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Borosilicate Glass for Use in High Density Packages

IP.com Disclosure Number: IPCOM000077428D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Langston, PR: AUTHOR [+2]

Abstract

High-density and high-performance packages require that the dielectric be a material of smooth surface finish, low-dielectric constant and good thermal stability. The natural choice, of course, is a glass which, however, needs the support of a ceramic such as aluminum oxide. The later requirement, in addition demands that the glass be compatible with the ceramic. In addition, the glass should be: 1) Chemically resistant to acids and 85% RH at 85 degrees C. 2) Sinterable to non-porous, bubble-free, clear and smooth films at 800 degrees C. 3) Devoid of microheterogenous regions such as phase separation, divitrification, etc.

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Borosilicate Glass for Use in High Density Packages

High-density and high-performance packages require that the dielectric be a material of smooth surface finish, low-dielectric constant and good thermal stability. The natural choice, of course, is a glass which, however, needs the support of a ceramic such as aluminum oxide. The later requirement, in addition demands that the glass be compatible with the ceramic. In addition, the glass should be:
1) Chemically resistant to acids and 85% RH at 85 degrees C.
2) Sinterable to non-porous, bubble-free, clear and

smooth films at 800 degrees C.
3) Devoid of microheterogenous regions such as phase

separation, divitrification, etc.

A borosilicate glass of the following composition and properties essentially satisfies all of the above requirements, and results in thermal mismatch camber of less than one mil for four layers of glass (8 mils): SiO(2) 64.5 B(2)O(3) 19.8 Na(2)O 3.0 K(2)O 4.6 CaO 1.0 Al(2)O(3) 7.1. Thermal expansion coefficient, R.T.-300 degrees C: 51 x 10/-7// degrees C Thermal expansion coefficient, R.T.- Set Pt.: 60 x 10/-7// degrees C Softening temperature: 747 degrees C Annealing temperature: 520 degrees C Firing temperature: 800 degrees C.

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