JP2014200949A - Expandable film, and method for producing semiconductor device by using the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expandable film which is useful for, for example, laser dicing and has high transparency.SOLUTION: The expandable film includes a base material layer 13 having 80-1,000 MPa tensile modulus and a low friction layer 11. The low friction layer comprises a resin composition containing: 100 pts. mass of one or more resins selected from the group consisting of thermoplastic resins and thermosetting resins; and 0.01-10,000 pts. mass of silylated polyolefin obtained by a reaction of a silicon-containing compound, which has the structural unit shown by -Si(R)H-Y- (in which Ris a hydrogen atom, a halogen atom or a hydrocarbon group; Yis O, S or NR(Ris a hydrogen atom or a hydrocarbon group), with vinyl group-containing polyolefin having 100-500,000 number-average molecular weight to be measured by a GPC method. The expandable film has 9% or lower haze.

Description

  The present invention relates to an expandable film and a method for manufacturing a semiconductor device using the expandable film.

  In the manufacturing process of a semiconductor device, a semiconductor wafer on which a predetermined circuit pattern is formed is cut and separated (diced) into element pieces. At that time, a method is generally employed in which a semiconductor wafer is attached to a dicing film, the semiconductor wafer is cut into small pieces, and then the dicing film is stretched both vertically and horizontally to increase the interval between elements (see FIG. (See Patent Document 1).

  Examples of the dicing film include a dicing film (for example, Patent Document 2) including an expandable substrate layer made of a terpolymer (ionomer) containing ethylene, acrylic acid, and alkyl acrylate as a constituent component; A dicing film including a layer and a low friction layer has been proposed (for example, Patent Document 3). The low friction layer is supposed to contain polyethylene and a lubricant such as silicone oil.

  By the way, dicing is generally performed by rotating round blades (blade dicing). In recent years, dicing by laser light absorption ablation (laser dicing) has attracted attention because it is less damaged by heat and the like than blade dicing and can perform high-definition processing. For example, it has been studied that a workpiece is supported and fixed on a dicing film and the workpiece is diced with a laser beam (see Patent Document 4).

  In laser dicing, after a dicing film is attached to one surface of a semiconductor wafer, laser light may be irradiated through the dicing film. The dicing film used in such a manner is required to have high transparency.

  On the other hand, a resin composition containing a silylated polyolefin is known as a resin composition constituting a molded article having scratch resistance such as an automobile interior part (for example, Patent Document 5).

JP-A-2-215528 Japanese Patent No. 3845129 International Publication No. 2012/042869 JP 2002-343747 A International Publication No. 2012/098865

  However, the dicing film of Patent Document 2 has a concern that foreign matters derived from the polymerization method remain on the dicing film. Such a foreign substance easily scatters laser light and does not have sufficient transparency. Further, the dicing film of Patent Document 3 is desired to have higher transparency in order to increase the irradiation accuracy of laser light.

  That is, the low friction layer contained in the dicing film of Patent Document 3 imparts good slipperiness to the surface of the dicing film. Usually, a resin such as polyethylene or ethylene ionomer resin and a lubricant such as silicone oil are used. It can be a mixture with. However, the resin and the lubricant may not be sufficiently compatible with each other, which may reduce the transparency of the low friction layer and the expandable film including the low friction layer.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a highly transparent expandable film useful for, for example, laser dicing.

（式（１）中、
Ｒ^１は、水素原子、ハロゲン原子または炭化水素基であり；
Ｙ^１は、Ｏ、ＳまたはＮＲ^３０（Ｒ^３０は、水素原子または炭化水素基）である）
［２］ 前記樹脂組成物に含まれる前記樹脂は、ポリオレフィンである、［１］に記載の拡張性フィルム。
［３］ 前記基材層が、降伏点を有さないか、あるいは降伏点における伸度が１６％以上である、［１］または［２］に記載の拡張性フィルム。
［４］ 前記ケイ素含有化合物が、下記式（２）で表される構造を有する、［１］〜［３］のいずれかに記載の拡張性フィルム。

（式（２）中、
Ｒ^２１およびＲ^２３は、それぞれ独立して水素原子、ハロゲン原子または炭化水素基であり；
Ｙ^２１およびＹ^２２は、それぞれ独立してＯ、ＳまたはＮＲ^３０（Ｒ^３０は、水素原子または炭化水素基）であり；
ｍおよびｎは、それぞれ独立して０または１であり；
Ｒ^２１、Ｒ^２３、Ｙ^２１およびＹ^２２は、互いに同一であっても異なっていてもよく；
Ｒ^２２およびＲ^２４は、それぞれ独立してハロゲン原子または炭化水素基であり；
Ｚは、下記式（３）で表される２価の基であり；

（式（３）中、
Ｒ^２５およびＲ^２６は、それぞれ独立して水素原子、ハロゲン原子または炭化水素基であり；
Ｙ^２３は、それぞれ独立してＯ、ＳまたはＮＲ^３０（Ｒ^３０は、水素原子または炭化水素基）であり；
ｌは、０〜１００００の整数であり；
前記式（２）においてｍ＝ｎ＝０である場合、式（３）における複数のＲ^２５およびＲ^２６の少なくとも一つは水素原子である））
［５］ 前記式（２）のＲ^２１、Ｒ^２３、前記式（３）のＲ^２５およびＲ^２６は、いずれも炭化水素基である、［４］に記載の拡張性フィルム。
［６］ 前記ケイ素含有化合物が、ケイ素原子を３以上含有する、［１］〜［５］のいずれかに記載の拡張性フィルム。
［７］ 前記ビニル基含有ポリオレフィンが、下記式（４）で表される構造を有する、［１］〜［６］のいずれかに記載の拡張性フィルム。

（式（４）中、Ａは、炭素数２〜５０のα−オレフィンを含むモノマーの重合鎖である）
［８］ 前記式（４）のＡが、エチレンの単独重合鎖である、［７］に記載の拡張性フィルム。
［９］ 前記樹脂組成物に含まれる前記樹脂は、ポリエチレンである、［１］〜［８］のいずれかに記載の拡張性フィルム。
［１０］ 前記基材層は、２３℃における引張弾性率が１００〜５００ＭＰａである１−ブテン・α−オレフィン共重合体（Ａ）と、プロピレン・α−オレフィン共重合体（ｂ１）を含み、２３℃における引張弾性率が８〜５００ＭＰａであるプロピレン系エラストマー組成物（Ｂ）とを含み、前記（Ｂ）の含有量は、（Ａ）と（Ｂ）の合計１００重量部に対して３０〜７０重量部である、［１］〜［９］のいずれかに記載の拡張性フィルム。
［１１］ 前記プロピレン系エラストマー組成物（Ｂ）は、２３℃における引張弾性率が１０〜５０ＭＰａである、［１０］に記載の拡張性フィルム。
［１２］ 前記プロピレン系エラストマー組成物（Ｂ）は、１００重量部の前記プロピレン系エラストマー組成物（Ｂ）に対して１〜７０重量部のポリプロピレン（ｂ２）をさらに含む、［１０］または［１１］に記載の拡張性フィルム。
［１３］ 前記基材層の、前記低摩擦層が配置される面とは反対側の面であり、かつ前記拡張性フィルムの最表面に設けられた粘着剤層をさらに有し、前記粘着剤層の、ＳＵＳ−３０４−ＢＡ板の表面に貼着されて６０分間放置した後、前記ＳＵＳ−３０４−ＢＡ板の表面から剥離されるときの、ＪＩＳ Ｚ０２３７に準拠して測定される粘着力が０．１〜１０Ｎ／２５ｍｍである、［１］〜［１２］のいずれか一項に記載の拡張性フィルム。
［１４］ 前記基材層と前記粘着剤層との間に中間層をさらに含み、前記中間層は、２５℃における引張弾性率Ｅ（２５）および６０℃における引張弾性率Ｅ（６０）が、Ｅ（６０）／Ｅ（２５）＜０．１の関係を満たし、かつ前記２５℃における引張弾性率Ｅ（２５）が１〜１０ＭＰａである、［１３］に記載の拡張性フィルム。
［１５］ 前記中間層が、密度が８００〜８９０ｋｇ／ｍ^３のオレフィン系共重合体を含む、［１４］に記載の拡張性フィルム。
［１６］ 半導体ウエハに、［１］〜［１５］のいずれかに記載の拡張性フィルムを、前記拡張性フィルムの低摩擦層が設けられた面とは反対側の面を介して貼り付ける工程と、前記半導体ウエハをダイシングして半導体チップを得る工程と、前記拡張性フィルムを拡張して、前記半導体チップをピックアップする工程とを含む、半導体装置の製造方法。
［１７］ 前記ダイシングは、レーザー光を、前記拡張性フィルムを介して前記半導体ウエハに照射して行う、［１６］に記載の半導体装置の製造方法。 [1] An expandable film including a base material layer having a tensile modulus of 80 to 1000 MPa and a low friction layer, wherein the low friction layer is selected from the group consisting of a thermoplastic resin and a thermosetting resin. Reaction of 100 parts by mass of one or more resins, a silicon-containing compound having a structural unit represented by the following formula (1), and a vinyl group-containing polyolefin having a number average molecular weight of 100 to 500,000 as measured by GPC method A silylated polyolefin obtained by the reaction (however, a silylated polyolefin obtained by reaction of a silicon-containing compound having two or more SiH groups in one molecule and a vinyl group-containing compound having two or more vinyl groups in one molecule) Excluded) An expandable film comprising a resin composition containing 0.01 to 10,000 parts by mass, wherein the expandable film has a haze of 9% or less.

(In the formula (1),
R ¹ is a hydrogen atom, a halogen atom or a hydrocarbon group;
Y ¹ is O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group)
[2] The expandable film according to [1], wherein the resin contained in the resin composition is a polyolefin.
[3] The expandable film according to [1] or [2], wherein the base material layer does not have a yield point, or the elongation at the yield point is 16% or more.
[4] The expandable film according to any one of [1] to [3], wherein the silicon-containing compound has a structure represented by the following formula (2).

