JP2015214658A - Expandable substrate film, expandable adhesive film, dicing film, production method of expandable substrate film and production method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expandable substrate film which is suppressed in necking and has high and uniform expandability.SOLUTION: An expandable substrate film contains a composition (X) comprising a polymer (A) which contains 90-100 mol% of structural units (P) derived from 4-methyl-1-pentene and has a ratio of structural units derived from α-olefins other than 4-methyl-1-pentene to all the structural units of 0-10 mol% and a copolymer (B) which contains 65 mol% or more and less than 90 mol% of the structural units (P) and 10-35 mol% of structural units derived from 2-20C α-olefins other than 4-methyl-1-pentene, and the content of (A) to the total of (A) and (B) of 100 pts.mass is 50-99 pts.mass.

Description

  The present invention relates to an expandable base film, an expandable adhesive film, a dicing film, a method for manufacturing an expandable base film, and a method for manufacturing a semiconductor device.

  As a manufacturing method of a semiconductor device, a dicing film provided with a base film and an adhesive layer is attached to a semiconductor substrate (for example, a silicon wafer), and then the semiconductor substrate is dicing blade (dicing saw), laser light, plasma, etc. A method of obtaining a plurality of semiconductor chips (chip-shaped semiconductor devices) separated from each other by dicing the substrate and then expanding the dicing film and then picking up at least one of the plurality of semiconductor chips is known. (For example, see Patent Documents 1 to 7).

  In addition, after attaching a dicing film to the semiconductor substrate, before dicing, wiring of a circuit formed on the semiconductor substrate, electrode formation (bonding), resin sealing (baking) is performed, and then WLP (dicing performed) A manufacturing method called “wafer level package” is known (see, for example, Patent Document 8).

  Examples of the material for the base film of the dicing film include polyvinyl chloride (for example, see Patent Document 9), a mixture of an ethylene / vinyl acetate copolymer and a polyolefin resin (for example, see Patent Document 10), and the like. Are known.

JP-A-2-215528 JP 2012-188597 A JP 2008-4836 A JP 2009-267389 A JP 2002-343747 A Japanese Patent No. 4945014 JP 2012-188597 A JP 2008-16539 A Japanese Patent Laid-Open No. 2002-235055 JP 2004-303999 A

As described above, in the method of manufacturing a semiconductor device using a dicing film, the dicing film is expanded after dicing the semiconductor substrate.
The reason for expanding the dicing film is to reduce the adhesive force between the semiconductor chip and the dicing film due to the shear stress between the semiconductor chip and the dicing film that occurs during the expansion, thereby making it easier to pick up the semiconductor chip from the dicing film. It is to do. Another reason for expanding the dicing film is to make it easier to pick up semiconductor chips from the dicing film by increasing the interval between the plurality of semiconductor chips.

Thus, the dicing film is a film that is expanded after the processing (dicing) of the semiconductor substrate.
In order to improve workability when picking up semiconductor chips, dicing films are necked during expansion (the film stretches non-uniformly to create holes in the film, or the film thickness becomes non-uniform). It is desirable that the whole be stretched uniformly to some extent.

This invention is made | formed in view of the said situation, and it aims at providing the expandable base film which has high uniform expansion property which is hard to neck, and its manufacturing method.
Moreover, an object of this invention is to provide the expandable adhesive film and dicing film provided with the said expandable base film.
In addition, the present invention can provide a method for manufacturing a semiconductor device that is excellent in workability when picking up a semiconductor chip obtained from a semiconductor substrate.

Specific means for solving the above-described problems are as follows.
<1> The proportion of structural units derived from α-olefin other than 4-methyl-1-pentene having 90 to 100 mol% of structural units derived from 4-methyl-1-pentene The number of carbon atoms other than the polymer (A) which is 0 mol% or more and 10 mol% or less and the structural unit derived from 4-methyl-1-pentene is 65 mol% or more and less than 90 mol% and 4-methyl-1-pentene A copolymer (B) having 10 to 35 mol% of structural units derived from 2 or more and 20 or less α-olefin, and the content of the polymer (A) is the polymer (A) ) And the copolymer (B), the expandable substrate film contains the composition (X) that is 50 parts by mass or more and 99 parts by mass or less with respect to 100 parts by mass in total.
<2> The expandable base film according to <1>, wherein the polymer (A) has a tensile elastic modulus at 23 ° C. measured in accordance with JIS K7127 (1999) of 500 MPa to 2000 MPa.
<3> The expandable substrate according to <1> or <2>, wherein the copolymer (B) contains 70 mol% or more and less than 90 mol% of a structural unit derived from the 4-methyl-1-pentene. the film.
<4> Any one of <1> to <3>, wherein the structural unit derived from the α-olefin having 2 to 20 carbon atoms of the copolymer (B) is a structural unit derived from propylene. The expandable base film according to Item.

<5> A thermoplastic elastomer (Y) is further contained, and the content of the thermoplastic elastomer (Y) is 3 with respect to a total of 100 parts by mass of the composition (X) and the thermoplastic elastomer (Y). The melting point TmY2 derived from the thermoplastic elastomer (Y) measured by a differential scanning calorimeter (DSC) with respect to the expandable base film is 200 ° C. or less or substantially equal to the melting point TmY2. The expandable substrate film according to any one of <1> to <4>, which is not observed in <1>.
<6> A thermoplastic elastomer (Y) is further contained, and the content of the thermoplastic elastomer (Y) is 3 with respect to 100 parts by mass in total of the composition (X) and the thermoplastic elastomer (Y). The melting point TmY1 measured by a differential scanning calorimeter (DSC) of the thermoplastic elastomer (Y) is 200 ° C. or less, or the melting point TmY1 is not substantially observed. <1> to The expandable base film <7> according to any one of <4>, wherein the thermoplastic elastomer (Y) has a tensile elastic modulus at 23 ° C. measured in accordance with JIS K7127 (1999) of 1 MPa to 1500 MPa. The expandable substrate film according to <5> or <6>.
<8> The expandable base film according to any one of <5> to <7>, wherein the thermoplastic elastomer (Y) is composed of an olefin elastomer and / or a styrene elastomer.
<9> The expandable base film according to any one of <5> to <8>, wherein the density of the thermoplastic elastomer (Y) is 850 kg / m ³ or more and 900 kg / m ³ or less.

<10> An expandable pressure-sensitive adhesive film comprising a base material layer comprising the expandable base material film according to any one of <1> to <9>, and a pressure-sensitive adhesive layer.
<11> The expandable pressure-sensitive adhesive film according to <10>, having the pressure-sensitive adhesive layer on the outermost surface.

<12> A dicing film comprising the expandable adhesive film according to <10> or <11>.

<13> The proportion of structural units derived from α-olefin other than 4-methyl-1-pentene having 90 to 100 mol% of structural units derived from 4-methyl-1-pentene The number of carbon atoms other than the polymer (A) which is 0 mol% or more and 10 mol% or less and the structural unit derived from 4-methyl-1-pentene is 65 mol% or more and less than 90 mol% and 4-methyl-1-pentene A copolymer (B) having 10 to 35 mol% of structural units derived from 2 or more and 20 or less α-olefin, and the content of the polymer (A) is the polymer (A) ) And the copolymer (B), including a step of forming a melt-kneaded product containing the composition (X) that is 50 parts by mass or more and 99 parts by mass or less with respect to 100 parts by mass in total <1> to <4> Extensibility as described in any one of Method of manufacturing a wood film.
<14> The proportion of structural units derived from α-olefin other than 4-methyl-1-pentene having 90 to 100 mol% of structural units derived from 4-methyl-1-pentene 65 mol% or more and less than 90 mol% of the structural unit derived from the polymer (A) and 4-methyl-1-pentene which is 0 mol% or more and 10 mol% or less and 2 carbon atoms other than 4-methyl-1-pentene A copolymer (B) having 10 to 35 mol% of structural units derived from 20 or less α-olefin, wherein the content of the polymer (A) is the same as that of the polymer (A) and The melting point TmY1 obtained by a composition (X) that is 50 parts by mass or more and 99 parts by mass or less and a differential scanning calorimeter (DSC) with respect to 100 parts by mass in total with the copolymer (B) is 200 ° C. or less. The melting point TmY1 is Thermoplastic elastomer (Y) not qualitatively observed, and the content of the thermoplastic elastomer (Y) is 100 parts by mass in total of the composition (X) and the thermoplastic elastomer (Y) The manufacturing method of the expandable base film as described in any one of <5>-<9> including the process of shape | molding the melt-kneaded material which is 3 mass parts or more and 50 mass parts or less.

<15> The semiconductor substrate is attached to the dicing film according to <12> so that the adhesive layer of the dicing film and the semiconductor substrate are in contact with each other, and the dicing film is attached. A dicing step of dicing the semiconductor substrate, an expansion step of expanding the dicing film after the dicing step to obtain a plurality of semiconductor chips separated from each other, and picking up at least one of the plurality of semiconductor chips A method for manufacturing a semiconductor device, comprising: a pickup step.
<16> The dicing film according to <12> is disposed on a surface opposite to the circuit surface of the semiconductor substrate having a circuit surface only on one surface, and the pressure-sensitive adhesive layer of the dicing film is opposite to the circuit surface. An adhering step for adhering the surface of the semiconductor substrate, a sealing step for sealing the circuit surface of the semiconductor substrate, a dicing step for dicing the semiconductor substrate on which the dicing film is adhered, A method for manufacturing a semiconductor device, comprising: an expansion step of expanding the dicing film after the dicing step to obtain a plurality of semiconductor chips separated from each other; and a pickup step of picking up at least one of the plurality of semiconductor chips. .

In this specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Moreover, in this specification, when mentioning about content of each component in a composition, when there exist two or more substances applicable to each component in a composition, it exists in a composition unless there is particular notice. It means the total amount of multiple substances.

ADVANTAGE OF THE INVENTION According to this invention, the expandable base film which has the high uniform expansion property which is hard to neck, and its manufacturing method can be provided.
Moreover, according to this invention, the expandable adhesive film and dicing film provided with the said expandable base film can be provided.
In addition, according to the present invention, it is possible to provide a method of manufacturing a semiconductor device that is excellent in workability when picking up a semiconductor chip obtained from a semiconductor substrate.

