Contamination of Chip Surfaces by Particles During Destructive Physical Analysis of Integrated Circuit Devices

Abstract

The process of accessing a component or chip in a hermetically sealed, integrated circuit device by destructively cracking through the package is a major source of particulate contamination of the chip surface. If a polyimide layer exists on the chip surface and is subsequently removed by peeling, electrostatic charging during the peeling process results in an even greater particulate concentration both on the chip and on the side of the polyimide which had been adhering to the chip. The particles can be observed with a microscope and are characterized by X-ray Photoelectron Spectroscopy to be either lead oxide or aluminum oxide. They resist complete removal by such methods as blowing with an anti-static Freon duster or brushing away. The amount of contamination by the particles can be decreased but not completely eliminated by a modified cracking method.