Browse Prior Art Database

Improvements to Module Packaging

IP.com Disclosure Number: IPCOM000041310D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Marlard, P: AUTHOR [+3]

Abstract

The present disclosure provides optimum curing conditions for polyimide used as insulating material in the fabrication of metallized ceramic substrates. After the ceramic substrate has been metallized according to a predetermined pattern, e.g., by evaporating a chrome-copper-chrome metallurgy over the whole surface and applying standard photoresist steps to provide the desired pattern, it may be desirable to coat the exposed surface with a polymeric material, such as a polyimide. The latter step is commonly practiced as long as an additional metal interconnection scheme is needed in addition to the chrome-copper-chrome first level, the polyimide acting as an insulating medium between the two metal layers. The following process aids the final curing of such polyimide layer, avoiding the extra steps of baking and stripping. 1.

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Improvements to Module Packaging

The present disclosure provides optimum curing conditions for polyimide used as insulating material in the fabrication of metallized ceramic substrates. After the ceramic substrate has been metallized according to a predetermined pattern, e.g., by evaporating a chrome-copper-chrome metallurgy over the whole surface and applying standard photoresist steps to provide the desired pattern, it may be desirable to coat the exposed surface with a polymeric material, such as a polyimide. The latter step is commonly practiced as long as an additional metal interconnection scheme is needed in addition to the chrome-copper-chrome first level, the polyimide acting as an insulating medium between the two metal layers. The following process aids the final curing of such polyimide layer, avoiding the extra steps of baking and stripping. 1. After the polyimide layer has been dried by a standard erratic polyimide personalize by photolithography and etch. 2. Strip the remaining portions of the photoresist material. 3. Cure the substrate in one step at 240 C for 30 minutes. Normally curing polyimide requires three steps, including the drying step at 105 C, the two other temperatures being about 210 C and 360 C. It has been recognized that imidization starts at 180OEC and is final at 240OEC. The selection of this temperature not only assures a complete imidization but also avoids the critical stripping steps which were previously necessary. Stripping...