TW201346001A - Adhesive sheet used in dicing - Google Patents

Abstract

The present invention provides an adhesive sheet used in dicing, which can suppress the production of cutting scraps and debris in a dicing step. The adhesive sheet used in dicing according to the present invention has an adhesive layer containing amorphous propylene-(1-butene) copolymer. The weight average molecular weight (Mw) of the amorphous propylene-(1-butene) copolymer is 200,000 or more. The molecular weight distribution (Mw/Mn) of the amorphous propylene-(1-butene) copolymer is 3 or less. In a preferred embodiment, the adhesive layer further contains a crystalline polypropylene-based resin.

Description

Cutting adhesive sheet

The present invention relates to an adhesive sheet for cutting.

Semiconductor wafers containing germanium, gallium, arsenic, etc. are manufactured in a large diameter state, and the back surface is ground after patterning on the surface. Usually, the thickness of the wafer is as thin as about 100 to 600 μm, and then the cutting is separated (dicing). ) is a small piece of the component (semiconductor wafer) and then transferred to the mounting step. Adhesive sheets are widely used in the manufacturing steps of such semiconductor wafers. For example, in the dicing step, a dicing adhesive sheet is used in order to fix the semiconductor wafer.

The semiconductor wafer is typically cut using a dicing blade during the dicing step. At this time, if the chips are generated from the adhesive sheet for cutting, the chips contaminate the semiconductor wafer and other members, and the reliability and yield of the electronic parts are reduced. As a technique for reducing the amount of chips generated from the adhesive sheet for dicing, it is proposed to reduce chipping from the substrate film by using an olefin-based thermoplastic elastomer having a specific structure and having a high melting point as a base film. (Patent Document 1). However, even with this technique, it is impossible to eliminate the chips from the adhesive which are generated by the adhesive blade being taken out by the cutting blade. Further, an adhesive sheet for dicing having a high elastic modulus adhesive layer has been proposed (Patent Document 2). However, even in this technique, the reduction effect of the chips is insufficient. Moreover, the adhesive layer of high modulus of elasticity does not have sufficient adhesion, and this problem cannot be solved in this technique.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-7654

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2005-159069

The present invention has been made to solve the above-mentioned problems, and an object of the invention is to provide a cutting adhesive sheet in which generation of chips is suppressed in a cutting step.

The dicing adhesive sheet of the present invention comprises an adhesive layer containing an amorphous propylene-(1-butene) copolymer, and the amorphous propylene-(1-butene) copolymer has a weight average molecular weight (Mw) of 200,000. As described above, the propylene-(1-butene) copolymer has a molecular weight distribution (Mw/Mn) of 3 or less.

In a preferred embodiment, the adhesive layer further contains a crystalline polypropylene resin.

In a preferred embodiment, the content ratio of the crystalline polypropylene-based resin is 50% by weight or less based on the total amount of the amorphous propylene-(1-butene) copolymer and the crystalline polypropylene-based resin. .

In a preferred embodiment, the adhesive layer has a storage modulus (G') at 20 ° C of 0.5 × 10 ⁶ Pa to 1.0 × 10 ⁸ Pa.

In a preferred embodiment, the dicing adhesive sheet of the present invention further comprises a substrate layer.

In a preferred embodiment, the thickness of the base material layer is 10% to 90% with respect to the total thickness of the adhesive layer and the base material layer.

In a preferred embodiment, the adhesive sheet for dicing of the present invention is obtained by molding the above-mentioned adhesive layer and the base material layer at one time.

According to the present invention, by providing an adhesive layer containing an amorphous propylene-(1-butene) copolymer having a specific weight average molecular weight and a molecular weight distribution, it is possible to provide a cutting adhesive which is suppressed in the generation of chips during the cutting step. sheet.

10‧‧‧Adhesive layer

20‧‧‧Substrate layer

100‧‧‧Cut adhesive sheets

Fig. 1 is a schematic cross-sectional view showing a cutting adhesive sheet according to a preferred embodiment of the present invention.

A. The overall composition of the adhesive sheet for cutting

Fig. 1 is a schematic cross-sectional view showing a cutting adhesive sheet according to a preferred embodiment of the present invention. The adhesive sheet 100 for dicing has the adhesive layer 10. The adhesive layer 10 contains an amorphous propylene-(1-butene) copolymer. The dicing adhesive sheet of the present invention may be a single layer sheet of the adhesive layer 10, or may further include a base material layer 20 as shown in FIG.

The thickness of the adhesive sheet 100 for cutting is preferably 50 μm to 300 μm, more preferably 75 μm to 200 μm, and particularly preferably 75 μm to 125 μm.