(In the formula (2),
R ²¹ and R ²³ are each independently a hydrogen atom, a halogen atom or a hydrocarbon group;
Y ²¹ and Y ²² are each independently O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group);
m and n are each independently 0 or 1;
R ²¹ , R ²³ , Y ²¹ and Y ²² may be the same or different from each other;
R ²² and R ²⁴ are each independently a halogen atom or a hydrocarbon group;
Z is a divalent group represented by the following formula (3);

(In formula (3),
R ²⁵ and R ²⁶ are each independently a hydrogen atom, a halogen atom or a hydrocarbon group;
Y ²³ is each independently O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group);
l is an integer from 0 to 10,000;
In the formula (2), when m = n = 0, at least one of the plurality of R ²⁵ and R ²⁶ in the formula (3) is a hydrogen atom))
[5] The expandable film according to [4], wherein R ²¹ and R ^{23 in} the formula (2) and R ²⁵ and R ^{26 in} the formula (3) are all hydrocarbon groups.
[6] The expandable film according to any one of [1] to [5], wherein the silicon-containing compound contains 3 or more silicon atoms.
[7] The expandable film according to any one of [1] to [6], wherein the vinyl group-containing polyolefin has a structure represented by the following formula (4).

(In Formula (4), A is a polymer chain of a monomer containing an α-olefin having 2 to 50 carbon atoms)
[8] The expandable film according to [7], wherein A in the formula (4) is an ethylene homopolymer chain.
[9] The expandable film according to any one of [1] to [8], wherein the resin contained in the resin composition is polyethylene.
[10] The base material layer includes a 1-butene / α-olefin copolymer (A) having a tensile elastic modulus at 23 ° C. of 100 to 500 MPa, and a propylene / α-olefin copolymer (b1), And a propylene-based elastomer composition (B) having a tensile modulus at 23 ° C. of 8 to 500 MPa, and the content of (B) is 30 to 100 parts by weight in total of (A) and (B). The expandable film according to any one of [1] to [9], which is 70 parts by weight.
[11] The expandable film according to [10], wherein the propylene-based elastomer composition (B) has a tensile elastic modulus at 23 ° C. of 10 to 50 MPa.
[12] The propylene-based elastomer composition (B) further includes 1 to 70 parts by weight of polypropylene (b2) with respect to 100 parts by weight of the propylene-based elastomer composition (B). ] The expandable film as described in.
[13] The pressure-sensitive adhesive layer further includes a pressure-sensitive adhesive layer provided on the outermost surface of the expandable film, the surface being the surface opposite to the surface on which the low friction layer is disposed. The adhesive strength measured according to JIS Z0237 when the layer is peeled off from the surface of the SUS-304-BA plate after being stuck on the surface of the SUS-304-BA plate for 60 minutes. The expandable film according to any one of [1] to [12], which is 0.1 to 10 N / 25 mm.
[14] The intermediate layer further includes an intermediate layer between the base material layer and the pressure-sensitive adhesive layer, and the intermediate layer has a tensile elastic modulus E (25) at 25 ° C and a tensile elastic modulus E (60) at 60 ° C. The expandable film according to [13], which satisfies a relationship of E (60) / E (25) <0.1 and has a tensile elastic modulus E (25) at 25 ° C. of 1 to 10 MPa.
[15] The expandable film according to [14], wherein the intermediate layer includes an olefin-based copolymer having a density of 800 to 890 kg / m ³ .
[16] A step of attaching the expandable film according to any one of [1] to [15] to a semiconductor wafer via a surface opposite to the surface on which the low friction layer of the expandable film is provided. And a step of dicing the semiconductor wafer to obtain a semiconductor chip, and a step of expanding the expandable film and picking up the semiconductor chip.
[17] The semiconductor device manufacturing method according to [16], wherein the dicing is performed by irradiating the semiconductor wafer with a laser beam through the expandable film.

  According to the present invention, a highly transparent expandable film can be provided. Such an expandable film is useful for laser dicing, for example.

FIG. 1 is a cross-sectional view showing a preferred example of the layer structure of the expandable film. It is a schematic diagram which shows an example of the manufacturing method of the semiconductor device using the dicing film of this invention. It is a schematic diagram which shows an example of the manufacturing method of the semiconductor device using the dicing film of this invention. It is a schematic diagram which shows an example of the manufacturing method of the semiconductor device using the dicing film of this invention. It is a schematic diagram which shows an example of the manufacturing method of the semiconductor device using the dicing film of this invention. It is a schematic diagram which shows an example of the manufacturing method of the semiconductor device using the dicing film of this invention. It is the top view and side view explaining the expansion test method of the expandable film in this example. It is a side view explaining the expansion test method of the expandable film in this example.

1. Expandable film The expandable film of the present invention includes at least a base material layer and a low friction layer; and may further include an adhesive layer and an intermediate layer as necessary.

About Base Material Layer The base material layer has a function of imparting expandability to the expandable film. Therefore, the base material layer preferably has good expandability, and the tensile elastic modulus at 25 ° C. of the base material layer is preferably 80 to 1000 MPa, and more preferably 100 to 800 MPa. From the same viewpoint, it is preferable that the stress-strain curve diagram at 25 ° C. obtained by the tensile test does not have a yield point or the elongation at the yield point is 16% or more. The elongation at the yield point is the amount of elongation of the test piece (the amount of deformation relative to the length of the sample piece before the tensile test) when the yield point is reached.

  Such a base material layer contains a thermoplastic resin as a main component. Although a thermoplastic resin will not be restrict | limited especially if the said physical property is satisfy | filled, Preferably it contains 1-butene and alpha-olefin copolymer (A) and a propylene-type elastomer composition (B).

1-butene / α-olefin copolymer (A)
The 1-butene / α-olefin copolymer (A) is a polymer containing 1-butene as a main constituent component. The α-olefin in the 1-butene / α-olefin copolymer (A) may be an α-olefin having 2 to 10 carbon atoms other than 1-butene. Examples of the α-olefin having 2 to 10 carbon atoms include ethylene, propylene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, preferably ethylene, Propylene. The α-olefin contained in the 1-butene / α-olefin copolymer (A) may be one kind or a combination of two or more kinds. The 1-butene content contained in the 1-butene / α-olefin copolymer (A) is preferably at least 80 mol%, more preferably at least 90 mol%. If it is less than 80 mol%, sufficient expandability cannot be obtained.

The density of the 1-butene / α-olefin copolymer (A) is not particularly limited, and can be, for example, about 890 to 950 kg / m ³ . If the density of the 1-butene / α-olefin copolymer (A) is too low, the tensile modulus of the base material layer containing the 1-butene / α-olefin copolymer (A) may be lowered, and sufficient expandability may not be obtained.

  The tensile elastic modulus at 23 ° C. of the film made of the 1-butene / α-olefin copolymer (A) is preferably 100 to 500 MPa, more preferably 150 to 450 MPa. If the tensile modulus of the film made of 1-butene / α-olefin copolymer (A) is too high, it will be too hard and difficult to expand; if the tensile modulus is too low, it will be too soft and handleability will be reduced. Cheap.

  The melt flow rate (MFR) of the 1-butene / α-olefin copolymer (A) measured at 230 ° C. under a load of 2.16 kg in accordance with ASTM D1238 is the propylene-based elastomer composition (B). From the viewpoint of facilitating uniform mixing in the extruder, it is preferably 1 to 20 g / 10 min, and more preferably 1 to 10 g / 10 min.

Propylene elastomer composition (B)
The propylene-based elastomer composition (B) contains a propylene / α-olefin copolymer (b1) as a main component, and preferably further contains polypropylene (b2).

  The propylene / α-olefin copolymer (b1) is a copolymer of propylene and an α-olefin other than propylene. The α-olefin in the propylene / α-olefin copolymer (b1) is preferably an α-olefin having 2 to 20 carbon atoms. Examples of the α-olefin having 2 to 20 carbon atoms include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene and 1-decene, preferably Ethylene, 1-butene. The α-olefin contained in the propylene / α-olefin copolymer (b1) may be one type or a combination of two or more types. The propylene / α-olefin copolymer (b1) is more preferably a propylene / 1-butene / ethylene copolymer.

  The content of the structural unit derived from propylene of the propylene / α-olefin copolymer (b1) is preferably 50 mol% or more, more preferably 60 mol% or more from the viewpoint of obtaining good rubber elasticity. .

  The propylene / α-olefin copolymer (b1) may have rubber elasticity at the handling temperature of the expandable film, and preferably has a glass transition point of 25 ° C. or lower. When the glass transition point exceeds 25 ° C., physical properties such as expandability of the film after molding may easily change depending on storage conditions.

  Polypropylene (b2) is essentially a homopolymer of propylene, but may contain a small amount of α-olefin other than propylene, so-called homopolypropylene (hPP), random polypropylene (rPP) and block polypropylene (bPP). Any of these may be used.

  The content of α-olefin other than propylene in the polypropylene (b2) is preferably 20 mol% or less, more preferably 10 mol% or less. Such polypropylene (b2) can be expected to have an effect of suppressing blocking of the propylene / α-olefin copolymer (b1) and an effect of improving film moldability.

  The content of polypropylene (b2) is preferably 1 to 70 parts by weight, more preferably 5 to 70 parts by weight, based on 100 parts by weight of the propylene-based elastomer composition (B), and 5 to 30 parts by weight. Part is more preferable, and 5 to 20 parts by weight is particularly preferable. When the content of polypropylene (b2) is less than 1 part by weight, the propylene / α-olefin copolymer (b1) may be blocked, and the extruded state may become unstable during film formation. If the content of polypropylene (b2) is more than 30 parts by weight, the expansion rate of the film may be small.

  The film consisting of the propylene-based elastomer composition (B) has a tensile modulus at 23 ° C. of preferably 8 to 500 MPa, more preferably 10 to 500 MPa, further preferably 10 to 100 MPa, and particularly preferably 10 to 50 MPa. 10 to 45 MPa is more preferable.

