Mechanics and Tribology of MEMS Materials - prod.sandia.gov ...

More documents

Recommendations

Info

Fracture Strength (GPa) 6 5 4 3 2 1 Poly 21, Reticule Set 184 Sandia Other Round-Robin Participants: Toyota, Johns Hopkins, Cal Tech 0 0.2 0.4 0.6 0.8 1 Probability Fig. 1.2. Comparison of strength data obtained at Sandia (using a truncated-cone probe), compared to strength data obtained by other round-robin participants. Based on [8]. One of the primary distinctions between the Sandia method and all other methods was the use of a truncated cylinder to engage the ring-end of the pull-tab specimen. This tip geometry required that a significant downward force, ~400 mN, be applied to the substrate to prevent the conical tip from sliding over the engagement ring rather than pulling the ring to failure. This downward force was over an order of magnitude higher than the observed lateral forces associated with silicon failure. While corrections were made to adjust for the contributions of sliding friction and the resultant force vector resolved in the direction of the gage length, this conical engagement geometry remained suspect. To alleviate the potential problems associated with a conical engagement tip, a cyclindrical sapphire tip was fabricated, as shown in Fig 1.3. The straight, vertical sidewalls of the cylindrical tip required much less downward force (essentially zero) to prevent slip over the specimen ring. The resulting strength values obtained with the cylindrical tip were substantially lower than those obtained with the truncated cone. As shown in Fig. 1.4, the strength values and scatter measured using the cylindrical tip with a 10 mN downward force, are quite comparable to those obtained by other round-robin participants. With a downward force of 3 mN, the observed strength values were slightly below the round-robin observations. Therefore, the use of a low downward force cylindrical tip appeared to alleviate much of the discrepancy in test method. 16
Fig. 1.3. SEM image of cylindrical sapphire tip geometry for engaging pull-tab tensile specimens. The diameter of the cylinder end is 35 µm. Fracture Strength (GPa) 6 5 4 3 2 1 0 0.2 0.4 0.6 0.8 1 Probability Fig. 1.4. Strength distributions obtained using the cylindrical tip at two levels of downward force (normal load, 10 mN and 3 mN), compared to the results from the round-robin experiments (Sandia: black circles, Others: gray “x”) 17 ~400 mN normal load conical tip 98 tests 10 mN normal load cylindrical tip 14 tests 3 mN normal load cylindrical tip 12 tests RS184 data from other research groups
Page 1 and 2: SANDIA REPORT SAND2004-1319 Unlimit
Page 3 and 4: SAND2004-1319 Unlimited Release Pri
Page 5 and 6: Contents ACKNOWLEDGEMENTS..........
Page 7 and 8: 6.5 Summary........................
Page 9 and 10: List of Figures Figure 1.1 SEM micr
Page 11 and 12: Figure 6.2 Contact between an elast
Page 13 and 14: Preface Our team was involved in a
Page 15: strength. The subsequent chapter di
Page 19 and 20: Fig. 1.5. Schematic of primary feat
Page 21 and 22: Fig 1.7 Double-hinged pull-tab tens
Page 23 and 24: Fig 1.10. SEM image of optical forc
Page 25 and 26: 2 Strength Distributions in SUMMiT
Page 27 and 28: 2.2 Critical Flaw Size Evaluation T
Page 29 and 30: Fig. 2.5. SEM micrograph of pull-ta
Page 31 and 32: (1) Differences in surface roughnes
Page 33 and 34: 3 The Role Of Microstructure In SUM
Page 35 and 36: crystallographic orientation of a g
Page 37 and 38: direction. Also, maximum stress loc
Page 39 and 40: 3.4 References 3.1 Randle, V., Micr
Page 41 and 42: has the advantage of distributing t
Page 43 and 44: and servovalve at a strain rate of
Page 45 and 46: 4.6 References 4.1. TJ Garino, AM M
Page 47 and 48: microscopy studies. As a first step
Page 49 and 50: Fig. 5.2. Orientation imaging of a
Page 51 and 52: Fig. 5.5. Orientation imaging of a
Page 53 and 54: 6 Novel Techniques for Measurement
Page 55 and 56: of adhesion, and, (iv) a smaller co
Page 57 and 58: Force (mN) Fig. 6.5. Typical load-d
Page 59 and 60: 7 Impact of Silane Degradation Due
Page 61 and 62: All samples were coated with alkyls
Page 63 and 64: the friction structure and the cali
Page 65 and 66: 7.4 RESULTS 7.4.1 Simulation of dos
Page 67 and 68:
Dose (MeV/g) Fig. 7.4. Results of X
Page 69 and 70:
heating on contact angle for PFTS.
Page 71 and 72:
the C-C backbone of the PFTS molecu
Page 73 and 74:
The increase in static friction for
Page 75 and 76:
8 Friction and Wear of Selective Tu
Page 77 and 78:
During processing of microelectrome
Page 79 and 80:
actuator. After unloading, the devi
Page 81 and 82:
9 Conclusions and Recommendations T
Page 83:
10 Distribution 3 MS 0889 M.T. Dugg
show all

Mechanics and Tribology of MEMS Materials - prod.sandia.gov ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?