Method of mounting an i.c. chip on a substrate

Abstract

The method of mounting on a substrate an integrated circuit (I.C.) chip having flexible beam leads bonded to input/output (I/O) terminals on the active face of the I.C. chip. The substrate has a chip pad and outer lead (OL) pads associated with the chip pad on a surface of the substrate. Preforms of a fiber glass web coated with a thermosetting plastic are cut to a size that substantially conforms to that of the chip pad. The substrate and the chip pad are heated to a first temperature which the preform will adhere to the chip site, the preform is placed on the chip pad, and the active face of the I.C. chip is pressed into the preform. The temperature of the substrate, preform and chip, are then raised to a second temperature higher than the first to partially cure the thermoplastic material and to encapsulate the active face of the I.C. chip and portions of the leads proximate the chip in the thermoplastic material of the preform. The I.C. chip is oriented so that its leads overlie the OL pads, and its leads are thermocompression bonded to the OL pads. The substrate is then heated to a third temperature higher than the second to finally cure the thermosetting plastic.