SINTEF movemems a standard process for piezoelectric microsystems prototyping Frode Tyholdt
Background Small and medium companies/ Universities have ideas for piezomems Difficult to make Need special tools and expertise Companies are looking for high volume solutions Prototyping Deposition Fabrication The market for piezomems is increasing rapidly. Main market drivers are: Ink-jet printers Ultrasonic tools A lot of other interesting devices are emerging piezomems accelerometers
piezomems competence centre The competence centre aims to act as contact point for interested parties and covers the whole production process for piezoelectric microsystems World-class piezoelectric thin films (PZT). e 31,f ~ -14 C/m 2 @ 10 Hz Deposition process and tools for high-performance PZT thin films on silicon wafers Modelling software specifically for piezomems Modelling of device ideas and design assistance Evaluation of alternative processing routes Testing services and sophisticated testing equipment Manufacturing of prototypes Small scale production using 150 mm wafers Go to: www.piezovolume.com
The movemems process movemems: a piezomems fabrication process w/ standard material parameters and procedures piezovolume: FP7 project to upscale movemems to high volumes (200 mm wafers) movemems design handbook movemems fabrication procedure PZT thin film deposition End piezomems product piezomems design tools Chemical solution deposition piezomems device fabrication (wafer level) Packaging and integration with electronics movemems process add-on For Coventorware
FP7 piezovolume (2010 2013) PZT thin film deposition tools and procedures Design handbook Fabrication procedures VERMON Automated chemical solution deposition tool End piezomems product piezomems design tools In-line quality monitoring tools piezomems device fabrication procedures (wafer level) Packaging and integration with electronics Sputtering tool
piezomems modelling tool piezomems modelling tool 3D parametric library of standard piezomems components Integration with FEM software Material parameters included in process design kit (PDK) Process emulation (virtual manufacturing) 2D masks + description of fabrication process to create a voxel based 3D solid model. Virtual manufacturing Save Money by finding problems before fabrication. Enhance communication with highly detailed, interactive 3D models. Reduce time-to-market and gain a competitive advantage. Improve documentation and reduce document creation effort. Enhance Yield through improved design rules and defect modeling. Beam (in green): 400 x 50 um^2, 3um thick E=1.6e5 MPa, ν=0.2 Piezoelectric material (in magenta): 300 x 50 um^2, 1um thick Elastic-AnIso piezomems beam in Coventorware ARCHITECT. Virtual manufacturing of MEMS bond pads and comb drive. Courtesy X-FAB Semiconductor Foundries, AG.
Deposition tools CSD Adaptation of Solar-semi cluster coater tool Throughput goal 4 wafers/h µm (65 nm/min) on 200 mm wafers using new automatic CSD tool (15.000 wafers/y @ 43 % uptime) Performance goal e 31,f ~ -14 C/m 2 Deposition cost 10-20 /wafer µm due to consumables and equipment depreciation @ 43 % uptime 4-8 cent per 1x1 cm die using 200 mm wafers Solar-semi coating cluster Will be optimized for PZT but can also be used for other oxides 43 % uptime = 12h/day and 6d/week
Deposition tools sputtering New hot chuck sputtering add-on for Oerlikon s Clusterline 200 II for in-situ sputtering of PZT Throughput goal 3.6 wafers/h µm (60 nm/min) on 200 mm wafers (11.000 wafers/y @ 43 % uptime) Performance goal e 31,f ~ -14 C/m 2 Deposition cost 10-20 /wafer µm due to consumables and equipment depreciation @ 43 % uptime 4-8 cent per 1x1 cm die using 200 mm wafers Oerlikon Systems Clusterline 200 II Hot chuck during sputtering 43 % uptime = 12h/day and 6d/week
In-line quality monitoring Indirect estimation of e 31,f from d 33,f and ε Needed resolution for thin films <10 pm Laser interferometry Accuracy Better 4 % of real e 31,f Throughput 10 wafers/h Automation of measurements through electrode mask layout Parameter/coefficient tracking aixacct double beam laser interferometer (aixdbli) Operations cost 4 /wafer due to equipment depreciation @ 43 % uptime aixplorer data management and analysis software
Device example fabricated by the movemems process
