JP2012209363A - Dicing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dicing film in which generation of chips or whiskers of a substrate is reduced during dicing and which has adequate strength and excellent appearance.SOLUTION: The dicing film has an adhesive layer at least on one surface of a substrate film. The substrate film contains polyethylene (A) of which the melting point is 110°C or less and the molecular weight distribution is 5 or less and styrene system elastomer (B). The polyethylene (A) is a linear low density polyethylene polymerized by a metallocene catalyst.

Description

  The present invention relates to a dicing film.

  In the process of manufacturing a semiconductor device, a dicing film is used when cutting a semiconductor member such as a semiconductor wafer or a package. The dicing film is used for picking up the semiconductor wafer or the like by attaching a semiconductor member, dicing (cutting, dividing into pieces), and expanding the dicing film.

  In general, a dicing film is composed of a base film and an adhesive layer. Conventionally, a polyvinyl chloride (PVC) resin film has been often used as a base film. However, from the prevention of contamination of semiconductor members due to the adhesion of plasticizers contained in PVC resin films and the growing awareness of environmental issues, recently, such as olefin resins, ethylene vinyl alcohol resins and ethylene methacrylate acrylate resins, etc. A base film using a non-PVC resin-based material has been developed (see, for example, Patent Document 1).

In recent years, as semiconductor members have become smaller and thinner, if the thickness accuracy of the dicing film varies, there is a difference in the way of contact of the dicing blade in the dicing process, and semiconductor wafer cracking is likely to occur. Cause problems. In addition, if there is variation in the film thickness accuracy, semiconductor component cut residue, chips during dicing, and substrate whiskers (whisker-like cut residue extending from the substrate film cut line) are generated and adhere to the semiconductor device. Such a problem also occurs. In particular, when a semiconductor package is cut, a thick dicing blade is often used, and the problem of generation of substrate whiskers appears more markedly than when a semiconductor wafer is cut. As means for solving such a problem, for example, Japanese Patent Application Laid-Open No. 5-21234 has proposed an adhesive film in which a base film is irradiated with radiation. However, this pressure-sensitive adhesive film is not preferable in terms of quality because damage to the film due to radiation irradiation is large, and it is difficult to obtain a film having a good appearance. In addition, it is not preferable in terms of price because of the great cost in film production.

In addition, after dicing by dicing the semiconductor member, the dicing film is expanded in order to widen the gap between the semiconductor members. However, if the base material does not have sufficient toughness, the dicing film may break when expanded. . Therefore, there is a need for a dicing film that can suppress substrate whiskers during dicing and that does not break during expansion.

JP2003-257893A

Japanese Patent Laid-Open No. 5-21234

An object of the present invention is to provide a dicing film that generates less chips and substrate whiskers in a dicing process during semiconductor manufacturing and has a suitable expandability.

The dicing film according to the present invention is a dicing film having an adhesive layer on at least one surface of a base film, wherein the base film has a melting point of 110 ° C. or lower and a weight average molecular weight / number average molecular weight. The polyethylene (A) having a molecular weight distribution (hereinafter also simply referred to as “molecular weight distribution”) of 5 or less and the styrene elastomer (B) are included.

  In the dicing film according to the present invention, the polyethylene (A) may be a linear low density polyethylene.

  The dicing film according to the present invention can be a linear low density polyethylene obtained by polymerizing the polyethylene (A) with a metallocene catalyst.

In the dicing film according to the present invention, the styrenic elastomer (B) can be a styrene-ethylene-butylene-styrene copolymer.

  In the dicing film according to the present invention, the weight ratio (A / B) of the polyethylene (A) and the styrene-based elastomer (B) in the base film is 30/70 or more and 70/30 or less. it can.

  In the dicing film according to the present invention, the breaking energy of the base film in the following breaking energy evaluation test can be 15 mJ or more.

