TW201336961A - Adhesive sheet with separating film - Google Patents

Abstract

The invention provides an adhesive sheet with a separating film. Excellent processing is provided, after stripping of the separating film, proper adhesive force can be maintained. The adhesive sheet with the separating film is successively provided with a base layer, an adhesive layer, and a separating film, and is obtained by co-extrusion of a material forming the adhesive layer and a material forming the base layer, and attachment of at least the material forming the adhesive layer in co-extrusion to the separating film, wherein the separating film comprises a stripping agent layer, and the content ratio of poly-functional organosilicone in organosilicone contained in the stripping agent layer is greater than 10%.

Description

Adhesive piece with spacer

The present invention relates to an adhesive sheet for a spacer.

The semiconductor wafer is manufactured in a large-diameter state, and after the front surface is patterned, the thickness of the wafer is usually thinned to about 100 μm to 600 μm by polishing the back surface, and then dicing into small pieces and then moved to installation steps.

In the step of polishing the back surface of the semiconductor wafer (back grinding step), an adhesive sheet is used to protect the pattern surface of the semiconductor wafer. Conventionally, as such an adhesive sheet, an adhesive sheet having an adhesive coated on a substrate is used, and for example, an adhesive layer coated with an acrylic adhesive on a substrate containing a polyethylene resin is proposed. sheet. (for example, Patent Document 1).

Usually, the spacer is placed on the adhesive sheet as a protective material for the adhesive layer, and is stored in the form of an adhesive sheet of the spacer. The adhesive sheet with the spacer is formed by co-extrusion because it can suppress the foreign matter from being mixed between the adhesive layer and the spacer, and the adhesive sheet having the smooth contact surface of the adhesive layer and the spacer can be obtained. A method of manufacturing a layer and an adhesive layer, and at least bonding the coextruded adhesive layer forming material to the separator in a molten state. However, the adhesive sheet of the spacer obtained in this manner is difficult to peel off due to welding of the spacer and the adhesive layer, and the handleability is lowered. Further, in the case of using such a problem that the separator is lightly peeled off, the handleability can be improved, but the adhesive force of the adhesive layer may be lowered. Thus, the adhesive sheet is bonded to at least the state in which the material forming the adhesive layer is melted. In the adhesive sheet of the spacer obtained by the spacer, it is difficult to balance the rationality and the moderate adhesion.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2007/116856

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide an adhesive sheet having a spacer which is excellent in rationality and which maintains an appropriate adhesive force after the separator is peeled off.

The adhesive sheet of the accessory of the present invention is provided with a substrate layer, an adhesive layer and a spacer in sequence. The adhesive sheet of the spacer of the present invention is formed by coextruding a material forming the adhesive layer with a material forming the substrate layer, and melting at least the co-extruded material forming the adhesive layer. Obtained by fitting the spacer. The separator includes a release agent layer, and the content ratio of the polyfunctional fluorenone in the fluorenone contained in the release agent layer is 10% or more.

In a preferred embodiment, the peeling force of the separator after hot pressing at 140 ° C is 4.0 N / 50 mm or less.

In a preferred embodiment, the adhesive layer comprises a polyolefin resin.

In a preferred embodiment, the polyolefin-based resin comprises an amorphous propylene-(1-butene) copolymer polymerized using a metallocene catalyst.

In a preferred embodiment, the adhesive sheet of the attachment of the present invention is semi-conductive. For wafer processing.

According to the present invention, it is possible to provide a spacer which adheres to the adhesive sheet and the spacer even in a state in which at least the material forming the adhesive layer is melted, and which maintains a moderate adhesive force after the spacer is peeled off. Adhesive piece of pieces. The adhesive sheet of such a spacer is particularly suitable as an adhesive sheet for semiconductor wafer processing.

A. The overall composition of the adhesive sheet with the spacer

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view showing an adhesive sheet of a spacer according to a preferred embodiment of the present invention. The adhesive sheet 100 with a spacer is provided with a base material layer 10, an adhesive layer 20, and a spacer 30 in this order. In the adhesive sheet 100 with a spacer, after the spacer 30 is peeled off, the base material layer 10 and the adhesive layer 20 are used as an adhesive sheet.

The thickness of the adhesive sheet 100 with a spacer is not particularly limited and can be set to any appropriate thickness. The thickness of the adhesive sheet after peeling off the spacer is preferably from 90 μm to 285 μm, more preferably from 105 μm to 225 μm, and still more preferably from 130 μm to 210 μm.

The thickness of the adhesive layer 20 is preferably from 20 μm to 100 μm, more preferably from 30 μm to 65 μm.

The thickness of the substrate layer 10 is preferably from 30 μm to 185 μm, more preferably from 65 μm to 175 μm.

