DEK has developed processes for depositing silver epoxy and B-stage adhesives for die attach applications, for higher throughput and repeatability as well as enhanced control over deposit characteristics including total thickness variation (TTV).
 
The process for B-stage epoxy deposition allows application of die attach adhesive at the wafer level, at high rates of throughput. This streamlines package assembly and also allows OEMs to outsource this process to a wafer specialist. The process can deposit a part-cured adhesive layer of nominal thickness 50 micron, with TTV less than ±5 micron, across the back side of the wafer.
 
For attaching singulated die to a lead-frame or bond pad, the process replaces dispensing to deposit silver-loaded wet epoxy ahead of die attach. Many hundreds of deposits can be made simultaneously, so epoxy deposition can match the speed of die placement. Die placement rates are 40,000 units/hr., with SMT pick-and-place technology.
 
“Mass imaging delivers the throughput, uniformity and repeatability that commercial producers of advanced semiconductor packages need in order to economically meet market demands for quality and price,” said Clive Ashmore, Global Applied Process Engineer at DEK. “For die attach using B-stage or wet epoxy adhesives, our mass imaging processes outgun legacy techniques in every respect, to deliver a more highly optimized, faster, more repeatable and more cost-effective solution.”
 
 
DEK, www.dek.com