Pellicle Frame Anodic Oxide Film Haze and Glittering Control

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Solution Overview

Problem

The challenge is to prevent the generation of haze and surface glittering defects under irradiation with collected light in pellicle frames, particularly when using an alkaline electrolytic solution for anodic oxide film formation, as existing methods struggle to control crystallized products like Mg2Si, AlCuMg, and Al-Fe-based compounds effectively.

Innovation Solution

A pellicle frame made from an Al-Zn-Mg-based aluminum alloy with specific component compositions and processing steps, including homogenization and anodic oxidation using dicarboxylic or tricarboxylic acid salts, is developed to control the size and distribution of crystallized products, reducing their glittering effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an alkaline electrolytic solution containing organic acid salt is used for anodic oxidation to prevent haze, then haze generation is suppressed, but surface glittering defects increase under collected light irradiation

Engineering Contradiction:
Improvehaze generationVSAvoidsurface glittering defect
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the electrolytic solution by specifying precise concentrations of organic acid salts (tartrate, citrate, or oxalate) ranging from 5-200 g/L, along with controlled amounts of inorganic acid (0-50 g/L) and alkali metal hydroxide (1-100 g/L). This parameter optimization allows the formation of anodic oxide films that suppress haze while minimizing surface glittering defects under collected light irradiation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite electrolytic solution system combining organic acid salts (tartrate, citrate, or oxalate) with inorganic acid and alkali metal hydroxide. This composite approach creates anodic oxide films with optimized structural and chemical properties that simultaneously address both haze prevention and surface glittering reduction, achieving a balance between the two harmful effects.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If inorganic acid remains in the anodic oxide film, then haze is generated under high-energy light, but using organic acid salt alone increases surface glittering defects

Engineering Contradiction:
Improvehaze under high-energy lightVSAvoidsurface glittering defect
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The invention optimizes the concentration parameters of both organic acid salts (5-200 g/L) and inorganic acid (0-50 g/L) in the electrolytic solution. This precise parameter control allows the anodic oxide film to contain sufficient organic acid salt to suppress haze under high-energy light while maintaining low levels of inorganic acid to minimize surface glittering defects.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces organic acid salts (tartrate, citrate, or oxalate) as intermediary substances that mediate between the anodic oxidation process and the final film properties. These organic acid salts act as structure-directing agents during film formation, creating a porous anodic oxide structure that reduces haze generation while the controlled inorganic acid content prevents excessive surface glittering.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively reduces surface glittering defects and haze generation, ensuring accurate visual inspection and improved manufacturing yields in semiconductor device production, even under high-energy light exposure.

Implementation Method 1

the anodic oxide film is obtained through anodic oxidation processing using an alkaline electrolytic solution containing as an electrolyte any one kind or two or more kinds selected from the group consisting of dicarboxylic acid salts and tricarboxylic acid salts

Methodology Applied
Scientific EffectAnodic oxidation: Anodising

Data Source

PatentEP2930563B1Pellicle frame and process for manufacturing same
Publication Date: 2018.01.31 NIPPON LIGHT METAL CO LTD
  • EP2930563B1 patent drawingFigure 1A~1B
  • EP2930563B1 patent drawingFigure 2A~2C

AI summary

Provided is a pellicle frame that can prevent generation of haze and reduces a surface glittering defect under irradiation with collectedlight, and a method of manufacturing the same. Thepellicle frame is obtained by using an aluminum frame material having a structure satisfying predetermined conditions on the circle-equivalent diameters of a Mg2Si crystallized product, an Al2CuMg crystallized product, an Al-Fe-based crystallized product (AlmFe or Al7Cu2Fe), and an Al2CuMg crystallized product and on the area ratios of those crystallized products each having a circle-equivalent diameter of 1 µm or more, and in addition, subjecting the aluminum frame material to anodic oxidation processing using an alkaline electrolytic solution containing as an electrolyte a predetermined organic acid salt. In addition, the method of manufacturing a pellicle frame includes: preparing an aluminum frame material having a structure as described above; and subjecting the aluminum frame material to anodic oxidation processing using an alkaline electrolytic solution containing a predetermined organic acid salt, to form an anodic oxide film.