JP2010219293A - Tape for processing wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tape for processing a wafer capable of suppressing the occurrence of a double die error which causes an adjacent chip to be lifted together in a pickup process. <P>SOLUTION: The tape 10 for processing the wafer includes an adhesive film 12 comprising a base material film 12a and an adhesive layer 12b, and an adhesive layer 13. When the thickness of the adhesive layer 13 is defined as t(ad), a storage modulus at 80°C is defined as G'(80ad), tanδ is defined as tanδ(80ad), the thickness of the adhesive film 12 is defined as t(film), and tanδ at 80°C is defined as tanδ(80film), a value A indicated by an equation (1) is ≥0.043. When the adhesive layer 13 receives a push-in force by a dicing blade 21, the adhesive layer 13 is not easily deformed and the projection of the adhesive layer 13 from a semiconductor chip 2 is reduced. Thus, the adhesive layer 13 is not fused again. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wafer processing tape used in both a dicing step of cutting a semiconductor wafer into semiconductor elements (chips) and a die bonding step of bonding the cut chips to a lead frame or another chip.

  In the manufacturing process of a semiconductor device, a step of cutting (dicing) a semiconductor wafer into chips, a step of picking up a cut semiconductor element (chip), and die bonding for bonding the picked-up chip to a lead frame, a package substrate, etc. A (mount) process is performed.

In recent years, a dicing die-bonding sheet in which a pressure-sensitive adhesive layer and an adhesive layer are formed in this order on a base film is known as a wafer processing tape used in the manufacturing process of the semiconductor device (for example, a patent) Reference 1).
The adhesive layer used in such a dicing die bond sheet contains a lot of low molecular weight substances such as epoxy resins, and is softer and tends to be inferior in cutting ability than an adhesive layer used in general dicing tape. There is. Therefore, during dicing, there is a lot of whisker-like cutting waste and adhesive layer residue (burrs) on the semiconductor wafer, which tends to cause pick-up failure in the pick-up process after dicing, and in the assembly process of semiconductor devices such as I C However, there is a problem that defective bonding of the chip tends to occur or defective products such as I C are generated.
Therefore, as a wafer processing tape that solves such problems, a semiconductor processing tape in which an intermediate resin layer, an adhesive layer, and an adhesive layer are laminated in this order on a base film, A semiconductor processing tape is known in which the storage elastic modulus at 80 ° C. is larger than the storage elastic modulus at 80 ° C. of the pressure-sensitive adhesive layer (see, for example, Patent Document 2).

JP 2005-303275 A JP 2006-49509 A

However, in the wafer processing tape described in Patent Document 2, melting of the adhesive layer and the adhesive layer during dicing depends on the thickness of the adhesive layer and the adhesive layer and the elastic modulus of the adhesive layer and the adhesive layer. As a result, cutting residue (burrs) occurs in the adhesive layer, pressure-sensitive adhesive layer, etc., and adjacent chips (semiconductor chips with an adhesive layer separated into individual pieces) are picked up at the time of pickup due to the influence of the cutting residue. There was a problem that an error (double die error) occurred.
Accordingly, an object of the present invention is to provide a wafer processing tape that can suppress the occurrence of a double die error in which adjacent chips are lifted together in a pickup process.

  The present inventors use a tape for wafer processing having 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. When manufacturing a semiconductor device, if the adhesive layer is not easily deformed (elastically deformed) when it receives a force pushed by a dicing blade, the occurrence of a double die error in which the adjacent chips are lifted together in the pickup process is suppressed. I found out that I can do it. The reason is considered that if the adhesive layer is difficult to be deformed, the adhesive layer will not protrude from the semiconductor chip, and the protruding adhesive layer will not be re-fused. The present invention has been made based on the above-described findings.

式（1）で表される値Ａは、粘着フィルムと接着剤層を含むウエハ加工用テープ全体における、接着剤層の変形（弾性変形）のしにくさを表すパラメータである。
式（1）で表される値Aが0.043以上であるので、ダイシングブレードにより押し込まれる力で接着剤層が変形（弾性変形）しにくくなり、接着剤層の半導体チップからのはみ出しが少なくなる。これにより、接着剤層が再融着しない。従って、ピックアップ工程で隣接チップが一緒に持ち上がるダブルダイエラーの発生を抑制することができる。 A wafer processing tape according to the present invention includes a pressure-sensitive adhesive film comprising a base film and a pressure-sensitive adhesive layer provided on the base film, and a wafer processing having an adhesive layer provided on the pressure-sensitive adhesive layer. The adhesive layer has a thickness of t (ad) [um], the adhesive layer has a storage elastic modulus at 80 ° C. of G ′ (80ad) [MPa], and the adhesive layer has an adhesive layer of 80 ° C. When tan δ is tan δ (80ad), the thickness of the adhesive film is t (film) [um], and tan δ of the adhesive film at 80 ° C. is tan δ (80 film), the value A represented by the formula (1) is 0.043. It is the above.

