TW201912416A - Cutting substrate film - Google Patents

Abstract

A purpose of the present invention is to provide a substrate film for dicing having high heat resilience and excellent rack recovery properties. A further purpose of the present invention is to provide a substrate film for dicing in which a dicing film stretches uniformly even when expansion is performed under the condition of a low temperature. The substrate film for dicing comprises a surface layer/an intermediate layer/a back layer laminated in this order, wherein the surface layer and the back layer are composed of a resin composition including a polyethylene-based resin, and the intermediate layer is composed of a resin composition including a polyurethane-based resin.

Description

   Substrate film for cutting   

The present invention relates to a substrate film for dicing, which is used to attach and fix a semiconductor wafer when the semiconductor wafer is cut into a wafer shape.

The method for manufacturing a semiconductor wafer includes a method of manufacturing a large-area semiconductor wafer in advance, then cutting (cutting and separating) the semiconductor wafer into a wafer shape, and finally picking up the cut wafer. The cutting method of semiconductor wafers. In recent years, it has been known that the laser processing device uses a laser processing device, and does not contact the semiconductor wafer and directly cuts (breaks off) the semiconductor wafer.

The method of improving the cut-off (breakability) of semiconductor wafers by invisible laser wafer cutting is to suppress the solder crystal film provided on the dicing tape by expanding at a low temperature of -15 to 5 ° C. This method of extending and increasing the stress is widely known as a wafer processing tape (Patent Documents 1 and 2) which can well cut (break) a semiconductor wafer and a solder crystal film together.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-185584

[Patent Document 2] Japanese Patent Laid-Open No. 2015-185591

An object of the present invention is to provide a base film for cutting, which has high resilience to heat and excellent rack recoverability.

It is a further object of the present invention to provide a base film for cutting which can be uniformly stretched even if it is expanded under low temperature conditions.

The present invention further aims to provide a substrate film for dicing, which is used to cut (separate) the semiconductor wafer and the solder crystal layer after the invisible laser wafer dicing (laser dicing), even under low temperature conditions ( -15 ~ 5 ℃) and expansion under high speed conditions can still be well extended.

In a semiconductor production line, it is generally desirable to temporarily store the sheet (including the dicing film of the dicing base film) remaining in the product during processing after the expansion step in a rack for temporary storage. At this time, if the sheet is always in a relaxed state, the rack may not be well stored, and products may collide with each other to cause defects. This rack is the name used by the industry, others are also called zipper or shell.

To solve this problem, it is necessary to eliminate the slack of the sheet after the expansion step. As a method, a heat shrinkage technology (heat shrinkage recovery technology) currently exists. This is because the slack portion generated by the expansion step is heated to shrink the portion, thereby eliminating the slacker (that is, the recovery rate by heating and shrinking is high).

For example, it is required that even if the expansion is performed at a low temperature of -15 to 5 ° C, the dicing film can be stretched uniformly, and the semiconductor wafer can be cut well.

Further, for example, even after the invisible laser wafer is diced, in addition to the aforementioned low temperature conditions, expansion is also performed under high speed conditions, the dicing film is required to be uniformly extended, and the semiconductor wafer and the solder can be well cut (divided).晶 层。 Crystal layer.

The present inventors have conducted intensive studies in order to solve the above problems.

It was found that the substrate film for cutting includes the following surface layer / intermediate layer / inner layer laminated sequentially, and because the intermediate layer uses a polyurethane resin, the sheet after the expansion step (including the substrate film for cutting) The slack of the cutting film can be well eliminated by the heat shrinkage technology (heat shrinkage recovery technology).

It was found that the aforementioned dicing base film can be uniformly stretched even if it is expanded under low temperature conditions. It was found that, in addition to the low-temperature conditions, the aforementioned dicing base film can be stretched well when the expansion is performed under high-speed conditions.

Item 1.

A base film for cutting, which is a base film for cutting comprising a surface layer / intermediate layer / inner layer sequentially laminated, and is characterized in that the surface layer and the inner layer are made of a resin composition containing a polyethylene resin; The layer is made of a resin composition containing a polyurethane resin.

Item 2.

The base film for dicing according to item 1, wherein the surface layer and / or the back layer are a single layer or a plurality of layers.

Item 3.

