X-rays help make the MEMs

X-rays produced by the Lawrence Berkeley National Laboratory will play a key role in allowing MEMS structures for optical networks to be fabricated.

X-rays produced by the Advanced Light Source (ALS) at the US Department of Energy’s Lawrence Berkeley National Laboratory will play a key role in enabling Billerica, MA-based Axsun Technologies to fabricate advanced micro-electromechanical structures (MEMS) used in the design of its integrated photonic products.

The ALS has proven suitable for enabling a process called LIGA, a technology developed in Germany that uses X-ray lithography instead of conventional metal machining to create tiny metal structures with sub-micron precision.

In operation, the ALS X-rays are exposed to an acrylic sheet, which is bonded to a silicon wafer containing a mask of the LIGA structures. After the X-rays hit the mask, the acrylic is etched in a manner that creates precise moulds of micro-alignment structures.

Dale Boehme, Director of LIGA Technology for Axsun, said, ‘The ALS is a great synchrotron source for performing LIGA X-ray exposures because it provides maximum power radiated at energies ideal for exposing these moulds.’

The exposed acrylic wafers will be sent to Axsun’s Livermore foundry, where they will be chemically processed, electroplated, lapped and polished, and released from the substrate. This wafer scale process creates thousands of alignment structures on a single 3-inch wafer. The structures are then assembled into the photonic devices.

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