JP2017059709A - Method of producing dicing die-bonding film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a dicing die-bonding film, which is capable of suppressing a dicing film and a wafer ring from being separated and a dicing film and a die-bonding film from being separated in dicing, and which is also improved in machinability.SOLUTION: A dicing die-bonding film includes a support base material (1), a UV curable adhesive layer (2), and a die adhesive layer (3) having an area less than that of the UV curable adhesive layer which are laminated in the order. The UV curable adhesive layer (2) is semi-cured by performing UV irradiation on a range (2a) smaller than an area of the UV curable adhesive layer (2) in a surface where the die adhesive layer (3) is projected on the UV curable adhesive layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a manufacturing method of a dicing die bond film.

The dicing die-bonding film is an effect of an adhesive that fixes a semiconductor chip to an adherend such as a lead frame (mounting process) on a dicing film in which a UV (ultraviolet) curable adhesive layer is disposed on a support substrate. It is an integrated film in which die-bonding films having The usage is shown below.
First, after adjusting the thickness of the semiconductor wafer on which the electric circuit pattern is formed by backside polishing as necessary, the wafer and the dicing die bond film are attached to the wafer ring. In order to remove cutting debris, the semiconductor wafer is diced with a blade while being washed with an appropriate hydraulic pressure (usually about 200 kPa) (dicing step). Next, UV irradiation is performed, the adhesive layer is UV cured, pickup is performed, a chip with a die bond film is fixed to an adherend such as a lead frame (mounting process), and the process proceeds to the bonding process.

  The conventional dicing die bonding film has the following problems. In the dicing process, peeling of the dicing film and wafer ring (hereinafter referred to as wafer ring peeling) or peeling of the dicing film and die bond film (hereinafter referred to as die bond film peeling) due to the liquid pressure of the cleaning liquid used for removing the cutting layer. In addition, chip chipping due to poor cutting, which occurs when dicing an uncured adhesive layer, can be mentioned. Further, in the bonding process, contamination of the wire pad due to cutting dust attached to the chip is a problem. So far, the above-described problems have been solved by adjusting the composition of the pressure-sensitive adhesive layer of the dicing tape.

  However, when the adhesive strength when uncured is increased, peeling of the wafer ring can be suppressed, but the adhesive layer is soft, so that the machinability is poor, chip cracking and the peelability after UV curing are deteriorated, and pickup failure occurs. Further, when the adhesive strength when uncured is lowered, the pick-up property is improved, but the wafer ring is peeled off, and it is difficult to solve the above trade-off only by adjusting the characteristics of the adhesive layer.

  In order to overcome such problems, various improved methods have been proposed (see, for example, Patent Document 1). In Patent Document 1, the wafer ring sticking portion is provided with a strong adhesive layer on the support substrate to suppress peeling of the wafer ring, while a weak adhesive layer is provided on the strong adhesive layer on the inner periphery of the wafer sticking portion. It tries to solve the above trade-off by providing it.

  However, when this method is used, the above trade-off can be solved, but the manufacturing process and material costs are added to form a three-layer structure, which increases costs.

JP 2011-9732 A

  An object of the present invention is to provide a method of manufacturing a dicing die bond film that can suppress peeling of the dicing film and the wafer ring during dicing, and peeling of the dicing film and the die bond film, and has improved machinability. And

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a manufacturing method of a dicing die-bonding film shown below and have completed the present invention.

  That is, in the present invention, the UV curable adhesive layer (2) is disposed on the support substrate (1), and the UV curable adhesive layer (2) has a smaller area than the UV curable adhesive layer (2). In the manufacturing method of the dicing die-bonding film in which the die-adhesive layer (3) is provided, from the area of the UV-curable adhesive layer (2) in the plane where the die-adhesive layer (3) is projected onto the UV-curable adhesive layer Provided is a method for producing a dicing die-bonding film, which is semi-cured by UV irradiation in a small range (2a).

  After UV irradiation, the UV curable pressure-sensitive adhesive layer (2) includes a semi-cured pressure-sensitive adhesive layer (2a) and (2b) excluding (2a), wherein (the adhesive strength of the semi-cured pressure-sensitive adhesive layer (2a)) < By satisfying (adhesive strength of the adhesive layer (2b)), wafer ring peeling during dicing can be suppressed. Moreover, since the die bond film peeling at the time of dicing starts peeling from the outer edge part of the film, the UV curable adhesive layer inside the die bond film is irradiated with UV as in the present invention to suppress the die bond film peeling. it can. In addition, since the adhesive layer (2a) is UV-cured and has an appropriate adhesive force, the machinability is improved, chip chipping is suppressed, and even a chip of 10 mm × 10 mm or less is chipped during dicing. It becomes possible to suppress the jump. With such a manufacturing method, the dicing die-bonding film can achieve both the chip holding force during dicing and the peelability during pick-up.

