Electron Beam Welding for Lithographic Actuator Cooling Bodies

Solution Overview

Problem

Conventional electromagnetic actuators in lithographic apparatuses face accuracy issues due to temperature increases from electric current dissipation, limiting the force they can apply, and the welding method used to connect cooling bodies is prone to failure under oscillating and pressure loads.

Innovation Solution

A method of radiation beam welding is employed to connect first and second members of an electromagnetic actuator, forming a continuous transition at the periphery of a recess to enhance the structural integrity and reduce thermal stress, using a first member with a recess and a second member with a complementary surface to create a weld with a recess side facing inward, thereby forming a continuous transition between the members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If laser beam welding is used to connect the two plates of the cooling body, then the manufacturing process is simple and efficient, but the welding seam cannot withstand high oscillating and pressure loads

Engineering Contradiction:

Improvewelding process simplicityVSAvoidwelding seam load capacity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the welding parameters by using electron beam welding instead of laser beam welding, altering the energy delivery method, vacuum environment requirements, and beam control parameters to achieve superior weld strength capable of withstanding oscillating and pressure loads

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the laser beam welding system with an electron beam welding system, replacing optical energy delivery with kinetic electron energy delivery to create stronger welds in the cooling body plates

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If conventional laser beam welding is used, then the manufacturing process is straightforward, but the welding seam is prone to failure under oscillating loads from the actuator driving cycle

Engineering Contradiction:

Improvewelding process simplicityVSAvoidwelding seam resistance to oscillating loads

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the welding parameters by using electron beam welding instead of laser beam welding, altering the energy delivery method, vacuum environment requirements, and beam control parameters to achieve superior weld strength capable of withstanding oscillating and pressure loads

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the laser beam welding system with an electron beam welding system, replacing optical energy delivery with kinetic electron energy delivery to create stronger welds in the cooling body plates

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional laser beam welding is used, then the manufacturing process is simple, but the welding seam cannot withstand high pressure loads from cooling liquid pumping

Engineering Contradiction:

Improvewelding process simplicityVSAvoidwelding seam pressure load capacity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the welding parameters by using electron beam welding instead of laser beam welding, altering the energy delivery method, vacuum environment requirements, and beam control parameters to achieve superior weld strength capable of withstanding oscillating and pressure loads

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the laser beam welding system with an electron beam welding system, replacing optical energy delivery with kinetic electron energy delivery to create stronger welds in the cooling body plates

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

The method allows the cooling system to withstand higher loads and reduces thermal stress, enabling the actuators to maintain accuracy and apply greater forces without cracking, with experimental results showing the weld can withstand up to three times the stress of prior art welds.

Implementation Method 1

directing the radiation beam towards the second surface portion such that the first and second member are welded together at the periphery of the recess

Methodology Applied

Scientific EffectRadiation beam welding: Laser Beam Welding

Implementation Method 2

the actuators may be cooled using cooling bodies with cooling channels around the electric current carrier thereby removing the dissipated heat

Methodology Applied

Scientific EffectHeat removal through cooling channels: Convection

Implementation Method 3

the electric current running through the electric current carrier dissipates a lot of energy thereby increasing the temperature

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS9409251B2Radiation beam welding method, body and lithographic apparatus

Publication Date: 2016.08.09 ASML NETHERLANDS BV

AI summary

A method for radiation beam welding of a first member to a second member of a cooling body for an electromagnetic actuator. The first member on a side thereof comprises a surface portion provided with a recess, which is delimited by a periphery, and wherein the second member comprises a substantially continuous first surface portion complementary to the surface portion of the first member in order to close off the recess, the second member being provided with a second surface portion opposite to the first surface portion. The method comprising arranging the first and second member such that the first surface portion engages with the surface portion of the first member; providing a radiation beam, directing the radiation beam towards the second surface portion such that the first and second member are welded together at the periphery of the recess.