The value A represented by the formula (1) is a parameter representing the difficulty of deformation (elastic deformation) of the adhesive layer in the entire wafer processing tape including the adhesive film and the adhesive layer.
Since the value A represented by the formula (1) is 0.043 or more, the adhesive layer is hardly deformed (elastically deformed) by the force pushed by the dicing blade, and the protrusion of the adhesive layer from the semiconductor chip is reduced. Thereby, an adhesive bond layer does not re-fuse. Therefore, it is possible to suppress the occurrence of a double die error in which adjacent chips are lifted together in the pickup process.

ADVANTAGE OF THE INVENTION According to this invention, the tape for wafer processing which can suppress generation | occurrence | production of the double die error which an adjacent chip | tip lifts together in a pick-up process is realizable.

It is sectional drawing which shows the tape for wafer processing which concerns on one Embodiment of this invention. It is the figure which bonded the semiconductor wafer on the tape for wafer processing. It is a figure for demonstrating a dicing process. It is a figure for demonstrating an expanding process. It is a figure for demonstrating a pick-up process. It is a schematic diagram for demonstrating the stress absorption capability of the adhesive bond layer and adhesive film in the tape for wafer processing which concerns on one Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a wafer processing tape 10 according to an embodiment. The wafer processing tape 10 includes an adhesive film 12 including a base film 12 a and an adhesive layer 12 b formed thereon, and an adhesive layer 13 laminated on the adhesive film 12. Thus, in the wafer processing tape 10, the base film 12a, the pressure-sensitive adhesive layer 12b, and the adhesive layer 13 are formed in this order.
The pressure-sensitive adhesive layer 12b may be composed of a single pressure-sensitive adhesive layer, or may be composed of a laminate of two or more pressure-sensitive adhesive layers. FIG. 1 shows a state where a release liner 11 is provided on the wafer processing tape 10 in order to protect the adhesive layer 13.

  The pressure-sensitive adhesive film 12 and the adhesive layer 13 may be cut (precut) into a predetermined shape in advance in accordance with the use process and the apparatus. The tape for wafer processing of the present invention includes a form cut for each semiconductor wafer and a form obtained by winding a plurality of long sheets formed on a roll.

The wafer processing tape 10 according to the present embodiment is characterized in that it has the following configuration.
(1) It has the adhesive film 12 which consists of the base film 12a and the adhesive layer 12b provided on the base film 12a, and the adhesive layer 13 provided on the adhesive layer 12b.
(2) The thickness of the adhesive layer 13 is t (ad) [um], the storage elastic modulus of the adhesive layer 13 at 80 ° C. is G ′ (80ad) [MPa], and the tan δ of the adhesive layer 13 at 80 ° C. is tan δ. (80ad), when the thickness of the adhesive film 12 is t (film) [um] and the tan δ of the adhesive film 12 at 80 ° C. is tan δ (80 film), the value A represented by the formula (1) is 0.043 or more. .

  The part other than G ′ (80ad) in the above formula (1) represents the ratio of the stress absorbing ability of the adhesive layer 13 to the stress absorbing ability of the entire wafer processing tape 10. A value A obtained by multiplying the ratio by the reciprocal of the storage elastic modulus G ′ (80ad) at 80 ° C. of the adhesive layer 13 is a parameter representing the difficulty of deformation (elastic deformation) of the adhesive layer 13. That is, the larger the value A, the smaller the deformation amount (elastic deformation amount) of the adhesive layer.

  In the above formula (1), the loss tangent tan δ (80ad) of the adhesive layer 13 and the loss tangent tan δ (80 film) of the pressure-sensitive adhesive film 12 at 80 ° C. indicate the stress absorption performance, and the larger the value, the higher the stress absorption. . This is the capacity per unit area, and by multiplying this value by the thickness, the overall stress absorption performance is obtained.

