Reticle Cleaner With Deformable Sticky Layer

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Solution Overview

Problem

The existing methods for cleaning photomasks and EUV masks are inefficient, requiring long times and high costs due to the need to remove and reattach pellicles, and can cause pattern distortion from foreign particles, leading to reduced operating rates in semiconductor manufacturing.

Innovation Solution

A reticle cleaner with a recessed design and a deformable sticky layer support board that uses gas supply and exhaust holes to attach and detach a sticky layer from the reticle, allowing for particle removal without pellicle peeling, and can operate in a controlled vacuum environment to prevent air bubbles and particle reattachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pellicle is removed and reattached for cleaning the reticle, then particles can be removed from the reticle surface, but the pattern may be damaged and the cleaning process takes a long time

Engineering Contradiction:

Improvepattern integrityVSAvoidcleaning time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

A sticky layer is introduced as an intermediary between the reticle surface and the cleaning mechanism. The sticky layer selectively adheres to particles while allowing the pellicle to remain intact, enabling particle removal without direct mechanical contact that could damage the pattern or require pellicle removal.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical process of peeling and reattaching the pellicle is replaced by a chemical/adhesive-based approach where the sticky layer bonds to particles. This substitution eliminates the need for mechanical manipulation of the pellicle, reducing both time and damage risk.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the pellicle is removed and reattached for cleaning the reticle, then particles can be removed from the reticle surface, but the cost increases due to pellicle replacement

Engineering Contradiction:

Improveparticle removal effectivenessVSAvoidpellicle cost

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The sticky layer serves as a consumable intermediary that captures particles while leaving the expensive pellicle intact. This approach transfers the cost from permanent pellicle replacement to disposable sticky layer material, reducing overall substance loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sticky layer is designed as a disposable, low-cost component that performs the particle capture function. By using a cheap, replaceable layer instead of replacing the expensive pellicle, the loss of substance cost is significantly reduced.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If cleaning is performed on the EUV mask to remove foreign particles, then particle contamination is reduced, but foreign particles may be reattached to the patterned surface requiring additional testing

Engineering Contradiction:

Improveforeign particle managementVSAvoidoperating rate

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The sticky layer acts as a mediator that captures foreign particles during the cleaning process, preventing them from being reattached to the patterned surface. This selective adhesion ensures particles are removed without causing new contamination, eliminating the need for additional foreign particle testing.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Strength

If a vacuum chuck is used for the EUV mask, then the mask can be held securely, but foreign particles between the chuck and mask cause deformation and pattern distortion

Engineering Contradiction:

Improvemask holding forceVSAvoidpattern accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

Foreign particles are extracted or removed from the interface between the vacuum chuck and the EUV mask before the chucking process. This extraction prevents particles from causing deformation, allowing the vacuum chuck to maintain both strong holding force and high pattern accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method enables efficient particle removal without damaging the reticle or reattaching particles, reducing manufacturing costs and enhancing the operating rate of exposure apparatuses by eliminating the need for pellicle replacement and minimizing air bubble formation.

Implementation Method 1

a gas supply hole and a gas exhaust hole extending through the cleaner support casing between the another major surface and the recess

Methodology Applied

Scientific EffectGas pressure differential: Pressure Gradient

Implementation Method 2

an electrostatic chuck is employed instead

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS9348218B2Mask cleaner and cleaning method

Publication Date: 2016.05.24 KIOXIA CORP

AI summary

According to one embodiment, a mask cleaner includes a cleaner support casing having a major surface with a recess formed therein, another major surface, and a gas supply hole and a gas exhaust hole extending through the cleaner support casing between the another major surface and the recess, a sticky layer support board attached to the cleaner support casing to block an opening of the recess of the cleaner support casing, and a sticky layer attached to a surface of the sticky layer support board remote from the cleaner support casing.