EV Group Presents Stacked Image Sensor Alignment and Bonding System

PR Newswire: EV Group (EVG) announces the latest version of its EVG40NT automated measurement system, which is designed to work with the company's GEMINI FB fusion wafer bonding system to support the manufacture of next-generation 3D-integrated CMOS image sensors. The enhanced EVG40NT measures wafer-to-wafer alignment accuracy to within 40 nm (3 sigma) (the original EVG40NT used to have 100nm accuracy). Its seamless software integration with the GEMINI FB provides a closed-loop fusion bonding control system that enables the manufacture of less than 2um pitch TSVs. These tighter specifications are necessary for enabling the production of 3D-integrated image sensors.

"EV Group's GEMINI FB fusion wafer bonding platform is the de facto industry standard for CMOS image sensor production, and already leads the industry in wafer-to-wafer alignment accuracy due to our proprietary SmartView alignment technology," stated Dr. Thorsten Matthias, business development director at EV Group. "Measuring and mapping each die gives valuable insight into local stress variations created during upstream processes, which can cause distortions and local misalignments further downstream."

Fusion wafer bonding for 3D-integrated image sensors is a room-temperature bonding process, which eliminates misalignment due to thermal expansion mismatch between the wafers. Having the ability to inspect the quality of the wafer bond and measure alignment accuracy prior to the final annealing step provides an easy rework path, thereby enabling 100% yield for wafer stacking. The GEMINI FB platform combines EVG's LowTemp plasma activation technology, wafer cleaning, SmartView wafer-to-wafer alignment and fusion wafer bonding in a single fully automated high-volume-manufacturing system. The EVG40NT performs highly accurate, non-destructive, top-to-bottom side alignment accuracy measurements on double-sided structured wafers or bond interfaces, as well as critical dimension and box-in-box measurements of single and double-sided structured wafers.

"Next-generation image sensors are the technological frontrunners for 3D-IC manufacturing technology," according to Hermann Waltl, executive sales and customer support director at EV Group. "High-density TSV arrays, sub-micron-diameter TSVs and ultra-thin wafers have all been successfully transferred into high-volume image sensor manufacturing. ...that adoption of wafer-to-wafer 3D stacking for image sensors is well underway."

EVG40NT automated measurement system

Thanks to PD for the info!