Browse Prior Art Database

POLYIMIDE PLANARIZATION

IP.com Disclosure Number: IPCOM000005665D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2001-Oct-24
Document File: 2 page(s) / 77K

Publishing Venue

Motorola

Related People

J. Foerstner: AUTHOR [+2]

Abstract

As part of our ongoing metal backend development work a photoresist problem was noted, which appeared to relate to the lack of planarity associated with the polyimide interlayer structure used.

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MOTOROLA Technical Developments Volume 7 October 1987

POLYIMIDE PLANARIZATION

by J. Foerstner and D. Rodgers

As part of our ongoing metal backend development work a photoresist problem was noted, which appeared to relate to the lack of planarity associated with the polyimide interlayer structure used.

The nature of the problems noted was as follows:

1) Photo mask failure over the 2nd metal pad edge during 2nd metal pattern and etch. This was the result of photoresist thinning due to depth of adjacent metal contour.

2) Lack of dimensional control at the 2nd via photomasking step (small via vs large via) due to varying thickness photoresist over a non-planar underlying structure. (Photoresist due to its high solids con- tent and low viscosity planarizes very well).

3) A trade-off of dimensional control vs photoresist scumming at the 3rd metal photooperation again due to the planarizing effects of photoresist over a polyimide background with step heights on the order of 3 microns.

   All of these problems were a direct result of the lack of planarity of our existing polyimide structure. Once the problem had been identified, the need to address our customer delivery schedules dictated a3 phase develop- ment approach.

Phase I - Was a quick fix that could be implemented immediately using existing technology and ma- terials with a minimum inherent risk factor, and acceptable and reproducible results. The solu- tion of choice was a triple high speed spin version of our ex...