Lithographic Radiation Beam Inspection via Moveable Mirror

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Solution Overview

Problem

Conventional lithographic processes face challenges in accurately predicting and achieving desired patterns on substrates due to diffraction effects, requiring time-consuming and expensive iterative procedures to correct for spurious artifacts, especially when operating near the resolution limit.

Innovation Solution

A lithographic apparatus and method that includes an illumination system, patterning device, projection system, and radiation inspection device, allowing for the modulation and inspection of radiation beams to optimize pattern exposure on substrates, minimizing differences between desired and actual patterns without the need for repeated substrate processing and reticle manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional lithographic processes operate near the resolution limit to form smaller pattern features, then manufacturing precision is improved, but spurious artifacts appear due to diffraction effects

Engineering Contradiction:

Improvepattern feature sizeVSAvoidspurious artifacts

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by inspecting the radiation beam pattern before it is projected onto the substrate. The inspection device detects spurious artifacts in advance, allowing corrections to be made to the patterning device or beam conditions prior to actual substrate exposure, thereby eliminating artifacts without requiring iterative substrate processing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the inspection device to monitor the radiation beam pattern and feed this information back to the control system. This enables real-time adjustment of the patterning device or beam parameters to compensate for diffraction effects and eliminate spurious artifacts, improving manufacturing precision while operating near the resolution limit

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If iterative procedures are used to correct for spurious artifacts by repeating substrate processing and reticle manufacturing, then manufacturing precision is improved, but loss of time and cost increase

Engineering Contradiction:

Improvepattern accuracyVSAvoiditerative correction time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent uses a radiation beam inspection device that creates an optical copy or image of the radiation beam pattern before it reaches the substrate. This allows inspection and measurement of the beam characteristics without physically exposing substrates or manufacturing reticles, enabling rapid iteration and correction of patterns without time-consuming physical manufacturing cycles

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The inspection device acts as an intermediary between the patterning device and the substrate. It measures the actual radiation beam pattern in advance, providing information that can be used to correct the patterning device settings before actual exposure, thereby eliminating the need for iterative substrate processing and reticle manufacturing

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If simulation techniques are used to predict spurious effects, then device complexity is reduced, but measurement precision is insufficient

Engineering Contradiction:

Improveprediction model complexityVSAvoidspurious effect prediction accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces complex computational simulation techniques with a direct physical measurement approach. Instead of using computer models to predict spurious effects, the inspection device directly measures the radiation beam pattern and diffraction effects in the optical path, providing accurate data without requiring complex prediction algorithms or extensive computational resources

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables precise optimization of radiation patterns on substrates with reduced time and cost, allowing for more efficient and accurate pattern formation without the need for iterative corrections and reticle revisions.

Implementation Method 1

a radiation inspection device (10) which inspects at least a part of the modulated beam of radiation (B)

Methodology Applied

Scientific EffectRadiation detection: Photoelectric Effect

Data Source

PatentUS8937705B2Lithographic apparatus and device manufacturing method with radiation beam inspection using moveable reflecting device

Publication Date: 2015.01.20 ASML NETHERLANDS BV

AI summary

A lithographic apparatus can include the following devices: a patterning system, a projection system, and a radiation beam inspection device. The patterning system can be configured to provide a patterned radiation beam. The projection system can be configured to project the patterned radiation beam onto a target portion of a substrate. Further, the radiation beam inspection device can be configured to inspect at least a part of the patterned radiation beam. In a substrate exposure position, the projection system is configured to expose a pattern of radiation on the substrate using the patterned radiation beam and the radiation beam device is configured to move the reflecting device away from a light path of the patterned radiation beam. In a radiation beam inspection position, the radiation beam inspection device is configured to move the reflecting device into the light path of the patterned radiation beam.