Dissimilar adhesive die attach for semiconductor devices
First Claim
1. 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.
1 Assignment
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Accused Products
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.
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Citations
20 Claims
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1. A semiconductor assembly, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 20)
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11. An encapsulated semiconductor memory device, comprising:
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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. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification