JP4820113B2 - Adhesive sheet and method for producing the same - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive sheet and a method for manufacturing the same, and in particular, in a process of manufacturing various semiconductors, dicing of electronic components such as a semiconductor wafer having a pattern formed thereon or a semiconductor device part encapsulated with a resin into a unit chip or a device. The present invention relates to an adhesive sheet for adhering and fixing to the back surface of the electronic component when (cutting / dividing) and a manufacturing method thereof.

  Since the blade used when dicing the electronic component for each unit chip or device becomes worse each time it is cut, the base of the adhesive sheet that is adhered and fixed to the back surface of the electronic component as in Patent Document 1, for example. There is a method of dressing a blade with abrasive grains simultaneously with cutting of an electronic component by blending abrasive grains with a material sheet. Further, as another method, for example, as in Patent Document 2, there is a method of blending abrasive grains with an adhesive or laminating an abrasive layer between a base sheet and an adhesive.

In Patent Document 1 (a method of blending abrasive grains in a base sheet), it is difficult to process the base material, and it is difficult to obtain a sheet having a uniform thickness. In the method of blending abrasive grains with the adhesive (Patent Document 2), the adhesive strength of the adhesive is reduced, chipping occurs during dicing (a phenomenon that a chipped wafer is chipped), and the adhesive layer is soft enough. A polishing effect was not obtained. In the method of laminating an abrasive layer between a base sheet and an adhesive (Patent Document 2), the adhesiveness with the adhesive is inferior, and adhesive residue (residue remains) on the electronic component when the adhesive sheet is peeled off It was.
Japanese Patent Publication No. 2-24871 Japanese Patent Publication No.2-24872

  The problem to be solved by the present invention is that even if the blade is dressed with abrasive grains simultaneously with the cutting of the electronic component, there is no adhesive residue on the electronic component, and the blade is clogged while maintaining the holding force on the electronic component. It is providing the adhesive sheet which prevented chipping by preventing, and its manufacturing method.

  The invention of the present application is an abrasive layer containing abrasive grains having a Mohs hardness of 6 to 9 and an average particle diameter of 50 μm or less, a synthetic resin layer laminated on both surfaces, and a synthetic resin. The pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer on one side or both sides of the layer.

  According to another invention, an abrasive layer containing abrasive grains having a Mohs hardness of 6 to 9 and an average grain size of 50 μm or less is coated and dried on a synthetic resin layer for the back surface. This is a pressure-sensitive adhesive sheet manufacturing method in which a synthetic resin layer for a surface is laminated on an abrasive layer after drying, and a pressure-sensitive adhesive layer is applied to one side or both sides of the synthetic resin layer on both sides.

  According to the present invention, even when the blade is polished with abrasive grains during dicing, there is no adhesive residue on the electronic component, and while maintaining the holding force on the electronic component, chipping is prevented by preventing the blade from being clogged. Can be prevented.

  According to another invention, even when the blade is polished with abrasive grains during dicing, there is no adhesive residue on the electronic component, and the blade can be prevented from being clogged while maintaining the holding force on the electronic component. An adhesive sheet capable of preventing chipping can be produced.

  In the present invention, the abrasive layer and the synthetic resin layer laminated on both sides thereof are formed because the abrasive layer and the pressure-sensitive adhesive layer are in direct contact with each other even if the blade is dressed with abrasive grains simultaneously with the cutting of the electronic component. This is because no adhesive residue is generated on the electronic component and abrasive grains are blended in the adhesive, so that the holding force on the electronic component is maintained and chipping is prevented.

  The Mohs hardness of the abrasive compounded in the abrasive layer is 6 to 9 with a 10-step Mohs hardness meter. If the Mohs hardness is less than 6, the blade cannot be polished sufficiently and the Mohs hardness is greater than 9. This is because the abrasion amount of the blade is large and the synthetic resin film is burnt due to the heat generated during dicing and is fused to the chuck table. As the abrasive grains that can be employed in the present invention, specifically, there are Green Carborundum, Corundum, White Alundum, Boron Carbide, etc., as abrasive grains with Mohs hardness 9, and Quartz etc. as abrasive grains with Mohs hardness 7 Abrasive grains having a Mohs hardness of 6 include iron oxide, and abrasive grains having a width of Mohs hardness of 7 to 9 include emery and may be a mixture thereof. When the pressure-sensitive adhesive layer is an ultraviolet curable pressure-sensitive adhesive, it is necessary to allow the ultraviolet rays that pass through the abrasive layer to reach the pressure-sensitive adhesive layer. The reason why the average grain size of the abrasive grains is 50 μm or less is that when the average grain size tends to be large, a blade having a width of 35 μm usually has a large resistance, which causes breakage of the blade. Is 30 μm or less. Further, if the average particle size of the abrasive grains tends to be small, the effect of polishing tends to be difficult to obtain, and therefore it is preferably 0.5 μm or more, more preferably 1 μm or more.

  As the binder for the abrasive layer, there are known resin binders such as polyurethane resin, polyester resin, polyimide resin, and epoxy resin, and as a solvent to be used for manufacturing the abrasive layer, there are methyl ethyl ketone, toluene, and ethyl acetate. You may add an isocyanate type hardening | curing agent to the liquid mixture of a resin binder and a solvent. The thickness of the abrasive grain layer is preferably larger than the grain diameter of the abrasive grain so that the surface of the abrasive grain layer is not uneven, and specifically, it is preferably 1 μm or more and 100 μm or less.

  When the content of the abrasive grains in the abrasive layer is too small, the effect of polishing cannot be obtained, and when the content is too large, the adhesiveness with the substrate is deteriorated, so 10 to 95 wt% is preferable.

  The synthetic resin that forms the synthetic resin layer may be a conventionally known synthetic resin that is used as the base material of the pressure-sensitive adhesive sheet. Specifically, polyvinyl chloride, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-ethyl There are acrylate copolymers, polyethylene, polypropylene, ethylene-acrylic acid copolymers, ionomers, and the like, and ionomers are preferable in the case of suppressing generation of cutting waste during dicing.

  The ionomer generally refers to a metal-oriented resin of ethylene-methacrylic acid copolymer. In addition, the ionomer used in the synthetic resin layer in the present invention is an ethylene-acrylic acid copolymer system or ethylene. -The ternary body which polymerized acrylic acid ester, methacrylic acid ester, etc. as methacrylic acid and ethylene-acrylic acid as a 3rd component, and also the metal orientation resin of the further multi-component copolymer is contained. That is, it refers to a metal orientation resin of a multi-component copolymer having a carboxyl group in a broad sense. Specifically, ethylene-acrylic acid ionomer, ethylene-methacrylic acid ionomer, ethylene-methacrylic acid-propyl methacrylate ionomer, ethylene-methacrylic acid-butyl methacrylate ionomer, ethylene-methacrylic acid-hexyl methacrylate ionomer, ethylene -Acrylic acid-acrylic acid 2-methylpropyl ionomer, ethylene-methacrylic acid-acrylic acid 2-methylpropyl ionomer, ethylene-methacrylic acid-methacrylic acid 2-methylbutyl ionomer, ethylene-methacrylic acid-methacrylic acid 2- Examples include ethyl butyl ionomer and ethylene-methacrylic acid-methacrylic acid 2-methylhexyl ionomer.

  Examples of metal ions that crosslink the carboxyl group of the ionomer include sodium ions and zinc ions. In order to prevent adverse effects on the semiconductor wafer, ionomers using zinc ions are preferred.

  In the case where the pressure-sensitive adhesive layer is an ultraviolet curable pressure-sensitive adhesive, it is necessary to allow the ultraviolet rays irradiated through the synthetic resin layer to reach the pressure-sensitive adhesive layer. Therefore, a synthetic resin that transmits ultraviolet rays is preferable.

  As the pressure-sensitive adhesive layer in the present invention, a conventional pressure-sensitive pressure sensitive adhesive, an ultraviolet curable pressure sensitive pressure sensitive adhesive, a radiation curable pressure sensitive pressure sensitive adhesive, or the like can be used.

  The thickness of the pressure-sensitive adhesive layer may be a value adopted as a pressure-sensitive adhesive sheet, preferably 5 to 50 μm, more preferably 5 to 40 μm.

  The method for producing a pressure-sensitive adhesive sheet according to another invention comprises applying and drying an abrasive layer containing abrasive grains having a Mohs hardness of 6 to 9 on a 10-stage Mohs hardness meter on a synthetic resin layer for the back surface, This is a pressure-sensitive adhesive sheet manufacturing method in which a synthetic resin layer for a surface is laminated on an abrasive layer after drying, and a pressure-sensitive adhesive layer is applied to one side or both sides of the synthetic resin layer on both sides.

  Hereinafter, the present invention will be described in detail with reference to Table 1 with examples and comparative examples.

  The pressure-sensitive adhesive sheet in Example 1 is formed by sequentially forming a pressure-sensitive adhesive layer, a synthetic resin layer for the back surface, an abrasive layer, and a synthetic resin layer for the surface.

This pressure-sensitive adhesive sheet was formed in the next step.
A paint prepared by dispersing a green carborundum having an average particle size of 10 μm in a mixed liquid of a polyurethane resin binder and a solvent (methyl ethyl ketone) and adding an isocyanate curing agent (green carborundum: resin binder = 50 wt%: 50 wt%) was applied to the surface of PET (polyethylene terephthalate sheet) having a thickness of 25 μm, dried to evaporate the solvent, and the resin binder was cured to form an abrasive layer having a thickness of 20 μm. This abrasive grain layer and PE (polyethylene sheet) having a thickness of 40 μm were laminated with a pressure-sensitive adhesive to obtain a substrate. A pressure sensitive adhesive was applied to the obtained base material PET by 10 μm by transfer coating to obtain an adhesive sheet.

  This adhesive sheet was evaluated under the following dicing conditions.

  As a dicing apparatus, DAD341 manufactured by DISCO was used. The blade used was NBC-ZH2050-27HEEE made by DISCO. The rotation speed of the blade was 30000 rpm, and the feed rate was 40 mm / sec. The water temperature of the cooling water was 25 ° C., and the amount of water was 1.5 liters / minute.

  As an electronic component to be diced, a 0.4 inch thick silicon wafer having a thickness of 0.4 mm was used, the dicing pattern was 1 mm × 1 mm, and the amount of cut into the adhesive sheet was 50 μm.

  In Table 1, “Number of dicing lines” means that the silicon wafer after dicing is observed from the back side with an ultra-deep form observation microscope (VK-8500, manufactured by Keyence Corporation) at a magnification of 200 times, and the maximum chipping width is 50 μm. It is the number of lines that have been diced until they occur. The case of 20000 or more is a pass.

  In Table 1, “fused” means “existing” when the silicon wafer was diced under the above conditions and the back of the synthetic resin film was fused to the chuck table, and “no” when it was not seen. did.

  In Example 1, a dicing tape having dicing properties was obtained. The examples and comparative examples described below are the same as the present examples unless otherwise specified.

  The pressure-sensitive adhesive sheet of Example 2 is the same as Example 1 except that the synthetic resin layer is an ionomer.

  Example 3 is the same as Example 1 except that the grain size of the abrasive grains was 0.3 μm. When the grain size of the abrasive grains was small, the number of dicing lines was small, but the number was acceptable.

  Comparative Example 1 was the same as Example 1 except that the abrasive grains were apatite with a Mohs hardness of 5. When the Mohs hardness of the abrasive grains was low, the number of dicing lines was small and chipping was likely to occur.

  Comparative Example 2 is the same as Example 1 except that the abrasive grains are diamonds having a Mohs hardness of 10. When the Mohs hardness of the abrasive grains was high, the back surface of the synthetic resin film was fused to the chuck table, the chuck table was damaged, and the process was interrupted.

  Comparative Example 3 is the same as Example 1 except that the grain size of the abrasive grains is 60 μm. When the grain size of the abrasive grains was large, the blade was damaged and the number of dicing lines was reduced.

The pressure-sensitive adhesive sheet and the manufacturing method thereof according to the present application are used when dicing an electronic component, and are particularly used in a process of dicing a semiconductor wafer.

Claims (6)

An abrasive layer containing abrasive grains having a Mohs hardness of 6 to 9 and an average particle size of 0.5 μm to 50 μm, a synthetic resin layer laminated on both surfaces thereof, and a synthetic resin An adhesive sheet having an adhesive layer on one or both sides of the layer. The pressure-sensitive adhesive sheet according to claim 1 , wherein the synthetic resin forming the synthetic resin layer is an ionomer. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein a blending ratio of abrasive grains in the abrasive grain layer is 10 to 95 wt%. It is an object for electronic components , The adhesive sheet as described in any one of Claims 1-3 . The pressure-sensitive adhesive sheet according to claim 4 , which is used for electronic component dicing. On the synthetic resin layer for the back surface, an abrasive layer containing abrasive grains having a Mohs hardness of 6 to 9 and an average grain size of 0.5 μm or more and 50 μm or less with a 10-step Mohs hardness meter is applied and dried. A method for producing a pressure-sensitive adhesive sheet comprising laminating a synthetic resin layer for a surface on an abrasive layer after drying, and applying a pressure-sensitive adhesive layer to one side or both sides of the synthetic resin layer on both sides.