It is the top view and side view explaining the expansion test method of the expandable base film in a present Example. It is a side view explaining the expansion test method of the expandable base film in a present Example.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. be able to.

[Extensible base film]
The expandable substrate film of the present invention has 90 to 100 mol% of a structural unit derived from 4-methyl-1-pentene (hereinafter sometimes referred to as “structural unit (P)”). A polymer in which the proportion of structural units derived from an α-olefin other than methyl-1-pentene (hereinafter sometimes referred to as “structural units (AQ)”) is from 0 mol% to 10 mol% ( The structural unit (P) derived from A) and 4-methyl-1-pentene is derived from an α-olefin having 65 to 90 mol% and 2 to 20 carbon atoms other than 4-methyl-1-pentene. A copolymer (B) having 10 to 35 mol% of a structural unit (hereinafter sometimes referred to as “structural unit (BQ)”), wherein the content of the polymer (A) is Copolymer (A) and copolymer (B) The composition (X) which is 50 mass parts or more and 99 mass parts or less is contained with respect to 100 mass parts in total.

ADVANTAGE OF THE INVENTION According to this invention, the expandable base film which has the high uniform expansion property which is hard to neck is obtained.
The reason why such an effect is obtained is presumed as follows.

As described above, the expandable substrate film of the present invention has a polymer (A) having 90 mol% or more of the structural unit (P) and a range of 65 mol% or more and less than 90 mol% of the structural unit (P). The composition (X) is used in combination with the copolymer (B) contained in
By adopting a structure in which the copolymer (B) is appropriately dispersed with respect to the polymer (A) as in the present invention, the flexible component is appropriately compatible up to the crystal part of the polymer (A). Since it is dispersed, uniform expandability can be obtained without necking. This also makes it difficult to exhibit anisotropy of tear strength and the like.
Therefore, in this invention, compared with the case where only any one of a polymer (A) and a copolymer (B) is used as a composition (X), it is excellent in the heat resistance and elongation balance of a film. For example, when only the polymer (A) is used, it becomes easy to neck due to the rigidity of the film. On the other hand, when only the copolymer (B) is used, a flexible film is obtained as compared with the polymer (A), so that it is difficult to neck, but the mechanical properties when used as an expandable film are inferior.

  For the above reasons, according to the present invention, it is considered that an expandable base film having high and uniform expandability that is difficult to necking can be obtained.

Moreover, the expandable base film of the present invention further contains a thermoplastic elastomer (Y), and 3 parts by mass or more and 50 parts by mass with respect to 100 parts by mass in total of the composition (X) and the thermoplastic elastomer (Y). The melting point TmY2 derived from the thermoplastic elastomer (Y) measured by a differential scanning calorimeter (DSC) with respect to the expandable substrate film is 200 parts C or less or the melting point TmY2 is substantially observed. It is desirable that the melting point TmY1 measured by a differential scanning calorimeter (DSC) of the thermoplastic elastomer (Y) is not higher than 200 ° C. or the melting point TmY1 is not substantially observed.
When the expandable substrate film further contains the thermoplastic elastomer (Y) that satisfies the above conditions, there is an advantage that the film is given flexibility and uniform expandability is enhanced.

  The expandable substrate film of the present invention is suitable as a substrate film for a semiconductor film (particularly a semiconductor dicing film). However, the use of the expandable base film of the present invention is not limited to the base film of a film for semiconductors, and is also suitable for base films of various films that are difficult to neck and require high and uniform expandability. is there.

  Hereinafter, each component contained in the expandable base film of the present invention will be described.

[Composition (X)]
Composition (X) is a composition containing a polymer (A) and a copolymer (B). That is, as described above, the composition (X) comprises the polymer (A) having 90 to 100 mol% of the structural unit (P) derived from 4-methyl-1-pentene and the structural unit (P). And a copolymer (B) having a content of 65 mol% or more and less than 90 mol%.
Hereinafter, each of a polymer (A) and a copolymer (B) is demonstrated.

<Polymer (A)>
The polymer (A) has 90 to 100 mol% of a structural unit (P) derived from 4-methyl-1-pentene, and is derived from an α-olefin other than 4-methyl-1-pentene. The ratio of units (AQ) to all structural units is 0 mol% or more and 10 mol% or less. That is, the polymer (A) may be a homopolymer of 4-methyl-1-pentene, or a copolymer of 4-methyl-1-pentene and an α-olefin other than 4-methyl-1-pentene. In the case of the copolymer, 90% by mole or more of the structural unit (P) is included.

  Examples of the α-olefin other than 4-methyl-1-pentene forming the structural unit (AQ) include α-olefins having 2 to 20 carbon atoms. Examples of the α-olefin having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-hexadecene, Examples include heptadecene, 1-octadecene, and 1-eicocene. The α-olefin forming the structural unit (AQ) is preferably an olefin having 8 to 18 carbon atoms from the viewpoint of imparting an appropriate elastic modulus, flexibility, and flexibility to the film.

The content rate of the structural unit (X) in a polymer (A) is 90 to 100 mol%, and 95 to 100 mol% is preferable.
When the content of the structural unit (X) in the polymer (A) is 90 mol% or more, the heat resistance of the expandable substrate film can be obtained, and the elastic modulus of the film suitable for handling can be obtained. There is an advantage.

In the polymer (A), other than structural units derived from 4-methyl-1-pentene and structural units derived from α-olefins other than 4-methyl-1-pentene, as long as the effects of the present invention are not impaired. The structural unit may be included.
In addition, about the measuring method of the said other structural unit and the content rate (mol%) of each structural unit, the measuring method by < ¹³ > C-NMR can be used similarly to the copolymer (B) mentioned later.

  The tensile elastic modulus at 23 ° C. measured according to JIS K7127 (1999) of the polymer (A) is preferably 500 MPa or more and 2000 MPa or less, and more preferably 800 MPa or more and 1500 MPa or less. When the tensile elastic modulus is in the above range, the film can be easily expanded as compared with the case where the tensile elastic modulus is larger than the above range, and the handling property is better than that when the tensile elastic modulus is smaller than the above range.

The weight average molecular weight of the polymer (A) (Mw) is the terms of the film formability, it is 1 × ¹⁰ 4 ~2 × ^{10 6} preferably is the 1 × ¹⁰ 4 ~1 × ^{10 6} Is more preferable.

  The weight average molecular weight (Mw) of the polymer (A), and the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) are the following gel permeation chromatography. It is a value calculated by a standard polystyrene conversion method using (GPC).

~conditions~
Measuring device: GPC (ALC / GPC 150-C plus type, suggested refractometer detector integrated type, manufactured by Waters)
Column: 2 GMH6-HT (manufactured by Tosoh Corp.) and 2 GMH6-HTL (manufactured by Tosoh Corp.) connected in series Eluent: o-dichlorobenzene Column temperature: 140 ° C
Flow rate: 1.0 mL / min

The melting point (Tm) of the polymer (A) is preferably 200 ° C to 245 ° C, and more preferably 200 ° C to 240 ° C. When the melting point (Tm) of the polymer (A) is in the above range, the film has an appropriate elastic modulus as compared with the case where the melting point (Tm) is higher than the above range, and the heat resistance is better than that when the melting point (Tm) is lower than the above range. .
The melting point (Tm) of the polymer (A) is a value measured by the following method using a differential scanning calorimeter (DSC).
About 5 mg of the polymer (A) is sealed in a measurement aluminum pan of a differential scanning calorimeter (DSC220C type) manufactured by Seiko Instruments Inc. and heated from room temperature to 200 ° C. at 10 ° C./min. In order to completely melt the polymer (A), the polymer is held at 200 ° C. for 5 minutes and then cooled to −50 ° C. at 10 ° C./min. After 5 minutes at −50 ° C., the second heating is performed to 200 ° C. at 10 ° C./min, and the peak temperature (° C.) at the second heating is defined as the melting point (Tm) of the polymer. When a plurality of peaks are detected, the peak detected on the highest temperature side is adopted.

Density is measured according to JIS of the polymer (A) K7112 (Density gradient column method) is preferably from 825~840 (kg / ^{m 3),} is 830~835 (kg / ^{m 3)} Is more preferable. When the density is within the above range, the mechanical strength of the film is higher than when the density is smaller than the above range, and the film tends to expand more easily than when the density is larger than the above range.

  The melt flow rate (MFR) of the polymer (A) measured at 260 ° C. and a load of 5 kg in accordance with ASTM D1238 is easily mixed with the thermoplastic elastomer (Y) described later in the extruder and can be coextruded. However, it is usually 0.5 g / 10 min to 150 g / 10 min, more preferably 1 g / 10 min to 50 g / 10 min. If MFR is in the above range, it is easy to extrude to a relatively uniform film thickness.

The polymer (A) preferably has an intrinsic viscosity [η] measured at 135 ° C. in a decalin solvent of 0.5 dl / g to 5.0 dl / g, preferably 0.5 dl / g to 4.0 dl. / G is more preferable. When the intrinsic viscosity [η] of the polymer (A) is within the above range, the low-molecular-weight material is small and the stickiness of the film is reduced, and extrusion film formation becomes possible.
The intrinsic viscosity [η] of the polymer (A) is a value measured by the following method using an Ubbelohde viscometer.
After dissolving 20 mg of the polymer (A) in 25 ml of decalin, the specific viscosity ηsp is measured in an oil bath at 135 ° C. using an Ubbelohde viscometer. After 5 ml of decalin is added to the decalin solution for dilution, the specific viscosity ηsp is measured in the same manner as described above. This dilution operation is further repeated twice, and the value of ηsp / C when the concentration (C) is extrapolated to 0 is obtained as the intrinsic viscosity [η] (unit: dl / g) (see the following formula).
[Η] = lim (ηsp / C) (C → 0) Expression

  The polymer (A) is preferably a highly crystalline polymer from the viewpoint of obtaining a film that is not easily torn. The crystalline polymer may be either a polymer having an isotactic structure or a polymer having a syndiotactic structure, and is particularly preferably a polymer having an isotactic structure. It is easy to obtain. Furthermore, the polymer (A) is not particularly limited as long as the polymer (A) can be formed into a film and has a strength that can be used as an expandable substrate film.

  The polymer (A) may be directly produced by polymerizing olefins, or may be produced by thermally decomposing a high molecular weight 4-methyl-1-pentene polymer. Further, the polymer (A) may be purified by a method such as solvent fractionation, which is fractionated based on a difference in solubility in a solvent, or molecular distillation, which is fractionated based on a difference in boiling point.

