Deposition Mask Metal Plate for Uniform Fine Through-Hole Etching

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Solution Overview

Problem

The challenge lies in creating a deposition mask with uniform and fine through-holes for manufacturing high-definition and ultra-high-definition organic light-emitting diode (OLED) panels, as existing masks face issues with non-uniform deposition and connectivity between adjacent holes, leading to inefficiencies in pattern formation and process efficiency.

Innovation Solution

A metal plate deposition mask is designed with a base metal plate and surface layers having different elemental compositions and etch rates, featuring a Ni-Cr-Fe alloy structure, where the surface layers include Cr, Ni, and Fe with a controlled thickness and composition to slow down etching, ensuring uniform through-hole formation and improved pattern deposition efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a fine metal mask with fine sized through-holes is used to form UHD patterns, then the definition and resolution of the display device is improved, but it becomes difficult to uniformly form the through-holes and adjacent through-holes may connect to each other causing deposition failure

Engineering Contradiction:
Improvethrough-hole uniformityVSAvoiddeposition success rate
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the etching process parameters including using a multi-stage etching approach with different etchants (first etchant for initial through-hole formation, second etchant for refinement), controlling etching time and temperature, and adjusting the composition of the metal plate (Fe-Ni-Cr alloy with specific ratios) to achieve uniform through-hole formation without connectivity issues

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by employing a multi-layer metal plate structure consisting of Fe-Ni-Cr alloy with specific compositional ratios (Fe: 60-70 wt%, Ni: 20-30 wt%, Cr: 5-15 wt%) that provides different etching rates for controlled through-hole formation, preventing adjacent hole connectivity while maintaining uniformity

Inventive Principle:
Principle #40Composite materials

2Productivity

If the etching rate is increased to improve process efficiency, then the manufacturing speed is improved, but the through-holes become non-uniform and deposition efficiency deteriorates

Engineering Contradiction:
Improveetching speedVSAvoidthrough-hole uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the etching process into multiple stages: first etching stage using a first etchant to form initial through-holes, and second etching stage using a second etchant to refine and uniform the through-holes. This segmented approach allows high productivity in the first stage while achieving uniformity in the second stage

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by performing a first etching step to create through-holes before performing a second etching step to refine them. The first etching action prepares the structure for the second action, allowing efficient material removal followed by precision refinement to achieve uniform through-holes

Inventive Principle:
Principle #10Preliminary action

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 solution results in enhanced deposition uniformity and efficiency, allowing for the production of high-definition OLED panels with improved manufacturing yield and process efficiency by controlling the etch rate and preventing photoresist layer de-filming during the etching process.

Implementation Method 1

an etch rate of the base metal plate is greater than those of the first surface layer and the second surface layer

Methodology Applied
Scientific EffectEtching rate difference:

Implementation Method 2

patterns of red (R), green (G), and blue (B) forming a pixel may be formed by depositing the organic material after the fine metal mask is aligned on the substrate

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentEP3514844B1Metal plate for deposition mask, and deposition mask and manufacturing method therefor
Publication Date: 2023.10.04 LG INNOTEK CO LTD
  • EP3514844B1 patent drawingFigure 1~2
  • EP3514844B1 patent drawingFigure 3~4
  • EP3514844B1 patent drawingFigure 5~7

AI summary

A metal plate to be used in the manufacture of a deposition mask comprises: a base metal plate; and a surface layer disposed on the base metal plate, wherein the surface layer includes elements different from those of the base metal plate, or has a composition ratio different from that of the base metal plate, and an etching rate of the base metal plate is greater than the etching rate of the surface layer. An embodiment includes a manufacturing method for a deposition mask having an etching factor greater than or equal to 2.5. The deposition mask of the embodiment includes a deposition pattern region and a non-deposition region, the deposition pattern region includes a plurality of through-holes, the deposition pattern region is divided into an effective region, a peripheral region, and a non-effective region, and through-holes can be formed in the effective region and the peripheral region.