  Moreover, the dicing die-bonding film of the present invention is a UV curable type after either the UV curable adhesive layer (2) is disposed on the support substrate (1) or after the die bonding layer (3) is provided. The adhesive layer (2) can be semi-cured by UV irradiation.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the dicing die-bonding film which can suppress peeling of the dicing film and wafer ring at the time of dicing, and peeling of a dicing film and a die-bonding film, and improved machinability is provided. Can do.

It is a schematic cross section of one embodiment of a dicing die bond film of the present invention. It is a schematic cross section of one embodiment of a dicing die bond film of the present invention.

  Hereinafter, preferred embodiments of a method for producing a dicing die-bonding film of the present invention will be described in detail with reference to the drawings. FIG. 1 and FIG. 2 show cross-sectional views of embodiments of the dicing die-bonding film of the present invention, both of which place a UV curable adhesive layer (2) on a support substrate (1), In a dicing die-bonding film in which a die-bonding layer (3) having a smaller area than the UV-curable pressure-sensitive adhesive layer (2) is provided on the UV-curable pressure-sensitive adhesive layer (2), the die adhesive layer (3) is UV-curable pressure-sensitive adhesive. Semi-curing is performed by irradiating UV to a range smaller than the area of the UV curable adhesive layer (2) in the plane projected onto the layer (2).

  The die adhesion layer (3) can be attached to the entire surface of the wafer (W) and is larger than the area of the wafer (W) and larger than the outer periphery of the semi-cured adhesive layer (2a), and from the wafer ring (WR). small. The wafer ring (WR) is fixed to the UV curable adhesive layer (2) excluding the semi-cured adhesive layer (2a) by using a wafer ring (WR) having a size corresponding to the wafer (W).

  As shown in FIG. 2, when the wafer (W) is circular with a diameter (m1), the UV semi-cured portion adhesive layer (2a) is also circular, and the diameter (m2) satisfies (m2)> (m1). Design to be satisfied. The difference in diameter ((m2)-(m1)) is appropriately determined depending on the size of the wafer. When the wafer diameter is 1 to 12 inches (about 300 mm), the difference is 0.1 to 30 mm or more. And The range of 0.1-0.5 mm is preferable, and 0.5 mm or more is still more preferable. However, the relationship between the diameter (m3) of the die bonding layer (3) and the diameter (m2) of the semi-cured adhesive layer (2a) is designed so that (m3)> (m2). The difference in diameter ((m3)-(m2)) is not particularly limited.

  In FIG. 1, the UV curable adhesive layer (2) has a different adhesive strength between the semi-cured adhesive layer (2a) and the other part (2b), and the (adhesive strength of the semi-cured adhesive layer (2a)) < Adjustment is made to satisfy the relationship of (adhesive strength of the adhesive layer (2b)).

  The semi-cured adhesive layer (2a) is semi-cured by UV irradiation either after the UV curable adhesive layer (2) is formed on the support substrate (1) or after the die bonding layer (3) is formed. And may be formed.

  Examples of the material for the supporting substrate (1) include materials that can be expanded (radially stretched) during the die bonding step. Specifically, polyolefins such as crystalline polypropylene, amorphous polypropylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, low-density linear polyethylene, polybutene, and polymethylpentene, ethylene-vinyl acetate Copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, polyurethane Polyester such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate, polyimide, polyetheretherketone, polyetherimide, polyamide, wholly aromatic polyamide, polyphenylsulfide, aramid (paper), glass, glass , Fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulosic resin, silicone resin, and mixtures of these with plasticizer, silica, anti-blocking material, slip agent, antistatic agent, etc. Among them, polypropylene, polyethylene-polypropylene random copolymer, and polyethylene-polypropylene block copolymer are good materials from the viewpoints of Young's modulus, stress relaxation, melting point, and other properties, price, and waste material recycling after use. In addition, since the surface modification effect by ultraviolet rays is easily obtained, it is more preferable. The support substrate (1) may be one of the above components or may be composed of two or more materials.

