Convex Cleaning Substrate for Reticle Clamp Contamination Removal

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Solution Overview

Problem

The existing cleaning methods for photolithographic apparatuses require downtime for manual cleaning and chemical wet cleaning, which can lead to contamination transfer and defects in pattern transfer to wafers, necessitating an in-situ cleaning solution that avoids these limitations.

Innovation Solution

A cleaning substrate with an upward or convex curve is used to apply greater mechanical force for effective cleaning of the reticle clamp's working surface, allowing for in-situ removal of contaminants without damaging the components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual cleaning or chemical wet cleaning is used to clean the reticle clamp, then contamination is removed, but production downtime increases and contamination may transfer to the patterning device

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidproduction downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The cleaning substrate is designed to be self-contained with integrated cleaning elements (elastomeric material with abrasive particles or porous structure with cleaning agents) that enable the reticle clamp to clean itself during normal operation without requiring external cleaning interventions, thereby eliminating production downtime while maintaining effective contamination removal

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The cleaning substrate is pre-prepared with cleaning functionality (embedded abrasive particles, porous structure filled with cleaning agents, or elastomeric material with embedded contaminants) before contact with the reticle clamp, allowing immediate cleaning action upon contact without requiring additional preparation steps that would cause downtime

Inventive Principle:

Principle #10Preliminary action

2Reliability

If chemical wet cleaning is used to remove contamination, then cleaning effectiveness is achieved, but contamination may transfer to the patterning device and cause defects

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidcontamination transfer

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention replaces chemical wet cleaning with a mechanical cleaning mechanism where a cleaning substrate with elastomeric material and embedded abrasive particles physically removes contamination through friction and adhesion forces, eliminating the risk of chemical contamination transfer to the patterning device while maintaining effective cleaning

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cleaning substrate is designed as a disposable or easily replaceable component that accumulates contamination during cleaning operations and is then discarded or regenerated, preventing the transfer of cleaned contaminants back to the reticle clamp or patterning device, unlike reusable chemical cleaning systems that may redistribute contaminants

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If the cleaning substrate has a flat surface, then manufacturing is simpler, but mechanical force application to the reticle clamp interface is insufficient for effective cleaning

Engineering Contradiction:

Improvesubstrate manufacturing simplicityVSAvoidmechanical cleaning force

Core Design Contradiction:

Ease of manufactureVSForce

Solution Approach 1:

The cleaning substrate incorporates a convex curved surface instead of a flat surface, which concentrates the contact area with the reticle clamp and increases the mechanical force density at the interface, thereby enhancing cleaning effectiveness while the curvature can be achieved through standard forming processes that maintain manufacturing feasibility

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 enables efficient in-situ cleaning of the reticle clamp, reducing downtime and preventing contamination transfer, thereby improving the reliability and quality of pattern transfer in photolithographic processes.

Implementation Method 1

The cleaning substrate is provided with an upward or convex curve (middle higher than the periphery) so that greater mechanical force can be applied to an interface between the cleaning substrate and a reticle clamp to promote cleaning of the working surface of the reticle clamp

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS20240419089A1Apparatus for and method of lithography support cleaning

Publication Date: 2024.12.19 ASML HLDG NV

AI summary

Apparatus for and method of removing a contaminant from a working surface of a lithography support such as a reticle or wafer stage in an EUV or a DUV photolithography system in which a base supporting the substrate is provided with a surface profile so as to be thicker towards a middle portion of the base so that when a substrate supported by the base is pressed between the working surface and the base the contaminant is transferred from the working surface to the substrate.