JP7311312B2 - Base film for dicing sheet - Google Patents

Description

The present invention relates to a base film for a dicing sheet, which is used for fixing a semiconductor wafer when the semiconductor wafer is diced into chips.

As a method for manufacturing semiconductor chips, a cylindrical single-crystal silicon ingot is sliced with a wire saw or the like, etched and polished, and then the manufactured semiconductor wafers with a diameter of about 12 inches and 8 inches are diced into chips. ) and how the diced chips are transferred to the expanding process and picked up.

A dicing sheet is used to fix the semiconductor wafer in the semiconductor wafer dicing process.

A dicing sheet consists of an adhesive layer for fixing the semiconductor wafer and a resin layer as a support for supporting it. A base film for the dicing sheet is used as the resin layer. After manufacturing the sheet base film, the adhesive layer is processed in a post-process, wound into a roll, stored and transported as a dicing sheet, and unrolled from the roll by a dicing maker for use.

In the dicing process in the manufacture of semiconductor chips, the pressure-sensitive adhesive layer and the base film for a dicing sheet, which is a support, are partly cut (generally referred to as half-cutting) together with the semiconductor wafer. At that time, cutting waste derived from the base film for the dicing sheet (also referred to as thread-like or whisker-like waste, burrs, and whiskers generated from the film after dicing) is generated by the heat due to the impact and friction of the dicing blade. This debris can contaminate the wafer and cause a decrease in chip yield.

Considering that this cutting waste causes malfunction of devices such as sensors when picking up the semiconductor chip and causes a decrease in productivity, it is required that the cutting waste be as small as possible.

Furthermore, the dicing sheet is usually rolled into a roll for production, storage, transportation, and the like. Therefore, if blocking occurs between the films, the quality will be deteriorated. In other words, even if the dicing sheet has excellent quality, problems due to such blocking may occur.

Therefore, the following dicing sheets have been reported with the main purpose of eliminating various problems in the dicing process, the pick-up process, and the storage and transportation of roll-shaped materials.

Patent Literature 1 proposes a dicing base film and a dicing film made of a polypropylene resin and an olefin thermoplastic elastomer as a technique for reducing shavings during the dicing process.

Patent Document 2 proposes a dicing substrate film provided with a layer containing a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene hydrocarbon and a polypropylene-based resin as a technique for reducing cutting debris during the dicing process. there is

In Patent Document 3, in a substrate film for dicing having a multilayer structure, a resin composed of 30 to 80% by weight of a styrene-butadiene copolymer (SEBS) and 20 to 70% by weight of a polypropylene resin (PP) is used as the first layer. A composition comprising 100 parts by weight of a composition and 10 to 100 parts by weight of a thermoplastic olefinic elastomer (TPO), a thermoplastic resin having rubber elasticity as a second layer, and a laminate of the first layer and the second layer 2 A substrate film for layer dicing is described.

In Patent Document 4, in a base film consisting of at least two layers, polypropylene is used as a resin for the layer on the adhesive layer side, and hydrogenated styrene-butadiene copolymer is used for layers other than the resin layer on the adhesive layer side. It is stated to use

JP 2011-23575 A JP-A-2011-23632 Japanese Patent No. 5068070 JP-A-2005-174963

However, in the base film for a dicing sheet described in Patent Document 1, the flexibility of the dicing sheet itself is impaired by the polypropylene-based resin, which is the main component, and the tensile elastic modulus becomes too high, and sufficient expandability cannot be obtained, resulting in breakage. I have an easy problem.

In addition, the base films for dicing sheets described in Patent Documents 2 and 3 have the problem that blocking occurs on both sides of the base material, degrading processability such as subsequent pressure-sensitive adhesive processing.

Moreover, in the base film for a dicing sheet described in Patent Document 4, there is a problem that a sufficient effect of reducing shavings cannot be obtained with polypropylene.

An object of the present invention is to provide a base film for a dicing sheet that suppresses the generation of shavings in the dicing process of a semiconductor wafer and has excellent breaking strength and anti-blocking properties.

The above objects of the present invention have been basically achieved by the following inventions.

A laminated film having at least an A layer, a B layer, and a C layer, wherein the A layer has a ten-point average roughness Rz of 1.5 to 15.0 μm, and the B layer contains low-density polyethylene, the low-density polyethylene is 50% to 100% by weight, and the layer C is made of an olefinic thermoplastic elastomer.

Since the base film for a dicing sheet of the present invention hardly generates shavings in the dicing process, there is no concern about contamination of silicon chips after the dicing process, and the ten-point average roughness Rz of the surface of the A layer is within a specific range. As a result, blocking over time does not occur even when stored in a roll.

The base film for a dicing sheet of the present invention is a laminated film having a multi-layer lamination form of at least A layer, B layer and C layer. The A layer has a ten-point average roughness Rz of 1.5 to 15.0 μm, the B layer contains low-density polyethylene, the content of the low-density polyethylene is 50% to 100% by weight, and the C layer consists of an olefinic thermoplastic elastomer. The base film for a dicing sheet of the present invention preferably comprises layers A, B and C in this order. A layer having another function may be provided between each layer. Moreover, it is preferable that the A layer is the outermost layer. With such a layer structure, a base film for a dicing sheet having an extremely excellent total balance can be obtained. That is, it is possible to suppress the generation of shavings in the dicing process, eliminate blocking over time even when stored in a roll form, and eliminate the problem of breakage of the laminated film in the expanding process after the dicing process. Moreover, since there is little friction with the dicing stage, good expandability can be obtained.

The method for producing the base film for a dicing sheet of the present invention is not particularly limited. Lamination, a method of laminating another layer by a known lamination method such as extrusion coating, a method of forming each layer independently into a film, and then laminating each of the obtained films by dry lamination, and the like. From the viewpoint of productivity, a coextrusion molding method in which the materials for the layers A, B, and C are fed to a multi-layer extruder and molded is preferable, and from the viewpoint of thickness accuracy, a T-die molding method is more preferable.

In the case of co-extrusion molding, the constituent components of the layers A, B and C are extruded from a melt extruder. At this time, the upper limit of the resin extrusion temperature is preferably 240°C, more preferably 230°C, and still more preferably 220°C. If the extrusion temperature of the resin exceeds 240° C., thermal deterioration of the resin may occur, and gel may easily occur. Although there is no particular lower limit for the extrusion temperature of the resin, if the resin temperature is less than 180° C., the melt viscosity becomes too high, which may reduce the productivity.

Details of each layer constituting the base film for a dicing sheet of the present invention are described below.

[Layer A]
The layer A in the present invention has a ten-point average roughness Rz of 1.5 to 15.0 μm. In order to pick up the diced chips in the expanding step after dicing the semiconductor wafer, the semiconductor chips are expanded together with the dicing film on the dicing stage. At this time, if the ten-point average roughness Rz of the A layer is less than 1.5 μm, the sliding between the dicing stage and the dicing film is poor, and expansion cannot be performed well. In addition, when the ten-point average roughness Rz of the A layer is less than 1.5 μm, it is stored in a roll and fixed (blocked) between the A layer and the C layer of the dicing sheet base film during transportation, and is subsequently adhered. A problem arises when the roll is paid out in the processing process. On the other hand, when the ten-point average roughness Rz exceeds 15.0 μm, the slipperiness with respect to the dicing stage and the blocking property are improved, but the flatness of the dicing sheet base film tends to deteriorate.

In the present invention, in order to set the ten-point average roughness Rz to 1.5 to 15.0 μm, existing ethylene propylene rubber (EPR), block polypropylene blended with polyethylene (PE), ethylene propylene copolymer (EPC), Although inorganic particles may be used to roughen the surface, it is preferable to use small-sized organic fine particles. Specific examples of organic fine particles include polyethylene, polystyrene, polymethyl methacrylate, and the like, and the organic fine particles are more preferably polyethylene fine particles. The average particle size of the organic fine particles is preferably 30 µm or less, more preferably 20 µm or less, still more preferably 15 µm or less, and particularly preferably about 10 µm. By setting the average particle size of the organic fine particles to 30 μm or less, the surface of the layer A has moderate unevenness, and the slipperiness in the expanding step is improved. In addition, even if the obtained base film for a dicing sheet is produced and stored in a wound state, the contact surface is less likely to be damaged, and the organic fine particles are less likely to fall off. If the average particle size of the organic fine particles exceeds 30 μm, the formed film will be inferior in flatness due to the influence of coarse particles, and may cause foreign matter.

