1. 1 Physical Measurement Laboratory Semiconductor and Dimensional Metrology Division Nanoscale Metrology Group MEMS Measurement Science and Standards Project MEMS 5-in-1 RM Slide Set #1 Reference Materials 8096 and 8097 The MEMS 5-in-1 Test Chips – Overview of the MEMS 5-in-1 RMs Photo taken by Curt Suplee, NIST

2. 2 List of MEMS 5-in-1 RM Slide Sets Slide Set #Title of Slide Set 1OVERVIEW OF THE MEMS 5-IN-1 RMs 2PRELIMINARY DETAILS THE MEASUREMENTS: 3 Young’s modulus measurements 4 Residual strain measurements 5 Strain gradient measurements 6 Step height measurements 7 In-plane length measurements 8 Residual stress and stress gradient calculations 9 Thickness measurements (for RM 8096) 10 Thickness measurements (for RM 8097) 11REMAINING DETAILS

3. 3 Outline for the Overview of the MEMS 5-in-1 RMs 1Background 2The MEMS 5-in-1 RM a. What is it? b. The 5 Standard Test Methods c. Uses of the MEMS 5-in-1 RM 3Some Specifics a. The 2 Types of Chips b. The Packaging c. The Chip Designs d. 8 Properties Reported e. Example NIST Reference Values 4Material Available 5Instrumentation 6Summary 7References

4. 4 Why is MEMS Important? A $10.2B industry (in 2011) –Yole forecasts $21.1B industry (in 2017) – doubled from 2011 –Growth rate (13 %/year) is healthy MEMS being pulled into the market (esp. via the consumer market) Spread out over many (say 100) smaller companies –MEMS acquisitions have soared in 2011 (>300 % increase) MEMS is an enabling technology –Improved medical device performance In-vitro diagnostics Micro dispensers for drug delivery Accelerometers in pacemakers Wireless implants –Puts the “Smart” in Smart Phones Accelerometers, gyros, pressure sensors, microphones,… The future will see combination sensors –Etc. As the field continues to grow, NIST can facilitate the introduction of product data sheets to allow inter-comparisons of consumer products. “MEMS Technology has the potential to change our daily lives as much as the computer has.” (Are we there yet?)

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6. MEMS = microelectromechanical systems 5-in-1 = test structures for five standard test methods on one physical test chip 1. Young’s modulus (SEMI MS4) 2. Residual strain (ASTM E 2245) 3. Strain gradient (ASTM E 2246) 4. Step height (SEMI MS2) 5. In-plane length (ASTM E 2244) RM = Reference Material: a material or substance one or more of whose property values are sufficiently homogeneous, stable, and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials. 6 The MEMS 5-in-1 RM (What is it ?)

7. 7 The 5 Standard Test Methods Calculations performed on the MEMS Calculator website (Standard Reference Database 166) These standards include precision and bias data (so considered validated standards) ASTM E 2245 residual strain ASTM E 2244 in-plane length ASTM E 2246 strain gradient 1 2 3 L SEMI MS2 step height SEMI MS4 Young’s modulus 4 5

8. Intended for MEMS designers Test equipment manufacturers –Who may want to buy in bulk to sell with their instruments IC and MEMS foundries and services Uses of the MEMS 5-in-1 To validate use of the documentary standards (so companies can compare their in-house measurements taken on the RM with NIST measurements) To characterize or validate a process To take local measurements To compare measurements meaningfully (e.g., between suppliers and customers) To trouble-shoot a process (to improve yield and track failure sources to speed development) To calibrate an instrument 8 Photo taken by Curt Suplee, NIST

9. 9 The 2 Types of Chips RM 8097 –Fabricated using a polysilicon multi-user surface- micromachining MEMS process with a backside etch –Material properties of the first or second polysilicon layer are reported –Chip dimensions: 1 cm x 1 cm RM 8096 –Fabricated on a multi-user 1.5 µ m CMOS process followed by a bulk-micromachining etch –Material properties of the composite oxide layer are reported –Chip dimensions: 4600 µ m x 4700 µ m

