less than 10 N / 25 mm, it may peel off from the surface plate during polishing, and if it exceeds 18 N / 25 mm, it will be difficult to peel off after use. There is.

The pressure-sensitive adhesive layer for fixing the surface plate is obtained by cutting the double-sided tape of the present invention to 100 mm × 25 mm, sticking the pressure-sensitive adhesive layer for fixing the surface plate to a glass plate, and subjecting it to a constant load test in accordance with JIS Z0237, pH 1 In the case of using a 50 g weight at 23 ° C. in an aqueous hydrogen solution, it is preferable that the time required for 4 cm travel is 5 minutes or more. The double-sided tape may be measured by peeling 20 mm from the end and dropping a 50 g load on the end.

It does not specifically limit as an adhesive which comprises the said abrasive cloth fixing adhesive layer, It may be the same as the said surface plate fixing adhesive layer, and may differ. Since the adhesive layer for fixing the polishing cloth does not require the peelability after use unlike the pressure-sensitive adhesive layer for fixing the surface plate, various pressure-sensitive adhesives having a strong adhesive force can be selected and used. . Moreover, it is not restricted to a pressure sensitive type, A heat sensitive type, such as a hot-melt type, can also be used.
Specific examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer for fixing the polishing cloth include rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives. Especially, since it can adhere | attach firmly, a rubber-type adhesive or an acrylic adhesive is suitable.

As an acrylic adhesive used for the said adhesive layer for polishing cloth fixation, what contains the copolymer containing butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and tackifying resin is preferable.

The blending amount of the butyl (meth) acrylate in the copolymer is such that the preferred lower limit in the total 100 parts by weight of all copolymer components is 10 parts by weight, and the preferred upper limit is 50 parts by weight. When the blending amount of the butyl (meth) acrylate is less than 10 parts by weight, the resulting pressure-sensitive adhesive layer for fixing a polishing cloth may be inferior in heat resistance. The cloth fixing pressure-sensitive adhesive layer may become hard and cannot follow the waviness of the polishing cloth.

The blending amount of the 2-ethylhexyl (meth) acrylate in the copolymer is preferably 50 parts by weight, and preferably 80 parts by weight, with respect to a total of 100 parts by weight of all copolymer components. When the blending amount of 2-ethylhexyl (meth) acrylate is less than 50 parts by weight, the resulting adhesive layer for fixing the polishing cloth becomes hard and may not be able to follow the waviness of the polishing cloth. If it exceeds 1, the resulting abrasive cloth fixing pressure-sensitive adhesive layer may be inferior in heat resistance.

The tackifying resin is not particularly limited, and examples thereof include a xylene resin, a phenol resin, a rosin resin, and a terpene resin. These tackifier resins may be used alone or in combination of two or more. Of these, a xylene resin is preferable, and an alkylphenol reaction product of the xylene resin is more preferable.
As a commercial item of the alkylphenol reaction material of the said xylene resin, "Nikanol T series" etc. by a Fudou company are mentioned, for example.

The thickness of the pressure-sensitive adhesive layer for fixing the polishing cloth is not particularly limited, but a preferable lower limit is 30 μm and a preferable upper limit is 100 μm. When the thickness of the pressure-sensitive adhesive layer for fixing the polishing cloth is less than 30 μm, the adhesive force becomes insufficient, and the polishing cloth may be peeled off during polishing. When the thickness exceeds 100 μm, the cohesive force decreases. Sometimes. The more preferable lower limit of the thickness of the abrasive cloth fixing pressure-sensitive adhesive layer is 40 μm, the more preferable upper limit is 80 μm, the still more preferable lower limit is 50 μm, and the still more preferable upper limit is 70 μm.

The preferable lower limit of the 180 ° peel force with respect to the stainless steel plate measured in accordance with JIS Z0237 is 10 N / 25 mm for the above-mentioned adhesive layer for polishing cloth fixing. If the 180 ° peel force is less than 10 N / 25 mm, the polishing cloth may peel off during polishing. The more preferable lower limit of the 180 ° peel force is 15 N / 25 mm.

