Chapter 1: Lithography

Introduction

Historical Note: Lithography’s Origins

Photolithography Overview

Introduction

Masks

Spinning Resist and Soft Baking

Exposure and Postexposure Treatment

Development

De-Scumming and Postbaking

Resists

Resist Tone

Positive Resists

Negative Resists

Permanent Resists

Glass Transition Temperature of a Resist (Tg)

Wafer Priming

Wafer Cleaning and Contaminants: The Clean Room

Resist Stripping

Wet Stripping

Dry Stripping

Critical Dimension, Overall Resolution, Line-Width

Lithographic Sensitivity and Intrinsic Resist Sensitivity (Photochemical Quantum Efficiency)

Lithographic Sensitivity

Intrinsic Sensitivity of a Resist (Photochemical Quantum Efficiency)

Resist Profiles

Overview of Profile Types

Lift-Off Profile

Contrast and Experimental Determination of Lithographic Sensitivity

Resolution in Photolithography

Introduction

Resolution in Contact and Proximity Printing (Shadow Printing)

Contact Printing

Proximity Printing

Resolution with Self-Aligned Masks

Projection Printing

Introduction

Types of Projection Methods

Modulation Transfer Function

Critical MTF Values

Mathematical Expressions Governing Resolution in Projection Printing

Depth of Focus

Mask Alignment in Projection Printing

Fiducial Marks

Alignment in Miniaturized Devices

Mathematical Expression for Resist Profiles

Planarization

Introduction

Planarization Strategies

Photolithography Resolution Enhancement Technology

Introduction

Strategies for Improved Resolution through Improved Resist Performance

Chemically Amplified Resists

Introduction

tBOC Based Resists

SU-8 Resist

Summary

Image Reversal

Introduction

Rohm and Haas Resist

Antireflective Coatings –Thin Film Interference Effects

Thin Film Imaging

Thin Film Imaging in Single Layer Resist—Top Surface Imaging

Multilayer Resist Thin Film Imaging

Strategies for Improved Resolution through Improved Mask Technology

Background

Phase-Shifting Masks

Grey-Tone Masks and Tapered Structures

Beyond Moore’s Law

Introduction

Moore’s Law

Kurzweil

Next Generation Lithographies

Introduction

Extreme Ultraviolet Lithography

X-Ray Lithography

Introduction

Major Features of X-Ray Lithography

LIGA

X-Ray Resists

X-Ray Masks

Why Use a Synchrotron to Generate X-Rays?

Charged-Particle-Beam Lithography

Introduction

Electron-Beam Lithography

Overview

Electron-Beam Resists

Electron Emission Sources

Micromachined Electron Emission Sources

Scattering with Angular Limitation Projection Electron Beam Lithography (SCALPEL)

Ion-Beam Lithography

Introduction

Focused Ion Beam and Deep Ion Beam Lithography

Ion Projection Lithography

Comparison of Ion Beam Lithography with E-Beam Lithography

Emerging Lithography Technologies

Introduction

Scanning Probe Lithography

STM/AFM Background

Scanning Probe Lithography

Introduction

Modes of Pattern Generation in Scanning Probe Lithography

Atom Lithography or Mechanosynthesis

Very Thin Resist Layers

Introduction

Langmuir-Blodgett Resists

Self-Assembled Monolayers

Ultrathin Film Resist Layers

Soft Lithography

Introduction

Micro Contact Printing

Micro-Transfer Molding

Micromolding in Capillaries

Micro-Replica Molding

Soft Lithography Summary

3D Lithography Methods

Introduction

Holographic Lithography

Stereolithography/Micro-Photoforming Process

Lithography on Nonplanar Substrates

Examples

1.1 Protein Patterning

1.2 Inclined LIGA Walls

1.3 PDMS Based CDs

 

    Problems