For example, as shown in FIG. 6, for wafer processing having a pressure-sensitive adhesive film 12 composed of a base film and a pressure-sensitive adhesive layer provided on the base film, and an adhesive layer 13 provided on the pressure-sensitive adhesive layer. In the tape 10, the thickness t (ad) of the adhesive layer 13 is 0.5 mm, its G ′ (80ad) is 10, its tan δ (80ad) is 0.9, and the thickness t (film) of the adhesive film 12 is 2 mm. tanδ (80 film) is set to 0.5.
In this case, the stress absorption capability a of the adhesive layer 13 is 0.5 × 0.9 = 0.45, the stress absorption capability b of the adhesive film 12 is 2.0 × 0.5 = 1.0, and the force c absorbed by the adhesive layer 13 is 100 × 0.45 / (0.45 +1.0) = 31, and the amount d of deformation of the adhesive layer 13 is 10 × 0.5 ÷ 31 = 0.16.
Here, 0.45 / (0.45 + 1.0) represents the ratio of the stress absorbing ability of the adhesive layer 13 to the stress absorbing ability of the wafer processing tape 10 as a whole. The larger the ratio, the more the adhesive layer becomes. The absorbing force c increases, and the amount d of deformation (elastic deformation) of the adhesive layer 13 decreases.
Thus, if the adhesive layer 13 is not easily deformed by the force pushed by the dicing blade 21 (FIG. 3), the protrusion of the adhesive layer 13 from the semiconductor chip 2 is reduced. Thereby, since the rebonding of the protruding adhesive layer is suppressed, it is possible to reduce the double die error in which the adjacent chips are lifted together in the pickup process.

When the value A represented by the above formula (1) is less than 0.043, the adhesive layer 13 is easily deformed (elastically deformed) by the force pushed by the dicing blade 21, and the adhesive layer 13 has a semiconductor chip. The amount of protrusion increases. As a result, the protruding adhesive layer is re-fused, and a double die error occurs in which the adjacent chips are lifted together in the pickup process.
Hereafter, each component of the tape 10 for wafer processing of this embodiment is demonstrated in detail.

(Adhesive layer)
The adhesive layer 13 is peeled off from the adhesive film 12 and attached to the semiconductor chip 2 when the semiconductor chip 2 is picked up after the semiconductor wafer 1 or the like is bonded and diced, and the semiconductor chip 2 is attached to the substrate or lead frame. It is used as an adhesive when being fixed to. Therefore, the adhesive layer 13 has a releasability that can be peeled off from the adhesive film 12 while remaining attached to the separated semiconductor chip 2 in the pick-up process. In order to bond and fix the semiconductor chip 2 to a substrate or a lead frame, it has sufficient bonding reliability.

  The adhesive layer 13 is obtained by forming a film of an adhesive in advance. For example, a known polyimide resin, polyamide resin, polyetherimide resin, polyamideimide resin, polyester resin, polyesterimide resin, phenoxy used for the adhesive is used. Resins, polysulfone resins, polyether sulfone resins, polyphenylene sulfide resins, polyether ketone resins, chlorinated polypropylene resins, acrylic resins, polyurethane resins, epoxy resins, polyacrylamide resins, melamine resins, and the like and mixtures thereof can be used.

  In view of good heat resistance after curing, it is particularly preferable to use an epoxy resin. Any epoxy resin that cures and exhibits an adhesive action may be used. As the epoxy resin, a polyfunctional epoxy resin may be added for the purpose of increasing the Tg (glass transition temperature), and examples of the polyfunctional epoxy resin include a phenol novolac type epoxy resin and a cresol novolac type epoxy resin. As the curing agent for the epoxy resin, those usually used as a curing agent for the epoxy resin can be used, and have at least two amines, polyamides, acid anhydrides, polysulfides, boron trifluoride and phenolic hydroxyl groups in one molecule. Examples of the compound include bisphenol A, bisphenol F, and bisphenol S. In particular, it is preferable to use phenol novolac resin, bisphenol novolac resin, or the like, which is a phenol resin, because of its excellent resistance to electric corrosion during moisture absorption. Moreover, it is preferable to use a curing accelerator together with the curing agent in terms of shortening the heat treatment time for curing. As a curing accelerator, bases such as various imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate are used. it can.