  When the polymer (A) is directly produced by a polymerization reaction, for example, 4-methyl-1-pentene and an α-olefin to be copolymerized if necessary, the type of polymerization catalyst, the polymerization temperature, hydrogenation during polymerization The melting point, stereoregularity, molecular weight and the like are controlled by adjusting the amount and the like. The method for producing the polymer (A) by a polymerization reaction may be a known method. For example, it can be produced by a method using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst, preferably using a metallocene catalyst. On the other hand, when the polymer (A) is produced by thermal decomposition of a higher molecular weight 4-methyl-1-pentene polymer, it is controlled to the desired molecular weight by controlling the temperature and time of the thermal decomposition. To do.

  In addition to the polymer (A) produced as described above, a commercially available polymer such as TPX manufactured by Mitsui Chemicals, Inc. may be used.

<Copolymer (B)>
The copolymer (B) has a structural unit (P) derived from 4-methyl-1-pentene of 65 mol% or more and less than 90 mol%, and having 2 to 20 carbon atoms other than 4-methyl-1-pentene. The structural unit (BQ) derived from an α-olefin is 10 mol% or more and 35 mol% or less.

The content of the structural unit (P) in the copolymer (B) is 65 mol% or more and less than 90 mol%, preferably 68 mol% or more and less than 90 mol%, more preferably 68 mol% or more and less than 86 mol%. 70 mol% or more and less than 86 mol% is particularly preferable.
The stress relaxation property of a film improves because the content rate of the structural unit (P) in a copolymer (B) is 65 mol% or more.
When the content of the structural unit (P) in the copolymer (B) is less than 90 mol%, the anisotropy of tensile elongation at break and the anisotropy of tear strength are reduced.

The content of the structural unit (BQ) in the copolymer (B) (when the structural unit (BQ) is 2 or more, the total content of the 2 or more) is 10 mol% or more and 35 mol% or less. Yes, it is preferably 10 mol% or more and 30 mol% or less, more preferably 10 mol% or more and 25 mol% or less, and particularly preferably 10 mol% or more and 20 mol% or less.
When the content of the structural unit (BQ) in the copolymer (B) is 10 mol% or more, the anisotropy of tensile elongation at break and the anisotropy of tear strength are reduced.
The stress relaxation property of a film improves because the content rate of the structural unit (BQ) in a copolymer (B) is 35 mol% or less.

The α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene that forms the structural unit (BQ) further reduces the anisotropy of tensile elongation at break and the anisotropy of tear strength. From the viewpoint, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-hexadecene and 1-octadecene are preferable, and propylene, 1-octene, 1-decene, 1-hexadecene and 1-octadecene are preferable. Are more preferable, ethylene, propylene, and butene are still more preferable, and propylene is particularly preferable.
Moreover, the impact resistance of an expandable base film also improves that the said alpha olefin is the said preferable range.
In addition, only 1 type may be used for the alpha olefin which forms a structural unit (BQ), and it may combine 2 or more types.
The structural unit (BQ) may be the same as or different from the structural unit (AQ) when the polymer (A) includes the structural unit (AQ).

The copolymer (B) is a structural unit derived from 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene, as long as the effects of the present invention are not impaired. Other structural units other than the structural unit derived from may be included.
Examples of the monomer that forms other structural units include cyclic olefins, aromatic vinyl compounds, conjugated dienes, non-conjugated polyenes, functional vinyl compounds, hydroxyl group-containing olefins, halogenated olefins, and the like.
As the cyclic olefin, aromatic vinyl compound, conjugated diene, non-conjugated polyene, functional vinyl compound, hydroxyl group-containing olefin, and halogenated olefin, for example, the compounds described in paragraphs 0034 to 0041 of JP2013-169585A are used. be able to.

As the monomer forming the other structural unit, vinylcyclohexane and styrene are particularly preferable.
When the copolymer (B) contains the above other structural units, the above other structural units may be contained in only one kind, or may be contained in two or more kinds.

The content (mol%) of each structural unit in the copolymer (B) can be measured by the following method (measurement method by ¹³ C-NMR).

~conditions~
Measuring apparatus: Nuclear magnetic resonance apparatus (ECP500 type, manufactured by JEOL Ltd.)
Observation nucleus: ¹³ C (125 MHz)
Sequence: Single pulse proton decoupling Pulse width: 4.7 μsec (45 ° pulse)
Repeat time: 5.5 seconds Accumulated number: 10,000 times or more Solvent: Orthodichlorobenzene / deuterated benzene (volume ratio: 80/20) mixed solvent Sample concentration: 55 mg / 0.6 mL
Measurement temperature: 120 ° C
Standard value of chemical shift: 27.50ppm

  The tensile elastic modulus at 23 ° C. measured according to JIS K7127 (1999) of the copolymer (B) is preferably 50 MPa to 2000 MPa, and more preferably 100 MPa to 1700 MPa. When the tensile elastic modulus is in the above range, the film can be easily expanded as compared with the case where the tensile elastic modulus is larger than the above range, and the handling property is better than that when the tensile elastic modulus is smaller than the above range.

The weight average molecular weight of the copolymer (B) (Mw), from the viewpoint of film formability, it is 1 × ¹⁰ 4 ~2 × ^{10 6} preferably is the 1 × ¹⁰ 4 ~1 × ^{10 6} It is more preferable.
The molecular weight distribution (Mw / Mn) of the copolymer (B) is preferably 1.0 to 3.5, and preferably 1.1 to 3.0, from the viewpoints of film stickiness and appearance. More preferred.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the copolymer (B) are the same methods as the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer (A). Is a value calculated by.

The melting point (Tm) of the copolymer (B) is not observed or is preferably 100 ° C to 200 ° C, more preferably not observed, or more preferably 110 ° C to 180 ° C.
The melting point (Tm) of the copolymer (B) is a value measured by the same method as the melting point (Tm) of the polymer (A).

The density of copolymer (B), from the viewpoint of handling ^properties, is preferably ^{820kg / m 3 ~870kg / m 3} , more preferably ^{830kg / m 3 ~850kg / m 3} .
The density of the copolymer (B) is a value measured according to JIS K7112 (density gradient tube method).

The melt flow rate (MFR) of the copolymer (B) is preferably 0.1 g / 10 min to 100 g / 10 min, and preferably 0.5 g / 10 min to 50 g from the viewpoint of fluidity during molding. / 10 min is more preferable, and 0.5 g / 10 min to 30 g / 10 min is still more preferable.
The melt flow rate (MFR) of the copolymer (B) is a value measured at 230 ° C. and a load of 2.16 kg in accordance with ASTM D1238.

The copolymer (B) forms a film having a thickness of 50 μm, and the maximum value of the loss tangent (tan δ) measured 3 days after the film formation is within a temperature range of −50 ° C. to 50 ° C., preferably It is preferably in the temperature range of 0 ° C. to 45 ° C., more preferably 0 ° C. to 40 ° C., and the maximum value of the loss tangent (tan δ) is preferably 0.2 or more, and more preferably 0.4 or more. More preferably, it is 0.8 or more, more preferably 1.0 or more. The copolymer (B) is more excellent in stress relaxation properties when the maximum value of the loss tangent (tan δ) is within the above temperature range and the maximum value is 0.2 or more.
The temperature at which the maximum value of the loss tangent (tan δ) of the copolymer (B) and the maximum value thereof are indicated are the temperature at which the maximum value of the loss tangent (tan δ) of the polymer (A) and the maximum value thereof are indicated. It is a value obtained by the same measurement.

The copolymer (B) preferably has an intrinsic viscosity [η] measured at 135 ° C. in a decalin solvent of 0.5 dl / g to 5.0 dl / g, preferably 0.5 dl / g to 4. More preferably, it is 0 dl / g. When the intrinsic viscosity [η] of the copolymer (B) is within the above range, the low molecular weight material is small and the stickiness of the film is reduced, and extrusion film formation becomes possible.
The intrinsic viscosity [η] of the copolymer (B) is a value measured by the same method as the intrinsic viscosity [η] of the polymer (A).

  The copolymer (B) can be synthesized by a conventionally known metallocene catalyst system by, for example, a method described in International Publication No. 2005/121192, International Publication No. 2011/055803, or the like.

<Composition (X)>
The mixing ratio of the polymer (A) and the copolymer (B) in the composition (X) is the content of the polymer (A) with respect to 100 parts by mass in total of the polymer (A) and the copolymer (B). The amount is preferably from 50 parts by weight to 99 parts by weight, more preferably from 60 parts by weight to 99 parts by weight, and particularly preferably from 70 parts by weight to 98 parts by weight.
When the content of the polymer (A) is in the above range, a film having excellent heat resistance as compared with the case where the content is less than the above range and excellent in stretchability as compared with the case where the content is higher than the above range can be obtained.

  The combination of the weight average molecular weight of the polymer (A) contained in the composition (X) and the weight average molecular weight of the copolymer (B) is such that the weight average molecular weight of the polymer (A) is that of the copolymer (B). The weight average molecular weight is preferably 0.5 to 3 times, more preferably 0.6 to 2.5 times.

  The tensile elastic modulus at 23 ° C. measured according to JIS K7127 (1999) of the composition (X) is preferably 500 MPa to 2000 MPa, more preferably 600 MPa to 1800 MPa, and particularly preferably 600 MPa to 1400 MPa. When the tensile elastic modulus is in the above range, the film can be easily expanded as compared with the case where the tensile elastic modulus is larger than the above range, and the handling property is better than that when the tensile elastic modulus is smaller than the above range.

The composition (X) can be obtained by mixing the polymer (A) and the copolymer (B) in the above proportions. For example, the composition (X) may be obtained directly by a polymerization reaction of olefins. .
When the composition (X) is obtained by mixing the polymer (A) and the copolymer (B), the mixing method is not particularly limited. For example, the compound and pellets are mixed by dry blending with a twin screw extruder. And the like.

[Thermoplastic elastomer (Y)]
When the expandable base film of the present invention contains a thermoplastic elastomer (Y), the thermoplastic elastomer (Y) is mixed with the expandable base film of the present invention itself, that is, at least the composition (X) described above. The melting point TmY2 measured by a differential scanning calorimeter (DSC) is 200 ° C. or less, or substantially no melting point TmY2 is observed, or the thermoplastic elastomer (Y) itself is a scanning calorimeter. It is desirable that the melting point TmY1 measured by (DSC) is 200 ° C. or lower or that the melting point TmY1 is not substantially observed.