<Break energy evaluation test>
A cross cut is made on one side of the film under the following cut preparation conditions.
With the face where the cut was made facing down, with the following drop weight test conditions for the intersection of the cross cut,
A falling weight test is performed, and the potential energy at which the base material breaks is defined as the breaking energy.
<Cut cutting conditions>
Using a blade, create a cut with a depth of 80 μm and a length of 40 mm or more in a cross shape.
<Falling weight test conditions>
Weight: 1.02 kg
Conical tip shape: Fixed shape of hemispherical test piece with a diameter of 20 mm: Circular shape with a diameter of 40 mm

According to the present invention, it is possible to provide a dicing film that has less generation of chips and substrate whiskers in a dicing process during semiconductor manufacturing and that has suitable expandability.

It is a schematic sectional drawing which shows an example of the dicing film which concerns on this invention. It is the film for a test after cross cut creation used for the fracture energy evaluation test concerning the present invention.

  The dicing film according to the present invention is used when dicing (cutting) a semiconductor member such as a semiconductor wafer or a semiconductor package mainly in a process of manufacturing a semiconductor. For example, it is attached to a semiconductor wafer, a semiconductor package or the like, and is used for picking up a semiconductor element obtained by cutting the semiconductor wafer by dicing the semiconductor wafer or the like and then expanding the wafer.

  The dicing film of the present invention is derived from the resin by using polyethylene (A) having a melting point of 110 ° C. or lower and a molecular weight distribution of 5 or lower and a styrene elastomer (B) as constituents of the base film. It is possible to reduce the occurrence of substrate whiskers and to design with an emphasis on expandability of the dicing film. The structural requirements of the present invention will be described below with reference to the drawings.

<Base film>
The dicing film 10 according to the present invention has at least a base film 1 and an adhesive layer 2 as illustrated in FIG. The base film 1 includes polyethylene (A) having a melting point of 110 ° C. or lower and a molecular weight distribution of 5 or lower, and a styrene elastomer (B). The polyethylene (A) is preferably a linear low density polyethylene, and more preferably a linear low density polyethylene polymerized with a metallocene catalyst. By using linear low density polyethylene polymerized with a metallocene catalyst, generation of chips and substrate whiskers during dicing can be further reduced.

  Examples of the styrene elastomer (B) include styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, styrene-butadiene-butylene-styrene copolymer, styrene-isoprene copolymer, and styrene-isoprene-styrene. Copolymer, styrene-ethylene-isoprene-styrene copolymer, hydrogenated vinyl (styrene-ethylene-isoprene-styrene) copolymer, hydrogenated vinyl (styrene-isoprene-styrene) copolymer, styrene-ethylene-butylene -Styrene copolymers may be mentioned. Among these, a styrene-ethylene-butylene-styrene copolymer is particularly preferable from the viewpoint of increasing the breaking strength of the base material layer and reducing chips and whiskers during dicing.

  The weight ratio (A / B) of the polyethylene (A) and the styrene elastomer (B) in the base film 1 is preferably 30/70 or more and 70/30 or less, and the weight ratio of the polyethylene (A) When the value is equal to or higher than the lower limit of the range, the effect of suppressing the base whiskers of the base film is excellent.

  As described above, the combined use of polyethylene (A) having a melting point of 110 ° C. or less and a molecular weight distribution of 5 or less and the styrene elastomer (B) is excellent in suppressing substrate whisker, and suitable for a semiconductor member processing step. It becomes the dicing film used.

  Various resins and additives can be added to the base film of the dicing film according to the present invention in accordance with the purpose within a range not impairing the effects of the present invention. For example, in order to impart antistatic properties, a polymer type antistatic agent such as a polyether / polyolefin block polymer or a polyether ester amide block polymer, carbon black or the like can be added. In the case of imparting an antistatic effect, an ion conductive antistatic agent using a polyether / polyolefin copolymer is preferable from the viewpoint of compatibility with the olefin resin. Further, the elongation at break can be increased by applying an elastomer.