Chemical solution deposited PZT Deposition on 100 and 150 mm platinized wafers 200 mm in 2011 Seed layer: To obtain highly {100} oriented PZT [1] Deposited by CSD [2] PZT: Morphotropic composition; PbZr 0.53 Ti 0.47 O 3 Modified 2-methoxyethanol route [3,4] 2 µm standard thickness e 31,f ~ -14 C/m 2 @ 10 Hz ε r ~ 1200 @ 1 khz Intensity (counts) Intensity (counts) 200000 60000 50000 150000 40000 100000 30000 20000 50000 10000 {100} 2µm PZT 53/47 Sol-gel seeded (111) 0 0 8 9 10 11 12 13 14 20 25 30 35 40 45 50 Omega 2-theta (degrees) (degrees) PZT (100) rocking curve FWHM ~ 2.9 o {200} [1] N. Ledermann, P. Muralt, J. Baborowski, S. Gentil, K. Mukati, M. Cantoni, A. Seifert, and N. Setter, Sens. Actuators, A, A105, 162 (2003) [2] F. Tyholdt, F. Calame, K. Prume, W. Booij, H. Ræder, and P. Muralt, Journal of Electroceramics, 19, 311 (2007) [3] Gurkovich and Blum Ultrastruct. Process. Ceram., Glasses, Compos. (L. L. Hench and D. R. Ulrich, eds.), Wiley. NY, 1984, p. 152] [4] K. D. Budd, S. K. Dey, and D. A. Payne, British Ceramic Proceedings, 36, 107 (1985)
1600 Characterization ε r good quality indicator ε r 1400 1300 1200 1250 1000 1200 ε r 800 Mean ε r = 1204 Std. dev = 10 2 100 mm wafers with 2 µm PZT 5-10 mm 2 capacitors with regular separation. (Cr/Au top electrodes) 1150 600-150 -100-50 0 50 100 150 1100-6 -4 Electric -2 field 0(kV/cm) 2 4 6 1300 1250 Mean ε r = 1199 Std. dev = 10 Mean ε r = 1215 Std. dev = 12 Position ε r ~1200 with a variation of ~1% Measured with aixacct ε r 1200 1150 Mean ε r = 1196 Std. dev = 12 TF2000 analyzer 1100-6 -4-2 0 2 4 6 Position
Fatigue tests 2 10 7 bipolar fatigue cycles (5 10 8 ok) +/- 25 V fatigue signal 5 khz cycling frequency Before Development of remanent polarisation through the fatigue test After
The movemems process Electroceramics XII Trondheim June 13 16 th 2010
Multi project piezomems wafer Accelerometers Microfluid pumps PIMPs
16 Electroceramics XII Trondheim June 13 16 th 2010 The PiMP Piezo-Electric Micro-Piston Fabrication Spin-coat PZT Structure top electrode Structure device layer Structure backside to form membrane T. Bakke, A. Vogl, O. Żero, F. Tyholdt, I-R. Johansen and D. Wang, J. Micromech. Microeng. 20 (2010) 064010
17 Electroceramics XII Trondheim June 13 16 th 2010 PiMP my MEMS... IR filter Fabry Perot interferometer Mirror FTIR spectrometer
Fabry Perot Interferometer SOI/ PZT Si Tunable IR filter centre deflection (µm) 14 12 10 8 6 4 2 0-2 -4-6 -8 outer ring - unpoled inner ring - unpoled outer ring - poled inner ring - poled -5 0 5 10 15 20 actuation voltage (V) T. Bakke, A. Vogl, O. Żero, F. Tyholdt, I-R. Johansen and D. Wang, J. Micromech. Microeng. 20 (2010) 064010
19 Electroceramics XII Trondheim June 13 16 th 2010 Simulations Multilayer analytical model for PZT actuators agrees well with measurements Nonlinear behavior captured by finite element analysis using Comsol multiphysics Vertical deflection (µm) 5,0 4,5 4,0 3,5 3,0 2,5 2,0 1,5 1,0 0,5 Measured FEM Analytical z 0,0 0 5 10 15 20 Actuation voltage (V) multi-layered structure r R 2 R 1 neutral plane Si R in R out z p M 1 M 2 Au electrode PZT Pt electrode SiO 2 T. Bakke, A. Vogl, O. Żero, F. Tyholdt, I-R. Johansen and D. Wang, J. Micromech. Microeng. 20 (2010) 064010
Double ring design 6 4 Outerring actuated Deflection (µm) 2 0-2 0 5 10 15 20 Inner ring actuated Actuation voltage (V) -4-6
Temporal response Deflection (µm) 3 2 1 0-1 Measured response to a square wave actuation signal Resonance frequency of 9.8kHz -2-3 0,0 0,1 0,2 0,3 0,4 0,5 Time (ms)
Pure piston actuation 0V 20V
Mirror planarity 15 10 0V 20V Height (nm) 5 0-5 -10-15 0 0,5 1 1,5 2 Distance (mm) Uncoated surface: ~15 nm deformation of a 2 mm dia. mirror (<λ/40) 380µm thick mirror plate form a strong base for coatings T. Bakke, A. Vogl, O. Żero, F. Tyholdt, I-R. Johansen and D. Wang, J. Micromech. Microeng. 20 (2010) 064010
Conclusions SINTEF movemems is a standard procedure for making piezomems Design and fabrication rules Design and modelling add-on for Coventorware (Coventor) High volume capability will be added through FP7 piezovolume (2010-2013) Improving the Coventor software Sputtering/CSD tools (Oerlikon/Solar-semi) In-line quality monitoring tool for piezo thin films (aixacct) The piezoelectric Micro-piston is a very promising platform for micro IR filters and FTIR spectrometers
Acknowledgements EU FP7 for granting the piezovolume project Thank you!