ABSTRACT
Short-flow electrical test structures are extremely useful for determining the effect of certain process conditions on process defectivity. Thus, the test structure can be used to test the result of changes made to a process condition specifically to reduce the number of defects. Because they can be processed in a relatively short time, short-flow structures can also be used as realtime process-monitoring and process-control tools. The gate oxide dielectric is the heart of a metal oxide semiconductor (MOS) or complementary MOS (CMOS) integrated circuit. Gate oxide integrity tests can vary widely in terms of the specific capacitor structures and the criteria for evaluation. Examples of various types of capacitor structures are: areas/perimeters; blocks or stripes (edge effects); with or without field oxide; and with or without sidewall oxide. There are many contamination and defect sources within an entire wafer fabrication process.