  The surface of the support substrate (1) is subjected to a surface treatment for improving adhesion, retention and the like with the UV curable adhesive layer (2), for example, chromic acid treatment, ozone exposure, flame exposure, corona high piezoelectric impact exposure, Chemical or physical treatment such as ionizing radiation treatment, and coating treatment with a primer (for example, an adhesive substance described later) can be applied.

  The thickness of the support substrate (1) is not particularly limited and can be appropriately determined, but can be about 80 to 100 μm.

  The UV curable adhesive layer (2) is formed of a UV curable adhesive. The UV curable pressure-sensitive adhesive increases the degree of crosslinking by the action of a photopolymerization initiator or a crosslinking agent by irradiation with ultraviolet rays or the like, and cures the irradiated portion. Since the degree of cure can be adjusted by the blending amount of the photopolymerization initiator and the crosslinking agent, the adhesive layer (2a) and the adhesive layer which are semi-cured by irradiating ultraviolet rays to desired portions of the UV curable adhesive layer (2) The difference in adhesive strength with (2b) can be easily adjusted.

  Further, the adhesive force can be easily adjusted depending on the UV illuminance and the irradiation amount. Since the die-bonding layer (3a) is provided on the semi-cured pressure-sensitive adhesive layer (2a), the interface between the semi-cured pressure-sensitive adhesive layer (2a) and the die-bonding layer (3a) has a property of easily peeling off during the pickup process. On the other hand, the adhesive layer (2b) that has not been irradiated with UV has sufficient adhesive strength.

  UV irradiation to the UV curable pressure-sensitive adhesive layer (2) was carried out after (i) placing the UV curable pressure-sensitive adhesive layer (2) on the supporting substrate (1) or (ii) providing the die-adhesive layer (3). Any of later may be sufficient. When the pressure-sensitive adhesive layer (2a) semi-cured by the method (i) is formed, a result that the pickup property is improved is obtained as compared with the case where UV irradiation is performed after dicing. On the other hand, in the method (ii), it is possible to produce a dicing die-bonding film that can suppress chip skipping even with a smaller chip during dicing.

  In the case of curing inhibition by oxygen during UV irradiation, the surface of the UV curable adhesive layer (2) is preferably shielded from oxygen (air). For example, a method of covering the surface of the UV curable pressure-sensitive adhesive layer (2) with a separator, a method of performing UV irradiation in a nitrogen gas atmosphere, and the like can be mentioned.

  The thickness of the UV curable pressure-sensitive adhesive layer (2) is not particularly limited, but is preferably about 1 to 50 μm from the viewpoints of chip chip prevention and compatibility of fixing and holding of the adhesive layer. Preferably they are 2-40 micrometers and 5-30 micrometers.

  The die bonding layer (3) is preferably one that can be formed into a sheet. Specifically, for example, a thermoplastic resin and a thermosetting resin can be suitably used. In particular, a thermosetting resin is preferable in that the temperature at which the wafer is bonded can be lowered, and excellent heat resistance can be obtained by curing. A die adhesive can be used individually or in combination of 2 or more types. The die bonding layer (3) is preferably one that can be bonded to a semiconductor wafer or the like at 70 ° C. or lower.

  Thus, the UV curable adhesive layer (2) is disposed on the supporting substrate (1), and the UV curable adhesive layer (2) is semi-cured by UV irradiation and the unirradiated part (2b) ) And a dicing die-bonding film provided with a die-adhesive layer (3).

  Hereinafter, the present invention will be described more specifically with reference to examples.

(Example)
[Preparation of die adhesive layer]
YDCN-703 (manufactured by Toto Kasei Co., Ltd., cresol novolac type epoxy resin, epoxy equivalent 210, molecular weight 1200, softening point 80 ° C.) 55 parts by mass as an epoxy resin, and Mirex XLC-LL (manufactured by Mitsui Chemicals, phenol) as a phenol resin Resin, hydroxyl group equivalent 175, water absorption rate 1.8%, heating weight reduction rate at 350 ° C. 4%) 45 parts by mass, silane coupling agent NUCA-189 (manufactured by NUC, γ-mercaptopropyltrimethoxysilane) 1 0.7 parts by mass and NUCA-1160 (manufactured by NUC, γ-ureidopropyltriethoxysilane) 3.2 parts by mass, as a filler Aerosil R972 (silica surface coated with dimethyldichlorosilane, in a reactor at 400 ° C. Hydrolyzed organic groups such as methyl groups on the surface Cyclohexanone was added to a composition consisting of 32 parts by mass of a filler, Nippon Aerosil Co., Ltd. trade name, silica, average particle size 0.016 μm), and the mixture was stirred and mixed, and further kneaded for 90 minutes using a bead mill.
280 parts by mass of acrylic rubber HTR-860P-3 (manufactured by Nagase ChemteX Corporation, weight average molecular weight 800,000) containing 3% by mass of glycidyl acrylate or glycidyl methacrylate, and Curazole 2PZ-CN (Shikoku Chemicals) as a curing accelerator 0.5 part by mass of a trade name, 1-cyanoethyl-2-phenylimidazole) manufactured by Kogyo Co., Ltd. was added, mixed with stirring, and vacuum degassed to obtain a varnish.

