WO2014199992A1 - Adhesive sheet and method for producing electronic component using adhesive sheet - Google Patents

Abstract

Provided is an adhesive sheet such that there is no decrease over time in pickup properties of a chip during a pickup step, and that can be used in production lines both having and not having heating before dicing. The adhesive sheet has an adhesive layer comprising an adhesive composition on a substrate film containing polyvinyl chloride and a polyester plasticizer, wherein the adhesive composition contains 100 parts by mass of a (meth)acrylic ester copolymer and 0.01-5 parts by mass of an isocyanate curing agent, and the (meth)acrylic ester compolymer has a weight average molecular weight of 400,000-1,000,000 and contains 40-90 mass% of a butyl(meth)acrylate unit, 5-55 mass% of a methyl(meth)acrylate unit, and 0.1-10 mass% of a monomer unit having a hydroxyl group.

Description

Adhesive sheet and method for producing electronic component using adhesive sheet

The present invention relates to an adhesive sheet and a method for manufacturing an electronic component using the adhesive sheet.

For semiconductor wafers, the adhesive sheet is usually bonded after the circuit is formed, and then cut into element pieces (dicing), washed, dried, stretched (expanded) the adhesive sheet, and peeled off the element pieces from the adhesive sheet. (Pickup), mounting and other processes. As a dicing and / or conveying pressure-sensitive adhesive sheet used in these steps, Patent Document 1 describes an example in which polyvinyl chloride is used as a base material.

Patent Document 2 discloses a composition using a (meth) acrylic acid ester copolymer as the pressure-sensitive adhesive composition.

JP 2006-049509 A JP 2007-246633 A

In the conventional pressure-sensitive adhesive sheet based on polyvinyl chloride, the plasticizer migrates from the base material to the pressure-sensitive adhesive layer over time, which causes a problem in chip pickup performance in the pickup process.
In addition, when the adhesive sheet is used for dicing the adherend of the wafer or package substrate, the adhesive sheet is heated to about 75 ° C. after being attached to the adherend, and then dicing is performed. Dicing may be performed. Heating is performed in order to increase adhesion between the adherend and the pressure-sensitive adhesive sheet and prevent chip jumping when the adherence between the adherend and the pressure-sensitive adhesive sheet is not good. When heating is performed, dicing is performed. The pick-up property of later chips may deteriorate. Further, when the composition of the pressure-sensitive adhesive is adjusted so that the pick-up property of the chip after dicing is not deteriorated even if the heating is performed, the adhesiveness when the heating is not performed may be deteriorated. Because of these circumstances, it has been difficult to use the same adhesive sheet in a production line without heating and a production line with heating, and separate adhesive sheets designed with and without heating. There was no choice but to use.

The present invention has been made in view of such circumstances, and does not cause deterioration of the pick-up property of the chip in the pick-up process with time, and can be used in both a heating line with and without heating before dicing. An adhesive sheet is provided.

According to the present invention, in a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition on a base film containing polyvinyl chloride and a polyester plasticizer, the pressure-sensitive adhesive composition is a (meth) acrylic ester. It contains 100 parts by weight of a copolymer and 0.01 to 5 parts by weight of an isocyanate curing agent. The (meth) acrylic acid ester copolymer contains 40 to 90% by weight of butyl (meth) acrylate units, methyl (meth A pressure-sensitive adhesive sheet having 5 to 55% by mass of acrylate units, 0.1 to 10% by mass of monomer units having a hydroxyl group, and a weight average molecular weight of 400,000 to 1,000,000 is provided.

The inventors of the present invention conducted intensive research to solve the problem of deterioration of pick-up property of the chip over time, and used a pressure-sensitive adhesive composition based on a (meth) acrylate copolymer as a base resin, and It has been found that by using a polyester plasticizer as the plasticizer, deterioration of the chip pick-up property over time can be prevented.
Furthermore, when we studied to develop a pressure-sensitive adhesive sheet that can be used in both the unheated production line and the heated production line, the (meth) acrylic acid ester copolymer of the above composition was used as the base resin, When the isocyanate curing agent of the above content is included and the content of the epoxy curing agent is limited to the above range, both chip retention and pick-up properties are improved regardless of the presence or absence of heating. As a result, the present invention has been completed.

A particularly important point in the present invention is that only a combination of a (meth) acrylic acid ester copolymer of a specific composition and a curing agent of a specific composition is good for both chip retention and pick-up properties regardless of whether there is heating or not. In other words, a pressure-sensitive adhesive sheet having excellent properties can be obtained. The present inventors conducted experiments with combinations of (meth) acrylic acid ester copolymers of various compositions and curing agents of various compositions, and the composition of either copolymer or curing agent is within the above range. When it came off, since the chip holding property and / or pick-up property when there was no heating and / or heating was deteriorated, a desired pressure-sensitive adhesive sheet could not be obtained.

Hereinafter, various embodiments of the present invention will be exemplified. The following embodiments can be combined with each other.
Preferably, in the (meth) acrylic acid ester copolymer, the butyl (meth) acrylate unit is 50 to 80% by mass, and the methyl (meth) acrylate unit is 15 to 45% by mass.
Preferably, the monomer having a hydroxyl group is 2-hydroxyethyl acrylate.
Preferably, the base film contains 25 to 45 parts by mass of a polyester plasticizer with respect to 100 parts by mass of polyvinyl chloride.
Preferably, the polyester plasticizer is an adipic acid polyester.
Preferably, the pressure-sensitive adhesive sheet is a dicing tape, and the dicing tape is (a) an affixing step of adhering the dicing tape to a semiconductor wafer or substrate and a ring frame, and (b) a semiconductor by dicing the semiconductor wafer or substrate. An electronic device including a dicing process for forming a chip or a semiconductor component, (c) an expanding process for stretching the adhesive sheet to widen the distance between the semiconductor chips or the semiconductor parts, and (d) a pickup process for picking up the semiconductor chip or the semiconductor component from the adhesive sheet. Used in parts manufacturing process.
Preferably, the method further includes a heating step of heating the adherend to which the pressure-sensitive adhesive sheet has been attached after the attaching step and before the dicing step to 60 to 100 ° C.

In this specification, the monomer unit means a structural unit derived from a monomer. Unless otherwise indicated, parts and% in this specification are based on mass. In this specification, (meth) acrylate is a general term for acrylate and methacrylate. Similarly, a compound containing (meth) such as (meth) acrylic acid is a general term for a compound having “meth” and a compound not having it.

The pressure-sensitive adhesive sheet of one embodiment of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition on a base film containing polyvinyl chloride and a polyester-based plasticizer. 100 parts of a meth) acrylate ester copolymer and 0.01 to 5 parts of an isocyanate-based curing agent, and the (meth) acrylate ester copolymer contains 50 to 80% by mass of butyl (meth) acrylate units, It contains 15 to 45% of methyl (meth) acrylate units and 0.1 to 10% of monomer units having hydroxyl groups.

<1. Base Film>
As the base film, a film containing polyvinyl chloride and a polyester plasticizer as a plasticizer for polyvinyl chloride is used. Examples of the polyester plasticizer include dicarboxylic acids such as aliphatic dicarboxylic acids having 2 to 10 carbon atoms such as adipic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, and / or aromatic dicarboxylic acids. Examples thereof include polyesters obtained by polycondensation of an acid and a glycol having 2 to 10 carbon atoms such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, hexanediol and the like. As the dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid are preferable, and adipic acid is particularly preferable in terms of versatility, cost, and stability over time. As the glycol, either a straight chain or a side chain can be used and is appropriately selected as necessary. The glycol preferably has 2 to 6 carbon atoms. The number average molecular weight of the polyester plasticizer is not particularly limited, but usually about 500 to 4000 is used. The polyester plasticizer is preferably 25 to 45 parts by mass, more preferably 30 to 40 parts by mass with respect to 100 parts by mass of polyvinyl chloride.

In addition, various additives such as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, and coloring agents such as dyes and pigments can be added to the base film as necessary. These additives are used in normal amounts depending on the type.

Further, these additives will be described. The antioxidant is not particularly limited as long as it is known as an antioxidant in conventional resins or resin compositions. Typical antioxidants include those generally used in the past, such as phenolic (monophenolic, bisphenolic, polymeric phenolic), sulfur, and phosphorus.

Examples of the ultraviolet absorber include salicylate-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based, and benzophenone-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers are particularly preferable from the viewpoint of the ultraviolet absorption effect. A benzotriazole-based ultraviolet absorber is preferred.

As the light stabilizer, for example, a light stabilizer such as a hindered amine or hindered phenol can be used. The addition amount of the light stabilizer is not particularly limited, and may be a commonly used amount.

The antistatic agent is not particularly limited, and examples thereof include a quaternary amine salt monomer. Examples of the quaternary amine salt monomer include dimethylaminoethyl (meth) acrylate quaternary chloride, diethylaminoethyl (meth) acrylate quaternary chloride, methylethylaminoethyl (meth) acrylate quaternary chloride, p- Examples thereof include dimethylaminostyrene quaternary chloride and p-diethylaminostyrene quaternary chloride, and dimethylaminoethyl methacrylate quaternary chloride is preferably used.

The flame retardant is not particularly limited, for example, brominated flame retardants, inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, antimony trioxide, melamine cyanurate, urea, triazine ring-containing compounds including melamine derivatives, Organic flame retardants, such as phosphate esters, such as aromatic polyphosphate, are mentioned.

As the colorant, any of known or well-known colorants such as organic pigments, inorganic pigments, dyes, and carbon black can be used. The color is arbitrary and can be, for example, white, ivory, black, red, blue, yellow, green, and the like. When the film substrate has a multilayer structure, a colorant may be added to all layers, or a colorant may be added to only a part of the layers. Examples of pigments include, for example, phthalocyanine, azo, condensed azo, azo lake, anthraquinone, perylene / perinone, indigo / thioindigo, isoindolinone, azomethine azo, dioxazine, quinacridone, Organic pigments such as aniline black, triphenylmethane, carbon black, titanium oxide, iron oxide, iron hydroxide, chromium oxide, spinel firing, chromic acid, chromium vermilion, bitumen , Aluminum powder system, bronze powder system and the like. These pigments may be in any form, and these pigments may be subjected to various dispersion treatments by various known methods.

The thickness of the base film is not particularly limited and can be appropriately determined. For example, the thickness is 40 to 250 μm, preferably 50 to 200 μm, and more preferably 60 to 150 μm.

Examples of the base film forming method include a calendar forming method, a T-die extrusion method, an inflation method, and a casting method.

The base film may be subjected to an antistatic treatment on the pressure-sensitive adhesive contact surface and / or non-contact of the base film in order to prevent charging when the release film is peeled off. The antistatic agent may be kneaded into the resin. For the antistatic treatment, an antistatic agent such as a quaternary amine salt monomer can be used.

Examples of the quaternary amine salt monomer include dimethylaminoethyl (meth) acrylate quaternary chloride, diethylaminoethyl (meth) acrylate quaternary chloride, methylethylaminoethyl (meth) acrylate quaternary chloride, p- There are dimethylaminostyrene quaternary chloride and p-diethylaminostyrene quaternary chloride, and dimethylaminoethyl methacrylate quaternary chloride is preferred.

The method of using the slip agent and the antistatic agent is not particularly limited. For example, the adhesive may be applied to one side of the base film, and the slip agent and / or the antistatic agent may be applied to the back side thereof. Alternatively, an antistatic agent may be kneaded into the resin of the base film to form a sheet.

It is possible to laminate an adhesive on one side of the base film and make the other side an embossed surface with an average surface roughness (Ra) of 0.3 to 1.5 μm. By installing the embossed surface on the machine table side of the expanding device, the base film can be easily expanded in the expanding process after dicing.

In order to improve the expandability after dicing, a slipping agent can be applied to the adhesive non-contact surface of the base film, or a slipping agent can be kneaded into the base film.

The slip agent is not particularly limited as long as it is a substance that reduces the friction coefficient of the pressure-sensitive adhesive sheet and the expanding device. For example, silicone compounds such as silicone resins and (modified) silicone oils, fluororesins, hexagonal boron nitride, carbon black, And molybdenum disulfide. These friction reducing agents may mix a plurality of components. Since manufacture of an electronic component is performed in a clean room, it is preferable to use a silicone compound or a fluororesin. Among silicone compounds, a copolymer having a silicone macromonomer unit is particularly preferred because it has good compatibility with the antistatic layer and can achieve a balance between antistatic properties and expandability.

<2. Adhesive layer>
In the present embodiment, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer contains 100 parts by weight of a (meth) acrylic acid ester copolymer and 0.01 to 5 parts by weight of an isocyanate curing agent.

<2-1. (Meth) acrylic acid ester copolymer>
The (meth) acrylic acid ester copolymer has a butyl (meth) acrylate unit of 40 to 90%, a methyl (meth) acrylate unit of 5 to 55%, and a monomer unit having a hydroxyl group of 0.1 to 10%. It is a copolymer containing.

The butyl (meth) acrylate unit is 40 to 90%. If it falls below this range, the chip retainability deteriorates, and if it exceeds this range, the pick-up property falls. Further, it is more preferably 50 to 80%. Within this range, excellent performance can be exhibited in terms of both chip retention and pickup properties. Specifically, for example, 50, 55, 57.5, 60, 62.5, 65, 67.5, 70, 72.5, 75, 80%, between any two of the numerical values exemplified here It may be within the range.
The methyl (meth) acrylate unit is 5 to 55%. If it falls below this range, the pick-up property is lowered, and if it exceeds this range, the chip retainability is lowered. Further, it is more preferably 15 to 45%. Within this range, excellent performance can be exhibited in terms of both chip retention and pickup properties. Specifically, for example, it is 15, 20, 25, 30, 35, 40, 45%, and may be within a range between any two of the numerical values exemplified here.

Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxyvinyl ether. The monomer unit having a hydroxyl group is 0.1 to 10%. If it falls below this range, the chip retainability is lowered, and if it exceeds this range, the pickup property is lowered. More preferably, it is 1 to 7% by mass. Within this range, excellent performance can be exhibited in terms of both chip retention and pickup properties. Specifically, it is 1, 2, 3, 4, 5, 6, 7 mass%, for example, and may be in the range between any two of the numerical values exemplified here.

(Methods for producing a (meth) acrylic acid ester polymer include emulsion polymerization and solution polymerization).

<2-2. Isocyanate-based curing agent>
The isocyanate curing agent is 0.01 to 10 parts per 100 parts of the (meth) acrylic acid ester copolymer. If it falls below this range, the pick-up property decreases, and if it exceeds this range, the chip retainability deteriorates. More preferably, it is 0.1 to 5 parts. Within this range, excellent performance can be exhibited in terms of both chip retention and pickup properties. Specifically, for example, it is 0.1, 0.5, 1, 1.5, 2, 3, 4, 5 and may be within the range between any two of the numerical values exemplified here. .

As the isocyanate curing agent, a compound having a plurality of isocyanate groups is used. Examples of the compound having a plurality of isocyanate groups include aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates.

Examples of the aromatic isocyanate include tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, and xylylene diisocyanate.

Examples of the alicyclic isocyanate include isophorone diisocyanate and methylene bis (4-cyclohexyl isocyanate).

Examples of the aliphatic isocyanate include hexamethylene diisocyanate and trimethylhexamethylene diisocyanate.

These isocyanate compounds may be dimers or trimers, or may be adducts obtained by reacting with polyol compounds.

In the pressure-sensitive adhesive composition, a tackifying resin may be added to adjust the pressure-sensitive adhesive strength. The tackifying resin is not particularly limited. For example, rosin resin, rosin ester resin, terpene resin, terpene phenol resin, phenol resin, xylene resin, coumarone resin, coumarone indene resin, styrene resin, aliphatic petroleum resin, aromatic petroleum resin , Aliphatic aromatic copolymer petroleum resins, alicyclic hydrocarbon resins, and modified products, derivatives, hydrogenated products, and the like thereof.

The blending amount of the tackifying resin is not particularly limited, and is preferably 200 parts or less, preferably 30 parts or less, with respect to 100 parts of the (meth) acrylic acid ester copolymer.

<2-3. Additives>
Various additives such as a curing agent, a polymerization initiator, a softening agent, an anti-aging agent, a filler, an ultraviolet absorber, a light stabilizer, a photopolymerizable compound, and a photoinitiator are added to the pressure-sensitive adhesive composition. May be.

<3. Manufacture of adhesive sheet>
As a method of forming a pressure-sensitive adhesive layer on a base film and forming a pressure-sensitive adhesive sheet, for example, a method of directly applying a pressure-sensitive adhesive on a base film with a coater such as a gravure coater, comma coater, bar coater, knife coater or roll coater Alternatively, there is a method in which a pressure-sensitive adhesive is applied to a release film and bonded to a base film after drying. The pressure-sensitive adhesive composition may be printed on the substrate film by convex plate printing, concave plate printing, flat plate printing, flexographic printing, offset printing, screen printing, or the like.

The thickness of the pressure-sensitive adhesive layer is preferably 1 to 100 μm, and more preferably 5 to 40 μm. If the pressure-sensitive adhesive layer is thin, the adhesive strength is reduced, and chip retention during dicing and peeling from the ring frame may occur. If the pressure-sensitive adhesive layer is thick, the adhesive strength is high, and pickup failure may occur.

<4. Manufacture of electronic components>
Hereinafter, a method for manufacturing an electronic component using the above-described pressure-sensitive adhesive sheet will be described. This method includes a sticking step, a dicing step, and a pickup step, as will be described below. Further, a heating step is optionally provided after the pasting step and before the dicing step.
Hereinafter, each step will be described.

(1) Affixing process First, in an affixing process, an adhesive sheet is affixed on a to-be-adhered body and a ring frame. Examples of the adherend include a semiconductor wafer and a package substrate.

(2) Heating process Next, when the adhesiveness between a to-be-adhered body and an adhesive sheet is not favorable, in order to improve both adhesiveness, a heating process is performed. The heating step can be performed by heating the adherend to 60 to 100 ° C.

(3) Dicing Step Next, in the dicing step, the adherend is diced into a chip with the adherend attached to the adhesive sheet. Each chip formed by dicing becomes an electronic component. Dicing can be performed using a dicing blade. Since the pressure-sensitive adhesive sheet is excellent in chip retention before irradiation with ultraviolet rays and / or radiation, it is possible to prevent the chips from peeling off (chip jumping) during dicing.

(4) Pickup Step Next, in the pickup step, the chip is picked up from the adhesive sheet after the dicing step. Specifically, this step can be performed, for example, by the following method. Ultraviolet rays and / or radiation (not shown) are irradiated from the base film side of the pressure-sensitive adhesive sheet, and then the pressure-sensitive adhesive sheet is radially expanded to widen the chip interval, and then the chip is pushed up with a needle or the like (not shown). Then, the chip is picked up by a vacuum collet or air tweezers (not shown) and picked up. A well-known thing can be used for the light source of an ultraviolet-ray and / or a radiation. There are low-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, and metal halide lamps as ultraviolet light sources. As the radiation, electron beams, α rays, β rays, and γ rays are preferably used.

By irradiating with ultraviolet rays and / or radiation, the vinyl group in the pressure-sensitive adhesive composition can be three-dimensionally reticulated to reduce the pressure-sensitive adhesive strength of the pressure-sensitive adhesive composition. Thereby, before irradiating with ultraviolet rays and / or radiation, since the pressure-sensitive adhesive composition has an initial high adhesive force, it can exhibit excellent chip retention, and after being irradiated with ultraviolet rays and / or radiation. Since the adhesive strength of the pressure-sensitive adhesive composition is reduced, the pick-up property of the chip can be improved.

