Mirror array for industrial applications

IMEC has developed a monolithically integrated 11 megapixel micro-mirror array for high-end industrial applications, claimed to be a world first both in terms of pixel density and reliability.

Each mirror in the array is 8 x 8 μm and can be individually tilted by the high-speed integrated CMOS circuitry underneath the array.

The device fits in IMEC’s CMORE initiative, which offers solutions for continued system scaling, not by shrinking CMOS but by focusing on monolithic co-integration of heterogeneous technology.

The 10 cm² mirror array has a pixel density that is almost double that of others currently available. And IMEC has demonstrated that its mirrors show no creep and meet a 10¹² cycles mechanical lifetime.

Integrated arrays such as this are used in, for example, video projection or lithography mask writers.

The mirrors were fabricated on top of foundry high-voltage 0.18 µm CMOS 200 mm wafers with six interconnect levels. The array was built using an SiGe-based MEMS platform, meeting the mirror’s mechanical reliability requirements, device flatness and compatibility with high-speed CMOS.

Poly-SiGe was chosen as structural material for the mirrors, instead of Al. Poly-SiGe solves many of the reliability issues of Al-based mirrors and is compatible with above CMOS processing, allowing a smooth integration with the CMOS chip below.