1. Assignment#01: Literature Survey on Sensors and Actuators ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Electrostatic Microactuators Prepared by: Rajesh Kamatanam Dept. of Electrical and Computer Engineering Utah State University E :rajesh.kamatanam@gmail.com; T: (404)509- 9060 3/11/2005

2. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-2 Outline –Reference list –To Explore Further –Major Applications –Types of Electrostatic MAs –Working –Fabrication –Some Pictures –A Typical Example –Limitations –Manufacturers

3. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-3 Reference list 1.Travel Range Extension of a MEMS Electrostatic Microactuator by D Piyabongkarn, Y Sun, R Rajamani, A Sezen, and B J Nelson. IEEE Transactions on Control Systems Technology, Vol. 13, No. 1, January 2005Travel Range Extension of a MEMS Electrostatic Microactuator by D Piyabongkarn, Y Sun, R Rajamani, A Sezen, and B J Nelson. IEEE Transactions on Control Systems Technology, Vol. 13, No. 1, January 2005 2.A DRIE Comb-Drive Actuator With Large, Stable Deflection Range for Use as an Optical Shutter by John D. Grade, Kevin Y. Yasumura, and Hal Jerman, Iolon, Inc., San Jose, CA, USAA DRIE Comb-Drive Actuator With Large, Stable Deflection Range for Use as an Optical Shutter by John D. Grade, Kevin Y. Yasumura, and Hal Jerman, Iolon, Inc., San Jose, CA, USA 3.University of Minnesota, MinneapolisUniversity of Minnesota, Minneapolis 4. Micromanipulation with Cilia ArraysMicromanipulation with Cilia Arrays 5. Mechatronics of Electrostatic Microactuators for Computer Disk Drive Dual- Stage Servo Systems by Yunfeng Li and Roberto Horowitz. IEEE/ASME Transactions on Mechatronics, Vol. 6, No. 2, June 2001Mechatronics of Electrostatic Microactuators for Computer Disk Drive Dual- Stage Servo Systems by Yunfeng Li and Roberto Horowitz. IEEE/ASME Transactions on Mechatronics, Vol. 6, No. 2, June 2001

4. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-4 To Explore Further This presentation gives a brief idea about electrostatic microactuators. So if you want to know more about this topic, you can try searching IEEE Xplore where you can find about current research going in this field. IEEE Xplore Another type of MEMS actuator is electromagnetic microactuators. You may also want to explore them.explore

5. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-5 Major applications Optical switching Hard disk drive head motion Manipulation of subcellular structures within biological cells Microassembly of hybrid MEMS devices Manipulation of large molecules such as DNA or proteins

6. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-6 Types of Electrostatic MAs Comb-drive Parallel-plate

7. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-7 Working 1 The actuation principle behind parallel-plate electrostatic microactuators is the attractive force of two oppositely charged plates by applying a voltage between them.

8. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-8 Working (cont.) 1

9. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-9 Working (cont.) 1 The comb-drive-type electrostatic microactuator has a large numbers of fine interdigitated “fingers” to generate the actuated force. A comb drive that is actuated by a parallel-plate field at each finger pair is called a “transverse” comb drive. The movable plate and movable finger are suspended by mechanical elastic members.

10. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-10 Working (cont.) 1 Solid model of a two axis microactuator:

11. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-11 Working (cont.) 1 One axis comb drive model (offset):

12. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-12 Working (cont.) 1 In the above figure x is the displacement of the movable fingers from the equilibrium position. This comb drive is said to be “offset” since the distance x 1 is much smaller than the distance x 2. Each gap between adjacent fingers has a specific capacitance.

13. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-13 Working (cont.) 1 For instance, C 1 and C 2 can be calculated by the following: where K d = dielectric constant for the material, ε = permittivity of free space, and A = overlapping area of each finger pair.

14. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-14 Working (cont.) 1 The electrostatic force on the movable comb fingers is given by where N = number of parallel capacitor pairs, and V = applied actuation voltage.

15. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-15 Fabrication 2 The following slides show the fabrication process of an electrostatic microactuator for optical shutter (shown below) application.

16. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-16 Fabrication (cont.) 2 Etch shallow cavity in carrier wafer to create future movable areas.

17. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-17 Fabrication (cont.) 2 Fusion bond device wafer to carrier; polish to final thickness.

18. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-18 Fabrication (cont.) 2 Oxidize; open contact holes; deposit and pattern pad holes.

19. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-19 Fabrication (cont.) 2 DRIE (deep reactive ion etching) etch through device wafer.

20. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-20 Some Pictures 3 A close up of an electrostatic microactuator

21. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-21 Some Pictures (cont.) 4 A cut section of an organic thermal and electrostatic microactuator:

22. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-22 A Typical Example 5 IBM’s electrostatic microactuator mounted on an integrated lead suspension of hard disk drive head:

23. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-23 A Typical Example (cont.) 5 IBM’s electrostatic microactuator parameters: Resonance frequency: 1.5 kHz +/-15% Damping coefficient: 0.015 Stroke limit: +/- 1 µm Gain: 2 G/V Maximum voltage: +/-40V

24. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-24 Limitations Apart from advantages of high performance and low cost, these microactuators have some limitations also: In parallel-plate type microactuators, the force output is highly nonlinear over stroke range and may become unstable under large actuation voltages. Electrical isolation is another problem in parallel- plate microactuators.

25. 5/5/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-25 Manufacturers The major manufacturers of electrostatic microactuators are: IBM Corporation ST Microelectronics Agilent Technologies