  The melt flow rate (MFR) of the propylene-based elastomer composition (B) measured at 230 ° C. and a load of 2.16 kg in accordance with ASTM D1238 is 1-butene / α-olefin copolymer (A). It may be in a range that is easily mixed uniformly in the extruder, preferably 1 to 20 g / 10 min, and more preferably 1 to 10 g / 10 min. If MFR is the said range, it will be easy to extrude to a uniform film thickness.

  The content of the propylene-based elastomer composition (B) in the base material layer is preferably 30 to 70 parts by weight, and 40 to 60 parts by weight with respect to 100 parts by weight in total of (A) and (B). It is more preferable that

  The base material layer can be formed by dry-blending or melt-blending the 1-butene / α-olefin copolymer (A) and the propylene-based elastomer composition (B), followed by extrusion. The base material layer thus obtained has a relatively high crystallinity and a high tensile elastic modulus, and a relatively low crystallinity and a low tensile elastic modulus. It has a structure in which the propylene-based elastomer composition (B) is finely dispersed.

  Specifically, in the cross-sectional TEM images of the base material layer in the MD direction and the TD direction, the bright portion (1-butene / α-olefin copolymer (A)) extending in the direction parallel to the base material layer surface is present. Seen. Such a phase separation structure can be observed as a “bright / dark structure” by a transmission electron microscope (TEM) image observed by slicing a cross section of the base material layer.

  The base material layer having such a structure has good expandability without causing necking. The reason is not necessarily clear, but is presumed as follows. That is, when stress is applied to the expandable film having the phase separation structure as described above, the 1-butene / α-olefin copolymer (A) is elastically deformed and before being necked, the propylene-based elastomer composition ( Through B), the stress applied to the 1-butene / α-olefin copolymer (A) is made uniform in the cross-sectional direction of the film. For this reason, it is considered that the higher-order structure of the 1-butene / α-olefin copolymer (A) isotropically deformed as a whole of the expandable film, and the range in which elastic deformation can occur without causing necking is expanded.

  The TEM observation of the base material layer was performed by cutting a sample piece having a thickness of 100 μm in a direction parallel to the MD direction and a direction parallel to the TD direction; the obtained cross-sections were respectively transmitted electron microscopes (TEM, H-7650 manufactured by Hitachi, Ltd.). Can be performed by observing at a magnification of 5000 to 20000 times.

  Although the thickness of a base material layer is not restrict | limited in particular, For example, when an expandable film is used as a dicing film, Preferably it is about 50-200 micrometers. The thickness of the base material layer can be about 1 to 10 times, preferably about 2 to 6 times the thickness of the low friction layer described later.

About the low friction layer The low friction layer has a function of imparting slipperiness to the surface of the expandable film. For example, when an expandable film is used as a dicing film, when the dicing film is expanded on the stage of the expander (see FIG. 2D described later), it is desirable that the slipperiness of the surface in contact with the film stage is high.

  In order to impart high slipperiness to the low friction layer, a lubricant such as silicone oil is generally mixed with the resin as the main component. However, if the compatibility between the resin and the lubricant is not sufficient, the transparency of the low friction layer and the expandable film containing it may be reduced. Such an expandable film may not be suitable as a dicing film for laser dicing that irradiates laser light through the film.

  On the other hand, in the present invention, by using “polyolefin containing a silicon-containing block” (silylated polyolefin), the compatibility between the resin and “resin containing a block comprising a silicon-containing skeleton” can be increased. It has been found that the transparency of the friction layer can be enhanced.

  That is, in the present invention, the low friction layer is made of a resin composition containing a resin as a main component and a silylated polyolefin.

Resin as the main component The resin as the main component can be a thermoplastic resin or a thermosetting resin. The thermoplastic resin may be a polyolefin resin, a polycarbonate resin, a thermoplastic polyester resin, an ABS resin, a polyacetal resin, a polyamide resin, a polyphenylene oxide resin, a polyimide resin, a polyurethane resin, a polylactic acid resin, or the like. The thermosetting resin may be a resin in which a part of the thermoplastic resin is modified with a compound containing a curable group. These may be used alone or in combination of two or more. Among these, a thermoplastic resin is preferable, and a polyolefin resin is preferable because it is easily compatible with the base material layer and can be easily co-extruded.

  Examples of polyolefin resins include polyethylene resins such as low density polyethylene and high density polyethylene; polypropylene resins; ethylene / vinyl acetate copolymers, ethylene / methacrylic acid acrylate copolymers, and the like. Especially, since it is resin which is flexible and has a small environmental load, low density polyethylene and polypropylene resin are preferable, and low density polyethylene is more preferable.

The MFR of the polyolefin resin measured by a method in accordance with JIS K7210 is preferably 0.01 to 200 g / 10 minutes, at least in order to enable extrusion molding, and 0.01 to 100 g / 10 minutes. More preferably. The density of the polyolefin resin is preferably 900 to 950 kg / m ³ .

Silylated polyolefin (P)
Silylated polyolefin (P) is a compound obtained by reacting (addition polymerization) a silicon-containing compound and a vinyl group-containing polyolefin. That is, the silylated polyolefin can be a block copolymer including a block A derived from a silicon-containing compound and a block B derived from a vinyl group-containing polyolefin.

The silicon-containing compound for obtaining the silylated polyolefin (P) preferably contains a structural unit represented by the following formula (1).

R ^{1 in the} formula (1) is a hydrogen atom, a halogen atom or a hydrocarbon group, preferably a hydrocarbon group.

  The halogen atom is a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or the like, preferably fluorine or chlorine.

  The hydrocarbon group can be an alkyl group, an alkenyl group, an aryl group, and the like. The alkyl group is an alkyl group having 1 to 20 carbon atoms, preferably 1 to 3 carbon atoms; examples thereof include a methyl group and an ethyl group. An alkenyl group is an alkenyl group having 2 to 4 carbon atoms; examples include vinyl groups, propenyl groups, and the like. The aryl group is an aryl group having 6 to 20 carbon atoms, preferably 6 to 10 carbon atoms; examples thereof include a phenyl group, a tolyl group, a biphenyl group, a naphthyl group, and an anthryl group. Among these, an alkyl group is preferable.

Y ^{1 in the} formula (1) is O, S or NR ³⁰ and is preferably O. ^{R 30} in NR ³⁰ is a hydrogen atom or a hydrocarbon group. The hydrocarbon group can be defined in the same manner as the hydrocarbon group described above.

The silicon-containing compound preferably has a structure represented by the following formula (2).

R ²¹ and R ^{23 in} the formula (2) are each independently a hydrogen atom, a halogen atom or a hydrocarbon group, preferably a hydrocarbon group.

Y ²¹ and Y ^{22 in} the formula (2) are each independently O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group), and preferably O.

M and n in formula (2) may each independently be 0 or 1. Although m and n depend on the structure of the silylated polyolefin (P) to be obtained, it is preferable that m = n = 1 or m = 1 and n = 0. For example, if m = n = 1, a silylated polyolefin having a structure in which a block B derived from a vinyl group-containing polyolefin is bonded to both ends of a block A derived from a silicon-containing compound as described later can be obtained. R ²¹ , R ²³ , Y ²¹ and Y ²² may be the same as or different from each other.

R ²² and R ^{24 in} the formula (2) are each independently a halogen atom or a hydrocarbon group.

Z in the formula (2) is a divalent group represented by the following formula (3).

R ²⁵ and R ^{26 in} the formula (3) are each independently a hydrogen atom, a halogen atom or a hydrocarbon group, preferably a hydrocarbon group.

Y ^{23 in the} formula (3) is each independently O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group), preferably O.

L of Formula (3) is an integer of 0-10000, Preferably it is 0-1000. When m and n in the formula (2) are both 0, at least one of R ²⁵ and R ²⁶ in the formula (3) is a hydrogen atom.

  The halogen atom and hydrocarbon group in formulas (2) and (3) can be defined in the same manner as the halogen atom and hydrocarbon group in formula (1), respectively.

R ²¹ and R ^{23 in} the formula (2) and R ²⁵ and R ^{26 in} the formula (3) are all hydrocarbon groups because, for example, a linear silylated polyolefin is easily obtained as described later. Preferably there is an alkyl group.

  The number of silicon atoms contained in the silicon-containing compound is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more in one molecule. On the other hand, the number of silicon atoms contained in the silicon-containing compound is preferably 10,000 or less, more preferably 1000 or less, and even more preferably 300 or less.

Specific examples of the silicon-containing compound include the following. Examples of silicon-containing compounds having one SiH group include:

Examples of silicon-containing compounds having two or more SiH groups include the following.

  The vinyl group-containing polyolefin for obtaining the silylated polyolefin (P) is a polyolefin having at least one vinyl group in the molecule. The vinyl group is preferably present at the molecular end; more preferably only at the molecular end; particularly preferably only at one of the molecular ends. This is because a linear silylated polyolefin can be obtained by allowing the vinyl group to exist only at one of the molecular ends.

That is, the vinyl group-containing polyolefin preferably has a structure represented by the following formula (4).

  A in the formula (4) is a polymer chain of a monomer containing an α-olefin having 2 to 50 carbon atoms (preferably 2 to 20 carbon atoms). It is preferable that all the monomers constituting A are α-olefins having 2 to 50 carbon atoms.

  Examples of the α-olefin having 2 to 50 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, and 3-methyl. -1-pentene, 3,4-dimethyl-1-pentene, 4-methyl-1-hexene, 3-ethyl-1-pentene and the like are included, and ethylene and propylene are preferable. These may be used alone or in combination of two or more.

  These α-olefins can be appropriately selected according to the resin that is the main component of the low friction layer. For example, when the resin that is the main component of the low friction layer is polyethylene, in order to increase compatibility with the polyethylene, the α-olefin constituting A contains ethylene (A is an ethylene polymer chain). Are preferred).

  The ethylene polymer chain may be a homopolymer chain of ethylene or a copolymer chain of ethylene and other α-olefin.

  The number average molecular weight (Mn) measured by the GPC method of the vinyl group-containing polyolefin is preferably 100 or more and 500000 or less, more preferably 500 or more and 50000 or less, and further preferably 700 or more and 10,000 or less. . The molecular weight distribution (Mw / Mn) of the vinyl group-containing polyolefin is preferably 1.1 to 3.0.

