Electron Beam Lithography Dummy Patterns for Higher Throughput

Solution Overview

Problem

The throughput of charged particle beam lithography systems is limited by the time required to expose an entire workpiece, which constrains their usefulness for mass fabrication, especially as integrated circuit technologies progress towards smaller feature sizes.

Innovation Solution

The implementation of an electron beam lithography system that increases pattern density to enhance backscattered energy, reducing the maximum exposure dose needed for proximity effect correction, thereby increasing scanning speed and improving throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the exposure dose is increased to maintain image contrast in low-density pattern areas, then the manufacturing precision is improved, but the throughput decreases due to longer exposure time

Engineering Contradiction:

Improveimage contrastVSAvoidthroughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

Dummy patterns are inserted into the design layout before the actual lithography exposure process. These dummy patterns pre-establish a more uniform pattern density distribution across the wafer, ensuring that low-density areas have sufficient backscattered electron energy to maintain image contrast without requiring excessive exposure doses, thereby resolving the contradiction between manufacturing precision and throughput

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the pattern density parameter by adding dummy patterns, which alters the backscattered electron energy distribution. This parameter change enables uniform exposure conditions across different pattern density regions, allowing the system to maintain image contrast at lower exposure doses and thus improve throughput while preserving manufacturing precision

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the scanning speed is increased to improve throughput, then the productivity is improved, but the exposure dose requirements increase to maintain image contrast

Engineering Contradiction:

ImprovethroughputVSAvoidexposure dose

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

Dummy patterns are inserted into the design layout before the actual lithography exposure process. These dummy patterns pre-establish a more uniform pattern density distribution across the wafer, ensuring that low-density areas have sufficient backscattered electron energy to maintain image contrast without requiring excessive exposure doses, thereby resolving the contradiction between manufacturing precision and throughput

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the pattern density parameter by adding dummy patterns, which alters the backscattered electron energy distribution. This parameter change enables uniform exposure conditions across different pattern density regions, allowing the system to maintain image contrast at lower exposure doses and thus improve throughput while preserving manufacturing precision

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for faster exposure of workpieces while maintaining image contrast and uniformity across various pattern densities, enhancing the efficiency of the electron beam lithography process.

Implementation Method 1

increases pattern density to enhance backscattered energy, reducing the maximum exposure dose needed for proximity effect correction

Methodology Applied

Scientific EffectBackscattered energy: Scattering

Data Source

PatentUS11899367B2Dummy insertion for improving throughput of electron beam lithography

Publication Date: 2024.02.13 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An electron beam lithography system and an electron beam lithography process are disclosed herein for improving throughput. An exemplary method for increasing throughput achieved by an electron beam lithography system includes receiving an integrated circuit (IC) design layout that includes a target pattern, wherein the electron beam lithography system implements a first exposure dose to form the target pattern on a workpiece based on the IC design layout. The method further includes inserting a dummy pattern into the IC design layout to increase a pattern density of the IC design layout to greater than or equal to a threshold pattern density, thereby generating a modified IC design layout. The electron beam lithography system implements a second exposure dose that is less than the first exposure dose to form the target pattern on the workpiece based on the modified IC design layout.