JP2006237465A - Die attaching film fitted with dicing-sheet function, semiconductor device manufacturing method using same, and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicon-wafer regeneration method using a highly reliable die attaching film fitted with a dicing-sheet function capable of peeling a film-like bonding agent from the rear surface of a silicon wafer without damaging the wafer, when requiring the reuse of the silicon wafer due to the faultiness generated in the case of sticking, etc. <P>SOLUTION: The silicon-wafer regeneration method includes a process for irradiating with ultraviolet rays a die attaching film fitted with a dicing-sheet function whereon a silicon wafer 5 is stuck, and includes a process for peeling thereafter the silicon wafer 5 from the die attaching film fitted with a dicing-sheet function whereon the silicon wafer 5 is stuck. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a die attach film with a dicing sheet function, a method for manufacturing a semiconductor device using the die attach film, and a semiconductor device.

In response to the recent increase in functionality of electronic devices and expansion to mobile applications, there is an increasing demand for higher density and higher integration of semiconductor devices, and IC packages are increasing in capacity and density.
As a manufacturing method of these semiconductor devices, an adhesive sheet is attached to a semiconductor wafer made of silicon, gallium, arsenic, etc., and after cutting and separating into individual semiconductor elements by dicing, expanding, picking up individual chips, Next, the semiconductor chip is transferred to an assembly process of a semiconductor device in which a semiconductor chip is die-bonded to a metal lead frame, a tape substrate, or an organic hard substrate.

  The picked-up semiconductor chip is bonded to a lead frame or a substrate through a die attach material such as a film adhesive layer in a die bonding process, and a semiconductor device is manufactured (Patent Documents 1 and 2).

JP 2002-353252 A JP 2002-294177 A

Instead of paste adhesives, film adhesives are becoming mainstream for this die bonding material. In this method, a film-like adhesive previously pasted on the back surface of a silicon wafer is cut into individual semiconductor elements by dicing together with the film-like adhesive and die-mounted on a substrate or chip. It is possible to shorten the process compared to the process of applying the paste adhesive on the substrate for each individual semiconductor element, and to improve the uniformity of the adhesive layer thickness after die mounting. Is possible.

Furthermore, a film adhesive having a dicing sheet function has been developed and put on the market as a new application of this film adhesive. This can further shorten the process by attaching a wafer adhesive to the dicing sheet and also attaching a film adhesive. Compared to the process of pasting only the film adhesive once on the back side of the wafer and then sticking it again to the dicing sheet, it is more effective for handling large-diameter wafers and thin wafers.

However, even if any film adhesive is used, a sticking failure may occur when it is attached to the back surface of the wafer. This is worried about wrinkles in the film-like adhesive, and particularly in large-diameter wafers, pressure non-uniformity at the time of sticking occurs, and there is a concern about the air layer being involved.

Unlike a dicing sheet, once the film adhesive is applied to the back side of the wafer, it is difficult to remove it, and if it is forcibly removed, the wafer is damaged. In addition, if it can be easily peeled off, there will be a problem due to peeling of the adhesive during assembly in the subsequent steps. Therefore, it is common to discard a wafer in which a defect has occurred due to application of a film adhesive. In particular, when such a problem occurs in a large-diameter wafer, the loss of semiconductor elements to be discarded becomes serious in terms of quantity and amount.

  The present invention has been made in view of the above circumstances, and its purpose is to form a film-like adhesive without damaging the wafer when it becomes necessary to reuse the silicon wafer due to a problem during sticking. Another object of the present invention is to provide a method for reclaiming a silicon wafer using a highly reliable die attach film function with a dicing sheet function to which a part of the silicon wafer is peeled from the back surface of the silicon wafer.

[1] It includes a step of irradiating a die attach film with a dicing sheet function to which a silicon wafer is attached, and then a step of peeling the silicon wafer from the die attach film with a dicing sheet function to which the silicon wafer is attached. A method for reclaiming a silicone wafer, characterized in that
The die attach film with a dicing sheet function is composed of a base film (I), an adhesive layer, a base film (II) and a film adhesive layer in this order, and the film adhesive layer is an acrylic film. A method for reclaiming a silicone wafer comprising an acid ester copolymer, a thermosetting resin, and a photocurable resin.
[2] The method for reclaiming a silicone wafer according to [1], wherein the interface on the film adhesive layer side of the base film (II) is subjected to a release treatment.
[3] The method for reclaiming a silicone wafer according to [1] or [2], wherein the acrylic ester copolymer has a glass transition temperature of −30 ° C. or more and 60 ° C. or less.
[4] The method for reclaiming a silicone wafer according to any one of [1] to [3], wherein the thermosetting resin is an epoxy resin.
[5] The method for reclaiming a silicone wafer according to any one of [1] to [4], wherein the photocurable resin is an acrylic resin.

