JPWO2019039253A1 - Base film for dicing - Google Patents

Abstract

An object of the present invention is to provide a base film for dicing, which has high heat recoverability and excellent rack recoverability. Another object of the present invention is to provide a base film for dicing, in which the dicing film uniformly extends even when expanded under low temperature conditions. A dicing substrate film having a structure in which a surface layer/intermediate layer/back layer are laminated in this order, wherein the surface layer and the back layer are made of a resin composition containing a polyethylene resin, and the intermediate layer is a resin composition containing a polyurethane resin. A substrate film for dicing, which comprises

Description

The present invention relates to a base film for dicing, which is used by being stuck and fixed to a semiconductor wafer when dicing the semiconductor wafer into chips.

As a method of manufacturing a semiconductor chip, there is a method of manufacturing a semiconductor wafer in a large area in advance, then dicing (cutting and separating) the semiconductor wafer into chips, and finally picking up the diced chips. As a method of cutting a semiconductor wafer, stealth dicing is known in recent years, which uses a laser processing apparatus to cut (divide) the semiconductor wafer without contacting the semiconductor wafer.

As a method for improving the cuttability (separability) of a semiconductor wafer by stealth dicing, by expanding under a low temperature condition of -15 to 5°C, the elongation of the die bond film provided on the dicing tape is suppressed, and There is known a tape for wafer processing in which a semiconductor wafer and a die bond film are satisfactorily cut (separated) together by a method of increasing stress (Patent Documents 1 and 2).

JP 2015-185584 JP JP 2015-185591 JP

It is an object of the present invention to provide a dicing substrate film that has high heat recoverability and excellent rack recoverability.

It is another object of the present invention to provide a dicing substrate film that stretches uniformly even when expanded under low temperature conditions.

The present invention, even after performing the stealth dicing (laser dicing), when cutting (dividing) the semiconductor wafer and the die bond layer, even if expanded under low temperature conditions (-15 to 5°C) and high speed conditions, An object is to provide a base film for dicing which stretches.

In a semiconductor manufacturing line, it is desired to temporarily store a sheet (a dicing film including a dicing substrate film) in which a product in the middle of processing after the expanding step remains in a rack. At that time, if the slack remains on the sheet, it tends to lead to problems such as not being able to be properly stored in the rack, collision between products, and defects. The rack is a name used in the industry, and is also called a zipper, a case, or the like.

In order to solve this, it is necessary to eliminate the slack of the sheet after the expanding process. As a method therefor, there is a heat shrink technology (heat shrinkage restoration technology). This is to heat the slack portion generated by the expanding step to shrink the slack portion and eliminate the slack (that is, the restoration rate by heat shrinkage is high).

For example, even when the expanding is performed under a low temperature condition of −15 to 5° C., it is required that the dicing film uniformly stretches and the semiconductor wafer be cut well.

Further, for example, after stealth dicing, in addition to the low temperature condition, even when the expansion is performed under high speed conditions, the dicing film is well stretched, and the semiconductor wafer and the die bond layer are well cut (divided). Is required.

The present inventor has conducted earnest research to solve the above problems.

The dicing substrate film includes a structure in which the following surface layer/intermediate layer/back layer are laminated in this order, and by using a polyurethane-based resin for the intermediate layer, a sheet after the expanding step (a dicing film including the dicing substrate film) It has been found that the slack of swelling is satisfactorily solved by the heat shrink technology (heat shrinkage restoration technology).

It has been found that the dicing base film uniformly stretches even when expanded under low temperature conditions. It has been found that the base film for dicing expands well even when the dicing film is expanded under high-speed conditions in addition to low-temperature conditions.

Item 1.
A substrate film for dicing, comprising a structure in which a surface layer/intermediate layer/back layer are laminated in this order, wherein the surface layer and the back layer are made of a resin composition containing a polyethylene resin,
The intermediate layer is made of a resin composition containing a polyurethane resin,
Base film for dicing.

Item 2.
Item 2. The dicing substrate film according to Item 1, wherein the surface layer and/or the back layer is a single layer or a multilayer.