The number average molecular weight (Mn) and the weight average molecular weight (Mw) can be measured by the following methods.
It measured using GIP-150 by Millipore. The separation column was TSK GNH HT, and the column size was 7.5 mm in diameter and 300 mm in length. The column temperature was 140 ° C., orthodichlorobenzene (manufactured by Wako Pharmaceutical Co., Ltd.) and 0.025% by mass of BHT (manufactured by Takeda Pharmaceutical Co., Ltd.) were used as the mobile phase, and the mobile phase was moved at 1.0 ml / min. The sample concentration was 0.1% by mass, and the sample injection amount was 500 microliters. A differential refractometer was used as a detector. A calibration curve was prepared using standard polystyrene and converted into a value in terms of polyethylene according to a conventional method.

  The melting point of the vinyl group-containing polyolefin is preferably 70 ° C. or higher and 130 ° C. or lower. The melting point can be measured by DSC-60A, the reference cell is alumina, and the temperature is increased from 30 ° C. to 300 ° C. at a temperature increase rate of 10 ° C./min.

The terminal unsaturated ratio (VE) of the vinyl group-containing polyolefin is preferably 60 mol% or more, more preferably 80 mol% or more, and still more preferably 90% or more. The terminal unsaturation rate (VE) is a ratio of the main chain terminal vinyl group to the total of the main chain terminal vinyl group and the terminal methyl group in the vinyl group-containing polyolefin, and can be measured by ¹ H-NMR.

  The vinyl group-containing polyolefin having a structure represented by the formula (4) can be synthesized by a known method. For example, an ethylene homopolymer chain in a vinyl group-containing polyethylene has a carbon number of 2 to 50, using a transition metal compound having a salicylaldoimine ligand as described in JP-A-2000-239312 as a polymerization catalyst. It can be obtained by polymerizing α-olefin.

  In the silylated polyolefin (P), the bonding mode of the block A derived from the silicon-containing compound and the block B derived from the vinyl group-containing polyolefin is not particularly limited, and the main chain end of the block A and the main chain end of the block B are bonded. The side chain end of block A and the main chain end of block B may be bonded; the side chain end of block A and the main chain end of block B may be bonded Good. Among these, in order to facilitate the molecular motion and to make the silylated polyolefin unevenly distributed on the surface of the molded product during molding of the resin composition containing the silylated polyolefin, the main chain terminal of the block A and the main chain terminal of the block B are used. Are preferably bonded to each other.

  The number p of the block A and the number q of the block B contained in the silylated polyolefin (P) are not particularly limited, but can be independently 1 to 10, preferably 1 or 2, more preferably p = 1 and q = 2.

  The molecular terminal of the silylated polyolefin (P) may be a block A derived from a silicon-containing compound or a block B derived from a vinyl group-containing polyolefin. In order to enhance compatibility with the resin that is the main component of the low friction layer, it is preferable that one or both of the molecular ends of the silylated polyolefin is a block B.

  That is, preferable examples of the bonding mode between the block A and the block B of the silylated polyolefin include block A-block B, block A-block B-block A, block B-block A-block B, etc. Block B-Block A-Block B.

  The content ratio of the block A derived from the silicon-containing compound in the silylated polyolefin (P) is usually preferably 5 to 99% by mass, more preferably 10 to 95% by mass, and 15 to 50% by mass. More preferably it is. The content ratio (mass ratio) of the block A derived from the silicon-containing compound in the silylated polyolefin (P) is defined as “silicone content”. When the block A derived from a silicon-containing compound includes a “group having an alkylene chain having 4 or more carbon atoms bonded to a Si atom”, in the calculation of the content ratio of the block A, the “number of carbon atoms bonded to the Si atom” “Groups having 4 or more alkylene chains” count as block B, not block A.

  When the content ratio of the block A derived from the silicon-containing compound is not less than a certain level, the slip-imparting effect of the silylated polyolefin can be enhanced. When the content ratio of the block A derived from the silicon-containing compound is below a certain level, compatibility with the silylated polyolefin resin can be ensured.

  The MFR of the silylated polyolefin (P) measured at 190 ° C. under a load of 2.16 kg in accordance with JIS K 7210 is preferably 0.01 g / 10 min or more, more preferably 0.1 g / 10 min or more. More preferably, it is 1 g / 10 min or more.

Examples of the silylated polyolefin (P) include the following.

  As described above, the silylated polyolefin (P) can be obtained by reacting (addition polymerization) a silicon-containing compound and a vinyl group-containing polyolefin. However, silylated polyolefin obtained by reaction of a silicon-containing compound having two or more SiH groups in one molecule and a vinyl group-containing polyolefin having two or more vinyl groups in one molecule is excluded. This is because such silylated polyolefin has a crosslinked structure and has low flexibility. Silylated polyolefin (P) is, for example, 1) a step of mixing and stirring a silicon-containing compound and a transition metal halide, and filtering the resulting suspension to obtain a transition metal catalyst composition (C); 2) It can be obtained through a step of obtaining a silylated polyolefin (P) by reacting a vinyl group-containing polyolefin with a silicon-containing compound in the presence of the obtained transition metal catalyst composition (C).

Step 1) First, a silicon-containing compound and a transition metal halide are mixed and stirred to obtain a suspension.

  The transition metal constituting the halogenated transition metal is a transition metal of Group 3 to Group 12 of the periodic table, preferably a transition metal of Groups 8 to 10 of the periodic table, more preferably platinum. is there. The halogen atom constituting the halogenated transition metal is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom.

  Specific examples of the halogenated transition metal include platinum dichloride, palladium dichloride, ruthenium trichloride, rhodium trichloride and iridium trichloride, preferably platinum dichloride. The transition metal halide is usually in the form of particles; its particle size is 1000 μm or less, preferably 500 μm or less.

  The mixing of the silicon-containing compound and the transition metal halide is performed by adding the silicon-containing compound and stirring the mixture after charging the halogenated transition metal in a reactor equipped with a stirrer under a nitrogen stream. Mixing and stirring is performed at 0 to 50 ° C, preferably 10 to 30 ° C.

  The mixing ratio of the silicon-containing compound and the transition metal halide can be set so that the amount of the silicon-containing compound is 1 equivalent or more, preferably 2 equivalents or more, relative to the amount of the transition metal halide.

  In mixing the silicon-containing compound and the transition metal halide, a solvent may be further used. Examples of the solvent used include toluene, xylene and the like.

  And the obtained suspension solution is filtered and solid content is removed, A transition metal catalyst composition (C) is obtained as a filtrate. The obtained transition metal catalyst composition (C) may contain a transition metal compound in the form of a nanocolloid, a silicon-containing compound, and a solvent as necessary. The transition metal catalyst composition (C) can be further concentrated or diluted as necessary.

Step 2) In the presence of the obtained transition metal catalyst composition (C), a vinyl group-containing polyolefin and a silicon-containing compound are reacted to obtain a silylated polyolefin (P).

  Specifically, the vinyl group-containing polyolefin is charged into the reactor, and the silicon-containing compound and the transition metal catalyst composition (C) are charged under a nitrogen atmosphere. The reactor is set in a hot water bath whose internal temperature has been raised above the melting point of the vinyl group-containing polyolefin in advance, and stirred. After the reaction, the reactor is removed from the hot water bath and cooled to room temperature, and the resulting reaction mixture is taken up in methanol or acetone and stirred for 2 hours. Thereafter, the obtained solid is collected by filtration, washed with a solvent, and then dried under reduced pressure at 60 ° C. and 2 hPa or less to obtain a silylated polyolefin (P).

  The amount ratio of the vinyl group-containing polyolefin and the silicon-containing compound varies depending on the purpose, but the ratio of the equivalent of the vinyl group in the vinyl group-containing polyolefin to the equivalent of the Si—H bond in the silicon-containing compound (Si—H (Equivalent of bond / equivalent of vinyl group) can be set to be 0.01 to 10, preferably 0.1 to 2. The equivalent of Si—H bonds in the silicon-containing compound is added in the step of 2) with the equivalent of Si—H bonds in the silicon-containing compound contained in the transition metal catalyst composition (C) in the step 1). Is the sum of equivalents of Si-H bonds in the silicon-containing compound.

The quantitative ratio of the transition metal catalyst composition (C) to the vinyl group-containing polyolefin is, for example, the ratio of the equivalent of transition metal in the transition metal catalyst composition (C) to the equivalent of vinyl group in the vinyl group-containing polyolefin ( (Equivalent of vinyl group / equivalent of transition metal) is 10 ⁻¹⁰ to 10 ⁻¹ , preferably 10 ⁻⁷ to 10 ⁻³ .

  The reaction temperature between the vinyl group-containing polyolefin and the silicon-containing compound is preferably 100 to 200 ° C.

  The silylated polyolefin (P) thus obtained has a block B derived from a vinyl group-containing polyolefin. Therefore, good slipperiness by the block A derived from the silicon-containing compound can be expressed while being well compatible with the resin that is the main component of the low friction layer.

  Furthermore, the structure of silylated polyolefin (P) is a linear structure having no graft structure (branched structure); preferably a structure of block B-block A-block B, which facilitates molecular motion during molding. And it can make it easy to make uneven distribution on the surface of the obtained low friction layer.

  The content of the silylated polyolefin (P) in the resin composition constituting the low friction layer is preferably 0.01 to 10,000 parts by mass with respect to 100 parts by mass of the resin as the main component. By making the content rate of silylated polyolefin (P) more than fixed, it is easy to give sufficient slipperiness to a low friction layer. By making the content rate of silylated polyolefin (P) below a certain level, the haze fall of a low friction layer can be suppressed more highly.

  In addition to the resin as the main component and the silylated polyolefin (P), other components may be further included as necessary.

  The thickness of the low friction layer is not particularly limited, but is preferably 1 to 30 μm, for example, and more preferably 5 to 20 μm.

  The film having a thickness of 10 μm made of the resin composition constituting the low friction layer preferably has a haze of less than 5%, more preferably 4% or less. When the haze of the low friction layer is below a certain level, the transparency of the expandable film including the haze can be sufficiently increased. Haze can be measured by a haze meter NDH5000.

  In order to reduce the haze of the low friction layer, for example, the content of the silylated polyolefin (P) in the resin composition is reduced; the content ratio of the block B derived from the vinyl group-containing polyolefin in the silylated polyolefin (P) Or more.

  The tensile elastic modulus of a film having a thickness of 100 μm made of the resin composition constituting the low friction layer is preferably 600 MPa or less, and more preferably 500 MPa or less, from the viewpoint of enhancing expandability.

The tensile modulus of the film made of the resin composition can be measured by the following method.
1) As a measurement sample, for example, a sample film having an initial length of 140 mm, a width of 10 mm, and a thickness of 75 to 100 μm is prepared.
2) Then, a tensile test is performed at a measurement temperature of 25 ° C., a distance between chucks of 100 mm, and a tensile speed of 50 mm / min, and the amount of change (mm) in elongation of the sample is measured.
3) A tangent is drawn to the initial rising portion of the obtained SS curve (stress-strain curve), and the value obtained by dividing the slope of the tangent by the cross-sectional area of the sample film is taken as the tensile modulus.

  In order to reduce the tensile elastic modulus of the resin composition, for example, the content of the silylated polyolefin (P) in the resin composition is increased, or the block A derived from the silicon-containing compound in the silylated polyolefin (P). It is better to increase the content ratio.

  In order to enable molding of the base material layer and the low friction layer by coextrusion, the resin composition constituting the low friction layer is measured at a temperature of 230 ° C. and a load of 2.16 kg in accordance with ASTM D1238. The MFR may be the same as that of the above-described base material layer. The difference between the MFR of the resin composition that constitutes the low friction layer and the MFR of the resin composition that constitutes the base material layer is preferably not more than a certain value, and can be, for example, 5 g / 10 min or less.

About the intermediate layer The intermediate layer has a function of absorbing irregularities on the surface of the semiconductor wafer. As will be described later, the intermediate layer may be, for example, a layer provided between the base material layer and the pressure-sensitive adhesive layer, or may be a layer having the function of the pressure-sensitive adhesive layer.

  The intermediate layer preferably has a tensile elastic modulus E (25) at 25 ° C. and a tensile elastic modulus E (60) at 60 ° C. satisfying E (60) / E (25) <0.1, particularly E (60 ) / E (25) <0.08 is more preferable, and E (60) / E (25) <0.05 is more preferable.

  When the ratio of the tensile modulus at 25 ° C. and 60 ° C. satisfies the above range, the intermediate layer has heat melting properties and can be plastically deformed. Specifically, when the expandable film is attached to a semiconductor wafer under heating, high adhesion tends to be obtained following the unevenness of the circuit formation surface of the semiconductor wafer.

  The intermediate layer has a tensile modulus E (25) at 25 ° C. of 1 MPa to 10 MPa, and more preferably 2 MPa to 9 MPa. If the tensile modulus E (25) is in the above range, the shape at room temperature after the expandable film is attached can be maintained, and the adhesion during processing can be maintained.

  The tensile elastic modulus E (60) at 60 ° C. of the intermediate layer is preferably 0.005 MPa to 1.0 MPa, and more preferably 0.01 MPa to 0.5 MPa. If the tensile elastic modulus E (60) is in the above range, when the expandable film is attached under heating, fluidity is exhibited, and therefore good followability to unevenness can be obtained. The tensile modulus of the resin can be measured by the same method as described above.

The density of the resin constituting the intermediate layer is preferably ^{800~890kg / m 3, 850~890kg / m} 3 and more preferably. If the density of the resin constituting the intermediate layer is less than 800 kg / m ³ , the elastic modulus becomes too low, and the shape fixing force tends to be reduced. On the other hand, when the density of the resin constituting the intermediate layer exceeds 890 kg / m ³ , the elastic modulus becomes too high, and the followability to unevenness tends to be lowered.

  The resin constituting the intermediate layer only needs to satisfy the tensile elastic modulus, and is preferably an olefin copolymer. The olefin copolymer is preferably an α-olefin copolymer having an α-olefin having 2 to 12 carbon atoms as a main structural unit. Examples of the α-olefin having 2 to 12 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene and the like.

  Among these, ethylene / propylene copolymer, ethylene / 1-butene copolymer, and the like are preferable, and ethylene / propylene copolymer is more preferable in terms of excellent uneven conformability at the time of pasting. This is because propylene has high heat-meltability among olefin copolymers. Commercially available α-olefin copolymers include TAFMER (registered trademark) manufactured by Mitsui Chemicals.

  The tensile elastic modulus of the intermediate layer is adjusted by the type of monomer constituting the olefin copolymer, the copolymerization ratio, the presence or absence of modification, and the like. For example, in order to lower the tensile elastic modulus of an olefin copolymer at 60 ° C., the copolymerization ratio of propylene may be increased or modified with carboxylic acid or the like.

  The intermediate layer may contain other resins or other additives within a range that does not impair easy pastability and easy peelability to the semiconductor wafer. Examples of such additives include ultraviolet absorbers, antioxidants, heat stabilizers, softeners, tackifiers and the like.

  The thickness of the intermediate layer is preferably larger than the step provided on one surface of the wafer to which the dicing film is bonded, and this step (for example, unevenness (including solder bumps) on the circuit forming surface of the semiconductor wafer) is embedded. If it is the thickness which can do, it will not restrict | limit in particular. For example, if the uneven step is about 100 μm, the thickness of the intermediate layer can be 100 to 300 μm. That is, the thickness of the intermediate layer is preferably 1 to 3 times, more preferably 1 to 2 times the level difference on the wafer surface.

About the pressure-sensitive adhesive layer The pressure-sensitive adhesive layer may be composed of a known pressure-sensitive adhesive, and is not particularly limited. For example, in addition to pressure-sensitive adhesives such as rubber, acrylic and silicone, thermoplastics such as styrene-based elastomers and olefin-based elastomers. It can be composed of an elastomer.

  The acrylic pressure-sensitive adhesive may be a homopolymer of an acrylate compound or a copolymer of an acrylate compound and a comonomer. Examples of the acrylate compound include methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate. Examples of comonomer constituting the acrylic copolymer include vinyl acetate, acrylonitrile, acrylamide, styrene, methyl (meth) acrylate, (meth) acrylic acid, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, glycidyl methacrylate and anhydrous Maleic acid and the like are included.

  The pressure-sensitive adhesive layer may be composed of a radiation curable pressure-sensitive adhesive that reduces the pressure-sensitive adhesive force by radiation, a heat-curable pressure-sensitive adhesive that decreases the pressure-sensitive adhesive force by heating, or the like. A preferable example of the radiation curable pressure sensitive adhesive includes an ultraviolet curable pressure sensitive adhesive.

  The ultraviolet curable pressure-sensitive adhesive and the heat-curable pressure-sensitive adhesive include a pressure-sensitive adhesive such as the acrylic pressure-sensitive adhesive and a photopolymerization initiator or a thermal polymerization initiator, and a curable compound (carbon-carbon double) as necessary. A component having a bond) and a cross-linking agent.

  The photopolymerization initiator may be any compound that can be cleaved by irradiation with ultraviolet rays to generate radicals. For example, benzoin alkyl ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; -Aromatic ketones such as hydroxycyclohexyl phenyl ketone; aromatic ketals such as benzyldimethyl ketal;

  The thermal polymerization initiator is an organic peroxide derivative or an azo polymerization initiator, and is preferably an organic peroxide derivative from the point that nitrogen is not generated during heating. Examples of the organic peroxide derivative include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide and the like.

  The curable compound may be any monomer, oligomer or polymer having a carbon-carbon double bond in the molecule and curable by radical polymerization. Examples of such curable compounds include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neo Examples include esters of (meth) acrylic acid and polyhydric alcohols such as pentyl glycol di (meth) acrylate and dipentaerythritol hexa (meth) acrylate. When the pressure-sensitive adhesive is an ultraviolet curable polymer having a carbon-carbon double bond in the side chain, it is not always necessary to add a curable compound.

  The content of the curable compound is preferably 5 to 900 parts by weight with respect to 100 parts by weight of the pressure-sensitive adhesive, and more preferably 20 to 200 parts by weight. When there is too little content of a sclerosing | hardenable compound, there will be too few parts to harden | cure and adjustment of adhesive force will become inadequate. When there is too much content of a sclerosing | hardenable compound, the sensitivity with respect to a heat | fever or light is too high, and storage stability falls.

  Examples of the crosslinking agent include epoxy compounds such as pentaerythritol polyglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate and polyisocyanate.

  Adhesive strength measured in accordance with JIS Z0237 when peeling from the surface of the SUS-304-BA plate after the pressure-sensitive adhesive layer is adhered to the surface of the SUS-304-BA plate and left standing for 60 minutes. It is preferable that it is 0.1-10N / 25mm. If the adhesive strength is in the above range, it is possible to suppress the adhesive residue when the chip is peeled off while ensuring good adhesion to the wafer. The adhesive strength of the pressure-sensitive adhesive layer can be adjusted by, for example, the amount of crosslinking agent added. Specifically, it can be adjusted by the method described in JP-A No. 2004-155591.

  The thickness of an adhesive layer should just be a range which does not inhibit the expansibility of the above-mentioned base material layer, and can be normally 1-50 micrometers, Preferably it is 1-25 micrometers.

Regarding the layer structure: The expandable film includes a base material layer and a low friction layer; from the viewpoint of obtaining good adhesion to a semiconductor wafer, it is preferable that the expandable film further includes one or both of an adhesive layer and an intermediate layer; It is more preferable to further include both an adhesive layer and an intermediate layer.

  An adhesive layer and an intermediate | middle layer are arrange | positioned at the surface on the opposite side to the surface in which a low friction layer is provided of a base material layer. The pressure-sensitive adhesive layer is disposed on the outermost surface of the expandable film. When the expandable film includes both the pressure-sensitive adhesive layer and the intermediate layer, the intermediate layer can be disposed between the base material layer and the pressure-sensitive adhesive layer. Layers other than those described above may be further disposed between the layers. A plurality of each layer may be provided.

