Orthogonal Defect Solutions for Silicon Crystal Growth and Wafer Processing

摘要

The silicon industry is a maturing one. Mature industries have, or should have, different concrns than young industries. One of the features which characterized the silicon industry in its youth is that of defect engineering. Defect issues such as the control of oxygen precipitation and intrinsic point defect related micro-defects have been at the centre of this enterprise for many years. These are very difficult and complex problems from both a scientific and an engineering point of view. They are, importantly, highly coupled problems. Because of the complexity inherent in some of these problems, more often that not solutions to issues presented by such problems have produced rather highly tuned measures specific to certain applications. It has also produced armies of application engineers and commodity teams whose job is, among other things, to manage this complexity and the problems of material specification in such an environment. But this is not the way a mature industry behaves. For a variety of reasons, a mature industry strives for solutions which are as generic as possible; a mature industry strives to reduce the inherent costs of highly engineered specific solutions. A mature industry tries, where possible, to sidestep complexity; a mature industry strives for solutions to specific problems which are orthogonal to the solutions for other problems. In other words, it needs solutions which cannot create problems elsewhere in the complex environment in which it operates. We have by no means yet reached full orthogonality of defect solutions for silicon, but we approaching it. And indeed some of the issues with silicon wafers simply do not lend themselves to such principles of orthogonality. But we must strive to apply them where they are possible. This paper discusses two such orthogonal solutions to the immensely important problems of oxygen precipitation and micro-defect control in silicon wafers: the Magic Denuded Zone (MDZ) and Perfect Silicon.