Item 3.
The polyethylene resin is branched low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene- At least one resin selected from the group consisting of ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMAA), and ionomer resin. The base film for dicing according to item 1 or 2, which is

Item 4.
Item 4. The dicing substrate film according to any one of Items 1 to 3, wherein the polyurethane resin is a thermoplastic polyurethane resin (TPU).

Item 5.
A dicing film having a pressure-sensitive adhesive layer and a die bond layer provided in this order on the surface layer side of the dicing substrate film according to any one of Items 1 to 4.

By using the dicing substrate film of the present invention, the used dicing film can be collected in the rack more quickly and easily. That is, the dicing substrate film of the present invention has high heat-restorability, that is, excellent heat shrinkability, and excellent rack recoverability.

When the base film for dicing of the present invention is used, the dicing film is uniformly stretched even when expanding is performed under low temperature conditions.

When the substrate film for dicing of the present invention is used, for example, after stealth dicing, when cutting (dividing) the semiconductor wafer and the die bond layer, even when the expanding is performed under low temperature conditions and high speed conditions, the dicing film is Stretches well.

The present invention relates to a dicing substrate film.

Furthermore, the present invention relates to a dicing film in which a pressure-sensitive adhesive layer and a die bond layer are provided in this order on a dicing substrate film.

(1) Dicing substrate film The dicing substrate film of the present invention comprises
It is characterized by including a structure in which the surface layer/intermediate layer/back layer are laminated in this order.

It is preferable that the surface layer and/or the back layer is a single layer or multiple layers.

Hereinafter, each layer constituting the dicing substrate film of the present invention will be described in detail.

(1-1) Surface layer The surface layer is made of a resin composition containing a polyethylene resin.

As the polyethylene resin contained in the surface layer, branched low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA) At least one selected from the group consisting of an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, an ethylene-methyl methacrylate copolymer (EMMA), an ethylene-methacrylic acid copolymer (EMAA), and an ionomer resin. Preference is given to using seed components.

Since the surface layer is made of the resin composition containing at least one of these components, the expandability of the dicing substrate film, that is, the tensile properties of the substrate are excellent.

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

The melt flow rate (MFR) of ethylene-vinyl acetate copolymer (EVA) at 190° C. may be about 30 g/10 minutes or less, preferably about 20 g/10 minutes or less, more preferably about 15 g/10 minutes or less. It is preferably about 10 g/10 minutes or less. By setting the above MFR to 10 g/10 minutes or less, the viscosity difference with the intermediate layer can be suppressed, and stable film formation becomes possible.

Further, the MFR of EVA is preferably about 0.1 g/10 min or more, more preferably about 0.3 g/10 min or more in order to facilitate extrusion of the resin.

The density of EVA is preferably about 0.9~0.96g / cm ^3, about 0.92~0.94g / cm ³ is more preferable.

The melt flow rate (MFR) of branched low-density polyethylene (LDPE) at 190° C. is preferably about 10 g/10 minutes or less, more preferably about 6 g/10 minutes or less. By setting the above MFR to 10 g/10 minutes or less, the viscosity difference with the intermediate layer can be suppressed, and stable film formation becomes possible.

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

The density of LDPE is preferably about 0.9~0.94g / cm ^3, about 0.91~0.93g / cm ³ is more preferable.

The melt flow rate (MFR) of linear low-density polyethylene (LLDPE) at 190° C. is preferably about 10 g/10 minutes or less, more preferably about 6 g/10 minutes or less. By setting the above MFR to 10 g/10 minutes or less, the viscosity difference with the intermediate layer can be suppressed, and stable film formation becomes possible.

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

The density of LLDPE is preferably about 0.9~0.94g / cm ^3, about 0.91~0.93g / cm ³ is more preferable.

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, if necessary. The antistatic agent that can be used in the surface layer can also be used in the surface layer. As the antistatic agent used in the surface layer, known surfactants such as anionic, cationic and nonionic surfactants can be selected, but especially from the standpoint of durability and durability, PEEA resin, hydrophilic PO resin and other nonionic surfactants can be selected. A system surfactant is suitable.

