Browse Prior Art Database

Polyimide or KTFR in Kerf During Dicing/Chip Sawing

IP.com Disclosure Number: IPCOM000043502D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Lindholm, A: AUTHOR [+2]

Abstract

Previous dicing/chip sawing methods have permitted the saw blade to cut through bare silicon. This results in a ragged chip edge of quartz and silicon. Cracks in turn tend to propagate from this ragged edge, and chips must therefore be scrapped. Polyimide or KTFR in the kerf during dicing/chip sawing and higher level manufacturing processes produces fewer edge chips and cracks. This results in higher yields, better productivity and higher reliability at no additional cost. The last polyimide mask in the process is redesigned to accommodate a space approximately 10-50 mm wide outside the edge seal on the chip. This last mask also allows for the kerf area to be covered with polyimide. The 10-50 mm space permits the hermetic edge seal to remain undisturbed by any dicing or polyimide in the kerf defects.

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Polyimide or KTFR in Kerf During Dicing/Chip Sawing

Previous dicing/chip sawing methods have permitted the saw blade to cut through bare silicon. This results in a ragged chip edge of quartz and silicon. Cracks in turn tend to propagate from this ragged edge, and chips must therefore be scrapped. Polyimide or KTFR in the kerf during dicing/chip sawing and higher level manufacturing processes produces fewer edge chips and cracks. This results in higher yields, better productivity and higher reliability at no additional cost. The last polyimide mask in the process is redesigned to accommodate a space approximately 10-50 mm wide outside the edge seal on the chip. This last mask also allows for the kerf area to be covered with polyimide. The 10-50 mm space permits the hermetic edge seal to remain undisturbed by any dicing or polyimide in the kerf defects. The present invention requires only a change in the polyimide mask design; no additional processes or tooling is required. The polyimide in the kerf creates a cushion through which the dicing saw blade will cut. The resultant chip has a straight clean edge and is free from edge fractures, chips and edge cracking (Fig. 1). These conditions give higher productivity, better quality and yield and a more reliable product. The polyimide along the chip edge after dicing gives additional protection during handling in chip spirals, tracks, testers and other tools. Similarly, by redesigning the photo mask a layer of KTFR can...