Chapter 2 - Integrated Circuit Test Basics

Abstract

This chapter presents the integrated circuit test basics. Computer-aided design (CAD) computer software is used to design and test ICs. This software is sophisticated and highly specialized. Previously designed cells are stored in the CAD design library. Each cell is specifically tailored in relation to the other cells to perform the intended function. The designer uses these cells to design each layer of the circuit. In deposition, the conducting layers, metal, epitaxial silicon (epi), metal silicides, and insulating material such as silicon dioxide and related materials, are deposited on the wafer. This process is critical because lack of uniformity in the thickness of deposited layers creates reliability problems. In diffusion, the doping agent is introduced to the semiconductor substrate. A precondition for diffusion is the existence of a concentration gradient that facilitates the uniform distribution of atoms in the solid. Testing dies on a wafer or on a packaged die is done by sophisticated application-specific computers known as “automated test equipment” (ATE). ATEs may be different in physical appearance or software design, but they all have the same purpose. It has been found that the most common tests are propagation delay and rise and fall times.