2 June 2023
New silicon carbide customer and initial order for Aehr’s FOX-XP multi-wafer test and burn-in
Semiconductor production test and reliability qualification equipment supplier Aehr Test Systems of Fremont, CA, USA has announced a new silicon carbide customer and initial order for a FOX-XP multi-wafer test and burn-in system, multiple WaferPak Contactors, a WaferPak Aligner, and a high-volume production support kit for volume production of silicon carbide MOSFETs for electric vehicles, trucks and train traction inverter modules. The turnkey system including the FOX-XP, WaferPak Contactors and WaferPak Aligner is expected to ship within the next two quarters.
In addition, Aehr has also signed a long-term supply agreement with this new customer covering FOX-XP systems, WaferPaks, WaferPak Aligners, and support. This new customer is a multinational industrial conglomerate and manufacturer of semiconductors, including power semiconductors.
“After conducting an evaluation of technical and commercial requirements, this new customer has decided to move very quickly to purchasing our production FOX-XP solution to accelerate their time to market,” notes president & CEO Gayn Erickson. “This evaluation included cost of ownership, customer device module yield improvement, system capacity and throughput, and device test, burn-in and stabilization coverage. They see the enormous opportunity in the silicon carbide market, particularly for the traction inverters used in electric vehicles including trucks, and in electric commuter trains where they believe they can provide a superior product of long-term reliability and useful life. Importantly, these new applications represent new market drivers for our system. This customer is forecasting to grow their silicon carbide business significantly, which we believe will drive incremental capacity for our FOX systems as well as WaferPak Contactor purchases for capacity and new designs,” he adds.
“Our momentum with this newest customer reflects the acceleration in customer benchmarks and evaluations we are seeing, including shifting from on-wafer evaluations and moving straight to placing orders for our systems and WaferPaks,” Erickson continues.
“Several companies are describing an even stronger and broader shift to multi-die modules for the electric vehicle market, particularly for the main traction inverters used on each electric engine or drive unit. The reduction in size and cost of implementing traction inverters using multi-die modules becomes more critical in achieving cost reductions in electric vehicles that are smaller and that have multiple drive units per vehicle. Unlike traditional internal combustion vehicles with only one engine per vehicle, it is becoming more and more typical to see electric vehicles that come standard or have the option of more than one motor or drive unit in them,” he adds.
“Wafer-level burn-in is critically important to remove infant mortality or early failures of devices before they are put into modules, where the failure of any device would cause the entire module to fail and be scrapped. A single module for use in large traction inverters such as commuter trains might include up to 10, 12 or even 32 devices. Our FOX-XP wafer-level system can test and burn-in up to 18 wafers at a time and enables contact to 100% of the die in a single touchdown up to several thousand die per wafer, with 100% confidence of test burn-in of each device. This is key to companies wanting to put these devices in electric vehicle applications, where up to 1% or more of the die would fail in the field if not burned in,” Erickson says.
“In addition, beyond screening out weak devices or early failures before they are put into a module, there is a need to stabilize the inherent early life drift of threshold voltages of devices that is critical to the module reliability. Silicon carbide devices have voltage thresholds, which is effectively the voltage at which each individual device turns on and will drift during the first use, or during burn-in stress conditions under thermal loads. This can cause individual die in a multi-die module to turn on prematurely relative to the other die in parallel, which can create a disproportional stress on the die, leading to its early failure. This in turn will lead to the failure of the entire module. This failure must be screened out to prevent a ‘walk-home event’ whereupon, with the failure of the traction inverter module, the drive unit will fail, leading to the driver and all the passengers having to get out of the electric vehicle and walk home.”
The FOX-XP system, available with multiple WaferPak Contactors (full-wafer test) or multiple DiePak Carriers (singulated die/module test) configurations, is capable of functional test and burn-in/cycling of integrated devices such as silicon carbide power devices, silicon photonics as well as other optical devices, 2D and 3D sensors, flash memories, gallium nitride (GaN), magnetic sensors, microcontrollers, and other leading-edge ICs in either wafer form factor, before they are assembled into single- or multi-die stacked packages, or in singulated die or module form factor.