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In-line Inspection of Wafer Backside after Thinning and Metallization for Power Semiconductors

Wafer Thinning

Wafer thinning has been used for many years in the microelectronic industry for a wide range of applications. In the last years, wafer thinning process has become more critical than ever due to the demand of ultra-thin and high-performance components, and consequently requiring better process control solutions. This is even more critical for power semiconductor devices such as MOSFET or IGBT where the backside of the die play an active role.

Power Semiconductors

Back grinding is the most popular process method used to reduce the wafer thickness as it is a low cost and high speed technic. However, the mechanical stress and heat applied during this process can generate some damages. These damages need to be carefully understood and control as they impact the fab manufacturing yield as well as the performance and reliability of the final device.

UnitySC’solutions: 4See Series

UnitySC developed new inspection technics compliant with high volume manufacturing allowing to perform the full wafer characterization after back grinding and after wafer metallization. The 4See Series can be configured with a Deflector module and Edge module to adress the wafer thinning applications.

  • Deflector module: A unique and powerful approach to perform high throughput full wafer surface macro inspection based on Phase Shift Deflectometry. Deflector module allows detecting topographic defects with only few nanometer height range on wafer frontside and backside surfaces. Combined with wafer reflectivity and global topography results, Deflector module provides a reliable method to detect defects such as sliplines, comets, grinding marks, star cracks, and more.
  • Edge module: A module used to perform the wafer edge inspection (Top, Top Bevel, Apex, Bottom Bevel, Bottom), allowing a combination of high lateral resolution with a large depth of focus. The Edge module relies on confocal chromatic technics and can detect typical defects such as chips, shells, cracks, contamination areas and more that can propagate on the wafer.

UnitySC delivers visionary technologies that foster progress for people. We are recognized as a key player in inspection and metrology combining advanced technologies to enable higher yields and faster time to market.

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+33 (0)456 526 800