Scan-based testing: the only practical solution for testing ASIC/consumer products

Over the last 2-3 years, there has been a major change in the IC industry from being predominantly "functional-based testing" to being predominantly "scan-based testing" (for new design starts). The question has now changed to: "can we completely avoid functional testing?" The same trends that are driving companies toward scan-based testing will also drive them to completely avoid functional-based testing. The advantages of structural testing cannot be fully exploited unless at-speed functional testing is avoided. The move away from functional testing will happen in stages. Some companies are already avoiding functional test for some test insertions - but not all. For example, some products are currently tested with scan-based, reduced pincount testing at wafer level - but still require full pincount, scan+functional testing at package test.