August 19, 2004 Finite Element Analysis and Design for Six Sigma Important Tools Used in Conjunction with HALT T. Kim Parnell, Ph.D.,P.E. PEC, OEI, Mike Silverman, CRE Ops A La Carte, August 19, 2004

August 19, 2004 FEA & DFSS FEA – Finite Element Analysis DFSS – Design for Six Sigma also includes: –Design sensitivity –Materials (variations) –Geometry (tolerance) –DOE – Design of Experiments –Distribution of results rather than just a single result

August 19, 2004 How do you use FEA? Finite Element Software –ANSYS –MSC.MARC, MSC.NASTRAN –ALGOR –ABAQUS –COSMOS Understanding of Loads, BCs, Materials Create the model & Run the analysis

August 19, 2004 FEA Model Creation Speaker Normal Mode Analysis Dia : 17mm Thickness : 0.016mm Mat : aluminum E : 71e9 N/m^2 v : 0.3 p : 2700 kg/m^3 Element : Shell 63 : Mass 21

August 19, 2004 FEA & DFSS Application Example: MEMS Device - Linear Resonator

August 19, 2004 Package Chip is inside package Device is on chip 19 mm 0.2 mm Quality of MEMS Devices: Linear Resonator

August 19, 2004 Device markets & Applications ABS Seatbelt restraint/ tensioning Active suspension Rollover detection Headlight leveling Joysticks Mouse Earthquake detection (gas shutoff) Electro-Mechanical Filter Quality of MEMS Devices: Linear Resonator

August 19, 2004 Multi-Physics Problem: Electromagnetic & Structure Interaction Equilibrium between electro-magnetic forces and moving comb spring back Random Input 14 different manufacturing tolerances +/- 10% Young’s Modulus +/- 10% Poisson’s Ratio +/- 10% Output Maximum Deflection Quality of MEMS Devices: Linear Resonator

August 19, 2004 One Tooth Model only geometry parameters studied Moving Comb Finger Width Moving Comb Spine Width Moving Comb Finger Thickness Only 3 out of 14 geometry parameters are important Efficiently guide the design process to product improvement Efficiently guide the quality control process Quality of MEMS Devices: Linear Resonator

August 19, 2004 Entire Resonator Model studied Entire Resonator Model geometry and material studied Very good agreement between Monte Carlo (400 FEA) and Response Surface Methods (49 FEA + 10’000 on Response Surface)Very good agreement between Monte Carlo (400 FEA) and Response Surface Methods (49 FEA + 10’000 on Response Surface) Scatter Range of “Maximum Displacement” has about a factor of 3 between lowest and largest valueScatter Range of “Maximum Displacement” has about a factor of 3 between lowest and largest value Quality of MEMS Devices: Linear Resonator

August 19, 2004 Very good agreement between Monte Carlo (400) and Response Surface Methods (49) Results enable a “Design for Reliability” (lower scrap rate, lower quality control cost, lower warranty costs) Quality of MEMS Devices: Linear Resonator

August 19, 2004 Monte Carlo (400) Response Surface Methods (49) Very good agreement between Monte Carlo (400) and Response Surface Methods (49) Same 3 geometry parameters and Young’s Modulus are important More efficiently guide the design process to product improvement Efficiently guide the quality control process Efficiently guide and justify lab test spending Quality of MEMS Devices: Linear Resonator

August 19, 2004 FEA & DFSS Application Example: Cell Phone Drop Test

August 19, 2004 Random Input Drop Height Inclination angle Horizontal angle Densities … Output Maximum Stress Reliability of Electronic Devices: Dropping of a Cell Phone

August 19, 2004 Most Probable Scenarios Wide range of results (ratio ~ 60), single deterministic run will not cover the real scenario Reliability of Electronic Devices: Dropping of a Cell Phone

August 19, 2004 More efficiently guide the design process to product improvement Efficiently guide the quality control process Efficiently guide and justify lab test spending Reliability of Electronic Devices: Dropping of a Cell Phone

August 19, 2004 Summary Finite Element Analysis (FEA) and Design for Six Sigma (DFSS) techniques are both useful tools in their own right. They provide valuable insights and guidance when used in conjunction with a HALT program. Use them at both the front end (pre-HALT) and the back end (post-HALT).