DESIGN OF A TESTING MACHINE FOR MICRO-DEVICES Follow up to Clément Gabry’s master thesis on Structural Resistance of Silicon Membranes 1 12/10/2014CERN PH-DT-EO

Measurement devices displacement measurement load measurement optical table 12/10/2014CERN PH-DT-EO 2

12/10/2014CERN PH-DT-EO 3

CSEM Machine PI linear stage 17 mm travel ~ 1 um accuracy Load cell 2N range, 0.1mN accuracy 20N range, 1mN accuracy 12/10/2014CERN PH-DT-EO 4

New Machine Linear measurement travel range : > 1 mm resolution/incremental motion: 0.1 um Load cell ~ 1-25 N range 0.5 mN accuracy 12/10/2014CERN PH-DT-EO 5

Displacement type of test : apply displacement, measure load. type of devices linear actuator linear stage 12/10/2014CERN PH-DT-EO 6

Linear actuator 12/10/2014CERN PH-DT-EO 7 Advantages Simple geometry Allows an on-axis motion at all times Have good enough specifics Easy to mount Easy to replace Reasonable prices Price ~ 3’000 CHF

Linear Actuator Drawbacks More compliance in fixing method Compliance in mounting device Alignment problem (angular) Smaller travel ranges 50 N might introduce bending forces None linear encoder : backlash 12/10/2014CERN PH-DT-EO 8

Linear Actuator Solutions Hole “Meplas” BUT Feasible? Loses precision? 12/10/2014CERN PH-DT-EO 9

Linear Actuator Solutions external device Feasible Compliance Small alignment error 12/10/2014CERN PH-DT-EO 10

Piezo actuators very good precision good temperature ranges easy to mount and use price ranges affordable BUT travel range NOT enough (10s of microns) 12/10/2014CERN PH-DT-EO 11 Price ~ 2-4’000 CHF

Micro positioning stages some avoid the alignment problem very easy to mount stiffness BUT load just not enough 12/10/2014CERN PH-DT-EO 12 Price ~ 15’000 CHF

Piezo scanning stages Very good precision Possible to mount them on axis BUT Travel range too small (38 um) 12/10/2014CERN PH-DT-EO 13 Price ~ 9’000 CHF

Nano positioning stages Very good precision Easy to mount, or re-use Stiffness and “high loads” Long travel ranges BUT Out-of-axis loading problem 12/10/2014CERN PH-DT-EO 14 Price ~ 10’000 CHF

Nano positioning stage How to deal with the out of axis load? external device compliance adds weight to the load 12/10/2014CERN PH-DT-EO 15

Load Cells Positioning of the load cell on the actuator side non alignment problem again on the support : easy to fix easy to align easily changeable 12/10/2014CERN PH-DT-EO 16

Load Cells Type of load cell “donut type” avoids alignment problems Easy to fix stiffer than others 12/10/2014CERN PH-DT-EO 17

Optical Tables Gives a high flexibility in positioning Not too expensive (so far) Probably better than rails 12/10/2014CERN PH-DT-EO 18

Next step Modeling and analysis of errors influence of the notch-load non alignment influence of the out of axis load influence of the importance of symmetry influence of temperature on (optical) table and devices 12/10/2014CERN PH-DT-EO 19