The base film for dicing according to item 1 or 2, wherein the polyethylene-based resin is selected from branched low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-acetic acid. Vinyl ester copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl methacrylate copolymer (EMMA), ethylene- Resin of at least one of the group consisting of methacrylic acid interpolymer (EMAA) and ionomer resin.

Item 4.

The base film for dicing according to any one of items 1 to 3, wherein the polyurethane resin is a thermoplastic polyurethane resin (TPU).

Item 5.

A dicing film is characterized in that a dicing film in which an adhesive layer and a solder crystal layer are sequentially arranged on the surface layer side of the dicing base film according to any one of the foregoing items 1 to 4.

By using the dicing base film of the present invention, the used dicing film can be recovered to the rack more quickly and easily. That is, the dicing base film of the present invention has high resilience when exposed to heat, that is, it exhibits good heat shrinkability, and has excellent rack recyclability.

With the dicing base film of the present invention, the dicing film can be uniformly stretched even if it is expanded under low temperature conditions.

Using the dicing substrate film of the present invention, for example, when cutting a semiconductor wafer and a die bond layer after the invisible laser wafer is diced, the dicing is performed even if the expansion is performed under low temperature conditions and high speed conditions. The film also stretches well.

The present invention relates to a base film for cutting.

Further, the present invention relates to a dicing film, in which an adhesive layer and a solder crystal layer are sequentially disposed on a dicing base film.

(1) Cutting base film

The cutting base film of the present invention is characterized in that it comprises a structure in which a surface layer, an intermediate layer and an inner layer are sequentially laminated.

The surface layer and / or the back layer are preferably a single layer or a plurality of layers.

Hereinafter, each layer which comprises the dicing base film of this invention is demonstrated in detail.

(1-1) Surface layer

The surface layer is made of a resin composition containing a polyethylene resin.

The polyethylene resin contained in the surface layer is selected from branched low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), and ethylene-methyl acrylate. Interpolymer (EMA), ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMAA), and ionomer resin It is preferred that at least one of the constituents in the group is included.

Since the surface layer is made of a resin composition containing at least one of these components, the slicing of the base film for cutting, that is, the tensile strength of the base material is excellent.

In addition, as long as the effect of the present invention is not impaired, a polypropylene resin may be blended.

The melt flow rate (MFR) of the ethylene-vinyl acetate copolymer (EVA) at 190 ° C is only about 30 g / 10 minutes or less, preferably about 20 g / 10 minutes or less, and more preferably about 15 g / 10 minutes or less. It is more preferably about 10 g / 10 minutes or less. By setting the MFR to 10 g / 10 minutes or less, it is possible to suppress a difference in viscosity from the intermediate layer and to form a film stably.

In addition, in order to facilitate the extrusion of the resin, the MFR of EVA is preferably about 0.1 g / 10 minutes or more, and more preferably about 0.3 g / 10 minutes or more.

The density of EVA is preferably about 0.9 to 0.96 g / cm ^{3, and more} preferably about 0.92 to 0.94 g / cm ³ .

The melt flow rate (MFR) of the branched low density polyethylene (LDPE) at 190 ° C is preferably about 10 g / 10 minutes or less, and more preferably about 6 g / 10 minutes or less. By setting the MFR to 10 g / 10 minutes or less, it is possible to suppress a difference in viscosity from the intermediate layer and to form a film stably.

In addition, the MFR of LDPE is preferably about 0.1 g / 10 minutes or more, and more preferably about 0.3 g / 10 minutes or more in order to facilitate the extrusion of the resin.

The density of LDPE is preferably about 0.9 to 0.94 g / cm ^{3, and more} preferably about 0.91 to 0.93 g / cm ³ .

The melt flow rate (MFR) of the linear low-density polyethylene (LLDPE) at 190 ° C is preferably about 10 g / 10 minutes or less, and more preferably about 6 g / 10 minutes or less. By setting the MFR to 10 g / 10 minutes or less, it is possible to suppress a difference in viscosity from the intermediate layer and to form a film stably.

In addition, the MFR of LLDPE is preferably about 0.1 g / 10 minutes or more, and more preferably about 0.3 g / 10 minutes or more in order to facilitate the extrusion of the resin.

The density of LLDPE is preferably about 0.9 to 0.94 g / cm ^{3, and more} preferably about 0.91 to 0.93 g / cm ³ .

Here, the melt flow rate (MFR) is obtained according to ISO 1133, and the density is obtained according to ISO 1183-1: 2004.

The surface layer may further contain an antistatic agent as necessary. The antistatic agent that can be used in the aforementioned surface layer can also be used in the surface layer. The antistatic agent used in the surface layer may be selected from conventional surfactants such as anionic, cationic, and nonionic, and is particularly based on the viewpoints of durability and durability, such as PEEA resin and hydrophilic PO resin. Nonionic surfactants are preferred.

When the surface layer contains an antistatic agent, the content of the antistatic agent is preferably about 5 to 25% by weight, and more preferably about 7 to 22% by weight in the resin composition of the surface layer. By blending the antistatic agent within the aforementioned range, even if the same expansion occurs due to contact with the expansion ring, the sliding properties of the surface layer are not impaired.

In addition, since semiconductivity can be effectively provided, the generated static electricity can be quickly removed. For example, the substrate film for cutting of the present invention containing the antistatic agent in the above range has a surface resistivity of about 10 ⁷ to 10 ¹² Ω / □.

An anti-adhesive agent may be further added to the surface layer. The addition of an anti-adhesive agent is preferable because it can suppress the adhesion when the base film for cutting is rolled into a roller shape. Examples of the anti-adhesive agent include inorganic or organic fine particles.

(1-2) Inside

The inner layer, like the surface layer, is made of a resin composition containing a polyethylene resin.

The polyethylene resin used in the surface layer may be used, or a polyethylene resin different from the surface layer may be used.

In addition, if necessary, the surface layer may contain an antistatic agent or an anti-adhesive agent.

In the dicing base film of the present invention, the surface layer and / or the back layer may be a single layer or a plurality of layers. The cutting base film of the present invention may be provided with a plurality of surface layers and / or back layers as necessary.

When the surface layer and / or the inner layer are plural layers, the surface layer-1, the surface layer-2, the surface layer-3, and ． ． Indicates, in addition, from the innermost layer side, the inner layer-1, the inner layer-2, the inner layer-3, and. ． ． Means.

(1-3) middle layer

The intermediate layer is made of a resin composition containing a polyurethane resin (PU).

The PU is preferably a thermoplastic polyurethane resin (TPU).

The base film for dicing has an intermediate layer formed of a resin composition containing a polyurethane resin (PU), thereby improving the swellability.

The substrate film for dicing has an intermediate layer formed of a resin composition containing a polyurethane resin (PU). In the case of breaking), the dicing film can be stretched well even when the expansion is performed under low temperature conditions and high speed conditions.

(i) Polyurethane resin (PU)

The polyurethane resin (PU) is preferably a thermoplastic polyurethane resin (TPU). TPU is obtained by reacting polyisocyanate, polyol and chain elongation agent. It is a block polymerization of the soft segment formed by the reaction of polyol and polyisocyanate and the hard segment formed by the reaction of chain extender and polyisocyanate Thing.

Examples of the polyisocyanate include: diphenylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, and benzenedimethylene diisocyanate. Wait. Among these, diphenylmethane diisocyanate and / or hexamethylene diisocyanate are preferred from the viewpoint of abrasion resistance of a thermoplastic polyurethane resin.

Examples of the polyol include polytetramethylene ether glycol, polyester polyol, and lactone-based polyester polyol. Polyester polyols are obtained by the polycondensation reaction of a dicarboxylic acid and a diol.

Specific examples of diols used in the production of polyester polyols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. Etc., these alone or in combination.

Examples of the dicarboxylic acid used in the present invention include adipic acid, sebacic acid, and the like, and these may be used alone or in combination.

Among these polyols, polytetramethylene ether glycol is preferred from the viewpoint that a thermoplastic polyurethane resin can obtain high impact resistance. The number average molecular weight of the related polyol is preferably 1,000 to 4,000, and the number average molecular weight is particularly preferably 2,000 to 3,000.

Examples of the chain elongating agent include aliphatic linear diols having 2 to 6 carbon atoms, such as ethylene glycol, 1,4-butanediol, and 1,6-hexanediol; and hydroquinone Dihydroxyethyl ether and so on. It can also be used in combination with amines such as hexamethylenediamine, isophoronediamine, toluenediamine, and monoethanolamine. Among these, from the viewpoint of the abrasion resistance of the thermoplastic polyurethane resin, an aliphatic linear diol having 2 to 6 carbon atoms is preferred.

The density of the thermoplastic polyurethane resin is preferably about 1.1 to 1.5 g / cm ^{3, and more} preferably about 1.1 to 1.3 g / cm ³ .

The thermoplastic polyurethane resin can be produced by a known method such as a one-step method or a prepolymer method of the aforementioned raw materials.

Examples of PU include PANDEX manufactured by DIC Covestro Polymer Ltd., Miractran manufactured by Nippon Miractran Co, Ltd., and the like.

The intermediate layer and the resin composition constituting the intermediate layer may include (ii) a polyethylene-based resin in addition to the (i) PU described above.

(ii) Polyethylene resin

As the polyethylene resin, a resin that can be used for the surface layer can be used.

The same resin as the polyethylene resin used in the surface layer may be used for the intermediate layer, and a resin different from the polyethylene resin used in the surface layer may be used. As the polyethylene resin, it is preferable to use the above-mentioned PU plus an ethylene-methacrylic acid copolymer (EMAA).

The content ratio when the intermediate layer contains a polyethylene resin is preferably 0 to 80% by weight, and more preferably 0 to 70% by weight.

As long as the polyethylene-based resin is in the range of 0 to 80% by weight, it has good swellability, that is, tensile properties, of the base film for cutting.

(1-4) Layer structure of base film for cutting

The dicing base film of the present invention includes a surface layer, an intermediate layer, and an inner layer which are sequentially laminated.

The surface layer is a layer located on the contact side of the wafer and in contact with the adhesive layer.

The intermediate layer may be formed of a single layer (single layer) by each resin, or a layer (single layer) of a resin mixture, or each layer (multilayer) of each resin.

In the dicing base film of the present invention, the surface layer and / or the back layer are preferably a single layer or a plurality of layers. The front and back layers, LDPE, EVA, etc., can be formed from each resin (single layer), or a mixture of resins (single layer), and each layer (multilayer) from each resin.

The overall thickness of the substrate film for cutting of the present invention is preferably about 50 to 300 μm, more preferably about 70 to 200 μm, and even more preferably about 80 to 150 μm. By setting the entire thickness of the dicing base film to 50 μm or more, the semiconductor wafer can be protected from being washed out when the semiconductor wafer is cut.

Relative to the full thickness of the substrate film for cutting, the thickness ratio of the surface layer and the back layer is preferably about 4 to 80%, and more preferably about 10 to 60%.

The ratio of the thickness of the intermediate layer to the full thickness of the substrate film for cutting is preferably about 20 to 96%, and more preferably about 40 to 90%.

A specific example of the base film for dicing is a case where the full thickness of the base film for dicing is 60 to 100 μm.

The thickness of the surface layer and the back layer is preferably about 2 to 44 μm each, and more preferably about 10 to 38 μm each. When the surface layer and the back layer are plural layers, the total thickness may be formed by forming each layer within the above-mentioned thickness range.

The thickness of the intermediate layer is preferably about 12 to 96 μm, and more preferably about 24 to 80 μm. When the intermediate layer is a plurality of layers, the total thickness may be formed by forming each layer within the thickness range described above.

Example of 3 types and 5 layers (Surface-1 / Surface-2 / Intermediate / Inner-2 / Inner-1)

Examples of three types of five layers. As mentioned above, the total thickness of surface layer-1 and surface layer-2 is within the thickness of the surface layer. Similarly, the total thickness of inner layer-1 and inner layer-2 is in the inner layer. Range of thickness.

As the surface layer-1 and the surface layer-2, the same type of polyethylene resin can be used, and different types of polyethylene resin can also be used.

The inner layer-1 and the inner layer-2 can use the same kind of polyethylene resin, and different kinds of polyethylene resin can also be used.

When the same type of polyethylene resin is used, for example, when EVA is used, the EVA used for the surface layer-2 and the inner layer-2 is compared with the EVA used for the surface layer-1 and the inner layer-1. EVA with a higher content (VA content) is preferred.

For the surface layer-1 and the inner layer-1, it is better to use EVA with a VA content of about 5 to 15% by weight, and it is better to use about 7 to 13% by weight of EVA.

For surface layer-2 and inner layer-2, it is better to use EVA with a VA content of about 15 to 33% by weight, and it is better to use about 28 to 33% by weight of EVA.

In addition, from the viewpoint of MFR, the EVA used for the surface layer-2 and the inner layer-2 is better than the surface layer-1 and the inner layer-1, which uses EVA with a higher melt flow rate (MFR).

For the surface layer-1 and the inner layer-1, the MFR of EVA at 190 ° C is preferably about 0.1g / 10 minutes to 10g / 10 minutes, and preferably about 5g / 10 minutes to 10g / 10 minutes.

For the surface layer-2 and the inner layer-2, the MFR of EVA at 190 ° C is preferably about 10g / 10 minutes to 40g / 10 minutes, and preferably about 12g / 10 minutes to 35g / 10 minutes.

(2) Manufacturing method of substrate film for cutting

The substrate film for cutting the surface layer / intermediate layer / inner layer can be produced by multi-layer co-extrusion molding of the resin composition for the surface layer, the intermediate layer, and the inner layer. Specifically, the resin composition for the surface layer, the resin composition for the intermediate layer, and the resin composition for the back layer can be produced by co-extrusion molding as a surface layer / intermediate layer / back layer in order.

Further, when the surface layer and the inner layer are composed of a plurality of layers, the resin composition for each surface layer and the inner layer may be separately charged into the extruder. For example, the surface layer-1 / surface layer-2 / intermediate layer / inner layer-2 may be used. / Inner layer-1 is sequentially laminated and co-extruded.

The resin composition constituting the surface layer may further be added with an antistatic agent as necessary. The same goes for the inner layer.

The above-mentioned resins for each layer are sequentially supplied to the screw extruder, and the film is extruded from the multilayer T die at 180 to 240 ° C, and cooled by a cooling roller at 30 to 70 ° C in a substantially non-extended state. take out. Alternatively, after temporarily pelletizing the resin for each layer, extrusion molding may be performed as described above.

There is virtually no elongation at the time of taking out, in order to effectively expand the film after cutting. This substantial non-elongation includes no elongation, or a slight extension that does not adversely affect the expansion of the dicing film. Generally, when the film is taken out, it is sufficient as long as it does not cause slack in stretching.

(3) Manufacturing of cutting film

The dicing film of the present invention can be produced according to a conventional technique. For example, a solvent such as an organic solvent is used to dissolve the adhesive constituting the adhesive layer, and apply the solvent to the substrate film for dicing, and remove the solvent to obtain a film composed of the substrate film / adhesive layer.

The resin composition constituting the solder crystal layer is dissolved in a solvent such as an organic solvent, applied to another film (peeling film), and the solvent is removed to prepare a solder crystal film.

Further, the adhesive layer and the solder crystal layer are oppositely overlapped to form a dicing film. Thereby, a thin film composed of a base film, an adhesive layer, and a solder crystal layer can be obtained. The solder crystal layer at this stage is bonded to the semiconductor wafer and the adhesive layer in a weak (pseudo-) adhesive state.

After the expansion, the separated semiconductor wafer and solder crystal layer are laminated with a predetermined package or semiconductor wafer, and overheated to a temperature where the solder crystal layer is strongly adhered, thereby continuing.

[Example]

Hereinafter, the present invention is described in detail by examples, but the present invention is not limited to these examples.

(1) Raw material for cutting substrate film

Table 1 shows the raw materials of the base film for cutting.

[Description of abbreviation]

PE-1 ~ 9: Polyethylene resins 1 ~ 9

SEBS: hydrogenated styrene-butadiene interpolymer

(Styrene-ethylene-butene-styrene copolymer)

TPU: Thermoplastic Polyurethane (PU)

Amorphous PO: Amorphous polyolefin

LDPE: branched low density polyethylene

EVA: ethylene-vinyl acetate copolymer

VA content: the proportion of vinyl acetate

EMAA: ethylene-methacrylic acid copolymer

MAA content: methacrylic acid content

St content: the proportion of styrene

(Content of vinyl aromatic hydrocarbon (St) component in vinyl aromatic hydrocarbon resin)

(2) Manufacture of base film for cutting of surface layer / intermediate layer / inner layer

Based on the surface layer / intermediate layer / back layer (three layers) described in Table 2, the resin composition was blended with each component and composition to produce a base film for cutting.

The resin composition constituting each layer is respectively put into an extruder adjusted to 220 ° C, and the surface layer / intermediate layer / inner layer is sequentially extruded and laminated in a T mold of 220 ° C, and extruded on a cooling roll having a cooling water circulation of 30 ° C Thus, a sheet-like three-layer film was obtained.

