STMicroelectronics claims world’s first contactless wafer test
STMicroelectronics, a European chip company, claims to have produced the first wafer tested wirelessly without the use of contact probes. Electromagnetic wafer sort (EMWS) technology, which is also the last stage of wafer fabrication prior to assembly and test of packaged ICs, was applied to a wafer of RFID (Radio Frequency Identification) ICs.
By testing the die wirelessly it can remove the need for dedicated test pads and reduce die area in most applications. The new EMWS technology comes from an R&D project called UTAMCIC (UHF TAG Antenna Magnetically Coupled to Integrated Circuit), led by Alberto Pagani, Giovanni Girlando and Alessandro Finocchiaro from STMicroelectronics, and Professor Giuseppe Palmisano from the University of Catania, which won a prestigious ‘Sesames Award’ in the ‘Production & Test’ category at Cartes and IDentification 2010 in Paris in December 2010.
“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, because the RF circuits, anticollision protocol and embedded antenna are tested under the same conditions they will operate under in the customer’s application, it will significantly enhance quality and reliability.”
Individual dice contain tiny antenna’s while the ATE supplies power to communicate with the dice via electromagnetic waves. From this point the number of test pads on the die are reduced, significantly shrinking the die size. Probes still need to supply power to test high-power products but ST’s novel technique enables the company full contactless testing of low-power circuits.