  FIG. 1 is a cross-sectional view showing a preferred example of the layer structure of the expandable film. As shown in FIG. 1, the expandable film 10 includes a low friction layer 11, a base material layer 13, an intermediate layer 15, and an adhesive layer 17 in this order.

  The thickness of the expandable film is preferably 50 to 200 μm, for example, and more preferably 70 to 170 μm.

  As will be described later, the haze of the expandable film is preferably 9% or less so as to be applicable to laser dicing or the like in which laser light is irradiated through the expandable film. The haze is preferably a haze having a thickness of 150 μm. Haze can be measured by the same method as described above.

  The haze of the expandable film can be adjusted preferably by the haze of the low friction layer, the thickness of the expandable film, or the like.

2. Method for producing expandable film The expandable film of the present invention can be produced by any method. For example, in addition to a base material layer and a low friction layer, an expandable film including a pressure-sensitive adhesive layer and an intermediate layer is 1) a method of co-extrusion of molten resin constituting each layer (co-extrusion method); 2) A method of laminating a molten resin constituting another layer on the base material layer (extrusion laminating method); 3) a method of laminating a film constituting each layer via thermocompression bonding or an adhesive (lamination method); and 4) It can be produced by a method (coating method) of applying and laminating a resin composition constituting the pressure-sensitive adhesive layer on a base material layer or a laminate in which a base material layer and an intermediate layer are laminated.

  The melt kneading temperature may be a temperature suitable for melting and kneading the resin constituting each layer, and the melting temperature of the resin constituting the base material layer may be, for example, 180 to 260 ° C. The extrusion method is not particularly limited, and may be an inflation extrusion method, a T-die extrusion method, or the like.

  Similarly, the resin composition constituting the base material layer and the resin composition constituting the low friction layer are coextruded, or the resin composition constituting the low friction layer is extrusion laminated on the base material layer. In order to obtain an expandable film, the MFR at 230 ° C. of the base material layer and the MFR at 230 ° C. of the low friction layer, both measured in accordance with ASTM D1238, are 1 to 20 g / 10 min or less. It is preferable that By having such an MFR, each layer can be molded with a stable film thickness.

  In addition, when the composition for adhesive layers has radiation curability, the method of drying after apply | coating directly on a base material layer or on the laminated body of a base material layer and an intermediate | middle layer (the above-mentioned coating method) is preferable. . The laminate of the base material layer and the intermediate layer is obtained by coextruding the resin composition constituting the base material layer and the resin composition constituting the intermediate layer; the resin constituting the intermediate layer on the base material layer The composition can be obtained by extrusion lamination.

  The low friction layer of the expandable film of the present invention thus obtained has high transparency because the resin as the main component and the silylated polyolefin are well compatible. Thereby, the expandable film of the present invention also has high transparency.

  Moreover, the expansible film of this invention can also have high expansibility by including the base material layer containing 1-butene and alpha-olefin copolymer (A) and a propylene-type elastomer composition (B). .

  The expandable film of the present invention is used as a dicing film for use in various applications where expandability is required, for example, protective members such as optical elements and semiconductor devices, and is preferably used as a dicing film for semiconductors.

3. Manufacturing Method of Semiconductor Device The manufacturing method of the semiconductor device using the expandable film of the present invention may be any method. For example, 1) The dicing film of the present invention is provided on the semiconductor wafer and the low friction layer is provided. A step of attaching the surface opposite to the surface to be in contact with the semiconductor wafer; 2) a step of dicing the semiconductor wafer to obtain a semiconductor chip; and 3) a step of expanding the dicing film and picking up the semiconductor chip. Including. As the dicing film of the present invention, the expandable film of the present invention can be used.

  In the step 1), the surface of the semiconductor wafer in contact with the dicing film may be a circuit forming surface (front surface) or a non-circuit forming surface (back surface).

  The dicing in the step 2) may be blade dicing or laser dicing, and laser dicing is preferable because high-definition processing is possible. In laser dicing, laser light may be irradiated on the circuit forming surface (front surface) or non-circuit forming surface (back surface) of the semiconductor wafer. Since the dicing film of the present invention has high transparency, the laser beam is allowed to pass through the dicing film while being attached to the non-circuit forming surface (back surface) or the circuit forming surface (front surface) of the semiconductor wafer. And irradiating the semiconductor wafer.

  The means for expanding the dicing film in the step 3) is not particularly limited, and a method of extending the dicing film in contact with the stage by raising the stage of the expansion machine that supports the dicing film, or pulling in a direction parallel to the film surface. It can be a (expanding) method.

  2A to 2E are schematic views showing an example of a method for manufacturing a semiconductor device using a dicing film 20 having a low friction layer 21, a base material layer 23, an intermediate layer 25, and an adhesive layer 27 in this order. As shown in FIG. 2A, the non-circuit forming surface (back surface) of the wafer 31 is attached to the dicing film 20 (step 1). The dicing film 20 has a diameter larger than that of the wafer 31, and has a size that allows the peripheral edge portion to be fixed by the ring frame 33. Then, the peripheral edge of the dicing film 20 is fixed by the ring frame 33.

  Next, as shown in FIG. 2B, the laser light is irradiated onto the non-circuit forming surface (back surface) of the wafer 31 through the dicing film 20. Thereby, the wafer 31 is diced (cut) to obtain a semiconductor chip 31A (step 2).

  After completion of the dicing, as shown in FIG. 2C, the dicing film 20 with the semiconductor chip 31A is placed on the stage 35 of the expansion machine. Then, as shown in FIG. 2D, the stage 35 of the expander that supports the dicing film 20 is raised to expand (expand) the dicing film 20 (step 3).

  As a result, as shown in FIG. 2E, the interval between the semiconductor chips 31A obtained by dicing can be increased. Further, by expanding (expanding) the dicing film 20, shear stress is generated between the pressure-sensitive adhesive layer 27 of the dicing film 20 and the wafer 31, and the adhesive force between the wafer 31 and the pressure-sensitive adhesive layer 27 is reduced. The semiconductor chip 31A can be easily picked up. Thus, when the semiconductor chip 31A is picked up, the semiconductor chip 31A can be peeled off from the adhesive layer 27 of the dicing film 20.

  As described above, the dicing film of the present invention has high transparency. Therefore, as shown in FIG. 2B, the laser beam can be accurately irradiated onto the wafer 31 through the dicing film 20. Therefore, the manufacturing process of the semiconductor device can be simplified.

  In the following, the invention will be described in more detail with reference to examples. These examples do not limit the scope of the present invention.

1. Materials for Expandable Film (1) Raw Material for Low Friction Layer The low friction layer resin composition in the present invention was prepared as in Production Examples 1 and 2 below.
(Production Example 1)
1) Silicon-containing compound Hydrosilane A (HS (A), manufactured by Momentive Performance Materials Japan GK, product number: XF40-C2195) represented by the following formula was prepared.

2) Synthesis of single-end vinyl group-containing ethylene polymer (P-1) Preparation of polymerization catalyst (M1) Into a 100 ml reactor thoroughly dried and purged with nitrogen, 3.89 g of 3-cumyl-5-methylsalicylaldehyde ( 15 mmol), 30 ml of toluene, and 2.54 g (40% aqueous solution, 22.5 mmol) of ethylamine were added and stirred at room temperature for 5 hours. The reaction solution was compressed under reduced pressure and purified by silica gel column chromatography to obtain a yellow oily compound (L1).
¹ H-NMR (CDCl ₃ ): 1.69 (s, 6H), 2.34 (s, 3H), 3.33 (s, 3H), 6.93-7.29 (m, 7H), 8 .21 (s, 1H), 13.5 (s, 1H)

In a 100 ml reactor thoroughly dried and purged with argon, 1.12 g (4.0 mmol) of the obtained compound (L1) and 25 ml of diethyl ether were charged, cooled to −78 ° C. and stirred. To this, 2.58 ml of n-butyllithium (n-hexane solution, 1.55M, 4.00 mmol) was added dropwise over 5 minutes, and the mixture was stirred at the same temperature for 2 hours, then slowly warmed to room temperature, The lithium salt was prepared by further stirring at room temperature for 3 hours. This solution was added dropwise to 25 ml of a tetrahydrofuran solution containing 0.76 g (2.00 mmol) of ZrCl ₄ (THF) ₂ complex cooled to −78 ° C. After completion of the dropwise addition, stirring was continued while slowly raising the temperature to room temperature. Furthermore, after stirring at room temperature for 12 hours, the reaction solution was evaporated. The obtained solid was dissolved in 50 ml of methylene chloride, and unnecessary substances were removed with a glass filter. The filtrate was concentrated under reduced pressure, and the precipitated solid was reprecipitated with n-hexane and dried under reduced pressure to obtain 1.10 g (yield 79%) of a yellow powder compound (M1).
¹ H-NMR (CDCl ₃ ): 0.86-1.91 (m, 18H), 2.35 (s, 6H), 6.92-7.52 (m, 14H), 7.78 (s, 2H)

3) Synthesis of single-end vinyl group-containing ethylene polymer (N1) A stainless steel autoclave with an internal volume of 2000 ml that had been sufficiently purged with nitrogen was charged with 1000 ml of heptane at room temperature and heated to 150 ° C. Next, the inside of the autoclave was pressurized to 30 kg / cm ² G with ethylene to maintain the temperature. A hexane solution (1.00 mmol / ml in terms of aluminum atom) of MMAO (manufactured by Tosoh Finechem) was injected with 0.5 ml (0.5 mmol), and then a toluene solution (0.0002 mmol / ml) of compound (M1) 5 ml (0.0001 mmol) was injected to initiate the polymerization. After carrying out polymerization at 150 ° C. for 30 minutes in an ethylene gas atmosphere, the polymerization was stopped by press-fitting a small amount of methanol. The obtained polymer solution was added to 3 liters of methanol containing a small amount of hydrochloric acid to precipitate a polymer. The polymer was washed with methanol and dried under reduced pressure at 80 ° C. for 10 hours.

It was confirmed by ¹ H-NMR measurement that the obtained polymer was homopolyethylene (N1) having a double bond only at one end and had the following physical properties.
Melting point = 123 ° C.
Mw = 4770, Mw / Mn = 2.25 (GPC)
Terminal unsaturation rate = 97%

4) Synthesis of platinum catalyst composition (O1) In a 50 ml sample tube containing a magnetic stirrer chip, 0.50 g of platinum (II) chloride was suspended in 10 ml of the above hydrosilane A, and at room temperature under a nitrogen stream. Stir. After stirring for 190 hours, about 0.4 ml of the reaction solution was collected with a syringe, filtered using a 0.45 μm PTFE filter, and the filtrate was collected in a 10 ml sample tube. The platinum concentration was 3.8% by weight. A platinum catalyst composition (O1) was obtained.

5) Synthesis of Silylated Polyolefin (P1) 25.1 g (11.8 mmol) of the above synthesized one-end vinyl group-containing ethylene polymer (N1) was charged into a 300 ml two-necked flask, and under a nitrogen atmosphere, 8 0.7 g of the hydrosilane A (5.9 mmol; 11.8 mmol as Si—H group) and 150 μl (Pt) of a solution (O1-a) obtained by diluting the synthesized platinum catalyst composition (O1) 200 times with hydrosilane A In addition, 1.4 × 10 ⁻⁶ mmol) was further charged. The flask was set in a hot water bath that had been heated to an internal temperature of 130 ° C. in advance, and stirred. After about 3 minutes, the polymer melted. Then, after 6 hours, the mixture was cooled, about 200 ml of methanol was added, and the contents were taken out into a 300 ml beaker and stirred for 2 hours. Thereafter, the solid was collected by filtration, washed with methanol, and dried under reduced pressure at 60 ° C. and 2 hPa or less to obtain 33.1 g of a white solid silylated polyolefin (P1).

  As a result of NMR analysis of the obtained white solid silylated polyolefin (P1), the yield was 98%, the olefin conversion rate was 100%, and the isomerization rate was 2%. The silicone content in the silylated polyolefin (P1) was 30% by mass.

6) Preparation of resin composition for low friction layer To 95 parts by mass of linear low density polyethylene (Evolu SP2040, MFR = 3.8 g / 10 min), 5 parts by mass of the resulting silylated polyolefin (P1) was dry blended. Then, it was melt-mixed at a cylinder temperature of 200 ° C. with a TEM-26SS twin screw extruder (L / D = 60) manufactured by Toshiba Machine Co., to obtain a pellet-shaped resin composition 1. The silicone content in the obtained resin composition 1 was 30% by mass × 5/100 = 1.5% by mass.

(Production Example 2)
10 parts by mass of the resulting silylated polyolefin (P1) was dry blended with 90 parts by mass of linear low density polyethylene (Evolue SP2040), and a TEM-26SS twin screw extruder (L / D = 60) manufactured by Toshiba Machine Co., Ltd. ) And melt-mixed at a cylinder temperature of 200 ° C. to obtain a pellet-shaped resin composition 2. The silicone content in the obtained resin composition 2 was 30% by mass × 10/100 = 3% by mass.

  On the other hand, a comparative resin composition for a low friction layer was prepared as in Production Examples 3 and 4 below.

(Production Example 3)
After adding 2.5 parts by mass of silicone resin (product name BY27-002, polyethylene resin containing 50% by mass of silicone gum) to 97.5 parts by mass of Evolue SP2040, dry blending By mixing, the resin composition 3 was obtained. The silicone content in the obtained resin composition 3 was 50% by mass × 2.5 / 100 = 1.25% by mass.

(Production Example 4)
Evolue SP2040 was added to 95 parts by mass and 5 parts by mass of a silicone resin (manufactured by Toray Dow Corning Silicone Co., Ltd .: trade name BY27-002), and then mixed by dry blending to obtain a resin composition 4. The silicone content in the obtained resin composition 4 was 50% by mass × 5/100 = 2.5% by mass.

  The haze and MFR of the resin compositions obtained in Production Examples 1 to 4 were measured by the following methods.

(Haze)
The obtained resin composition was put into an extruder equipped with a full flight type screw,
A film having a thickness of 10 μm was obtained by extrusion from a single layer die. The haze of the obtained film was measured using a haze meter NDH5000.

(MFR)
The MFR of the obtained resin composition was measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kg according to ASTM D1238.

(2) Raw material for base material layer As 1-butene / α-olefin copolymer (A1), Tuffmer BL4000 manufactured by Mitsui Chemicals, Inc. was prepared.

The propylene elastomer composition (B1) was prepared as follows.
As the propylene / α-olefin copolymer (b1), propylene / ethylene / 1-butene = 70/10/20 (molar ratio) propylene / α by the method described in paragraph 0111 of International Publication No. 2012/042869. -Olefin copolymer was synthesized.
That is, after 8.3 ml of dry hexane, 100 g of 1-butene, and 1.0 mmol of triisobutylaluminum were charged at room temperature in a 2000 ml polymerization apparatus sufficiently purged with nitrogen, the temperature in the polymerization apparatus was raised to 40 ° C. The pressure in the system was increased to 0.76 MPa with propylene. Next, the pressure in the polymerization apparatus was adjusted to 0.8 MPa with ethylene. Next, 0.001 mmol of dimethylmethylene (3-tert-butyl-5-methylcyclopentadienyl) fluorenylzirconium dichloride was brought into contact with 0.3 mmol of methylaluminoxane (made by Tosoh Finechem) in terms of aluminum. The toluene solution was added to the polymerization apparatus, polymerized for 20 minutes while maintaining the internal pressure at 0.8 MPa with ethylene at an internal temperature of 40 ° C., and then 20 ml of methanol was added to stop the polymerization reaction. After depressurization, the polymer was precipitated from the polymerization solution in 2 L of methanol and dried at 130 ° C. for 12 hours under vacuum to obtain 36.4 g of a propylene / α-olefin copolymer (b1).

  Next, 95 parts by weight of the obtained propylene / α-olefin copolymer (b1) and 5 parts by weight of homopolypropylene (b2) were kneaded at 200 ° C. with a twin-screw extruder, and the propylene elastomer composition ( B1) was obtained.

  The 1-butene / α-olefin copolymer (A1) and the resulting propylene-based elastomer composition (B1) were mixed at a mass ratio of 50/50 to obtain a mixture.

  The density, tensile elastic modulus and MFR of the 1-butene / α-olefin copolymer (A1) and the mixture of the 1-butene / α-olefin copolymer (A1) and the propylene-based elastomer composition (B1) are as follows: It measured by the following method.

(density)
It measured using the density gradient tube method currently disclosed by Unexamined-Japanese-Patent No. 2001-33372. Specifically, a sample (solid) to be measured was melted by a melt indexer to obtain a strand. The strand was annealed, then cut to an appropriate size and put into a density gradient tube.

  As the density gradient tube, a glass cylindrical tube filled with a liquid having a continuous density gradient was used. Then, the density of the sample was read from the equilibrium position where the charged sample was stationary in the liquid. The liquid filled in the glass cylindrical tube was an ethanol-water mixed liquid defined in Table 2 of JIS K7112.

(Tensile modulus)
A film made of a sample to be measured was produced, and the tensile modulus was measured by a method based on ASTM D638. That is,
i) A film having a thickness of 100 μm was cut to prepare a strip-shaped sample piece having a width (TD direction) of 10 mm and a length (MD direction) of 100 mm.
ii) Next, in accordance with JIS K7161, the tensile modulus of the sample piece was measured with a tensile tester under conditions of a distance between chucks of 50 mm and a tensile speed of 300 mm / min. The tensile modulus was measured under conditions of a temperature of 23 ° C. and a relative humidity of 55%.

(MFR)
The MFR of the sample to be measured was measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kg in accordance with ASTM D1238.

(Yield point)
Moreover, in order to measure the said tensile elasticity modulus of the film which consists of a mixture (resin composition which comprises a base material layer) of 1-butene and alpha-olefin copolymer (A1) and a propylene-type elastomer composition (B1). In the tensile test, a stress-strain diagram was obtained, and it was confirmed that there was no yield point.

(3) Raw material for intermediate layer Tuffmer P0275 (registered trademark) manufactured by Mitsui Chemicals, Inc. was prepared.

(4) Raw material for pressure-sensitive adhesive layer A UV-curable pressure-sensitive adhesive layer composition was prepared by the following method. That is, 48 parts by weight of ethyl acrylate, 27 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of methyl acrylate, 5 parts by weight of glycidyl methacrylate, and 0.5 parts by weight of benzoyl peroxide as a polymerization initiator were mixed. This was dropped into a nitrogen-substituted flask containing 65 parts by weight of toluene and 50 parts by weight of ethyl acetate over 5 hours at 80 ° C. with stirring, and further stirred for 5 hours to be reacted. After completion of the reaction, the solution was cooled, 25 parts by weight of xylene, 2.5 parts by weight of acrylic acid, and 1.5 parts by weight of tetradecylbenzylammonium chloride were added thereto, and reacted at 80 ° C. for 10 hours while blowing air. An acrylic acid ester copolymer solution into which a photopolymerizable carbon-carbon double bond was introduced was obtained.

  In this solution, 7 parts by weight of benzoin as a photoinitiator and 100 parts by weight of a copolymer (solid content), 2 parts by weight of an isocyanate-based crosslinking agent (trade name: Olester P49-75S, manufactured by Mitsui Chemicals, Inc.) 1 part by weight of dipentaerythritol hexaacrylate (trade name: Aronix M-400, manufactured by Toagosei Co., Ltd.) is added as a low molecular weight compound having two or more photopolymerizable carbon-carbon double bonds in one molecule. And UV curable adhesive layer composition (U1) was obtained.