  By adjusting the melting point TmY1 or the melting point TmY2 lower than the temperature at the time of heat sealing described later, or by using a thermoplastic elastomer having no melting point, that is, a low crystalline and thermoplastic elastomer, Thus, it is considered that the expandability can be improved without impairing the heat resistance by forming an alloy structure (also referred to as a phase dispersion structure) in which the thermoplastic elastomer (Y) and the composition (X) are finely dispersed.

  The melting point TmY1 of the thermoplastic elastomer (Y) alone and the melting point TmY2 of the thermoplastic elastomer (Y) in the film are usually almost the same, but the component (in the present invention, the composition ( When the crystallinity of X) is high, the melting point of the thermoplastic elastomer (Y) itself may change due to the influence of the crystal component. Even if a thermoplastic elastomer (Y) having no melting point alone is used, the melting point TmY2 in the film may be observed. That is, in the present invention, by using a thermoplastic elastomer (Y) having a melting point TmY1 of 200 ° C. or lower or a melting point TmY1 substantially not observed, a film having a melting point TmY2 of 200 ° C. or lower or substantially no melting point TmY2 is obtained. be able to.

  From the viewpoint of obtaining a film that is difficult to neck, it is preferable to use a thermoplastic elastomer (Y) having a melting point TmY1 of 105 ° C. or higher and 200 ° C. or lower, and a thermoplastic resin having a melting point TmY1 of 110 ° C. or higher and 180 ° C. or lower. It is more preferable to use an elastomer (Y). Similarly, from the viewpoint of obtaining a film that is difficult to neck, the melting point TmY2 is preferably 105 ° C. or higher and 200 ° C. or lower, and more preferably 110 ° C. or higher and 180 ° C. or lower.

  The thermoplastic elastomer (Y) 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., there is a concern that physical properties such as extensibility of the film after molding are likely to change depending on storage conditions.

  The thermoplastic elastomer (Y) is not particularly limited as long as it is a thermoplastic elastomer having the above melting point, and specific examples include olefin elastomers and styrene elastomers.

  Specific examples of the olefin elastomer include a propylene / α-olefin copolymer, that is, a copolymer of propylene and an α-olefin other than propylene. The α-olefin in the propylene / α-olefin copolymer 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 may be one type or a combination of two or more types. The propylene / α-olefin copolymer is more preferably a propylene / 1-butene / ethylene copolymer. The content of the structural unit derived from propylene of the propylene / α-olefin copolymer is preferably 50 mol% or more, more preferably 60 mol% or more, from the viewpoint of obtaining good moldability.

  The styrene elastomer is composed of polystyrene as a hard segment and polybutadiene, polyisoprene, a copolymer of polybutadiene and polyisoprene, or a hydrogenated product thereof as soft segments. Hydrogenation may be performed only on a part of polybutadiene or polyisoprene, or all may be hydrogenated. Such styrenic elastomers can be imparted with good adhesion by being modified with functional groups such as carboxylic acid groups, acid anhydride groups, amino groups, epoxy groups and hydroxyl groups. Commercially available modified styrene elastomers include “Tuftec” (manufactured by Asahi Kasei Chemicals, registered trademark), “Clayton” (manufactured by Kraton Polymer Japan, registered trademark), “Dynalon” (manufactured by JSR, registered trademark), “ Septon "(manufactured by Kuraray Co., Ltd., registered trademark)," SIBSTER "(manufactured by Kaneka Corporation, registered trademark), and the like.

  Among these, as the thermoplastic elastomer (Y) in which the melting point TmY1 is 105 ° C. or more and 200 ° C. or less and the melting point TmY2 is 105 ° C. or more and 200 ° C. or less, for example, “Tafmer” (manufactured by Mitsui Chemicals, Registered trademark), “NOTIO” (registered trademark) manufactured by Mitsui Chemicals, and “Vistamaxx” (registered trademark manufactured by ExxonMobil Chemical).

  Olefin-based elastomers and styrene-based elastomers can be obtained by copolymerizing monomers (monomers) constituting the elastomer in the presence of a conventionally known production method, for example, a Ziegler-Natta catalyst or a metallocene-based catalyst. Specifically, the propylene / α-olefin copolymer can be obtained by copolymerizing propylene and an α-olefin other than propylene.

  The tensile elastic modulus at 23 ° C. measured in accordance with JIS K7127 (1999) of the thermoplastic elastomer (Y) is preferably 1 MPa or more and 1500 MPa or less, and more preferably 3 MPa or more and 1400 MPa or less. When the tensile elastic modulus is in the above range, the handling property of the film is improved as compared with the case where the tensile modulus is smaller than the above range, and the flexibility of the film is improved as compared with the case where it is larger than the above range. The material film is difficult to tear.

The density of the thermoplastic elastomer (Y) measured in accordance with JIS K7112 (density gradient tube method) is preferably 850 kg / m ³ or more and 900 kg / m ³ or less, and 860 kg / m ³ or more and 900 kg / m ^3. The following is more preferable.
When the density is in the above range, the flexibility is excellent compared to the case where the density is larger than the above range, and the pellet handling property is excellent compared to the case where the density is smaller than the above range.

  The melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg in accordance with ASTM D1238 of the thermoplastic elastomer (Y) is easily mixed with the composition (X) in the extruder and can be coextruded. If it is, it will not specifically limit. The melt flow rate (MFR) of the thermoplastic elastomer (Y) is preferably 1 g / 10 min to 50 g / 10 min, more preferably 3 g / 10 min to 40 g / 10 min. If MFR is in the above range, it is easy to extrude to a relatively uniform film thickness.

  The content of the thermoplastic elastomer (Y) contained in the expandable substrate film of the present invention is 3 parts by mass or more and 50 parts by mass with respect to 100 parts by mass in total of the composition (X) and the thermoplastic elastomer (Y). Preferably, it is preferably 5 parts by mass or more and 40 parts by mass or less. By including the composition (X) and the thermoplastic elastomer (Y) at the above ratio, the component of the composition (X) and the component of the thermoplastic elastomer (Y) are appropriately phase-dispersed. When the expandable substrate film of the present invention is used as a material layer, high and uniform expandability can be imparted without greatly impairing heat resistance.

[Other ingredients]
The expandable base film of the present invention may contain other components other than the composition (X) and the thermoplastic elastomer (Y) as necessary.
However, the total amount of the composition (X) and the thermoplastic elastomer (Y) is preferably 80% by mass or more based on the total amount of the expandable substrate film of the present invention from the viewpoint of more effectively achieving the effects of the present invention. 90 mass% or more is more preferable, and 100 mass% is most preferable. That is, it is preferable that the expandable substrate film substantially consists of the composition (X) and the thermoplastic elastomer (Y).
Examples of the other components include other resins such as polyethylene, polypropylene, and polybutene, and additives such as a heat stabilizer, a weather stabilizer, a rust inhibitor, a copper damage stabilizer, and an antistatic agent. Etc.

[Method for producing expandable substrate film]
The expandable substrate film of the present invention can be produced by any method, but the composition (X) containing the polymer (A) and the copolymer (B), and a differential scanning calorimeter (DSC) And a thermoplastic elastomer (Y) in which the melting point TmY1 is 160 ° C. or less or the melting point TmY1 is not substantially observed, and the content of the thermoplastic elastomer (Y) is the composition (X) and the above It is preferable to manufacture by the manufacturing method including the process of shape | molding the melt-kneaded material which is 3 to 50 mass parts with respect to a total of 100 mass parts with a thermoplastic elastomer (Y).
Specific film forming methods include, for example: 1) Melting and kneading the pellets of the composition (X) and the pellets of the thermoplastic elastomer (Y) with an extruder and extrusion molding to produce an expandable substrate film (Dry blend method); 2) Melt-knead the composition (X) and the thermoplastic elastomer (Y) with a twin-screw extruder, etc. A method of producing an expandable substrate film by extrusion molding (melt blend method); 3) A melt blend resin obtained by melt-kneading the composition (X) and the thermoplastic elastomer (Y) with an extruder or the like, There is a method of pressing to a predetermined thickness with a press machine (press film method).

  When the expandable substrate film is produced by the extrusion molding of 1) and 2), the extrusion temperature is a temperature at which the composition (X) and the thermoplastic elastomer (Y) are uniformly kneaded and can be molded to a uniform thickness. What is necessary is just to be about 230-290 degreeC, for example. Extrusion molding can be performed by a known extruder having, for example, a T die or an inflation die.

  When an expandable substrate film is produced by press molding in the above 3), the pressing conditions are set to conditions that allow the composition (X) and the thermoplastic elastomer (Y) to be melted and molded into a sheet having a uniform thickness. Just do it. The press temperature can be set to, for example, about 230 to 290 ° C. Press molding can be performed with a known press.

[Characteristics of expandable base film]
The thickness of the expandable substrate film of the present invention is preferably 20 μm to 350 μm, more preferably 30 μm to 300 μm, and still more preferably 50 μm to 250 μm. If the thickness of the expandable substrate film of the present invention is within the above range, the handleability is easy.

The tensile elastic modulus of the expandable substrate film is preferably 300 MPa or more and 2000 MPa or less, and more preferably 500 MPa or more and 1500 MPa or less. When the tensile modulus of elasticity of the expandable substrate film is in the above range, the expandable substrate film can be easily expanded as compared with the case where the tensile elastic modulus is higher than the above range, and the expandable substrate as compared with the case where it is lower than the above range. The strength of the film is improved.
In addition, in this invention, the tensile elasticity modulus of an expandable base film refers to the value measured based on JISK7127 (1999) on the conditions of measurement temperature 23 degreeC.

The expandable substrate film of the present invention preferably has reduced anisotropy in tensile modulus. More preferably, it is satisfy | filling following formula (1).
0.5 ≦ YM _MD / YM _TD ≦ 1.5 (1)
[In Formula (1), YM _MD shows the tensile elasticity modulus of MD direction, and YM _TD shows the tensile elasticity modulus of TD direction. ]

  Here, the “MD direction” (Machine Direction) refers to the film flow direction, and the “TD direction” (Transverse Direction) refers to a direction perpendicular to the MD direction and parallel to the main surface of the film.

The lower limit of YM _MD / YM _TD is preferably 0.6, and more preferably 0.7.
The upper limit of YM _MD / YM _TD is preferably 1.4, and more preferably 1.3.

Moreover, it is preferable that the expandable base film of the present invention has reduced anisotropy of tensile elongation at break. More preferably, it is satisfy | filling following formula (2).
0.5 ≦ EL _MD / EL _TD ≦ 1.5 (2)
Wherein (2), _{EL MD} represents the tensile elongation at break in the MD direction, _{EL TD} indicates a tensile elongation at break in the TD direction. ]
In the present invention, the tensile elongation at break refers to a value measured according to JIS K7127 (1999) under the condition of a measurement temperature of 23 ° C.

The lower limit of EL _MD / EL _TD is preferably 0.5, and more preferably 0.7.
The upper limit of EL _MD / EL _TD is preferably 1.4, and more preferably 1.3.
The EL _MD is preferably 300% to 800%, and more preferably 400% to 700%.
When the EL _MD is 300% or more, the expandable film can be easily expanded.
When the EL _MD is 800% or less, the handleability of the expandable film is more excellent.
The preferred range of EL _{TD is the same as} the preferred range of EL _MD .

Moreover, it is preferable that the expandable base film of the present invention has reduced tear strength anisotropy. More preferably, it is satisfy | filling following formula (3).
0.4 <= _SMD / _STD <= 1.5 ... Formula (3)
Wherein _{(3), S MD} represents the Elmendorf tear strength in the MD _{direction, S TD} shows Elmendorf tear strength in the TD direction. ]
In addition, in this invention, Elmendorf tear strength points out the value measured based on JISK7128-2 (1998) on the conditions of measurement temperature 23 degreeC.

The lower limit of S _MD / S _TD is preferably 0.4, and more preferably 0.5.
The upper limit of S _MD / S _TD is preferably 1.4, and more preferably 1.3.
S _MD is preferably 50N / cm~1100N / cm, more preferably 100N / cm~1100N / cm, particularly preferably 300N / cm~1100N / cm.
When the _SMD is 50 N / cm or more, the strength of the expandable film is further improved.
When S _MD is less than 1100 N / cm, excellent in handling property of the extended film.
The preferable range of _{STD is the same as} the preferable range of _SMD .

[Application of expandable base film]
As described above, the expandable base film of the present invention is suitable as a base film for a dicing film that is adhered to a semiconductor substrate before dicing the semiconductor substrate in the method for manufacturing a semiconductor device.
The expandable base film of the present invention is also suitable as other protective films other than the dicing film.
Other protective films include, for example, semiconductor surface protective films that are adhered to a semiconductor substrate before grinding the semiconductor substrate in the method of manufacturing a semiconductor device, various resin products such as building materials and optical components, metal products, For the purpose of preventing scratches and dust-proofing during transportation, storage and processing of glass products and the like, there are protective films that are attached to these surfaces.

[Expandable adhesive film]
The expandable adhesive film of the present invention includes at least a base material layer made of the expandable base film of the present invention described above and an adhesive layer. The base material layer and the pressure-sensitive adhesive layer may each be a multilayer, and the respective layers may be bonded with an adhesive resin or the like.

(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-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives, styrene-based elastomers and olefins. You may be comprised with thermoplastic adhesive materials, such as an elastomer. Furthermore, 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 strength by heating, or the like. A preferable example of the radiation curable pressure sensitive adhesive includes an ultraviolet curable pressure sensitive adhesive. Moreover, when using the expandable adhesive film of this invention as a dicing film, the adhesive layer of Unexamined-Japanese-Patent No. 2005-277297 can also be used.

  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 ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate. Examples of comonomer constituting the acrylic copolymer include vinyl acetate, acrylonitrile, acrylamide, styrene, methyl methacrylate, methyl acrylate, methacrylic acid, acrylic acid, itaconic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, dimethylamino Examples include ethyl methacrylate, acrylic amide, methylol acrylic amide, glycidyl methacrylate and maleic anhydride.

  Examples of rubber adhesives include natural rubber, synthetic isoprene rubber, styrene butadiene rubber, styrene / butadiene block copolymer, styrene / isoprene block copolymer, styrene / isobutylene copolymer, butyl rubber, polyisobutylene, polybutadiene, Polyvinyl ether, silicone rubber, chloroprene rubber and the like are included.

  A tackifier resin may be further added to the rubber-based pressure-sensitive adhesive in order to increase the adhesive strength. Examples of tackifying resins include rosin resins and terpene resins, and are preferably terpene resins from the viewpoint of good compatibility with rubber adhesives. Examples of rosin resins include rosin, polymerized rosin, hydrogenated rosin, rosin ester, etc .; examples of terpene resins include terpene resins, terpene phenol resins, aromatic modified terpene resins and rosin phenol resins, etc. Is included. It is preferable that content of tackifying resin is 5 mass parts-100 mass parts with respect to 100 mass parts of rubber-type adhesives.

  The ultraviolet curable pressure-sensitive adhesive and the heat-curable pressure-sensitive adhesive are a pressure-sensitive adhesive such as the acrylic pressure-sensitive adhesive, a curable compound (a component having a carbon-carbon double bond), a photopolymerization initiator or a thermal polymerization initiator, ,including.

  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 Esters of (meth) acrylic acid and polyhydric alcohols such as pentyl glycol di (meth) acrylate and dipentaerythritol hexa (meth) acrylate; ester acrylate oligomers; 2-propenyl di-3-butenyl cyanurate, 2-hydroxyethyl Examples include isocyanurates or isocyanurate compounds such as bis (2-acryloxyethyl) isocyanurate and tris (2-methacryloxyethyl) isocyanurate. In addition, when an adhesive is an ultraviolet curable polymer which has a carbon-carbon double bond in the side chain of a polymer, it is not necessary to add a sclerosing | hardenable compound.

  5-900 mass parts is preferable with respect to 100 mass parts of adhesives, and, as for content of a curable compound, 20-200 mass parts is more preferable. When the content of the curable compound is within the above range, it becomes easier to adjust the adhesive force than when the content is less than the above range, and the sensitivity to heat and light is too high compared to the case where the content is larger than the above range. The storage stability is less likely to deteriorate.

  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; benzyl, benzoin, benzophenone, α -Aromatic ketones such as hydroxycyclohexyl phenyl ketone; aromatic ketals such as benzyldimethyl ketal; polyvinyl benzophenone; thioxanthones such as chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, and diethylthioxanthone.

  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 thermal polymerization initiator include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxyester, peroxydicarbonate, and the like.

  You may add a crosslinking agent to an adhesive. As cross-linking agents, epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether; tetramethylolmethane-tri-β-aziridinylpropionate, trimethylol Propane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N, N′-hexamethylene-1,6-bis (1- Aziridine-based compounds such as aziridinecarboxyamide); isocyanate-based compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, and polyisocyanate.

  The pressure-sensitive adhesive layer is adhered to the surface of a SUS-304-BA plate and allowed to stand for 60 minutes, and then peeled off from the surface of the SUS-304-BA plate, measured in accordance with JIS Z0237. Is preferably 0.1 N / 25 mm to 10 N / 25 mm. Due to the adhesive force being in the above range, damage to the semiconductor substrate and the remaining adhesive layer when the dicing film is peeled off from the semiconductor substrate compared to the case where the adhesive force is higher than the above range are suppressed, compared to the case where the adhesive force is lower than the above range. Good adhesion to the semiconductor substrate is ensured.

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 adhesive strength is more preferably 0.1 N / 25 mm to 5 N / 25 mm, and still more preferably 0.1 N / 25 mm to 3 N / 25 mm.
In addition, when the adhesive contained in the adhesive layer has an adhesive force switching function such as a radiation curable type, a thermosetting type, and a heat foaming type, after the adhesive force is switched and reduced by radiation irradiation, etc. The adhesive strength is preferably within the above range.

  Although the thickness of an adhesive layer is not specifically limited, It is preferable that it is 3-100 micrometers, and it is more preferable that it is 10-100 micrometers. When the thickness of the pressure-sensitive adhesive layer is within the above range, sufficient adhesiveness can be obtained, and the effect of the expandable substrate film of the present invention is hardly impaired.

[Structure and properties of expandable adhesive film]
As described above, the expandable adhesive film includes at least the base material layer and the adhesive layer, and may further include other layers.
In addition, when using an expandable adhesive film for a dicing film, a dicing film is stuck on a semiconductor substrate by making the adhesive layer of an expandable adhesive film contact a semiconductor substrate directly. Therefore, the pressure-sensitive adhesive layer is desirably provided on the outermost surface of the expandable pressure-sensitive adhesive film.

  The total thickness of the expandable adhesive film is preferably 50 to 200 μm, and more preferably 70 to 150 μm.

[Dicing film]
The dicing film of the present invention includes at least the expandable adhesive film of the present invention described above.
In addition, as above-mentioned, since the dicing film of this invention sticks the adhesive layer of an expandable adhesive film on a semiconductor substrate, it is preferable that the said adhesive layer is an outermost surface layer. However, the dicing film of the present invention may include a release film for protecting the surface of the pressure-sensitive adhesive layer (sometimes referred to as a release liner or a separator) on the surface of the pressure-sensitive adhesive layer as necessary. . When using a dicing film provided with a release film, for example, the release film was removed before the dicing film was attached to the semiconductor substrate, and the release film was removed so that the exposed adhesive layer and the semiconductor substrate were in contact with each other. A dicing film is attached to a semiconductor substrate.
Examples of the material for the release film include synthetic resin films such as paper, polyethylene, polypropylene, and polyethylene terephthalate. The thickness of a peeling film is about 10-200 micrometers normally, Preferably it is about 25-100 micrometers.

The dicing film of the present invention may further include a low friction layer on the surface opposite to the surface on which the pressure-sensitive adhesive layer is formed in the base material layer of the expandable pressure-sensitive adhesive film, if necessary.
That is, when the dicing film is used as a dicing film for semiconductors, as a method of expanding the dicing film, the peripheral portion of the dicing film is fixed with a ring frame, and the stage of the expander is moved from the lower center of the dicing film. There is a method of pushing up (see FIG. 1 described later). At this time, if the friction of the surface of the dicing film on the side in contact with the stage is large, the film is difficult to slide on the stage, and the film portion in contact with the stage cannot be expanded. For this reason, reducing the friction of the surface of the dicing film on the side in contact with the stage; that is, by arranging a low friction layer, the expansion machine stage can be made slippery and the entire surface of the dicing film can be expanded uniformly. it can.

