Your SlideShare is downloading. ×
Mems accelerometer designing and fabrication
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Mems accelerometer designing and fabrication

2,427
views

Published on

Design,fabrication and Application of MEMS accelerometer.

Design,fabrication and Application of MEMS accelerometer.

Published in: Education, Technology, Business

0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
2,427
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
211
Comments
0
Likes
3
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. MEMS CAPACITIVE ACCELEROMETER (Design and Fabrication) Presented by:- PRASHANT SINGH
  • 2. OUTLINE  Introduction  MEMS         Accelerometer Basic operation principle Capacitive Accelerometer   MEMS vs. IC’s Capacitance basics Sensing mechanism Structure analysis (spring stiffness) Advantages Accelerometer fabrication Applications
  • 3. INTRODUCTION  MEMS    MEMS:    MEMS move and Sense Mass. MEMS act as transducer (Sensor & Actuator). IC    Micro-Electro-mechanical-system Integration of mechanical unit, electrical unit, sensor and actuator on a single substrate. IC’s move & sense electrons. IC’s acts as sensor not actuator. MEMS Advantage    Smaller Lighter Economical
  • 4. ACCELEROMETER  Inertial sensor:   Device used to measure:      Newton’s 1st law (Mass of inertia). Acceleration Displacement Force Inclination Design Approach:     Piezoelectric Piezoresistive Tunneling Capacitive, etc. Basic capacitive Accelerometer.
  • 5. BASIC OPERATION PRINCIPLE 
  • 6. CAPACITIVE ACCELEROMETER     Based on Change in capacitance between Comb fingers. {Capacitance change} α {Force applied on Proof Mass} Comb structure Large capacitance value Advantages      High resolution Good DC response Linear output low power dissipation Easy incorporation with CMOS
  • 7. CAPACITANCE BASICS 
  • 8. SENSING MECHANISM  (a) Two types:  Out-of-Plane Sensing  Change  in overlapping width (w). In-Plane sensing  Lateral  sensing (a) Change in overlapping length (L)  Transverse  sensing (b) Change in finger gap (d) (b)
  • 9. STRUCTURE ANALYSIS  Unguided and guided beam structure
  • 10. CAPACITIVE ACCELEROMETER ADVANTAGES High sensitivity.  Easy readout circuitry.  Independent of temperature variation.  Easy fabrication (two level mask).  Large noise margin.  Fabrication on silicon.  Compatible with CMOS technology. 
  • 11. FABRICATION PROCESS  Silicon on insulator(SOI) wafer(i) 15µm 2µm  Cleaning -RCA 1 -RCA 2  Oxidation(ii)   475 µm thickness of oxide layer ::7700 Å at 1050ºC Photolithography(iii) -1st level mask -prebaking -UV light exposer-15 sec -PR develop silicon oxide silicon oxide silicon oxide (i) (ii) silicon oxide photoresist Silicon oxide silicon oxide (iii)
  • 12. FABRICATION PROCESS CONTD..  SiO2 etch (iv) –buffer HF -etch rate ≈ 1000Å/min.  Silicon etch(v) Silicon oxide silicon oxide (iv oxide -PR removal -Anisotropic Si etch -THAH solution used -V groove formation oxide silicon oxide (v
  • 13. FABRICATION PROCESS CONTD..  SiO2 removal (vi) -Buffer HF -hanging structure  oxide (vi silicon Metallization (vii) -2nd level mask -Al deposited -temp. 650ºC oxide silicon (vi
  • 14. ACCELEROMETER FABRICATION CONTD..  Accelerometer (1st level mask, PR developed) photoresist  Accelerometer (SiO2 etched) SiO2 Si SiO2 Si
  • 15. APPLICATIONS  Automotive   Consumer Electronics     hard disk protection(laptops) screen rotation (mobile) Image stabilization (camera) Industrial    Crash detection & Air bag deployment. Vibration detection (machine) crack detection (pulley) Aerospace & Defence    Navigation Missile guidance Thrust detection Accelerometer application
  • 16. THANK YOU