Magnetic Stage Floating in Lithography Linear Motors

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Solution Overview

Problem

Conventional stage driving apparatuses with linear motors face challenges in floating the stage relative to the stator without contaminating substrates due to particle scattering during gas blowing, which affects the cleanliness and accuracy of substrate processing.

Innovation Solution

A stage driving apparatus is designed with a linear motor configuration that includes a stator with arrayed coils and a mover equipped with a permanent magnet and an electromagnet, where the stator has a yoke member to cover the electromagnet side, allowing the controller to control energization to generate a floating force and orient the stage, reducing the need for additional bearing mechanisms and minimizing particle scattering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gas blowing mechanism is used to float the stage, then the stage can be floated relative to the stator, but particles are scattered and contaminate the substrate

Engineering Contradiction:

Improvestage floating capabilityVSAvoidparticle contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the gas blowing mechanism entirely and replaces it with a magnetic field-based floating system using permanent magnets and electromagnets. This extracts the harmful gas blowing function while retaining the essential stage floating capability through magnetic repulsion and attraction forces.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the pneumatic system (gas blowing) with an electromagnetic system. The stage is floated by controlling the interaction between permanent magnets attached to the stage and electromagnets on the stator, substituting mechanical/pneumatic action with electromagnetic forces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a separate floating mechanism is added to the linear motor, then the stage can be floated, but the device complexity increases

Engineering Contradiction:

Improvestage floating capabilityVSAvoidmechanism arrangement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the floating function with the linear motor structure by integrating permanent magnets into the mover and electromagnets into the stator. This combination eliminates the need for separate floating mechanisms while maintaining both driving and floating capabilities within a unified system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electromagnetic components serve dual purposes: the permanent magnets and coils provide both linear driving force and magnetic repulsion for floating, while electromagnets provide both driving force and controlled magnetic attraction for floating. This multi-functionality reduces overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration effectively floats the stage relative to the stator, reducing contamination risks and improving the cleanliness and accuracy of substrate processing, while also allowing for simpler and lighter construction of the stage driving apparatus.

Implementation Method 1

the mover includes a permanent magnet provided on one of an upper side and a lower side of the plurality of coils, and an electromagnet provided on the other of the upper side and the lower side of the plurality of coils

Methodology Applied

Scientific EffectMagnetic force: Magnetism

Implementation Method 2

the controller controls driving of the stage in the driving direction while floating the mover relative to the stator by controlling energization to the plurality of coils and the electromagnet

Methodology Applied

Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 3

a linear motor including a stator having a plurality of coils arrayed along a driving direction of the stage, and a mover provided with the stage

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentUS11543745B2Stage driving apparatus, lithography apparatus, and method of manufacturing article

Publication Date: 2023.01.03 CANON KK

AI summary

The present invention provides a stage driving apparatus for driving a stage, the apparatus comprising: a linear motor including a stator having a plurality of coils arrayed along a driving direction of the stage, and a mover provided with the stage; and a controller configured to control the linear motor, wherein the mover includes a permanent magnet provided on one of an upper side and a lower side of the plurality of coils, and an electromagnet provided on the other, the stator includes a yoke member provided to cover the electromagnet side of the plurality of coils, and the controller controls driving of the stage in the driving direction while floating the mover relative to the stator by controlling energization to the plurality of coils and the electromagnet.