  Such a low friction layer is made of a resin such as polyethylene or ethylene ionomer resin. Further, a lubricant may be applied or contained on the surface of the low friction layer in order to further improve the slipperiness as necessary. Examples of such lubricants include lubricants such as erucic acid amide, oleic acid amide, and silicone oil, and master batches thereof (lubricant master batch).

  The total thickness of the dicing film is preferably 50 to 200 μm, and more preferably 70 to 150 μm.

The dicing film preferably has a tensile elastic modulus (initial elastic modulus) at 23 ° C. of 70 MPa or more. When the tensile elastic modulus is in the above range, the handling property deterioration such as the dicing film becoming wrinkles when the dicing film is adhered to the semiconductor substrate is suppressed as compared with the case where the tensile modulus is lower than the above range.
In addition, in this invention, the tensile elasticity modulus of a dicing film points out the value measured based on JISK7127 (1999) on the conditions of measurement temperature 23 degreeC.

[Method of manufacturing dicing film]
There is no limitation in particular in the manufacturing method of the dicing film of this invention, A well-known method can be used.

As a manufacturing method of the dicing film of the present invention, for example, a pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive coating liquid (pressure-sensitive adhesive solution, emulsion liquid, etc.) containing the above-mentioned pressure-sensitive adhesive on the base material layer and drying it. The method of forming is mentioned.
The application can be performed using a known apparatus such as a roll coater, a comma coater, a die coater, a Mayer bar coater, a reverse roll coater, or a gravure coater.
The drying conditions for drying the pressure-sensitive adhesive coating solution are not particularly limited, and in general, it is preferably dried for 10 seconds to 10 minutes in a temperature range of 80 ° C to 300 ° C. It is more preferable to dry for 15 seconds to 5 minutes in a temperature range of from ° C to 200 ° C. Further, after the drying of the pressure-sensitive adhesive coating solution, the dicing film may be heated at 40 to 80 ° C. for about 5 to 300 hours.
Moreover, it is also preferable to stick a release film on the pressure-sensitive adhesive layer surface after forming the pressure-sensitive adhesive layer.

  As a manufacturing method of the dicing film of the present invention, for example, the pressure-sensitive adhesive layer is formed after the pressure-sensitive adhesive coating solution is applied to one surface of the release film by the above-described method and dried to form the pressure-sensitive adhesive layer. A method of laminating the peeled film and the base material layer by a dry laminating method or the like so that the pressure-sensitive adhesive layer and the base material layer face each other is also included. In this method, after lamination, the release film may be left as it is or may be removed.

  In the manufacturing method of the dicing film of the present invention, from the viewpoint of preventing contamination of the semiconductor substrate, all film forming environments such as the base material layer and the adhesive layer, and the manufacturing environment of these raw materials are in US Federal Standard 209b. It is preferable that the cleanliness is maintained at a specified class 1,000 or less.

[Method for Manufacturing Semiconductor Device]
The manufacturing method of the semiconductor device of the present invention includes a bonding step of bonding the dicing film of the present invention described above to a semiconductor substrate so that the surface of the semiconductor substrate and the adhesive layer are in contact with each other, and the dicing film A dicing step of dicing the semiconductor substrate to which is adhered, an expansion step of obtaining a plurality of semiconductor chips separated from each other by expanding the dicing film after the dicing step, and at least one of the plurality of semiconductor chips A pick-up process for picking up one of the two. The semiconductor device manufacturing method of the present invention may have other steps.
In addition, when using the semiconductor substrate which has a circuit surface only in one surface, the surface of the semiconductor substrate which contacts the said adhesive layer in a sticking process is not specifically limited, On the surface on the opposite side to the said circuit surface in a semiconductor substrate It is preferable to stick the pressure-sensitive adhesive layer in contact.

  In the method for manufacturing a semiconductor device of the present invention, the dicing film of the present invention including the expandable base film of the present invention having high and uniform expandability that is difficult to neck is used. For this reason, especially when expanding a dicing film in an expansion process, a dicing film can be expanded isotropically, suppressing a fracture | rupture and a tear of a dicing film, and a dicing film is hard to neck. Thereby, when the adhesion force between the dicing film and the semiconductor chip is reduced by the expansion, the variation in adhesion force between the plurality of semiconductor chips can be reduced, so that the semiconductor chip is picked up and peeled off from the dicing film. Workability is improved. In addition, since the dicing film can be expanded isotropically, the interval between the plurality of semiconductor chips can be easily increased uniformly, so that the workability when picking up the semiconductor chips is improved.

  Hereafter, each process of the manufacturing method of the semiconductor device of this invention is demonstrated.

<Adhesion process>
The adhering step is a step of adhering the dicing film of the present invention described above to a semiconductor substrate so that the surface of the semiconductor substrate and the adhesive layer face each other.
Examples of the semiconductor substrate include a substrate (for example, a wafer) of silicon, germanium, gallium-arsenic, gallium-phosphorus, gallium-arsenic-aluminum, or the like.
As the semiconductor substrate, a semiconductor substrate having a circuit formed on the surface is preferably used. In this case, it is preferable to attach a dicing film to the semiconductor substrate so that the circuit forming surface on which the circuit is formed and the adhesive layer are in contact with each other.

  The sticking may be performed manually, but is usually performed by an automatic sticking machine equipped with a roll-shaped surface protective film. As an automatic pasting machine, for example, Takatori Co., Ltd., model: ATM-1000B, ATM-1100, TEAM-100, Teikoku Seiki Co., Ltd., model: STL series, Nitto Seiki Co., Ltd., model : DR-8500II, DR-3000II and the like.

Although there is no restriction | limiting in particular in the temperature of the dicing film at the time of sticking and a semiconductor substrate, 40 to 80 degreeC is preferable.
When the temperature is 40 ° C. or higher, the adhesion between the semiconductor substrate and the dicing film is further improved. Moreover, since the dicing film of this invention is equipped with the expandable base film of this invention excellent in heat resistance, even when the temperature of a dicing film is 40 degreeC or more, deterioration of a expandable base film is suppressed. .
Moreover, deterioration of an expandable base film is suppressed more as the said temperature is 80 degrees C or less.

Moreover, although there is no restriction | limiting in particular about the pressure of the dicing film and semiconductor substrate at the time of sticking, 0.3 MPa-0.5 MPa are preferable.
When the pressure is 0.3 MPa or more, the adhesion between the semiconductor substrate and the dicing film is further improved. Moreover, since the dicing film of this invention is equipped with the expandable base film of this invention excellent in stress relaxation property, even when the said pressure is 0.3 Mpa or more, the curvature etc. of a semiconductor substrate are suppressed.
When the pressure is 0.5 MPa or less, warpage of the semiconductor substrate and the like are further suppressed.

<Dicing process>
The dicing process is a process of dicing the semiconductor substrate to which the dicing film is attached.
In this "dicing"
(A) An operation of dividing a semiconductor substrate by providing a cut with the same depth as the thickness of the semiconductor substrate to obtain a plurality of semiconductor chips (hereinafter also referred to as “full cut dicing”),
(B) an operation of providing a cut with a depth less than the thickness of the semiconductor substrate (hereinafter also referred to as “half-cut dicing”), and
(C) An operation (hereinafter also referred to as “stealth dicing”) of providing a modified region that does not reach the cutting of the semiconductor substrate by irradiating the semiconductor substrate with laser light or plasma is included.
The dicing can be performed using a dicing blade (dicing saw), laser light, plasma, or the like.
With respect to the method of manufacturing a semiconductor device by full cut dicing, for example, Japanese Patent Application Laid-Open No. 2012-188597 (particularly, paragraphs 0072 to 0076 and FIGS. 3A to 3E) and Japanese Patent No. 494514 (particularly, paragraphs 0091 to 0103). 4A to 4E and FIGS. 5A to 5E) can be referred to as appropriate.

  When the dicing is full cut dicing, the semiconductor substrate is divided into a plurality of semiconductor chips by dicing. In this case, in the expansion step, the interval between the plurality of semiconductor chips is expanded (that is, the plurality of semiconductor chips are separated).

  On the other hand, when the dicing is half-cut dicing and stealth dicing, the semiconductor substrate is not divided into a plurality of semiconductor chips only by dicing, and the semiconductor substrate is divided by expansion of the dicing film after dicing. Thus, a plurality of semiconductor chips can be obtained. In this case, in the expansion step, both the division of the semiconductor substrate into a plurality of semiconductor chips and the expansion of the interval between the plurality of semiconductor chips (that is, the separation of the plurality of semiconductor chips) are performed.

  When dicing is any of full cut dicing, half cut dicing, and stealth dicing, the dicing film is still expanded after dicing. For this reason, in any case, the effects of the semiconductor device manufacturing method of the present invention described above are exhibited.

<Expansion process>
The expansion step is a step of obtaining a plurality of semiconductor chips separated from each other by expanding the dicing film after the dicing step.
By this step, the interval between the plurality of semiconductor chips can be increased. Moreover, by this process, shear stress arises between the adhesive layer of a dicing film and a semiconductor chip, and the adhesive force of a semiconductor chip and a dicing film falls by this shear stress.
In this step, for these reasons, the semiconductor chip can be easily picked up in a later pickup step.

As a method of expanding the dicing film, at least the operation of the expansion process is performed on an expansion machine provided with a stage for placing a semiconductor substrate on which the dicing film is stuck, and the expansion machine below the dicing film There is a method of expanding by raising the stage.
Moreover, as a method of expanding the dicing film, a method of pulling (expanding) in a direction parallel to the film surface can also be mentioned.

<Pickup process>
The pickup process is a process of picking up at least one of the plurality of semiconductor chips.
By this pickup, at least one of the plurality of semiconductor chips can be peeled from the dicing film.
The pickup can be performed by a known method.

<Other processes>
The method for manufacturing a semiconductor device of the present invention may have other steps other than those described above.
As other steps, known steps can be used in the method of manufacturing a semiconductor device.

