Use of a heat-resistant adhesive sheet for wafer level package fabrication

摘要

The present invention is intended to solve the following problems with a method for fabricating a substrateless semiconductor package using an adhesive tape as a temporary fixing supporter. A chip can be displaced from a specified position by pressure during resin encapsulation because the chip is not properly held by the adhesive tape. If such displacement occurs, the relative positional relationship between the chip and an interconnect to be connected to a specified position in a subsequent wiring step also changes by the displacement of the chip from the specified position. Another problem is that if adhesive deposits occur during peeling of the adhesive tape and the surface of a package is contaminated with the adhesive deposits, adhesive components left on the surface of the chip can inhibit connection between the interconnect and the chip in a subsequent wiring step. Yet another problem is that gas generated from the adhesive layer or a part of the adhesive eluted from the adhesive layer under heat generated during use of the device also can contaminate the surfaces of the chips. To solve these problems, the present invention provides a heat-resistant adhesive sheet for semiconductor device fabrication that is attached to a substrateless semiconductor chip when the chip is encapsulated with resin. The adhesive sheet includes a base material layer and an adhesive layer. The adhesive layer contains a rubber component and an epoxy resin component. The proportion of the rubber component in an organic substance in the adhesive is in the range of 20 to 60 wt%.