Development of packaging system for mounting beam lead integrated chip circuit on lead frame is discussed. Process for fabricating large scale integration circuits is described. Diagrams illustrating method of construction are included

Kennedy, B. W.

English

NASA Technical Reports Server

July 172	 B72-10329 
I NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce now technology derived from the U.S. space pro g ram. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
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be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Packaging Concept for LSI Beam Lead Integrated Circuits 
The problem: 
In today's packaging methods of large scale integrated 
(LSI) circuits, the circuit package has become the limit-
ing factor on system size. Previously, metal, plastic, or 
ceramic packages were prefabricated, and the integrated 
circuit chips were mounted inside the package by solder-
ing or epoxy bonding. 
The solution: 
A packaging system has been devised utilizing a lead 
frame to mount a beam lead integrated circuit chip. 
After molding, the lead frame becomes a part of the 
package. One size lead frame can be used for chips in the 
range of 0.127 x 0.127 cm (50x50 mils). Formerly, a 
new package design was required for different chip sizes. 
How it's done: 
A beam lead chip is mounted on a lead frame as 
shown in the figure. The art work is layed out on a 
pattern generator on a one to one scale of the lead 
frame. The photographic pattern is then exposed on 
0.0127 cm (0.005 in) thick Kovar plate. The Kovar 
plate is then etched and the lead frame is gold plated to a 
thickness of 0.00127 cm (0.0005 in). The beam lead 
chip is then positioned on the lead frame and thermo. 
compression bonding of the gold beam leads to the lead 
frame is accomplished. The beam lead chip, now sup-
ported in the lead frame by the thermo.compression 
bonds, can be readily probed for electrical testing. It is 
then potted in place with a high purity space grade 
silicone rubber. The lead frame is then masked off using 
Teflon tape to prevent the rubber from coming in contact 
with the remaining part of the leads. It is then placed 
into a molding machine and molded using a low expan-
sion and high thermal conductivity material, such as 
resin epoxy. The beam lead chip is now encapsulated 
into a finished package as shown in the figure. The 
complete packaging can be fabricated in a few minutes 
at a cost of a few cents per package.
Lead Frame 
lj 
Epoxy/ Interconnects \Silicone 
Resin	 Rubber 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&TS-TU 
Huntsville, Alabama 35812 
Reference: B72-10329
(continued overleaf) 
This document was prepared under the sponsorship of the National
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Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19720000328 2020-03-17T03:29:04+00:00Z
Patent status:
	
. 
This invention is owned by NASA, and a patent 
application has been flied. Royalty-free, non-exclusive 
licenses for its commercial use will be granted by NASA. 
Inquiries concerning license rights should be made to: 
Patent Counsel 
Marshall Space Flight Center 
Code A & TS-PAT 
Huntsville, Alabama 35812 
Source: B. W. Kennedy
Marshall Space Flight Center
(MFS-21374) 
B72-10329	 Category 07


Packaging concept for LSI beam lead integrated circuits

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