ASN #6 - In & Around Our Industry - MEMS

Micragem™ – An SOI-based MEMS Process Platform

Posted by (Micralyne) on December 6, 2006
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Micralyne’s robust, standardized fabrication process reduces time-to-market.

One key issue companies face is time-to-market — how long it takes to move a MEMS-based product from an idea to generating revenues. Micragem™ is an SOI-based MEMS fabrication process with a set of design and process guidelines used to prototype and manufacture different types of MEMS components in a standardized fashion. Developing a product based on Micragem™ reduces time-to-market by taking advantage of Micralyne’s existing characterized processes.

SOI technology was originally developed to avoid charge leakage in p-n junctions, but due to the robustness of the single crystal device layer as a structural material for silicon microstructures, SOI substrates are also attractive to MEMS applications. Micralyne developed Micragem™ as a prototyping process on SOI that is simple, versatile, and mature.

The steps

At the basic level, Micragem™ is a four-mask lithography and wafer-bonding process:

• Mask 1: Thick glass wafer is patterned for the first etch.

• Mask 2: Metal is patterned on the glass substrate, both on the non-etched surface and in the etched features.

• Mask 3: Device layer of an SOI wafer is bonded to the glass wafer. The handle and BOX layers of the SOI are then removed. Micralyne’s proprietary low stress gold is deposited on the silicon surface, and lithographically patterned to produce wires, bond pads, and reflective surfaces.

• Mask 4: The final process in the DRIE (Deep Reactive Ion Etch) to vertically etch the silicon patterns and release mechanical elements.

The result is a reliable, robust, and manufacturable MEMS device.

 

A MEMS optical switch mirror developed using the Micragem fabrication process. (Courtesy: Micralyne)

Faster, better, cheaper

The potential of this simple process platform in the MEMS field is substantial. The process is well suited to prototype miniaturized micro-mirrors, diaphragms, micro-channels, cantilever beams, valves, comb drives and much more. In turn, these devices can be used as the basis to produce products such as mirror-based optical switches that increase the speed of fiber optic networks, inertial devices for automotive safety applications, and pressure sensors that can accurately perform while withstanding extreme harsh environments.

Users of Micragem™ benefit by reducing MEMS development costs, creating higher levels of reliability and performance earlier in development, and efficiently prototyping and testing their new product ideas.