The thickness of the adhesive layer 10 is preferably from 10 μm to 300 μm, more preferably from 15 μm to 150 μm, and even more preferably from 30 μm to 100 μm. When the adhesive sheet for dicing does not have a substrate layer, the thickness of the adhesive layer is preferably from 50 μm to 300 μm, more preferably from 75 μm to 200 μm, and particularly preferably from 75 μm to 125 μm. When the adhesive sheet 100 for dicing is provided with the base material layer 20, the thickness of the adhesive layer 10 is preferably 10 μm to 150 μm, more preferably 15 μm to 100 μm, and particularly preferably 15 μm to 50 μm. It is 30 μm~50 μm. In the adhesive sheet for dicing of the present invention, even if the thickness of the adhesive layer is increased, the generation of debris (fragments of the semiconductor wafer) can be suppressed. Further, since the thickness of the adhesive layer can be increased, when the adhesive sheet for dicing of the present invention is used, the cutting step can be performed without cutting the cut into the substrate layer, and as a result, cutting from the substrate layer can be prevented. The production of chips.

The thickness of the substrate layer 20 is preferably from 10 μm to 150 μm, and more preferably from 20 μm to 100 μm.

The thickness of the base material layer 20 is preferably from 10% to 90%, and more preferably from 15% to 80%, based on the total thickness of the adhesive layer 10 and the base material layer 20.

The dicing adhesive sheet of the present invention may further comprise any other suitable layer. The other layer may be, for example, a base layer which is provided on the opposite side of the adhesive layer and which is viscous for cutting. The sheet is provided with a surface layer that imparts heat resistance. Further, an adhesive layer may be provided on the side opposite to the base material layer of the adhesive layer. In the case where the dicing adhesive sheet of the present invention has an adhesive layer, when the diced semiconductor wafer is peeled off, the adhesive layer is peeled off from the adhesive layer (that is, the adhesive layer is peeled off from the semiconductor wafer). The adhesive layer functions as an adhesive layer when the wafer is mounted on the substrate or as an adhesive between the wafers when the wafer is stacked in multiple layers. As the adhesive in the adhesive layer, a previously known semiconductor adhesive can be used.

The dicing adhesive sheet of the present invention can be provided by a separator. The dicing adhesive sheet of the present invention can be wound into a roll shape in a state protected by a separator. The separator has a function as a protective sheet for protecting the cutting adhesive sheet until it is supplied for practical use. Examples of the separator include a plastic coated with a release agent such as a bismuth release agent, a fluorine release agent, or a long-chain alkyl acrylate release agent (for example, polyethylene terephthalate (PET). , polyethylene, polypropylene) film, non-woven fabric or paper.

When the adhesive sheet for dicing of the present invention is not protected by the separator, for example, the outermost layer on the side opposite to the adhesive layer may be subjected to back treatment. The back surface treatment can be carried out, for example, using a release agent such as a ruthenium release agent or a long-chain alkyl acrylate release agent. The adhesive sheet for dicing of the present invention can be wound into a roll shape by performing back surface treatment.

B. Adhesive layer

The above adhesive layer contains an amorphous propylene-(1-butene) copolymer. The adhesive sheet for dicing of the present invention can suppress the generation of chips from the adhesive layer in the cutting step by providing such an adhesive layer. Further, even if the thickness of the adhesive layer is increased by the inclusion of the amorphous propylene-(1-butene) copolymer, the generation of chips can be suppressed. Further, since the thickness of the adhesive layer can be increased, when the adhesive sheet for dicing of the present invention is used, the cutting step can be performed without cutting the cut into the substrate layer, and as a result, cutting from the substrate layer can be prevented. The production of chips. In the present specification, "amorphous" means a property which does not have a melting point as defined by crystallinity.

The above adhesive layer may be a single layer or may contain a component containing ratio (for example, amorphous A multilayered body of a layer having a different propylene-(1-butene) copolymer and/or a crystalline polypropylene-based resin (described later).

As described above, the dicing adhesive sheet of the present application suppresses the chips from the adhesive layer in the cutting step, and the mechanism is presumed as follows. The chips from the adhesive layer in the cutting step can be considered as the separator from the adhesive layer which is heated by the adhesive layer and then cooled by cooling. Here, heating specifically refers to heat generated by friction with a blade, and the adhesive layer is rapidly heated due to the heat. The above cooling specifically refers to cooling by cooling water. The adhesive for the previous adhesive sheet for dicing (for example, an acrylic adhesive) is composed of a crosslinked resin for ensuring cohesiveness, and is softened by the above heating without fluidity. Therefore, at the time of dicing, the cohesive adhesive is carried out by the blade and adheres to the semiconductor wafer, and is cooled to remain on the semiconductor wafer in the form of chips from the adhesive layer. On the other hand, the adhesive layer of the dicing adhesive sheet of the present invention has an amorphous propylene-(1-butene) copolymer, and the desired cohesive force can be ensured even without crosslinking. Since the adhesive layer of the dicing adhesive sheet of the present invention is not mainly composed of a crosslinked resin, the adhesive layer has fluidity by the above heating, and it is estimated that it is discharged to the outside of the system at the time of cutting. As a result, it is estimated that contamination of the semiconductor wafer can be prevented without generating chips from the adhesive layer.

