Electrostatic Chuck Cleaning via In-Situ Field Attraction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional manual cleaning methods for electrostatic chucks in lithography apparatuses are ineffective in removing fine particles, leading to contamination and overlay errors, and require venting and disassembly, resulting in loss of productivity and yield in chip production.

Innovation Solution

An electrostatic cleaning method using a substrate with an electrode and voltage supply to generate an electrostatic field, attracting and removing particles from the chuck surface within the vacuum environment, allowing for in-situ cleaning without disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual cleaning methods are used to clean the electrostatic chuck, then the apparatus can be disassembled and cleaned, but fine particles larger than 3 μm are removed while very fine particles remain as residue, and productivity is lost due to venting and disassembly

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidproductivity

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces manual mechanical cleaning with an electrostatic field-based cleaning system. An electrode array generates controlled electrostatic fields that attract and remove particles from the chuck surface without mechanical contact, eliminating the need for disassembly and venting while achieving superior cleaning of fine particles

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electrostatic field as an intermediary between the cleaning system and the chuck surface. This field acts as a mediator to transfer particles from the chuck to a collection surface without requiring direct mechanical intervention or system disassembly

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If manual solvent wiping is used to clean the electrostatic chuck in situ, then disassembly is avoided, but very fine particles cannot be removed effectively

Engineering Contradiction:

ImproveproductivityVSAvoidcleaning effectiveness

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical wiping with electrostatic field-based particle removal. The electrostatic field selectively attracts particles based on their size and charge characteristics, enabling effective removal of very fine particles that mechanical wiping cannot remove while maintaining in situ operation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the cleaning mechanism from mechanical force to electrostatic force by applying voltage to the electrode array. This parameter change enables the system to interact with particles through electrostatic attraction rather than mechanical contact, significantly improving the ability to remove fine particles

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If the electrostatic chuck is removed for ex situ traditional wet cleaning, then thorough cleaning can be achieved, but the chuck is electrically and mechanically integrated into a monolithic machine component making removal impossible

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidcleaning accessibility

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent extracts the cleaning function from the traditional ex situ process and integrates it directly into the in situ operational environment. The electrode array and voltage supply are positioned to clean the chuck surface while it remains installed, separating the cleaning function from the mechanical removal requirement

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes the electrostatic field generation system multi-functional by using the same electrode infrastructure that serves the electrostatic chuck operation to also perform cleaning functions. This eliminates the need for separate cleaning equipment or system disassembly

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

The method effectively removes particles from the chuck surface, preventing contamination and overlay errors, maintaining vacuum integrity and reducing downtime, thus enhancing chip production yield and productivity.

Implementation Method 1

at least one electrode configured to generate an electrostatic field between the at least one electrode and a confronting surface of a second support structure

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Implementation Method 2

attracting and removing particles from the chuck surface within the vacuum environment

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatic Induction

Data Source

PatentUS11048175B2Apparatus for and method cleaning a support inside a lithography apparatus

Publication Date: 2021.06.29 ASML HLDG NV

AI summary

Methods and systems are described for cleaning a support such as a clamp of a chuck that holds a patterning device or a wafer in a lithographic apparatus. The method includes loading a electrostatic cleaning substrate into a lithographic apparatus. The electrostatic cleaning substrate includes at least one electrode. The method further includes bringing the electrostatic cleaning substrate near to the clamping surface to be cleaned and connecting the electrode to a voltage source. Particles present on the support are then transferred to the electrostatic cleaning substrate.