Testability Exploration of 3-D RAMs and CAMs

Three-dimensional (3-D) integration is an emerging integrated circuit technology. It offers many advantages over the 2-D integration. However, testing 3-D chips is a very challenging job. The testing of a 3-D chip includes the testing for known good die (KGD) and the testing of stacked 3-D chip. This paper analyzes the test complexities of 3-D random access memories (RAMs) and content addressable memories (CAMs) in the phase of testing of stacked 3-D ICs with functional faults. Analysis results show that the 3-D CAMs and RAMs can be tested with lower test complexity than the 2-D ones. Furthermore, simple design-for-testability (DFT) methods are proposed to reduce the test complexity of 3-D RAMs and CAMs further.