  The thickness of the substrate film of the dicing film is preferably 50 μm or more and 150 μm or less, more preferably 70 μm or more and 100 μm or less for semiconductor wafer dicing. For dicing special members such as semiconductor packages, the thickness is preferably from 100 μm to 300 μm, and more preferably from 150 μm to 200 μm. By setting it as the said range lower limit value or more, the base film at the time of expansion will become difficult to fracture | rupture, and generation | occurrence | production of the base beard at the time of dicing can be suppressed by setting it as the said range upper limit value or less.

  In the dicing film according to the present invention, after dicing the semiconductor member, the dicing film is expanded (stretched) in a state where the semiconductor member is attached so that the semiconductor member can be easily picked up, thereby widening the interval between the semiconductor members. In order to obtain suitable expandability, it is preferable that the breaking energy of the base film in the following breaking energy evaluation test is 15 mJ or more. By setting it to the above lower limit value or more, breakage during expansion can be suppressed. The breaking energy can be appropriately adjusted by changing the blending ratio of the elastomer in the base film. For example, the breaking energy can be increased by blending an elastomer.

<Break energy evaluation test>
As shown in FIG. 2, a cross cut 3 is produced on one side of the film 1 under the following cut production conditions.
With the face where the cut was made facing down and the intersection of the cross cut 3 under the following drop weight test conditions,
A falling weight test is performed, and the potential energy at which the base material breaks is defined as the breaking energy.
<Cut cutting conditions>
Using a blade, a cut having a depth of 80 μm and a length of 40 mm or more is made into a cross.
<Falling weight test conditions>
Weight: 1.02 kg
Conical tip shape: Fixed shape of hemispherical test piece with a diameter of 20 mm: Circular shape with a diameter of 40 mm

(Adhesive layer)
As illustrated in FIG. 1, an adhesive layer 2 is provided on at least one surface of a base film 1 of a dicing film 10 according to the present invention. Examples of the resin composition used for the pressure-sensitive adhesive layer 2 include an acrylic pressure-sensitive adhesive, a UV curable urethane acrylate resin, and an isocyanate-based crosslinking agent. Among these, it is preferable to use an acrylic pressure-sensitive adhesive containing a polar group in order to suppress the mounting of semiconductor members, edge material jumping and chipping. As the acrylic adhesive, for example, carboxyl group-containing butyl acrylate is preferable. By using carboxyl group-containing butyl acrylate, it becomes particularly suitable for mounting of semiconductor members, suppression of jumping of end materials, and chipping.

  The thickness of the adhesive layer 2 is preferably 3 μm or more and 100 μm or less, and preferably 3 μm or more and 10 μm or less for semiconductor wafer dicing of a dicing film. Further, for dicing special members such as packages, it is preferably 10 μm or more and 30 μm or less. By setting it to the range lower limit value or more, the holding power of the adherend is excellent, and by setting it to the range upper limit value or less, the workability during dicing is excellent.

<Example of manufacturing method of dicing film>
The pressure-sensitive adhesive layer 2 of the dicing film 10 according to the present invention is a coating liquid obtained by appropriately dissolving or dispersing a resin used as the pressure-sensitive adhesive layer 2 in a base film 1 or a resin film including the base film 1 in a solvent. It is formed by applying and drying by a known coating method such as roll coating or gravure coating.

  The dicing film according to the present invention can be provided with other resin layers depending on the purpose within a range not impairing the effects of the present invention.

The present invention will be described in more detail by way of examples, but this is merely an example, and the present invention is not limited thereby.
<Preparation of base film>
After the following raw materials were mixed by dry blending at a weight blending ratio shown in Table 1, Φ50 mm extruder (L / D = 25 unimelt pin screw, screw compression ratio = 2.9), 300 mm width coat hanger die (lip gap = 0.5 mm) and extrusion temperature = 220 ° C. (screw tip) to form a film having a thickness of 150 μm.

