Pellicle Frame Segmented Agglutinant Layer for Photomask Distortion

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Solution Overview

Problem

The increasing densification of semiconductor devices and liquid crystal displays is hindered by pellicle-induced distortion of photomasks, which occurs due to stress from conventional pellicle frames, making it difficult to form finer patterns.

Innovation Solution

A pellicle frame design featuring a sealing material layer made of a soft gel substance on the lower end face and an agglutinant layer provided intermittently on multiple sections, reducing the stress transmitted to the photomask and mitigating Pellicle Induced Distortion (PID).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a continuous agglutinant layer is used to bond the pellicle to the photomask, then the bonding strength is improved, but the photomask distortion (PID) increases

Engineering Contradiction:

Improvebonding strengthVSAvoidpattern positional accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The continuous agglutinant layer is divided into multiple discrete agglutinant portions arranged in a matrix pattern. This segmentation reduces the total bonded area, allowing the pellicle stress to be distributed in a way that minimizes photomask distortion while maintaining sufficient bonding strength through the distributed attachment points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the pellicle lower end face are treated differently: some areas have agglutinant portions for bonding, while other areas are left as non-agglutinant regions to act as stress relief zones. This local differentiation allows the bonded regions to provide attachment strength while the unbonded regions prevent stress transmission that causes PID.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If the pellicle is bonded to the photomask to protect against dust, then the dust protection is improved, but the photomask receives stress causing distortion

Engineering Contradiction:

Improvedust protectionVSAvoidpattern positional accuracy

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The bonding interface is segmented into discrete agglutinant portions rather than a continuous layer. This segmentation maintains dust protection by keeping the pellicle bonded to the photomask at multiple points, while simultaneously reducing overall stress transmission by leaving gaps between the bonded regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The non-agglutinant portions act as intermediary stress relief zones between the pellicle and photomask. These regions allow the pellicle to be supported without direct stress transmission to the photomask, thereby protecting against dust while minimizing PID.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If a soft gel sealing material layer is added to reduce stress, then the PID is reduced, but the device structure becomes more complex

Engineering Contradiction:

Improvepattern positional accuracyVSAvoidpellicle frame structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The agglutinant material parameters are modified to create portions with different bonding characteristics. By controlling the distribution, size, and material properties of discrete agglutinant portions, the stress transmission is reduced without requiring additional complex structural elements like soft gel layers.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The pellicle frame lower end face is designed with a thin film structure that incorporates discrete agglutinant portions. This thin film approach provides flexibility to accommodate stress variations while maintaining the simplified structure, avoiding the need for thicker soft gel material layers.

Inventive Principle:

Principle #30Flexible shells and thin films

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 design effectively reduces the stress on photomasks, suppressing PID and enabling the formation of finer patterns, particularly in EUV lithography where distortion issues are more severe, by distributing and reducing the adhesive stress more effectively than conventional continuous agglutinant layers.

Implementation Method 1

a sealing material layer made of a soft gel substance is provided on the lower end face of the pellicle frame

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

an agglutinant layer is provided on at least a plurality of sections of the lower end face of the pellicle frame

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3971646A1Pellicle frame, photomask, light exposure method, and methods for manufacturing semiconductors and liquid crystal displays

Publication Date: 2022.03.23 SHIN ETSU CHEMICAL CO LTD

AI summary

There is provided a pellicle frame (1), wherein a sealing material layer (5) of a gel-like substance and an agglutinant layer (4) are laid on. The sealing material layer (5) is laid on an end face of the pellicle frame (1) endlessly around the pellicle frame (1). The agglutinant layer (4) is provided outside or inside of the sealing material layer (5) with the agglutinant layer (4) being laid on at a plurality of places of the end face of the pellicle frame (1).