Dicing substrate film

Abstract

To provide a base film for dicing that has high heat recovery properties and excellent rack recovery properties, and provide a base film for dicing that allows a dicing film to stretch uniformly even when expanding under a low temperature condition.SOLUTION: A base film for dicing includes a structure in which a surface layer, a middle layer and a back layer are laminated in this order, the surface layer and the back layer are made of a resin composition containing polyethylene resin, and the middle layer is made of a resin composition containing a polyurethane resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a dicing substrate film that is adhered to and fixed on a semiconductor wafer when dicing the semiconductor wafer into chips. [Background technology]

[0002] One method for manufacturing semiconductor chips is to first manufacture a large-area semiconductor wafer, then dice (cut and separate) the semiconductor wafer into chips, and finally pick up the diced chips. In recent years, stealth dicing has become known as a method for cutting semiconductor wafers, in which a laser processing device is used to cut (divide) the semiconductor wafer without touching it.

[0003] As a method for improving the cutting (separation) ability of semiconductor wafers by stealth dicing, a wafer processing tape is known in which the expansion is carried out under low-temperature conditions of -15 to 5°C, thereby suppressing the elongation of the die bond film provided on the dicing tape and increasing the stress, and which allows the semiconductor wafer and die bond film to be cut (separated) together well (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-185584 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-185591 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a dicing substrate film that has high heat recovery and excellent rack recovery properties.

[0006] Another object of the present invention is to provide a dicing substrate film that expands uniformly even when expanded under low-temperature conditions.

[0007] Another object of the present invention is to provide a dicing substrate film that stretches well even when expanding at low temperature (-15 to 5°C) and high speed conditions when cutting (dividing) a semiconductor wafer and a die bond layer after stealth dicing (laser dicing). [Means for solving the problem]

[0008] In semiconductor manufacturing lines, it is desirable to temporarily store sheets (dicing films including dicing substrate films) with unprocessed products remaining after the expanding process in racks. In this case, if slack remains in the sheets, they tend to be unable to be properly stored in the racks, or products may collide with each other, resulting in defects. The term "rack" is a name used in the industry, and is also known as a zipper or case.

[0009] To solve this problem, it is necessary to eliminate the sagging of the sheet after the expansion process. One method for doing this is the heat shrink technology (heat shrinkage restoration technology). This technology shrinks the sagging part that has occurred during the expansion process by heating it, and the sagging is eliminated. This is because the recovery rate due to heat shrinkage is high.

[0010] For example, even when expanding is performed under low-temperature conditions of -15 to 5°C, the dicing film is required to expand uniformly and to cut the semiconductor wafer well.

[0011] Furthermore, even when expanding is performed under high-speed conditions in addition to the low-temperature conditions after stealth dicing, it is required that the dicing film expands well and the semiconductor wafer and the die bond layer are cut (separated) well.

[0012] The present inventors have conducted extensive research to solve the above problems.

[0013] It has been discovered that by using a dicing base film with a structure in which the following top layer / middle layer / back layer are laminated in that order, and by using a polyurethane-based resin for the middle layer, sagging of the sheet (dicing film including the dicing base film) after the expansion process can be effectively eliminated by heat shrink technology (heat shrinkage restoration technology).

[0014] It was found that the dicing base film stretches uniformly even when expanded under low-temperature conditions, and that the dicing base film stretches well even when expanded under high-speed conditions in addition to low-temperature conditions.

[0015] Section 1. A dicing substrate film including a structure in which a surface layer / an intermediate layer / a back layer are laminated in this order, The front and back layers are made of a resin composition containing a polyethylene resin, The intermediate layer is made of a resin composition containing a polyurethane-based resin. Dicing substrate film.

[0016] Section 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 multiple layers.

[0017] Section 3. 3. The dicing substrate film according to item 1 or 2, wherein the polyethylene resin is at least one resin selected from the group consisting of 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 ionomer resin.

[0018] Section 4. 4. The dicing base film according to any one of items 1 to 3, wherein the polyurethane resin is a thermoplastic polyurethane resin (TPU).