10. 10 NIST-on-a-Chip-type-of Packaging  testing solution provided  all measurements can be performed in this package lid chip PZT Photo taken by Erik Secula, NIST

11. 11 The Chip Designs Each RM has 6 sections 1.Young’s modulus (uses SEMI standard MS4) 2.Residual strain (uses ASTM standard E 2245) 3.Strain gradient (uses ASTM standard E 2246) 4.Step height (uses SEMI standard MS2) 5.In-plane length (uses ASTM standard E 2244) 6.Certification Plus RM 8097 RM 8096

12. 12 8 Properties Reported [using 5 Test Methods (TMs)] 1. Young’s modulus (uses SEMI standard MS4) 2. Residual strain (uses ASTM standard E 2245) 3. Strain gradient (uses ASTM standard E 2246) 4. Step height (uses SEMI standard MS2) 5. In-plane length (uses ASTM standard E 2244) 6. Residual stress (calculations in Young’s modulus TM SEMI MS4) 7. Stress gradient (calculations in Young’s modulus TM SEMI MS4) 8. Beam thickness a. For RM 8096 [uses step height TM (SEMI MS2) with electro-physical technique] b. For RM 8097 [uses step height TM (SEMI MS2) with opto-mechanical technique] 12

13. Measurement NIST Reference Value ± Expanded Uncertainty (for k=2 for ≈ 95 % confidence) 1. Effective Young’s modulus, E 56.6 GPa ± 17.8 GPa 2. Effective residual strain,  r –2.83×10 –3 ± 0.71×10 –3 3. Effective strain gradient, s g 1101 m –1 ± 167 m –1 4. Step height, step1 AB 0.499 µm ± 0.108 µm 5. In-plane length, L (at 25×) 202.2 µm ± 3.0 µm 6. Effective residual stress,  r –160 MPa ± 67 MPa 7. Effective stress gradient,  g 62.3 TPa/m ± 18.9 TPa/m 8. Thickness, t oxide 2.65 µm ± 0.20 µm Example NIST Reference Values for RM 8096 N OTE : Effective values are reported if there are non-idealities associated with the geometry and/or composition of the test structures. 13

14. 14 Material Available NIST SP 260-177: A User’s Guide (2013 Edition) The 5 standard test methods Data analysis sheets –On the MEMS Calculator website (Standard Reference Database 166) –Accessible via the NIST Data Gateway (http://srdata.nist.gov/gateway/) with the keyword “MEMS Calculator”http://srdata.nist.gov/gateway/ –Performs the calculations and verifies the data Report of Investigation (ROI) –Includes NIST Reference Values: A best estimate of the true value provided on a NIST Certificate/Certificate of Analysis/Report of Investigation where all known or suspected sources of bias have not been fully investigated by NIST

15. Instrumentation 1.Optical interferometric microscope (or comparable instrument) –In-plane length –Residual strain –Strain gradient –Step height –Thickness RM 8096: When applicable platforms are reflective RM 8097: For measurement of B and/or C (and perhaps A) 2.Optical vibrometer (or comparable instrument) –Young’s modulus 3.Stylus profilometer (or comparable instrument) –Thickness RM 8096: When applicable platforms are not reflective RM 8097: For measurement of A (for a lower uncertainty value), if used C 15