<Raw Materials Used for Base Films of Examples / Comparative Examples>
・ Linear low density polyethylene 1
Product name: Evolue SP0540, manufactured by Prime Polymer Co., Ltd. Melting point 98 ° C. Molecular weight distribution ≦ 5 Metallocene catalyzed polyethylene ・ Low density polyethylene 1
Product name: Sumikasen L211, manufactured by Sumitomo Chemical Co., Ltd., melting point 113 ° C., molecular weight distribution> 5
・ Linear low density polyethylene 2
Product name: Evolue SP1540, manufactured by Prime Polymer Co., Ltd., melting point 113 ° C., molecular weight distribution ≦ 5, metallocene catalyzed polyethylene, low density polyethylene 2
Product name: Sumikasen L705, manufactured by Sumitomo Chemical Co., Ltd., melting point 107 ° C., molecular weight distribution> 5
・ Styrene-ethylene-butylene-styrene copolymer Product name: Septon 8007, manufactured by Kuraray Co., Ltd.

<3> Breaking energy After the substrate film is diced under the following dicing condition 1, the falling weight test is performed under the following falling weight test condition 1 from the back of the substrate to the intersection of the cut line cross with the cutting line down Then, the potential energy of the weight at which the base material breaks was measured and used as the breaking energy.

<Dicing condition 1>
Dicing blade: NBC-ZH2050-SE 27HEDD (manufactured by DISCO Corporation)
Blade rotation speed: 40000 rpm
Cutting speed: 100 mm / sec
Blade height: 80 μm
Sample cut size: 70mm x 60mm square 6 inch ring used

<Falling weight test condition 1>
Weight: 1.02 kg
Conical tip shape: Fixed shape of hemispherical test piece with a diameter of 20 mm: Circular shape with a diameter of 40 mm

<Preparation of adhesive layer>
A base resin having a weight average molecular weight of 150,000 was obtained by solution polymerization of 30% by weight of 2-ethylhexyl acrylate, 70% by weight of vinyl acetate and 1% by weight of 2-hydroxyethyl methacrylate in a toluene solvent. Addition of 100 parts by weight of bifunctional urethane acrylate as an energy ray curable resin (Mitsubishi Rayon Co., Ltd., weight average molecular weight of 11,000) and addition of polyhydric alcohol of tolylene diisocyanate as a crosslinking agent to 100 parts by weight of this base resin 15 parts by weight of a body (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) and 5 parts by weight of 2,2-dimethoxy-2-phenylacetophenone as an energy ray polymerization initiator were dissolved in ethyl acetate, and then a release-treated polyester film (thickness) The thickness after drying was 20 μm and dried at 80 ° C. for 5 minutes to obtain an adhesive layer.

<Production of dicing film>
The above-mentioned pressure-sensitive adhesive layer was laminated at 30 ° C. on the base film (thickness 150 μm) of each Example and Comparative Example using a laminating roll to obtain a dicing film.

The obtained dicing film was evaluated on the following items.
<1> Generated amount of base mustache The dicing film obtained as described above was attached to a silicon mirror wafer (attached to a mirror surface). After pasting, the substrate was left for 20 minutes, and dicing was performed under the following dicing condition 2. The dicing film after dicing was irradiated with UV under the following UV irradiation condition 1, the silicon mirror wafer was peeled off, and the dicing line was observed with a microscope. Chips (base beards) on each side of a dicing line of arbitrary 10 chips (5 × 2 rows) were observed with a microscope (25 times). When the total number of substrate mustaches was 2 or less, ◎, 5 or less were ◯, 10 or less were Δ, 11 or more were x, and 5 or less were acceptable.