The amorphous propylene-(1-butene) copolymer has a molecular weight distribution (Mw/Mn) of 3 or less, preferably 2 or less, more preferably 1.1 to 2, and still more preferably 1.2 to 1.9. The amorphous propylene-(1-butene) copolymer having a molecular weight distribution (Mw/Mn) in this range has a small amount of low molecular weight components, and thus the cutting adhesive sheet of the present invention has a cutting chip from the adhesive layer in the cutting step. The generation is suppressed, and the chipping resistance (inhibition of semiconductor wafer chips) is excellent. Further, contamination of the semiconductor wafer caused by bleeding of the low molecular weight component can be prevented.

The amorphous propylene-(1-butene) copolymer has a weight average molecular weight (Mw) of 200,000 or more, preferably 200,000 to 500,000, more preferably 200,000 to 300,000. If it is within this range, the cut from the adhesive layer in the cutting step can be obtained. A cutting adhesive sheet which is suppressed in the generation of shavings and is excellent in chipping resistance. Further, contamination of the semiconductor wafer caused by bleeding of the low molecular weight component can be prevented. Further, when co-extrusion molding is used for forming the dicing adhesive sheet, the adhesive layer can be formed without processing. Further, the adhesive sheet for dicing having an adhesive layer containing an amorphous propylene-(1-butene) copolymer having a weight average molecular weight (Mw) in the above range is available without a base material layer. Rational in the actual use.

The amorphous propylene-(1-butene) copolymer may be any suitable copolymer as long as the desired properties are obtained. An amorphous propylene-(1-butene) copolymer obtained by polymerizing propylene with 1-butene by using a metallocene catalyst is preferably used. Such an amorphous propylene-(1-butene) copolymer can be obtained, for example, by carrying out a polymerization step of polymerizing propylene and 1-butene using a metallocene catalyst, after which the residue is carried out. Post-processing steps such as a catalyst removal step and a foreign matter removal step. The amorphous propylene-(1-butene) copolymer can be obtained, for example, in the form of a powder or a pellet by the above steps. Examples of the metallocene catalyst include a metallocene-supporting catalyst containing a metallocene compound and a metallocene uniformly mixed with a catalyst, and a metallocene-supporting catalyst having a metallocene compound supported on a particulate carrier.

In the amorphous propylene-(1-butene) copolymer, the content ratio of the constituent unit derived from propylene is preferably from 80 mol% to 99 mol%, more preferably from 85 mol% to 99 mol%, particularly preferably 90 mol% to 99 mol%.

In the amorphous propylene-(1-butene) copolymer, the content ratio of the constituent unit derived from 1-butene is preferably from 1 mol% to 15 mol%, more preferably from 1 mol% to 10 mol%. When it is in such a range, it is excellent in the balance of a toughness and a softness, and the adhesive sheet for cutting which is excellent in the followability of the uneven surface.

The above amorphous propylene-(1-butene) copolymer may be a block copolymer or a random copolymer.

The melt flow rate of the amorphous propylene-(1-butene) copolymer at 230 ° C and 2.16 kgf is preferably from 1 g/10 min to 50 g/10 min, and further preferably 5 g/10 min. ~30 g/10 min, especially 5 g/10 min~20 g/10 min. When the melt flow rate of the amorphous propylene-(1-butene) copolymer is within this range, the adhesive layer can be formed with good formability. For example, when co-extrusion molding is used for forming the adhesive sheet for dicing, An adhesive layer having a uniform thickness is formed without processing. The melt flow rate can be measured by the method according to JIS K7210.

The amorphous propylene-(1-butene) copolymer may also contain constituent units derived from other monomers without departing from the effects of the present invention. Examples of the other monomer include ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1-pentene. And other alpha-olefins.

The pressure-sensitive adhesive layer preferably further contains a crystalline polypropylene resin. By including a crystalline polypropylene-based resin, the storage modulus of the adhesive layer can be increased. As a result, the chipping resistance of the adhesive sheet for dicing can be improved. Further, an adhesive sheet for dicing excellent in handleability can be obtained. Such an adhesive sheet for dicing is excellent even if it does not have the handleability of a base material layer. Further, by including the crystalline polypropylene-based resin, the adhesive strength of the adhesive layer can be lowered to obtain a dicing adhesive sheet excellent in balance between adhesive strength and peelability.

The content ratio of the crystalline polypropylene-based resin is preferably 50% by weight or less based on the total weight of the amorphous propylene-(1-butene) copolymer and the crystalline polypropylene-based resin. It is preferably 40% by weight or less, and particularly preferably 30% by weight or less. If it is in this range, the generation of chips from the adhesive layer in the cutting step can be suppressed, and the chipping resistance can be improved. Moreover, the dicing adhesive sheet which is excellent in the balance of adhesive force and peeling property, ie, the dicing adhesive sheet which can fully fix a semiconductor wafer at the time of dicing, and can be easily peeled off when picking up a semiconductor wafer is obtained. On the other hand, when the content ratio of the crystalline polypropylene-based resin is more than 50% by weight, the storage number (G') of the adhesive layer is improved, and the chipping resistance can be improved, but the adhesion is lowered, and the wafer is The maintenance is reduced.