[0019] Section 5. 5. A dicing film comprising a dicing base film according to any one of items 1 to 4, and an adhesive layer and a die-bonding layer provided in this order on the surface layer side of the dicing base film.

[0020] Section 6. A dicing substrate film used in the production of a stealth dicing film, The stealth dicing film is used when performing expansion under low-temperature conditions of -15 to 5°C, The dicing substrate film includes a structure in which a surface layer / an intermediate layer / a back layer are laminated in this order, the surface layer and the back layer are made of a resin composition containing a polyethylene-based resin, the intermediate layer is made of a resin composition containing a thermoplastic polyurethane resin (TPU), In the stealth dicing film, an adhesive layer and a die bond layer are provided in this order on the surface side of the dicing base film, The intermediate layer is made of a resin composition containing 0 to 50% by weight of a polyethylene resin and the remainder being a thermoplastic polyurethane resin (TPU). Dicing substrate film. [Effects of the Invention]

[0021] The dicing base film of the present invention allows for quicker and easier recovery of used dicing films onto racks. In other words, the dicing base film of the present invention has high thermal recovery, i.e., good heat shrinkability, and is excellent in rack recovery.

[0022] When the dicing substrate film of the present invention is used, the dicing film expands uniformly even when expanding is carried out under low temperature conditions.

[0023] When the dicing substrate film of the present invention is used, for example, when cutting (dividing) the semiconductor wafer and the die bond layer after stealth dicing, the dicing film stretches well even when expanding is performed under low-temperature and high-speed conditions. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention relates to a substrate film for dicing.

[0025] The present invention further relates to a dicing film comprising a dicing substrate film on which an adhesive layer and a die bond layer are provided in this order.

[0026] (1) Dicing substrate film The dicing substrate film of the present invention is It is characterized by having a structure in which a surface layer, an intermediate layer, and a back layer are laminated in this order.

[0027] The surface layer and / or the back layer is preferably a single layer or multiple layers.

[0028] Each layer constituting the dicing substrate film of the present invention will be described in detail below.

[0029] (1-1) Surface layer The surface layer is made of a resin composition containing a polyethylene-based resin.

[0030] The polyethylene resin contained in the surface layer is preferably at least one component selected from the group consisting of 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 ionomer resin.

[0031] When the surface layer is made of a 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.

[0032] In addition, polypropylene resins may be blended as long as the effects of the present invention are not impaired.

[0033] The melt flow rate (MFR) of the ethylene-vinyl acetate copolymer (EVA) at 190°C is preferably about 30 g / 10 min or less, more preferably about 20 g / 10 min or less, more preferably about 15 g / 10 min or less, and even more preferably about 10 g / 10 min or less. By setting the MFR to 10 g / 10 min or less, the difference in viscosity with the intermediate layer can be suppressed, enabling stable film formation.

[0034] Furthermore, the MFR of the 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.

[0035] The density of EVA is 0.9 to 0.96 g / cm 3 The preferred range is 0.92 to 0.94 g / cm 3 A degree is more preferable.

[0036] The melt flow rate (MFR) of branched low-density polyethylene (LDPE) at 190°C is preferably about 10 g / 10 min or less, more preferably about 6 g / 10 min or less. By setting the MFR to 10 g / 10 min or less, the difference in viscosity with the intermediate layer can be suppressed, enabling stable film formation.

[0037] Furthermore, in order to facilitate extrusion of the resin, the MFR of the LDPE is preferably about 0.1 g / 10 min or more, and more preferably about 0.3 g / 10 min or more.

[0038] The density of LDPE is 0.9 to 0.94 g / cm 3 The preferred range is 0.91 to 0.93 g / cm 3 A degree is more preferable.

[0039] The melt flow rate (MFR) of linear low-density polyethylene (LLDPE) at 190°C is preferably about 10 g / 10 min or less, more preferably about 6 g / 10 min or less. By setting the MFR at 10 g / 10 min or less, the difference in viscosity with the intermediate layer can be suppressed, enabling stable film formation.

[0040] Furthermore, in order to facilitate extrusion of the resin, the MFR of the LLDPE is preferably about 0.1 g / 10 min or more, and more preferably about 0.3 g / 10 min or more.

[0041] The density of LLDPE is 0.9 to 0.94 g / cm 3 The preferred range is 0.91 to 0.93 g / cm 3 A degree is more preferable.

[0042] Here, the melt flow rate (MFR) was determined in accordance with ISO 1133, and the density was determined in accordance with ISO 1183-1:2004.

[0043] The surface layer may further contain an antistatic agent as needed. The antistatic agents that can be used in the surface layer described above 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. However, from the viewpoints of sustainability and durability, nonionic surfactants such as PEEA resin and hydrophilic PO resin are particularly preferred.

[0044] 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 wt %, more preferably about 7 to 22 wt %. By blending the antistatic agent in this range, the slipperiness of the surface layer is not impaired when it comes into contact with the expanding ring and is uniformly expanded.

[0045] In addition, since semiconductivity is effectively imparted, it becomes possible to quickly remove static electricity that is generated. For example, the dicing substrate film of the present invention containing the antistatic agent in the above range has a surface resistivity of 10 7 ~10 12 This is preferable because it is about Ω / □.

[0046] An antiblocking agent or the like may be further added to the surface layer. Addition of an antiblocking agent is preferable because it suppresses blocking when the dicing substrate film is wound into a roll. Examples of the antiblocking agent include inorganic or organic fine particles.

[0047] (1-2) Lining The back layer, like the surface layer, is made of a resin composition containing a polyethylene-based resin.

[0048] The polyethylene resin used for the surface layer may be used, or a polyethylene resin different from that for the surface layer may be used.

[0049] If necessary, the layer may contain an antistatic agent or an antiblocking agent, similar to the surface layer.

[0050] In the dicing base film of the present invention, the surface layer and / or the back layer may be a single layer or multiple layers. The dicing base film of the present invention can be provided with multiple surface layers and / or multiple back layers as needed.

[0051] When the surface layer and / or back layer is a multi-layer structure, they are represented as surface layer-1, surface layer-2, surface layer-3, etc. from the outermost surface side, and as back layer-1, back layer-2, back layer-3, etc. from the innermost surface side.

[0052] (1-3) Middle class The intermediate layer is made of a resin composition containing a polyurethane resin (PU).

[0053] The PU is preferably a thermoplastic polyurethane resin (TPU).

[0054] The dicing substrate film has an intermediate layer made of a resin composition containing a polyurethane resin (PU), which can improve the expandability.

[0055] Because the dicing base film has an intermediate layer made of a resin composition containing a polyurethane resin (PU), the dicing film stretches well even when expanding under low-temperature and high-speed conditions, for example, when cutting (separating) the semiconductor wafer and the die-bonding layer after stealth dicing.

[0056] (i) Polyurethane resin (PU) As the polyurethane resin (PU), it is preferable to use a thermoplastic polyurethane resin (TPU). TPU is obtained by reacting a polyisocyanate, a polyol, and a chain extender, and is a block copolymer consisting of a soft segment formed by the reaction of the polyol with the polyisocyanate and a hard segment formed by the reaction of the chain extender with the polyisocyanate.

[0057] Examples of polyisocyanates include diphenylmethane diisocyanate, hexamethylene diisocyanate, tolidine diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, etc. Among these, diphenylmethane diisocyanate and / or hexamethylene diisocyanate are preferred in terms of the abrasion resistance of the thermoplastic polyurethane resin.

[0058] Examples of polyols include polytetramethylene ether glycol, polyester polyols, lactone-based polyester polyols, etc. Polyester polyols are obtained by polycondensation reaction of dicarboxylic acids and diols.

[0059] Specific examples of diols used in the production of polyester polyols include ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol, which may be used alone or in combination.

[0060] The dicarboxylic acids used in the present invention include adipic acid, sebacic acid, etc., which may be used alone or in combination.

[0061] Among these polyols, polytetramethylene ether glycol is preferred because it allows the thermoplastic polyurethane resin to have high impact resilience. The number average molecular weight of such polyol is preferably 1,000 to 4,000, and particularly preferably 2,000 to 3,000.

[0062] Examples of chain extenders include aliphatic linear diols having 2 to 6 carbon atoms, such as ethanediol, 1,4-butanediol, and 1,6-hexanediol, and 1,4-bis(hydroxyethoxy)benzene. Amines such as hexamethylenediamine, isophoronediamine, tolylenediamine, and monoethanolamine can also be used in combination. Of these, aliphatic linear diols having 2 to 6 carbon atoms are preferred in terms of the abrasion resistance of the thermoplastic polyurethane resin.

[0063] The density of thermoplastic polyurethane resin is 1.1 to 1.5 g / cm 3 The preferred range is 1.1 to 1.3 g / cm 3 A degree is more preferable.

[0064] 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.

[0065] Examples of PU include Pandex manufactured by DIC Covestro Polymer Co., Ltd. and Miractoran manufactured by Nippon Miractoran Co., Ltd.

[0066] The resin composition constituting the intermediate layer may contain (ii) a polyethylene resin in addition to the (i) PU.

[0067] (ii) Polyethylene resin The polyethylene resin may be any resin that can be used for the surface layer.

[0068] The intermediate layer may be made of the same polyethylene resin as that used in the surface layer, or a different resin may be used. As the polyethylene resin, it is preferable to use ethylene-methacrylic acid copolymer (EMAA) together with the above-mentioned PU.

[0069] When the intermediate layer contains a polyethylene resin, the content is preferably 0 to 80% by weight, more preferably 0 to 70% by weight.

[0070] If the polyethylene resin is in the range of 0 to 80% by weight, the expandability of the dicing base film, that is, the tensile properties, are good.

[0071] (1-4) Layer structure of dicing substrate film The dicing substrate film of the present invention has a structure in which a surface layer / an intermediate layer / a back layer are laminated in this order.

[0072] The surface layer is the wafer contact side and is the layer in contact with the adhesive layer.

[0073] The intermediate layer may be formed as a layer (single layer) using each resin alone, a layer (single layer) using a mixture of resins, or a layer (multilayer) using each resin individually.

[0074] In the dicing substrate film of the present invention, the front and / or back layers are preferably single or multi-layered. The front and back layers may be formed of a single layer of LDPE, EVA, or other resin, a single layer of a resin mixture, or a single layer of each resin.

[0075] 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 even more 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.

[0076] The ratio of the thickness of the front layer and the back layer to the total thickness of the dicing substrate film is preferably about 4 to 80%, more preferably about 10 to 60%.

[0077] The ratio of the thickness of the intermediate layer to the total thickness of the dicing substrate film is preferably about 20 to 96%, and more preferably about 40 to 90%.

[0078] As a specific example of the dicing base film, a dicing base film having a total thickness of about 60 to 100 μm will be described.

[0079] The thickness of each of the surface layer and the back layer is preferably about 2 to 44 μm, more preferably about 10 to 38 μm. When the surface layer and the back layer are multiple layers, each layer may be formed within the above thickness range as the total thickness.

[0080] 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 multi-layered layer, each layer may be formed so that the total thickness falls within the above thickness range.

[0081] Example of 3 types, 5 layers (surface layer-1 / surface layer-2 / intermediate layer / back layer-2 / back layer-1) In the example of three types and five layers, as described above, the total thickness of surface layer-1 and surface layer-2 falls within the range of the thickness of the surface layers, and similarly, the total thickness of back layer-1 and back layer-2 falls within the range of the thickness of the back layers.

[0082] The surface layer-1 and the surface layer-2 may be made of the same type of polyethylene resin or different types of polyethylene resins.

[0083] The back layer-1 and back layer-2 may be made of the same type of polyethylene resin, or different types of polyethylene resins.

[0084] When using the same type of polyethylene resin, for example, when using EVA, it is preferable that the EVA used for the surface layer-2 and the back layer-2 has a higher vinyl group content (VA content) than the EVA used for the surface layer-1 and the back layer-1.

[0085] In the surface layer-1 and the back layer-1, EVA having a VA content of about 5 to 15% by weight is preferably used, and EVA having a VA content of about 7 to 13% by weight is more preferably used.

[0086] In the surface layer-2 and the back layer-2, EVA having a VA content of about 15 to 33% by weight is preferably used, and EVA having a VA content of about 28 to 33% by weight is more preferably used.

[0087] In terms of MFR, it is preferable that the EVA used for the surface layer-2 and back layer-2 has a higher melt flow rate (MFR) than the surface layer-1 and back layer-1.

[0088] In the surface layer-1 and the back layer-1, the MFR of the EVA at 190°C is preferably about 0.1 g / 10 min to 10 g / 10 min, more preferably about 5 g / 10 min to 10 g / 10 min.

[0089] In the surface layer-2 and the back layer-2, the MFR of the 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.

[0090] (2) Manufacturing method of dicing substrate film The surface layer / intermediate layer / rear layer dicing substrate film can be produced by multilayer co-extrusion molding of resin compositions for the surface layer, intermediate layer, and rear layer. Specifically, the surface layer resin composition, intermediate layer resin composition, and rear layer resin composition can be co-extrusion molded so that they are laminated in this order: surface layer / intermediate layer / rear layer.

[0091] Furthermore, when the surface layer and the back layer are made into a multi-layer structure, the resin compositions for each surface layer and back layer can be fed into respective extruders and co-extruded so that the layers are laminated in the order of, for example, surface layer-1 / surface layer-2 / intermediate layer / back layer-2 / back layer-1.

[0092] If necessary, an antistatic agent may be added to the resin composition constituting the surface layer. The same applies to the back layer.

[0093] The resins for each layer are fed to a screw extruder in the stated order, extruded through a multilayer T-die at 180 to 240°C into a film, and cooled by passing through cooling rolls at 30 to 70°C, and taken up without being stretched substantially. Alternatively, the resins for each layer may be obtained as pellets and then extruded as described above.

[0094] The reason for not stretching the film substantially during take-up is to effectively expand the film after dicing. This "substantially not stretching" includes no stretching or slight stretching that does not adversely affect the expansion of the dicing film. Usually, the film should be pulled to a degree that does not cause sagging during take-up.

[0095] (3) Dicing film manufacturing The dicing film of the present invention can be produced according to well-known techniques. For example, the adhesive constituting the adhesive layer is dissolved in a solvent such as an organic solvent, and the solution is applied to a dicing base film, followed by removing the solvent to obtain a film having a base film / adhesive layer configuration.

[0096] The resin composition that constitutes the die bond layer is dissolved in a solvent such as an organic solvent, and the solution is applied onto another film (release film), and the solvent is removed to produce a die bond film.

[0097] Furthermore, the adhesive layer and the die bond layer are stacked facing each other to produce a dicing film. This results in a film having a base film / adhesive layer / die bond layer configuration. At this stage, the die bond layer is bonded to the semiconductor wafer in a weak (pseudo) adhesive state.

[0098] After expanding, the cut semiconductor chips and die bond layers are stacked on a predetermined package or semiconductor chip, and heated to a temperature at which the die bond layer is strongly bonded, thereby bonding them together. [Example]

[0099] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0100] (1) Raw material for dicing substrate film Table 1 shows the raw materials for the dicing substrate film.

[0101] [Table 1]

[0102] [Explanation of abbreviations] PE-1 to 9: Polyethylene resins 1 to 9 SEBS: Hydrogenated styrene-butadiene copolymer (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 Styrene content: Styrene content (Vinyl aromatic hydrocarbon (St) component content in vinyl aromatic hydrocarbon resin)

[0103] (2) Manufacturing of surface / intermediate / back layer dicing substrate films Resin compositions were blended with the components and compositions shown in Table 2 to form a surface layer / intermediate layer / back layer (three layers), to prepare a substrate film for dicing.

[0104] The resin compositions constituting each layer were fed into respective extruders adjusted to 220°C, extruded through a T-die at 220°C in the order of surface layer / middle layer / back layer, laminated, and co-extruded onto a chill roll through which 30°C cooling water was circulated to obtain a flat three-layer film.

[0105] [Table 2]

[0106] (3) Manufacturing of dicing substrate film of surface layer-1 / surface layer-2 / intermediate layer / back layer-2 / back layer-1 A resin composition was blended with each component and composition to form the top layer-1 / top layer-2 / intermediate layer / bottom layer-2 / bottom layer-1 (5 layers) shown in Tables 3 and 4, to prepare a dicing substrate film.

[0107] The resin compositions constituting each layer were fed into respective extruders adjusted to 220°C, extruded through a T-die at 220°C in the order of surface layer-1 / surface layer-2 / intermediate layer / back layer-2 / back layer-1, laminated, and co-extruded onto a chill roll through which 30°C cooling water was circulated to obtain a flat five-layer film.

[0108] [Table 3]

[0109] [Table 4]

[0110] (4) Evaluation of dicing substrate film (4-1) Low-temperature expandability (Ex property) <Evaluation method> (Measurement of tensile elongation) The tensile elongation of the film was measured in the MD direction (extrusion direction of the film) and TD direction (width direction of the film formed by film forming) of the film at a pulling speed of 200 mm / min using a film sample processed to a width of 10 mm with a chuck distance of 40 mm.

[0111] (25% modulus measurement) The SS curve (stress-strain curve) was obtained using a film sample processed to a width of 10 mm with a chuck distance of 40 mm at a tension speed of 200 mm / min in the MD direction (extrusion direction of film molding) and TD direction (width direction of the film molded by film molding).

[0112] The stress values ​​at an elongation rate of 25% were read from the obtained SS curves.

[0113] <Evaluation criteria> (A) Low-temperature expandability (low-temperature Ex) ○: When a tensile test was carried out, the elongation rate was 100% or more. ×: When the tensile test was carried out, the film elongation was less than 100%.

[0114] (a) Uniform expandability (uniform Ex) The ratio of the stress value at an elongation rate of 25% in the MD direction to the stress value at an elongation rate of 25% in the TD direction was calculated and used 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.

[0115] When the modulus ratio (MD / TD) is within the above range, the dicing substrate film exhibits good uniform expandability (uniform Ex) under low temperature conditions of -15 to 5°C.

[0116] (4-2) Low-temperature, high-speed expansion property (low-temperature, high-speed Ex property) <Evaluation method> (Measurement of breaking elongation (maximum elongation) (%)) Tensile test: Using Shimadzu Corporation's "HYDROSHOT·HITS-T10," a film sample processed to a width of 25 mm with a chuck distance of 10 mm was stretched in both the MD and TD directions at a tension speed of 250 mm / sec in an environment of -15±2°C until it broke.

[0117] An SS curve (stress-strain curve) was created from the data plot of load and elongation, and the breaking elongation (maximum elongation) was calculated.

[0118] <Evaluation criteria> (High-speed tensile test evaluation (mechanical properties)) ◯: The tensile elongation at break in both the MD and TD directions is 120% or more. ×: The tensile elongation at break in the MD and TD directions is less than 120%.

[0119] In this evaluation method, the tensile test is performed at a tensile speed of 250 mm / sec to evaluate the expandability under high-speed conditions in addition to low-temperature conditions. If the tensile elongation at break in the MD and TD directions of the film is 120% or more, the film will stretch well when expanding under low-temperature conditions (-15 to 5°C) and high-speed conditions, for example, after stealth dicing.

[0120] (4-3) Heat shrink property (HS property) Condition 1 - Tensile test: Using Shimadzu Corporation's Autograph AG-500NX TRAPEZIUM X, a film sample processed to a width of 10 mm and a chuck distance of 40 mm was stretched 200% in both the MD and TD directions at a tension speed of 200 mm / min in an environment of -15±2°C.

[0121] Condition 2 - Shrinkage test: Using a "humidistat TBP105DA" manufactured by Mitsubishi Heavy Industries Refrigeration & Refrigeration Co., Ltd., the sample was heated at a set temperature of 80°C for 5 seconds.

[0122] <Evaluation method> A film strip sample measuring 100 mm in length (40 mm between gauge lines + 30 mm each for gripping) and 10 mm in width was prepared and stretched under the above condition 1.

[0123] After maintaining the 200% elongated state for 10 seconds, the chuck was returned to its original position, released, and the sample was contracted under Condition 2 above.

[0124] The distance between the gauge lines L [mm] after shrinkage was measured, and the recovery rate was calculated using the following formula.

[0125] Recovery rate [%]={(120-L) / 80}×100 The recovery rate was measured in both the MD and TD directions, and this was expressed as heat shrink property (HS property).

[0126] <Evaluation criteria> (A) Heat shrink property (HS property) ○: Recovery rate is 70% or more by heat shrinking. The recovery rate is more preferably 90 to 110%. ×: Recovery rate due to heat shrinking is less than 70%.

[0127] When the recovery rates in the MD and TD directions are within the above ranges, the dicing substrate film exhibits good heat shrink properties (HS properties) in an 80°C environment.

[0128] (a) Uniform heat shrinkability (uniform HS property) ◯: 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 recovery ratio (MD / TD) is more preferably 0.9 to 1.15. ×: The recovery rate ratio (MD / TD) is 1.2 or more.

[0129] When the recovery rate ratio (MD / TD) is in the above range, the dicing substrate film exhibits good uniform heat shrink properties (uniform HS properties) under conditions of 80°C.

[0130] [Table 5]

[0131] [Table 6]

[0132] The dicing base films of the present invention (Examples 1 to 12) expanded uniformly even when expanded under low temperature conditions.

[0133] [Table 7]

[0134] The dicing substrate film of the present invention (Example) had a significantly higher heat shrink property (HS property) value than the comparative example, meaning that the dicing substrate film of the present invention had better heat shrink property.

[0135] The low-temperature expandability (Ex property) was within an acceptable range for both the dicing substrate films of the present invention (Example) and the comparative example.

[0136] The dicing substrate film of the present invention (Example) had better low-temperature, high-speed expandability (low-temperature, high-speed Ex property) than the comparative example.

[0137] (5) Discussion Heat shrinkability When the dicing base film of the present invention is used, the dicing film (sheet) can be heated to shrink any sagging portions that have occurred even after the expanding step, thereby eliminating the sagging.

[0138] When the dicing substrate film of the present invention is used, the dicing film (sheet) in particular has a high restoration rate due to heat shrinkage.

[0139] By using the dicing base film of the present invention, used dicing film can be collected into a rack more quickly and easily. In other words, the dicing base film of the present invention has high heat recovery and uniform recovery. In other words, it exhibits good heat shrinkability and is excellent in rack recovery. Furthermore, products using the dicing base film of the present invention do not collide with each other, resulting in no defects.

[0140] Expandability When the dicing base film of the present invention is used, the expandability is good and the dicing film expands uniformly even when expanding is performed under low-temperature conditions. When the dicing base film of the present invention is used, the semiconductor wafer and the die-bonding layer are cut (divided) together well during expanding performed under low-temperature conditions.

[0141] When the dicing base film of the present invention is used, particularly when cutting (dividing) the semiconductor wafer and the die bond layer after stealth dicing, the expandability is good and the dicing film stretches well even when expanding is performed under low-temperature and high-speed conditions. When the dicing base film of the present invention is used, the semiconductor wafer and the die bond layer are cut (divided) together well in expanding performed under low-temperature and high-speed conditions.

[0142] The use of the dicing substrate film of the present invention results in a sheet with higher expandability and shrinkability, in keeping with the trend toward smaller semiconductor products and the need for sheets with greater expandability.

Claims

1. A dicing base film used in the manufacture of a stealth dicing film, comprising: The stealth dicing film is used when performing expansion under low temperature conditions of -15 to 5°C, The dicing base film includes a structure in which a surface layer, an intermediate layer, and a back layer are 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 polyethylene resin and a thermoplastic polyurethane resin (TPU), In the stealth dicing film, a pressure-sensitive adhesive layer and a die bond layer are provided in this order on the surface side of the dicing base film, The intermediate layer is made of a resin composition containing more than 0% by weight and not more than 50% by weight of a polyethylene resin and the remainder being a thermoplastic polyurethane resin (TPU). Substrate film for dicing.

2. A dicing substrate film used in the manufacture of a stealth dicing film, comprising: The stealth dicing film is used when performing expansion under low temperature conditions of -15 to 5°C, The dicing base film includes a structure in which a surface layer, an intermediate layer, and a back layer are 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 thermoplastic polyurethane resin (TPU), In the stealth dicing film, a pressure-sensitive adhesive layer and a die bond layer are provided in this order on the surface side of the dicing base film, the intermediate layer is made of a resin composition containing 0 to 50% by weight of a polyethylene resin and the remainder being a thermoplastic polyurethane resin (TPU); The ratio of the thickness of the intermediate layer to the total thickness of the dicing base film is 20% or more and 30 / 90 or less. Substrate film for dicing.

3. A dicing substrate film used in the manufacture of a stealth dicing film, comprising: The stealth dicing film is used when performing expansion under low temperature conditions of -15 to 5°C, The dicing base film includes a structure in which a surface layer, an intermediate layer, and a back layer are 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 thermoplastic polyurethane resin (TPU), In the stealth dicing film, a pressure-sensitive adhesive layer and a die bond layer are provided in this order on the surface side of the dicing base film, the intermediate layer is made of a resin composition containing 0 to 50% by weight of a polyethylene resin and the remainder being a thermoplastic polyurethane resin (TPU); The tensile test is performed at a tensile speed of 250 mm / sec, a chuck distance of 10 mm, a sample width of 25 mm, and an environmental temperature of -15±2°C. The tensile elongation at break in the MD and TD directions is 120% or more. A tensile test was conducted at a tensile speed of 200 mm / min, a chuck distance of 40 mm, a sample width of 10 mm, and an environmental temperature of -15±2°C. A sample with a length of 100 mm was stretched 200% and held in that state for 10 seconds, and then the sample was heated at 80°C for 5 seconds. In this test, the recovery rate in both the MD and TD directions was 70% or more. Substrate film for dicing.

4. In a tensile test with a tensile speed of 200 mm / min, a chuck distance of 40 mm, and a sample width of 10 mm, the elongation in the MD and TD directions is 100% or more, and the 25% modulus ratio (MD / TD) is less than 1.

5.

4. The dicing substrate film according to claim 3, wherein a ratio of recovery rate in MD to recovery rate in TD (MD / TD) is less than 1.2 when a shrinkage test is conducted in which a sample having a length of 100 mm is elongated by 200% and held in that state for 10 seconds in a tensile test with a tensile speed of 200 mm / min, a chuck distance of 40 mm, a sample width of 10 mm, and an environmental temperature of -15±2°C, and then the sample is heated at 80°C for 5 seconds.

5. 5. The dicing substrate film according to claim 1, wherein the front layer and / or the back layer is a single layer or multiple layers.

6. 6. The dicing substrate film according to claim 1, wherein the polyethylene resin is at least one resin selected from the group consisting of 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 ionomer resin.

7. The intermediate layer is made of a resin composition containing 25% by weight or more and 50% by weight or less of a polyethylene resin and the remainder being a thermoplastic polyurethane resin (TPU), 7. The dicing substrate film according to claim 1.

8. A dicing film comprising the dicing base film according to any one of claims 1 to 7, and an adhesive layer and a die-bonding layer provided in this order on the surface side of the dicing base film.

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