AP designed the MEMS system, and has patented every aspect of...

AP designed the MEMS system, and has patented every aspect of that functional design that they can. But the FAB decides how they will actually run the machines in order to implement those designs. I expect mostly that the actual techniques employed to make a shape or structure will not be known to the customer for whom the device is produced. It is inevitable that a MEMS FAB will want to patent some features of the production techniques used in the devices they make for their customers. That is leverage on their part to ensure that they continue to do business with the client, as well as simply being part of their repertoire of production techniques. Yes there is some mutual reliance on each other. It is called mutual trust between commercial partners. And yes, both parties need each other, but that is where manufacturing and licensing agreements take place. If AP shifts manufacture to other FABs those FABs will undoubtedly have their own undisclosed techniques to make the same product that work best on their equipment. If they get info from the other FAB that may save them time, and I expect they will assume that info is worth something to them, due to the development time involved. They may accept that and pay for it. Or they may already know how to make the structures from other things they have done in the past, and just replicate the development work themselves.

It is clear that during the time that AP has worked with EM there have been a large number of design changes to the basic structures. These are what the GEN-n designations all signify. The development as done with EM will have provided AP with insight into better ways of doing things, and in turn led to far better designs. Who do you think that information belongs to? Do you think that would be any different from earlier MEMS development work done with SONY and Tower? At the end of the day there is no point for any FAB to own info pertaining to the manufacture of a MEMS device, and try to make a copy for themselves if that MEMS requires the sophisticated code that runs in the ASIC to drive the patented DSR tech that AKP owns exclusively. I imagine it would be pretty hard to reverse engineer the algorithms behind the code that are represented by the coded instructions from the ASIC. And without the DSR functionality the chip is not much use except as a source of ultrasonics.

AIMHO, DYOR.