Wafer level burn-in

Is it the industry´s intent to apply wafer-level burn-in (WLBI) to MPUs and ASICs? Package-level burn-in (PLBI) today is facing escalating burn-in power dissipation for these MPU and ASIC devices. The burn-in board (BIB) density (devices/BIB) varies inversely with device power dissipation. However, wafer-level burn-in would indicate the opposite-more devices in a 200 mm diameter. Is it the industry´s intent to apply wafer-level burn-in to memory and more specifically, to DRAM? Here, the power situation is much less problematic than MPUs and ASICs. Yet, unlike logic DRAMs are overwhelmingly wirebonded die which require a test interface (probe) that can penetrate the bond pad´s aluminum oxide without damaging the wafer. There are multi-device under test (DUT) probe technologies available today for ×32 DUT testing; they can cover an area of four square inches. And it may be possible to leverage these technologies to provide full wafer contact-but not for free. How would these compare to the PLBI economic model that we know and love? In the 1993-94 timeframe, several technology issues concerning WLBI were considered risky and required years to solve. So where is the design point today? Is WLBI a static burn-in methodology where applying elevated voltage and temperature is sufficient? Is it dynamic burn-in? Monitored burn-in? In situ burn-in? Or, will it naturally progress to wafer-level test and burn-in (WLTB)? This paper provides an overview of wafer-level burn-in, past and present, and offers a prediction for the future