JP2018076517A - Dicing film, surface protective film for semiconductor, and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expandable substrate film which is excellent in stress relaxation properties and is reduced in anisotropy of tensile elongation at break and anisotropy of tear strength.SOLUTION: The expandable substrate film contains: a polymer A containing 70-95 mol% of a constituent unit (X) derived from 4-methyl-1-pentene and 5-30 mol% of a constituent unit (Y) derived from a C2-20 α-olefin other than 4-methyl-1-pentene; and a polymer B containing the constituent unit (Y) as a main component. When the total amount of the polymer A and the polymer B is 100 pts.mass, the content of the polymer A is 20-90 pts.mass and the content of the polymer B is 10-80 pts.mass.SELECTED DRAWING: None

Description

  The present invention relates to a dicing film, a semiconductor surface protective 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, refer to Patent Documents 1 to 6).
Known materials for the substrate film of the dicing film include polyvinyl chloride (see, for example, Patent Document 7), a mixture of an ethylene / vinyl acetate copolymer and a polyolefin resin (for example, see Patent Document 8), and the like. ing.

  Further, as a method for manufacturing a semiconductor device, a groove having a depth of cut less than the thickness of the semiconductor substrate is formed from the circuit formation surface of the semiconductor substrate on which the circuit is formed. A surface protective sheet (surface protective film for semiconductors) composed of an adhesive layer is attached, and then the back surface (circuit non-formed surface) of the semiconductor substrate is ground to reduce the thickness of the semiconductor substrate and to each individual semiconductor. A method of dividing into chips is also known (see, for example, Patent Document 9).

JP-A-2-215528 JP 2012-188597 A JP 2008-4836 A JP 2009-267389 A JP 2002-343747 A Japanese Patent No. 4945014 Japanese Patent Laid-Open No. 2002-235055 JP 2004-303999 A Japanese Patent No. 3410371

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.
Also in a semiconductor device manufacturing method using a semiconductor surface protective film instead of a dicing film, the semiconductor surface protective film may be expanded after grinding the semiconductor substrate (see, for example, Patent Document 9).
The reason for expanding the dicing film and the semiconductor surface protective film (hereinafter sometimes collectively referred to as “semiconductor film”) is due to the shear stress between the semiconductor chip and the semiconductor film generated during the expansion. This is because the adhesive force between the semiconductor chip and the semiconductor film is reduced, thereby making it easier to pick up the semiconductor chip from the semiconductor film. Another reason for expanding the semiconductor film is to make it easier to pick up the semiconductor chip from the semiconductor film by increasing the interval between the plurality of semiconductor chips.

As described above, the semiconductor film is a film that is expanded after processing the semiconductor substrate (at least one of dicing and grinding, the same shall apply hereinafter).
And in order to improve workability at the time of picking up a semiconductor chip, the base film of the film for semiconductor has a property of uniformly expanding in all directions, that is, isotropic expandability (tensile elongation at break). It is also desirable to have isotropic tear strength.
In other words, in the base film, it is desired to reduce the anisotropy of tensile elongation at break and the anisotropy of tear strength as much as possible.

Further, when the semiconductor substrate is processed, the semiconductor substrate may be warped, cracked, cracked or the like (hereinafter also referred to as “semiconductor substrate warp”). This tendency has become more apparent in recent years as the thickness of semiconductor substrates has become thinner.
In order to suppress warpage of the semiconductor substrate, it is effective to improve the stress relaxation property of the base film of the semiconductor film.

  As described above, for the base film of a semiconductor film, it is desired to improve both the stress relaxation property and reduce the anisotropy of the tensile elongation at break and the anisotropy of the tear strength. In addition, with regard to base films (for example, various protective films) used for purposes other than semiconductor applications, both the improvement of stress relaxation and the reduction of the anisotropy of tensile elongation at break and the anisotropy of tear strength are compatible. You may need to

As a result of studies by the present inventors, the base film is made to contain a polymer containing a structural unit derived from 4-methyl-1-pentene (hereinafter also referred to as “4MP1 polymer”). It was found that the stress relaxation property can be improved.
However, as a result of further studies, it has been found that the base film containing the 4MP1 polymer may have a large anisotropy in tensile elongation at break and anisotropy in tear strength.
Specifically, in a base film containing a 4MP1 polymer, when the difference (absolute value) between the tensile break elongation in the MD direction and the tensile break elongation in the TD direction is large, the tear strength in the MD direction and the TD direction It has been found that the difference (absolute value) from the tear strength of the case may be large.
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 present invention has been made in view of the above circumstances, and provides an expandable base film having excellent stress relaxation properties and reduced anisotropy of tensile elongation at break and anisotropy of tear strength. With the goal.
Moreover, an object of this invention is to provide the dicing film provided with the said expandable base film, and the surface protection film for semiconductors.
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> 70% to 95% by mole of the structural unit (X) derived from 4-methyl-1-pentene and a structure derived from an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene A polymer A containing 5 mol% to 30 mol% of the unit (Y) and a polymer B containing the structural unit (Y) as a main component, and the total of the polymer A and the polymer B When the amount is 100 parts by mass, the content of the polymer A is 20 parts by mass to 90 parts by mass, and the content of the polymer B is 10 parts by mass to 80 parts by mass. the film.
<2> The expandable substrate film according to <1>, wherein the polymer A includes 70 to 90 mol% of the structural unit (X).
<3> The expandable base film according to <1> or <2>, wherein the structural unit (Y) is a structural unit derived from propylene.
<4> The expandable base film according to any one of <1> to <3>, wherein the polymer B includes the structural unit (Y) in an amount of 50 mol% to 100 mol%.
<5> The expandable substrate film according to any one of <1> to <4>, which satisfies the following formula (1) and the following formula (2).
0.5 ≦ EL _MD / EL _TD ≦ 1.5 (1)
Wherein (1), _{EL MD} represents the tensile elongation at break in the MD direction, _{EL TD} indicates a tensile elongation at break in the TD direction. ]
0.4 <= _SMD / _STD <= 1.5 ... Formula (2)
Wherein _{(2), S MD} represents the Elmendorf tear strength in the MD _{direction, S TD} shows Elmendorf tear strength in the TD direction. ]

<6> A dicing film comprising: a base material layer including the expandable base material film according to any one of <1> to <5>, and an adhesive layer.
<7> In accordance with JIS Z0237, the pressure-sensitive adhesive layer is adhered to the surface of a SUS-304-BA plate and left for 60 minutes, and then peeled off from the surface of the SUS-304-BA plate. Dicing film as described in <6> whose adhesive force measured is 0.1N / 25mm-10N / 25mm.
<8> Further, the intermediate layer is disposed between the base material layer and the pressure-sensitive adhesive layer, and has a tensile elastic modulus E (25) at 25 ° C. and a tensile elastic modulus E (60) at 60 ° C. The dicing film according to <6> or <7>, comprising an intermediate layer satisfying the relationship (60) / E (25) <0.1 and having the tensile elastic modulus E (25) of 1 MPa to 10 MPa.

<9> A base material layer including the expandable base film according to any one of <1> to <5>, and an adhesive layer, wherein the non-ground surface of the semiconductor substrate is provided during grinding of the semiconductor substrate. A surface protective film for semiconductors to protect.