The recycling method of the present invention includes a step of irradiating a die attach film with a dicing sheet function to which a silicon wafer is attached, and then peeling the silicone wafer from the die attach film with a dicing sheet function to which the silicon wafer is attached. A method for reclaiming a silicone wafer, comprising the step of:
The die attach film with a dicing sheet function is composed of a base film (I), an adhesive layer, a base film (II) and a film adhesive layer in this order, and the film adhesive layer is an acrylic film. A method for reclaiming a silicone wafer comprising an acid ester copolymer, a thermosetting resin and a photocurable resin.
The following is an example, and the present invention is not limited to the following. Hereinafter, each component of the die attach film with a dicing sheet function used in the present invention and a reproducing method using the same will be described in detail.

As the base film (I) used in the present invention, known materials may be used. For example, polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polybutylene. General thermoplastics such as terephthalate, polyurethane, ethylene vinyl acetate copolymer, ionomer, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid ester copolymer, polystyrene, vinyl polyisoprene, polycarbonate In addition to the film made of resin, a film made of a mixture of these, and a film obtained by laminating these can be used. Of these base film (I), 30 to 70 parts by weight (preferably 40 to 60 parts by weight) And a mixture of 70 to 30 parts by weight (preferably 60 to 40 parts by weight) of a copolymer composed of a polystyrene block and a vinyl isoprene block. Moreover, in order to raise adhesiveness with an adhesive layer, you may perform the corona treatment on the surface of these base materials. The thickness of the base film (I) is preferably 30 to 300 μm, particularly preferably 50 to 200 μm.

The pressure-sensitive adhesive layer used in the present invention is not particularly limited. For example, in addition to a polymer obtained by polymerizing acrylic acid, methacrylic acid and an ester monomer thereof, an unsaturated monomer copolymerizable with the monomer ( For example, a copolymer obtained by copolymerizing vinyl acetate, styrene, acrylonitrile, or the like) is used.
The adhesive layer of the present invention has a rosin resin, a terpene resin, a coumarone resin, a phenol resin, a styrene resin, an aliphatic petroleum resin, an aromatic petroleum resin, and an aliphatic aromatic copolymer to increase the cohesive force. A tackifier such as petroleum resin may be added.

  Furthermore, an antistatic agent can be added as a component of the above-mentioned pressure-sensitive adhesive layer. By adding an antistatic agent, static electricity generated at the time of expanding or picking up can be suppressed, so that the reliability of the chip is improved. Specific examples of the antistatic agent include anionic, cationic, nonionic, and amphoteric surfactants, carbon black, silver, nickel, antimony-doped tin oxide, tin-doped indium oxide. Such powder is used. The antistatic agent is preferably used in the pressure-sensitive adhesive in an amount of 0 to 30 parts by weight, particularly 0 to 20 parts by weight.

  The pressure-sensitive adhesive layer of the present invention has a glass transition temperature of −30 ° C. or higher so that the base film (I) and the base film (II) can be fixed, and can be easily attached to the wafer ring and can be easily removed. It is preferable that it is 60 degrees C or less. If the glass transition temperature exceeds 60 ° C., it becomes difficult to attach the wafer ring at 60 ° C. or less, and if it falls below −30 ° C., the adhesive force is too strong and it becomes difficult to remove the wafer ring.

  In the present invention, the thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably about 5 to 35 μm. If it is less than 5 μm, there is a problem that the adhesive force is not sufficient and chips are scattered during dicing, and if it is 35 μm or more, chipping or the like tends to occur during dicing.

  In order to produce the pressure-sensitive adhesive layer, the components constituting the pressure-sensitive adhesive layer are dissolved in an appropriate organic solvent as necessary, and an appropriate thickness is obtained according to a generally known method such as a comma coater, a gravure coater, a die coater, or a reverse coater. It can be obtained by coating on a substrate by coating or spraying, and drying by heat treatment or the like at 80 to 100 ° C. for about 30 seconds to 10 minutes.