The above crystalline polypropylene-based resin may be a homopolypropylene or a copolymer obtained from a monomer copolymerizable with propylene and propylene. As a monomer copolymerizable with propylene, for example Examples thereof include α-olefins such as ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1-pentene.

The crystalline polypropylene-based resin is preferably obtained by polymerization using a metallocene catalyst as in the case of the amorphous propylene-(1-butene) copolymer. When the crystalline polypropylene-based resin obtained in this manner is used, contamination of the semiconductor wafer due to bleeding of the low molecular weight component can be prevented.

The crystallinity of the crystalline polypropylene-based resin is preferably 10% or more, and more preferably 20% or more. The degree of crystallinity is typically determined by differential scanning calorimetry (DSC) or X-ray diffraction.

The storage modulus (G') of the above adhesive layer at 20 ° C is preferably from 0.5 × 10 ⁶ Pa to 1.0 × 10 ⁸ Pa, more preferably from 1.0 × 10 ⁶ Pa to 8.0 × 10 ⁷ Pa, particularly preferably 1.5 × 10 ⁶ Pa ~ 5.0 × 10 ⁷ Pa. The dicing adhesive sheet of the present invention has a storage modulus (G') in this range, and is excellent in balance between adhesion and peelability. When the storage modulus (G') of the pressure-sensitive adhesive layer is in the above range, a cutting adhesive sheet excellent in chipping resistance and having sufficient adhesion can be obtained. More specifically, when the storage modulus (G') of the pressure-sensitive adhesive layer is 0.5 × 10 ⁶ Pa or more, the vibration of the adhesive layer during dicing can be suppressed and the generation of debris can be prevented. Further, when the storage modulus (G') of the pressure-sensitive adhesive layer is 1.0 × 10 ⁸ Pa or less, it has sufficient adhesion, and the semiconductor wafer (wafer) can be satisfactorily fixed at the time of dicing to prevent the wafer from scattering. In addition, when the storage modulus (G') of the pressure-sensitive adhesive layer is in the above range, a cutting adhesive sheet excellent in handleability can be obtained. Further, even when the surface of the semiconductor wafer has irregularities, an adhesive sheet for cutting which can follow the irregularities can be obtained. If such an adhesive sheet for cutting is used, contamination of the semiconductor wafer by the cutting water during the cutting step can be prevented. Further, the storage modulus (G') in the present invention can be measured by dynamic viscoelastic spectroscopy.

The adhesive layer preferably has an adhesion of 0.3 N/20 mm to 3.0 N/20 mm, more preferably 0.4 N/20 mm to 2.5 N/20 mm, and particularly preferably 0.4 N/20 mm to 2.0 N/ 20 mm, preferably 0.9 N/20 mm~2.0 N/20 mm. If it is within this range, A cutting adhesive sheet excellent in balance between adhesion and peelability is obtained. Further, in the present specification, the adhesive force of the adhesive layer means that the adhesive sheet for dicing of the present invention is aged at 50 ° C for 2 days, and then a semiconductor mirror wafer (manufactured by 矽) is used as a test plate, and the use is based on JIS Z. The method of 0237 (2000) (temperature: 23 ° C, bonding conditions: 2 kg roll back and forth, peeling speed: 300 mm / min, peeling angle 180 °) measured adhesion.

The above adhesive layer may also contain other components without departing from the scope of the effects of the present invention. Examples of the other component include an antioxidant, an ultraviolet absorber, a light stabilizer, a heat stabilizer, and an antistatic agent. The types and amounts of other ingredients can be appropriately selected depending on the purpose.

C. substrate layer

As the material constituting the above substrate layer, any appropriate material can be employed. Examples of the material constituting the base material layer include polyester resins such as polyethylene terephthalate (PET); polyolefin resins such as polyethylene (PE) and polypropylene (PP); and polyimine. (PI); ethylene-vinyl acetate copolymer (EVA); polyetheretherketone (PEEK); polyvinyl chloride resin such as polyvinyl chloride (PVC); polystyrene resin; acrylic resin; fluorine resin; Cellulose resin; polycarbonate resin. As the formability, a thermoplastic resin can be preferably used. The substrate layer can be a multilayer construction comprising the same or different materials.

The melt flow rate of the material constituting the base material layer at 190 ° C and 2.16 kgf is preferably 2 g/10 min to 20 g/10 min, and more preferably 5 g/10 min to 15 g/10 min. Good for 7 g/10 min~12 g/10 min. When the melt flow rate of the material constituting the base material layer is within this range, when the co-extrusion molding is used for the formation of the dicing adhesive sheet, the base material layer can be formed without processing.

The base material layer may also contain other components without departing from the scope of the effects of the present invention. As the other component, for example, the same components as those which may be contained in the adhesive layer described in the above item B can be used.

D. Method for manufacturing adhesive sheet for cutting

Examples of the method for molding the dicing adhesive sheet of the present invention include inflation molding, calender molding, and extrusion molding.

In the case where the dicing adhesive sheet of the present invention has the above-mentioned base material layer, the dicing adhesive sheet of the present invention is preferably obtained by molding the above-mentioned pressure-sensitive adhesive layer and the above-mentioned base material layer at one time. Examples of such a molding method include inflation molding, calender molding, and coextrusion molding. Among them, coextrusion molding is preferred. By co-extrusion molding, a cutting adhesive sheet having good interlayer adhesion can be produced with a small number of steps and without using an organic solvent.

In the above coextrusion molding, a material obtained by mixing the components of the above layers by any appropriate method may be used as the material for forming the pressure-sensitive adhesive layer and the base material layer.

As a specific method of the co-extrusion molding, for example, in at least two extruders connected to a die, one of the adhesive layer forming materials is supplied to one, and the other is supplied to the other. The material forming material is melted, extruded, and drawn by a contact roll forming method to form a laminate. The closer the portion where the forming materials are joined during extrusion, the closer to the nozzle outlet (mould lip). The reason for this is that it is difficult to cause a merge failure of each of the formed materials in the nozzle. Therefore, as the above-mentioned nozzle, a nozzle in the form of a multi-manifold is preferably used. Further, in the case where the merging failure occurs, appearance defects such as merging unevenness occur, and specifically, the appearance of the wavy appearance between the extruded adhesive layer and the substrate layer is uneven, which is not preferable. Further, the merging failure occurs, for example, because the difference in fluidity (melt viscosity) between the different kinds of material forming materials in the nozzle is large, and the difference in the shear rate of the material forming the layers is large, so that a multi-manifold form is used. In the case of the nozzle, the material selection range of the different kinds of forming materials having poor fluidity is expanded compared to other forms (for example, in the form of a feed module). The type of screw used for the extruder for melting each of the formed materials may be uniaxial or biaxial. The extruder can also be three or more. When the adhesive layer is a multilayer body, three or more extruders are used. Further, when the number of extruders is three or more, the material for forming the other layers can be further supplied. When a two-layer extruder is used to produce a two-layer structure (base material layer + adhesive layer) for the cutting of the adhesive sheet, the same forming material may be supplied to two or more adjacent extruders. For example, using 3 extruders In the case of the case, the same forming material can be supplied to two adjacent extruders.

The molding temperature in the above coextrusion molding is preferably from 160 ° C to 220 ° C, more preferably from 170 ° C to 200 ° C. When it exists in this range, it is excellent in shaping|molding stability.

The difference between the adhesive layer forming material and the base material forming material at a temperature of 180 ° C and a shear rate of 100 sec ^-1 (adhesive forming material - base material forming material), preferably -150 Pa. s~600 Pa. s, and further preferably -100 Pa. s~550 Pa. s, especially good for -50 Pa. s~500 Pa. s. When it is in this range, the adhesive forming material and the base material layer forming material have similar fluidity in the nozzle, and the occurrence of merging failure can be prevented. Further, the shear viscosity can be measured using a double capillary type elongational viscometer.

[Examples]

Hereinafter, the present invention will be specifically described by way of Examples, but the present invention is not limited by the Examples. Further, in the examples, "parts" and "%" are based on weight unless otherwise specified.

[Example 1]

As the adhesive layer forming material, an amorphous propylene-(1-butene) copolymer obtained by polymerization using a metallocene catalyst (manufactured by Sumitomo Chemical Co., Ltd., trade name "Tafthren H5002": composition from propylene is used. The unit 90 mol% / constituent unit from 1-butene 10 mol%, Mw = 230,000, Mw / Mn = 1.8).

As the base layer forming material, an ethylene-vinyl acetate polymer (EVA) (manufactured by Mitsui DuPont Co., Ltd., trade name "EVAFLEX P-1007") was used.

The adhesive forming material and the substrate layer forming material were placed in respective extruders, and T-die melt-co-extrusion was performed (extruder: GM ENGINEERING, trade name "GM30-28"/T Type die mouth: feeding module method; extrusion temperature: 180 ° C), a pressure-sensitive adhesive sheet having a thickness of 30 μm of the adhesive layer and a thickness of the substrate layer of 70 μm was obtained. Furthermore, the thickness of each layer is controlled by the shape of the T-die outlet.

[Embodiment 2]

As the adhesive layer forming material, 80 parts of an amorphous propylene-(1-butene) copolymer polymerized by a metallocene catalyst (manufactured by Sumitomo Chemical Co., Ltd., trade name "Tafthren H5002": from propylene was used. The constituent unit is 90 mol% / 10 mol% from 1-butene, Mw = 230,000, Mw / Mn = 1.8), and 20 parts of crystalline polypropylene resin polymerized by metallocene catalyst An adhesive sheet for dicing was obtained in the same manner as in Example 1 except that a mixture (manufactured by Japan Polypropylene Co., Ltd., trade name "WINTEC WFX4", Mw = 363,000, Mw/Mn = 2.87) was used.

[Example 3]

As the first adhesive layer forming material, 80 parts of an amorphous propylene-(1-butene) copolymer polymerized by a metallocene catalyst (manufactured by Sumitomo Chemical Co., Ltd., trade name "Tafthren H5002" was used: 90 mol% from propylene, 10 mol% from 1-butene, Mw=230,000, Mw/Mn=1.8), and 20 parts of crystalline polypropylene polymerized by metallocene catalyst A mixture of a resin (manufactured by Japan Polypropylene Co., Ltd., trade name "WINTEC WFX4", Mw = 363,000, Mw/Mn = 2.87).

As the second adhesive layer forming material, an amorphous propylene-(1-butene) copolymer polymerized by a metallocene catalyst (manufactured by Sumitomo Chemical Co., Ltd., trade name "Tafthren H5002": from propylene is used. The constituent unit is 90 mol% / 10 mol% from 1-butene, Mw = 230,000, Mw / Mn = 1.8).

As the base layer forming material, an ethylene-vinyl acetate polymer (manufactured by Mitsui DuPont, trade name "EVAFLEX P-1007") was used.

The first adhesive layer forming material, the second adhesive layer forming material, and the base material layer forming material are placed in respective extruders to perform T-die melt co-extrusion (extruder: GM ENGINEERING Manufactured, the product name "GM30-28" / T-type nozzle: feeding module method; extrusion temperature 180 ° C), the thickness of the adhesive layer is 30 μm (1st Thickness of adhesive layer: 20 μm, thickness of second adhesive layer: 10 μm), adhesive sheet for cutting of 70 μm of substrate layer (first adhesive layer / second adhesive layer / substrate layer) ). Furthermore, the thickness of each layer is controlled by the shape of the T-die exit.

[Example 4]

As the first adhesive layer forming material, 70 parts of an amorphous propylene-(1-butene) copolymer polymerized by a metallocene catalyst (manufactured by Sumitomo Chemical Co., Ltd., trade name "Tafthren H5002" was used: 90 mol% of constituent units derived from propylene/10 mol% of constituent units derived from 1-butene, Mw=230,000, Mw/Mn=1.8), and 30 parts of crystalline polypropylene obtained by polymerization of a metallocene catalyst An adhesive sheet for dicing was obtained in the same manner as in Example 3 except that a mixture of a resin (manufactured by Japan Polypropylene Co., Ltd., trade name "WINTEC WFX4", Mw = 363,000, Mw/Mn = 2.87) was used.

[Example 5]

As the first adhesive layer forming material, 60 parts of an amorphous propylene-(1-butene) copolymer polymerized by a metallocene catalyst (manufactured by Sumitomo Chemical Co., Ltd., trade name "Tafthren H5002" was used: 90 mol% from propylene, 10 mol% from 1-butene, Mw=230,000, Mw/Mn=1.8), and 40 parts of crystalline polypropylene polymerized by metallocene catalyst An adhesive sheet for dicing was obtained in the same manner as in Example 3 except that a mixture of a resin (manufactured by Japan Polypropylene Co., Ltd., trade name "WINTEC WFX4", Mw = 363,000, Mw/Mn = 2.87) was used.

(Comparative Example 1)

An adhesive sheet was obtained in the same manner as in Example 1 except that a thermoplastic acrylic resin (trade name: "LA2140e": Mw = 74,000, Mw/Mn = 1.3) was used as the adhesive layer forming material. .

(Comparative Example 2)

78 parts of 2-ethylhexyl acrylate and 19 parts of acrylonitrile were added to the flask at 25 °C. Porphyrin, 3 parts of acrylic acid, 0.1 part of 2,2'-azobisisobutyronitrile, and 200 parts of ethyl acetate as a diluent solvent. Then, nitrogen gas was introduced into the flask while stirring for about 1 hour, and the inside air was replaced with nitrogen. Then, the flask was heated, the temperature in the flask was raised to 60 ° C, and ethyl acetate was added dropwise thereto for about 6 hours to carry out polymerization to obtain a polymer solution. Two parts of a polyisocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATE L") and one part of a polyfunctional epoxy compound (Mitsubishi Gas Chemical Co., Ltd., trade name) are added to 100 parts of the obtained polymer solid content. After "Tetrad C"), it was diluted with ethyl acetate and stirred until it became uniform to obtain an adhesive solution.

The obtained adhesive solution was coated on a PET separator, and dried at 130 ° C for 5 minutes in a drying oven to form an adhesive layer having a thickness of 30 μm.

The obtained adhesive layer was transferred onto an ethylene-vinyl acetate copolymer (EVA) film to obtain a first adhesive layer (acrylic resin, thickness: 30 μm) and a substrate layer (EVA, thickness: 70 μm). ) The adhesive sheet for cutting. Further, an ethylene-vinyl acetate copolymer (EVA) film was obtained by extrusion molding a product of the name "EVAFLEX P-1007" manufactured by Mitsui DuPont.

(Comparative Example 3)

40 parts of 2-ethylhexyl acrylate, 50 parts of methyl acrylate, 10 parts of acrylic acid, 0.2 part of benzoyl peroxide, and 100 parts of ethyl acetate as a diluent solvent were placed in a flask at 25 °C. Then, nitrogen gas was introduced into the flask while stirring for about 1 hour, and the inside air was replaced with nitrogen. Then, the flask was heated, the temperature in the flask was raised to 65 ° C, and ethyl acetate was appropriately added dropwise thereto to carry out polymerization for about 6 hours to obtain a polymer solution. 50 parts of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name "DPHA") and 3 parts of photopolymerization initiator (manufactured by BASF Corporation) were added to 100 parts of the obtained polymer solid content. "IRGACURE 651"), 3 parts of polyisocyanate compound (manufactured by Nippon Polyurethane Industry, trade name "CORONATE L"), and 0.5 part of polyfunctional epoxy compound (Mitsubishi Gas Chemical, After the product name is "Tetrad C", it was diluted with ethyl acetate and stirred until it became uniform to obtain an adhesive solution.

The obtained adhesive solution was coated on a PET separator, and dried at 130 ° C for 5 minutes in a drying oven to form an adhesive layer having a thickness of 30 μm.

The obtained adhesive layer was transferred onto an ethylene-vinyl acetate copolymer (EVA) film to obtain a first adhesive layer (acrylic resin, thickness: 30 μm) and a substrate layer (EVA, thickness: 70 μm). ) The adhesive sheet for cutting. Further, an ethylene-vinyl acetate copolymer (EVA) film was obtained by extrusion molding a product of the name "EVAFLEX P-1007" manufactured by Mitsui DuPont.

(Comparative Example 4)

40 parts of 2-ethylhexyl acrylate, 50 parts of methyl acrylate, 10 parts of acrylic acid, 0.2 part of benzoyl peroxide, and 100 parts of ethyl acetate as a diluent solvent were placed in a flask at 25 °C. Then, nitrogen gas was introduced into the flask while stirring for about 1 hour, and the inside air was replaced with nitrogen. Then, the flask was heated, the temperature in the flask was raised to 65 ° C, and ethyl acetate was appropriately added dropwise thereto to carry out polymerization for about 6 hours to obtain a polymer solution. 70 parts of acrylamide (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name "UV-1700B") and 30 parts of urethane acrylate (made in Japan) were added to 100 parts of the obtained polymer solid content. Manufactured by Chemical Company, trade name "UV-3000B"), 3 parts of photopolymerization initiator (manufactured by BASF Corporation, trade name "IRGACURE 651"), and 3 parts of polyisocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name After "CORONATE L", it was stirred while being diluted with ethyl acetate until it became uniform, and an adhesive solution was obtained.

The obtained adhesive solution was coated on a PET separator, and dried at 130 ° C for 5 minutes in a drying oven to form an adhesive layer having a thickness of 30 μm.

The obtained adhesive layer was transferred onto an ethylene-vinyl acetate copolymer (EVA) film to obtain a first adhesive layer (acrylic resin, thickness: 30 μm) and a substrate layer (EVA, thick). Degree: 70 μm) The adhesive sheet for cutting. Further, an ethylene-vinyl acetate copolymer (EVA) film was obtained by extrusion molding a product of the name "EVAFLEX P-1007" manufactured by Mitsui DuPont.

(Comparative Example 5)

As the adhesive layer forming material, a crystalline polypropylene resin (manufactured by Japan Polypropylene Co., Ltd., trade name "WINTEC WFX4", Mw = 363,000, Mw/Mn = 2.87), which is polymerized by a metallocene catalyst, is used. Otherwise, an adhesive sheet for dicing was obtained in the same manner as in Example 1.

[Evaluation]

The dicing adhesive sheets obtained in the examples and the comparative examples were evaluated by the following methods. The results are shown in Table 1.

(die splash)

A 6-inch semiconductor wafer having a thickness of 250 μm was mounted on the adhesive sheet for dicing, and the dicing was performed under the following conditions.

<Cutting conditions>

Cutting machine: DISCO-651 manufactured by DISCO

Blade: DISCO company manufactures NBC-ZH2050 27HECC

Blade speed: 40000 rpm

Cutting speed: 80 mm / sec

Cutting size: 2.5 mm × 2.5 mm

Cutting mode: undercut

Cutting with adhesive sheet: 20 μm

After the dicing, the presence or absence of the remaining semiconductor wafers obtained by the dicing of the semiconductor wafer was observed with an optical microscope (20 times), and the number of splatters of the dies was counted. Further, the number of splatters of the wafer having a substantially triangular shape generated by the outer peripheral portion of the wafer and the number of splatters of the wafer of the quadrangular shape generated inside the wafer are counted. Table 1 shows The ratio of the number of splatter splats to the total number of diced semiconductor wafers.

(debris)

100 wafers were taken as samples from each of the semiconductor wafers obtained from the evaluation of the above-mentioned slab splash, and the wafer was placed on the glass plate with the double-sided line (fourth line) as shown above. Tape made on the sample stage. The depth of the chipping (debris) from the back side of the wafer was measured by observing it from the upper portion with an optical microscope (200 times). The largest crumb depth in 100 wafers is shown in Table 1.

(chip from the adhesive layer)

The side faces of the semiconductor wafer of 100 wafers were observed in the same manner as the evaluation of the above-mentioned chips, and it was confirmed whether or not the chips on the side faces of the semiconductor wafer were from the adhesive layer. Further, the chips from the adhesive layer having a long diameter of 5 μm or more were observed.

(pick up)

Cutting was performed in the same manner as the evaluation of the splatter of the slab except that the dicing size was set to 5 mm × 5 mm. In Comparative Examples 3 and 4 which are ultraviolet curable adhesives, ultraviolet rays were irradiated from the adhesive surface under the conditions shown below, and were used as pick-up evaluation workpieces. The pickup evaluation was carried out under the conditions shown below. Further, the needle height was 200 μm, and when the pickup could not be performed, the needle height was increased every 10 μm, and the needle height at the time of continuously picking 50 wafers was used as the evaluation value of the pickup property. The smaller the value of the evaluation value, the better the pick-up property, and if the needle height is 1000 μm or less, it is rated as a good pick.

(pick condition)

Device FED-1870 (made by Shibaura Co., Ltd.)

Picking speed index 4

Pick up time 100 msec

Starting capacity from 200 μm

Expansion amount 3 mm

Needle configuration 3 × 3 mm

Needle R 250 μm

Nozzle size 5×5 mm

(UV irradiation conditions)

Device UM-810 (made by Nitto Seiki Co., Ltd.)

UV illumination 50 mW/cm ²

UV irradiation time 6 seconds

UV light amount 300 mJ/cm ²

(storage modulus)

The storage modulus (G') of the adhesive layer used in the examples and the comparative examples was evaluated by the following method.

A test piece (thickness 2 mm × 7.9 mm) was prepared using the adhesive layer forming material used in the examples. Using a dynamic viscoelasticity measuring device (manufactured by Rheometric Scientific, product name "ARES"), the storage modulus of the shear was measured at a frequency of 1 Hz, a temperature increase rate of 5 ° C / min, and a range of -50 ° C to 100 ° C (G). ').

Since a part of the measurement was not possible, the sample was measured using a tensile test. A sample of an adhesive layer having a width of 10 mm and a length of 80 mm was used at 23 ° C using a tensile tester (manufactured by Shimadzu Corporation, TENSILON) at a distance of 50 mm between the chucks and a tensile speed of 0.3 m/min. The stretching was performed in the longitudinal direction, and the stress-strain curve was measured. The tensile modulus of elasticity is calculated by the following formula (I).

Et = (σ2-σ1) / (ε2-ε1). . . . . (I)

Et: tensile elastic modulus [MPa]

Σ1: tensile stress [MPa] of strain ε1=0.05%

Σ2: tensile stress [MPa] of strain ε2=0.25%

(adhesion (peeling speed 300 mm/min))

The obtained adhesive sheet for dicing was aged at 50 ° C for 2 days, and then attached to a mirror surface of a 4 inch semiconductor wafer (manufactured by 矽), using a method according to JIS Z 0237 (2000) (temperature: 23 ° C, bonding conditions: 2 kg roller reciprocating once, peeling speed: 300 mm / min, peeling angle: 180 °) was measured.

According to the embodiment, it is clear that according to the present invention, the generation of chips in the cutting step can be obtained by providing an adhesive layer containing an amorphous propylene-(1-butene) copolymer having a specific weight average molecular weight and a molecular weight distribution. Squeezed adhesive sheet for suppression.

10‧‧‧Adhesive layer

20‧‧‧Substrate layer

100‧‧‧Cut adhesive sheets

Claims (7)

An adhesive sheet for dicing, comprising an adhesive layer containing an amorphous propylene-(1-butene) copolymer, and the amorphous propylene-(1-butene) copolymer has a weight average molecular weight (Mw) of 200,000 As described above, the propylene-(1-butene) copolymer has a molecular weight distribution (Mw/Mn) of 3 or less. The adhesive sheet for dicing according to claim 1, wherein the adhesive layer further comprises a crystalline polypropylene resin. The adhesive sheet for dicing according to claim 2, wherein a content ratio of the crystalline polypropylene-based resin is a total amount of the amorphous propylene-(1-butene) copolymer and the crystalline polypropylene-based resin. 50% by weight or less. The adhesive sheet for cutting according to claim 1 or 2, wherein the storage modulus (G') of the adhesive layer at 20 ° C is 0.5 × 10 ⁶ Pa to 1.0 × 10 ⁸ Pa. The dicing adhesive sheet according to claim 1 or 2, further comprising a substrate layer. The dicing adhesive sheet according to claim 5, wherein the thickness of the base material layer is 10% to 90% with respect to a total thickness of the adhesive layer and the base material layer. The dicing adhesive sheet according to claim 5, wherein the adhesive layer and the base material layer are formed at one time.