Dicing Tape Performance in a Plasma Dicing Environment

Abstract

The traditional method of dicing semiconductor wafers into individual die is accomplished using diamond saws or more recently, using various laser based approaches. Both technologies require the wafer to be frame mounted on dicing tape. These procedures all introduce an element of heat and in some cases water for cooling purposes, but they do not expose dicing tape to the unique conditions within high vacuum plasma. This program of work investigates how the properties of both dicing tape and its adhesive are affected when exposed to the environment of a plasma dicing process used in the semiconductor industry.A preliminary fitness test, utilizing an aggressive exothermic etching regime, was used to establish the compatibility of a range of standard LINTEC Adwill dicing tapes. This is, essentially, a measure of base film thermal conductivity, and how quickly some of the low molecular weight volatile organic components of base film and adhesive materials are ‘out-gassed’. See Fig. 3Polyvinyl Chloride (PVC) tapes performed less well than Polyethylene terephthalate (PET) tapes and some of the Polyolefin (PO) tapes exhibited the greatest resilience.A design of experiments, to measure changes in tensile strength, elongation and adhesive properties, was conducted to assess the effect of plasma dicing on PO and PVC tape. Findings demonstrated that exposure to an SF 6 plasma or full plasma dicing process directly impacted the tape elongation and tensile strength properties of PO and PVC samples. However, as the stretch required for damage free die pick is in the range 1-10%, results showed that plasma dicing does not impact the necessary elongation performance of the tape.Further tests employing a die pick-up force measurement system to compare saw diced die with plasma diced die proved the feasibility of this technology demonstrating that pick-up force measured on plasma diced dies is comparable with saw diced dies.