  Moreover, in order to strengthen the adhesive force with respect to the semiconductor chip 2 and the lead frame 20, it is desirable to add a silane coupling agent or a titanium coupling agent as an additive to the material or a mixture thereof. Further, a filler may be added for the purpose of improving heat resistance and adjusting fluidity. Such fillers include silica, alumina, antimony oxide and the like. As long as these fillers have a maximum particle size smaller than the thickness of the adhesive layer 13, products having different particle sizes can be blended at an arbitrary ratio.

  In order to increase tan δ (80ad) and decrease G ′ (80ad), it is preferable to increase low molecular weight components such as epoxy resin and phenol resin and decrease high molecular weight components such as acrylic resin. In addition, when a filler is blended, the amount of filler blended may be reduced, and the above may be reversed to lower tan δ.

  The thickness of the adhesive layer 13 is not particularly limited, but is usually preferably about 5 to 100 μm. The adhesive layer 13 may be laminated on the entire surface of the pressure-sensitive adhesive layer 12b of the pressure-sensitive adhesive film 12. However, the adhesive layer 13 that has been cut (pre-cut) into a shape corresponding to the semiconductor wafer 1 to be bonded in advance is adhered. You may laminate | stack on a part of agent layer 12b. When the adhesive layer 13 cut into a shape corresponding to the semiconductor wafer 1 is laminated, as shown in FIG. 2, the adhesive layer 13 is provided at a portion where the semiconductor wafer 1 is bonded, and a ring frame 20 for dicing is provided. There is no adhesive layer 13 in the portion where the adhesive film is bonded, and only the adhesive layer 12b of the adhesive film 12 exists. In general, since the adhesive layer 13 is difficult to peel off from the adherend, the ring frame 20 can be attached to the adhesive film 12 by using the pre-cut adhesive layer 13, and the ring is peeled off when the sheet is peeled after use. The effect that it is hard to produce the adhesive residue on a flame | frame is acquired.

(Adhesive film)
The adhesive film 12 has a sufficient adhesive force so that the semiconductor wafer 1 does not peel off when the semiconductor wafer 1 is diced, and can be easily peeled off from the adhesive layer 13 when the semiconductor chip 2 is picked up after dicing. It has such a low adhesive strength. In the present embodiment, as the adhesive film 12, as shown in FIG. 1, a substrate film 12a provided with an adhesive layer 12b is used.

  The base film 12a of the adhesive film 12 can be used without particular limitation as long as it is a conventionally known one. However, in the present embodiment, as the adhesive layer 12b, as described later, energy curable is used. Since a radiation curable material is used among these materials, a material having radiation transparency is used.

  For example, as a material of the base film 12a, polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer , Homopolymers or copolymers of α-olefins such as ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, ionomer or mixtures thereof, polyurethane, styrene-ethylene-butene copolymer or pentene Listed are thermoplastic elastomers such as copolymers, polyamide-polyol copolymers, and mixtures thereof. Moreover, the base film 12a may be a mixture of two or more materials selected from these groups, or may be a single layer or a multilayer. The thickness of the base film 12a is not particularly limited and may be set appropriately, but is preferably 50 to 200 μm.

  tanδ (80 film) is attributed to the structure of the resin used for the base film 12a. More specifically, the higher the molecular weight and the smaller the molecular weight between the entanglement points, the higher the tanδ film.

  In the present embodiment, the pressure-sensitive adhesive layer 12b is cured by irradiating the pressure-sensitive adhesive film 12 with radiation such as ultraviolet rays, and the pressure-sensitive adhesive layer 12b is easily peeled off from the pressure-sensitive adhesive layer 13. For the resin 12b, known chlorinated polypropylene resins, acrylic resins, polyester resins, polyurethane resins, epoxy resins, addition-reactive organopolysiloxane resins, silicon acrylate resins, ethylene-vinyl acetate copolymer used for adhesives Copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-acrylic acid copolymers, various elastomers such as polyisoprene, styrene / butadiene copolymers and hydrogenated products thereof, and mixtures thereof It is preferable to prepare a pressure-sensitive adhesive by appropriately blending a radiation polymerizable compoundVarious 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 5 to 30 μm.

  The radiation-polymerizable compound includes, for example, a low molecular weight compound having at least two photopolymerizable carbon-carbon double bonds in a molecule that can be three-dimensionally networked by light irradiation, or a photopolymerizable carbon-carbon double bond group. A polymer or oligomer having a substituent is used. 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. The urethane acrylate oligomer includes a polyol compound such as a polyester type or a polyether type, and a polyvalent isocyanate compound (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 12b may be a mixture of two or more selected from the above resins.

