1 Nanotech Project 2008 / Phase 2 Project: Team: ACCOTO Celso ADHAM Mohamed LARRIEU JeanCharles LE GROS Christophe MAQUEDA LÓPEZ Mariazel OTTONELLO BRIANO Floria PIZZATO Daniel SADRINI Jury Team Members: Interferometric Modulator Display Presentation 3: Anatomy of an iMod

2 Nanotech Project 2008 / Phase 2 Project: Team: Introduction What? A new display technology, using MEMS How? Fabry-Pérot MEMS optical switch (iMod) Capacitive, Bi-stable Why? Low Power, daylight viewing Its “cool” Agenda: 1.Control 2.Simulation 3.Fabrication

3 Nanotech Project 2008 / Phase 2 Project: Team: Block Diagram of a System with a Display Source: Texas Instruments

4 Nanotech Project 2008 / Phase 2 Project: Team: Display’s Power IC 5’’- 9’’ Display 800 x 240 px 1600 x 1200 px 5’’- 9’’ Display 800 x 240 px 1600 x 1200 px ESD – EMI Filters DC/DC Boost converter ESD – EMI for robustness/reliability (EMC immunity)  Battery voltage: 3.75V Portable Display Architecture

5 Nanotech Project 2008 / Phase 2 Project: Team: Pixel Addressing Mechanisms  Addressing refers to the mechanism by which pixels are turned on and off 1.Direct Addressing: requires a dedicated control line-driver for every pixel 2. Multiplexed Addressing: each pixel no longer needs a dedicated circuit Large number of pixels can be addressed: line-column address significantly reducing the complexity of the circuit

6 Nanotech Project 2008 / Phase 2 Project: Team: IMOD Pixel Addressing: Multiplexed addressing  Source: “Operating Principle of IMOD” White paper from Qualcomm  Pixels arranged in a rectangular matrix

7 Nanotech Project 2008 / Phase 2 Project: Team: IMOD Pixel Addressing: Creating Colors 3 Colors, 12 Binary iMods of each Red, Green and Blue 3 Colors, 12 Binary iMods of each Red, Green and Blue Translates into 13 intensity levels for each of the 3 primary colors Translates into 13 intensity levels for each of the 3 primary colors Therefore, 12^3 intensity color levels Therefore, 12^3 intensity color levels MATLAB simulation

8 Nanotech Project 2008 / Phase 2 Project: Team: Physics of Modelling Quasi 2-D Model Quasi 2-D Model 2-D: because many points are considered 2-D: because many points are considered Quasi: because only the vertical displacement is taken into account Quasi: because only the vertical displacement is taken into account

9 Nanotech Project 2008 / Phase 2 Project: Team: MATLAB Simulation

10 Nanotech Project 2008 / Phase 2 Project: Team: Physics of Modelling Forces considered in the model 1.Bending Force 2.Stretch Force 3.Damping Force

11 Nanotech Project 2008 / Phase 2 Project: Team: Physics of Modelling Forces considered in the model 4.Electrostatic 5.Residual Stress Force 6.Contact Force

12 Nanotech Project 2008 / Phase 2 Project: Team: Real Model

13 Nanotech Project 2008 / Phase 2 Project: Team: Improving the Design Change physical design Change physical design Modify back electrode Modify back electrode Material Material More compliant materials More compliant materials Thickness Thickness Thinner back plate (technology issue) Thinner back plate (technology issue) Length Length Resolution is a constraint Resolution is a constraint Boost V Boost V Low power constraint Low power constraint

14 Nanotech Project 2008 / Phase 2 Project: Team: ANSYS Design Single IMOD model 1 pixel IMOD model

15 Nanotech Project 2008 / Phase 2 Project: Team: ANSYS Design + improves compliance - more complex process + reduces pull in voltage - signal integrity - stress issues - stress issues

16 Nanotech Project 2008 / Phase 2 Project: Team: Process Flow Glass Substrate Sputter: Al, Au, Ag Deposition: PMMA Deposition: PMMA Photolithography (Exposition) Selective Removal Deposition: SiO2 Deposition: SiO2 Photolithography + Etching Photolithography + Etching Deposition: PolySilicon Deposition: PolySilicon Deposition: Aluminum Membrane Deposition: Aluminum Membrane Lift Off Wet Etching (SiO2) Wet Etching (SiO2)

17 Nanotech Project 2008 / Phase 2 Project: Team: Conclusion Wide variety of colors will be available Wide variety of colors will be available Initial simulations indicate that our initial design is not suitable Initial simulations indicate that our initial design is not suitable Redesign parameters have been outlined, and simulation is underway Redesign parameters have been outlined, and simulation is underway Initial fab process has been defined, and material selection will be an iterative process with simulation Initial fab process has been defined, and material selection will be an iterative process with simulation Challenges: Chicken and egg problem of design Challenges: Chicken and egg problem of design

18 Nanotech Project 2008 / Phase 2 Project: Team: Thank you for your attention, Questions? References: Texas Instruments website, Block Diagrams, LCD Digital Texas Instruments website, Block Diagrams, LCD Digital Operation of an iMod, Whitepaper, QUALCOMM MEMS Technologies Operation of an iMod, Whitepaper, QUALCOMM MEMS Technologies Chan E, Characterization and modeling of electrostatically actuated polysilicon micromechanical devices, Thesis, Stanford University Chan E, Characterization and modeling of electrostatically actuated polysilicon micromechanical devices, Thesis, Stanford University