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Method of Preventing Damage to Integrated Circuit Chips during Wafer Dicing

IP.com Disclosure Number: IPCOM000108332D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 75K

Publishing Venue

IBM

Related People

Tam, A: AUTHOR [+3]

Abstract

The laser-based method described in this article cuts softly through the layers. This laser prework step is followed by standard dicing which is non-damaging.

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This is the abbreviated version, containing approximately 53% of the total text.

Method of Preventing Damage to Integrated Circuit Chips during Wafer Dicing

       The laser-based method described in this article cuts
softly through the layers.  This laser prework step is followed by
standard dicing which is non-damaging.

      In IC (integrated circuit) production, the chips are finally
diced after completion of the various processing steps.  The standard
approach is dicing the silicon wafer with a diamond blade.  In high-
performance circuitry using copper as a conductor and a polymer as a
dielectric, problems arise if the copper/polymer interfacial strength
is not very high.  During dicing, the blade first cuts through the
copper/polymer layers before cutting the silicon wafer.

      It has been observed in copper/polyimide systems that
polyimide/ polyimide or polyimide/copper delamination (microcracks)
may occur next to the dicing area.  Such microcracks are caused by
tensile and shearing forces the dicing blade produces during dicing.
The microcracks in copper/polyimide wiring structures in the
interconnection layers may impair the reliability and lead to
long-term failure of the chip in the field, because of moisture
absorption in the cracks or partly separated polyimide/polyimide
interfaces, and eventual copper corrosion.

      The described method uses pulsed high-power laser ablation
which is a photochemical/photothermal process requiring nanoseconds
for its implementation (potential lasers being Nd:YAG, excimer, CO2).
...