Checking an integrated circuit using pre-production simulation and post-production tests

摘要

A silicon device 136, such as an integrated circuit, is simulated as an instrumented logic design 120 before it is manufactured. The logic design is evaluated using a simulator 124 provided with test instructions 126 and cycle breakpoints 114. The simulation values at the cycle breakpoints are accumulated in a checksum unit 130 to form a cumulative simulation record. The silicon device is then manufactured. The manufactured device is tested using the same test instructions 126 and breakpoints 114 used in the simulation, and a checksum unit 140 calculates a cumulative silicon record. A comparator 144 compares the simulation and silicon cumulative records to indicate a fault in the manufactured component. The testing therefore compares simulated and measured results. In one embodiment, the silicon device may be a chip in a computer and the comparison of simulated and measured results may be part of a self test of the computer. For this purpose, the breakpoints 114 and test instructions 126 used in the pre-manufacture simulation are stored in the computer. In addition, the checksum unit 140 may provide an input to a random number generator 146 which allows the computer to generate random numbers without e.g. an alpha source or keystroke logger.