I worked on the development of MEMS gyro components for Honeywell and Benchmark 15 years ago. They are indeed extremely sensitive components, measuring and controlling pitch, yaw, and thrust on avionics. They are actually a miniature spinning gyroscope on a gantry, and the gantry measured the interial forces of the spinning gyro. We initially had a high fallout of these components but had great difficulty testing them at different stages of the process to determine where the shock/vibration was occurring that caused them to fail. So I assembled a shock/vibration reader to the output of the MEMS and attached it directly to the CCA, which in turn transmitted a Bluetooth signal to a data receiver/recorder. I tracked the shock/vibe on a sample of three parts from Honeywell's factory through the delivery truck through all of the manufacturing processes. It was clear we were looking for a process that delivered steady-state or at least re-curring vibration of such intensity that a sudden drop/upward shock or huge thrust coupled with high inertial forces was causing the failures, as seen by 500x views of the damaged areas. The three samples tracked very similarly throughout their life from fabrication through final assembly/inspection. I could only track one at a time, but all three recorded the greatest shock and either partial/intermittent failure or full failure after the in-line wash process. The cavitation of the wash water sprayers caused all three to fail, and were the greatest shock/vibration readings in their short little lives. So we changed to a different assembly process, putting the MEMS on after all other processes were completed and used a manual wash process with full blow-off and a short bake for 15 minutes at 105 C. 

No more failures.

Changes were made to the physical design of the MEMS at that time, and for all I know that could be the component you are dealing with today. Or it may be something entirely different. But I do know this; the wash process can be very destructive on MEMS components for the reasons stated above.

Odin



-----Original Message-----

From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory

Sent: Thursday, September 20, 2018 9:18 AM

To: [log in to unmask]

Subject: [TN] 6-axis MEMS Gyroscope/Accelerometer assembly



Good morning everyone,



We're quoting this little 1.5" X 2.5" assembly that has a TDK/InvenSense

6-axis MEMS Gyroscope/Accelerometer on it (PN# ICM-20648). I've not

assembled a board with one of these devices on it before. When I read the

datasheet, and then the handling guidelines for these parts (

http://www.invensense.com/wp-content/uploads/2015/02/InvenSense-MEMS-Handling.pdf

) I was quite surprised how fragile these things are seeing how they are

primarily used on wearable devices where they are going to see a lot of

shock. Yeah I know it is a MEMS part, but it would seem to me if it can

survive all the abuse it will see being in a wearable device that it would

be a little more robust during assembly.



So have any of you who have placed these sort of devices, have to make a

bunch of changes in their standard assembly processes and stockroom

handling practices to accommodate these parts?



Thanks in advance,



Steve

-- 

Steve Gregory

Kimco Design and Manufacturing

Process Engineer

(208) 322-0500 Ext. -3133



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