As the base film (II) used in the present invention, a known film may be used as long as one surface is subjected to surface release treatment, and examples thereof include a polypropylene film, a polyethylene film, and a polyethylene terephthalate film. Examples of the mold release treatment include a process for coating the film surface with a mold release agent and a process for forming fine irregularities on the film surface. Examples of the release agent include silicone-based, alkyd-based, and fluorine-based agents. In particular, treatment with a silicone-based release agent is preferable because of excellent pickup properties after dicing.
As thickness of base film (II), 5-100 micrometers is preferable, and 10-60 micrometers is especially preferable. If the thickness is too thin, there is a problem that chips are scattered during dicing, and if it is too thick, there is a problem that pickup failure occurs.
In the present invention, a film-like adhesive layer is formed on the surface of the substrate film (II) that has been surface-released, and the surface that has not been surface-released is attached to the pressure-sensitive adhesive layer. The film (II) can be easily peeled from the interface between the film-like adhesive layers, and excellent pick-up properties are realized.

  The resin composition which comprises the film adhesive layer of this invention consists of an acrylate ester copolymer, a thermosetting resin, and a photocurable resin.

  The acrylate copolymer used for the film-like adhesive layer of the present invention is excellent in terms of improvement in adhesion and cohesion. Moreover, it is preferable that the glass transition temperature of an acrylate ester copolymer is -20-120 degreeC. Furthermore, -20-60 degreeC is more preferable, and -10-50 degreeC is especially preferable. If the glass transition temperature is too low, the adhesive strength of the film-like adhesive layer becomes strong, and pickup failure may occur or workability may be reduced. If the glass transition temperature is too high, chipping or cracking may occur, or the effect of improving low-temperature adhesion may be reduced.

Examples of the acrylic ester copolymer include a copolymer having at least one monomer component among acrylic acid, acrylic ester, methacrylic ester and acrylonitrile. Among these, an acrylate copolymer having a compound having an epoxy group, a hydroxyl group, a carboxyl group, a nitrile group, or the like as a functional group is preferable. Thereby, the adhesiveness to adherends, such as a semiconductor element, can be improved more.
Specific examples of the compound having a functional group include glycidyl methacrylate having a glycidyl ether group, hydroxy methacrylate having a hydroxyl group, carboxy methacrylate having a carboxyl group, and acrylonitrile having a nitrile group.

  The content of the compound having a functional group is not particularly limited, but is preferably 0.5 to 40% by weight, particularly preferably 5 to 30% by weight, based on the entire acrylate copolymer. If the content is too low, chipping or cracks may occur, or the effect of improving adhesion may be reduced. If the content is too high, the adhesive strength is too strong, and pickup failure may occur or the effect of improving workability may be reduced.

  The weight average molecular weight of the acrylate copolymer is not particularly limited, but is preferably 100,000 or more, particularly preferably 150,000 to 1,000,000. When the weight average molecular weight is within this range, the film forming property of the adhesive film for a semiconductor can be improved.

  Next, the thermosetting resin used for the film-like adhesive layer of the present invention includes, for example, bisphenol type epoxy resins such as bisphenol A epoxy resin and bisphenol F epoxy resin, novolak type epoxy resins such as novolac epoxy resin and cresol novolac epoxy resin. , Epoxy resins such as biphenyl type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, alkyl modified triphenolmethane type epoxy resin, triazine nucleus-containing epoxy resin, dicyclopentadiene modified phenol type epoxy resin, etc. In addition, phenol novolac resins, cresol novolac resins, bisphenol A novolac resins and other novolac phenol resins, resol phenol resins and other phenol resins, urea (urea) resins, Resins having a triazine ring such as Min resin, unsaturated polyester resins, bismaleimide resins, polyurethane resins, diallyl phthalate resins, silicone resins, resins having a benzoxazine ring, and also cyanate ester resin. These may be used alone or in combination.

  The thermosetting resin is preferably an epoxy resin, and particularly preferably a crystalline epoxy resin. Examples of such crystalline epoxy resins include those having a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, and a stilbene skeleton in the main chain and having a relatively low molecular weight. The reason why the crystalline epoxy resin is preferable is that it is a solid that is crystallized at room temperature, but rapidly melts into a low-viscosity liquid in a temperature range above the melting point. Thereby, the initial adhesion in the step of bonding the back surface of the silicon wafer to the adhesive layer portion of the die attach film with a dicing sheet function of the present invention can be further improved.

  The amount of the epoxy resin used in the film-like adhesive layer of the present invention is preferably 10 to 100 parts by weight, more preferably 30 to 70 parts by weight with respect to 100 parts by weight of the acrylic ester copolymer. If the amount is too large, chipping or cracking may occur, or the effect of improving adhesion may be reduced. If the blending amount is too low, the adhesive strength is too strong and pick-up failure may occur, or the effect of improving workability may be reduced.

As photocurable resin used for the film adhesive layer of this invention, acrylic resin is preferable. Examples include acrylic acid or methacrylic acid ester monomers. Among them, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, glycerol diacrylate, glycerol dimethacrylate, 1,10-decanediol diacrylate, dimethacrylate Bifunctional acrylates such as acid 1,10-decanediol, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate And other polyfunctional acrylates. Of these, alkyl esters are preferred, and acrylic acid and methacrylic acid alkyl esters having 1 to 15 carbon atoms in the ester moiety are particularly preferred.

  The content of the component unit derived from acrylic acid or methacrylic acid ester which is a photocurable resin used in the present invention is usually 10 to 100 parts by weight, preferably 20 to 100 parts by weight of acrylic acid ester copolymer. ~ 50 parts by weight. If it is less than the lower limit, the adhesive strength is poor, and if it exceeds the upper limit, tackiness is increased and workability is deteriorated.

  In addition, by introducing acrylic acid or methacrylic acid ester of a photocurable resin having a hydroxyl group such as a hydroxy group in the molecule, the adhesion to the adherend and the properties of the adhesive can be easily controlled. .

  Further, by mixing a polymerization initiator in the photocurable resin, it is possible to accelerate the polymerization of the photocurable resin by applying ultraviolet rays, heat or the like.

  Specific examples of such a polymerization initiator include benzophenone, acetophenone, benzoin, benzoin isobutyl ether, methyl benzoin benzoate, benzoin benzoic acid, benzoin methyl ether, benzylfinyl sulfide, benzyl, dibenzyl, and diacetyl. .

  Content of a polymerization initiator is 0.1-30 weight part with respect to 100 weight part of photocurable resins, Preferably it is 1-10 weight part. If it is less than 1 part by weight, the effect of the photoinitiator is weak, and if it exceeds 10 parts by weight, the reactivity becomes high and the storage stability becomes poor.

The film adhesive layer of this invention can contain a hardening | curing agent as needed.
Examples of the curing agent include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA), diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylsulfone. In addition to aromatic polyamines such as (DDS), amine-based curing agents such as polyamine compounds including dicyandiamide (DICY) and organic acid dihydralazide, and fats such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA) Acid anhydride curing agents such as aromatic acid anhydrides such as cyclic acid anhydride (liquid acid anhydride), trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenone tetracarboxylic acid (BTDA) , Phenolic tree Phenolic curing agent and the like.
Among these, a phenolic curing agent is preferable, and specifically, bis (4-hydroxy-3,5-dimethylphenyl) methane (common name: tetramethylbisphenol F), 4,4′-sulfonyldiphenol, 4,4′- Isopropylidene diphenol (commonly called bisphenol A), bis (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane and bis (4-hydroxy) Bisphenols such as three mixtures of phenyl) methane, bis (2-hydroxyphenyl) methane, and (2-hydroxyphenyl) (4-hydroxyphenyl) methane (for example, bisphenol FD manufactured by Honshu Chemical Industry Co., Ltd.) , 1,2-benzenediol, 1,3-benzenediol Dihydroxybenzenes such as 1,4-benzenediol, trihydroxybenzenes such as 1,2,4-benzenetriol, various isomers of dihydroxynaphthalene such as 1,6-dihydroxynaphthalene, 2,2′-biphenol, Examples of the compound include various isomers of biphenols such as 4,4′-biphenol.

  Although the compounding quantity of the said hardening | curing agent is not specifically limited, 1-90 weight part is preferable with respect to 100 weight part of said acrylate ester copolymers, and 3-60 weight part is especially preferable. If the blending amount is too low, the effect of improving the heat resistance may be lowered, and if the blending amount is too high, the storage stability may be lowered.

  The film adhesive layer of the present invention may contain imidazoles as a curing accelerator. Specifically, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2- Methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-benzylimidazole, 1-cyanoethyl-2-ethyl-4-ethylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazo Lithium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 1-cyanoethyl-2 -Phenylimidazolium trimellitate, 2 4-Diamino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4-methylimidazolyl- (1')] -Ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2-phenylimidazole isocyanuric adduct, 2-methylimidazole isocyanuric adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-benzyl-2- Phenylimidazole hydrobromide, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, 2,4-diamino-6-vinyl-s-triazine, 2,4-diamino-6-vinyl-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-s -Compounds such as -triazine, 2,4-diamino-6-methacryloyloxyethyl-s-triazine isocyanuric acid adduct.

