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Originally posted by BobF
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Very interesting. If you read this you will see the complexity of the MEMS manufacturing process and see exactly what Yuval Cohen meant when he said that the laws of physics were somewhat different at the scale of MEMS structures than people are normally familiar with in the behaviour of normal sized objects and materials!first run of Phase IV wafers revealed that the devices did not meet a critical mechanical specification, which in turn increased the voltages required to operate the devices. As was also reported all our attempts to try work with and around the higher voltages ultimately left us no alternative but to return to the fab with instructions to re-spin / reproduce the wafer s.being compelled to work with much high voltages than originally intended led us rather significant discovery concerning the “points of contact” of our device. This discovery warranted our applying for a patent due to the significant benefits it provides in improving the yield and reliability of the product. Working closely with our fabrication partner we were able to implement this discovery into the current fabrication process, with wafers containing this innovation expected to be delivered over the coming weeks. ..."
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One of the problems that would have been involved is that, at the very small scale, a positive charge needed to cause the moving part to be attracted to and locked to the fixed part at one extremity of travel. The opposite needed to occur with a negative charge. But in both cases, when the charge is reversed, the moving part needs to released immediately. If it sticks to any degree, it's back to the drawing board. It is quite possible that this was one of the issues that necessitated the new wafer run. Maybe the cryptic "dissipation layer" remarks in one of the announcements give a clue to this.
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