Chapter 2: Pattern Transfer with Dry Etching Techniques

Introduction

Dry Etching: Definitions and Jargon

Plasmas or Discharges

Physics of DC Plasmas

Spatial Zones in the Glow Discharge

Paschen’s Law

Physics of RF Plasmas

Physical Etching: Ion Etching or Sputtering and Ion-Beam Milling

Introduction

Sputtering or Ion Etching

Ion-Beam Etching or Ion-Beam Milling

Etching Profiles in Physical Etching

Introduction

Faceting Due to Angle-Dependent Sputter Rate

Ditching or Trenching

Redeposition

Backscattering

Angular Distribution of Incident Ions

Physical Etching Summary

Plasma Etching (Radical Etching)

Introduction

Reactor Configurations

Reaction Mechanism

Loading Effects—Uniformity and Nonuniformity

Atmospheric Downstream Plasma Etching or Plasma Jet Etching

Ion Energy versus Pressure Relationship in a Plasma

Physical/Chemical Etching

Introduction

Energy-Driven Anisotropy

Inhibitor-Driven Anisotropy

Dopant Driven Anisotropy

Gas Compositions in Dry Etching

Simplifying Rules

Deep Reactive Ion Etching (DRIE)

Introduction

New Plasma Sources

Inductively Coupled Plasma

Electron Cyclotron Resonance

Common Problems Associated with DRIE

Silicon Grass or Black Silicon

Microloading

Vapor-Phase Etching without Plasma (XeF₂)

Dry Etching Models—In Situ Monitoring

Comparing Wet and Dry Etching

Examples

2.1 Via Etching in Si

2.2 Single Crystal Reactive Etching and Metallization (SCREAM)

2.3 Post-CMOS Processing for High-Aspect-Ratio Integrated Silicon Microstructures

2.4. Dry Etching of Polymeric Materials

2.5. Combination Wet and Dry Etching

Problems