Repairs to Complex Hybrid Circuits - Their Effect on Reliability

Abstract

The anticipated performance of manufactured devices is at present based on long-term use history of similar items. The hybrid microelectronic circuit is of recent vintage and its history is relatively short. To counter this short history, predictions have been cautious and in-process environmental screening and testing have been used to achieve performance. It has been proposed that the reliability performance of a hybrid circuit can be achieved, or enhanced, when no repairs are made to the device during assembly and subsequent testing. To investigate the validity of this theory, the proper combination of factors must be made available detailed knowledge of the circuit history during assembly, screening, and testing history of the performance in the system level effort and finally, but most important, the complete history of the device's use by the ultimate customer in his environment. These factors were available for a large group of circuits, of five different designs. The conclusions reached are significant in that they show that repairs can be made without affecting the hybrid circuit performance or reliability.