I have LIS344ALH accelerometer. I want to polish the top of it to expose the capacitive sensor so that I could sense radiation pressure. Is there any way to expose the sensor without damaging the IC?

[PKuma.16]

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[Eleon BORLINI]

Hi @PKuma.16​ ,

well, this is an interesting application... do you want to use the orthogonal structure (X-Y) of the accelerometer interdigital capacitors to try to detect the components of the Poynting vector?

You could first remove the LGA package (an interesting application note from NXP is here).

Then, you could use a dry-attach method (e.g. Wafer lapping or FIB, focused ion beam, if you can exploit these technologies) to try to be more selective when polishing the top part of the MEMS silicon. The LIS344ALH dies (ASIC and MEMS) are side by side, so you can focus on the MEMS part only.

Please note however that when you expose the capacitive structure to the air, the possibility of a particle or environmental contamination is very high, and particles could affect the device performances, so you should work in a controlled clean environment.

Let me please know if you can go further on this application.

-Eleon