When a semiconductor substrate having a circuit surface on only one surface is used as the semiconductor substrate, the semiconductor substrate may further include a sealing step for sealing the circuit surface of the semiconductor substrate.
In the sealing step, for example, the circuit surface is sealed inside by forming a protective layer on the circuit surface of the semiconductor substrate to which the dicing film is bonded in the bonding step. In that case, the semiconductor substrate whose circuit surface is sealed is diced by a dicing process after the sealing process.
In addition, a sealing process may be performed before a sticking process.

When a semiconductor substrate having a circuit surface is used, for example, electrode formation (bonding) and resin sealing (baking) by a method usually used for the circuit formation surface of the semiconductor substrate after the adhering step and before the dicing step. You may have further the process of performing. This manufacturing method provided with the steps of electrode formation and resin sealing is also called WLP (Wafer Level Package). Since the expandable substrate film of the present invention is excellent in heat resistance, it can be suitably used for WLP (Wafer Level Package).
Regarding the sealing step and WLP (Wafer Level Package), for example, the descriptions in Japanese Patent Application Laid-Open Nos. 2008-16539 and 2012-188597 can be appropriately referred to.

The method for manufacturing a semiconductor device of the present invention may further include a grinding step for grinding the semiconductor substrate after the attaching step and before the expanding step.
When the manufacturing method of the semiconductor device of the present invention includes a grinding step, the adhering step includes, for example, the dicing film on the circuit forming surface of the semiconductor substrate on which the circuit is formed only on one surface, and the circuit forming surface. And the pressure-sensitive adhesive layer are in contact with each other, and the grinding step is preferably a step of grinding the non-circuit-formed surface of the semiconductor substrate. In this case, the dicing film has a function as a semiconductor surface protective film.
The grinding process may be provided either before or after the dicing process.

The grinding can be performed by a known method such as a through-feed method or an in-feed method. In either method, the semiconductor substrate is ground with a grindstone.
The temperature of the semiconductor substrate at the start of the grinding process is usually about 18 ° C. to 28 ° C., preferably 20 ° C. to 25 ° C. Further, the temperature of the semiconductor substrate during the grinding process depends on the material of the substrate to be ground, but is usually 20 ° C to 120 ° C, preferably 30 ° C to 80 ° C,
It is more preferable that it is 40 to 70 degreeC.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

[Polymer (A)]
The polymer A-1 shown in Table 1 was used as the polymer (A).
Moreover, the following measurements were performed about the polymer A-1. Measurement methods for various physical properties of the polymer are shown below, and the measurement results are shown in Table 1.
In addition, as for the structural unit (AQ) in the polymer A-1, a structural unit derived from 1-hexadecene and 1-octadecene are mixed.

1) Composition The composition of the polymer was determined by the measurement method using ¹³ C-NMR.
2) Tensile modulus (23 ° C)
The elastic modulus of the film was measured according to JIS K7127 (1999).
3) Intrinsic viscosity [η]
Using an Ubbelohde viscometer, the intrinsic viscosity [η] measured at 135 ° C. in a decalin solvent was determined by the above method. 4) Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)
The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) were determined by a standard polystyrene conversion method using the gel permeation chromatography (GPC).
5) Melt flow rate (MFR)
By the said method, the melt flow rate (MFR) measured by 260 degreeC and a 5-kg load was calculated | required based on ASTMD1238.
6) Density Density was determined according to JIS K7112 (density gradient tube method).
7) Melting point (Tm)
It measured by the said method based on JISK7121, and calculated | required from the peak temperature.

[Copolymer (B)]
<Synthesis Example 1> Synthesis of Polymer B-1 (Copolymer (B)) Into a SUS autoclave with a stirring blade with a capacity of 1.5 L which was sufficiently substituted with nitrogen, 300 ml of n-hexane (under a dry nitrogen atmosphere, Dried on activated alumina) and 450 ml of 4-methyl-1-pentene at 23 ° C., and then charged with 0.75 ml of a 1.0 mmol / ml toluene solution of triisobutylaluminum (TIBAL), The stirrer was turned.
Next, the autoclave was heated to an internal temperature of 60 ° C. and pressurized with propylene so that the total pressure (gauge pressure) was 0.40 MPa.
Subsequently, 1 mmol of methylaluminoxane and 0.01 mmol of diphenylmethylene (1-ethyl-3-t-butyl-cyclopentadienyl) (2,7-di-t-) prepared in advance were converted into Al. 0.34 ml of a toluene solution containing (butyl-fluorenyl) zirconium dichloride was pressed into the autoclave with nitrogen to initiate the polymerization reaction. During the polymerization reaction, the temperature was adjusted so that the internal temperature of the autoclave was 60 ° C.
Sixty minutes after the start of the polymerization, 5 ml of methanol was pressed into the autoclave with nitrogen to stop the polymerization reaction, and then the inside of the autoclave was depressurized to the atmospheric pressure. After depressurization, acetone was added to the reaction solution while stirring the reaction solution to obtain a polymerization reaction product containing a solvent. Subsequently, the polymerization reaction product containing the obtained solvent was dried at 130 ° C. under reduced pressure for 12 hours to obtain 36.9 g of a powdery polymer B-1 as a copolymer (B).

<Synthesis Example 2> Synthesis of Polymer B-2 (Copolymer (B)) Into a SUS autoclave with a stirring blade with a capacity of 1.5 L that was sufficiently substituted with nitrogen, 300 ml of n-hexane (under a dry nitrogen atmosphere, Dried on activated alumina) and 450 ml of 4-methyl-1-pentene at 23 ° C., and then charged with 0.75 ml of a 1.0 mmol / ml toluene solution of triisobutylaluminum (TIBAL), The stirrer was turned.
Next, the autoclave was heated until the internal temperature reached 60 ° C., and pressurized with propylene so that the total pressure (gauge pressure) was 0.19 MPa.
Subsequently, 1 mmol of methylaluminoxane and 0.01 mmol of diphenylmethylene (1-ethyl-3-t-butyl-cyclopentadienyl) (2,7-di-t-) prepared in advance were converted into Al. 0.34 ml of a toluene solution containing (butyl-fluorenyl) zirconium dichloride was pressed into the autoclave with nitrogen to initiate the polymerization reaction. During the polymerization reaction, the temperature was adjusted so that the internal temperature of the autoclave was 60 ° C.
Sixty minutes after the start of the polymerization, 5 ml of methanol was pressed into the autoclave with nitrogen to stop the polymerization reaction, and then the inside of the autoclave was depressurized to the atmospheric pressure. After depressurization, acetone was added to the reaction solution while stirring the reaction solution to obtain a polymerization reaction product containing a solvent. Subsequently, the polymerization reaction product containing the obtained solvent was dried at 130 ° C. under reduced pressure for 12 hours to obtain 44.0 g of a powdery polymer B-2 as a copolymer (B).

<Synthesis Example 3> Synthesis of Polymer B-3 After charging 750 ml of 4-methyl-1-pentene at 23 ° C. into a SUS autoclave with a stirring blade with a capacity of 1.5 L which was sufficiently purged with nitrogen, 0.75 ml of a 1.0 mmol / ml toluene solution of isobutylaluminum (TIBAL) was charged, and the stirrer was rotated.
Next, the autoclave was heated until the internal temperature reached 60 ° C., and pressurized with propylene so that the total pressure (gauge pressure) was 0.15 MPa.
Subsequently, 1 mmol of methylaluminoxane and 0.005 mmol of diphenylmethylene (1-ethyl-3-t-butyl-cyclopentadienyl) (2,7-di-t-) prepared in advance were converted into Al. 0.34 ml of a toluene solution containing (butyl-fluorenyl) zirconium dichloride was pressed into the autoclave with nitrogen to initiate the polymerization reaction. During the polymerization reaction, the temperature was adjusted so that the internal temperature of the autoclave was 60 ° C.
Sixty minutes after the start of the polymerization, 5 ml of methanol was pressed into the autoclave with nitrogen to stop the polymerization reaction, and then the inside of the autoclave was depressurized to the atmospheric pressure. After depressurization, acetone was added to the reaction solution while stirring the reaction solution to obtain a polymerization reaction product containing a solvent. Subsequently, the polymerization reaction product containing the obtained solvent was dried under reduced pressure at 130 ° C. for 12 hours to obtain 45.9 g of a powdery polymer A-3.

Table 2 shows the measurement results of various physical properties of the obtained polymer B-1 to polymer B-3.
1) Composition, 2) Tensile modulus (23 ° C.), 3) Intrinsic viscosity [η], 4) Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn), 6) Density, and 7) Melting point ( Tm) was measured by the same method as described above.
The melt flow rate (MFR) was measured at 230 ° C. and a 2.16 kg load in accordance with ASTM D1238 as described above.

[Composition (X)]
<Preparation of composition X>
95 parts by mass of the polymer A-1 and 5 parts by mass of the polymer B-1 were mixed with a twin screw extruder manufactured by Thermo Plastics Co., thereby obtaining a composition X1.
A composition X2 to a composition X3 were obtained in the same manner as the composition X1, except that the mass ratio [A / B] of the polymer A-1 and the polymer B-1 was as shown in Table 3. . In addition, "content mass ratio [A / B]" shown in Table 3 means "mass of polymer A-1 / mass of polymer B-1 to polymer B-3".

Composition X4 to composition X5 were obtained in the same manner as composition X1 to composition X2, except that polymer B-2 was used instead of polymer B-1.
Without using the polymer B-1 or the polymer B-2, the polymer A-1 was used as it was as the composition X6.
A composition X7 was obtained in the same manner as the composition X3, except that the polymer B-3 was used instead of the polymer B-1.

[Production of expandable substrate film]
<Example 1>
The obtained composition X1 was charged into a hopper of a 25 mmφ single screw extruder (single screw sheet forming machine, manufactured by Tanaka Iron Works Co., Ltd.) equipped with a T die having a lip width of 240 mm. Then, the expandable substrate film (hereinafter also simply referred to as “film”) was obtained by setting the cylinder temperature to 270 ° C. and the die temperature to 270 ° C., extruding the melt-kneaded material from the T-die and cast molding. . Table 3 shows the thickness of the obtained film.

<Example 2 to Example 5, Comparative Example 1 to Comparative Example 2>
A film was obtained in the same manner as in Example 1 except that the composition X2 to the composition X7 were used instead of the composition X1, respectively.