(3) Manufacture of base film for cutting of surface layer-1 / surface layer-2 / intermediate layer / inner layer-2 / inner layer-1

Based on the surface layer-1 / surface layer-2 / intermediate layer / inner layer-2 / inner layer-1 (5 layers) described in Tables 3 and 4, the resin composition was compounded with each component and composition to produce a substrate film for cutting.

Put the resin composition constituting each layer into an extruder adjusted to 220 ° C, and the surface layer-1 / surface layer-2 / intermediate layer / inner layer-2 / inner layer-1 are sequentially extruded and laminated at 220 ℃ T, It was co-extruded on a cooling roll with 30 ° C cooling water circulation to obtain a sheet-like five-layer film.

(4) Evaluation of substrate film for cutting

(4-1) Low temperature expansion (Ex)

<Evaluation method>

(Measurement of tensile elongation)

The MD direction of the film (extrusion direction of film forming) and TD direction (width direction of the film formed by film forming) are processed at a stretching speed of 200 mm / min, and the processing is 10 mm wide and the distance between the chucks is A film sample of 40 mm was used to measure the tensile elongation of the film.

(Measurement of 25% modulus)

The MD direction of the film (extrusion direction for film formation) and TD direction (width direction of the film formed by film formation) are processed at a stretching speed of 200 mm / min, using a 10 mm width and a distance between the chucks of For a 40 mm film sample, an SS curve (stress-strain curve) was obtained.

Read the stress values of the obtained SS curves at 25% elongation.

<Evaluation Criteria>

(I) Low temperature expansion (low temperature Ex)

○: When a tensile test is performed, the elongation is 100% or more.

×: When the tensile test was performed, the film elongation did not reach 100%.

(Two) uniform expansion (uniform Ex)

The ratio of the stress value at 25% elongation in the MD direction to the stress value at 25% elongation in the TD direction was determined as the modulus ratio (MD / TD).

：: The modulus ratio (MD / TD) is less than 1.5.

×: The modulus ratio (MD / TD) is 1.5 or more.

When the modulus ratio (MD / TD) is in the aforementioned range, the substrate film for cutting can exhibit good uniform expansion property (uniform ex property) under a low temperature condition of -15 to 5 ° C.

(4-2) Low temperature and high speed expansion (low temperature and high speed Ex)

<Evaluation method>

(Measurement of fracture extension (maximum extension) (%))

Tensile test: "HYDROSHOT.HITS-T10" manufactured by Shimadzu Corporation was used to extend the MD direction and TD direction of the film sample to break at -15 ± 2 ° C at a tensile speed of 250 mm / sec. The film sample was processed to a width of 25 mm and a distance between the chucks of 10 mm.

Based on the data graph of load and extension, the SS curve (stress-strain curve) was made to calculate the fracture extension (maximum extension).

<Evaluation Criteria>

(Evaluation of high-speed tensile test (mechanical characteristics))

○: The tensile elongation at break in the MD and TD directions is 120% or more.

×: The tensile elongation at break in the MD and TD directions did not reach 120%.

In this evaluation method, a tensile test is performed by setting the tensile speed to 250 mm / sec. In addition to the low temperature conditions, the swellability under high speed conditions is also evaluated. In addition, the film can be stretched to 120% or more in the MD and TD directions. For example, after the invisible laser wafer is diced, the film can be expanded under low temperature conditions (-15 to 5 ° C) and high speed conditions. Extends well.

(4-3) Heat shrinkability (HS properties)

Condition 1-Tensile test: "AUTOGRAPH AG-500NX TRAPEZIUM X" manufactured by Shimadzu Corporation was used, under the environment of -15 ± 2 ° C, at a tensile speed of 200 mm / min, the MD direction and TD direction of the film sample The film samples were stretched by 200%, and the film samples were processed to a width of 10 mm and a distance between the chucks of 40 mm.

Condition 2-Shrinkage test: A "hygrostat TBP105DA" manufactured by Mitsubishi Heavy Industries Co., Ltd. was used, and the sample was heated for 5 seconds at a set temperature of 80 ° C.

<Evaluation method>

A strip-shaped film sample having a length of 100 mm (a space between the marking lines + an end portion (30 mm above and below)) and a width of 10 mm was prepared and stretched under the conditions 1 described above.

After holding at 200% elongation for 10 seconds, return the chuck to its original position, release the chuck, and shrink the sample under Condition 2 above.