The varnish was coated on a polyethylene terephthalate tape having a release treatment of 38 μm in thickness, dried by heating at 140 ° C. for 5 minutes to form a B-stage coating film having a thickness of 20 μm, and provided with a carrier tape A die bonding layer (3) was produced.
[Synthesis of acrylic resin for adhesive layer]

  To an autoclave with a capacity of 4000 ml equipped with a three-one motor, a stirring blade and a nitrogen introduction tube, 1000 g of ethyl acetate, 650 g of 2-ethylhexyl acrylate, 350 g of 2-hydroxyethyl acrylate, and 3.0 g of azobisisobutyronitrile were blended uniformly. Stir until. Thereafter, bubbling was performed at a flow rate of 100 ml / min for 60 minutes to degas dissolved oxygen in the system. The temperature was raised to 60 ° C. over 1 hour, and the temperature was raised and polymerized for 4 hours. Thereafter, the temperature was raised to 90 ° C. over 1 hour, further maintained at 90 ° C. for 1 hour, and then cooled to room temperature.

  Next, 1000 g of ethyl acetate was added to the autoclave and stirred for dilution. After adding 0.1 g of methoquinone as a polymerization inhibitor and 0.05 g of dioctyltin dilaurate as a urethanization catalyst, 100 g of 2-methacryloxyethyl isocyanate (Karenz MOI: product name manufactured by Showa Denko KK) was added, After reacting at 70 ° C. for 6 hours, it was cooled to room temperature. Thereafter, ethyl acetate was added to adjust the non-volatile content in the acrylic resin solution to 35% by mass to obtain an acrylic resin solution having a functional group capable of chain polymerization.

  When the acid value and hydroxyl value of this resin were measured according to JIS K0070, no acid value was detected. When the hydroxyl value was determined, it was 121 mgKOH / g. Moreover, the obtained acrylic resin was vacuum-dried at 60 ° C. for 12 hours, and the obtained solid content was subjected to elemental analysis with a fully automatic elemental analysis device varioEL (manufactured by Elemental Co.), and 2-methacrylic acid introduced from the nitrogen content. The content of roxyethyl isocyanate was calculated to be 0.59 mmol / g. Also, SD-8022 / DP-8020 / RI-8020 (manufactured by Tosoh Corporation) is used, and Gelpack GL-A150-S / GL-A160-S (manufactured by Hitachi Chemical Co., Ltd.) is used as the column, and the eluent is used. As a result of GPC measurement using tetrahydrofuran, the polystyrene-reduced weight average molecular weight was 420,000.

[Preparation of adhesive layer]
100 g of an acrylic resin solution having a chain-polymerizable double bond obtained by the above-mentioned method as a solid content and polyfunctional isocyanate (Nihon Polyurethane Industry Co., Ltd., Coronate L, solid content 75%) as a solid content as a solid content. 12.0 g, 1 g of 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure 184) as a photopolymerization initiator, and ethyl acetate was added so that the total solid content was 27% by mass. The mixture was stirred for 10 minutes to obtain an adhesive layer varnish.

  Adjust the gap so that the adhesive layer has a thickness of 30 μm using an applicator on a polyethylene terephthalate tape with a width of 400 mm, a length of 400 mm, and a thickness of 38 μm. The coating was performed while drying at 80 ° C. for 5 minutes.

  Separately, the polyolefin tape of 400 mm square and 80 μm thickness and the adhesive layer side of the above-mentioned polyethylene terephthalate tape with adhesive layer are bonded together at room temperature, and pressure is applied with a rubber roll to form the UV curable adhesive layer (2) on the polyolefin tape. Transcribed. Then, the UV curable adhesive layer (2) with a cover tape was obtained by leaving it to stand at room temperature for 3 days.

