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Semiconductor Device Package Having a Substrate With a Coefficient of Expansion Matching Silicon

IP.com Disclosure Number: IPCOM000089813D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Howard, RT: AUTHOR

Abstract

Thermal mismatch of silicon semiconductor material and conventional substrate materials, such as alumina, causes thermally induced fatigue problems in solder-mounted flip-chart integrated circuits. The stress generated by the thermal expansion mismatch limits the component life and integration level in the semiconductors. For example, the coefficient of expansion of silicon is approximately 2.4 x 10/-6/, while ceramic material is 7 x 10/-6/.

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Semiconductor Device Package Having a Substrate With a Coefficient of Expansion Matching Silicon

Thermal mismatch of silicon semiconductor material and conventional substrate materials, such as alumina, causes thermally induced fatigue problems in solder-mounted flip-chart integrated circuits. The stress generated by the thermal expansion mismatch limits the component life and integration level in the semiconductors. For example, the coefficient of expansion of silicon is approximately 2.4 x 10/-6/, while ceramic material is 7 x 10/-6/.

In this package, the substrate 10 is a laminate of an organic polymerized material, such as polyimide, epoxy, or the like, and a prepreg formed of a commercially available aramid fiber identified as KEVLAR 29 or 49*. This unique combination of an organic polymer resin material, having a relatively high coefficient of expansion greater than silicon, and the KEVLAR fiber, having a negative or a very low coefficient of expansion, results in a composite structure with a thermal coefficient of expansion of the silicon devices 12 mounted on substrate 10. Matching of the thermal coefficient of expansion of the substrate 10 and the devices 12 eliminates thermally induced fatigue failures of the interconnections 14, resulting in increases in life and reliability of the electronic circuits fabricated from this material.

The precise coefficient of expansion of substrate 10 is influenced by a number of factors, for example, the relative amoun...