Although the material of layer A is not particularly limited in the present invention, it is preferably a polyolefin-based resin, more preferably a polyethylene-based resin, in consideration of compatibility with the layer B described later, expandability, and rupture resistance, Low-density polyethylene resins are particularly preferred.

[B layer]
In the present invention, low-density polyethylene is preferably used as the material of layer B in order to satisfy performance as a base film for a dicing sheet. Low-density polyethylene is roughly classified into high-pressure low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), and it is preferable to use linear low-density polyethylene, which has excellent breaking strength. Furthermore, among the linear low-density polyethylene, a linear low-density polyethylene polymerized with a metallocene catalyst is more preferable because of its excellent breaking strength.

In the present invention, the content of low-density polyethylene is 50% by weight to 100% by weight. This imparts appropriate flexibility to the layer B in the present invention and lowers the tensile elastic modulus, thereby exhibiting good expandability in the expanding step after the dicing step. The content of the low-density polyethylene is more preferably 70% to 100% by weight, more preferably 90% to 100% by weight, in consideration of flexibility. If the content of the low-density polyethylene is less than 50% by weight, sufficient toughness and flexibility cannot be obtained, and the dicing sheet base film tends to break during expansion.

The low-density polyethylene contained in the present layer B is preferably the same as the low-density polyethylene contained in the layer A from the viewpoint of improving adhesion between layers, but may be different. The low-density polyethylene contained in the layer B may be used alone, or two or more of them may be used in combination. The density of the low-density polyethylene resin is preferably 0.890-0.920 g/cm ³ . If ^the density of the low-density polyethylene resin is 0.890 g/cm ³ or more, the desired flexibility and handleability can be obtained. In some cases, the dicing sheet base film may be broken during expansion because the properties may not be obtained. In addition, shavings are likely to be generated in the dicing process of semiconductor wafers, which may cause process contamination.

[C layer]
An olefinic thermoplastic elastomer is used for the layer C in the present invention. By using the olefinic thermoplastic elastomer, cutting chips during dicing can be suppressed and sufficient expandability can be obtained.

Olefinic thermoplastic elastomers include olefin block copolymers, olefin random copolymers, ethylene copolymers, propylene copolymers, ethylene olefin block copolymers, propylene olefin block copolymers, ethylene olefin random copolymers, propylene olefin random copolymers, ethylene propylene random copolymers, ethylene (1 -butene) random copolymer, ethylene (1-pentene) olefin block copolymer, ethylene (1-hexene) random copolymer, ethylene (1-heptene) olefin block copolymer, ethylene (1-octene) olefin block copolymer, ethylene (1-nonene) ) olefin block copolymer, ethylene (1-decene) olefin block copolymer, propylene ethylene olefin block copolymer, ethylene (α-olefin) copolymer, ethylene (α-olefin) random copolymer, ethylene (α-olefin) block copolymer, amorphous polypropylene, Combinations of these with polyethylene (LLDPE, LDPE, HDPE (high-density polyethylene, or medium-low-pressure polyethylene from its manufacturing method), etc.), combinations of these with polypropylene, or combinations thereof can be mentioned.

The olefinic thermoplastic elastomer is preferably an α-olefinic thermoplastic elastomer. By adopting an α-olefin thermoplastic elastomer as the olefin thermoplastic elastomer, thermal stability is improved compared to other elastomer resins (e.g., styrene elastomers). It is possible to suppress heat deterioration during film formation when producing a film. In addition, by adopting an α-olefin thermoplastic elastomer as the olefin thermoplastic elastomer, the storage stability is improved compared to other elastomer resins (for example, styrene elastomer), and the base material for the dicing sheet of the present invention. It is possible to suppress fluctuations in physical property values while the film is being stored.

Further, in the present invention, if an α-olefinic thermoplastic elastomer is used as the olefinic thermoplastic elastomer, the steps in manufacturing the layer C can be simplified, and processing costs can be suppressed. This is because when other elastomer resins such as styrene-based elastomers are used, it is necessary to blend several types of styrene-based elastomers in order to control the physical properties, which complicates the work in the manufacturing process.

