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Browse Prior Art Database

Structure for Enhancing Thermal Nucleation of Semiconductor Devices

IP.com Disclosure Number: IPCOM000051389D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Frieser, RG: AUTHOR [+3]

Abstract

A sintered layer of glass or ceramic on the back side of a solder-bonded chip immersed in a cooling liquid provides a nucleating surface that significantly improves cooling efficiency.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 88% of the total text.

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Structure for Enhancing Thermal Nucleation of Semiconductor Devices

A sintered layer of glass or ceramic on the back side of a solder-bonded chip immersed in a cooling liquid provides a nucleating surface that significantly improves cooling efficiency.

To insure proper and continued operation of a device chip, the heat generated during the operation of the chip must be removed. A technique for removing heat is to immerse the chip in a suitable coolant. This approach works efficiently only when the back side of the chip facing the coolant has sufficient thermal nucleation sites to insure continuous nucleating boiling at the required temperature. A smooth, polished silicon surface does not have an adequate number of nucleation sites. A roughening of the surface by sand blasting or etching increases the number of nucleation sites. However, these techniques and others increase the probability of causing defects in the crystalline structure which could cause failure of the device over long operating periods.

In this structure an adequately nucleating surface is generated on the back side of the chip by depositing a sintered layer of glass or ceramic. A low melting glass combined with terpineol to form a paste can be applied to the back side of the chip, dried at approximately 200 degrees C, and then fired for 3 hours at 500 degrees C. The resulting surfa very porous and nucleates very well in perfluorohexane. Another approach for providing a nucleating surface is to p...