Iddq testing for CMOS VLSI

It is little more than 15-years since the idea of Iddq testing was first proposed. Many semiconductor companies now consider Iddq testing as an integral part of the overall testing for all IC's. This paper describes the present status of Iddq testing along with the essential items and necessary data related to Iddq testing. As part of the introduction, a historical background and discussion is given on why this test method has drawn attention. A section on physical defects with in-depth discussion and examples is used to illustrate why a test method outside the voltage environment is required. Data with additional information from case studies is used to explain the effectiveness of Iddq testing. In Section IV, design issues, design styles, Iddq test vector generation and simulation methods are discussed. The concern of whether Iddq testing will remain useful in deep submicron technologies is addressed (Section V). The use of Iddq testing for reliability screening is described (Section VI). The current measurement methods for Iddq testing are given (Section VII) followed by comments on the economics of Iddq testing (Section VIII). In Section IX pointers to some recent research are given and finally, concluding remarks are given in Section X.