WO2012017568A1

WO2012017568A1 - Adhesive film and tape for semiconductor wafer processing

Info

Publication number: WO2012017568A1
Application number: PCT/JP2010/070073
Authority: WO
Inventors: 真沙美青山; 石渡　伸一; 泰正盛島
Original assignee: 古河電気工業株式会社
Priority date: 2010-08-05
Filing date: 2010-11-11
Publication date: 2012-02-09
Also published as: CN102511077B; KR101143109B1; TW201207072A; CN102511077A; KR20120023595A; TWI425069B

Abstract

Provided are a pressure-sensitive film and tape for semiconductor wafer processing, which are capable of reducing the occurrence of reflow cracks in packages, even if a package is picked up in a state in which a pressure-sensitive adhesive is attached to an adhesive layer. This pressure-sensitive film comprises a base film and a pressure-sensitive adhesive layer disposed on said base film, and is used to process semiconductor wafers. The loss in weight of the pressure-sensitive adhesive layer at the reflow temperature, as measured by differential thermal analysis, is not more than 1.5%. Furthermore, this tape for semiconductor wafer processing has a pressure-sensitive film comprising a base layer and a pressure-sensitive adhesive layer disposed on said base layer, and an adhesive layer disposed on the pressure-sensitive adhesive layer. The loss in weight of pressure-sensitive adhesive layer at the reflow temperature, as measured by differential thermal analysis, is not more than 1.5%.

Description

Adhesive film and tape for semiconductor wafer processing

The present invention relates to an adhesive film and a semiconductor wafer processing tape used to manufacture a semiconductor device by cutting a semiconductor wafer into semiconductor chips.

As a semiconductor wafer processing tape used in the manufacturing process of a semiconductor device, a semiconductor wafer processing tape having a structure in which an adhesive layer (die bonding film) is laminated on an adhesive film (dicing tape) has been proposed (for example, Has already been put into practical use.

In the manufacturing process of a semiconductor device, after a semiconductor wafer processing tape is attached to a semiconductor wafer, the semiconductor wafer is cut (diced) into chips using a dicing blade, the semiconductor wafer processing tape is expanded, A step of picking up the cut chip from the adhesive layer together with the adhesive layer, a step of mounting the chip on the substrate via the adhesive layer attached to the chip, a reflow furnace after sealing the chip adhered to the substrate etc. The step of passing through is performed.

Japanese Patent Laid-Open No. 02-32181

However, in the semiconductor wafer processing tape described in the above-mentioned Patent Document 1, if the time during which the pressure-sensitive adhesive layer and the adhesive layer are in contact with each other during the period from manufacture to use becomes long, both layers become familiar before use. When picking up the cut chip, the pressure-sensitive adhesive may be picked up in a state where it adheres to the adhesive layer. In such a state, if the chip bonded to the substrate or the like is sealed and then passed through a reflow furnace, there is a problem that reflow cracks may occur.

Therefore, an object of the present invention is to reflow cracks in the package even when the adhesive layer is familiar with the adhesive layer and the chip is picked up while the adhesive is attached to the adhesive layer. An object of the present invention is to provide a pressure-sensitive adhesive film and a semiconductor wafer processing tape that can reduce the occurrence.

In order to solve the above problems, the pressure-sensitive adhesive film of the present invention comprises a base film and a pressure-sensitive adhesive layer provided on the base film, and is a pressure-sensitive adhesive film used for processing a semiconductor wafer, which has a differential heat. The weight loss of the pressure-sensitive adhesive layer at the reflow temperature measured by analysis is 1.5% or less.

The pressure-sensitive adhesive layer at 260 ° C. comprises a base film and a pressure-sensitive adhesive layer provided on the base film, and is used for processing a semiconductor wafer, and is measured by differential thermal analysis. The weight loss is 1.5% or less.

Moreover, in order to solve the said subject, the tape for semiconductor wafer processing of this invention is provided on the adhesive film which consists of a base film and the adhesive layer provided on this base film, and the said adhesive layer. A tape for wafer processing having an adhesive layer, wherein the weight loss of the pressure-sensitive adhesive layer at the reflow temperature measured by differential thermal analysis is 1.5% or less.

Moreover, the semiconductor wafer processing tape of the present invention has a pressure-sensitive adhesive film comprising a base film and a pressure-sensitive adhesive layer provided on the base film, and an adhesive layer provided on the pressure-sensitive adhesive layer. A tape for wafer processing, wherein the weight loss of the pressure-sensitive adhesive layer at 260 ° C. measured by differential thermal analysis is 1.5% or less.

The semiconductor wafer processing tape of the present invention is characterized in that the pressure-sensitive adhesive layer has a weight average molecular weight of 1 million or more.

In the semiconductor wafer processing tape of the present invention, the pressure-sensitive adhesive layer contains a photopolymerization initiator, and the thermal decomposition start temperature of the photopolymerization initiator is 260 ° C. or higher.

The pressure-sensitive adhesive film and the semiconductor wafer processing tape of the present invention reduce the occurrence of reflow cracks in the package even when the pressure-sensitive adhesive is picked up while adhering to the adhesive layer when picking up the chip. be able to.

It is sectional drawing which shows an example of the tape for semiconductor wafer processing of this invention. (A) is sectional drawing which shows the state by which the semiconductor wafer W and the ring frame were bonded together on the semiconductor wafer processing tape, (b) is sectional drawing which shows the semiconductor wafer processing tape and semiconductor wafer after dicing (C) is a sectional view showing a semiconductor wafer processing tape and a semiconductor wafer after expansion.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the semiconductor wafer processing tape 15 according to the present embodiment has an adhesive film 14 in which an adhesive layer 12 is laminated on a base film 11. It is a dicing die bonding film in which an adhesive layer 13 is laminated. The pressure-sensitive adhesive layer 12 and the adhesive layer 13 may be cut (pre-cut) into a predetermined shape in advance according to the use process and the apparatus. When the adhesive layer 13 pre-cut according to the wafer W (see FIG. 2A) is laminated, the adhesive layer 13 is present at the portion where the wafer W is bonded, and the ring frame 20 for dicing (FIG. 2). There is no adhesive layer 13 in the portion where (a) is attached, and only the pressure-sensitive adhesive layer 12 is present. In general, since the adhesive layer 13 is difficult to peel off from the adherend, the ring frame 20 can be bonded to the pressure-sensitive adhesive layer 12 by using the pre-cut adhesive layer 13, and the ring frame 20 after use is used. The effect that it is hard to produce the adhesive residue on is obtained. Moreover, the semiconductor wafer processing tape 15 of the present invention includes a form in which the wafer is cut and laminated for each wafer, and a form in which a plurality of long sheets formed by winding the wafer are wound into a roll. Below, the base film 11, the adhesive layer 12, and the adhesive layer 13 are each demonstrated in detail.

<Base film>
Although it does not specifically limit as a material which comprises a base film, It is preferable to be selected from polyolefin and polyvinyl chloride. The surface roughness Ra of the surface in contact with the adhesive is preferably 1 μm or less, more preferably 0.5 μm or less. By making the surface roughness Ra 1 μm or less, the contact area with the pressure-sensitive adhesive can be increased, and the pressure-sensitive adhesive can be prevented from peeling off from the base film.

Examples of the polyolefin include polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid. Examples thereof include homopolymers or copolymers of α-olefins such as methyl copolymers, ethylene-acrylic acid copolymers, and ionomers, or mixtures thereof.

In the case of using a type that is cured by radiation irradiation and has a reduced adhesive strength as an adhesive layer to be described later, the substrate film is preferably radiation transmissive. The thickness of the base film is preferably 50 to 300 μm from the viewpoint of ensuring strength and chip pick-up properties. Further, the base film may be a single layer or may be composed of a plurality of layers.

<Adhesive layer>
The pressure-sensitive adhesive layer can be produced by applying a pressure-sensitive adhesive on the base film. There is no restriction | limiting in particular as an adhesive layer, What is necessary is just to have the property that an adhesive layer and a semiconductor wafer do not exfoliate at the time of an expansion, and the characteristic which is easy to exfoliate from an adhesive layer at the time of pick-up. In order to improve the pickup property, the pressure-sensitive adhesive layer is preferably radiation-curable.

For example, known chlorinated polypropylene resins, acrylic resins, polyester resins, polyurethane resins, epoxy resins, addition reaction type organopolysiloxane resins, silicon acrylate resins, ethylene-vinyl acetate copolymers, ethylene- Radiation polymerization of ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, various elastomers such as polyisoprene, styrene / butadiene copolymer and hydrogenated products, and mixtures thereof It is preferable to prepare a pressure-sensitive adhesive by appropriately mixing an adhesive compound. Various surfactants and surface smoothing agents may be added. The thickness of the pressure-sensitive adhesive layer is not particularly limited and may be appropriately set, but is preferably 1 to 30 μm.

The polymerizable compound is, for example, a low molecular weight compound having at least two photopolymerizable carbon-carbon double bonds in a molecule that can be three-dimensionally reticulated by light irradiation, or a photopolymerizable carbon-carbon double bond group as a substituent. Polymers and oligomers possessed by Specifically, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6 hexanediol diacrylate For example, acrylate, polyethylene glycol diacrylate, oligoester acrylate, silicon acrylate, etc., acrylic acid, copolymers of various acrylic esters, and the like are applicable.

In addition to the above acrylate compounds, urethane acrylate oligomers can also be used. Urethane acrylate oligomers include polyester compounds or polyether compounds such as polyol compounds and polyisocyanate compounds (for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diene). A terminal isocyanate urethane prepolymer obtained by reacting isocyanate, 1,4-xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc.) with an acrylate or methacrylate having a hydroxyl group (for example, 2-hydroxyethyl) Acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, etc.) Obtained by the reaction. The pressure-sensitive adhesive layer may be a mixture of two or more selected from the above resins. The above-mentioned pressure-sensitive adhesive materials have a molecular structure with as many nonpolar groups as possible, such as a trifluoromethyl group, a dimethylsilyl group, and a long-chain alkyl group, with a surface free energy of 40 mJ / m ² or less. It is desirable to include.

In addition, the resin for the pressure-sensitive adhesive layer contains, as appropriate, an acrylic pressure-sensitive adhesive, a photopolymerization initiator, a curing agent, etc. in addition to the radiation polymerizable compound that cures the pressure-sensitive adhesive layer by irradiating the base film with radiation. An adhesive can also be prepared.

When using a photopolymerization initiator, for example, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michler's ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, benzyldimethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenyl Propane or the like can be used. The blending amount of these photopolymerization initiators is preferably 0.01 to 30 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

In addition, if low molecular components are present in the pressure-sensitive adhesive, the low-molecular components may migrate to the surface of the pressure-sensitive adhesive layer during storage for a long time after production of the base film, which may impair the adhesive properties. The gel fraction is desirably high and is usually 60% or more, preferably 70% or more. Here, a gel fraction means what is calculated as follows. About 0.05 g of the pressure-sensitive adhesive layer is weighed and immersed in 50 ml of xylene at 120 ° C. for 24 hours, filtered through a 200 mesh stainless steel wire mesh, and the insoluble matter on the wire mesh is dried at 110 ° C. for 120 minutes. Next, the mass of the dried insoluble matter is weighed, and the gel fraction is calculated by the following formula 1.
Gel fraction (%) = (mass of insoluble matter / mass of weighed pressure-sensitive adhesive layer) × 100 (Formula 1)

The pressure-sensitive adhesive layer has a weight loss of 1.5% or less at the reflow temperature measured by differential thermal analysis (TG-DTA). Here, the reflow temperature is the peak temperature (Tp: peak package body temperature) of the package body, and the semiconductor engineering association (JEDEC: Joint Electron Device Engineering Council) defines the classification temperature (Tc: classification temperature). Uses the classification temperature as the peak temperature. The weight reduction of the pressure-sensitive adhesive layer is a weight reduction of the pressure-sensitive adhesive layer in a state where reflow is performed. That is, in the case of a radiation-curable pressure-sensitive adhesive layer, reflow is performed after irradiation and curing, so that the weight loss when the pressure-sensitive adhesive in this state is heated at the reflow temperature for a required time is 1. 5% or less. If the weight loss when heated for the required time at the reflow temperature of the pressure-sensitive adhesive layer is 1.5% or less, even if reflow is performed with the pressure-sensitive adhesive attached to the adhesive layer, the pressure-sensitive adhesive will be thermally decomposed. The accompanying outgas generation is suppressed. As a result, the occurrence of reflow cracks can be reduced. Since the reflow temperature of lead-free solder is about 260 ° C., the weight loss at 260 ° C. of the pressure-sensitive adhesive layer measured by differential thermal analysis (TG-DTA) is preferably 1.5% or less.

In order to suppress weight loss due to heating of the pressure-sensitive adhesive, the glass transition temperature Tg of the base polymer of the pressure-sensitive adhesive is set to −50 ° C. or higher, or the weight average molecular weight of the pressure-sensitive adhesive layer is set to 1 million or higher. Good. Furthermore, you may combine making the decomposition temperature of a photoinitiator 260 degreeC or more.

<Adhesive layer>
When the chip is picked up after the semiconductor wafer is bonded and cut, the adhesive layer is peeled off from the adhesive layer and attached to the chip, and the chip is attached to the package substrate or lead frame. It functions as a bonding film when it is fixed to.

The adhesive layer is a film in which an adhesive is formed in advance. For example, a known polyimide resin, polyamide resin, polyetherimide resin, polyamideimide resin, polyester resin, polyesterimide resin, phenoxy resin used for adhesives , Polysulfone resin, polyether sulfone resin, polyphenylene sulfide resin, polyether ketone resin, chlorinated polypropylene resin, acrylic resin, polyurethane resin, epoxy resin, polyacrylamide resin, melamine resin and the like, and mixtures thereof can be used. In order to improve the dividing property of the adhesive layer 13, it is preferable that the acrylic copolymer and the epoxy resin are included, and the acrylic copolymer has a Tg of 10 ° C. or higher. Furthermore, it is preferable to contain 50% or more of an inorganic filler. Moreover, in order to reinforce the adhesive force with respect to a chip | tip or a lead frame, it is desirable to add a silane coupling agent or a titanium coupling agent to the said material and its mixture as an additive. The thickness of the adhesive layer is not particularly limited, but is usually preferably about 5 to 100 μm.

The epoxy resin is not particularly limited as long as it cures and exhibits an adhesive action, but an epoxy resin having two or more functional groups, preferably having a molecular weight of less than 5000, more preferably less than 3000 can be used. Further, an epoxy resin having a molecular weight of preferably 500 or more, more preferably 800 or more can be used.

For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy Resin, diglycidyl etherified product of biphenol, diglycidyl etherified product of naphthalenediol, diglycidyl etherified product of phenol, diglycidyl etherified product of alcohol, and alkyl-substituted products, halides, hydrogenated products, etc. And a novolak-type epoxy resin. Moreover, what is generally known, such as a polyfunctional epoxy resin and a heterocyclic ring-containing epoxy resin, can also be applied. These can be used alone or in combination of two or more. Furthermore, components other than the epoxy resin may be included as impurities within a range that does not impair the characteristics.

As the acrylic copolymer, for example, an epoxy group-containing acrylic copolymer can be used. The epoxy group-containing acrylic copolymer contains 0.5 to 6% by weight of glycidyl acrylate or glycidyl methacrylate having an epoxy group. In order to obtain a high adhesive strength, 0.5% by weight or more is preferable, and gelation can be suppressed if it is 6% by weight or less.

The amount of glycidyl acrylate or glycidyl methacrylate used as the functional group monomer is a copolymer ratio of 0.5 to 6% by weight. That is, in the present invention, the epoxy group-containing acrylic copolymer refers to a copolymer obtained by using glycidyl acrylate or glycidyl methacrylate as a raw material in an amount of 0.5 to 6% by weight based on the obtained copolymer. . The remainder can be a mixture of an alkyl acrylate having 1 to 8 carbon atoms such as methyl acrylate or methyl methacrylate, an alkyl methacrylate, and styrene or acrylonitrile. Among these, ethyl (meth) acrylate and / or butyl (meth) acrylate are particularly preferable. The mixing ratio is preferably adjusted in consideration of the Tg of the copolymer. There is no restriction | limiting in particular in a polymerization method, For example, pearl polymerization, solution polymerization, etc. are mentioned, A copolymer is obtained by these methods. The weight average molecular weight of the epoxy group-containing acrylic copolymer is 100,000 or more, and if it is in this range, the adhesiveness and heat resistance are high, preferably 300,000 to 3,000,000, and 500,000 to 2,000,000. Is more preferable. If it is 3 million or less, the flowability is lowered, and thus the possibility that the filling property to the wiring circuit formed on the support member to which the semiconductor element is attached is lowered as required can be reduced.
In addition, in this specification, a weight average molecular weight is a polystyrene conversion value using the calibration curve by a standard polystyrene by the gel permeation chromatography method (GPC).

There are no particular restrictions on the inorganic filler. For example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, nitriding Examples thereof include boron, crystalline silica, and amorphous silica. These may be used alone or in combination of two or more. In order to improve thermal conductivity, aluminum oxide, aluminum nitride, boron nitride, crystalline silica, amorphous silica and the like are preferable. Silica is preferable from the viewpoint of balance of properties.

The average particle size of the filler is preferably 0.002 to 2 μm, more preferably 0.008 to 0.5 μm, and still more preferably 0.01 to 0.05 μm. If the average particle size of the filler is less than 0.002 μm, the wettability to the adherend tends to decrease, and the adhesion tends to decrease. If the average particle size exceeds 2 μm, the reinforcing effect due to the addition of the filler decreases and the heat resistance decreases. Tend to. Here, the average particle diameter means an average value obtained from the particle diameters of 100 fillers measured by TEM, SEM or the like.

Next, a method for manufacturing a semiconductor chip with an adhesive layer using the semiconductor wafer processing tape 15 of the present invention shown in FIG. 1 will be described with reference to FIG.

(Bonding process)
First, as shown in FIG. 2A, the back surface of the semiconductor wafer W is bonded to the adhesive layer 13 of the semiconductor wafer processing tape 15, and the ring frame 20 is bonded to a predetermined position of the adhesive layer 12.

(Dicing process)
The wafer processing tape 15 is sucked and supported from the surface of the base film 12 by the suction stage 22, and the semiconductor wafer W is mechanically cut using a blade (not shown) and divided into a plurality of semiconductor chips C (FIG. 2). (B)). At this time, the adhesive layer 13, the pressure-sensitive adhesive layer 12, and a part of the base film 11 are also appropriately diced.

(Irradiation process)
Then, the pressure-sensitive adhesive layer 12 is cured by irradiating the pressure-sensitive adhesive layer 12 with radiation from the lower surface of the base film 11. Since the adhesive force of the cured adhesive layer 12 is reduced, the adhesive layer 13 on the adhesive layer 12 can be peeled off. When the pressure-sensitive adhesive layer is composed of a plurality of layers, it is not necessary to cure the entire pressure-sensitive adhesive layer in order to peel the adhesive layer 13 from the pressure-sensitive adhesive layer 12, and at least the pressure-sensitive adhesive layer portion corresponding to the wafer is formed. It may be cured.

(Expanding process)
After the irradiation step, the semiconductor wafer processing tape 15 holding the plurality of divided semiconductor chips C is placed on the stage 21 of the expanding apparatus. Then, as shown in FIG. 2C, the hollow cylindrical push-up member 23 is raised from the lower surface side of the semiconductor wafer processing tape 15, and the base film 11 is moved in the radial direction and the circumferential direction of the ring frame 20. Enlarge.

(Pickup process)
After carrying out the expanding step, a picking up step for picking up the chip C is carried out with the adhesive film expanded. Specifically, the chip is pushed up from the lower side of the adhesive film 14 by a pin (not shown), and the chip C is adsorbed by an adsorption jig (not shown) from the upper surface side of the adhesive film 14 so as to be separated into individual pieces. The chip C is picked up together with the adhesive layer 13.

(Die bonding process)
Then, after performing the pickup process, the die bonding process is performed. Specifically, the semiconductor chip is bonded to a lead frame, a package substrate, or the like by an adhesive layer picked up together with the chip C in the pickup process.

(Reflow process)
After sealing the substrate on which the semiconductor chip is placed with a sealing material, the solder such as a solder ball disposed on the semiconductor chip is melted and the semiconductor chip and the substrate are connected with each other through a reflow furnace. A semiconductor device is obtained. Here, the pressure-sensitive adhesive layer was 1.5% or less in weight loss of the pressure-sensitive adhesive layer at the reflow temperature measured by differential thermal analysis, so that the reflow was performed with the pressure-sensitive adhesive attached to the adhesive layer. Moreover, generation | occurrence | production of the outgas accompanying thermal decomposition of an adhesive is suppressed.

As described above, when the chip is picked up, even if the pressure-sensitive adhesive is picked up in a state of adhering to the adhesive layer, the occurrence of reflow cracks in the package can be reduced.

Next, examples of the present invention will be described, but the present invention is not limited to these examples.

First, after preparing the pressure-sensitive adhesive compositions 1 to 9, the pressure-sensitive adhesive composition was adhered onto a 100 μm-thick ethylene-vinyl acetate copolymer film (base film) so that the thickness after drying of the pressure-sensitive adhesive composition was 10 μm. Agent compositions 1 to 9 were applied, dried at 110 ° C. for 3 minutes, and then allowed to stand in an environment of 23 ± 5 ° C. and 45% for 3 weeks to obtain an adhesive film. Next, adhesive compositions 1 and 2 were prepared, and the adhesive compositions 1 and 2 were applied to a release liner made of a polyethylene-terephthalate film from which the adhesive composition was released so that the thickness after drying was 20 μm. Each was coated and dried at 110 ° C. for 3 minutes to form an adhesive film. Then, the pressure-sensitive adhesive film and the adhesive film were cut into circles having a diameter of 370 mm and 320 mm, respectively, and the adhesive layer of the adhesive film was bonded to the pressure-sensitive adhesive layer side of the pressure-sensitive adhesive film in the combinations shown in Table 1, and Examples 1 to 6 and Dicing die bonding films according to Comparative Examples 1 to 3 were prepared. Hereinafter, methods for adjusting the pressure-sensitive adhesive compositions 1 to 8 and the adhesive compositions 1 to 2 will be described.

(Preparation of adhesive composition)
(Adhesive composition 1)
In 400 g of toluene as a solvent, 340 g of isooctyl acrylate, 13 g of methyl methacrylate, 60 g of hydroxy acrylate, 0.5 g of methacrylic acid, and a mixed solution of benzoyl peroxide as a polymerization initiator are appropriately adjusted in a dropping amount, and reaction temperature is added. And reaction time was adjusted and the solution of the compound (1) of the weight average molecular weight 800,000 was obtained. The Tg of compound (1) was measured by differential scanning calorimetry (DSC) and found to be −49 ° C. Subsequently, 2 parts by weight of Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a polyisocyanate is added to 100 parts by weight of the compound (1) in the solution to the compound (1) solution, and 300 wt. A pressure-sensitive adhesive composition 1 was obtained by adding parts and stirring.

(Adhesive composition 2)
To the solution of the above compound (1), 2.5 g of 2-isocyanatoethyl methacrylate as a compound having a radiation curable carbon-carbon double bond and a functional group and hydroquinone as a polymerization inhibitor were appropriately adjusted in the amount of dripping. In addition, the reaction temperature and reaction time were adjusted to obtain a solution of the compound (2) having a radiocurable carbon-carbon double bond. The Tg of compound (2) was measured by DSC and found to be -49 ° C. Subsequently, 2 parts by weight of Coronate L as a polyisocyanate is added to 100 parts by weight of the compound (2) in the solution to the solution of the compound (2), and Irgacure 184 (manufactured by Ciba Geigy Japan) is used as a photopolymerization initiator. 1 part by weight and 300 parts by weight of ethyl acetate as a solvent were added and stirred to obtain an adhesive composition 2.

(Adhesive composition 3)
In 400 g of toluene as a solvent, 340 g of isooctyl acrylate, 3 g of methyl methacrylate, 60 g of hydroxy acrylate, 0.5 g of methacrylic acid, and a mixed solution of benzoyl peroxide as a polymerization initiator are appropriately adjusted in a dropping amount, and reaction temperature is added. After adjusting the reaction time and obtaining a compound having a weight average molecular weight of 500,000, 2.5 g of 2-isocyanatoethyl methacrylate as a compound having a radiation curable carbon-carbon double bond and a functional group, and hydroquinone as a polymerization inhibitor Was added appropriately while adjusting the dropping amount, and the reaction temperature and reaction time were adjusted to obtain a solution of the compound (3) having a radiocurable carbon-carbon double bond. The Tg of compound (3) was measured by DSC and found to be -52 ° C. Subsequently, 0.7 parts by weight of coronate L as a polyisocyanate is added to 100 parts by weight of the compound (3) in the solution, and 1 part by weight of Irgacure 184 is used as a photopolymerization initiator. 300 parts by weight of ethyl acetate as a solvent was added and stirred to obtain an adhesive composition 3.

(Adhesive composition 4)
In 400 g of toluene, 443 g of n-butyl acrylate, 80 g of methyl methacrylate, 100 g of hydroxy acrylate, 7 g of methacrylic acid, and a mixed solution of benzoyl peroxide as a polymerization initiator are added in an appropriately adjusted drop amount, and the reaction temperature and reaction time are added. To obtain a compound having a weight average molecular weight of 200,000, then 2.5 g of 2-isocyanatoethyl methacrylate as a compound having a radiation curable carbon-carbon double bond and a functional group, and hydroquinone as a polymerization inhibitor, The addition amount was adjusted and the reaction temperature and reaction time were adjusted to obtain a solution of the compound (4) having a radiocurable carbon-carbon double bond. The Tg of compound (4) was measured by DSC and found to be -36 ° C. Subsequently, 0.5 parts by weight of coronate L as a polyisocyanate is added to 100 parts by weight of the compound (4) in the solution, and 1 part by weight of Irgacure 184 is used as a photopolymerization initiator. 300 parts by weight of ethyl acetate as a solvent was added and stirred to obtain an adhesive composition 4.

(Adhesive composition 5)
0.7 parts by weight of Coronate L as a polyisocyanate is added to 100 parts by weight of the compound (4) in the solution, and 1 part by weight of Irgacure 2959 as a photopolymerization initiator is used as a solvent. 300 parts by weight of ethyl acetate was added and stirred to obtain an adhesive composition 5.

(Adhesive composition 6)
In 400 g of toluene as a solvent, 200 g of lauryl acrylate, 100 g of 2-ethylhexyl acrylate, 10 g of methacrylic acid, and a mixed solution of benzoyl peroxide as a polymerization initiator are added by appropriately adjusting the dropping amount, and the reaction temperature and reaction time are adjusted. Then, after obtaining a compound having a weight average molecular weight of 800,000, 2.5 g of 2-isocyanatoethyl methacrylate as a compound having a radiation curable carbon-carbon double bond and a functional group, and hydroquinone as a polymerization inhibitor are appropriately added dropwise. Was added, and the reaction temperature and reaction time were adjusted to obtain a solution of the compound (5) having a radiocurable carbon-carbon double bond. The Tg of compound (5) was measured by DSC and found to be -20 ° C. Subsequently, 1 part by weight of Coronate L as a polyisocyanate was added to 100 parts by weight of the compound (5) in the solution, and 1 part by weight of Irgacure 907 was added as a photopolymerization initiator to the compound (5) solution. Agent composition 6 was obtained.

(Adhesive composition 7)
In 400 g of toluene as a solvent, 340 g of n-butyl acrylate, 70 g of hydroxy acrylate, 3.5 g of methacrylic acid, and a mixed solution of benzoyl peroxide as a polymerization initiator are added by appropriately adjusting the dropping amount, and the reaction temperature and reaction time are adjusted. After adjusting to obtain a compound having a weight average molecular weight of 900,000, 2.5 g of 2-isocyanatoethyl methacrylate as a compound having a radiation curable carbon-carbon double bond and a functional group, hydroquinone as a polymerization inhibitor, A solution of the compound (6) having a radiocurable carbon-carbon double bond was obtained by adjusting the dropping amount and adjusting the reaction temperature and reaction time. The Tg of compound (6) was measured by DSC and found to be -49 ° C. Subsequently, 1 part by weight of Irgacure 651 was added as a photopolymerization initiator to 100 parts by weight of the compound (6) in the solution to the solution of the compound (6) to obtain an adhesive composition 7.

(Adhesive composition 8)
A mixture of 340 g of n-butyl acrylate, 13 g of methyl methacrylate, 7 g of hydroxy acrylate, 0.5 g of methacrylic acid, and benzoyl peroxide as a polymerization initiator was added to 400 g of toluene as a solvent, and the reaction amount was appropriately adjusted. The temperature and reaction time were adjusted to obtain a solution of the compound (7) having a weight average molecular weight of 50,000. The Tg of compound (7) was measured by DSC and found to be -52 ° C. Subsequently, 2 parts by weight of coronate L as a polyisocyanate is added to 100 parts by weight of the compound (7) in the solution, and 300 parts by weight of ethyl acetate is added as a solvent to the solution of the compound (7). Composition 8 was obtained.

The thermal decomposition initiation temperature of each photopolymerization initiator was 260 ° C. or higher only for Irgacure 2959, and Irgacure 907, 651, and 184 were less than 260 ° C.

(Preparation of adhesive composition)
(Adhesive composition 1)
15 parts by weight of a cresol novolac type epoxy resin (epoxy equivalent 197, molecular weight 1200, softening point 70 ° C.) as an epoxy resin, 70 parts by weight of an acrylic resin (mass average molecular weight: 800,000, glass transition temperature −17 ° C.), phenol as a curing agent 15 parts by weight of novolak resin (hydroxyl equivalent 104, softening point 80 ° C.) and 1 part of Curesol 2PZ (trade name: 2-phenylimidazole, manufactured by Shikoku Kasei Co., Ltd.) as an accelerator are stirred in an organic solvent. An adhesive composition 1 was obtained.

(Adhesive composition 2)
5 parts by weight of a cresol novolac type epoxy resin (epoxy equivalent 197, molecular weight 1200, softening point 70 ° C.) as an epoxy resin, 0.5 part by mass of 3-glycidoxypropyltrimethoxysilane as an silane coupling agent, an average particle size of 1. From 50 parts by mass of 0 μm silica filler, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic anhydride 40 parts by weight of a synthesized polyimide resin having a weight average molecular weight of 50,000, 5 parts by weight of a phenol novolak resin (hydroxyl equivalent: 104, softening point: 80 ° C.) as a curing agent, and 1 part of Curezol 2PZ as an accelerator are bonded together in an organic solvent. Agent composition 2 was obtained.

Examples and comparative examples were evaluated as follows.
<Measurement of average molecular weight of adhesive>
From the pressure-sensitive adhesive film prepared using the pressure-sensitive adhesive composition, only the pressure-sensitive adhesive was scraped off and measured by a gel-permeation chromatography method (GPC) using a polystyrene conversion value using a standard polystyrene calibration curve. The following conditions were used for the measurement.
GPC device: HLC-8120GPC manufactured by Tosoh Corporation
Column: TSK gel SuperH5000, flow rate: 0.6 ml / min
Concentration: 0.3% by mass, injection amount: 20 μl
Column temperature: 40 ° C., eluent: tetrahydrofuran.
<Measurement of weight loss>
The pressure-sensitive adhesive layers of the dicing die bonding films according to Examples 1 to 6 and Comparative Examples 1 to 3 were irradiated with 200 mJ / cm ² of ultraviolet rays using an air-cooled high-pressure mercury lamp (80 W / cm, irradiation distance 10 cm). For Example 1 and Examples 2 to 6 and Comparative Examples 1 to 3 after UV irradiation, differential thermal analysis (TG-DTA) by thermogravimetry was performed, and the temperature in the measurement container was changed from room temperature to 300 ° C. The weight loss was measured and the weight loss at 220 ° C and 260 ° C was determined. The sample amount was about 10 mg, and the temperature was changed at a rate of 10 ° C./min. The results are shown in Table 1.
<Reflow resistance>
The adhesive layer of the dicing die bonding film according to the example and the comparative example is pasted on the back surface of the silicon wafer having a thickness of 200 μm, and dicing to 7.5 mm × 7.5 mm to stick the chip with the adhesive layer to the adhesive. After peeling from the layer and picking up, XPS (X-ray photoelectron spectroscopic analysis) selects 20 chips with an increase in carbon derived from transfer contaminants of the adhesive of 5 Atomic% or more compared to the blank, and glass. The substrate was mounted on an epoxy substrate under conditions of 180 ° C., 10 N, and 5 seconds. Furthermore, it molded with the sealing material (made by Kyocera Chemical Co., Ltd.), and produced the reflow sample. The sealed sample is treated with a constant temperature and humidity layer of 85 ° C./85% RH for 168 hours and then heated at 220 ° C. for 60 seconds for eutectic solder process or at 260 ° C. for 60 seconds for lead free solder process. Observation was made with an ultrasonic imaging device (SAT) manufactured by Hitachi Construction Machinery Co., Ltd., and the presence or absence of package cracks was examined. Table 1 shows the number of packages in which package cracks were observed for all 20 packages.

In the comparative example, cracks were observed in most packages because the weight loss at 220 ° C. and 260 ° C. both exceeded 1.5%. On the other hand, in Examples 1 to 6, since the weight loss at 220 ° C. and 260 ° C. was 1.5% or less, no crack was observed in all the packages.

11: Base film 12: Adhesive layer 13: Adhesive layer 14: Adhesive film 15: Semiconductor wafer processing tape 20: Ring frame 21: Stage 22: Adsorption stage 23: Push-up member

Claims

A pressure-sensitive adhesive film comprising a base film and a pressure-sensitive adhesive layer provided on the base film and used for processing a semiconductor wafer, the weight of the pressure-sensitive adhesive layer at a reflow temperature measured by differential thermal analysis A pressure-sensitive adhesive film having a reduction of 1.5% or less.
A pressure-sensitive adhesive film comprising a base film and a pressure-sensitive adhesive layer provided on the base film, and used for processing a semiconductor wafer, the weight of the pressure-sensitive adhesive layer at 260 ° C. measured by differential thermal analysis A pressure-sensitive adhesive film having a reduction of 1.5% or less.
A wafer processing tape having an adhesive film comprising a base film and an adhesive layer provided on the base film, and an adhesive layer provided on the adhesive layer, which is obtained by differential thermal analysis. A tape for processing a semiconductor wafer, wherein the weight loss of the pressure-sensitive adhesive layer at the measured reflow temperature is 1.5% or less.
A wafer processing tape having an adhesive film comprising a base film and an adhesive layer provided on the base film, and an adhesive layer provided on the adhesive layer, which is obtained by differential thermal analysis. A tape for processing a semiconductor wafer, wherein the weight loss of the pressure-sensitive adhesive layer measured at 260 ° C. is 1.5% or less.
The semiconductor wafer processing tape according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer has a weight average molecular weight of 1,000,000 or more.
The pressure-sensitive adhesive layer contains a photopolymerization initiator, and a thermal decomposition start temperature of the photopolymerization initiator is 260 ° C. or higher. Semiconductor wafer processing tape.