The interval L [mm] after the shrinkage was measured, and the recovery rate was calculated by the following formula.

Response rate [%] = {(120-L) / 80} × 100

The MD and TD directions were used to measure the recovery rate, and this was designated as heat shrinkage (HS).

<Evaluation Criteria>

(A) heat shrinkability (HS)

○: After heat shrinkage, the recovery rate was 70% or more.

The response rate is preferably 90 ~ 110%.

×: After heat shrinkage, the recovery rate was less than 70%.

When the recovery rates in the MD and TD directions are within the aforementioned ranges, the base film for dicing can exhibit good heat shrinkability (HS properties) in an environment of 80 ° C.

(Two) uniform heat shrinkability (uniform HS)

○: The ratio of the recovery rate in the MD direction to the recovery rate in the TD direction (MD / TD) is less than 1.2.

The response rate ratio (MD / TD) is preferably 0.9 to 1.15.

×: The ratio of response rate (MD / TD) is 1.2 or more.

When the recovery ratio (MD / TD) is within the aforementioned range, the base film for dicing can exhibit good uniform heat shrinkability (uniform HS property) under the condition of 80 ° C.

The dicing base film (Examples 1 to 12) of the present invention can be uniformly stretched even if it is expanded under low temperature conditions.

Compared with the comparative example, the value of the heat shrinkability (HS property) of the base film for dicing of the present invention (Example) is significantly larger. That is, the base film for dicing of the present invention has good heat shrinkability.

Any of the low-temperature expansion properties (Ex properties), the dicing base film of the present invention (examples) and the comparative examples is within an allowable range.

Compared with the comparative example, the base film for dicing of this invention (Example) has a low-temperature high-speed expansion property (low-temperature high-speed Ex property).

(5) Inspection

Heat shrinkability

With the dicing base film of the present invention, even if the dicing film (sheet) is subjected to the expansion step, the generated slack portion can be contracted by heating the slack portion, thereby eliminating slack.

The dicing base film of the present invention, particularly a dicing film (sheet), has a high recovery rate by heat shrinkage.

By using the dicing base film of the present invention, the used dicing film can be recovered to the rack more quickly and easily. That is, the dicing base film of the present invention has high resilience to heat, and the dicing film can be recovered uniformly. That is, the heat shrinkability is exhibited well, and the rack recyclability is excellent. In addition, products using the dicing base film of the present invention do not conflict with each other and do not cause defects.

Expansive

Using the dicing base film of the present invention, even if expansion is performed under low temperature conditions, the swellability is good, and the dicing film can be uniformly stretched. By using the dicing base film of the present invention and performing expansion under a low temperature condition, the semiconductor wafer and the die bond layer can be well cut (divided) together.

When the substrate film for dicing of the present invention is used, in particular, after the invisible laser wafer is diced, the semiconductor wafer and the die bond layer are cut (separated), the expansion is good even when the expansion is performed at low temperature and high speed The cutting film can be extended well. By using the dicing base film of the present invention, even if expansion is performed under low-temperature conditions and high-speed conditions, the semiconductor wafer and the die bond layer can be well cut (separated) together.

The use of the dicing base film of the present invention can be expanded while the semiconductor products continue to be miniaturized, and the sheet is being re-expanded (expandable). Higher shrinkage sheet.

Claims (5)

    A base film for cutting, which is a base film for cutting comprising a surface layer / intermediate layer / inner layer sequentially laminated, and is characterized in that the surface layer and the inner layer are made of a resin composition containing a polyethylene resin; The layer is made of a resin composition containing a polyurethane resin.         The substrate film for dicing according to item 1 of the patent application scope, wherein the surface layer and / or the back layer are a single layer or a plurality of layers.         The cutting base film according to item 1 or 2 of the scope of patent application, wherein the polyethylene resin is selected from branched low density polyethylene (LDPE), linear low density polyethylene (LLDPE), Ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl methacrylate copolymer (EMMA) , Ethylene-methacrylic acid copolymer (EMAA), and at least one of the resins in the group.         The substrate film for dicing according to any one of claims 1 to 3, wherein the polyurethane resin is a thermoplastic polyurethane resin (TPU).         A dicing film is characterized in that the dicing film of an adhesive layer and a solder crystal layer is sequentially arranged on the surface layer side of the dicing base film described in any one of claims 1 to 4 of the scope of application for a patent.