  The resin of the pressure-sensitive adhesive layer 12b is appropriately blended with an acrylic pressure-sensitive adhesive, a photopolymerization initiator, a curing agent, etc., in addition to a radiation-polymerizable compound that cures the pressure-sensitive adhesive layer 12b by irradiating the pressure-sensitive adhesive film 12 with radiation. Thus, the pressure-sensitive adhesive layer 12b 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 5 parts by mass with respect to 100 parts by mass of the acrylic copolymer.

(How to use wafer processing tape)
In the semiconductor device manufacturing process, the wafer processing tape 10 is used as follows. FIG. 2 shows a state in which the semiconductor wafer 1 and the ring frame 20 are bonded to the wafer processing tape 10. First, as shown in FIG. 2, the adhesive layer 12 b of the adhesive film 12 is attached to the ring frame 20, and the semiconductor wafer 1 is attached to the adhesive layer 13. There is no limitation on the order of these attachments, and the adhesive layer 12b of the adhesive film 12 may be attached to the ring frame 20 after the semiconductor wafer 1 is attached to the adhesive layer 13. Further, the adhesion of the adhesive film 12 to the ring frame 20 and the adhesion of the semiconductor wafer 1 to the adhesive layer 13 may be performed simultaneously.

  Then, a dicing process of the semiconductor wafer 1 is performed (FIG. 3), and then a process of irradiating the adhesive film 12 with energy rays, for example, ultraviolet rays. Specifically, since the semiconductor wafer 1 and the adhesive layer 13 are diced by the dicing blade 21, the wafer processing tape 10 is sucked and supported from the adhesive film 12 surface side by the suction stage 22. Then, the dicing blade 21 cuts the semiconductor wafer 1 and the adhesive layer 13 into units of two semiconductor chips, and then irradiates energy rays from the lower surface side of the adhesive film 12. By this energy ray irradiation, the pressure-sensitive adhesive layer 12b is cured to reduce its adhesive strength. In addition, it may replace with energy ray irradiation and may reduce the adhesive force of the adhesive layer 12b of the adhesive film 12 by external stimuli, such as a heating. When the pressure-sensitive adhesive layer 12b is formed by laminating two or more pressure-sensitive adhesive layers, one or all of the pressure-sensitive adhesive layers are cured by irradiation with energy rays, and one of the pressure-sensitive adhesive layers. Or you may reduce the adhesive force of all the layers.

  Thereafter, as shown in FIG. 4, an expanding process is performed in which the adhesive film 12 holding the diced semiconductor chip 2 and the adhesive layer 13 is stretched in the circumferential direction of the ring frame 20. Specifically, the hollow cylindrical push-up member 30 is raised from the lower surface side of the pressure-sensitive adhesive film 12 with respect to the pressure-sensitive adhesive film 12 in a state where the plurality of diced semiconductor chips 2 and the adhesive layer 13 are held. The film 12 is stretched in the circumferential direction of the ring frame 20. The expansion process widens the distance between the semiconductor chips 2 and improves the recognizability of the semiconductor chips 2 by a CCD camera or the like, and the re-adhesion between the semiconductor chips caused by the contact between the adjacent semiconductor chips 2 at the time of pickup. Can be prevented.

  After performing the expanding process, as shown in FIG. 5, the pick-up process which picks up the semiconductor chip 2 is implemented with the adhesive film 12 being expanded. Specifically, the semiconductor chip 2 is pushed up by the pins 31 from the lower surface side of the adhesive film 12 and the semiconductor chip 2 is separated from the upper surface side of the adhesive film 12 by adsorbing the semiconductor chip 2 by the adsorption jig 32. Is picked up together with the adhesive layer 13.

Then, after performing the pickup process, the die bonding process is performed. Specifically, the semiconductor chip 2 is bonded to a lead frame, a package substrate, or the like by the adhesive layer 13 picked up together with the semiconductor chip 2 in the pickup process.
Next, examples of the present invention will be described, but the present invention is not limited to these examples.
The adhesive films and adhesive films (1) to (4) having the adhesive layers (1) and (2) shown in Table 1 are cut into circles having a diameter of 370 mm and 320 mm, respectively, and the adhesive films (1) to (4) The pressure-sensitive adhesive layer was bonded to the adhesive layer of the adhesive film having any one of the adhesive layers (1) and (2). Finally, the PET film of the adhesive film was peeled from the adhesive layer, and each wafer processing tape of Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1 was obtained.

