Environmentally Hardening IC Die Previously Assembled in Plastic Packages through Die Removal, Bond Pad Replating and Reassembly into Hermetic Packages

Abstract

ABSTRACT Many integrated circuits (ICs) will operate well above their maximum rated temperature of +70°C or +125°C, but are often not packaged appropriately to reliably endure temperatures above +150C. Specifically, the original gold or copper bonds on the aluminum die bond pads are prone to Kirkendall or Horsting voiding, particularly at temperatures greater than +150°C. Also the mold compounds used in plastic packaging for IC assembly can degrade at these elevated temperatures. In some cases, commercial demand for higher temperature reliability can justify a separate offering of ICs assembled in hermetic, ceramic packages from the original component manufacturer (OCM). However, in most cases, the market demand is deemed insufficient. Global Circuit Innovations (GCI) has developed a high-yielding process, which can remove a semiconductor die (i.e., computer chip) from a plastic package, remove the original bond wires and/or ball bonds, plate the aluminum die bond pads with Electroless Nickel, Electroless Palladium, and Immersion Gold (ENEPIG), and then reassemble the now improved semiconductor die into a hermetic, ceramic package. Device Extraction, ENEPIG die bond pad plating and Repackaging (DEER) provides an improved die bond pad surface such that works well with either gold or aluminum bond wires in applications up to +250°C without mechanical or electrical connectivity degradation. GCI routinely exposes sample devices to +250°C bakes with 100% post bake yields so as to continuously ensure that any device processed with the DEER technology will reliably perform in high-temperature environments. Although the oil and gas industry has already expressed significant interest in the DEER process, with excellent lifetest and production application results demonstrating dramatically increased component lifetimes at elevated temperatures, this technology can also be leveraged for any application exposing ICs to harsh environments. Not only is the high-temperature reliability dramatically increased, but also the new hermetic, ceramic package protects the IC from a variety of elements and environments (i.e., corrosives and moisture).