<Dicing condition 2>
Dicing blade: NBC-ZH2050-SE 27HEDD (manufactured by DISCO Corporation),
Blade rotation speed: 30000 rpm
Cutting speed: 50mm / sec
Sample cut size: 5mm x 5mm square blade height: 75μm
6 inch ring / semiconductor wafer (thickness: 400μ) used

<UV irradiation condition 1>
Illuminance: 65 mW / cm2
Integrated light quantity: 200 mJ / cm2
UV lamp: High-pressure mercury lamp H03-L21 80 W / cm
(Made by Eye Graphics Co., Ltd.)
UV illuminance meter: UV-PFA1 (made by Eye Graphics Co., Ltd.)

<2> Expandability Using the dicing film produced under the above conditions, dicing was performed under the following dicing conditions 3. Then, after UV irradiation under the following UV irradiation condition 2, the expansion was carried out under the following expanding conditions. The case where the tape did not break was marked with ◯, and the case where the tape was broken was marked with x.

<Dicing condition 3>
Dicing blade: NBC-ZH2050-SE 27HEDD (manufactured by DISCO Corporation)
Blade rotation speed: 30000 rpm
Cutting speed: 50 mm / sec
Sample cut size: 5 mm x 5 mm square blade height: 75 μm
6 inch ring / semiconductor wafer (thickness: 400μ) used

<UV irradiation condition 2>
Illuminance: 65 mW / cm2
Integrated light quantity: 200 mJ / cm2
UV lamp: High-pressure mercury lamp H03-L21 80 W / cm
(Made by Eye Graphics Co., Ltd.)
UV illuminance meter: UV-PFA1 (made by Eye Graphics Co., Ltd.)

<Expanding conditions>
Expanding amount: 5 mm
8-inch ring used

  The evaluation results of the above examples and comparative examples are shown in Table 1. In Examples 1 and 2 having the constitutional requirements defined in the present invention, generation of base whiskers was suppressed, and the expandability of the base film was also good. On the other hand, Comparative Examples 1 and 5 were inferior in expandability, as well as the occurrence of substrate mustache. In Comparative Examples 2, 3, 4, and 6, it was impossible to suppress the occurrence of substrate whiskers.

  Since the dicing film of the present invention has less generation of chips and substrate whiskers during dicing and has a suitable strength and good appearance as a dicing film, it is suitably used as a film for fixing a semiconductor member in a dicing process of manufacturing a semiconductor device. be able to.

DESCRIPTION OF SYMBOLS 1 ... Base film 2 ... Adhesive layer 3 ... Cut 10 ... Dicing film

Claims (6)

A dicing film having an adhesive layer on at least one surface of a base film, wherein the base film has a melting point of 110 ° C. or lower and a molecular weight distribution represented by weight average molecular weight / number average molecular weight of 5 or lower. A dicing film containing a certain polyethylene (A) and a styrene-based elastomer (B). The dicing film according to claim 1, wherein the polyethylene (A) is a linear low density polyethylene. The dicing film according to claim 1 or 2, wherein the polyethylene (A) is a linear low density polyethylene polymerized with a metallocene catalyst. The dicing film according to any one of claims 1 to 3, wherein the styrene-based elastomer (B) is a styrene-ethylene-butylene-styrene copolymer. The dicing according to any one of claims 1 to 4, wherein a weight ratio (A / B) of polyethylene (A) and styrene elastomer (B) in the base film is 30/70 or more and 70/30 or less. the film. The dicing film according to any one of claims 1 to 5, wherein the breaking energy of the substrate in the following breaking energy evaluation test is 15 mJ or more.
<Break energy evaluation test>
A cross cut is made on one side of the film under the following cut preparation conditions.
With the face where the cut was made facing down, with the following drop weight test conditions for the intersection of the cross cut,
A falling weight test is performed, and the potential energy at which the base material breaks is defined as the breaking energy.
<Cut cutting conditions>
Using a blade, a cut having a depth of 80 μm and a length of 40 mm or more is made into a cross.
<Falling weight test conditions>
Weight: 1.02 kg
Conical tip shape: Fixed shape of hemispherical test piece with a diameter of 20 mm: Circular shape with a diameter of 40 mm