Undulated Vapor Deposition Mask Substrate for Pattern Accuracy

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Solution Overview

Problem

Vapor deposition masks face challenges in achieving accurate pattern formation due to vapor deposition material adhering to the wall surfaces of the mask, which reduces the dimensional accuracy and requires thinner metal sheets, complicating the etching process and increasing the difficulty in achieving precise dimensional accuracy.

Innovation Solution

A vapor deposition mask substrate with an undulated shape, where the steepness of the undulations in the center section is less than or equal to 0.3% and the edge sections are less than or equal to 0.6%, allowing for improved flow of liquids and reducing adhesion issues, thereby enhancing the accuracy of pattern formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the thickness of the metal sheet is reduced to reduce the amount of vapor deposition material adhering to the wall surfaces, then the dimensional accuracy of the pattern is improved, but the permissible ranges in the processing conditions are narrowed and the difficulty in achieving the required dimensional accuracy of the openings increases

Engineering Contradiction:

Improvedimensional accuracy of the patternVSAvoidease of etching the metal sheet

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the physical parameter of the metal sheet surface by controlling the undulation shape during the rolling process. By adjusting the rolling conditions to create specific undulation patterns with controlled steepness ratios, the patent modifies the surface morphology to improve etching uniformity while maintaining thin thickness, thus resolving the contradiction between pattern accuracy and manufacturing ease.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the thickness of the metal sheet is reduced to reduce the amount of vapor deposition material adhering to the wall surfaces, then the dimensional accuracy of the pattern is improved, but the volume of metal to be removed during etching is reduced which narrows the permissible ranges in processing conditions

Engineering Contradiction:

Improvedimensional accuracy of the first and second openingsVSAvoidvolume of metal to be removed

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent transforms the metal sheet surface into an undulated structure with controlled steepness ratios during the rolling process. This parameter change in surface morphology compensates for the reduced metal volume by creating a surface structure that ensures uniform etchant distribution and contact time, thereby maintaining opening dimensional accuracy even with thinner sheets.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the metal sheet has an undulated shape from rolling or electrolysis, then the metal sheet can be manufactured, but the duration for which the ridges and valleys are in contact with the etchant differs greatly which aggravates the reduced accuracy

Engineering Contradiction:

Improveease of manufacturing the metal sheetVSAvoiddimensional accuracy of the openings

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality control by specifying different steepness ratio requirements for different regions of the undulated surface. By controlling the steepness ratio to be within a specific range (1:10 to 1:20) across the entire surface, the patent ensures that both ridges and valleys have optimized contact characteristics with the etchant, improving etching uniformity while maintaining the manufacturability of the undulated structure.

Inventive Principle:

Principle #3Local quality

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 undulated shape of the vapor deposition mask substrate improves the uniformity of processing, increases the accuracy of pattern formation, and reduces the need for frequent mask replacements by minimizing liquid stagnation and adhesion issues, leading to more consistent and precise vapor deposition patterns.

Implementation Method 1

improves the flow of liquids and reducing adhesion issues

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

In the process of etching the metal sheet to form holes

Methodology Applied

Scientific EffectEtching:

Implementation Method 3

at least some of the vapor deposition material entering the hole through the second opening adheres to the wall surface defining the hole

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11339465B2Vapor deposition mask substrate, vapor deposition mask substrate manufacturing method, vapor deposition mask manufacturing method, and display device manufacturing method

Publication Date: 2022.05.24 TOPPAN HOLDINGS INC

AI summary

The percentage of a height of each undulation with respect to a length of the undulation is a unit steepness. A steepness is an average value of unit steepnesses of all undulations in a longitudinal direction at each of different positions in a width direction of a metal sheet. The maximum value of steepnesses in a center section in the width direction is less than or equal to 0.3%. The maximum value of steepnesses in a first edge in the width direction and a maximum value of steepnesses in a second edge section in the width direction are less than or equal to 0.6%. The maximum value of steepnesses in at least one of the first edge section and the second edge section in the width direction is less than the maximum value of steepnesses in the center section in the width direction.