7 October 2022
Aehr enhances FOX-P wafer-level test & burn-in systems for SiC and GaN
Semiconductor test and reliability qualification equipment supplier Aehr Test Systems of Fremont, CA, USA has released two new enhancements for its FOX-P family of wafer-level test and burn-in systems – the FOX Bipolar Voltage Channel Module (BVCM) and Very High Voltage Channel Module (VHVCM) options – which enable advanced capabilities for silicon carbide (SiC) and gallium nitride (GaN) power semiconductors.
SiC power devices and modules are being widely adopted in the drive train used in electric vehicles (EVs) as well as on-board and off-board electric vehicle chargers. GaN-based semiconductors are at the early stages of their application usage, but are expected to grow significantly in their use in a wide range of power conversion applications including photovoltaic, industrial and other electrification infrastructure applications. The new capabilities allow silicon carbide and gallium nitride semiconductor manufacturers more flexibility to address a wider variety of stress and burn-in conditions to address their engineering qualification and production needs in FOX-P multi-wafer test and burn-in systems. These options are available with new system shipments or for upgrades of previously shipped FOX-P systems, with first shipments planned with typical 12-16 week lead times.
The Bipolar Voltage Channel Module (BVCM) provides a wide range of bipolar voltage programmability from +40V to –30V applied to the gate for positive high-temperature gate bias (HTGB) or negative HTGB testing. The BVCM can supply gate bias voltage to more than 3000 die per wafer while capable of monitoring individual die performance. The BVCM, in combination with Aehr’s proprietary WaferPak full-wafer contactors, are said to deliver a unique capability benefitting power silicon carbide diodes and MOSFETs and both E-mode and D-mode gallium nitride power MOSFET manufacturers. Enabling these tests are particularly essential in threshold voltage (VTH) and gate oxide stabilization and screening.
The Very High Voltage Channel Module (VHVCM) enables customers to perform high-temperature reverse bias (HTRB) testing on wafers at up to 2000V on MOSFETs and diodes and measure individual device leakage current. Aehr’s proprietary WaferPak contactor implements arcing mitigation technology to alleviate high-voltage arcing on the wafer, especially with fine-pitch die-to-die geometries. A full-wafer HTRB stress test on silicon carbide or gallium nitride technology can be applied up to 2000V in a single touchdown.
The modularity of the FOX-P system offers the ability to configure solutions to provide advanced test capabilities for their power electronic device wafers. These advanced capabilities enable manufacturers to ship products with higher reliability and parametric stability necessitated by an electric vehicle’s traction inverters and on-board chargers. Test and burn-in at wafer level ensures better control of yield loss and improved product reliability. Ultimately, consumers benefit from higher reliability and lower costs.
“Aehr has engaged with a significant number of silicon carbide and gallium nitride semiconductor suppliers from across the world, multiple power semiconductor experts from academia, as well as direct contact with automotive tier-1 module suppliers and automotive drive train and photovoltaic inverter manufacturers,” says president & CEO Gayn Erickson. “Based on input from this wide range of manufacturers, module suppliers and purchasers of these devices, we are extending our FOX-P wafer-level test and burn-in platform to provide additional new engineering and production solutions featuring these options with up to 18 wafers to be tested in parallel at the same time. By testing and burning in the devices in wafer form, this significantly lowers the cost of test as well as allows these companies to weed out early life failures that otherwise would show up in packaged or even more costly in multi-chip module form,” he adds.
“In addition to the obvious cost advantage of removing these device failures before they are put into a module with many other devices, companies also want to stabilize the inherent early life drift of the threshold voltages (Vth) observed in silicon carbide MOSFETs and then select devices with matching threshold voltages to be put in multi-chip modules,” Erickson continues. “Feedback from current and a number of new potential customers has been very positive, and we have already taken orders for both systems and WaferPaks for these new options. This includes a new major silicon carbide customer announced last month, and another brand-new customer who just this week ordered WaferPaks for a planned FOX-P system purchase from us for their silicon carbide products. We expect these new enhancements to drive incremental bookings and revenue for our FOX-NP systems for new product introduction and engineering qualification needs as well as our FOX-XP multi-wafer systems to be used for high-volume production with these new features.”
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Semiconductor test instrument Power electronics