Employing an α-olefin thermoplastic elastomer as the olefin thermoplastic elastomer enables extrusion molding with a reduced number of resin types used in the production of the C layer, which eliminates the need to prepare many types of raw materials.

In the present invention, when an α-olefin thermoplastic elastomer is employed as the olefin thermoplastic elastomer, the α-olefin thermoplastic elastomer may be used alone or in a blend of two or more. Also good.

Examples of α-olefin thermoplastic elastomers include propylene elastomers, ethylene elastomers, 1-butene elastomers (propylene/ethylene copolymer, propylene/1-butene copolymer, propylene/ethylene/1-butene copolymer, Coalescence, 1-butene homopolymer, 1-butene/ethylene copolymer, 1-butene/propylene copolymer, 4-methylpentene-1 homopolymer, 4-methylpentene-1/propylene copolymer , 4-methylpentene-1/1-butene copolymer, 4-methylpentene-1/propylene/1-butene copolymer, or combinations thereof).

In the present invention, the α-olefin thermoplastic elastomer that can be employed as the olefin thermoplastic elastomer preferably has a density of 0.830 g/cm ³ to 0.890 g/cm ³ , more preferably 0.830 g/cm 3 to 0.890 g/cm 3 . 835 g/cm ³ to 0.888 g/cm ³ , more preferably 0.835 g/cm ³ to 0.886 g/cm ³ , particularly preferably 0.840 g/cm ³ to 0.885 g/cm ³ and most preferably 0.845 g/cm ³ to 0.885 g/cm ³ . By adopting an α-olefin thermoplastic elastomer whose density falls within the above range, it is possible to provide a base film for dicing sheets with superior cuttability, and other elastomers (e.g., styrene-based Elastomer), the thermal stability is further improved, for example, it is possible to further suppress thermal deterioration during film formation when manufacturing the base film for the dicing sheet of the present invention, and other elastomers ( For example, the storage stability is further improved compared to styrene-based elastomers), and it is possible to further suppress fluctuations in physical property values during storage of the base film for a dicing sheet of the present invention. The manufacturing process can be simplified, and the processing cost can be further suppressed.

In the present invention, the α-olefin thermoplastic elastomer that can be employed as the olefin thermoplastic elastomer has an MFR at 230° C. and 21.17 N, preferably 5.0 g/10 min to 25.0 g/10 min. Yes, more preferably 5.0 g / 10 minutes to 23.0 g / 10 minutes, still more preferably 5.0 g / 10 minutes to 21.0 g / 10 minutes, particularly preferably 5.0 g / 10 minutes to 20.0 g/10 min, most preferably 5.0 g/10 min to 19.0 g/10 min. By adopting an α-olefin thermoplastic elastomer whose MFR falls within the above range, it is possible to provide a base film for a dicing sheet having superior cuttability, and other elastomers (e.g., styrene-based Elastomer), the thermal stability is further improved, for example, it is possible to further suppress thermal deterioration during film formation when manufacturing the base film for the dicing sheet of the present invention, and other elastomers ( For example, the storage stability is further improved compared to styrene-based elastomers), and it is possible to further suppress fluctuations in physical property values during storage of the base film for a dicing sheet of the present invention. The manufacturing process can be simplified, and the processing cost can be further suppressed.

In the present invention, among the α-olefin thermoplastic elastomers that can be employed as the olefin thermoplastic elastomer, propylene elastomers are particularly preferred. By adopting a propylene-based elastomer as an olefin-based thermoplastic elastomer, it is possible to provide a base film for dicing sheets with extremely excellent cuttability, as well as other elastomers (e.g., styrene-based elastomers). Compared to other elastomers (e.g., , styrene elastomer), the storage stability is further improved, and it is possible to further suppress fluctuations in physical property values during storage of the base film for a dicing sheet of the present invention. The steps in manufacturing the layer can be further simplified, and processing costs can be further suppressed.

In the present invention, the C layer resin hardness is preferably 20 to 60 in Shore D hardness. In particular, as the olefinic thermoplastic elastomer, it is preferable that the propylene elastomer has a Shore D hardness of 20 to 60. If the Shore D hardness is less than 20, the adhesiveness of the film after film formation becomes strong, which may be a factor in deteriorating the blocking property. In addition, there is a concern that the physical properties may deteriorate, and it may cause breakage of the dicing film in the expanding process. On the other hand, when the Shore D hardness exceeds 60, the flexibility as a dicing film is lost, and extensibility and breakability in the expanding process may become a problem.

The above propylene-based elastomers are also available as commercial products. Examples of such commercial products include "Tafmer" (registered trademark) XM series manufactured by Mitsui Chemicals, Inc., "Tafmer" (registered trademark) PN series manufactured by Mitsui Chemicals, Inc., and "Vistamaxx" manufactured by ExxonMobil. (registered trademark) series (eg, Vistamax 6202, Vistamax 3980FL, etc.).

In the present invention, the α-olefinic thermoplastic elastomer that can be employed as the olefinic thermoplastic elastomer is preferably produced using a metallocene catalyst. The α-olefin thermoplastic elastomer produced using a metallocene catalyst makes it possible to provide a base film for dicing sheets with extremely excellent cuttability, and other elastomers (e.g., styrene elastomers ), the thermal stability is further improved, for example, it is possible to further suppress thermal deterioration during film formation when manufacturing the base film for a dicing sheet of the present invention, and other elastomers (for example, styrene elastomer), the storage stability is further improved, and it is possible to further suppress fluctuations in physical property values during storage of the base film for a dicing sheet of the present invention. , the steps in manufacturing the C layer can be further simplified, and the processing cost can be further suppressed.

The C layer may contain any appropriate other component within a range that does not impair the effects of the present invention. Such other ingredients include, for example, other polymers, tackifiers, plasticizers, antidegradants, pigments, dyes, antioxidants, antistatic agents, lubricants, foaming agents, heat stabilizers, light stabilizers. agents, inorganic fillers, organic fillers, and the like. These may be one kind or two or more kinds. The content of other components in layer C is preferably 10% by weight or less, more preferably 7% by weight or less, still more preferably 5% by weight or less, and particularly preferably 2% by weight or less. , most preferably not more than 1% by weight.

The thickness of the C layer is preferably 10 μm to 100 μm, more preferably 10 μm to 80 μm, still more preferably 10 μm to 60 μm, particularly preferably 20 μm to 50 μm. By keeping the thickness of the C layer within such a range, it is possible to provide a base film for a dicing sheet having superior dicing properties.

After the base film for a dicing sheet of the present invention is formed into a film, an adhesive is processed on the layer C, and the film is used as a dicing sheet in the dicing process and the expanding process of semiconductor wafers. The layer C on which the adhesive is processed is preferably surface-treated in order to improve the adhesiveness of the adhesive. Examples of surface treatment methods include mechanical treatments such as embossing and hairline treatment, physicochemical treatments such as plasma treatment, corona treatment and flame treatment, and chemical treatments such as primer treatment using a coupling agent. Among them, physicochemical treatments such as plasma treatment, corona treatment, and flame treatment are more preferable in consideration of their convenience and reduction of environmental load during treatment.

EXAMPLES The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to these examples. The present examples and comparative examples were evaluated using the following evaluation methods. The results are shown in Table 1.

(1) Ten-point average roughness Rz
Ten-point average roughness Rz is compliant with JIS B0601-2013 using a high-precision fine shape measuring instrument (SURFCORDER ET4000A) manufactured by Kosaka Laboratory Co., Ltd. 2 mm in the horizontal direction of the film and 0.2 mm in the vertical direction of the film. With respect to the range of , the scanning direction was set to the horizontal direction, and measurements were performed 11 times at intervals of 10 μm in the vertical direction, and three-dimensional analysis was performed and evaluated. A diamond stylus with a stylus tip radius of 2.0 μm was used, and the measurement was performed with a measuring force of 100 μN and a cutoff of 0.8 mm.

(2) Shore D hardness The hardness of the raw material used for the C layer was measured according to ASTM D2240.

(3) Evaluation of generation of burr (whiskers)-like chips A. Dicing A semi-automatic dicing saw (DAD-3350) manufactured by DISCO Corporation was used.
Blade: ZH05-SD4000-N1-70 ED
Blade rotation speed: 25000rpm
Cutting speed: 50mm/sec
Cut depth: 30 μm
Cutting water volume: 1.25 liters/min
Cutting water temperature: 23°C
Set the above conditions, set the A4 size film on the dicing saw, and set the film in the MD direction (Machine Direction: flow direction of the resin) with a length of 100 mm, three at 5 mm intervals, reverse 90 ° and also in the TD direction (Transverse Direction: Three surface layers were cut at 100 mm length and 5 mm intervals in the width direction of the resin.

B. Observation of Cut Surface Using an optical microscope VHX-5000 manufactured by Keyence, 9 points of a cross crossing MD and TD were observed.
Magnification: ×1000
Judgment criteria ◯: 0 burrs (whiskers) △: 1 to 4 burrs (whiskers) ×: 5 or more burrs (whiskers).

(4) Blocking evaluation A film sample with a width of 30 mm and a length of 100 mm was prepared, and the A layer (front surface) and the C layer (back surface) were overlapped in an area of 30 mm × 40 mm, and 4.9 N (0.5 kgf) / After applying a load of 12 cm ² and aging at 23° C. for 24 hours, the shear peel strength was measured using Tensilon manufactured by A&D at a tensile speed of 300 mm/min.
Judgment criteria ◯: less than 0.5 N/12 cm ² ×: 0.5 N/12 cm ² or more.

(5) Breakability evaluation A dicing sheet when a base film for a dicing sheet is fixed to a vinyl chloride resin pipe with a diameter of 6 inches and a needle with a diameter of 5 mm is pierced from above with a load of 14.7 N (1.5 kgf). The following criteria were used to evaluate the tearing of the base film for .
○: Not torn △: Partially torn ×: Torn.

<Polyethylene fine particle masterbatch>
(A1): High-molecular-weight polyethylene fine particles "Mipelon" PM200 manufactured by Mitsui Chemicals, Inc. with an average particle diameter of 10 µm and metallocene-based linear low-density polyethylene ("Evolue" SP1540 manufactured by Prime Polymer, MFR 3.8 g/min (190 ° C., 21.17 N)), and a polyethylene fine particle masterbatch (A1) consisting of a weight ratio of 10:90.
(A2): Crosslinked acrylic monodisperse particles MX-1500H manufactured by Soken Chemical Co., Ltd. having an average particle diameter of 15 μm and metallocene-based linear low-density polyethylene (“Evolue” SP1540 manufactured by Prime Polymer Co., Ltd., MFR 3.8 g / min (190 ° C., 21.17 N)), and an acrylic fine particle masterbatch (A2) consisting of a weight ratio of 10:90.

<Resin>
(PE1) Trade name “Evolue” SP1540, metallocene-based linear low-density polyethylene, manufactured by Prime Polymer, density 0.913 g/cm ³ , MFR 3.8 g/min (measured at 190°C, 21.17 N)
(PE2) Trade name "Harmolex" NH745N, metallocene-based linear low-density polyethylene, manufactured by Nippon Polyethylene Co., Ltd., density 0.913 g/cm ³ , MFR 8.0 g/min (measured at 190°C, 21.17 N)
(PE3) Trade name "Novatec" HF562, high-density polyethylene, manufactured by Nippon Polyethylene Co., Ltd., density 0.963 g/cm ³ , MFR 7.5 g/min (measured at 190°C, 21.17N)
(PE4) Trade name “Suntec” L6810, low-density polyethylene, manufactured by Asahi Kasei Corporation, density 0.918 g/cm ³ , MFR 10.5 g/min (measured at 190°C, 21.17N)
(PP1) Trade name "Vistamax" 3980FL, propylene-based elastomer, manufactured by Exxon Mobil, density 0.879 g/cm ³ , MFR 8.0 g/min (measured at 230°C, 21.17 N)
(PP2) Trade name "Tafmer" XM7070, propylene elastomer, manufactured by Mitsui Chemicals, density 0.870 g/cm ³ , MFR 7.0 g/min (measured at 230°C, 21.17 N).

(Example 1)
Constituent resins for each layer were prepared as follows.
Layer A: 90% by weight of (PE1) and 10% by weight of (A1) were used.
Layer B: 100% by weight of (PE1) was used.
C layer: 100% by weight of (PP1) was used.

Next, the constituent resin of each layer is put into each extruder of a T-die composite film forming machine having three extruders, and the A layer is 12.5 μm, the B layer is 67.5 μm, and the C layer is 20.0 μm. The discharge rate of each extruder was adjusted as above, and the layers were laminated in this order and extruded from a composite T die at an extrusion temperature of 210° C. to form a film having a total thickness of 100 μm.

After that, the laminate film obtained was evaluated by the method described above.

(Example 2)
Layer A: A laminated film was formed and evaluated in the same manner as in Example 1, except that the ratio of (PE1) was changed to 80% by weight and (A1) was changed to 20% by weight.

(Example 3)
Layer A: A laminate film was molded and evaluated in the same manner as in Example 1, except that the ratio of (PE1) was changed to 70% by weight and (A1) was changed to 30% by weight.

(Example 4)
A laminated film was molded and evaluated in the same manner as in Example 1, except that the layers A and B of Example 1 were changed from (PE1) to (PE2).

(Example 5)
A laminated film was molded and evaluated in the same manner as in Example 2, except that the polyolefin resin (polyethylene) of the A layer and the B layer of Example 2 was changed from (PE1) to (PE2).

(Example 6)
A laminated film was molded and evaluated in the same manner as in Example 3, except that the polyolefin resin (polyethylene) of the A layer and the B layer of Example 3 was changed from (PE1) to (PE2).

(Example 7)
A laminate film was formed and evaluated in the same manner as in Example 1, except that the layer C in Example 1 was changed from (PP1) to (PP2).

(Example 8)
A laminated film was molded and evaluated in the same manner as in Example 1 except that the layer B in Example 1 was changed from 100% by weight (PE1) to 50% by weight (PE1) and 50% by weight (PP1). carried out.

(Example 9)
A laminated film was formed and evaluated in the same manner as in Example 1, except that the layer A in Example 1 was changed from (A1) to (A2).

(Comparative example 1)
A laminated film was formed and evaluated in the same manner as in Example 1, except that the A layer of Example 1 was changed from 90% by weight (PE1) and 10% by weight (A1) to 100% by weight (PE1). carried out.

(Comparative example 2)
A laminate film was molded and evaluated in the same manner as in Example 1, except that the layer B in Example 1 was changed from (PE1) to (PE3).

(Comparative Example 3)
A laminate film was molded and evaluated in the same manner as in Example 1, except that (PP1) in the A layer of Example 1 was changed to (PE1).

(Comparative Example 4)
A laminate film was molded and evaluated in the same manner as in Example 1, except that (PP1) in the C layer of Example 1 was changed to (PE4).

(Comparative Example 5)
A laminate film was molded and evaluated in the same manner as in Example 1, except that (PP1) in the C layer of Example 1 was changed to (PE3).

From the results in Table 1, it can be seen that the Examples are films that suppress the generation of shavings during dicing, are less likely to cause blocking when wound into a roll, and are less likely to break.

On the other hand, in Comparative Example 1, blocking occurred because the surface roughness of the A layer was small. Comparative Example 2 is inferior in breaking strength because the layer B does not contain low-density polyethylene as a main component. Comparative Examples 3 to 5 do not use an olefinic thermoplastic elastomer for the layer C, and are likely to generate chips during dicing.

Claims (7)

A laminated film having at least an A layer, a B layer, and a C layer, wherein the A layer has a ten-point average roughness Rz of 1.5 to 15.0 μm, and the B layer contains low-density polyethylene, the low-density polyethylene content is 50% to 100% by weight, the C layer has an olefinic thermoplastic elastomer, and the A layer, the B layer, and the C layer are laminated in this order. wood film. 2. The base film for a dicing sheet according to claim 1, wherein said olefinic thermoplastic elastomer is an α-olefinic thermoplastic elastomer. 3. The base film for a dicing sheet according to claim 2, wherein the α-olefin thermoplastic elastomer is a propylene elastomer. The base film for a dicing sheet according to any one of claims 1 to 3, wherein the C layer resin hardness is 20 to 60 in Shore D hardness. The base film for a dicing sheet according to any one of claims 1 to 4, wherein the layer A contains organic fine particles having an average particle size of 30 µm or less. 6. The base film for a dicing sheet according to claim 5, wherein said organic fine particles are polyethylene fine particles. The base film for a dicing sheet according to any one of claims 1 to 6, wherein said layer C is flame-treated, plasma-treated or corona-treated.