<10> An adhering step of adhering the dicing film according to any one of <6> to <8> to a semiconductor substrate so that the semiconductor substrate and the pressure-sensitive adhesive layer face each other, and the dicing. A dicing step of dicing the semiconductor substrate to which the film is attached, an expansion step of obtaining a plurality of semiconductor chips separated from each other by expanding the dicing film after the dicing step, and among the plurality of semiconductor chips And a pickup step of picking up at least one of the semiconductor device.
<11> The semiconductor device according to <10>, wherein the attaching step attaches the dicing film to the semiconductor substrate at a temperature of 40 ° C. to 80 ° C. at a pressure of 0.3 MPa to 0.5 MPa. Production method.
<12> In the attaching step, the dicing film is attached to a circuit forming surface of a semiconductor substrate on which a circuit is formed only on one surface so that the circuit forming surface and the pressure-sensitive adhesive layer face each other. The manufacturing method of a semiconductor device according to <10> or <11>, further comprising a grinding step of grinding a circuit non-formed surface of the semiconductor substrate after the attaching step and before the expanding step. Method.
<13> a groove forming step of forming a groove having a depth of cut less than the thickness of the semiconductor substrate from a circuit forming surface of the semiconductor substrate on which a circuit is formed only on one surface; and the semiconductor substrate on which the groove is formed An adhesion step of adhering the semiconductor surface protection film according to <9> to the circuit formation surface of the substrate so that the circuit formation surface and the pressure-sensitive adhesive layer face each other, and the semiconductor surface protection film A grinding step of grinding a circuit non-formed surface of the semiconductor substrate that is attached; an expansion step of obtaining a plurality of semiconductor chips separated from each other by expanding a dicing film after the grinding step; and the plurality of semiconductors And a pickup step of picking up at least one of the 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 is excellent in stress relaxation property and in which the anisotropy of tensile breaking elongation and the anisotropy of tear strength was reduced can be provided.
Moreover, according to this invention, the dicing film provided with the said expandable base film and the surface protection film for semiconductors 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.

  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 appropriately modified 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 a structural unit (X) derived from 4-methyl-1-pentene of 70 to 95 mol% and a carbon number of 2 to 20 other than 4-methyl-1-pentene. a polymer A containing 5 mol% to 30 mol% of a structural unit (Y) derived from an α-olefin, and a polymer B containing the structural unit (Y) as a main component, and the polymer A When the total amount of the polymer B is 100 parts by mass, the content of the polymer A is 20 parts by mass to 90 parts by mass, and the content of the polymer B is 10 parts by mass to 80 parts by mass. It is. The expandable base film of the present invention may contain other components as necessary.

According to the expandable substrate film of the present invention, an improvement in stress relaxation properties and a reduction in anisotropy in tensile elongation at break and anisotropy in tear strength are compatible.
The reason why such an effect is obtained is presumed as follows.
That is, the expandable substrate film of the present invention contains the polymer A which is a 4MP1 polymer (a polymer containing a structural unit derived from 4-methyl-1-pentene), whereby the stress relaxation property of the film. Is thought to improve.
And as above-mentioned, in the film containing a 4MP1 type polymer, the anisotropy of tensile elongation at break and the anisotropy of tear strength may be large.
With respect to these anisotropies, the expandable substrate film of the present invention contains the polymer A and the polymer B in a predetermined ratio, and the polymer A and the polymer B are a common structural unit. By including the structural unit (Y), the anisotropy of tensile elongation at break and the anisotropy of tear strength are considered to be reduced.
For the above reasons, according to the expandable substrate film of the present invention, it is considered that the stress relaxation property is improved and the anisotropy of the tensile elongation at break and the anisotropy of the tear strength are reduced.

  The expandable base film of the present invention is suitable as a base film for a semiconductor film (dicing film or semiconductor surface protective film). However, the use of the expandable substrate film of the present invention is not limited to the substrate film of a semiconductor film, and it is possible to improve stress relaxation and reduce anisotropy of tensile elongation at break and anisotropy of tear strength. It is also suitable for base films of various films that require both of these.

The structural unit (Y) contained in the polymer A is a structural unit derived from an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene. May be.
Needless to say, however, the polymer B contains as a main component the same structural unit as the structural unit (Y) contained in the polymer A.

In the expandable substrate film of the present invention, as described above, when the total amount of the polymer A and the polymer B is 100 parts by mass, the content of the polymer A is 20 parts by mass to 90 parts by mass. The content of the polymer B is 10 parts by mass to 80 parts by mass.
When the content of the polymer A is 20 parts by mass or more, the stress relaxation property is improved.
When the content of the polymer A is 90 parts by mass or less, the anisotropy of the tensile elongation at break and the anisotropy of the tear strength can be reduced (for example, a value in the MD direction and a value in the TD direction). The difference (absolute value) is smaller.
The content of the polymer A is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, further preferably 40 parts by mass or more, further preferably 50 parts by mass or more, from the viewpoint of further improving stress relaxation properties. 60 parts by mass or more is particularly preferable.
Further, the content of the polymer A is preferably 80 parts by mass or less, and more preferably 75 parts by mass or less from the viewpoint of further reducing the anisotropy of tensile elongation at break and the anisotropy of tear strength.

Moreover, in the manufacturing method of the semiconductor device using the semiconductor film (dicing film or semiconductor surface protective film), in order to suppress the warp of the semiconductor substrate, the stress relaxation of the base film of the semiconductor film described above is performed. In addition to the method of improving the property, a method of allowing the base film to contain a flexible component (for example, the polymer B) is also conceivable.
However, when there is too much content of the flexible component in the said base film, there exists a tendency for the heat resistance of a film to fall.
In this regard, the expandable substrate film of the present invention is excellent in heat resistance by containing 20 parts by mass or more of the polymer A described above as a 4MP1 polymer.
Thus, since the expandable base film of the present invention is a film that can suppress warpage of the semiconductor substrate while maintaining excellent heat resistance, not only as a base film of a dicing film, It is also suitable as a base film for a semiconductor surface protection film for protecting a circuit formation surface of a semiconductor substrate when grinding a circuit non-formation surface of a semiconductor substrate having a circuit formed only on the surface.
Furthermore, by using the expandable base film of the present invention, only one kind of film (expandable base film of the present invention) is attached to the semiconductor substrate, and then both dicing and grinding are performed (whichever comes first). It is also possible to manufacture a semiconductor device in the form of In the manufacturing method of this form, the expandable base film of the present invention has both a role as a dicing film and a role as a surface protective film for a semiconductor that protects a circuit forming surface of a semiconductor substrate during grinding. .

Moreover, the expansible base film of this invention is excellent in impact resistance by containing the polymer B. FIG.
That is, according to the expandable substrate film of the present invention, both excellent stress relaxation properties and excellent impact resistance are achieved.

As described above, the expandable substrate film of the present invention has reduced anisotropy in tensile elongation at break. Regarding the anisotropy of tensile elongation at break, the expandable substrate film of the present invention preferably satisfies the following formula (1).
0.5 ≦ EL _MD / EL _TD ≦ 1.5 (1)
Wherein (1), _{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, the expandable base film of the present invention has reduced tear strength anisotropy as described above. Regarding the anisotropy of tear strength, the expandable substrate film of the present invention preferably satisfies the following formula (2).
0.4 <= _SMD / _STD <= 1.5 ... Formula (2)
Wherein _{(2), S MD} represents the Elmendorf tear strength in the MD _{direction, S TD} shows Elmendorf tear strength in the TD direction. ]

  In the present invention, Elmendorf tear strength refers to a value measured in accordance with JIS K7128-2 (1998) under the condition of a measurement temperature of 23 ° C.

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 .

  It is particularly preferable that the expandable base film of the present invention satisfies both the above formula (1) and the above formula (2).

Moreover, it is also preferable that the expandable base film of the present invention has reduced anisotropy in tensile elastic modulus. More preferably, it is satisfy | filling following formula (3).
0.5 ≦ YM _MD / YM _TD ≦ 1.5 (3)
[In Formula (2), YM _MD shows the tensile elasticity modulus of MD direction, and YM _TD shows the tensile elasticity modulus of TD direction. ]

  In the present invention, the tensile elastic modulus refers to a value measured according to JIS K7127 (1999) under the condition of a measurement temperature of 23 ° C.

The lower limit of YM _MD / YM _TD is preferably 0.7, and more preferably 0.8.
The upper limit of YM _MD / YM _TD is preferably 1.3, and more preferably 1.2.
YM _MD is preferably 300 MPa to 2000 MPa, and more preferably 500 MPa to 1500 MPa.
If the YM _MD is 300 MPa or more, the strength of the expandable film is further improved.
If the YM _MD is 2000 MPa or less, the expandable film can be more easily expanded.
The preferable range of YM _{TD is the same as} the preferable range of YM _MD .

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

[Polymer A]
The polymer A is derived from 70 mol% to 95 mol% of the structural unit (X) derived from 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene. The structural unit (Y) is contained in an amount of 5 mol% to 30 mol%.

The content of the structural unit (X) in the polymer A is 70 mol% to 95 mol%, preferably 70 mol% to 90 mol%, more preferably 75 mol% to 90 mol%, and more preferably 80 mol% to 90 mol%. Mole% is particularly preferred.
When the content of the structural unit (X) in the polymer A is 70 mol% or more, the stress relaxation property is improved.
When the content of the structural unit (X) in the polymer A is 95 mol% or less, the anisotropy of tensile elongation at break and the anisotropy of tear strength are reduced.

The content of the structural unit (Y) in the polymer A (when the structural unit (Y) is 2 or more, the total content of the 2 or more) is 5 mol% to 30 mol%, and 10 mol. % To 30 mol% is preferable, 10 mol% to 25 mol% is more preferable, and 10 mol% to 20 mol% is particularly preferable.
When the content of the structural unit (Y) in the polymer A is 5 mol% or more, the anisotropy of tensile elongation at break and the anisotropy of tear strength are reduced.
When the content of the structural unit (Y) in the polymer A is 30 mol% or less, the stress relaxation property is improved.

As a C2-C20 alpha-olefin other than 4-methyl-1-pentene which forms a structural unit (Y), the viewpoint which reduces the anisotropy of tensile elongation at break and the anisotropy of tear strength more To ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-hexadecene and 1-octadecene, and propylene, 1-octene, 1-decene, 1-hexadecene and 1-octadecene are preferable. More preferred are ethylene, propylene and butene, and particularly preferred is propylene.
Moreover, the impact resistance of an expandable base film also improves that the said alpha olefin is the said preferable range.

The polymer A is a constitutional unit derived from 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 unit 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 polymer A contains the other structural units, only one kind of the other structural units may be contained, or two or more kinds may be contained.

  The content rate (mol%) of each structural unit in the polymer A can be measured by the following method.

~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

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, and 0.5 dl / g to 4.0 dl / g. It is more preferable that When the intrinsic viscosity [η] of the polymer A is within the above range, the number of low molecular weight substances is small, so that 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.
About 20 mg of the polymer A is dissolved in 25 ml of decalin, and then 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 1).
[Η] = lim (ηsp / C) (C → 0) Equation 1

The weight average molecular weight of the polymer A (Mw), from the viewpoint of film formability, 1 × is preferably ¹⁰ 4 ^~2 × ^{10 6,} more that is located at 1 × ¹⁰ 4 ~1 × ^{10 6} preferable.
Moreover, the molecular weight distribution (Mw / Mn) of the polymer A is preferably 1.0 to 3.5, more preferably 1.1 to 3.0, from the viewpoints of film stickiness and appearance.

  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 (GPC). ) Is a value calculated by a standard polystyrene conversion method.

~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 melt flow rate (MFR) of the polymer A is preferably 0.1 g / 10 min to 100 g / 10 min from the viewpoint of fluidity at the time of molding, and 0.5 g / 10 min to 50 g / 10 min. More preferably, it is more preferably 0.5 g / 10 min to 30 g / 10 min.
The melt flow rate (MFR) of the polymer A is a value measured at 230 ° C. under a load of 2.16 kg in accordance with ASTM D1238.

The density of the polymer A, 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 polymer A is a value measured according to JIS K7112 (density gradient tube method).

The melting point (Tm) of the polymer A is not observed or is preferably 100 ° C to 180 ° C, more preferably not observed, or more preferably 110 ° C to 160 ° C.
The melting point (Tm) of the polymer A is a value measured by the following method using a differential scanning calorimetry (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, it 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.

The polymer A 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 in the temperature range of −5 ° C. to 50 ° C., preferably 0 ° C. to 45 ° C., more preferably within a temperature range of 0 ° C. to 40 ° C., and the maximum loss tangent (tan δ) is preferably 0.4 or more, more preferably 0.5 or more, 1.0 or more is more preferable, and 1.2 or more is particularly preferable. When the maximum value of the loss tangent (tan δ) is within the above temperature range and the maximum value is 0.4 or more, the polymer A is more excellent in stress relaxation properties.
The maximum value of the loss tangent (tan δ) of the polymer A and the temperature at which the maximum value is shown were measured using a viscoelasticity measuring apparatus (MCR301, manufactured by Anton Paar) at a frequency of 10 rad / It is a value obtained by measuring dynamic viscoelasticity in a temperature range of −70 ° C. to 180 ° C. with s.

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

  The content of the polymer A in the expandable substrate film of the present invention is as described above.

[Polymer B]
The polymer B has the structural unit (Y) as a main component.
That is, the polymer B contains as a main component the same structural unit as the structural unit (Y) contained in the polymer A.
The preferable range of the C 2-20 α-olefin other than 4-methyl-1-pentene, which forms the structural unit (Y), is as described above.

  The content of the structural unit (Y) in the polymer B is preferably 50 mol% to 100 mol%, more preferably 70 mol% to 100 mol%, still more preferably 80 mol% to 100 mol%, and 90 mol%. ˜100 mol% is particularly preferred.

The melt flow rate (MFR) of the polymer B is preferably 0.1 g / 10 min to 100 g / 10 min, and preferably 0.5 g / 10 min to 50 g / 10 min from the viewpoint of film moldability and mechanical properties of the film. It is more preferable.
The melt flow rate (MFR) of the polymer B is a value measured at 230 ° C. under a load of 2.16 kg in accordance with ASTM D1238.

The density of the polymer B, light weight, and from the viewpoint of dispersion property when the polymer was a composition of ^A, is preferably ^{820kg / m 3 ~960kg / m 3} , 830kg / m 3 ~940kg / more preferably m ^3.
The density of the polymer B is a value measured according to JIS K7112 (density gradient tube method).

  The content of the polymer B in the expandable substrate film of the present invention is as described above.

[Other ingredients]
The expandable substrate film of the present invention may contain other components other than the polymer A and the polymer B as necessary.
However, the total amount of the polymer A and the polymer B is preferably 80% by mass or more, more preferably 90% 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. Is more preferable, and 100% by mass (that is, the expandable base film is composed of the polymer A and the polymer B) is most preferable.

[Structure of expandable base film]
The expandable base film of the present invention preferably has a structure (phase dispersion structure) in which polymer A and polymer B having relatively high crystallinity are phase-separated and dispersed. Specifically, the expandable substrate film of the present invention preferably has a sea-island structure. The sea-island structure referred to in the present invention refers to a structure in which the polymer A and the polymer B have a phase separation structure, the major component is a sea component, and the minor component is an island component.

  If the expandable substrate film of the present invention has a sea-island structure, it can have more excellent stress relaxation properties and impact resistance.

  In addition, it can confirm that the expandable base film of this invention has a sea island structure with a transmission electron microscope (TEM: Transmission Electron Microscope), for example. Specifically, the expandable substrate film is ground to produce an ultrathin section, and only one of the components is selectively stained with a heavy metal such as ruthenium tetroxide or osmium tetroxide, and then a transmission electron microscope. Observe with.

  The expandable base film having a sea-island structure composed of the polymer A and the polymer B is obtained, for example, by mixing the polymer A and the polymer B by dry blending and forming a film by extrusion.

[Method for producing expandable substrate film]
An example of the manufacturing method of the expandable base film of this invention is demonstrated. The expandable substrate film of the present invention can be produced, for example, by the following method. However, the present invention is not limited to this.
The polymer A and the polymer B are mixed (for example, dry blended). Subsequently, the obtained mixture is put into a hopper of an extruder provided with a T die, and the cylinder temperature is set to 100 ° C. to 270 ° C. and the die temperature is set to 200 ° C. to 270 ° C. The melt-kneaded material is extruded from a T die and cast to obtain an expandable substrate 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.

[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.
Further, as described above, the expandable base film of the present invention is also suitable as a base film for a semiconductor surface protective film that is adhered to a semiconductor substrate before grinding the semiconductor substrate in the method for manufacturing a semiconductor device. It is.
Moreover, the expandable base film of the present invention is also suitable as a protective film other than the dicing film and the semiconductor surface protective film.
As other protective films, for example, various plastic products such as building materials and optical parts, metal products, glass products, etc. are applied to these surfaces for the purpose of preventing scratches and dust during transport, storage and processing. A protective film to be worn is mentioned.

[Dicing film]
The dicing film of this invention is equipped with the base material layer containing the expandable base film of this invention mentioned above, and an adhesive layer.

[Base material layer]
A base material layer may consist only of the expandable base film of this invention, and the laminated body provided with the expandable base film of this invention and another base film may be sufficient as it.
When the base material layer is the above laminate, the other base material film is preferably a film made of a polymer having good affinity with the polymer A and the polymer B. For example, polyethylene, ethylene-acetic acid A film made of vinyl copolymer, polypropylene, polyethylene terephthalate or the like is preferable. Moreover, as another base film, the intermediate layer mentioned later is also preferable.
Moreover, when a base material layer is the said laminated body, the contact bonding layer may interpose between the expandable base film of this invention, and another base film.

Although there is no restriction | limiting in particular in the elasticity modulus of a base material layer, The storage elastic modulus G '(25) in 25 degreeC measured at the frequency of 1.6 Hz of a base material layer is 5 * 10 < ⁷ > Pa or more. Is preferably 1 × 10 ⁸ Pa to 2 × 10 ¹⁰ Pa. When the storage elastic modulus G ′ (25) of the base material layer is 5 × 10 ⁷ Pa or more, warping of the semiconductor substrate can be more effectively suppressed during or after dicing of the semiconductor substrate.

The thickness of the base material layer is preferably 20 μm to 500 μm, more preferably 20 μm to 350 μm, and particularly preferably 50 μm to 300 μm.
When the thickness of the base material layer is within the above range, warpage of the semiconductor substrate can be more effectively suppressed, and the handling property of the dicing film is also good.

  Further, when the substrate layer is the above laminate, the ratio of the thickness of the expandable substrate film of the present invention to another substrate film [thickness of the expandable substrate film of the present invention / other substrate The thickness of the film] is not particularly limited, but is preferably 100/5 to 100/100, more preferably 100/10 to 100/80, still more preferably 100/10 to 100/60, and 100/10 to 100 / 50 is particularly preferred.

(Adhesive layer)
The pressure-sensitive adhesive layer is a layer for adhering the dicing film to the semiconductor substrate.
The pressure-sensitive adhesive layer is preferably the outermost surface layer in the dicing film. However, the dicing film of the present invention may include a release film (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 having a release film, the release film is removed before the dicing film is attached to the semiconductor substrate, and the exposed adhesive layer and the semiconductor substrate are in contact with each other so that the release film is removed. Is preferably attached to a semiconductor substrate.

The pressure-sensitive adhesive layer is measured according to JIS Z0237 when it is attached to the surface of a SUS-304-BA plate and left for 60 minutes and then peeled off from the surface of the SUS-304-BA plate. The adhesive strength is preferably 0.1 N / 25 mm to 10 N / 25 mm.
If the adhesive strength is 0.1 N / 25 mm or more, the dicing film can be effectively attached to the semiconductor substrate.
When the dicing film is peeled off from the semiconductor substrate when the adhesive strength is 10 N / 25 mm or less, damage to the semiconductor substrate can be further suppressed, and after the dicing film is peeled off from the semiconductor substrate, the adhesive to the semiconductor substrate The remaining layer can be further suppressed.
The adhesive strength is preferably 0.1 N / 25 mm to 5 N / 25 mm, and more preferably 0.1 N / 25 mm to 3 N / 25 mm.
If the pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer has an adhesive force switching function such as a radiation curable type, a thermosetting type, or a heating foam type, which will be described later, the adhesive force is switched by radiation irradiation or the like to decrease. It is preferable that the adhesive strength after being in the above range.

  The pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include natural rubber-based; synthetic rubber-based; silicone rubber-based; acrylic pressure-sensitive adhesives such as acrylic acid alkyl esters and methacrylic acid alkyl esters. . Among these, acrylic pressure-sensitive adhesives are preferable from the viewpoint of tackiness and the like.

The pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer is a pressure-sensitive adhesive that has a pressure-sensitive adhesive switching function that reduces the pressure-sensitive adhesive force depending on certain conditions such as radiation-curing type, heat-curing type, and heat-foaming type, or a pressure-sensitive adhesive that does not have the switching function. Any of the agents may be used.
In the dicing film of the present invention, the adhesive is preferably an acrylic ultraviolet curable adhesive having an adhesive force switching function from the viewpoint that it can be easily peeled from the semiconductor substrate and there is little risk of damaging the semiconductor substrate. .

  Examples of the acrylic UV curable pressure-sensitive adhesive include 100 parts by mass of an acrylic ester copolymer in which a photopolymerizable carbon-carbon double bond is introduced in the molecule, and a photopolymerizable carbon-carbon in the molecule. Examples thereof include an adhesive containing 0.1 to 20 parts by mass of a low molecular weight compound having two or more double bonds and 5 to 15 parts by mass of a photoinitiator.

  Examples of the acrylic ester copolymer contained in the acrylic UV curable pressure-sensitive adhesive include a copolymer obtained by copolymerizing a monomer having an ethylenic double bond and a copolymerizable monomer having a reactive functional group. Examples thereof include compounds obtained by reacting a combination with a monomer containing a photopolymerizable carbon-carbon double bond having a group capable of reacting with the reactive functional group.

  Examples of the monomer having an ethylenic double bond contained in the copolymer for obtaining an acrylic ester copolymer include, for example, methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate, ethyl acrylate, etc. Acrylic acid alkyl ester and methacrylic acid alkyl ester monomers; vinyl esters such as vinyl acetate; monomers having an ethylenic double bond such as acrylonitrile; acrylamide; styrene;

  Examples of the copolymerizable monomer having a reactive functional group contained in the copolymer for obtaining an acrylic ester copolymer include (meth) acrylic acid, maleic acid, 2-hydroxyethyl (meta ) Acrylate, glycidyl (meth) acrylate, N-methylol (meth) acrylamide and the like. Only one of these may be polymerized with the monomer having an ethylenic double bond, or two or more may be polymerized.

  In the case of obtaining an acrylic ester copolymer, the polymerization ratio of the monomer having an ethylenic double bond and the copolymerizable monomer having a reactive functional group is 70 mass% to 99 mass%: 30 mass% to 30 mass%. It is preferably 1% by mass, more preferably 80% by mass to 95% by mass: 20% by mass to 5% by mass.

  In addition, the monomer containing a photopolymerizable carbon-carbon double bond for obtaining an acrylate ester copolymer is not particularly limited, and a reactive functional group (for example, carboxyl group) contained in the copolymer is not limited. A photoreactive monomer including a photopolymerizable carbon-carbon double bond having a group capable of reacting with a group, a hydroxyl group, a glycidyl group, and the like.

  Examples of combinations of the reactive functional group contained in the copolymer and the group capable of reacting with the reactive functional group of the photoreactive monomer include a carboxyl group and an epoxy group, a carboxyl group and an aziridyl group, and a hydroxyl group and an isocyanate. Groups and the like. Among such combinations, a combination that easily causes an addition reaction is desirable. In addition, the group capable of reacting with the reactive functional group of the photoreactive monomer is not limited to a group that undergoes an addition reaction with the reactive functional group of the copolymer, and is a group that undergoes a condensation reaction with the reactive functional group of the copolymer. There may be.

  Examples of the low molecular weight compound having two or more photopolymerizable carbon-carbon double bonds in the molecule contained in the acrylic UV-curable pressure-sensitive adhesive include tripropylene glycol di (meth) acrylate and trimethylolpropane tri (Meth) acrylate, tetramethylolmethane tetraacrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like. Only one type of low molecular weight compound may be contained in the acrylic ultraviolet curable pressure-sensitive adhesive, or two or more types may be contained. The “low molecular weight compound” as used herein refers to a compound having a molecular weight of 10,000 or less, and the molecular weight of the low molecular weight compound is more preferably 5,000 or less.

  Examples of the photoinitiator contained in the acrylic ultraviolet curable adhesive include, for example, benzoin, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michler ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, acetophenone diethyl ketal, benzyl Examples include dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one. As for a photoinitiator, only 1 type may be contained in the ultraviolet curing adhesive, and 2 or more types may be contained. The content of the photoinitiator in the ultraviolet curable adhesive is preferably 5 parts by mass to 15 parts by mass with respect to 100 parts by mass of the acrylic ester copolymer, and is 5 parts by mass to 10 parts by mass. More preferably.

  The acrylic ultraviolet curable pressure-sensitive adhesive may contain a crosslinking agent. Examples of the cross-linking agent include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether; tetramethylolmethane-tri-β-aziridinyl propionate, Trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N, N′-hexamethylene-1,6-bis ( Aziridine compounds such as 1-aziridinecarboxamide); isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, and polyisocyanate.

  The acrylic ultraviolet curable pressure-sensitive adhesive may contain rosin-based and terpene resin-based tackifiers, various surfactants, and the like. According to these, it is possible to adjust the adhesive properties of the acrylic ultraviolet curable adhesive.

  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.

[Middle layer]
The dicing film of the present invention may include an intermediate layer between the base material layer and the pressure-sensitive adhesive layer.
As the intermediate layer, the tensile elastic modulus E (25) at 25 ° C. and the tensile elastic modulus E (60) at 60 ° C. satisfy the relationship of E (60) / E (25) <0.1, and the E (25 ) Is preferably 1 to 10 MPa (hereinafter also referred to as “specific intermediate layer”).
Even if the dicing film of the present invention includes the specific intermediate layer, unevenness (for example, unevenness due to electrodes, bumps, solder balls, etc.) exists on the surface of the semiconductor substrate to which the dicing film is attached. The specific intermediate layer can follow the unevenness and absorb the unevenness. Thereby, the adhesiveness of a dicing film and the surface (uneven surface) of a semiconductor substrate can be improved more.

The E (25) is preferably 1 MPa to 10 MPa, more preferably 2 MPa to 9 MPa. If E (25) is in the above range, the shape at room temperature after the sheet is attached can be maintained, and the adhesion during processing can be maintained.
The E (60) is preferably 0.005 MPa to 1.0 MPa, and more preferably 0.01 MPa to 0.5 MPa. If E (60) is in the above range, fluidity is exhibited when the sheet is attached under heating, so that good followability to unevenness can be obtained.

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

The density of the intermediate layer is ^{preferably 800kg / m 3 ~890kg / m 3} , more preferably ^{830kg / m 3 ~890kg / m 3} , more preferably ^{850kg / m 3 ~890kg / m 3} . When the density of the intermediate layer is 800 kg / m ³ or more, the elastic modulus can be further improved and the shape fixing force can be further improved. When the density is 890 kg / m ³ or less, it is possible to suppress the elastic modulus from becoming too high, and therefore followability to unevenness is further improved.

The intermediate layer preferably contains a polymer.
The polymer that can be contained in the intermediate layer is preferably an olefin copolymer. The olefin copolymer is preferably an α-olefin copolymer having an α-olefin having 2 to 12 carbon atoms as a main structural unit.

  Examples of the α-olefin having 2 to 12 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, and 3-methyl. -1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene and the like are included.

  Among them, the ternary copolymer of ethylene / propylene copolymer, ethylene / 1-butene copolymer, and ethylene / propylene / α-olefin having 4 to 12 carbon atoms is excellent in terms of excellent conformability at the time of pasting. And ethylene / α-olefin copolymers such as polymers; and propylene / 1-butene copolymers / α-olefin terpolymers having 5 to 12 carbon atoms are preferred, and ethylene / propylene copolymers are preferred. More preferred. This is because propylene has high heat-meltability among olefin copolymers. Commercially available α-olefin copolymers include TAFMER (registered trademark) and NOTIO (registered trademark) manufactured by Mitsui Chemicals.

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

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

  The thickness of the intermediate layer is preferably larger than the step provided on one surface of the semiconductor substrate to which the dicing film is bonded, and this step (for example, unevenness (including solder bumps) on the circuit forming surface of the semiconductor substrate) is embedded. The thickness is not particularly limited as long as the thickness can be adjusted. For example, if the uneven step is about 100 μm, the thickness of the intermediate layer can be 100 to 300 μm. That is, the thickness of the intermediate layer is preferably 1 to 3 times, more preferably 1 to 2 times the step of the semiconductor substrate.

The dicing film may be provided with other layers other than the above.
As other layers, for example, known layers described in Japanese Patent No. 4945014 can be used.
Examples of the other layer include a low friction layer (see, for example, paragraphs 0075 to 0076 of Japanese Patent No. 494014) provided on the side opposite to the side where the pressure-sensitive adhesive layer is present when viewed from the base material layer.

[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.

Moreover, when the base material layer in the dicing film of the present invention is a laminate of the expandable base film of the present invention and another base film, the method for forming the base material layer that is a laminate is also particularly limited. There is no.
As a method of forming a base material layer that is a laminate, for example, a polymer that forms the expandable base film of the present invention and a polymer that forms another base film are coextruded using a multilayer film forming machine or the like. Forming the laminate; after forming the expandable substrate film of the present invention and another substrate film by a known method such as a calendering method, a T-die extrusion method, an inflation method, or a casting method, respectively. A method of forming a laminate by laminating the substrate by dry lamination or the like; either one of the expandable substrate film of the present invention and the other substrate film is calendered, T-die extruded, inflation, cast A method of forming a laminate by forming the film by a known method such as the above, and forming the other on the formed film by extrusion coating; And the like.
In the method using the dry laminate or the like, an adhesive layer may be interposed between the expandable substrate film of the present invention and another substrate film, and the expandable substrate film of the present invention and other substrates are also included. Each film may be subjected to easy adhesion treatment such as corona discharge treatment.

  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.

[Surface protective film for semiconductors]
The surface protective film for a semiconductor of the present invention comprises a base material layer containing the expandable base film of the present invention described above and an adhesive layer, and protects the non-ground surface of the semiconductor substrate during grinding of the semiconductor substrate. It is.
The preferable form and the preferable manufacturing method of the surface protection film for semiconductors of this invention are the same as the preferable form and the preferable manufacturing method of the dicing film of this invention mentioned above.
In addition, as above-mentioned, the dicing film of this invention may have the function of the surface protection film for semiconductors of this invention which protects the non-ground surface of a semiconductor substrate at the time of grinding of a semiconductor substrate.

[Method for Manufacturing Semiconductor Device]
[First Embodiment]
In a first embodiment of a semiconductor device manufacturing method of the present invention (hereinafter also referred to as “first manufacturing method”), the dicing film of the present invention described above is applied to a semiconductor substrate, the surface of the semiconductor substrate, and the adhesive. Each was separated by expanding the dicing film after the dicing step, the dicing step for dicing the semiconductor substrate on which the dicing film was adhered, and the adhering step for adhering the layers so as to face each other An expansion step of obtaining a plurality of semiconductor chips, and a pickup step of picking up at least one of the plurality of semiconductor chips. The first manufacturing method may have other steps.

In the first production method, the dicing film of the present invention provided with the expandable substrate film of the present invention having excellent stress relaxation properties is used. For this reason, the curvature etc. of the semiconductor substrate after a sticking process are suppressed.
In the first production method, the dicing film of the present invention in which the anisotropy of tensile elongation at break and the anisotropy of tear strength is reduced is used. For this reason, when expanding a dicing film in an expansion process, a dicing film can be expanded isotropically, suppressing a fracture and a tear of a dicing film. 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. The workability when doing so 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.