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17. 17 References Overview articles 1. J. Cassard, J. Geist, and J. Kramar, “Reference Materials 8096 and 8096 – The Microelectromechanical Systems 5-in-1 Reference Materials: Homogeneous and Stable,” More-Than-Moore Issue of ECS Transactions, Vol. 61, May 2014. 2. J. Cassard, J. Geist, C. McGray, R. A. Allen, M. Afridi, B. Nablo, M. Gaitan, and D. G. Seiler, “The MEMS 5-in-1 Test Chips (Reference Materials 8096 and 8097),” Frontiers of Characterization and Metrology for Nanoelectronics: 2013, NIST, Gaithersburg, MD, March 25-28, 2013, pp. 179-182. 3. J. Cassard, J. Geist, M. Gaitan, and D. G. Seiler, “The MEMS 5-in-1 Reference Materials (RM 8096 and 8097),” Proceedings of the 2012 International Conference on Microelectronic Test Structures, ICMTS 2012, San Diego, CA, pp. 211-216, March 21, 2012. User’s guide 4. J.M. Cassard, J. Geist, T.V. Vorburger, D.T. Read, M. Gaitan, and D.G. Seiler, “Standards Reference Materials: User’s Guide for RM 8096 and 8097: The MEMS 5-in-1, 2013 Edition,” NIST SP 260-177, February 2013 (http://dx.doi.org/10.6028/NIST.SP.260- 177).http://dx.doi.org/10.6028/NIST.SP.260- 177 Standards 5. SEMI MS4-0212, “Test Method for Young’s Modulus Measurements of Thin, Reflecting Films Based on the Frequency of Beams in Resonance,” February 2012. (Visit http://www.semi.org for ordering information.)http://www.semi.org 6. SEMI MS2-0212, “Test Method for Step Height Measurements of Thin Films,” February 2012. (Visit http://www.semi.org for ordering information.)http://www.semi.org 7. ASTM E 2245-11, “Standard Test Method for Residual Strain Measurements of Thin, Reflecting Films Using an Optical Interferometer,” December 2011. (Visit http://www.astm.org for ordering information.)http://www.astm.org 8. ASTM E 2246-11, “Standard Test Method for Strain Gradient Measurements of Thin, Reflecting Films Using an Optical Interferometer,” January 2012. (Visit http://www.astm.org for ordering information.)http://www.astm.org 9. ASTM E 2244-11, “Standard Test Method for In-Plane Length Measurements of Thin, Reflecting Films Using an Optical Interferometer,” December 2011. (Visit http://www.astm.org for ordering information.)http://www.astm.org Thickness articles 10. J.C. Marshall and P.T. Vernier, “Electro-physical technique for post-fabrication measurements of CMOS process layer thicknesses,” NIST J. Res., Vol. 112, No. 5, pp. 223-256, 2007. 11. J.C. Marshall, “New Optomechanical Technique for Measuring Layer Thickness in MEMS Processes,” J. of Microelectromechanical Systems, Vol. 10, No. 1, pp. 153-157, March 2001. Fabrication 12. The RM 8096 chips were fabricated through MOSIS on the 1.5 µ m On Semiconductor (formerly AMIS) CMOS process. The URL for the MOSIS website is http://www.mosis.com. The bulk-micromachining was performed at NIST.http://www.mosis.com 13. The RM 8097 chips were fabricated at MEMSCAP using MUMPs-Plus! (PolyMUMPs with a backside etch). The URL for the MEMSCAP website is http://www.memscap.com.http://www.memscap.com

18. SEMI’s MEMS/NEMS Committee –MEMS Materials Characterization TF ASTM’s E08 Committee on Fatigue and Fracture –E08.05 Subcommittee on Cyclic Deformation and Fatigue Crack Formation E08.05.03 Task Group on Structural Films for MEMS For industry cost-share and engineering support –MOSIS (for RM 8096) –MEMSCAP (for RM 8097) NIST –Statistical Engineering Division, Measurement Services Division, Center for Nanoscale Science and Technology, Public and Business Affairs Office –Quality –Experts –MEMS Measurement Science and Standards Project Test Structures Subgroup 18 Acknowledgment Mark Crockett (MEMSMART) Win Baylies (BayTech Group) Jon Geist (leader), Richard Allen P. Thomas Vernier Busbee Hardy Sreeramesh Kalluri (Ohio Aerospace Institute) Stefan Leigh Robert Watters Ted Doiron Theodore Vorburger and David Read Craig McGray (Modern Microsystems) Yaqub Afridi (Potomac Networks) Brian Nablo