BS IEC 62047-32:2019 pdf free.Semiconductor devices —Micro-electromechanical devices Part 32: Test method for the nonlinear vibration of MEMS resonators.
For out-of-plane vibrating resonators, the surface of the installing base should be parallelto the horizontal plane.For in-plane vibrating resonators, the surface of the installing baseshould be set to a certain angle about the horizon level, to ensure enough intensity of thereflected laser into the detector.
The vacuum pump and the vacuum chamber should be connected with flexible bellows incase of the vibration propagation from the pump to the chamber.
The angle valve should be tightly shut off to well maintain the vacuum level, and then thepump turned off before operating the test procedure.
Set the frequency of the vibration excitation according to the estimated value of thenatural frequency of the resonator. And then implement the initial frequency scan aroundthe natural frequency within a wide range. The amplitude frequency response and thephase frequency response can be measured according to the vibration displacement ofthe resonators.And record the resonant frequency of the resonator.
Reset the vibration excitation parameters to implement the frequency scan for the secondtime: reducing the interval of the frequency scan to half of that set in the initial frequencyscan and reducing the range of the frequency scan to ten times of the half-powerbandwidth of the amplitude frequency response. The amplitude frequency response andthe phase frequency response can be measured according to the vibration displacementof the resonators.And record the resonant frequency of the resonator.
Compare the resonant frequencies obtained by the initial and the second tests. lf thediscrepancy in the resonant frequencies is smaller than 1 ppm 1 of the resonant frequencymeasured in the second test,either the initial or the second test result can be deemed asthe accurate amplitude frequency response and the phase frequency response. lf thediscrepancy in the resonant frequencies exceeds 1 ppm of the resonant frequencymeasured in the second test, the third time frequency scan with further small frequencyinterval should be implemented,until the discrepancy in last tested resonant frequencyand the previous one is smaller than that 1 ppm of the resonant frequency measured inthe last test.Obtain the bending factor of the amplitude frequency response of the MEMS resonator bythe method set out in Clause 6.
The nonlinear jump phenomenon is presented in Annex B. Figure B.1. The amplitudethreshold for the nonlinear jump can be calculated by substituting the bending factor binto Formula (2).BS IEC 62047-32 pdf download.