November 3, 2011 — Ziptronix Inc., semiconductor bonding technology developer, shared the results of recent collaborations with major image-sensor manufacturers: Ziptronix ZiBond direct bonding process contributed minimum distortion in backside illuminated (BSI) image sensors.
The Ziptronix direct bonding technology delivered the lowest distortion of any process for manufacturing BSI image sensors, said Ziptronix CEO Dan Donabedian. "Minimal distortion means pixels can be scaled smaller, and that means increased image sensor resolution, more die per wafer, improved image sensor yields and lower production costs."
BSI image sensor manufacturing typically requires bonding a silicon CMOS wafer to a non-CMOS handle wafer. Because this bonding technology does not involve a large coefficient of thermal expansion (CTE) mismatch, it does enable very low distortion which is required for scalable color filter array overlay on the exposed photodiodes after thinning of the bonded CMOS wafer.
Wafer distortion introduced during the bonding process can compromise the overlay and limit pixel scaling. ZiBond’s inherent capacity for high bond strength at low temperature effectively minimizes this distortion compared to the competing bond technologies (adhesive and copper thermo-compression), the company reports. This enables submicron pixel scaling; 0.9um pixel BSI image sensors have already been fabricated and work on 0.7um pixel BSI is underway.
BSI image sensors are replacing frontside illuminated image sensors for digital cameras and smartphone cameras, as well as other applications.
Sony Corp. recently licensed the Ziptronix ZiBond technology for BSI image sensor manufacturing.
Ziptronix develops low-temperature direct bond technology for a variety of semiconductor applications, including backside-illuminated (BSI) sensors, RF front-ends, pico projectors, memories and 3D integrated circuits. Visit www.ziptronix.com.