When the surface layer contains an antistatic agent, the content of the antistatic agent in the resin composition of the surface layer is preferably about 5 to 25% by weight, more preferably about 7 to 22% by weight. By blending the antistatic agent in the above range, the slipperiness of the surface layer when contacting with the expanding ring and uniformly expanding is not impaired.

In addition, since semiconductivity is effectively imparted, it is possible to quickly eliminate static electricity generated. For example, the dicing substrate film of the present invention containing an antistatic agent in the above range is preferable because the back surface has a surface resistivity of about 10 ⁷ to 10 ¹² Ω/□.

An antiblocking agent or the like may be further added to the surface layer. Addition of an anti-blocking agent is preferable because it prevents blocking when the dicing substrate film is wound into a roll. Examples of the anti-blocking agent include inorganic or organic fine particles.

(1-2) Back Layer Like the surface layer, the back layer is made of a resin composition containing a polyethylene resin.

A polyethylene resin used for the surface layer may be used, or a polyethylene resin different from the surface layer may be used.

Further, if necessary, like the surface layer, an antistatic agent or an antiblocking agent may be included.

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

When the front layer and/or the back layer is a multi-layer, it is expressed as surface layer-1, surface layer-2, surface layer-3,... in order from the outermost layer side, and back layer-1, back layer in order from the outermost layer side. Layer-2, back layer-3,...

(1-3) Intermediate Layer The intermediate layer is made of a resin composition containing a polyurethane resin (PU).

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

When the base film for dicing has an intermediate layer made of a resin composition containing a polyurethane-based resin (PU), expandability can be improved.

Since the base film for dicing has an intermediate layer made of a resin composition containing a polyurethane-based resin (PU), for example, when stealth dicing and then cutting (dividing) the semiconductor wafer and the die bond layer, low-temperature conditions and high-speed conditions are used. Even when the expansion is carried out in step 1, the dicing film stretches well.

(I) Polyurethane resin (PU)
A thermoplastic polyurethane resin (TPU) is preferably used as the polyurethane resin (PU). TPU is obtained by reacting a polyisocyanate, a polyol and a chain extender, from a soft segment made by the reaction of the polyol and the polyisocyanate and a hard segment made by the reaction of the chain extender and the polyisocyanate. Is a block copolymer.

Examples of the polyisocyanate include diphenylmethane diisocyanate, hexamethylene diisocyanate, tolidine diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate and xylylene diisocyanate. Of these, diphenylmethane diisocyanate and/or hexamethylene diisocyanate are preferable in terms of scratch resistance of the thermoplastic polyurethane resin.

Examples of the polyol include polytetramethylene ether glycol, polyester polyol, lactone polyester polyol, and the like. The polyester polyol is obtained by a polycondensation reaction of a dicarboxylic acid and a diol.

Specific examples of the diol used for producing the polyester polyol include ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and the like. Or a combination of these.

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

Among these polyols, the polytetramethylene ether glycol is preferable because the thermoplastic polyurethane resin can obtain high impact resilience. The number average molecular weight of the polyol is preferably 1,000 to 4,000, and particularly preferably 2,000 to 3,000.

Examples of chain extenders include ethanediol, 1,4-butanediol, 1,6-hexanediol, and other straight-chain aliphatic diols having 2 to 6 carbon atoms, 1,4-bis(hydroxyethoxy). Examples include benzene. Some amines such as hexamethylenediamine, isophoronediamine, tolylenediamine, monoethanolamine and the like can be used in combination. Of these, aliphatic linear diols having 2 to 6 carbon atoms are preferable in terms of scratch resistance of the thermoplastic polyurethane resin.

The density of the thermoplastic polyurethane resin is preferably about 1.1~1.5g / cm ^3, about 1.1~1.3g / cm ³ is more preferable.

The thermoplastic polyurethane resin can be produced from the above raw materials by a known method such as a one-shot method or a prepolymer method.

Examples of PU include Pandex manufactured by DIC Covestropolymer Co., Ltd., Miractolan manufactured by Nippon Miractolane Co., Ltd., and the like.

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

(Ii) Polyethylene resin
As the polyethylene-based resin, a resin that can be used in the surface layer can be used.

The same resin as the polyethylene-based resin used for the surface layer may be used for the intermediate layer, or a resin different from the polyethylene-based resin used for the surface layer may be used. As the polyethylene resin, it is preferable to use ethylene-methacrylic acid copolymer (EMAA) together with the above PU.

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

When the polyethylene resin is in the range of 0 to 80% by weight, the expandability of the dicing substrate film, that is, the tensile properties are good.

(1-4) Layer Structure of Base Film for Dicing The base film for dicing of the present invention includes a structure in which a surface layer/intermediate layer/back layer are laminated in this order.

The surface layer is the wafer contact side and is the layer in contact with the adhesive layer.

The intermediate layer may form a layer (single layer) of each resin alone, a layer (single layer) of a mixture of resins, or a layer (multilayer) of each resin. good.

In the dicing substrate film of the present invention, it is preferable that the surface layer and/or the back layer is a single layer or a multilayer. For the front and back layers, LDPE, EVA, etc. may form a layer (single layer) with each resin, a layer (single layer) with a mixture of resins, or a layer (multilayer) for each resin. May be formed.

The total thickness of the dicing substrate film of the present invention is preferably about 50 to 300 μm, more preferably about 70 to 200 μm, and further preferably about 80 to 150 μm. By setting the total thickness of the dicing substrate film to 50 μm or more, it becomes possible to protect the semiconductor wafer from impact when dicing the semiconductor wafer.

The ratio of the thickness of the front layer and the thickness of the back layer to the total thickness of the dicing substrate film is preferably about 4 to 80%, more preferably about 10 to 60%.

The ratio of the thickness of the intermediate layer to the total thickness of the dicing substrate film is preferably about 20 to 96%, more preferably about 40 to 90%.

As a specific example of the dicing substrate film, a case where the total thickness of the dicing substrate film is about 60 to 100 μm will be described.

The thickness of the front layer and the back layer is preferably about 2 to 44 μm, and more preferably about 10 to 38 μm. When the front layer and the back layer are multi-layers, each layer may be formed within the above thickness range as a total thickness.

The thickness of the intermediate layer is preferably about 12 to 96 μm, more preferably about 24 to 80 μm. When the intermediate layer is a multilayer, each layer may be formed within the above thickness range as a total thickness.

Example of 3 layers with 5 layers (surface layer-1/surface layer-2/intermediate layer/back layer-2/back layer-1)
In the example of 3 layers of 5 layers, as described above, the total thickness of the surface layer-1 and the surface layer-2 is in the range of the thickness of the surface layer, and similarly, the total thickness of the back layer-1 and the back layer-2. Is the range of the thickness of the back layer.

The surface layer-1 and the surface layer-2 may use the same type of polyethylene resin, or may use different types of polyethylene resin.

The back layer-1 and the back layer-2 may use the same type of polyethylene resin or different types of polyethylene resin.

When using the same type of polyethylene-based resin, for example, when using EVA, the EVA used in the surface layer-2 and the back layer-2 has a vinyl group content (compared to the EVA used in the surface layer-1 and the back layer-1 ( It is preferable to use EVA having a high VA content.

For the surface layer-1 and the back layer-1, it is preferable to use EVA having a VA content of about 5 to 15% by weight, and more preferably 7 to 13% by weight.

For the front layer-2 and the back layer-2, EVA having a VA content of about 15 to 33% by weight is preferably used, and more preferably 28 to 33% by weight of EVA is used.

From the viewpoint of MFR, it is preferable to use EVA having a higher melt flow rate (MFR) than EVA used for the surface layer-2 and the back layer-2.

In the front layer-1 and the back layer-1, the MFR at 190° C. of EVA is preferably about 0.1 g/10 minutes to 10 g/10 minutes, more preferably about 5 g/10 minutes to 10 g/10 minutes.

In the front layer-2 and the back layer-2, the MFR of EVA at 190° C. is preferably about 10 g/10 min to 40 g/10 min, more preferably about 12 g/10 min to 35 g/10 min.

(2) Manufacturing Method of Dicing Substrate Film The front layer/intermediate layer/back layer dicing substrate film can be produced by multi-layer coextrusion molding of the resin composition for the surface layer, the intermediate layer and the back layer. Specifically, the resin composition for the surface layer, the resin composition for the intermediate layer, and the resin composition for the back layer are coextruded so as to be laminated in the order of surface layer/intermediate layer/back layer. You can

Furthermore, when the surface layer and the back layer are formed into a multilayer structure, the resin composition for each surface layer and the back layer is put into each extruder, and, for example, surface layer-1/surface layer-2/intermediate layer/back layer It can be manufactured by coextrusion molding so that -2/back layer-1 is laminated in this order.

If necessary, an antistatic agent can be added to the resin composition forming the surface layer. The same applies to the back layer.

The above-mentioned resin for each layer is supplied to the screw type extruder in this order, extruded into a film form from a multilayer T die at 180 to 240°C, and cooled while passing through a cooling roll at 30 to 70°C to be substantially cooled. Is drawn without stretching. Alternatively, the resin for each layer may be once obtained as pellets and then extruded as described above.

The reason why the film is substantially unstretched at the time of take-up is to effectively expand the film after dicing. The term "substantially non-stretching" includes non-stretching or a slight stretching that does not adversely affect the expansion of the dicing film. In general, when pulling the film, it is sufficient to pull the film so as not to cause slack.

(3) Production of dicing film The dicing film of the present invention can be produced according to a well-known technique. For example, a pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is dissolved in a solvent such as an organic solvent, the solution is applied onto a dicing substrate film, and the solvent is removed to obtain a film having a substrate film/pressure-sensitive adhesive layer configuration. You can

The resin composition that constitutes the die bond layer is dissolved in a solvent such as an organic solvent, coated on another film (release film), and the solvent is removed to prepare a die bond film.

Further, the pressure-sensitive adhesive layer and the die-bonding layer are laminated so as to face each other, thereby producing a dicing film. As a result, a film having a structure of base film/adhesive layer/die bond layer can be obtained. At this stage, the die bond layer is bonded to the semiconductor wafer and the adhesive layer in a weakly (pseudo) bonded state.

After the expansion, the divided semiconductor chip and die bond layer are laminated with a predetermined package or semiconductor chip and heated to a temperature at which the die bond layer strongly adheres to each other.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(1) Raw Materials for Dicing Substrate Film Table 1 shows the raw materials for the dicing substrate film.

[Explanation of abbreviation]
PE-1-9: Polyethylene resin 1-9
SEBS: Styrene-butadiene copolymer hydrogenated product
(Styrene-ethylene-butylene-styrene copolymer)
TPU: Thermoplastic polyurethane (PU)
Amorphous PO: Amorphous polyolefin
LDPE: Branched low density polyethylene
EVA: Ethylene-vinyl acetate copolymer
VA content: vinyl acetate content
EMAA: Ethylene-methacrylic acid copolymer
MAA content: Methacrylic acid content
St content: Styrene content ratio (content of vinyl aromatic hydrocarbon (St) component in vinyl aromatic hydrocarbon resin)

(2) Production of surface layer/intermediate layer/back layer dicing base film A resin composition is blended with each component and composition so that the surface layer/intermediate layer/back layer (3 layers) described in Table 2 is obtained. A base film for dicing was produced.

The resin composition forming each layer is put into each extruder adjusted to 220° C., and extruded by a T die at 220° C. so as to be in the order of surface layer/intermediate layer/back layer, laminated, and dried at 30° C. It was coextruded on a chill roll in which cooling water circulates to obtain a flat three-layer film.

(3) Production of dicing substrate film of surface layer-1/surface layer-2/intermediate layer/back layer-2/back layer-1 Surface layer-1/surface layer-2/intermediate layer/back layer described in Tables 3 and 4 The resin composition was blended with each component and composition so as to be -2/back layer-1 (5 layers) to prepare a base film for dicing.

The resin composition forming each layer is put into each extruder adjusted to 220° C., and the order of surface layer-1/surface layer-2/intermediate layer/back layer-2/back layer-1 is 220 The film was extruded with a T-die of ℃, laminated, and coextruded on a chill roll in which cooling water of 30 ℃ circulated to obtain a flat 5-layer film.

(4) Evaluation of base film for dicing
(4-1) Low temperature expandability (Ex property)
<Evaluation method>
(Measurement of tensile elongation)
In the MD direction (extrusion direction of film forming) and TD direction (width direction of the film formed by film forming) of the film, processing was performed at a pulling speed of 200 mm/min so that the chuck distance was 40 mm in 10 mm width. The tensile elongation of the film was measured using the film sample.

(25% modulus measurement)
In the MD direction (extrusion direction of film forming) and TD direction (width direction of the film formed by film forming) of the film, processing was performed at a pulling speed of 200 mm/min so that the chuck distance was 40 mm in 10 mm width. An SS curve (stress-strain curve) was obtained using the film sample.

The stress values at the elongation rate of 25% of the obtained SS curves were read respectively.

<Evaluation criteria>
(A) Low temperature expandability (low temperature Ex property)
◯: The elongation is 100% or more when the tensile test is performed.
X: The film elongation is less than 100% when a tensile test is performed.

(B) Uniform expandability (uniform Ex property)
The modulus ratio (MD/TD) was obtained by calculating the ratio of the stress value at 25% elongation in MD direction and the stress value at 25% elongation in TD direction.
◯: Modulus ratio (MD/TD) is less than 1.5.
X: The modulus ratio (MD/TD) is 1.5 or more.

When the modulus ratio (MD/TD) is within the above range, the dicing substrate film exhibits good uniform expandability (uniform Ex property) under low temperature conditions of -15 to 5°C.

(4-2) Low temperature and high speed expandability (low temperature and high speed Ex property)
<Evaluation method>
(Measurement of elongation at break (maximum elongation) (%))
Tensile test: "HYDROSHOT HITS-T10" made by Shimadzu Corporation was processed under a -15±2°C environment at a pulling speed of 250 mm/sec so that the chuck-to-chuck distance was 10 mm at a width of 25 mm. The film sample was stretched in MD and TD until it broke.

An SS curve (stress-strain curve) was created from the load and elongation data plots, and the elongation at break (maximum elongation) was calculated.

<Evaluation criteria>
(High-speed tensile test evaluation (mechanical properties))
◯: Breaking tensile elongation in the MD and TD directions is 120% or more.
X: Breaking tensile elongation in the MD and TD directions is less than 120%.

In this evaluation method, the tensile speed is set to 250 mm/sec and a tensile test is conducted to evaluate the expandability under high-speed conditions in addition to low-temperature conditions. And, when the tensile elongation at break in MD and TD of the film is 120% or more, for example, after stealth dicing, when the film is expanded under low temperature conditions (-15 to 5°C) and high speed conditions, the film is good. Extend to.

(4-3) Heat shrinkability (HS property)
Condition 1-Tensile test: "Autograph AG-500NX TRAPEZIUM X" manufactured by Shimadzu Corporation was used, under a -15±2°C environment, at a pulling speed of 200 mm/min, a chuck distance of 40 mm at a width of 10 mm. The film sample processed so that it was stretched 200% in MD and TD, respectively.

Condition 2-Shrinkage test: The sample was heated for 5 seconds at a set temperature of 80° C. using “Humidifier TBP105DA” manufactured by Mitsubishi Heavy Industries Cold & Heat Co., Ltd.

<Evaluation method>
A film strip sample having a length of 100 mm (mark line interval 40 mm + gripping white (upper and lower 30 mm each)) and a width of 10 mm was prepared and stretched under the above condition 1.

After holding for 10 seconds in a state of being stretched by 200%, the chuck was returned to the original position, the chuck was opened, and the sample was contracted under the above condition 2.

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

Recovery rate [%]={(120-L)/80}×100
The recovery rate was measured in both MD and TD directions, and this was expressed as heat shrinkability (HS property).

<Evaluation criteria>
(A) Heat shrinkability (HS property)
○: Recovery rate is 70% or more due to heat shrink.
The recovery rate is more preferably 90 to 110%.
X: The recovery rate is less than 70% due to heat shrink.

When the recovery rate in the MD and TD directions is within the above range, the base film for dicing exhibits good heat shrinkability (HS property) under an environment of 80°C.

(A) Uniform heat shrinkability (uniform HS property)
◯: The ratio (MD/TD) of the MD recovery rate and the TD recovery rate is less than 1.2.
The recovery ratio (MD/TD) is more preferably 0.9 to 1.15.
X: The ratio of recovery rates (MD/TD) is 1.2 or more.

When the recovery ratio (MD/TD) is within the above range, the dicing substrate film exhibits good uniform heat shrinkability (uniform HS property) under the condition of 80°C.

In the dicing substrate films of the present invention (Examples 1 to 12), the dicing films were uniformly stretched even when expanded under low temperature conditions.

The dicing substrate film of the present invention (Example) had a significantly higher heat shrinkability (HS property) value than the comparative example. That is, the heat-shrinkability of the dicing substrate film of the present invention was better.

The low-temperature expandability (Ex property) was within the allowable range for both the dicing substrate films of the present invention (Example) and Comparative Example.

The dicing substrate film of the present invention (Example) had better low-temperature high-speed expanding property (low-temperature high-speed Ex property) than the comparative example.

(5) Consideration
Heat Shrinkability By using the dicing substrate film of the present invention, the dicing film (sheet) can shrink the slack portion by heating the generated slack portion even after passing through the expanding step and eliminate the slack. ..

When the dicing substrate film of the present invention is used, the dicing film (sheet) has a high restoration rate due to heat shrinkage.

By using the dicing substrate film of the present invention, the used dicing film can be collected in the rack more quickly and easily. That is, the dicing substrate film of the present invention has high heat-restoring property and the dicing film is uniformly recovered. That is, the heat shrinkability is excellently exhibited, and the rack recoverability is excellent. Further, products using the dicing substrate film of the present invention do not collide with each other and no defect occurs.

Expandability When the base film for dicing of the present invention is used, the expandability is good and the dicing film is uniformly stretched even when expanded under low temperature conditions. When the base film for dicing of the present invention is used, the semiconductor wafer and the die bond layer are satisfactorily cut (separated) together in the expansion performed under low temperature conditions.

When the substrate film for dicing of the present invention is used, particularly after stealth dicing, when the semiconductor wafer and the die bond layer are cut (divided), the expandability is improved even if the expansion is performed under low temperature conditions and high speed conditions. Is good, and the dicing film stretches well. When the base film for dicing of the present invention is used, the semiconductor wafer and the die bond layer are collectively cut (divided) favorably in the expansion performed under low temperature conditions and high speed conditions.

When the dicing substrate film of the present invention is used, miniaturization of semiconductor products progresses and the sheet is required to be more expandable (expandability), so that the sheet has higher expandability and shrinkability.

Claims (5)

A dicing substrate film comprising a structure in which a surface layer/intermediate layer/back layer is laminated in this order,
The front layer and the back layer are made of a resin composition containing a polyethylene resin,
The intermediate layer is made of a resin composition containing a polyurethane resin,
Base film for dicing. The dicing substrate film according to claim 1, wherein the surface layer and/or the back layer is a single layer or a multilayer. The polyethylene resin is branched low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene- At least one resin selected from the group consisting of ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMAA), and ionomer resin. The substrate film for dicing according to claim 1 or 2, which is The dicing substrate film according to claim 1, wherein the polyurethane resin is a thermoplastic polyurethane resin (TPU). A dicing film in which an adhesive layer and a die bond layer are provided in this order on the surface layer side of the dicing substrate film according to any one of claims 1 to 4.