[Production of dicing die bond film]
The UV curable adhesive layer (2) was cut into a circle having a diameter of 370 mm. Next, the UV curable pressure-sensitive adhesive layer (2) corresponding to the wafer bonding part was UV-irradiated under the conditions of 90 mW / cm ² and 5 mJ to be semi-cured. Finally, the die bonding layer (3) and the UV adhesive layer (2) prepared by the above method were bonded at room temperature to obtain a dicing die bond film. The die bonding layer (3) was bonded in a shape having a diameter 30 mm larger than that of the wafer.
In addition, QRE-4013 (made by Oak Manufacturing Co., Ltd.) was used for the UV irradiation apparatus.

(Comparative example)
A dicing die-bonding film was produced in the same manner as in Example except that the adhesive layer and the adhesive layer were bonded together without irradiating UV.

(Measurement of peel strength at the interface between the dicing film and the die bond film)
The dicing die-bonding films produced in the examples and comparative examples were formed into strips having a width of 25 mm and a length of 100 mm, and the dicing film and the die-bonding film were 90 degrees using Autograph AGS-1000G (manufactured by Shimadzu Corporation). The peel strength was measured when the film was peeled off at an angle and a pulling speed of 300 mm / min. At this time, the peel strength was measured at the wafer attaching portion and at the other two locations.

  Using the dicing die-bonding films of the above Examples and Comparative Examples, the semiconductor wafer was actually diced and die-bonded in the following manner, and its performance was evaluated. The results are shown in Table 1.

(Confirmation of wafer ring peeling, DB film peeling, machinability, pickup)
After dicing and die bonding film is roll-bonded to a mirror wafer with a thickness of 35 μm by polishing the back surface of a semiconductor wafer at 65 ° C., it is diced to a 10 mm square chip size, wafer ring peeling, die bonding film peeling, machinability Was evaluated. In this evaluation, neither the dicing die-bonding film of the example nor the comparative example was observed to peel off the wafer ring at the time of dicing, and the die-bonding film was peeled off, but the edge was distorted in the comparative example when the dicing line was observed. On the other hand, in the example, it was found that the machinability was improved without distortion at the edge. Next, a pickup evaluation was performed. Comparing the minimum push-up height that could lift all the chips when picking up 20 sheets, it was confirmed that the example improved the pickup height by 50 μm compared to the comparative example.

(Dicing conditions)
Dicing machine: DFD-6361 (manufactured by DISCO Corporation)
Dicing speed: 50 mm / sec Dicing blade: ZH05-SD4000-N1-70-BB (manufactured by Disco Corporation) Number of revolutions: 40,000 min ⁻¹
Cutting height: 90 μm
Cutting method: Single cut A mode Chip size: As appropriate (10mm square)
(Wafer grinding conditions)
Grinding device: DGP-8761 (manufactured by DISCO Corporation)
Wafer: 12 inch diameter (grind the back to 35μm thickness)
Wafer bonding apparatus: DFM-2800 (manufactured by DISCO Corporation)
(Expanding condition)
Withdrawal amount: 3mm
Die bonder: DB-800HSD (manufactured by Hitachi, Ltd.)
Pushing method: 14 pins Pushing speed: 1mm / s

※表１中、ＤＢ：ダイボンド、ＤＣ：ダイシング、ＰＵ：ピックアップを略して記載した。

* In Table 1, DB: die bond, DC: dicing, PU: pickup are abbreviated.

1: Support base material 2: UV curable adhesive layer 3: Die adhesion layer W: Wafer WR: Wafer ring

Claims (3)

  A UV (ultraviolet) curable adhesive layer (2) is disposed on the support substrate (1), and a die having a smaller area than the UV curable adhesive layer (2) is disposed on the UV curable adhesive layer (2). In the manufacturing method of the dicing die-bonding film provided with the adhesive layer (3), the area of the UV curable adhesive layer (2) in the plane where the die adhesive layer (3) is projected onto the UV curable adhesive layer is smaller. A method for producing a dicing die-bonding film, characterized in that UV irradiation is performed in a range (2a) and semi-curing is performed. After the UV irradiation, the UV curable adhesive layer (2) includes a semi-cured adhesive layer (2a) and a portion (2b) excluding the (2a),
The manufacturing method of the dicing die-bonding film of Claim 1 which satisfies the relationship of (adhesive strength of the semi-hardened adhesive layer (2a)) <(adhesive strength of the adhesive layer (2b)).   UV irradiation to the UV curable adhesive layer (2) either after the UV curable adhesive layer (2) is disposed on the support substrate (1) or after the die bonding layer (3) is provided. The method for producing a dicing die-bonding film according to claim 1 or 2, which is semi-cured.

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