Voltage contrast electron beam testing experiments on very large scale integrated chip packaging substrates

Test and inspection are key in reducing costs and increasing reliability of multichip hybrid modules. Increasing very large scale integrated chip packaging densities requiring finer linewidths and more substrate interconnection networks are taxing the probing resolution, throughput, and reliability of conventional mechanical probe test systems. Voltage contrast electron beam test technology was seen as an attractive alternative for high‐throughput, noncontact testing of unpopulated packaging substrates and high‐density printed wiring boards. A conventional scanning electron microscope was modified by adding large‐field vector deflection, a large‐field secondary analyzer, beam blanking, an electron flood gun, and a computer control system, thereby providing the primary test functions required for opens and shorts testing: net charging, net voltage measurement, and global charge removal. Successful substrate test results are shown along with data which highlight potential failure mechanisms such as substrat...