X-Fab Enhances Optical Sensor Process with BSI Integration

X-FAB Silicon Foundries, the analogue/mixed-signal and specialty foundry, has recently announced the addition of a back-side illumination (BSI) capability to its XS018 180nm CMOS semiconductor process, specifically designed for optical sensors.

By incorporating BSI technology, the performance characteristics of imaging devices can be significantly enhanced. This innovation ensures that the incident light can reach the pixels without obstruction from the back-end process metal layers, resulting in an increase in fill factors by up to 100%.

This advancement is particularly advantageous in scenarios with low-level illumination, as it enables higher pixel light sensitivity. Additionally, BSI helps to reduce crosstalk between neighboring pixels by shortening light paths, ultimately leading to improved image quality.

While small-pixel BSI solutions for 300mm wafers are common in high-volume consumer applications, options for image sensors with stitched large-pixel arrangements on 200mm wafers have been limited, especially when customization is required.

"BSI technology has gained significant traction in modern imaging devices due to its ability to enhance image quality by positioning light-sensitive elements closer to the light source and eliminating unwanted circuitry obstructions," explains Heming Wei from X-FAB. "While consumer electronics have been the primary adopters, opportunities are now emerging in industrial, automotive, and medical sectors. X-FAB's BSI foundry solution opens up new possibilities by offering heightened sensitivity, larger image sensor dimensions, and increased pixel capacities."

The introduction of the new X-FAB BSI capability opens doors for customers with diverse application needs, including those in X-Ray diagnostic equipment, industrial automation systems, astronomical research, robotic navigation, and vehicle front cameras.

Utilizing the XS018 platform, known for its high readout speeds and low dark currents, X-FAB will manufacture image sensors with multiple epi options. Customers can opt for an ARC layer that can be fine-tuned to meet specific requirements.

Furthermore, X-FAB provides a comprehensive support package that guides customers from initial design to the shipment of engineering samples, complete with a detailed Process Design Kit (PDK).