Al-Ca Alloy Pellicle Frame Flatness

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Solution Overview

Problem

Existing pellicle frames for semiconductor and liquid crystal display manufacturing require complex shapes and processing, leading to increased costs and insufficient flatness, which can cause distortion and reduced overlay accuracy due to deformation stress during lithography.

Innovation Solution

A pellicle frame made from an Al-Ca alloy with a monoclinic Al4Ca phase and specific composition, providing a low Young's modulus and mechanical strength, is used to minimize deformation stress and maintain flatness without a complex shape, utilizing anodized films and suitable manufacturing methods like hot rolling or die casting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a complex shape with quadrangular depression is used for the pellicle frame cross-section, then the deformation stress is reduced and flatness is improved, but the manufacturing process becomes complicated and costs increase

Engineering Contradiction:
Improveflatness of pellicle frameVSAvoidcomplexity of manufacturing process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the material parameter by using Al-Ca alloy with specific composition (5.1-6.1% Zn, 2.1-2.9% Mg, 1.2-2.0% Cu, 0.18-0.28% Cr, ≤0.20% Ti or ≤0.20% Ti and ≤0.02% B, balance Al) to achieve the required flatness without complex shaping. The material composition parameters are optimized to provide the necessary mechanical properties and flatness control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite alloy system (Al-Ca with multiple alloying elements) to achieve the desired properties. This composite material approach allows obtaining the required flatness and mechanical strength without complex geometric shaping, thereby simplifying the manufacturing process.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If the cross-sectional area of the pellicle frame is reduced to minimize deformation stress, then the flatness is improved, but the mechanical strength may be compromised

Engineering Contradiction:
Improveflatness of pellicle frameVSAvoidmechanical strength of pellicle frame
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The invention optimizes the material composition parameters of the Al-Ca alloy to achieve the right balance between flatness and mechanical strength. The specific alloying elements and their concentrations are carefully controlled to provide both the required flatness (through low deformation stress) and sufficient mechanical strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The multi-element alloy composition creates a composite material structure that simultaneously provides the necessary mechanical strength and the low deformation stress required for maintaining flatness. The synergistic effect of multiple alloying elements achieves both competing requirements.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional aluminum alloys are used for the pellicle frame, then the manufacturing is simple, but the flatness is insufficient and distortion occurs during mounting

Engineering Contradiction:
Improvesimplicity of manufacturingVSAvoidflatness of pellicle frame
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention modifies the material parameters by using Al-Ca alloy with specific composition rather than conventional aluminum alloys. This material parameter change provides superior flatness control and resistance to distortion during mounting, while still maintaining relatively simple manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs a composite alloy system (Al-Ca with multiple alloying elements) that provides enhanced flatness and dimensional stability compared to conventional aluminum alloys, while the manufacturing process remains relatively simple through standard casting and heat treatment operations.

Inventive Principle:
Principle #40Composite materials

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 Al-Ca alloy pellicle frame effectively inhibits distortion of photomasks during mounting, maintains excellent flatness, and reduces production costs by simplifying the manufacturing process while ensuring mechanical strength and low Young's modulus.

Implementation Method 1

a pellicle frame with an anodized film on a surface of an aluminum alloy

Methodology Applied
Scientific EffectAnodizing: Anodising

Data Source

PatentEP3486723B1Pellicle frame and pellicle
Publication Date: 2022.11.23 NIPPON LIGHT METAL CO LTD
  • EP3486723B1 patent drawingFigure 1~2
  • EP3486723B1 patent drawingFigure 3~4
  • EP3486723B1 patent drawingFigure 5~6

AI summary

The present invention provides a pellicle frame which can effectively inhibit deformation of an exposure master plate (8) caused by affixing the pellicle (1), and which does not have a complex shape, and a pellicle which uses said pellicle frame are provided. The pellicle frame with an anodized film on a surface of an aluminum alloy frame is characterized in that: the aluminum alloy frame comprises an aluminum alloy which contains Ca: 5.0 to 10.0% by weight with the remainder aluminum and unavoidable impurities are contained, and has an area (volume) ratio of an Al4Ca phase, which is a dispersed phase, is greater than or equal to 25%, and a crystal structure of a part of the Al4Ca phase is monoclinic; wherein the anodized film contains Al4Ca particles.