Examples of the method for producing the double-sided tape of the present invention include the following methods.
First, prepare a pressure-sensitive adhesive solution by adding a solvent to one pressure-sensitive adhesive, apply this pressure-sensitive adhesive solution to the surface of the substrate, and completely remove the solvent in the pressure-sensitive adhesive solution to form a pressure-sensitive adhesive layer. To do. Next, a release film is overlaid on the formed pressure-sensitive adhesive layer so that the release treatment surface faces the pressure-sensitive adhesive layer.
Next, a release film different from the release film is prepared, the other adhesive solution is applied to the release treatment surface of the release film, and the solvent in the adhesive solution is completely removed by drying. Thus, a laminated film in which an adhesive layer is formed on the surface of the release film is produced.
The obtained laminated film is laminated on the back surface of the base material on which the pressure-sensitive adhesive layer is formed in a state where the pressure-sensitive adhesive layer faces the back surface of the base material to produce a laminate.
Then, by pressing the laminate with a rubber roller or the like, a double-sided tape in which the pressure-sensitive adhesive layer is laminated and integrated on both surfaces of the base material, and the release film is laminated on the surface of the pressure-sensitive adhesive layer in a peelable manner. Can be obtained.

In addition, two sets of laminated films are produced in the same manner, and a laminated body is produced by superposing these laminated films on both sides of the base material with the adhesive layer of the laminated film facing the base material. By pressing this laminate with a rubber roller, etc., a double-sided tape is produced in which the adhesive layer is laminated and integrated on both sides of the substrate, and the release film is laminated on the surface of the adhesive layer in a peelable manner. May be.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the tolerance with respect to an acid and an alkali, and can provide the double-sided tape for polishing cloth fixing which has an adhesive layer for surface plate fixing which can peel from a surface plate without adhesive residue after use.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
In a reactor equipped with a thermometer, a stirrer and a condenser, 8 parts by weight of acrylic acid, 91.7 parts by weight of acrylic acid-n-butyl, 0.3 part by weight of 2-hydroxyethyl acrylate, and 80 parts of ethyl acetate After adding parts by weight, the reactor was heated to initiate reflux. Subsequently, 0.1 part by weight of t-hexyl peroxypivalate was added as a polymerization initiator in the reactor. The solution was refluxed at 70 ° C. for 5 hours to obtain a solution of a (meth) acrylic acid alkyl ester copolymer having a solid content of 43%.
When the weight average molecular weight of the obtained (meth) acrylic acid alkyl ester copolymer was measured by a GPC method using “2690 Separations Model” manufactured by Water as a column, it was 2270,000.

In the obtained (meth) acrylic acid alkyl ester copolymer solution, 125 parts by weight of ethyl acetate (Fuji Chemical Co., Ltd.) and isocyanate-based cross-linking agent (Sekisui Fuller “Cure” with respect to 100 parts by weight of the solid content. Agent UA ") 1.0 part by weight was added and stirred to obtain a pressure-sensitive acrylic pressure-sensitive adhesive solution.

The obtained pressure-sensitive acrylic pressure-sensitive adhesive solution was applied to the surface of a polyethylene terephthalate (PET) film having a thickness of 23 μm and dried at 100 ° C. for 5 minutes to form a pressure-sensitive adhesive layer for fixing a platen having a thickness of 30 μm. . On the formed pressure-sensitive adhesive layer for fixing the platen, a 50 μm-thick PET film having been subjected to the release treatment was superposed so that the release treatment surface was opposed to the pressure-sensitive adhesive layer for fixing the platen.
On the other hand, a 50 μm-thick PET film having been subjected to another release treatment is prepared, and the pressure-sensitive acrylic pressure-sensitive adhesive solution obtained is applied to the release-treated surface of this PET film and dried at 100 ° C. for 5 minutes. Thus, a pressure-sensitive adhesive layer for fixing a polishing cloth having a thickness of 50 μm was formed.

Laminate the PET film on which the adhesive layer for fixing the polishing cloth is formed, with the adhesive layer for fixing the polishing cloth facing the back surface of the PET film on which the adhesive layer for fixing the surface plate is opposed. Produced. A 2 kg rubber roller was reciprocated once at a speed of 300 mm / min on this laminate, and then cured at 23 ° C. for 7 days, whereby a pressure-sensitive adhesive layer for fixing a platen and a pressure-sensitive adhesive for fixing a polishing cloth on both surfaces of the substrate. A double-sided tape in which the layers were laminated and integrated was obtained.

(Example 2)
A double-sided tape was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer for fixing the platen was 60 μm.

(Comparative Example 1)
A double-sided tape was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer for fixing the platen was 80 μm.

(Comparative Example 2)
Add 3 parts by weight of acrylic acid, 38 parts by weight of acrylic acid-n-butyl, 59 parts by weight of acrylic acid-2-ethylhexyl acrylate, and 80 parts by weight of ethyl acetate to a reactor equipped with a thermometer, stirrer and condenser. After that, the reactor was heated to start refluxing. Subsequently, 0.1 part by weight of t-hexyl peroxypivalate was added as a polymerization initiator in the reactor. The solution was refluxed at 70 ° C. for 5 hours to obtain a solution of a (meth) acrylic acid alkyl ester copolymer.
When the weight average molecular weight of the obtained (meth) acrylic acid alkyl ester copolymer was measured by a GPC method using “2690 Separations Model” manufactured by Water as a column, it was 213,000.
A double-sided tape was obtained in the same manner as in Example 2 except that the obtained (meth) acrylic acid alkyl ester copolymer was used.

(Evaluation)
The double-sided tapes obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated as follows.
The results are shown in Table 1.

(1) Dispersion measurement The obtained (meth) acrylic acid alkyl ester copolymer was diluted 100-fold with tetrahydrofuran (THF), and the resulting diluted solution was filtered with a filter. The weight average molecular weight (Mw) and the number average molecular weight (Mn) were obtained by GPC method using a trade name “2690 Separations Model” of Water. The dispersity was determined by dividing the obtained weight average molecular weight (Mw) by the number average molecular weight (Mn).

(2) Measurement of gel fraction The obtained double-sided tape was cut into a flat rectangular shape of 50 mm x 25 mm to produce a test piece, and the weight W ₁ was measured. After immersing the test piece in ethyl acetate at 23 ° C. for 24 hours, the test piece was taken out from ethyl acetate through a 200-mesh stainless steel mesh and dried at 110 ° C. for 1 hour. The weight W ₂ after drying the test piece was measured. The gel fraction was calculated by the following formula using the weight W ₀ of the PET film used as the substrate.
Gel fraction (% by weight) = 100 × (W ₂ −W ₀ ) / (W ₁ −W ₀ )

(3) Measurement of 180 ° peeling adhesive strength A PET film having a thickness of 38 μm was lined on an adhesive layer for polishing cloth of a double-sided tape, and then a test piece having a plane rectangular shape of 100 mm length × 25 mm width was cut out. The adhesive layer for abrasive cloth of this test piece was put on the stainless steel plate and pressed with a 2 kg roller, and the test piece was stuck on the stainless steel plate. After being left for 30 minutes in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%, 180 ° peel adhesion (vs. SUS) was measured using a tensile tester in accordance with JIS Z0237.
Moreover, 180 degree peeling adhesive force (vs. glass) was measured by the same method.

(4) Measurement of holding power A 38 μm-thick PET film was lined on the acrylic adhesive layer of the double-sided tape, a 20 mm square flat test piece was cut out, and the adhesive layer was stuck on a stainless steel plate. Thereafter, it was cured at 40 ° C. for 60 minutes.
After placing the test piece horizontally on the lower surface of the PET film, applying a load of 1 kgf to the end of the test piece in the vertical direction, and applying the load to the test piece The peel length after 1 hour at 40 ° C. was measured using a magnifying glass.
Further, in the same test, after applying a load to the test piece, the peel length after 1 hour at 60 ° C. was measured using a loupe.

(5) Evaluation of adhesive residue In the measurement of 180 ° peeling adhesive force described in the above (3), it was visually observed whether or not glue was attached to the stainless steel plate after peeling.

(6) Measurement of 180 ° peel adhesion after acid immersion test A 38 μm thick PET film was lined on the adhesive layer for polishing cloth of the double-sided tape, and then a 100 mm long x 25 mm wide rectangular test piece was cut out. It was.
The pressure-sensitive adhesive layer for fixing the platen of this test piece was placed on a glass plate and pressed with a 2 kg roller, and the test piece was stuck on the glass plate. In this state, it was immersed in a 0.1 mol / l hydrogen chloride aqueous solution for 24 hours in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. After immersion, the sample was taken out and 180 ° peel adhesion (to glass) was measured using a tensile tester in accordance with JIS Z0237.

(7) Constant load peel test in chemical solution A 38 μm thick PET film was lined on the adhesive layer for polishing cloth of the double-sided tape, and then a plane rectangular test piece of 100 mm length × 25 mm width was cut out.
The pressure-sensitive adhesive layer for fixing the platen of this test piece was placed on a glass plate and pressed with a 2 kg roller, and the test piece was stuck on the glass plate.
20 mm was peeled from the end of the test piece, and a 50 g weight was attached. The sample was immersed in a hydrogen chloride aqueous solution at 23 ° C. and pH 1 with the weight attached, and the speed was calculated by measuring the time required to proceed 4 cm.

(8) Torsional shear test A double-sided tape is cut into a size of 10 mm x 10 mm, and a glass plate of a size of 100 mm x 50 mm x 1.8 mm and an acrylic plate of a size of 50 mm x 15 mm x 2 mm are used. The center of the double-sided tape on the side of the adhesive plate for fixing the platen is 20 mm from the end of the short side and 20 mm from the end of the long side, 7.5 mm from the end of the short side of the acrylic plate and 7 from the end of the long side Bonding was performed so that the center of the double-sided tape on the side of the pressure-sensitive adhesive layer for fixing the abrasive cloth was placed at a position of 5 mm. Next, a 200 g weight was hung at a position 30 mm from the center of the double-sided tape on the acrylic plate. It was immersed in a hydrogen chloride aqueous solution at 23 ° C. and pH 1 with the weight suspended. The peeling time required from the start of immersion until the acrylic plate peeled off from the glass plate together with the double-sided tape was measured.

(9) Evaluation of presence or absence of peeling during polishing The double-sided tape obtained was laminated with an abrasive cloth on the adhesive layer for fixing the abrasive cloth, and bonded using a rubber roll. This was fixed to the surface plate of the polishing apparatus by pressing a rubber roll from the polishing cloth side.
A glass plate was used as a specimen to be polished, W2000 (pH 2.3) manufactured by Cabot Microelectronics was used as a polishing slurry, and the polishing pad was operated at a polishing pressure of 49.0 kPa and a rotation speed of 100 rpm for 5 minutes. Then, the peeling state was visually observed about the interface of a double-sided tape and a surface plate. As a result of performing the above operation 10 times, “◯” indicates that no peeling occurred once out of 10 times, and “△” indicates that swelling did not occur even once in 10 times. The case where peeling was seen once or more in 10 times was evaluated as “x”.

From Table 1, in Comparative Example 1 in which the thickness of the pressure-sensitive adhesive layer for fixing the platen is 80 μm, the torsional shear force is greatly reduced, resulting in peeling during polishing. Further, from Comparative Example 2, even when the molecular weight and the gel fraction are almost the same, in the case where 90 to 94 parts by weight of (meth) acrylate-n-butyl is not contained, the torsional shear force is greatly reduced, resulting in polishing. Time peeling occurred.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the tolerance with respect to an acid and an alkali, and can provide the double-sided tape for polishing cloth fixing which has an adhesive layer for surface plate fixing which can peel from a surface plate without adhesive residue after use.

It is a schematic diagram which shows a mode that it immersed in the hydrogen chloride aqueous solution in the state which suspended the weight in the process (C) of a torsional shear test.

Explanation of symbols

1 Glass plate 2 Double-sided tape 3 Acrylic plate 4 Weight 5 Hydrogen chloride aqueous solution

Claims (1)

A polishing cloth fixing double-sided tape for fixing a polishing cloth to a surface plate of a polishing machine in a polishing step using an acidic solution,
An adhesive for fixing a platen comprising a base film, an adhesive layer for fixing a polishing cloth formed on one surface of the base film, and a pressure sensitive acrylic adhesive formed on the other surface of the base film Consisting of the agent layer,
The pressure-sensitive acrylic pressure-sensitive adhesive constituting the platen-fixing pressure-sensitive adhesive layer is obtained by copolymerizing a monomer mixture containing acrylic acid and (meth) acrylic acid-n-butyl 90 to 94% by weight. It contains 10,000 to 400,000 (meth) acrylic acid alkyl ester copolymers, and the pressure-sensitive adhesive layer for fixing the platen has a gel fraction of 30 to 70% and a thickness of 20 to 60 μm. ,
(A) A glass plate having a size of 100 mm × 50 mm × 1.8 mm and an acrylic plate having a size of 50 mm × 15 mm × 2 mm, using the double-sided tape for fixing abrasive cloth cut to a size of 10 mm × 10 mm. The center of the double-sided tape for polishing cloth fixing on the side of the adhesive plate for fixing the surface plate comes to a position 20 mm from the end of the short side of the glass plate and 20 mm from the end of the long side, and the end of the short side of the acrylic plate From 7.5 mm and 7.5 mm from the end of the long side, the step of pasting together so that the center of the abrasive cloth fixing adhesive layer side of the abrasive cloth fixing double-sided tape comes,
(B) a step of hanging a weight of 200 g at a position 30 mm from the center of the double-sided tape for fixing the polishing cloth of the acrylic plate;
(C) a step of immersing in a hydrogen chloride aqueous solution at 23 ° C. and pH 1 with the weight hanging;
(D) In the torsional shear test including the step of measuring the peeling time taken from the start of the immersion until the acrylic plate peels together with the double-sided tape for fixing the polishing cloth from the glass plate, the peeling time measured A double-sided tape for fixing an abrasive cloth, characterized by being 2 minutes 30 seconds or longer.

Images