2. Production of expandable film (Example 1)
The resin composition 1 of Production Example 1, which is a raw material for the low friction layer, the raw material for the base material layer, and the raw material for the intermediate layer were respectively charged into each extruder equipped with a full flight type screw and melt-kneaded. . The extrusion temperature of the low friction layer, the base material layer, and the intermediate layer was 230 ° C., and three layers of molten resin were laminated in a multilayer die and coextruded. Thereby, a laminated film having a three-layer structure in which a low friction layer, a base material layer, and an intermediate layer were laminated in order was obtained.

  On the other hand, the prepared UV curable pressure-sensitive adhesive layer composition is a 38 μm thick PET film (release film, trade name SP-PET, manufactured by Tosero Co., Ltd.) whose surface is subjected to silicone treatment (mold release treatment). On the release-treated surface, a comma coater was applied and dried at 120 ° C. for 4 minutes to obtain a UV curable pressure-sensitive adhesive layer having a thickness of 5 μm.

  And the intermediate | middle layer of the produced said laminated film and the UV curable adhesive layer formed on PET film were bonded together and pressed with the dry laminator. Thereby, the UV curable pressure-sensitive adhesive layer was transferred onto the intermediate layer of the laminated film to obtain an expandable film. The thickness of each layer in the expandable film was a low-friction layer / base material layer / intermediate layer / adhesive layer = 10 μm / 60 μm / 50 μm / 5 μm having a four-layer structure as shown in FIG.

(Example 2, Comparative Examples 1-2)
An expandable film was obtained in the same manner as in Example 1 except that the resin composition of Production Example 1 as a raw material for the low friction layer was changed as shown in Table 1.

  The expandability, haze and adhesive strength of the obtained expandable film were measured by the following methods.

(Scalability)
On the pressure-sensitive adhesive layer of the obtained expandable film, an 8-inch ring frame was brought into close contact with a rubber roll, and the expandable film was fixed to the ring frame. Next, a 2 cm square lattice was filled with an oil pen on the surface of the low friction layer of the expandable film. At this time, the length in the MD direction and the length in the TD direction of the lattice were 12 cm, respectively. Next, as shown in FIG. 3A, the ring frame 43 was fixed to the expander so that the low friction layer of the expandable film 40 was in contact with the stage 41 of the expander. As the expansion machine, Hugle Electronics HS-1800 was used.

Then, as shown in FIG. 3B, when the expandable film 40 is expanded for each of the case where the stage 41 of the expander is raised by 15 mm (15 mm UP) and the case where the stage 41 is raised by 25 mm (25 mm UP), The length in the TD direction and the length in the MD direction were measured. The obtained measured value was applied to the following formula, and the expansion rate in each of the MD direction and the TD direction was obtained. And the average value of them was defined as “expansion rate”.
Expansion rate (MD direction, TD direction) (%) = 100 × length of lattice after expansion / length of lattice before expansion

  The expansion rate indicates the expansion rate of the expandable film on the stage 41. Since the stage lift is constant at 15 mm or 25 mm, the film on the stage with a low expansion rate does not expand greatly, and the film outside the stage (the film between the end of the stage and the ring frame) expands. Means that Therefore, the expansion rate corresponds to the expansion required in the dicing process of a semiconductor or the like that picks up the semiconductor chip corresponding to the lattice.

(Haze)
The haze of the obtained expandable film was measured using a haze meter NDH5000. A haze value of 9% or less was rated as ◯, and a haze value exceeding 9% as x.

(Adhesive force)
The adhesive strength of the adhesive layer of the obtained expandable film was measured in an environment of a temperature of 23 ° C. and a relative humidity of 50% according to the adhesive sheet test method described in JIS Z0237. Specifically, the obtained laminate was used as a test piece having a width of 25 mm. The release film was peeled off from the test piece, and the exposed adhesive layer was applied to a SUS-BA plate while applying pressure with a rubber roll of about 2 kg, and was placed in a constant environment at a temperature of 23 ° C. and a relative humidity of 50% for 60 minutes. placed. Subsequently, the adhesive force at the time of peeling this test piece from a SUS-BA board at a peeling speed of 300 mm / min in the 180 ° direction was measured. This adhesive strength was measured twice, and the average value was defined as “adhesive strength” (N / 25 mm).

Table 1 shows the evaluation results of Examples 1-2 and Comparative Examples 1-2.

  As shown in Table 1, the expandable films of Examples 1 and 2 have good expandability, have lower haze than the expandable films of Comparative Examples 1 and 2, and have high transparency. Recognize.

  The expandable films of Examples 1 and 2 have higher transparency than Comparative Examples 1 and 2 because the phase of LLDPE and silylated polyolefin (P1) in the low friction layer of the films of Examples 1 and 2 This is thought to be due to the high solubility.

  According to the present invention, a highly transparent expandable film can be provided. Such an expandable film is useful for laser dicing, for example.

10, 40 Expandable film 20 Dicing film 11, 21 Low friction layer 13, 23 Base layer 15, 25 Intermediate layer 17, 27 Adhesive layer 31 Semiconductor wafer 33, 43 Ring frame 35, 41 Stage

Claims (17)

An expandable film including a base material layer having a tensile modulus of 80 to 1000 MPa and a low friction layer,
The low friction layer,
100 parts by mass of one or more resins selected from the group consisting of thermoplastic resins and thermosetting resins;
A silylated polyolefin obtained by a reaction between a silicon-containing compound having a structural unit represented by the following formula (1) and a vinyl group-containing polyolefin having a number average molecular weight of 100 or more and 500,000 or less as measured by the GPC method (however, (Excluding silylated polyolefin obtained by reaction of a silicon-containing compound having two or more SiH groups in one molecule and a vinyl group-containing compound having two or more vinyl groups in one molecule) 0.01 to 10000 parts by mass A resin composition containing
An expandable film, wherein the expandable film has a haze of 9% or less.

(In the formula (1),
R ¹ is a hydrogen atom, a halogen atom or a hydrocarbon group;
Y ¹ is O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group)   The expandable film according to claim 1, wherein the resin contained in the resin composition is a polyolefin.   The expandable film according to claim 1 or 2, wherein the base material layer does not have a yield point, or the elongation at the yield point is 16% or more. The expandable film according to any one of claims 1 to 3, wherein the silicon-containing compound has a structure represented by the following formula (2).

(In the formula (2),
R ²¹ and R ²³ are each independently a hydrogen atom, a halogen atom or a hydrocarbon group;
Y ²¹ and Y ²² are each independently O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group);
m and n are each independently 0 or 1;
R ²¹ , R ²³ , Y ²¹ and Y ²² may be the same or different from each other;
R ²² and R ²⁴ are each independently a halogen atom or a hydrocarbon group;
Z is a divalent group represented by the following formula (3);

(In formula (3),
R ²⁵ and R ²⁶ are each independently a hydrogen atom, a halogen atom or a hydrocarbon group;
Y ²³ is each independently O, S or NR ³⁰ (R ³⁰ is a hydrogen atom or a hydrocarbon group);
l is an integer from 0 to 10,000;
In the formula (2), when m = n = 0, at least one of the plurality of R ²⁵ and R ²⁶ in the formula (3) is a hydrogen atom)) The expandable film according to claim 4, wherein R ²¹ and R ^{23 in} the formula (2) and R ²⁵ and R ^{26 in} the formula (3) are all hydrocarbon groups.   The expandable film according to any one of claims 1 to 5, wherein the silicon-containing compound contains 3 or more silicon atoms. The expandable film according to any one of claims 1 to 6, wherein the vinyl group-containing polyolefin has a structure represented by the following formula (4).

(In Formula (4), A is a polymer chain of a monomer containing an α-olefin having 2 to 50 carbon atoms)   The expandable film according to claim 7, wherein A in the formula (4) is a homopolymer chain of ethylene.   The expandable film according to any one of claims 1 to 8, wherein the resin contained in the resin composition is polyethylene. The base material layer is
A 1-butene / α-olefin copolymer (A) having a tensile elastic modulus at 23 ° C. of 100 to 500 MPa,
A propylene-based elastomer composition (B) containing a propylene / α-olefin copolymer (b1) and having a tensile elastic modulus at 23 ° C. of 8 to 500 MPa,
The expandable film according to any one of claims 1 to 9, wherein the content of (B) is 30 to 70 parts by weight with respect to 100 parts by weight of the total of (A) and (B).   The expandable film according to claim 10, wherein the propylene-based elastomer composition (B) has a tensile elastic modulus at 23 ° C of 10 to 50 MPa.   The expansion according to claim 10 or 11, wherein the propylene-based elastomer composition (B) further comprises 1 to 70 parts by weight of polypropylene (b2) with respect to 100 parts by weight of the propylene-based elastomer composition (B). Sex film. The substrate layer is a surface opposite to the surface on which the low friction layer is disposed, and further has a pressure-sensitive adhesive layer provided on the outermost surface of the expandable film;
Measured according to JIS Z0237 when the pressure-sensitive adhesive layer is adhered to the surface of a SUS-304-BA plate and left for 60 minutes and then peeled off from the surface of the SUS-304-BA plate. The expandable film as described in any one of Claims 1-12 whose adhesive force is 0.1-10 N / 25mm. Further comprising an intermediate layer between the base material layer and the pressure-sensitive adhesive layer,
In the intermediate layer, the tensile elastic modulus E (25) at 25 ° C. and the tensile elastic modulus E (60) at 60 ° C. satisfy the relationship of E (60) / E (25) <0.1, and the 25 ° C. The expandable film according to claim 13, wherein the tensile elastic modulus E (25) at 1 to 10 MPa. The expandable film according to claim 14, wherein the intermediate layer comprises an olefin copolymer having a density of 800 to 890 kg / m ³ . A step of attaching the expandable film according to any one of claims 1 to 15 to a semiconductor wafer via a surface opposite to the surface on which the low friction layer of the expandable film is provided,
Obtaining a semiconductor chip by dicing the semiconductor wafer;
Expanding the expandable film and picking up the semiconductor chip. A method for manufacturing a semiconductor device. The method of manufacturing a semiconductor device according to claim 16, wherein the dicing is performed by irradiating the semiconductor wafer with laser light through the expandable film.

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