[Evaluation of expandable base film]
The obtained film was subjected to the following measurements and evaluations. The measurement and evaluation methods are shown below. The results are shown in Table 3.

<Measurement of tensile modulus (YM) and tensile elongation at break (EL) of film>
What obtained by cut | disconnecting the obtained film in the dumbbell shape of the "test piece type 5" based on JISK7127 (1999) was used as a test piece.
In accordance with JIS K7127 (1999), using a tensile tester (universal tensile tester 3380, manufactured by Instron), the distance between chucks was 50 mm, the tensile speed was 200 mm / min, and the temperature was 23 ° C. Tensile modulus (YM) (unit: MPa) and tensile elongation at break (EL) (unit:%) were measured.
These measurements were made for each of the MD and TD directions of the film.
Next, a tensile modulus in the MD direction and _{YM MD,} the tensile elongation at break in the TD direction as _{YM TD,} was calculated ratio _[YM MD / _{YM TD].}
Further, the tensile elongation at break in the MD direction and _{EL MD,} the tensile elongation at break in the TD direction as _{EL TD,} was calculated ratio _[EL MD / _{EL TD].}
In addition, about the tensile elasticity modulus (YM), the value which averaged the value of MD direction and the value of TD direction was calculated | required.

<Measurement of Elmendorf tear strength of film>
A film obtained by cutting the obtained film into a 75 mm × 63 mm rectangular shape was used as a test piece.
Based on JIS K7128-2 (1998), the Elmendorf tear strength (unit: N / cm) of the test piece was measured under the condition of a measurement temperature of 23 ° C. using Toyo Seiki Seisakusho SA-WP.
This measurement was performed for each of the MD direction and the TD direction of the film.
Next, the ratio [S _MD / S _TD ] was calculated with the Elmendorf tear strength in the MD direction as S _MD and the Elmendorf tear strength in the TD direction as S _TD .

<Measurement of film expansion rate and necking during expansion>
The obtained film was adhered to an 8-inch ring frame with a rubber roll. Then, a 2 cm square lattice was written on the surface of the film with an oil pen. 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. 1A, the ring frame 44 was fixed to the expander so that the surface of the film 40 was in contact with the stage 42 of the expander. As the expansion machine, Hugle Electronics HS-1800 was used. Then, as shown in FIG. 1B, the stage 42 of the expander was raised 65 mm, and the length in the TD direction and the length in the MD direction of the lattice when the film 40 was expanded were measured. The obtained measured value was applied to the following formula to obtain the expansion rate and the anisotropy of the expansion rate.
Formula: Expansion rate (MD direction, TD direction) (%) = 100 × lattice length after expansion / lattice length before expansion Formula: Anisotropy of expansion rate = expansion rate in MD direction / expansion rate in TD direction

The expansion rate indicates the expansion rate of the expandable substrate film on the stage. As described above, since the stage is raised by 65 mm for all of the expandable base films, the film having a low expansion rate does not expand the film on the stage greatly, and the film outside the stage, that is, the end of the stage. And the film between the ring frame is expanded. Therefore, the extensibility corresponds to the extensibility required in a dicing process of a semiconductor or the like that expands a film and picks up a semiconductor chip corresponding to the lattice.
The ease of necking of the film at the time of expansion is as follows: the film part in contact with the stage (shown on the stage in the table) and the film part in contact with the stage end (shown as the end in the table) Thus, whether or not whitening occurred was visually observed and evaluated as follows.
A: Necking did not occur, and evenly expanded B: Partial whitening was observed, but uniformly expanded C: Necking occurred, resulting in uneven expansion

  When an expandable base film having a uniform expandability in which necking during expansion does not easily occur is used for the expandable adhesive film and the dicing film for semiconductors, the distance between the elements is uniform and the pickup is preferable. Moreover, when an expandable base film is used for a semiconductor dicing film, the pick-up property is improved as the expandable base film is harder to be necked on the stage.

As shown in Table 3, in Examples 1 to 5, it was found that necking during expansion is less likely to occur than in Comparative Examples 1 and 2.
As described above, it was found that necking hardly occurs in the expandable base film containing the composition (X) of the present invention. Moreover, also about the expandable base film containing the thermoplastic elastomer (Y) which satisfy | fills the said conditions in addition to composition (X), and the expandable adhesive film and dicing film which used the expandable base film as a base material layer It is expected that necking is difficult to occur.

Claims (16)

The proportion of the structural unit derived from α-olefin other than 4-methyl-1-pentene having 90 to 100 mol% of the structural unit derived from 4-methyl-1-pentene is 0 mol%. More than 65 mol% and less than 90 mol% of the structural unit derived from 4-methyl-1-pentene and the polymer (A) that is 10 mol% or less and 2 or more carbon atoms other than 4-methyl-1-pentene A copolymer (B) having 10 to 35 mol% of structural units derived from the following α-olefin,
A composition (X) in which the content of the polymer (A) is 50 parts by mass or more and 99 parts by mass or less with respect to 100 parts by mass in total of the polymer (A) and the copolymer (B). Contains an expandable substrate film.   The expandable base film according to claim 1, wherein the polymer (A) has a tensile elastic modulus at 23 ° C measured in accordance with JIS K7127 (1999) of 500 MPa to 2000 MPa.   The expandable base film according to claim 1 or 2, wherein the copolymer (B) contains 70 mol% or more and less than 90 mol% of a structural unit derived from the 4-methyl-1-pentene.   The structural unit derived from the said C2-C20 alpha-olefin which the said copolymer (B) has is a structural unit derived from a propylene, It is any one of Claims 1-3. Expandable base film. Further containing a thermoplastic elastomer (Y),
The content of the thermoplastic elastomer (Y) is 3 parts by mass or more and 50 parts by mass or less with respect to a total of 100 parts by mass of the composition (X) and the thermoplastic elastomer (Y).
The melting point TmY2 derived from the thermoplastic elastomer (Y) measured by a differential scanning calorimeter (DSC) with respect to the expandable substrate film is 200 ° C. or less, or the melting point TmY2 is not substantially observed. 5. The expandable substrate film according to any one of 4 above. Further containing a thermoplastic elastomer (Y),
The content of the thermoplastic elastomer (Y) is 3 parts by mass or more and 50 parts by mass or less with respect to a total of 100 parts by mass of the composition (X) and the thermoplastic elastomer (Y).
The melting point TmY1 measured by a differential scanning calorimeter (DSC) with respect to the thermoplastic elastomer (Y) is 200 ° C. or less, or the melting point TmY1 is not substantially observed. 5. Expandable base film.   The expandable base film according to claim 5 or 6, wherein the thermoplastic elastomer (Y) has a tensile elastic modulus at 23 ° C measured in accordance with JIS K7127 (1999) of 1 MPa to 1500 MPa.   The expandable base film according to any one of claims 5 to 7, wherein the thermoplastic elastomer (Y) comprises an olefin-based elastomer and / or a styrene-based elastomer. The expandable base film according to any one of claims 5 to 8, wherein a density of the thermoplastic elastomer (Y) is 850 kg / m ³ or more and 900 kg / m ³ or less.   The expandable adhesive film containing the base material layer which consists of an expandable base film as described in any one of Claims 1-9, and an adhesive layer.   The expandable adhesive film of Claim 10 which has the said adhesive layer in the outermost surface.   A dicing film comprising the expandable adhesive film according to claim 10.   The proportion of the structural unit derived from α-olefin other than 4-methyl-1-pentene having 90 to 100 mol% of the structural unit derived from 4-methyl-1-pentene is 0 mol%. More than 65 mol% and less than 90 mol% of the structural unit derived from 4-methyl-1-pentene and the polymer (A) that is 10 mol% or less and 2 or more carbon atoms other than 4-methyl-1-pentene A copolymer (B) having 10 to 35 mol% of structural units derived from the following α-olefin, and the content of the polymer (A) is the polymer (A) and the The method includes a step of forming a melt-kneaded product containing the composition (X) that is 50 parts by mass or more and 99 parts by mass or less with respect to 100 parts by mass in total with the copolymer (B). The expandable substrate film according to any one of Film manufacturing method.   The proportion of the structural unit derived from α-olefin other than 4-methyl-1-pentene having 90 to 100 mol% of the structural unit derived from 4-methyl-1-pentene is 0 mol%. More than 65 mol% and less than 90 mol% of the structural unit derived from the polymer (A) and 4-methyl-1-pentene that is 10 mol% or less and 2 or more and 20 or less carbon atoms other than 4-methyl-1-pentene And a copolymer (B) having 10 to 35 mol% of structural units derived from the α-olefin, wherein the content of the polymer (A) is the same as that of the polymer (A) and the copolymer. The melting point TmY1 obtained by a differential scanning calorimeter (DSC) of not less than 50 parts by mass and not more than 99 parts by mass with respect to a total of 100 parts by mass with the coalescence (B) is 200 ° C. or less or the melting point TmY1 Is practically A thermoplastic elastomer (Y) that is not measured, and the content of the thermoplastic elastomer (Y) is 3 parts by mass with respect to a total of 100 parts by mass of the composition (X) and the thermoplastic elastomer (Y). The manufacturing method of the expandable base film as described in any one of Claims 5-9 including the process of shape | molding the melt-kneaded material which is 50 to 50 mass parts. Adhering step of adhering the dicing film according to claim 12 to a semiconductor substrate so that the adhesive layer of the dicing film and the semiconductor substrate are in contact with each other;
A dicing step of dicing the semiconductor substrate to which the dicing film is attached;
An expansion step of expanding the dicing film after the dicing step to obtain a plurality of semiconductor chips separated from each other;
A pickup step of picking up at least one of the plurality of semiconductor chips;
A method for manufacturing a semiconductor device, comprising: The dicing film according to claim 12, wherein the surface of the semiconductor substrate having a circuit surface opposite to the circuit surface is in contact with the adhesive layer of the dicing film and the surface opposite to the circuit surface. A sticking process to stick,
A sealing step for sealing the circuit surface of the semiconductor substrate;
A dicing step of dicing the semiconductor substrate to which the dicing film is attached;
An expansion step of expanding the dicing film after the dicing step to obtain a plurality of semiconductor chips separated from each other;
A pickup step of picking up at least one of the plurality of semiconductor chips;
A method for manufacturing a semiconductor device, comprising: