US 5,304,842 A · Dissimilar adhesive die attach for semiconductor devices

Abstract

A semiconductor assembly comprises a semiconductor die which is attached by a carrier material to a lead frame. The carrier material is coated on the die side with one type of adhesive and on the lead frame side with a different adhesive. The lead frame has a small surface area to connect to the carrier material, while the semiconductor die has a large surface area to connect to the carrier material. As used with one inventive embodiment, the adhesive between the die and the carrier softens at a low temperature preventing the die from cracking at elevated temperatures. The adhesive on the lead frame side of the carrier material softens at a higher temperature than the adhesive of the die side of the adhesive, thereby firmly connecting the lead frame having a small surface area to the carrier.

Claims20

Dependent claims

A semiconductor assembly, comprising:

a) a semiconductor die having a major surface with bond pads located thereon;
b) a lead frame having lead fingers, each lead finger having an end which terminates proximally to said die;
c) a carrier material having first and second major surfaces;
d) a first adhesive material which attaches said first major surface of said carrier material with said lead frame;
e) a second adhesive material which attaches said second major surface of said carrier material with said die,
wherein after the assembly is assembled said second adhesive softens at a lower temperature than said first adhesive, said softening of said second adhesive relieving stress between said die and said second adhesive, and said first adhesive providing a solid attachment at said second adhesive softening temperature between said lead frame and said carrier material.

3 more elements

Dependencies are inferred from the claim text.

Dissimilar adhesive die attach for semiconductor devices

Life of this patent

Dissimilar adhesive die attach for semiconductor devices

Life of this patent

Abstract

Claims20