  Although the compounding quantity of the said hardening accelerator is not specifically limited, 0.01-30 weight part is preferable with respect to 100 weight part of said acrylate ester copolymers, and 0.5-10 weight part is especially preferable. If the blending amount is too low, the curability may be insufficient, and if it is too high, the storage stability may decrease.

  The film adhesive layer of the present invention can further contain a coupling agent as required. Thereby, the adhesiveness between the resin and the adherend and between the resin and the silica interface can be improved.

  Examples of coupling agents include silane-based, titanium-based, and aluminum-based, among which silane-based coupling agents are preferable. As the coupling agent, for example, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyl Methyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (Aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ Aminopropyltrimethoxysilane, .gamma.-chloropropyl trimethoxy silane, .gamma.-mercaptopropyltrimethoxysilane, 3-isocyanate propyl triethoxysilane, 3-acryloxypropyl and propyl trimethoxy silane.

  Although the compounding quantity of the said coupling agent is not specifically limited, 0.01-10 weight part is preferable with respect to 100 weight part of said acrylate ester copolymers, and 0.1-10 weight part is especially preferable. If the blending amount is too low, the adhesion effect may be insufficient, and if it is too high, it may cause outgassing or voids.

  You may mix | blend a filler with the film adhesive layer of this invention as needed. The average particle size of the filler is preferably 0.1 to 25 μm. When the average particle size is less than 0.1 μm, the effect of filler addition is small, and when it exceeds 25 μm, the adhesive strength as a film may be reduced.

  As a filler used for the film adhesive layer of the present invention, silver, titanium oxide, silica, mica and the like are preferable. The blending amount of the filler is preferably 0.1% to 30% by weight, and if it exceeds 30%, the film becomes brittle and the adhesiveness is lowered.

  The film adhesive layer of the present invention is affixed to a wafer at a temperature of 15 ° C. or more and 60 ° C. or less. By enabling bonding under mild conditions, warping and cracking after wafer bonding can be suppressed.

  As a method for producing a die attach film with a dicing sheet function of the present invention, first, a resin composition constituting a film-like adhesive layer is appropriately formed on the surface of the base film (II) that has been subjected to a release treatment. It is made into a solution with a simple organic solvent, applied and dried according to generally known methods such as a comma coater, a die coater, and a gravure coater to form a film-like adhesive layer, and a protective sheet is laminated thereon. Alternatively, on the heat-resistant protective sheet, the resin composition constituting the film-like adhesive layer is made into a solution with an appropriate organic solvent as necessary, and is applied according to generally known methods such as a comma coater, die coater, and gravure coater. And dried to form an adhesive layer, on which the base film (II) is laminated. The three-layer structure of the base film (II) and the film-like adhesive layer obtained in a circular shape by half-cutting the base film (II) and the adhesive layer obtained here, and an uncut protective film A sheet is obtained. Since the half-cut circle is larger than the outer diameter of the portion to which the wafer is to be attached and smaller than the inner diameter of the portion to which the wafer ring is to be attached, it can be used for semiconductor device fabrication work without contaminating the wafer ring.

  In addition, the components constituting the pressure-sensitive adhesive layer are made into a solution with an appropriate organic solvent as necessary, and a base material is applied or spread to an appropriate thickness according to a generally known method such as a comma coater, gravure coater, die coater, reverse coater, etc. A two-layer structure sheet coated on the film (I) and coated with the pressure-sensitive adhesive layer on the base film (I) is obtained. Alternatively, on the heat-resistant protective sheet, the resin composition constituting the pressure-sensitive adhesive layer is dissolved in an appropriate organic solvent as necessary, and is applied according to a generally known method such as a comma coater, a die coater, a gravure coater, By drying, a pressure-sensitive adhesive layer is formed, and the base film (I) is laminated thereon, whereby a two-layer structure sheet in which the pressure-sensitive adhesive layer is coated on the base film (I) is obtained.

  By laminating the above-mentioned half-cut three-layer structure sheet on the two-layer structure sheet of the base film (I) coated with the above-mentioned pressure-sensitive adhesive layer, the base film (I), the pressure-sensitive adhesive layer, and the base material A die attach film in which the film (II) and the film adhesive layer are formed in this order can be obtained.

  As one aspect of the present invention, the outer diameter of the base film (II) and the adhesive layer is larger than the outer diameter of the portion to be attached to the wafer and smaller than the inner diameter of the portion to be attached to the wafer ring. There is something. The outer diameter of the film-like adhesive layer on the base film (II) is larger than the part to be attached to the wafer, so that the film-like adhesive layer is attached to the entire surface of the wafer and is smaller than the inner diameter of the part to be attached to the wafer ring. Thus, the wafer ring and the film-like adhesive layer can be prevented from sticking, and the wafer ring can be attached to the pressure-sensitive adhesive on the base film (I). When the wafer ring and the film-like adhesive layer come into contact with each other, there arises a problem that the film-like adhesive layer adheres to the wafer ring and the wafer ring is contaminated.

