The Demand and Practical Approach for 100x Test Compression

How much better does test have to be in order to satisfy industry needs in the near future? If 10times tester cycle compression is sufficient in many cases, why should test continue advances toward 100times compression or more? Advances in manufacturing and design methodologies are pushing test capability to require additional compression, quality, and efficiency, making significant improvements not only desirable but mandatory. With current deep submicron technologies, test cycles have increased more than l0times. This is not only due to larger designs but also additional pattern types are necessary to detect newer defect mechanisms. At the same time, these bigger designs are moving to more modular/hierarchical design methodologies. Consequently, fewer test signals are desired from blocks and more compression is necessary such that it can be used for 3times or more reduction in test signals. Compounding these requirements is an upcoming move to multi-site production tests where several to dozens of ICs are tested in parallel. Test will need another 3-5times fewer 10 pins to enable testers to test many chips together. In addition, memory device populations and area are huge; they require not only better test methods but improved techniques to reduce the memory test logic and routing. These circumstances all add up to significant requirements that test provide over l00times combined reduction of test time/data, block test signals, and test pins