The thickness of the spacer 30 is not particularly limited and can be set to any appropriate thickness. The thickness of the spacer 30 can be set, for example, from 25 μm to 250 μm.

The adhesive sheet of the accessory of the invention can be disposed on the side of the adhesive sheet As other layers. As the other layer, for example, a surface layer provided on the opposite side of the base material layer from the adhesive layer and capable of imparting heat resistance to the adhesive sheet can be cited.

The adhesive sheet of the spacer of the present invention preferably has an index of 85 or more, more preferably 90 or more. If the index is within such a range, the adhesive force required for the adhesive sheet is sufficiently obtained, for example, when used in the back grinding step of the semiconductor wafer, the semiconductor wafer can be sufficiently fixed in the polishing process. Details of the constituents of the adhesive layer are described below.

In addition, in the present specification, the index refers to the case where the adhesive sheet is aged after the adhesive sheet of the spacer of the spacer MRF38 (manufactured by Mitsubishi Plastics Co., Ltd.) which has been used previously is used, and the adhesive sheet is cured. Adhesion. Moreover, the adhesive force after curing of the adhesive sheet of the spacer means that the adhesive sheet of the spacer is cured at 50 ° C for 2 days, the separator is peeled off, and the semiconductor mirror wafer (manufactured by tantalum) is used as a test board. The adhesion was measured by the method according to JIS Z 0237 (2000) (adhesion conditions: 2 kg roller reciprocating once, peeling speed: 300 mm/min, peeling angle 180°).

B. spacer

The separator has a release agent layer, and the content ratio of the polyfunctional fluorenone in the fluorenone contained in the release agent layer is 10% or more. By using such a spacer, it is possible to obtain an adhesive layer and a base material layer which are formed by co-extrusion, and to bond the adhesive sheet with at least the material forming the adhesive layer. The spacer, the peeling force of the spacer is not increased, and has an excellent adhesive sheet. Moreover, since the adhesive layer and the spacer are further adhered to each other in a state in which at least the material forming the adhesive layer is melted, the foreign matter can be prevented from entering between the adhesive layer and the spacer.

Any appropriate release agent may be used for the release agent layer of the separator, and the content ratio of the polyfunctional fluorenone in the fluorenone contained in the release agent layer may be 10% or more. As the release agent, an anthrone-based release agent is preferably used. The anthrone contained in the release agent comprises a monofunctional anthrone (structural unit having 3 organic substituents), a difunctional anthrone (structural unit having 2 organic substituents), and a trifunctional anthrone (having 1) a structural unit of an organic substituent) and a tetrafunctional anthrone (a structural unit having no organic substituent). In the present specification, the polyfunctional fluorenone means a trifunctional or higher fluorenone.

The content ratio of the polyfunctional fluorenone in the fluorenone contained in the release agent layer of the separator is preferably from 10% to 60%, more preferably from 15% to 50%. When the content ratio of the polyfunctional fluorenone in the fluorenone contained in the release agent layer is within the above range, it is possible to obtain the adhesive sheet and the spacer even in a state in which at least the material forming the adhesive layer is melted. An adhesive sheet having a superiority and a spacer which maintains a moderate adhesion after the separator is peeled off. The content ratio of the polyfunctional fluorenone in the fluorenone contained in the release agent layer of the separator can be determined by analyzing the release agent layer of the separator using an ESCA (Electron Spectroscopy for Chemical Analysis).

When the content ratio of the polyfunctional fluorenone in the fluorenone in the release agent layer is 10% or more, the polyfunctional fluorenone hinders the bonding of the difunctional fluorenone with the material (resin) forming the adhesive layer. It functions as an easy peeling layer. Therefore, it is considered that the increase in the peeling force of the spacer can be suppressed in the present invention. It is considered that in the adhesive sheet of the spacer of the present invention, although the polyfunctional fluorenone is transferred onto the adhesive layer, since the amount of the fluorenone transferred is small, the adhesion of the adhesive layer can be suppressed from being lowered. . Furthermore, it is considered that the effects of the present invention are affected by The functional groups of the fluorenone have a large influence on the functionality, and the effect of the fluorenone having a specific substituent is small.

The content ratio of the polyfunctional fluorenone in the fluorenone in the release agent layer can be adjusted by any appropriate method, for example, by using the content ratio of the polyfunctional fluorenone in the fluorenone to be within the above range. The release agent or a release modifier containing a polyfunctional fluorenone is added to any release agent to adjust it.

The release agent layer may contain any other additives other than the above-mentioned release modifier, and examples thereof include an antioxidant, an ultraviolet absorber, and a viscosity modifier.

As the substrate of the separator, any appropriate substrate can be used, and examples thereof include a plastic film (for example, polyethylene terephthalate (PET), polyethylene, polypropylene), non-woven fabric, or paper.

The substrate of the spacer is preferably a substrate subjected to primer treatment. By using the substrate subjected to the primer treatment, an adhesive sheet having more excellent handleability can be obtained. The above primer treatment can be carried out by any appropriate means. Specifically, as the substrate to be subjected to the primer treatment, a substrate treated with a decane coupling agent can be used.

As the separator, a commercially available product can be used. Specifically, a Clean Separator HY series (more specifically, HY-S30, HY-S15, HY-TS11, HY-TS15) manufactured by Higashiyama Film Co., Ltd., or the like can be preferably used. .

The peeling force of the separator after pressing at 140 ° C is preferably 4.0 N / 50 mm or less, more preferably 3.0 N / 50 mm or less, further preferably 2.0 N / 50 mm or less. If the peeling force of the separator after pressing at 140 ° C is within the above range, An adhesive sheet having excellent peeling force and maintaining a moderate adhesive force after the separator is peeled off is obtained. Furthermore, in the present specification, the peeling force after pressing at 140 ° C refers to the peeling force of the separator measured after the adhesive sheet of the spacer is pressed at 140 ° C and placed at room temperature (peeling speed: 300) Mm/min, peeling angle: 180°). The pressing conditions at 140 ° C are as follows.

<Pressure conditions at 140 ° C>

The material of the substrate on which the adhesive sheet is formed is co-extruded with the material forming the adhesive layer, and at least the material for forming the adhesive layer is melted and the spacer for manufacturing (Mitsubishi Resin, MRF38, thickness 38 μm) ) Fit and make the adhesive sheet with the spacer. The adhesive sheet for the adhesive sheet was peeled off from the obtained adhesive sheet, and the adhesive layer of the adhesive sheet was bonded to the test spacer to prepare a test adhesive sheet.

The test adhesive sheet obtained was laminated in the order of stainless steel plate (SUS plate) / resin sheet / cushioning material / resin sheet / test adhesive sheet / resin sheet / cushioning material / resin sheet / stainless steel sheet, and then sandwiched by a press plate And using a press (manufactured by Toyo Seiki Co., Ltd., MINI TEST PRESS-10, board area: 250 mm × 250 mm), and holding it for 1 minute at a press surface temperature of 140 ° C and a press pressure of 5 MPa.

Further, MRN38 manufactured by Mitsubishi Plastics Co., Ltd. was used as a resin sheet (separator), and a rubber sheet (thickness: 1 mm, 130 mm × 160 mm) was used as a cushioning material.

C. Adhesive layer

The above adhesive layer may be composed of any suitable adhesive, for example, An adhesive containing a thermoplastic resin such as a polyolefin resin, an acrylic resin or a styrene resin. The pressure-sensitive adhesive layer preferably contains a polyolefin-based resin, and specific examples thereof include low-density polyethylene, ultra-low-density polyethylene, low-crystalline polypropylene, and amorphous propylene-(1-butene) copolymer. Polymer resin, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate-maleic anhydride copolymer, ethylene-glycidyl methacrylate copolymer, etc. Ethylene copolymer or polyolefin modified polymer, and the like. The adhesive layer more preferably contains an amorphous propylene-(1-butene) copolymer. By combining such an adhesive layer with the above-mentioned spacer to form an adhesive sheet, an adhesive sheet of a spacer having excellent practicability and maintaining a moderate adhesive force after the spacer is peeled off can be obtained. Further, in the case of such an adhesive layer, an adhesive sheet can be produced by co-extrusion with a base material layer, and an adhesive sheet can be obtained in a small number of steps without using an organic solvent. In the present specification, the term "amorphous" means a property which does not have a melting point as defined by crystallinity.

The above amorphous propylene-(1-butene) copolymer can be preferably obtained by polymerizing propylene with 1-butene using a metallocene catalyst. More specifically, the amorphous propylene-(1-butene) copolymer can be subjected to a polymerization step of polymerizing propylene and 1-butene using a metallocene catalyst, and a catalyst is used after the polymerization step. It is obtained by a subsequent processing step such as a residue removal step and a foreign matter removal step. The amorphous propylene-(1-butene) copolymer can be obtained in the form of a powder or a pellet after such a step. Examples of the metallocene catalyst include a homogeneous mixed catalyst containing a metallocene compound and an aluminoxane, and a metallocene supported on a fine particle carrier. Loading catalyst, etc.

The amorphous propylene-(1-butene) copolymer polymerized using a metallocene catalyst as described above exhibits a narrow molecular weight distribution. The molecular weight distribution (Mw/Mn) of the amorphous propylene-(1-butene) copolymer is preferably 3 or less, more preferably 2 or less, still more preferably 1.1 to 2, and particularly preferably 1.2 to 1.9. Since the amorphous propylene-(1-butene) copolymer having a narrow molecular weight distribution has a small amount of low molecular weight components, if such an amorphous propylene-(1-butene) copolymer is used, it can be prevented from being low. An adhesive sheet of a spacer which is oozing out of a molecular weight component and contaminated by an adhesive.

The content ratio of the structural unit derived from propylene in the amorphous propylene-(1-butene) copolymer is preferably from 80 mol% to 99 mol%, more preferably from 85 mol% to 99 mol%. Further preferably, it is 90% by mole to 99% by mole.

The content ratio of the structural unit derived from 1-butene in the amorphous propylene-(1-butene) copolymer is preferably from 1 mol% to 15 mol%, more preferably from 1 mol% to 10 Moer%. If it is in this range, the adhesive sheet of the attachment which is excellent in the balance of toughness and softness is acquired.

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

The weight average molecular weight (Mw) of the amorphous propylene-(1-butene) copolymer is preferably 200,000 or more, more preferably 200,000 to 500,000, still more preferably 200,000 to 300,000. When the weight average molecular weight (Mw) of the amorphous propylene-(1-butene) copolymer is within such a range, it can be obtained as compared with a usual styrene-based thermoplastic resin or acrylic thermoplastic resin (Mw is 100,000 or less). An adhesive sheet having a low molecular weight component and preventing contamination by adherends. Further, at the time of co-extrusion molding, the adhesive layer formed without processing can be obtained, and a moderate adhesive force can be obtained.

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, more preferably from 5 g/10 min to 30 g/10 min, further preferably 5 g/10 min to 20 g/10 min. When the melt flow rate of the amorphous propylene-(1-butene) copolymer is within such a range, an adhesive layer having a uniform thickness can be formed by co-extrusion without processing. The melt flow rate can be determined by a method in accordance with JIS K 7210.

The above amorphous propylene-(1-butene) copolymer may further contain structural units derived from other monomers within the range which does not impair 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, 3-methyl-1-pentene, and the like. Α-olefins and the like.

Preferably, the adhesive layer contains substantially no F ^- , Cl ^- , Br ^- , NO ₂ ^- , NO ₃ ^- , SO ₄ ^2- , Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , NH ₄ ⁺ . The reason for this is that contamination of the adherend by the ions can be prevented. When an adhesive sheet having such an adhesive layer is used for, for example, semiconductor wafer processing, disconnection or short circuit of the circuit does not occur. The adhesive layer containing no such ions can be obtained, for example, by polymerizing an amorphous propylene-(1-butene) copolymer contained in the adhesive layer using a metallocene catalyst solution as described above. In the solution polymerization using the metallocene catalyst, the amorphous propylene-(1-butene) copolymer can be purified by using a poor solvent different from the polymerization solvent to carry out precipitation separation (reprecipitation). An adhesive layer containing no such ions is obtained. In addition, in the present specification, "substantially free of F ^- , Cl ^- , Br ^- , NO ₂ ^- , NO ₃ ^- , SO ₄ ^2- , Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , NH ₄ ⁺ " means that the detection limit is not reached in standard ion chromatography analysis (for example, ion chromatography analysis using the trade name "DX-320" manufactured by Dionex Corporation, "DX-500"). Specifically, it means that F ^- , Cl ^- , Br ^- , NO ₂ ^- , NO ₃ ^- , SO ₄ ^2- and K ⁺ are respectively 0.49 μg or less with respect to 1 g of the adhesive layer, respectively, and Li ⁺ and Na ⁺ are respectively It is 0.20 μg or less, and Mg ²⁺ and Ca ²⁺ are respectively 0.97 μg or less, and NH ₄ ⁺ is 0.5 μg or less.

The storage modulus (G') of the above adhesive layer is preferably from 0.5 × 10 ⁶ Pa to 1.0 × 10 ⁸ Pa, more preferably from 0.8 × 10 ⁶ Pa to 3.0 × 10 ⁷ Pa. If the storage modulus (G') of the above-mentioned adhesive layer is within such a range, an adhesive sheet having a spacer which is excellent in rationality and which maintains a moderate adhesive force after peeling of the spacer can be obtained. Further, when the storage modulus (G') is within such a range, an adhesive sheet which can have sufficient adhesion to the adherend having irregularities on the surface and moderate peelability can be obtained. Moreover, when the adhesive sheet having the above-described adhesive layer having the storage modulus (G') is used for semiconductor wafer processing, it is possible to contribute to excellent polishing precision when polishing the back surface of the wafer. Furthermore, the storage modulus (G') in the present invention can be determined by dynamic viscoelasticity mapping.

In order to provide an adhesive sheet having a superiority and a spacer which maintains a moderate adhesive force after the separator is peeled off, the adhesive layer may further contain a crystalline polypropylene resin. The content ratio of the crystalline polypropylene-based resin can be set to any appropriate ratio depending on the desired adhesive force and the above-mentioned storage modulus. The content ratio of the crystalline polypropylene-based resin is preferably from 0% by weight to 50% by weight based on the total weight of the amorphous propylene-(1-butene) copolymer and the crystalline polypropylene-based resin. More preferably 0% by weight to 40% by weight %, further preferably 0% by weight to 30% by weight.

The crystalline polypropylene-based resin may be a homopolypropylene or a copolymer obtained from propylene and a monomer copolymerizable with propylene. Examples of the monomer copolymerizable with propylene include ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1. - an α-olefin such as pentene or the like.

The crystalline polypropylene-based resin is preferably obtained by polymerization using a metallocene catalyst similarly to the above amorphous propylene-(1-butene) copolymer. When the crystalline polypropylene-based resin obtained in the above manner is used, contamination of the adherend 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 can be determined by differential scanning calorimetry (DSC, differential scanning calorimetry) or X-ray diffraction.

The above-mentioned adhesive layer may further contain other components within the range which does not impair the effects of the present invention. Examples of the other component include an antioxidant, an ultraviolet absorber, a light stabilizer, a heat stabilizer, an antistatic agent, and the like. The types and amounts of other ingredients may be appropriately selected depending on the purpose.

D. substrate layer

The base material layer may be formed of any suitable material, and examples thereof include polyester (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate). Ester, etc., polyolefin (polyethylene, polypropylene, ethylene-propylene copolymer, etc.), polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymerization , polyvinyl acetate, polyamine, polyimine, cellulose, A fluorine resin, a polyether, a polystyrene resin (polystyrene or the like), a polycarbonate, a polyether oxime or the like. The base material layer preferably contains an ethylene-vinyl acetate copolymer.

The weight average molecular weight (Mw) of the above ethylene-vinyl acetate copolymer is preferably from 10,000 to 200,000, more preferably from 30,000 to 190,000. When the weight average molecular weight (Mw) of the ethylene-vinyl acetate copolymer is within such a range, the base material layer can be formed without processing at the time of co-extrusion molding.

The melt flow rate of the above ethylene-vinyl acetate copolymer at 190 ° C and 2.16 kgf is preferably 2 g/10 min to 20 g/10 min, more preferably 5 g/10 min to 15 g/10 min, and further It is preferably 7 g/10 min to 12 g/10 min. When the melt flow rate of the ethylene-vinyl acetate copolymer is within such a range, the base material layer can be formed by co-extrusion without processing.

The base material layer may further contain other components within the range which does not impair the effects of the present invention. As the other component, for example, the same components as those of the other components which can be included in the adhesive layer described in the above item C can be used.

E. Other layers

Examples of the other layer included in the adhesive sheet of the spacer of the present invention include a surface layer which can impart heat resistance to the adhesive sheet. By having this surface layer, it can also be preferably used as an adhesive sheet for semiconductor wafer processing for the heating step. As the surface layer, any suitable resin having heat resistance can be used, and a polypropylene resin is preferable. The above polypropylene-based resin is preferably obtained by polymerization using a metallocene catalyst. More specifically, the polypropylene-based resin can be subjected to a polymerization step in which a monomer composition containing propylene is polymerized by using a metallocene catalyst, and catalyst residue removal is carried out after the polymerization step. Obtained by a subsequent processing step such as a step, a foreign matter removing step, and the like. After the polypropylene resin is subjected to such a step, it can be obtained, for example, in the form of a powder or a pellet. Examples of the metallocene catalyst include those exemplified in the above item C.

The polypropylene-based resin polymerized using the metallocene catalyst in the above manner exhibits a narrow molecular weight distribution. Specifically, the molecular weight distribution (Mw/Mn) of the polypropylene resin is preferably 3 or less, more preferably 1.1 to 3, still more preferably 1.2 to 2.9. Since the polypropylene resin having a narrow molecular weight distribution has a small amount of a low molecular weight component, when such a polypropylene resin is used, it is possible to prevent bleeding of a low molecular weight component and obtain an adhesive sheet excellent in cleanability. Such an adhesive sheet can be preferably used, for example, for semiconductor wafer processing.

The weight average molecular weight (Mw) of the polypropylene resin is preferably 50,000 or more, more preferably 50,000 to 500,000, still more preferably 50,000 to 400,000. When the weight average molecular weight (Mw) of the polypropylene resin is within such a range, bleeding of the low molecular weight component can be prevented, and an adhesive sheet excellent in cleanability can be obtained. Such an adhesive sheet can be preferably used, for example, as an adhesive sheet for semiconductor wafer processing.

The above-mentioned polypropylene-based resin may further contain a structural unit derived from another monomer within the range which does not impair 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, 3-methyl-1-pentene, and the like. Α-olefins and the like. In the case of including a structural unit derived from another monomer, it may be a block copolymer or a random copolymer.

A commercially available product can be used for the above polypropylene resin. Specific examples of the polypropylene-based resin which is commercially available are exemplified by Japan Polypropylene Co., Ltd. The product names are "WINTEC" and "WELNEX" series.

The above surface layer may contain other components without departing from the scope of the invention. The other components may be the same as the other components exemplified in the above item C. The types and amounts of other ingredients may be appropriately selected depending on the purpose.

F. Method for manufacturing adhesive sheet with spacer

The method for manufacturing an adhesive sheet for a spacer of the present invention comprises the steps of: coextruding a material forming the above adhesive layer with a material forming the substrate layer, and at least causing the co-extruded to form an adhesive The step of bonding the adhesive sheet and the above-mentioned spacer in a state in which the material of the layer is melted. By co-extrusion molding, an adhesive sheet having good interlayer adhesion can be produced with a small number of steps and without using an organic solvent. Further, by adhering the adhesive sheet and the spacer in a state in which at least the co-extruded material forming the adhesive layer is melted, it is possible to suppress foreign matter from being mixed into the adhesive layer, and the adhesive layer is in contact with the spacer. smooth.

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

Specific examples of the co-extrusion molding include a method of supplying a material for forming an adhesive layer to at least one of at least two extruders connected to a mold, and supplying a material for forming a substrate layer. The other layer is melted and extruded, and at least the material forming the pressure-sensitive adhesive layer is melted in contact with the separator, and taken out by a contact roll forming method to form a laminate. When the adhesive sheet further has a surface layer capable of imparting heat resistance, The laminate can be formed by further adding an extruder and supplying a material forming the surface layer from the extruder. When squeezing, the closer the portion where the forming materials are joined, the closer to the die exit (mould lip). The reason for this is that it is not easy to cause a poor joining of the respective forming materials in the mold. Therefore, as the above mold, it is preferable to use a mold in the form of a multi-manifold. Further, in the case where the merging failure occurs, an appearance defect such as merging unevenness occurs, and specifically, a wavy appearance unevenness is generated between the extruded adhesive layer and the substrate layer, which is not preferable. Further, the merging failure is caused by, for example, a large difference in fluidity (melt viscosity) between the different types of forming materials in the mold, and a large difference in the shear rate of the material forming the layers, so that a multi-manifold form is used. The mold is expanded in scope for different types of forming materials having poor fluidity compared to other forms (for example, in the form of a feed module). The type of screw used for the melt of each of the formed materials may be uniaxial or biaxial. There are also more than 3 extruders. Further, when an adhesive sheet having a two-layer structure (base material layer + adhesive layer) is produced by using three or more extruders, the same forming material can be supplied to two or more adjacent extruders. For example, in the case of using three extruders, the same forming material can be supplied to two adjacent extruders.

The bonding can be carried out by contacting the coextruded material forming the substrate layer with the material forming the adhesive layer by means of any suitable mechanism. As the contact mechanism, for example, a contact roller or the like can be mentioned.

The forming temperature in the above co-extrusion molding is preferably from 160 ° C to 220 ° C, more preferably from 170 ° C to 200 ° C. If it is in this range, the adhesive layer forming material after extrusion can be in a molten state, and it is possible to suppress the foreign matter from being mixed into the adhesive layer of the obtained adhesive sheet, and to make the surface of the adhesive layer in contact with the spacer flat. slip. Moreover, when it is such a range, it is excellent in shaping|molding stability.

The difference between the material forming the adhesive layer and the material forming the substrate layer at a temperature of 180 ° C and a shear rate of 100 sec ^-1 (the material forming the adhesive layer - the material forming the substrate layer) Preferably, it is -150 Pa‧s~600 Pa‧s, more preferably -100 Pa‧s~550 Pa‧s, and further preferably -50 Pa‧s~500 Pa‧s. If it is in such a range, the material which forms the adhesive layer and the material which forms the base material layer are similar in fluidity in a mold, and can prevent the occurrence of a merge defect. Further, the shear viscosity can be measured using a twin 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, the test and evaluation methods in the examples and the like are as follows. Also, parts mean parts by weight.

[Example 1]

As a material for forming a surface layer capable of imparting heat resistance, a polypropylene resin obtained by polymerizing a metallocene catalyst (manufactured by Japan Polypropylene Co., Ltd., trade name "WELNEX: RFGV4A"; melting point: 130 ° C, softening point is used. 120 ° C, Mw / Mn = 2.9).

As a material for forming the base material layer, an ethylene-vinyl acetate copolymer (manufactured by DU PONT-MITSUI Co., Ltd., trade name "EVAFLEX P-1007") was used.

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

100 parts of the material for forming the surface layer, 100 parts of the material for forming the substrate layer, and 100 parts of the above-mentioned material for forming the adhesive layer were placed in each extruder to perform T-die melt co-extrusion (mold temperature: 180 ° C). The spacer 1 (manufactured by Higashiyama Film Co., Ltd., HY-S30, thickness: 38 μm) was attached to the adhesive layer of the laminate of the surface layer/substrate layer/adhesive layer which was co-extruded from the mold by a contact roll. Adhesive sheet of surface layer (thickness 30 μm) / substrate layer (thickness 130 μm) / adhesive layer (thickness 45 μm) / spacer spacer. Furthermore, the thickness of the surface layer, the substrate layer and the adhesive layer is controlled by the shape of the T-die outlet.

[Embodiment 2]

An adhesive sheet of a spacer was obtained in the same manner as in Example 1 except that the spacer 2 (manufactured by Higashiyama Film Co., Ltd., HY-TS11, thickness: 75 μm) was used instead of the spacer 1.

[Example 3]

An adhesive sheet of a spacer was obtained in the same manner as in Example 1 except that the spacer 3 (manufactured by Higashiyama Film Co., Ltd., HY-TS15, thickness: 75 μm) was used instead of the spacer 1.

(Comparative Example 1)

An adhesive sheet of a spacer was obtained in the same manner as in Example 1 except that the spacer C1 (manufactured by Mitsubishi Plastics Co., Ltd., MRF38, thickness: 38 μm) was used instead of the spacer 1.

(Comparative Example 2)

An adhesive sheet of a spacer was obtained in the same manner as in Example 1 except that the spacer C2 (manufactured by Mitsubishi Plastics Co., Ltd., MRE 38, thickness: 38 μm) was used instead of the spacer 1.

(Comparative Example 3)

An adhesive sheet of a spacer was obtained in the same manner as in Example 1 except that the spacer C3 (manufactured by Mitsubishi Plastics Co., Ltd., MRN 38, thickness: 38 μm) was used instead of the spacer 1.

[Evaluation of the partition]

The content of the fluorenone in the release agent layers of the separators 1 to 3 and C1 used in Examples 1 to 3 and Comparative Example 1 was measured. Further, the peeling force after pressing at 140 ° C of the adhesive sheets of the spacers of Examples 1 to 3 and Comparative Examples 1 to 3 was evaluated by the following method.

(1) Anthrone content of the release agent layer

The release agent layer of each spacer was analyzed by ESCA (X-ray photoelectron spectroscopy apparatus), and the content of anthrone in the release agent layer, difunctional fluorenone, and polyfunctional fluorenone (trione of trifunctional or higher) were measured. The content ratio of anthrone in the release agent layer. The polyfunctional fluorenone content in the release agent layer was calculated from the measured fluorenone content and the content ratio of the polyfunctional fluorenone. The content of anthrone in the release agent layer, the content of the polyfunctional fluorenone, the content of the difunctional fluorenone, and the polyfunctional fluorenone are shown in Table 1.

(2) Peel test after hot pressing at 140 °C

The adhesive sheet obtained from Comparative Example 1 was peeled off from the spacer C1, and the adhesive layer of the adhesive sheet was bonded to the spacers 1 to 3 or the spacers C1 to C3 to prepare a peeling force test for bonding at 140 ° C. sheet.

The test adhesive sheet to be obtained is a stainless steel plate (SUS plate) / resin sheet / buffer After the material/resin sheet/evaluation adhesive sheet/resin sheet/cushion material/resin sheet/stainless steel sheet is laminated, it is sandwiched by a press plate, and a press machine (manufactured by Toyo Seiki Co., Ltd., MINI TEST PRESS-10, board surface) is used. Area: 250 mm × 250 mm) for pressing. MRN38 manufactured by Mitsubishi Plastics Co., Ltd. was used as a resin sheet (separator), and a rubber sheet (thickness: 1 mm, 130 mm × 160 mm) was used as a cushioning material. The test adhesive sheet was kept at a pressing plate surface temperature of 140 ° C and a pressing pressure of 5 MPa for 1 minute. Next, the adhesive sheet was allowed to stand at room temperature, and the peeling force of the spacer of the adhesive sheet (peeling speed: 300 mm/min, peeling angle: 180°) was measured. The measured peeling force is shown in Table 1.

[Evaluation]

The adhesive sheets obtained in the examples and the comparative examples were subjected to the following evaluations. The results are shown in Table 1.

(1) Peel force of the spacer

The peeling force of the separator in the obtained adhesive sheet was measured (peeling speed: 300 mm/min, peeling angle: 180°). If the peeling force is 2.0 N/50 mm or less, it is excellent in rationality.

(2) Si wafer adhesion

After the obtained adhesive sheet was aged at 50 ° C for 2 days, the separator attached to the adhesive layer was peeled off by a method in accordance with JIS Z 0237 (2000) (adhesion conditions: 2 kg roller reciprocating once, peeling speed) : 300 mm/min, peeling angle 180°) The adhesion of the adhesive layer to the mirror surface of the 4 Å semiconductor wafer was measured.

(3) followed by the index

The Si wafer adhesion force of Comparative Example 1 was set to 100, and the adhesion indexes of the adhesive sheets of Examples 1 to 3 and Comparative Examples 1 to 3 were obtained. If the index is subsequently 85 or more, it has sufficient adhesion to be used as, for example, an adhesive sheet for a back grinding step of a semiconductor wafer.

That is, after the adhesive sheets of Examples 1 to 3 were obtained by bonding the spacers in a state in which the adhesive layer forming material was melted, the spacers were excellent in rationality. Further, the adhesive layer after peeling of the spacer of the adhesive sheets of Examples 1 to 3 maintained excellent adhesion.

A TEM (Transmission Electron Microscopy) image of the separator peeled off from the adhesive sheet of Example 1 is shown in Fig. 2 . In the adhesive sheet of Example 1, the layer in which the adhesive layer and the release agent layer of the separator were condensed was not confirmed. Further, after the adhesive sheet of the self-attached spacer was peeled off from the spacer, the contact faces of the spacer and the adhesive sheet were observed, and as a result, the damage of the adhesive layer was not confirmed.

On the other hand, the separator of the adhesive sheet of Comparative Example 1 had a low peeling force and was inferior in handleability. The TEM image of the spacer side of the adhesive sheet of the spacer of Comparative Example 1 after peeling off the spacer is shown in Fig. 3, and the TEM image on the side of the adhesive layer is shown in Fig. 4. As shown in Fig. 3, on the side of the separator of the adhesive sheet of Comparative Example 1, a layer in which the ketone of the adhesive layer and the release agent layer was condensed was confirmed. It was confirmed on the adhesive sheet of the spacer of Comparative Example 1 that the layer formed by the condensation of the above-mentioned adhesive layer and the release agent layer as an interface, the cohesive layer cohesive failure, and the spacer and the adhesive sheet were formed in this form. Stripped. It is considered that in the adhesive sheet of Comparative Example 1, the handleability is lowered due to the coagulation of Si between the adhesive layer and the release agent layer. On the other hand, as shown in FIG. 4, the adhesive layer of the adhesive sheet of Comparative Example 1 did not leave a layer in which the adhesive layer and the fluorenone were condensed, and only the adhesive layer was confirmed. Therefore, the adhesive sheet of Comparative Example 1 was considered to maintain the adhesive force.

Comparative Examples 2 and 3 using a lightly peelable spacer have superiority. Although it has an adhesive force that can be used as an adhesive sheet, the adhesive force is lowered.

[Industrial availability]

The adhesive sheet of the spacer of the present invention can be preferably used, for example, for the protection of a workpiece (semiconductor wafer or the like) at the time of manufacture of a semiconductor device.

10‧‧‧Substrate layer

20‧‧‧Adhesive layer

30‧‧‧Parts

100‧‧‧Adhesive sheets with spacers

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view showing an adhesive sheet of a spacer according to a preferred embodiment of the present invention.

Figure 2 is a TEM image of the spacer peeled from the adhesive of the septum of Example 1.

Fig. 3 is a TEM image of a cross-sectional side section of the adhesive sheet of the spacer of Comparative Example 1 after the separator was peeled off.

Fig. 4 is a TEM image of an adhesive sheet side cross section of the adhesive sheet of the spacer of Comparative Example 1 after the separator was peeled off.

10‧‧‧Substrate layer

20‧‧‧Adhesive layer

30‧‧‧Parts

100‧‧‧Adhesive sheets with spacers

Claims (7)

An adhesive sheet with a spacer, which is provided with a substrate layer, an adhesive layer and a spacer in sequence, and which is formed by coextruding a material forming the adhesive layer with a material forming the substrate layer, and at least The co-extruded material forming the adhesive layer is obtained by laminating with the spacer, and the spacer comprises a release agent layer, and the polyfunctional fluorenone in the fluorenone contained in the release agent layer The content ratio is 10% or more. The adhesive sheet of the appendage of claim 1, wherein the peeling force of the spacer after hot pressing at 140 ° C is 4.0 N / 50 mm or less. An adhesive sheet according to the appendage of claim 1 or 2, wherein the adhesive layer comprises a polyolefin resin. The adhesive sheet of the appendage of claim 3, wherein the polyolefin-based resin comprises an amorphous propylene-(1-butene) copolymer polymerized using a metallocene catalyst. An adhesive sheet according to the appendage of claim 1 or 2, which is used for semiconductor wafer processing. An adhesive sheet according to the appendage of claim 3, which is used for processing semiconductor wafers. The adhesive sheet of the appendage of claim 4 is for semiconductor wafer processing.