The die attach film with a dicing sheet function used in the present invention is usually used as follows.
First, the adhesive layer of the die attach film with a dicing sheet function of the present invention is pasted on the back surface of the silicon wafer under a mild condition of room temperature or 60 ° C., and then the wafer ring is pasted on the adhesive layer and then the die attach film A silicon wafer with a die is fixed on a dicing apparatus via a light-transmitting substrate, and the above silicon wafer with a die attach film is cut into individual pieces by using a cutting means such as a dicing saw. A semiconductor chip is obtained.

Subsequently, ultraviolet light (center wavelength = about 365 nm) is irradiated onto the light-transmitting substrate surface of the die attach film attached to the semiconductor chip obtained as described above. Usually, the illuminance is set to 20 to 500 mJ / cm ² and the irradiation time is set to a range of 5 to 600 seconds. Various conditions can be set according to the case of the above-mentioned ultraviolet irradiation.
Next, the die attach film is peeled off at the interface between the light-transmitting base material and the adhesive layer while the die attach film remains fixed on the back surface of the semiconductor chip.
At this time, the adhesive force also decreases at the adhesive interface with the back surface of the silicon wafer. However, the surface of the base film (II) that constitutes the die attach film with the dicing sheet function is subjected to a mold release treatment to transmit light. It is possible to give priority to peeling at the interface between the adhesive substrate and the adhesive layer, and it is possible to obtain a semiconductor chip in which the die attach film remains fixed on the back surface.

In this way, die bonding is performed by heating and pressure-bonding the semiconductor chip to which the film-like adhesive layer of the die attach film is fixed to a metal lead frame or substrate through the film-like adhesive layer as it is. Can do. The heating and pressure bonding conditions are usually a heating temperature of 100 to 300 ° C., a pressure bonding time of 1 to 10 seconds, preferably a heating of 100 to 200 ° C. and a pressure bonding time of 1 to 5 seconds. Subsequently, by heating, the epoxy resin in the die attach film is cured, and a semiconductor device in which the semiconductor chip and the lead frame, the substrate, etc. are firmly bonded can be obtained. The heating temperature in this case is usually about 100 to 300 ° C, preferably about 150 to 250 ° C, and the heating time is usually 1 to 240 minutes, preferably 10 to 60 minutes.
The finally cured die attach film has high heat resistance, and because of the acrylic rubber resin component, the cured product has low brittleness, excellent shear strength, high impact resistance, and heat resistance.

  The above is the normal usage method of the die attach film with a dicing sheet function used for this invention. However, in actual work, a defect may occur when a silicon wafer is attached. According to the present invention, even in such a case, the wafer can be peeled off from the film adhesive layer without wasting it. Specifically, the defective adhesion of the silicon wafer includes wrinkles in the film adhesive, and in particular, in a large-diameter wafer, pressure non-uniformity at the time of application occurs, so that an air layer is involved.

As a method for reclaiming a silicon wafer of the present invention, first, the adhesive layer of the die attach film with a dicing sheet function of the present invention is attached to the back surface of the silicon wafer under room temperature or a mild condition of 60 ° C. or less. When defects such as wrinkles or entangled voids occur between the adhesive layer and the back surface of the silicon wafer at the time of application, the light-transmitting substrate surface of the die attach film is irradiated with ultraviolet rays (center wavelength = about 365 nm). Usually, the illuminance is set to 20 to 500 mJ / cm ² and the irradiation time is set to a range of 5 to 600 seconds. Various conditions can be set according to the case of the above-mentioned ultraviolet irradiation. The adhesive layer and the die attach film with a dicing function are peeled off from the back surface of the silicon wafer without damaging the silicon wafer because the adhesiveness at the interface between the film adhesive cured with ultraviolet rays and the silicon wafer becomes low. Can do.

  As described above, when the silicon wafer is appropriately attached to the adhesive layer of the die attach film with dicing sheet function used in the present invention, the silicon wafer can be attached to the substrate without any problem, while the die attach with dicing sheet function is possible. When a silicon wafer is mistakenly attached to the adhesive layer of the film, the film-like adhesive layer attached to the silicon wafer can be easily peeled off by irradiating ultraviolet rays before cutting into individual dies with a dicing saw. Can do.

