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Process for Improvement of Smoothness of an Alumina Substrate Used

IP.com Disclosure Number: IPCOM000091507D
Original Publication Date: 1968-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Aboaf, JA: AUTHOR [+2]

Abstract

This process is for improving the smoothness of an alumina substrate which is used in the manufacture of integrated circuits. The smoothness of the substrate used in the integrated circuit environment is important because, for example, the sheet resistance of sputtered resistors is affected by the degree of roughness of the alumina substrate.

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Process for Improvement of Smoothness of an Alumina Substrate Used

This process is for improving the smoothness of an alumina substrate which is used in the manufacture of integrated circuits. The smoothness of the substrate used in the integrated circuit environment is important because, for example, the sheet resistance of sputtered resistors is affected by the degree of roughness of the alumina substrate.

The problems resulting from surface roughness are solved by applying a glaze to the surface of the substrate. Such glaze must, however, be compatible with the characteristics of the substrate and with subsequent treatment steps.

After deposition of a film of Al(2)O(3) by vapor deposition at low temperature, most Pits in the alumina substrate are filled up or covered and surface smoothness is improved. The film, after a heat treatment, is crystalline alumina and matches the coefficient of expansion of the substrate. As it is not possible to deposit layers two microns thick without cracking, the following process is used. Deposition is effected by a low-temperature, vapor deposition process of an Al(2)O(3) thin film approximately 5000 Angstroms thick on an alumina substrate. This is followed by heat treating the substrate at a temperature of over 800 degrees C for three hours with subsequent slow cooling. These two steps are repeated until a layer two microns thick is obtained.

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