Surface Micromachining מיקרועיבוד - משטחי

Introduction * A Short Preview FlowDesigner Surface Pressure Sensor

Fabrication Steps Details Pattern Transfer to SiO2 Buffer/Isolation Layer

Fabrication Steps Details Sacrificial Layer Deposition and Etching

Fabrication Steps Details Cont. Deposition of Structural Material * LPCVD of PolySi (25 to 150 Pa), 600 deg C * Also: Thermal Oxide, Si3Ni4 Selective Etching of Sacrificial Layer

Fabrication Steps Details Cont. Etchant – Spacer – Microstructure Combinations

MUMPs –Multi User MEMS Project A commercial fabrication process MCNC – CRONOS – JDSU - MEMSCAP MEMSCAP - MUMPS MUMPs Design Rules

Stiction * Stiction During Release Stiction After Release : In-Use Stiction – A fundamental reliability issue!

Mechanical Properties of Thin Films Adhesion

Mechanical Properties of Thin Films Cont. Stress in thin films Thermal stress

Mechanical Properties of Thin Films Cont. Stress Measuring Techniques T – Substrate thickness E – Substrate Young’ Modulus R – Radius of curvature t - Film thickness  - Poison ratio * Disk Method – Stoney Equation: * Uniaxial Measurements

Surface Micromachined Structures to Gauge Intrinsic Stress * Clamped Clamped Beams * Ring Crossbar Structures

* Vernier Gauges LS – Slope Beam Length Li – Indicator Beam Length Lt – Test Beam Length C – Correction Factor * Vernier Gauges

Cantilever Beams

Control of Film Stress

Test Structures – Microstructures Analysis Through Fabrication ISRAMEMS 2003