STMicroelectronics develops first wafer using contactless testing

The new testing technology uses a tiny antenna to communicate with test equipment using electromagnetic waves

12/16/2011

STMicroelectronics reported that it has developed the first semiconductor wafer that can be tested with electromagnetic waves instead of contacts. The development could result in higher yields, shorter testing times, and lower cost for chips.

In addition, contactless testing allows RF circuits to be tested under conditions that are close to the real application conditions, according to ST.

The new ElectroMagnetic Wafer Sort (EMWS) technology is used in the last stage of wafer fabrication before assembly and test of the final packaged products. With EMWS, individual dice contain a tiny antenna and the automated test equipment supplies power and communicates with the dice via electromagnetic waves. This approach reduces the number of test pads on the die, significantly shrinking the die size.

Probes are still required to supply power to test high-power products, but ST’s technique enables fully contactless testing of low-power circuits.

“This breakthrough in testing technology demonstrates ST’s commitment to our zero-failure policy and especially benefits customers using our low-power RF circuits,” said Alberto Pagani, test R&D and competitive intelligence, a developer of the new technology. Contactless testing improves test coverage and reduces the test cycle time because it enables high testing parallelism to be achieved in contactless mode, according to STMicroelectronics. It also increases yield by eliminating the pad damage that occasionally occurs during standard contact testing.