Dual Directional Motor for Substrate Table Bandwidth

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Solution Overview

Problem

Conventional lithographic apparatus substrate table systems face limitations in bandwidth due to stiffness issues in motor configurations, leading to restricted acceleration and settling time, and disturbances in vacuum operations.

Innovation Solution

A substrate table system with a dual directional motor configuration, featuring first and second pusher structures that exert forces in perpendicular directions, allowing for high bandwidth movement and minimizing resonance effects, with contactless motors like Lorentz motors to decouple resonance modes and reduce material costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a Y-beam with X-motor configuration is used for substrate table positioning, then coarse positioning in X and Y directions is achieved, but the maximum bandwidth is limited by the stiffness of the Y-beam causing resonances that restrict acceleration and settling time

Engineering Contradiction:

Improvemaximum bandwidthVSAvoidresonances in Y-beam

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The substrate table positioning system is divided into two independent motor configurations: a first motor for coarse positioning in the first direction and a second motor for fine positioning in the second direction. This segmentation allows each motor to operate optimally without the resonance limitations of a single stiff Y-beam structure, thereby improving maximum bandwidth while maintaining positioning stability.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If a magnet plate with coils configuration is used for 6 degrees of freedom actuation, then operation in vacuum is enabled and positioning capability is enhanced, but disturbance forces and torques occur that propel the substrate table below its center of gravity

Engineering Contradiction:

Improveoperation in vacuumVSAvoiddisturbance forces and torques

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The harmful magnetic disturbance forces and torques are extracted and eliminated by replacing the magnet plate with coils configuration with a pusher structure and contactless motor configuration. This extraction removes the source of disturbance forces while preserving the vacuum operation capability and 6 degrees of freedom positioning capability through the alternative motor design.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The magnetic actuation system (magnet plate with coils) is replaced with a contactless motor system using pusher structures. This substitution eliminates mechanical contact and the associated disturbance forces and torques while maintaining the ability to actuate the substrate table in six degrees of freedom and operate in vacuum conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If magnets are used extensively in the substrate table system for actuation, then positioning capability is achieved, but material costs increase significantly

Engineering Contradiction:

Improvepositioning capabilityVSAvoidmagnets

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The expensive magnets are replaced with a contactless motor configuration using pusher structures and electromagnetic actuation. This substitution uses cheaper, non-magnetic materials to achieve the same positioning capability, significantly reducing material costs while maintaining full positioning functionality in both directions.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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

The dual directional motor configuration enhances the substrate table's movement bandwidth, reduces resonance-induced inaccuracies, and provides inherent safety while minimizing the need for magnets, resulting in improved performance and cost-effectiveness.

Implementation Method 1

contactless motors like Lorentz motors

Methodology Applied

Scientific EffectLorentz force: Lorentz Force

Data Source

PatentUS9753381B2Substrate table system, lithographic apparatus and substrate table swapping method

Publication Date: 2017.09.05 ASML NETHERLANDS BV

AI summary

A substrate table system includes a substrate table and a dual directional motor for moving the substrate table in a plane of movement that is defined by a first direction and a second direction. The dual directional motor includes: a first pusher structure extending in the first direction, the substrate table being movable in respect of the first pusher structure, the first pusher structure and the substrate table being arranged to cooperate to form a first motor to exert a force between the first pusher structure and the substrate table in the first direction; and a second pusher structure extending in the first direction, the substrate table being movable in respect of the second pusher structure, the second pusher structure and the substrate table to cooperate to form a second motor to exert a force between the second pusher structure and the substrate table in the second direction.