The significant density and performance improvement of VLSI ( Very Large Scale Integration ) devices has brought with it new and major problems in device design manufacturing and testing resulting in an exponential increase in both device design time and device test program development time .

VLSI（超大规模集成电路）器件在密度和性能方面的飞速发展，给器件的设计、制造和 测试提出了新的挑战，导致器件的设计时阃和测试 程序的开发 时间成指数增长。