  Hereinafter, each process of the first manufacturing method will be described.

<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 face 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 (especially, paragraphs 0072 to 0076 and FIGS. 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 effect of the first manufacturing method described above is 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.

<Grinding process>
The first manufacturing method may further include a grinding step of grinding the semiconductor substrate after the attaching step and before the expanding step.
When the first manufacturing method includes a grinding step, the adhering step includes the dicing film, the circuit forming surface, and the pressure-sensitive adhesive layer on a circuit forming surface of a semiconductor substrate on which a circuit is formed only on one surface. And the grinding step is preferably a step of grinding a circuit non-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.

<Other processes>
The 1st manufacturing method may have other processes other than the above.
As other steps, known steps can be used in the method of manufacturing a semiconductor device.
As other steps, for example, a step of performing electrode formation (bonding) and resin sealing (baking) on the circuit formation surface of the semiconductor substrate by a commonly used method after the pasting step and before the dicing step. . 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 as described above, it can be suitably used for WLP (Wafer Level Package). Regarding WLP (Wafer Level Package), for example, descriptions in Japanese Patent Application Laid-Open Nos. 2008-16539 and 2012-188597 can be referred to as appropriate.

[Second Embodiment]
According to a second embodiment of the method for manufacturing a semiconductor device of the present invention (hereinafter also referred to as “second manufacturing method”), the thickness of the semiconductor substrate is measured from the circuit formation surface of the semiconductor substrate in which the circuit is formed only on one surface. A groove forming step of forming a groove having a depth of cut of less than the thickness; and the circuit forming surface of the semiconductor substrate on which the groove is formed, the surface protective film for semiconductor of the present invention described above, the circuit forming surface and the adhesive A bonding step of bonding so as to face the agent layer, a grinding step of grinding a circuit non-formed surface of the semiconductor substrate on which the semiconductor surface protective film is bonded, and a semiconductor surface after the grinding step The method includes an expansion step of obtaining a plurality of semiconductor chips separated from each other by expanding the protective film, and a pickup step of picking up at least one of the plurality of semiconductor chips. The second manufacturing method may have other steps.

The groove forming step in the second manufacturing method corresponds to the dicing step in the first manufacturing method.
However, the groove forming step in the second manufacturing method is provided before the attaching step, is limited to forming the groove from the circuit forming surface of the semiconductor substrate, and the groove to be formed Is different from the dicing step in the first manufacturing method in that the depth of cut is limited to less than the thickness of the semiconductor substrate (that is, the dicing is limited to the above-described half-cut dicing).
The groove forming step in the second manufacturing method is the same as the dicing step in the first manufacturing method in the points other than the above, and the preferred embodiment is also the same.

Moreover, the sticking process in a 2nd manufacturing method respond | corresponds to the sticking process in a 1st manufacturing method.
However, the sticking process in the second manufacturing method is a sticking process in the first manufacturing method in that it is provided after the groove forming process and the dicing film is changed to a surface protective film for semiconductors. Different from the landing process.
The sticking process in the second manufacturing method is the same as the sticking process in the first manufacturing method in points other than the above, and the preferred form is also the same.

The second manufacturing method is different from the first manufacturing method in that a grinding step is essential.
In the grinding step in the second manufacturing method, the semiconductor substrate is preferably ground until the bottom of the groove formed in the groove forming step is reached. Thereby, a semiconductor substrate is parted and a semiconductor chip is obtained.
The preferable range of the grinding process in the second manufacturing method is the same as the preferable range of the grinding process that may be provided in the first manufacturing method.

The expansion process and the pick-up process in the second manufacturing method are the same as the expansion process and the pick-up process in the first manufacturing method, respectively, and the preferred embodiments are also the same.
In addition, other steps that may be provided in the second manufacturing method are the same as other steps in the first manufacturing method.

The second manufacturing method is common to the first manufacturing method in that a semiconductor film (in the second manufacturing method, a semiconductor surface protective film) is expanded to obtain a plurality of semiconductor chips that are separated from each other. doing.
And the surface protection film for semiconductors is equipped with the expandable base film of this invention similarly to the dicing film.
For this reason, the same effect as the first manufacturing method can be obtained also by the second manufacturing method.

  Regarding the second production method, the description of paragraphs 0030 to 0032 and FIGS. 1 to 4 of Japanese Patent No. 3410371 are appropriately referred to, except that the semiconductor surface protective film of the present invention is used as the surface protective sheet. be able to.

  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.

[Synthesis Example 1] Synthesis of Polymer A-1 (Polymer A) Into a SUS autoclave with a 1.5-liter stirring blade sufficiently purged with nitrogen, 300 ml of n-hexane (on a dry nitrogen atmosphere, on activated alumina) ), And 450 ml of 4-methyl-1-pentene were charged at 23 ° C., and then 0.75 ml of a 1.0 mmol / ml toluene solution of triisobutylaluminum (TIBAL) was charged. did.
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 A-1 as the polymer A.

Table 1 shows the measurement results of various physical properties of the obtained polymer A-1.
The content of 4-methyl-1-pentene in the polymer A-1 was 84.1 mol%, and the content of propylene was 15.9 mol%. Further, the density of the polymer A-1 was 838 kg / m ³ . Polymer A-1 had an intrinsic viscosity [η] of 1.5 dl / g, a weight average molecular weight (Mw) of 340,000, and a molecular weight distribution (Mw / Mn) of 2.1. The melting point (Tm) of the polymer A-1 was 132 ° C., and the maximum value of tan δ was 1.6 (temperature when showing the maximum value: 39 ° C.).

[Synthesis Example 2] Synthesis of Polymer A-2 (Polymer A) Into a SUS autoclave with a 1.5 L stirring blade sufficiently purged with nitrogen, 300 ml of n-hexane (on a dry nitrogen atmosphere, on activated alumina) ), And 450 ml of 4-methyl-1-pentene were charged at 23 ° C., and then 0.75 ml of a 1.0 mmol / ml toluene solution of triisobutylaluminum (TIBAL) was charged. did.
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 A-2 as the polymer A.

Table 1 shows the measurement results of various physical properties of the obtained polymer A-2.
The content of 4-methyl-1-pentene in the polymer A-2 was 72.5 mol%, and the content of propylene was 27.5 mol%. Further, the density of the polymer A-2 was 839 kg / m ³ . Polymer A-2 had an intrinsic viscosity [η] of 1.5 dl / g, a weight average molecular weight (Mw) of 337,000, and a molecular weight distribution (Mw / Mn) of 2.1. The melting point (Tm) of the polymer A-2 was not observed, and the maximum value of tan δ was 2.8 (temperature when showing the maximum value: 31 ° C.).

[Synthesis Example 3] Synthesis of Polymer A-3 (Polymer A) A SUS autoclave with a 1.5-liter stirring blade sufficiently purged with nitrogen was charged with 750 ml of 4-methyl-1-pentene at 23 ° C. Then, 0.75 ml of a 1.0 mmol / ml toluene solution of triisobutylaluminum (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 at 130 ° C. under reduced pressure for 12 hours to obtain 45.9 g of a powdery polymer A-3 as the polymer A.

Table 1 shows the measurement results of various physical properties of the resulting polymer A-3.
The content of 4-methyl-1-pentene in the polymer A-3 was 92.3 mol%, and the content of propylene was 7.7 mol%. Further, the density of the polymer A-3 was 832 kg / m ³ . Polymer A-3 had an intrinsic viscosity [η] of 1.6 dl / g, a weight average molecular weight (Mw) of 370,000, and a molecular weight distribution (Mw / Mn) of 2.1. The melting point (Tm) of the polymer A-3 was 178 ° C., and the maximum value of tan δ was 0.4 (temperature when showing the maximum value: 40 ° C.).

A method for measuring various physical properties of the polymer is shown below.
The measurement results are shown in Table 1 below.

〔composition〕
In the polymer A, the structural unit (X) (the structural unit derived from 4-methyl-1-pentene) and the structural unit (Y) (the structural unit derived from propylene; The content (mol%) of (denoted) was measured by ¹³ C-NMR. The measurement conditions are as follows.

~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

[Intrinsic viscosity [η]]
The intrinsic viscosity [η] of the polymer A was measured at 135 ° C. in a decalin solvent using an Ubbelohde viscometer as a measuring device.
Specifically, about 20 mg of the powdery polymer A was dissolved in 25 ml of decalin, and then the specific viscosity ηsp was measured in an oil bath at 135 ° C. using an Ubbelohde viscometer. After 5 ml of decalin was added to the decalin solution for dilution, the specific viscosity ηsp was measured in the same manner as described above. This dilution operation was further repeated twice, and the value of ηsp / C when the concentration (C) was extrapolated to 0 was determined as the intrinsic viscosity [η] (unit: dl / g) (see the following formula 1).
[Η] = lim (ηsp / C) (C → 0) Equation 1

[Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)]
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 determined by gel permeation chromatography (GPC: Gel). It calculated by the standard polystyrene conversion method using Permeation Chromatography). The measurement conditions are as follows.

~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

[Melt flow rate (MFR)]
The melt flow rate (MFR) of the polymer A was measured at 230 ° C. under a load of 2.16 kg in accordance with ASTM D1238. The unit is g / 10 min).

〔density〕
The density (kg / m ³ ) of the polymer A was measured according to JIS K7112 (density gradient tube method). This density (kg / m ³ ) was used as an indicator of lightness.

[Melting point (Tm)]
The melting point (Tm) of the polymer A was measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.) as a measuring device.
About 5 mg of Polymer A was sealed in a measurement aluminum pan and heated from room temperature to 200 ° C. at 10 ° C./min. In order to completely melt the polymer A, it was 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 was performed to 200 ° C. at 10 ° C./min. The peak temperature (° C.) at the second heating was defined as the melting point (Tm) of the polymer A. The melting point (Tm) of this polymer A was used as an index of heat resistance.

[Stress relaxation]
The powdered polymer A obtained above was charged into a hopper of a 20 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. The cylinder temperature was set to 100 ° C. to 250 ° C., the die temperature was set to 250 ° C., and the melt-kneaded product was extruded from the T die. The extruded melt-kneaded product was taken up at a chill roll temperature of 20 ° C. and a take-up speed of 10 m / min to obtain a cast film having a thickness of 50 μm. This cast film was cut out to 45 mm × 10 mm to obtain a test piece.
About this test piece, using a viscoelasticity measuring apparatus (MCR301, manufactured by Anton Paar), the dynamic viscoelasticity in the temperature range of −70 ° C. to 180 ° C. was measured at a frequency of 10 rad / s, and the glass transition temperature was caused. The maximum value (peak value) of the loss tangent (tan δ) to be measured and the temperature at which the maximum value is shown (temperature at the peak) were measured. This measurement was performed 3 days after the cast film was formed.
As described above, when the peak value of tan δ is 0.4 or more and the temperature at the peak is in the temperature range of −5 ° C. to 50 ° C., the stress relaxation property is excellent.

<Example 1>
[Production of expandable base film]
75 parts by mass of the polymer A-1 as the polymer A and 25 parts by mass of the following polymer B-1 as the polymer B were mixed (dry blended). Next, the obtained mixture was put into a hopper of a 20 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 cylinder temperature was set to 230 ° C., the die temperature was set to 250 ° C., the melt-kneaded product was extruded from the T die, and cast to obtain an expandable substrate film (hereinafter also simply referred to as “film”). .
In addition, the film formed that whose thickness is 50 μm and that whose thickness is 200 μm.

As the polymer B-1, Prime Polypro (registered trademark) F327 manufactured by Prime Polymer Co., Ltd. (propylene / ethylene / butene random copolymer, density: 907 kg / m ³ , MFR (230 ° C.): 7 g / 10 min) Was used.

[Evaluation]
The following evaluation (measurement) was performed on the polymer B and the expandable substrate film.

1. Measurement of type and content (mol%) of constituent unit as main component of polymer B For polymer B, the type and content (mol%) of constituent unit as main component are measured by ¹³ C-NMR. did. The details of the measurement conditions of ¹³ C-NMR, is similar to the measurement conditions ¹³ C-NMR in the measurement of the composition of the polymer A.
The results are shown in Table 2 below.

2. Measurement of Tensile Elastic Modulus (YM) and Tensile Breaking Elongation (EL) of Film A film having a thickness of 200 μm cut into a “test piece type 5” dumbbell shape conforming to JIS K7127 (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.
Then, 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].}
The above results are shown in Table 2 below.

3. Measurement of Elmendorf Tear Strength of Film A film having a thickness of 50 μm cut into a rectangular shape of 75 mm × 63 mm 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 .
The above results are shown in Table 2 below.

4). Measurement of stress relaxation rate of film A sheet having a thickness of 10 mm and a length of 100 mm punched out from a film having a thickness of 50 μm was used as a test piece.
Using a tensile tester (universal tensile tester 3380, manufactured by Instron), the test piece was stretched 10% under the conditions of a distance between chucks of 75 mm, a tensile speed of 200 mm / min, and a temperature of 23 ° C. And the stress (initial stress) at the time of extending | stretching 10% was measured, elongation of the test piece was hold | maintained as it was for 120 seconds, and the change of the stress in the meantime was also measured. The stress relaxation rate (%) was calculated from the difference between the initial stress and the stress 60 seconds after the elongation.
The above results are shown in Table 2 below.
The higher the stress relaxation rate, the better the stress relaxation property.

<Examples 2 to 10 and Comparative Examples 1 to 4>
In Example 1, the type of polymer A, the type of polymer B, and the content mass ratio [polymer A / polymer B] (in Table 2, expressed as “content mass ratio [A / B]”) The expandable substrate film was produced in the same manner as in Example 1 except that the combination was changed to the combination shown in Table 2 below, and the same evaluation as in Example 1 was performed.
The results are shown in Table 2.

-Description of Table 2-
Polymer B-1 Prime Polypro (registered trademark) F327 manufactured by Prime Polymer Co., Ltd. (propylene / ethylene / butene random copolymer, density: 907 kg / m ³ , MFR (230 ° C.): 7 g / 10 min )
Polymer B-2: Prime Polypro (registered trademark) F107 (Homopolypropylene, density: 910 kg / m ³ , MFR (230 ° C.): 7 g / 10 min) manufactured by Prime Polymer Co., Ltd.
Polymer B-3 Evolue (registered trademark) SP2540 manufactured by Prime Polymer Co., Ltd. (linear low density polyethylene, density: 924 kg / m ³ , MFR (190 ° C.): 3.8 g / 10 min)
Polymer B-4 Evolue (registered trademark) SP0540 (linear low density polyethylene, density: 903 kg / m ³ , MFR (190 ° C.): 3.8 g / 10 min) manufactured by Prime Polymer Co., Ltd.
Polymer B-5: Tuffmer (registered trademark) A0550S manufactured by Mitsui Chemicals, Inc. (ethylene / butene copolymer, density 860 kg / m ³ , MFR (190 ° C.) = 0.5 g / 10 min)

As shown in Table 2, in Examples 1 to 10, a high stress relaxation rate was maintained, and EL _MD / EL _TD and S _MD / S _TD were both values close to 1.0. Thereby, in Examples 1-10, it turned out that it is excellent in stress relaxation property, and the anisotropy of the tensile elongation at break and the anisotropy of tear strength are reduced.
On the other hand, in Comparative Examples 1 to 4, in which the structural unit that is the main component of the polymer B is a structural unit other than the structural unit (Y) in the polymer A (here, a structural unit derived from propylene), EL _MD / EL _TD and S _MD / S _TD were values separated from 1.0. Thereby, in Comparative Examples 1-4, it turned out that the anisotropy of tensile breaking elongation and the anisotropy of tear strength are large.

[Observation of film by transmission electron microscope (TEM)]
In addition, after the films of Examples 1 to 10 and Comparative Examples 1 to 4 were ground with a microtome in the cross-sectional direction to trim an ultra-thin section of the film cross section, one was selected by exposing to ruthenium tetroxide vapor for a certain period of time. Stained. When the produced samples were observed using a transmission electron microscope (TEM: Transmission Electron Microscope, model: H-7650) manufactured by Hitachi High-Tech, the films of Examples 1 to 10 and Comparative Examples 1 to 4 were It was confirmed to have a sea-island structure.

Claims (12)

70 to 95 mol% of structural unit (X) derived from 4-methyl-1-pentene, and a structural unit derived from an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene (Y ) Containing 5 mol% to 30 mol% of polymer A and polymer B having a content of the structural unit (Y) of 80 mol% to 100 mol%. When the total amount of the combined B is 90% by mass or more with respect to the total amount of the dicing film and the total amount of the polymer A and the polymer B is 100 parts by mass, the content of the polymer A is 20 A base material layer comprising an expandable base material film having a mass part of 90 parts by mass and a polymer B content of 10 parts by mass to 80 parts by mass;
The adhesive force measured according to JIS Z0237 when peeled from the surface of the SUS-304-BA plate after being stuck on the surface of the SUS-304-BA plate and left for 60 minutes is 0. An adhesive layer that is 1 N / 25 mm to 10 N / 25 mm;
With
A dicing film satisfying the following formula (2).
0.4 <= _SMD / _STD <= 1.5 ... Formula (2)
Wherein _{(2), S MD} represents the Elmendorf tear strength in the MD _{direction, S TD} shows Elmendorf tear strength in the TD direction. ] 70 to 95 mol% of structural unit (X) derived from 4-methyl-1-pentene, and a structural unit derived from an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene (Y ) In an amount of 5 mol% to 30 mol%, and a polymer B in which the content of the structural unit (Y) is 80 mol% to 100 mol%. When the total amount of the polymer B is 100 parts by mass, the content of the polymer A is 20 parts by mass to 75 parts by mass, and the content of the polymer B is 25 parts by mass to 80 parts by mass. A substrate layer comprising an expandable substrate film;
The adhesive force measured according to JIS Z0237 when peeled from the surface of the SUS-304-BA plate after being stuck on the surface of the SUS-304-BA plate and left for 60 minutes is 0. An adhesive layer that is 1 N / 25 mm to 10 N / 25 mm;
With
A dicing film satisfying the following formula (2).
0.4 <= _SMD / _STD <= 1.5 ... Formula (2)
Wherein _{(2), S MD} represents the Elmendorf tear strength in the MD _{direction, S TD} shows Elmendorf tear strength in the TD direction. ]   It is an intermediate layer disposed between the base material layer and the pressure-sensitive adhesive layer, and the tensile elastic modulus E (25) at 25 ° C. and the tensile elastic modulus E (60) at 60 ° C. are E (60) / E. (25) The dicing film according to claim 1 or 2, further comprising an intermediate layer satisfying a relationship of <0.1 and having the tensile elastic modulus E (25) of 1 MPa to 10 MPa.   The dicing film according to any one of claims 1 to 3, wherein the polymer A contains 70 to 90 mol% of the structural unit (X).   The dicing film according to any one of claims 1 to 4, wherein the structural unit (Y) is a structural unit derived from propylene. The dicing film according to any one of claims 1 to 5, which satisfies the following formula (1).
0.5 ≦ EL _MD / EL _TD ≦ 1.5 (1)
Wherein (1), _{EL MD} represents the tensile elongation at break in the MD direction, _{EL TD} indicates a tensile elongation at break in the TD direction. ] 70 to 95 mol% of structural unit (X) derived from 4-methyl-1-pentene, and a structural unit derived from an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene (Y ) Containing 5 mol% to 30 mol% of polymer A and polymer B having a content of the structural unit (Y) of 80 mol% to 100 mol%. When the total amount of the combined B is 90% by mass or more with respect to the total amount of the dicing film and the total amount of the polymer A and the polymer B is 100 parts by mass, the content of the polymer A is 20 A base material layer comprising an expandable base material film having a mass part of 90 parts by mass and a polymer B content of 10 parts by mass to 80 parts by mass;
The adhesive force measured according to JIS Z0237 when peeled from the surface of the SUS-304-BA plate after being stuck on the surface of the SUS-304-BA plate and left for 60 minutes is 0. An adhesive layer that is 1 N / 25 mm to 10 N / 25 mm;
A surface protective film for a semiconductor that satisfies the following formula (2) and protects the non-ground surface of the semiconductor substrate when the semiconductor substrate is ground.
0.4 <= _SMD / _STD <= 1.5 ... Formula (2)
Wherein _{(2), S MD} represents the Elmendorf tear strength in the MD _{direction, S TD} shows Elmendorf tear strength in the TD direction. ] 70 to 95 mol% of structural unit (X) derived from 4-methyl-1-pentene, and a structural unit derived from an α-olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene (Y ) In an amount of 5 mol% to 30 mol%, and a polymer B in which the content of the structural unit (Y) is 80 mol% to 100 mol%. When the total amount of the polymer B is 100 parts by mass, the content of the polymer A is 20 parts by mass to 75 parts by mass, and the content of the polymer B is 25 parts by mass to 80 parts by mass. A substrate layer comprising an expandable substrate film;
The adhesive force measured according to JIS Z0237 when peeled from the surface of the SUS-304-BA plate after being stuck on the surface of the SUS-304-BA plate and left for 60 minutes is 0. An adhesive layer that is 1 N / 25 mm to 10 N / 25 mm;
A surface protective film for a semiconductor that satisfies the following formula (2) and protects the non-ground surface of the semiconductor substrate when the semiconductor substrate is ground.
0.4 <= _SMD / _STD <= 1.5 ... Formula (2)
Wherein _{(2), S MD} represents the Elmendorf tear strength in the MD _{direction, S TD} shows Elmendorf tear strength in the TD direction. ] An adhering step of adhering the dicing film according to any one of claims 1 to 6 to a semiconductor substrate so that the semiconductor substrate and the adhesive layer face each other,
A dicing step of dicing the semiconductor substrate to which the dicing film is attached;
An expansion step for obtaining a plurality of semiconductor chips separated from each other by expanding the dicing film after the dicing step;
A pickup step of picking up at least one of the plurality of semiconductor chips;
A method for manufacturing a semiconductor device, comprising:   The method for manufacturing a semiconductor device according to claim 9, wherein in the attaching step, the dicing film is attached to the semiconductor substrate at a temperature of 40 ° C. to 80 ° C. and a pressure of 0.3 MPa to 0.5 MPa. The adhering step is a step of adhering the dicing film to a circuit forming surface of a semiconductor substrate in which a circuit is formed only on one surface so that the circuit forming surface and the adhesive layer face each other. ,
The method of manufacturing a semiconductor device according to claim 9, further comprising a grinding step of grinding a circuit non-formed surface of the semiconductor substrate after the attaching step and before the expanding step.
A groove forming step of forming a groove having a cut depth less than the thickness of the semiconductor substrate from a circuit forming surface of the semiconductor substrate on which a circuit is formed only on one surface;
The semiconductor surface protective film according to claim 7 or 8 is attached to a circuit formation surface of the semiconductor substrate in which the groove is formed so that the circuit formation surface and the pressure-sensitive adhesive layer face each other. A sticking process;
A grinding step of grinding a circuit non-formed surface of the semiconductor substrate to which the surface protective film for semiconductor is attached;
An expansion step of obtaining a plurality of semiconductor chips separated from each other by expanding the dicing film after the grinding step;
A pickup step of picking up at least one of the plurality of semiconductor chips;
A method for manufacturing a semiconductor device, comprising: