LEAD FRAME MATERIAL FOR LARGE-CAPACITY DRAM AND LARGE-CAPACITY DRAM

摘要

PURPOSE: To obtain a lead frame material by which the coefficient of thermal expansion of an epoxy resin is matched well with that of an Si chip, whose yield rate is enhanced and whose costs are lowered by a method wherein the lead frame material is formed of an Fe-Ni alloy whose Ni content is specific. ;CONSTITUTION: An Fe-Ni alloy whose Ni content is at 33 to 39wt.% is rolled to be a lead frame material, and a stamping and working process is executed. After that, a die bonding process in which an Si chip for a DRAM is bonded to an island and a wire bonding process in which leads are bonded to the Si chip are executed. The die bonding process is executed by adopting an Ag-paste bonding method so as to be heated to 150 to 200°C, and the wire bonding process is executed by adopting an Au-wire thermocompression-bonding method so as to be heated to 250 to 300°C. A lead frame which has finished the processes is formed as a package after an epoxy resin has been filled and heated up to 400°C, the leads are cut and bent, and the DRAM is completed.;COPYRIGHT: (C)1995,JPO