The chip picked up in the pick-up process can be mounted on a lead frame or a circuit board.

The pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet according to Examples and Comparative Examples were produced with the following prescription. Tables 1 and 2 show the main formulations and the results of each experimental example.

The numerical values for the compositions in Tables 1 and 2 represent parts by mass. The numerical value about a plasticizer represents the mass part of a plasticizer when a polyvinyl chloride resin is 100 parts. The numerical value about a crosslinking agent represents the mass part of a crosslinking agent when a (meth) acrylic acid ester copolymer is 100 parts. Details of the plasticizer and the curing agent are as follows.
Adipic acid polyester: manufactured by Dainippon Ink & Chemicals, Inc., trade name: Polycizer W2310, number average molecular weight 2300
・ Terephthalic acid polyester: Commercial product (polyethylene terephthalate)
・ Isocyanate-based curing agent: Trimethylolpropane adduct of 2,4-tolylene diisocyanate, commercial product

First, a polyvinyl chloride resin, a plasticizer shown in Tables 1 and 2, and other stabilizers, pigments and fillers were blended. This resin mixture was kneaded with a Banbury mixer and then formed into a thickness of 70 μm by calendering to obtain a base film.

Next, the pressure-sensitive adhesive composition having the composition shown in Tables 1 and 2 was applied onto a PET release film so that the thickness of the pressure-sensitive adhesive layer after drying was 15 μm, and the pressure-sensitive adhesive sheet was laminated on the base film. Obtained. The following evaluation was performed about the obtained adhesive sheet.

(1) Evaluation of increase in adhesive strength over time Adhesive sheet is attached to a mirror surface of a silicon wafer, and then pressed with one reciprocation of a 2 kg roller and left for 20 minutes. Then, adhesive is applied under conditions of a 180 ° peel and a pulling speed of 300 mm / min. The force was measured. As the silicon wafer, a 725 μm thick wafer (6 inches) was used.
In addition, a test specimen that was allowed to stand for 7 days after pressure bonding under the above conditions was prepared, and the adhesive strength of this test specimen was also measured in the same manner. The rate of increase was determined from the adhesive strength (X) of the specimen left for 20 minutes and the adhesive strength (Y) of the specimen left for 7 days according to the following formula.
Rate of increase = (100 × (Y−X)) / X

From the calculated rate of increase, the increase in adhesive strength over time was evaluated according to the following criteria.
◎ (excellent): The rate of increase is less than 5%. ○ (Good): The rate of increase is 5% or more and less than 10%.

(2) Evaluation of chip holding property and pick-up property The obtained adhesive sheet was bonded to a ring frame and a silicon wafer having a diameter of 8 inches and a thickness of 0.1 mm on which a dummy circuit pattern was formed. Then, when heating, it heated in oven at 75 degreeC for 30 minutes. Thereafter, dicing and pick-up processes were performed.

The conditions for the dicing process were as follows.
Dicing machine: DAD341 manufactured by DISCO
Dicing blade: NBC-ZH205O-27HEEE made by DISCO
Dicing blade shape: outer diameter 55.56 mm, blade width 35 μm, inner diameter 19.05 mm
Dicing blade rotation speed: 40,000 rpm
Dicing blade feed rate: 50 mm / sec. Dicing size: 1.5 mm square. Cutting depth into adhesive sheet: 15 μm
Cutting water temperature: 25 ° C
Cutting water volume: 1.0 l / min

The conditions for the pick-up process were as follows.
Pickup device: CAP-300II manufactured by Canon Machinery
Expanding amount: 8mm
Needle pin shape: 70μmR
Number of needle pins: 1 Needle pin push-up height: 1.5 mm

The following evaluation was performed in the dicing process and the pickup process.

