Ziptronix, a developer of low-temperature direct bond technology for semiconductor applications has announced that its ZiBond direct bonding technology delivered minimum distortion for manufacture of backside illuminated (BSI) image sensors. The company stated that collaborations with manufacturers of image sensors confirmed the effectiveness of its bonding technology.
Frontside illuminated image sensors are being used for smartphones and digital camera applications. As BSI image sensors are proving to be more advantageous than frontside illuminated image sensors, the former is being widely adopted. Minimal distortion leads to increased resolution of the image sensor, smaller pixel scaling, better image sensor yields, more die per wafer and lower cost of production.
In BSI image sensors, the photodiodes are not illuminated via the CMOS interconnect stack. For manufacturing these sensors, silicon CMOS wafers are bonded to non-CMOS handle wafers. The bonding technology employed does not cause any significant mismatch in the coefficient of thermal expansion. This leads to low distortion, which is needed for the overlay of the scalable color filter array on photodiodes that become exposed following reduction in the thickness of the bonded CMOS wafer.
ZiBond technology for manufacture of BSI image sensors minimizes distortion due to its high bond strength. During the process of bonding, any distortion of the CMOS wafer can limit pixel scaling and affect the overlay. When compared to other bond technologies, such as copper thermo-compression and adhesives, ZiBond technology minimizes distortion. This allows submicron pixel scaling leading to fabrication of 0.9 µ pixel BSI image sensors.
Sony has licensed Ziptronix’s ZiBond technology for manufacture of BSI image sensors.
Source: http://www.ziptronix.com/