Example 1
[1] Base film (I) and pressure-sensitive adhesive layer As a base film (I), Cleartech CT-H717 (Kuraray) consisting of 60 parts by weight of Hibra and 40 parts by weight of polypropylene is used to form a 100 μm thick film with an extruder. Formed and corona treated. Next, a copolymer having a weight average molecular weight of 500,000 obtained by copolymerizing 50 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of butyl acrylate, 37 parts by weight of vinyl acetate, and 3 parts by weight of 2-hydroxyethyl methacrylate. Was applied to a polyester film having a thickness of 38 μm, and the thickness after drying was 10 μm, followed by drying at 80 ° C. for 5 minutes to obtain a pressure-sensitive adhesive layer. Thereafter, the pressure-sensitive adhesive layer was laminated on the corona-treated surface of the base film (I) to obtain the base film (I) and the pressure-sensitive adhesive layer.

[2] Film adhesive layer component Film adhesive component A: Acrylic acid ester copolymer (glycidyl group-containing acrylic acid ester copolymer, manufactured by Nagase ChemteX Corporation, SG-80H, Tg: 15 ° C, 100 parts by weight of a weight average molecular weight: 350,000), 32 parts by weight of a crystalline cresol novolac epoxy resin (EOCN-1020-80, manufactured by Nippon Kayaku Co., Ltd.) as a thermosetting resin, and an epoxy resin (NC6000, Nippon Kayaku Co., Ltd.) 48 parts by weight, phenol curing agent (MEH7500, Meiwa Kasei Co., Ltd.) 39 parts by weight, photo-curing resin (TMP, manufactured by Kyoeisha Chemical Co., Ltd.) 50 parts by weight, photoinitiator ( IG651, Ciba Specialty Chemicals Co., Ltd.) 5 parts by weight,
As a coupling agent, 0.2 part by weight of γ-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in methyl ethyl ketone (MEK) to obtain a resin varnish having a resin solid content of 40%. .

[3] Film adhesive layer and substrate film (II)
Using a comma coater, the above-mentioned resin varnish was applied to the silicone release surface of a polyethylene terephthalate film (Oji Paper Co., Ltd., RL-07, thickness 38 μm) as the base film (II), It dried for 10 minutes and obtained the film adhesive layer with base film (II).

[4] Die attach film with dicing sheet function Dicing sheet function with dicing sheet function A protective film is pasted on the film-like adhesive layer with the base film (II) described above, and the base film (II) and the film-like adhesive layer are half-cut. The base film (I), the pressure-sensitive adhesive layer, the base film (II) and the film-like adhesive layer are obtained by attaching the adhesive film on the above-mentioned base film (I) and peeling off the protective film. A die attach film with a dicing sheet function constituted in this order was obtained.

[5] Semiconductor device using a die attach film with a dicing function The obtained die attach film with a dicing function was attached to the back surface of a 6-inch 550 μm wafer at 60 ° C. to obtain a wafer with a die attach film with a dicing function. The die attach film with the dicing function is peeled off from the silicon wafer after irradiating with 250 mJ / cm 2 of ultraviolet rays (center wavelength = about 365 nm) as an integrated dose from the back surface of the base film (I) of the wafer with the die attach film with the dicing function. It was. Then, a new die attach film with a dicing function was attached to the back surface of the silicon wafer from which the die attach film with a dicing function was peeled off at 60 ° C. to obtain a wafer with a die attach film with a dicing function. After that, the wafer with a die attach film with a dicing function is diced (cut) into a size of a semiconductor element of 5 mm × 5 mm square at a spindle rotation speed of 30,000 rpm and a cutting speed of 50 mm / sec using a dicing saw, and then diced. The dicing sheet with sheet function was pushed up from the back surface and peeled off between the base film (II) and the film adhesive layer.

(Example 2)
Film adhesive component B: A die attach film with a dicing sheet function and a semiconductor chip using the same are obtained in the same manner as in Example 1 except that the composition of the resin varnish of the film adhesive layer component is as follows. It was.
100 parts by weight of acrylic ester copolymer (glycidyl group-containing acrylic ester copolymer, manufactured by Nagase ChemteX Corp., SG-80H, Tg: 15 ° C., weight average molecular weight: 350,000), and thermosetting As resin, crystalline cresol novolac epoxy resin (EOCN-1020-80, manufactured by Nippon Kayaku Co., Ltd.) 10 parts by weight, epoxy resin (NC6000, manufactured by Nippon Kayaku Co., Ltd.) 20 parts by weight, phenol curing agent ( MEH7500, Meiwa Kasei Co., Ltd.) 15 parts by weight, photo-curing resin (TMP, manufactured by Kyoeisha Chemical Co., Ltd.) 40 parts by weight, photoinitiator (IG651, manufactured by Ciba Specialty Chemicals Co., Ltd.), 4 parts by weight, coupling 0.1 part by weight of γ-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) as an agent.

(Example 3)
A die attach film with a dicing sheet function and a semiconductor chip using the same were obtained in the same manner as in Example 1 except that a polyethylene terephthalate film that was not subjected to release treatment was used as the base film (II).

(Comparative Example 1)
A die attach film with a dicing sheet function and a semiconductor chip using the same were obtained in the same manner as in Example 1 except that the composition of the resin varnish of the film adhesive layer component was as follows.
Film adhesive component C: Acrylic acid ester copolymer (glycidyl group-containing acrylic acid ester copolymer, manufactured by Nagase ChemteX Corporation, SG-80H, Tg: 15 ° C., weight average molecular weight: 350,000) 100 Parts by weight, 32 parts by weight of crystalline cresol novolac epoxy resin (EOCN-1020-80, manufactured by Nippon Kayaku Co., Ltd.) as a thermosetting resin, and epoxy resin (NC6000, manufactured by Nippon Kayaku Co., Ltd.) 48 Parts by weight, 39 parts by weight of a phenol curing agent (MEH7500, manufactured by Meiwa Kasei Co., Ltd.), 0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) as a coupling agent, Was used.

(Comparative Example 2)
Film adhesive component D: A die attach film with a dicing sheet function and a semiconductor chip using the same are obtained in the same manner as in Example 1 except that the resin varnish of the film adhesive layer component is mixed as follows. It was.
100 parts by weight of an acrylic ester copolymer (glycidyl group-containing acrylic ester copolymer, manufactured by Nagase ChemteX Corp., SG-80H, Tg: 15 ° C., weight average molecular weight: 350,000), and a coupling agent And 0.2 part by weight of γ-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) was used.

  The following evaluation was performed regarding the die attach film with a dicing sheet function obtained in each of the examples and comparative examples, and the semiconductor chip using the same. The evaluation items are shown together with the contents. The obtained results are shown in Tables 1 and 2.

(1) Wafer pick-up property under normal wafer attachment It was evaluated whether a semiconductor chip with a die attach film could be picked up from a light-transmitting substrate (pick-up) by irradiating with ultraviolet light after dicing the semiconductor wafer.
○: Almost all chips can be picked up △: 50-90% of diced chips can be picked up ×: Pick-up is 50% or less

(2) Wafer regeneration state at the time of wafer sticking failure ○: It was possible to peel off cleanly.
Δ: Although it was able to be peeled off, an adhesive residue was present on the back surface of the silicon wafer.
×: Cannot be peeled off, and the silicon wafer was damaged.

  As is apparent from Table 2, Examples 1 and 2 were excellent in peelability after ultraviolet irradiation and excellent in pick-up properties.

The method for reclaiming a silicon wafer according to the present invention greatly contributes to an improvement in yield at the time of assembling semiconductor elements.

FIG. 1 shows a sectional view of a die attach film with a dicing sheet function used in the present invention.

Explanation of symbols

1 Base film (I)
2 Adhesive layer 3 Base film (II)
4 film adhesive layer 5 silicon wafer 6 wafer ring

Claims (5)

It includes a step of irradiating a die attach film with a dicing sheet function to which a silicon wafer is attached, and a step of peeling the silicone wafer from the die attach film with a dicing sheet function to which the silicon wafer is attached. A method for reclaiming a silicone wafer,
The die attach film with a dicing sheet function is composed of a base film (I), an adhesive layer, a base film (II) and a film adhesive layer in this order, and the film adhesive layer is an acrylic film. A method for reclaiming a silicone wafer comprising an acid ester copolymer, a thermosetting resin, and a photocurable resin.   The method for reclaiming a silicone wafer according to claim 1, wherein the interface on the film adhesive layer side of the base film (II) is subjected to a release treatment.   The method for reclaiming a silicone wafer according to claim 1 or 2, wherein the acrylic ester copolymer has a glass transition temperature of -30 ° C to 60 ° C.   The method for reclaiming a silicone wafer according to any one of claims 1 to 3, wherein the thermosetting resin is an epoxy resin.   The method for reclaiming a silicone wafer according to claim 1, wherein the photocurable resin is an acrylic resin.

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