(2-1) Chip Retention The chip retention was evaluated according to the following criteria based on the remaining ratio of the semiconductor chips held on the adhesive sheet after the dicing process.
◎ (Excellent): Chip skipping is less than 5% ○ (Good): Chip skipping is 5% or more and less than 10% × (Not possible): Chip skipping is 10% or more

(2-2) Pickup property Pickup property was evaluated according to the following criteria based on the rate at which a semiconductor chip could be picked up in the pickup process.
◎ (Excellent): Chip pickup success rate is 95% or more ○ (Good): Chip pickup success rate is 80% or more and less than 95% × (Not possible): Chip pickup success rate is less than 80%

As is clear from Tables 1 and 2, in all Examples, the increase in adhesive strength with time was small, and excellent results were obtained in both chip holding property and pick-up property regardless of the presence or absence of heating.
When Example 1 and Example 20 were compared, it was found that when an adipic acid-based polyester was used, the increase in adhesive strength with time was particularly small.
In Comparative Examples 1 to 4, the types of monomer units constituting the (meth) acrylic acid ester copolymer were the same as those in the Examples, but the ratio was not appropriate, so good results could not be obtained. .
In Comparative Examples 5 to 6, the types and composition ratios of the monomer units constituting the (meth) acrylic acid ester copolymer are the same as those in Examples, but the ratio of the weight average molecular weight was not appropriate, No result was obtained.
In Comparative Examples 7 to 8, the types and composition ratios of the monomer units constituting the (meth) acrylic acid ester copolymer are the same as those in the example, but the ratio of the isocyanate curing agent was not appropriate, so that it was good. Results were not obtained.
In Comparative Example 9, since a non-polyester plasticizer was used, the increase in adhesive strength with time was large.

In the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition on a base film containing polyvinyl chloride and a polyester plasticizer, the pressure-sensitive adhesive composition is a (meth) acrylic ester. 100 parts by weight of the copolymer and 0.01 to 5 parts by weight of an isocyanate curing agent. The (meth) acrylic acid ester copolymer has a methyl (meth) acrylate unit of 5 to 55% by weight and a hydroxyl group. It can also be expressed as a pressure-sensitive adhesive sheet containing 0.1 to 10% by mass of monomer units, the remainder containing butyl (meth) acrylate and inevitable impurities, and having a weight average molecular weight of 400,000 to 1,000,000. .

Claims (7)

In a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition on a base film containing polyvinyl chloride and a polyester plasticizer,
The pressure-sensitive adhesive composition contains 100 parts by weight of a (meth) acrylic acid ester copolymer and 0.01 to 5 parts by weight of an isocyanate curing agent,
The (meth) acrylic acid ester copolymer is
40 to 90% by mass of butyl (meth) acrylate unit,
5 to 55% by mass of methyl (meth) acrylate unit,
0.1 to 10% by mass of a monomer unit having a hydroxyl group,
The weight average molecular weight is 400,000 to 1 million,
Adhesive sheet. The pressure-sensitive adhesive sheet according to claim 1, wherein in the (meth) acrylic acid ester copolymer, the butyl (meth) acrylate unit is 50 to 80% by mass, and the methyl (meth) acrylate unit is 15 to 45% by mass. . The pressure-sensitive adhesive sheet according to claim 1, wherein the monomer having a hydroxyl group is 2-hydroxyethyl acrylate. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the base film contains 25 to 45 parts by mass of a polyester plasticizer with respect to 100 parts by mass of polyvinyl chloride. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the polyester plasticizer is an adipic acid-based polyester. The pressure-sensitive adhesive sheet is a dicing tape, and the dicing tape is
(A) A sticking step of attaching a dicing tape to a semiconductor wafer or substrate and a ring frame;
(B) a dicing step of dicing a semiconductor wafer or substrate into a semiconductor chip or a semiconductor component;
(C) an expanding step of stretching the adhesive sheet to widen the gap between the semiconductor chips or semiconductor components;
(D) a pickup step of picking up a semiconductor chip or semiconductor component from the adhesive sheet;
Used in the manufacturing process of electronic components including
The pressure-sensitive adhesive sheet according to any one of claims 1 to 5. The electronic device according to claim 6, further comprising a heating step of heating the adherend to which the pressure-sensitive adhesive sheet is attached after the attaching step and before the dicing step to 60 to 100 ° C. A manufacturing method for parts.