(Preparation of adhesive layer)
<Adhesive layer (1)>
YDCN-703 (trade name, manufactured by Tohto Kasei Co., Ltd., cresol novolac type epoxy resin, epoxy equivalent 210 g / eq, molecular weight 1200, softening point 80 ° C.) 55 parts by weight as an epoxy resin, Mirex XLC-LL (Mitsui Chemicals) as a phenol resin Product name, hydroxyl equivalent 175 g / eq, water absorption 1.8%, heating weight loss rate 4% at 350 ° C. 45 parts by weight, Z-6044 (Toray Dow Corning Co., Ltd.) as silane coupling agent Product name, 0.3 part by weight of 3-glycidoxypropylmethylmethoxysilane, S0-C2 (trade name of Admafine Co., Ltd., specific gravity 2.2 g / cm ³ , Mohs hardness 7, average particle as silica filler diameter 0.5 [mu] m, a specific surface area of 6.0 m ² / g) 30 parts by weight, Curezol 2PZ as a curing accelerator (Shikoku Chemicals Corporation Product name, 2-phenylimidazole) 0.4 part by weight, 275 parts by weight of SG-P3 (manufactured by Nagase ChemteX Corp., weight average molecular weight 850,000, glass transition temperature 10 ° C.) as an acrylic resin in an organic solvent To obtain an adhesive layer composition. This adhesive layer composition was coated on a release-treated polyethylene terephthalate (PET) film and dried to prepare an adhesive film having an adhesive layer (1) with a thickness of 20 μm. The loss tangent tan δ (80ad) at 80 ° C. before curing according to the dynamic viscoelasticity measurement of the adhesive layer (1) is 0.232, and the storage elastic modulus G ′ (80ad) at 80 ° C. of the adhesive layer (1) is 0. .343 MPa. These measuring methods will be described later.

<Adhesive layer (2)>
It was produced in the same manner as the adhesive layer (1) except that the film thickness was 40 μm. The loss tangent tan δ (80ad) at 80 ° C. before curing according to the dynamic viscoelasticity measurement of the adhesive layer (2) is 0.232, and the storage elastic modulus G ′ (80ad) at 80 ° C. of the adhesive layer (2) is 0. .343 MPa.

(Preparation of adhesive film)
<Adhesive film (1)>
Curing agent for acrylic copolymer having a weight average molecular weight of 800,000 synthesized by radical polymerization of 65 parts by weight of butyl acrylate, 25 parts by weight of 2-hydroxyethyl acrylate and 10 parts by weight of acrylic acid, and dropping reaction of 2-isocyanate ethyl methacrylate. As a photopolymerization initiator, 3 parts by weight of polyisocyanate and 1 part by weight of 1-hydroxy-cyclohexyl-phenyl-ketone as a photoinitiator were added and mixed to obtain an adhesive layer composition.
After coating the prepared pressure-sensitive adhesive layer composition on a coating film (silicone mold-released PET film (Teijin: Hupyrex S-314, thickness 25 μm)) to a dry film thickness of 10 μm, Dry at 120 ° C. for 3 minutes. Thereafter, the pressure-sensitive adhesive layer composition applied to the coating film was converted into an 80-μm thick ethylene-methacrylic acid- (2-methyl-propyl acrylate) terpolymer-Zn as the base film 12a. ++ — An adhesive film (1) was prepared by transferring onto an ionomer resin (Mitsui / DuPont Polychemical Co., Ltd., Himiran AM-7316) film. The loss tangent tan δ (80 film) at 80 ° C. by dynamic viscoelasticity measurement of the adhesive film (1) was 0.098.

<Adhesive film (2)>
It was produced in the same manner as the adhesive film (1) except that the resin film thickness (adhesive film thickness) was 100 μm. The loss tangent tan δ (80 film) at 80 ° C. by dynamic viscoelasticity measurement of the adhesive film (2) was 0.098.

<Adhesive film (3)>
The resin used for the base film 12a is an elastomer of PP: HSBR = 80: 20 (polypropylene (PP) is Novatec FG4 manufactured by Nippon Polychem Co., Ltd., and hydrogenated styrene butadiene (HSBR) is Dynalon manufactured by JSR Corporation. 1320P was used) and was prepared in the same manner as the adhesive film (1) except that the resin film thickness was 70 μm. The loss tangent tan δ (80 film) at 80 ° C. by dynamic viscoelasticity measurement of the adhesive film (3) was 0.068.

<Adhesive film (4)>
It was produced in the same manner as the adhesive film (3) except that the resin film thickness was 100 μm. The loss tangent tan δ (80 film) at 80 ° C. by dynamic viscoelasticity measurement of the adhesive film (4) was 0.068.

(Loss tangent and storage modulus of adhesive layers (1) and (2))
Two separator films (PET) coated with an adhesive layer (1) of 20 μm were prepared, the adhesive layers (1) were bonded together, the separator film was peeled off, and then the adhesive film was further applied to the separator film. (1) The process of laminating 20 μm coated layers with the adhesive layers (1) was repeated until the thickness reached 1 mm, punched out to 8 mmφ, and used as a sample of the adhesive layer (1).
Using a dynamic viscoelasticity measuring device ARES (manufactured by Rheologica), the rate of temperature increase from room temperature to 200 ° C. under shear conditions of sample thickness 1 mm, plate diameter 8 mmΦ, frequency 1 Hz for the sample of adhesive layer (1) before curing Loss tangent tan δ (80ad) and storage elastic modulus G ′ (80ad) at 80 ° C. when the temperature was raised at 10 ° C./min were measured.
The loss tangent tan δ (80ad) and storage elastic modulus G ′ (80ad) of the adhesive layer (2) were also measured in the same manner as the adhesive layer (1).

(Loss tangent of adhesive films (1) to (4))
Using a dynamic viscoelasticity measuring device RSAIII (manufactured by TA Instruments), the temperature was increased from −10 ° C. to 150 ° C. under a temperature rising rate of 10 ° C./min under a sample width of 5 mm, a distance between chucks of 20 mm, and a frequency of 10 Hz. Loss tangent at 80 ° C. when heated was measured.

Table 1 shows the characteristic evaluation performed for each of Examples 1 to 5 and Comparative Examples 1 to 3.
(Production and characteristic evaluation of dicing die bond sheet)
The adhesive layers of the wafer processing tapes of Examples 1 to 5 and Comparative Examples 1 to 3 were attached to the back surface of a silicon wafer (semiconductor wafer 1) having a thickness of 100 μm (see FIG. 2), 7.5 mm × 7. After dicing to 5 mm, an ultraviolet ray of 200 mJ / cm ² was irradiated using a metal halide lamp. Thereafter, for each sample, a pickup device (CAP-300II manufactured by Canon Machinery Co., Ltd.) was used to try to pick up 100 chips, and among them, the number of successful pickup chips was counted. At that time, if a plurality of chips were picked up at the same time, it was regarded as a pickup failure.

In Examples 1 to 4, it can be seen from Table 1 that the pick-up failure rate at which a plurality of chips are picked up simultaneously is “0” and the double die error in which adjacent chips are lifted together is reduced.
In Example 5, the pickup defect rate is “1”, and it can be seen that the double die error in which the adjacent chips are lifted together is reduced.
On the other hand, in Comparative Examples 1, 2, and 3, the pick-up defect rate is high as “13”, “22”, and “34”, respectively, and it can be seen that a double die error in which adjacent chips are lifted together occurs. .

  According to the wafer processing tape 10 according to the present embodiment, since the value A expressed by the above formula (1) is 0.043 or more, the adhesive is bonded when the adhesive layer 13 receives a force pushed by the dicing blade 21. The agent layer 13 is less likely to be deformed (elastically deformed), and the protrusion of the adhesive layer 13 from the semiconductor chip 2 is reduced. Thereby, the adhesive bond layer 13 is not re-fused. Therefore, it is possible to suppress the occurrence of a double die error in which adjacent chips are lifted together in the pickup process.

1: Semiconductor wafer 2: Semiconductor chip (semiconductor element)
10: Wafer processing tape 12: Adhesive film 12a: Base film 12b: Adhesive layer 13: Adhesive layer

Claims (1)

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,
The thickness of the adhesive layer is t (ad) [um], the storage elastic modulus of the adhesive layer at 80 ° C. is G ′ (80ad) [MPa], and the tan δ of the adhesive layer at 80 ° C. is tan δ (80ad). When the thickness of the adhesive film is t (film) [um] and tan δ at 80 ° C. of the adhesive film is tan δ (80 film), the value A represented by the formula (1) is 0.043 or more. And

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