Ag-In Alloy Sputtering Target for OLED Reflection Electrodes

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Solution Overview

Problem

The existing Ag alloy films used in OLED elements face challenges in achieving low resistance, high reflectance, low surface roughness, high sulfidation resistance, and heat resistance, leading to defects in the transparent conductive film and reduced production yield, as well as issues with abnormal electrical discharge and splashing during sputtering.

Innovation Solution

An Ag-In alloy sputtering target with specific compositions of 0.1 at% to 1.5 at% In, 0.2 at% to 2.0 at% Sb, and reduced amounts of Si, Cr, Fe, and Ni (30 ppm or less) is used to form a reflection electrode film, which reduces surface roughness, sulfidation resistance, and heat resistance, while minimizing abnormal electrical discharge and splashing during sputtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If In is added to Ag to improve hardness and suppress bending, then target strength is improved, but surface roughness increases and production yield decreases

Engineering Contradiction:
Improvetarget strengthVSAvoidsurface roughness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent optimizes the In content parameter within a specific range (0.1-1.5 at%) to achieve the desired balance between target strength and surface roughness. This parameter optimization resolves the contradiction by finding the optimal value that satisfies both requirements simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite Ag-In alloy material with specific composition ratios. By combining Ag and In in controlled proportions, the material achieves both improved mechanical strength from In addition and maintained surface quality through controlled composition, resolving the contradiction between strength enhancement and surface roughness.

Inventive Principle:
Principle #40Composite materials

2Reliability

If In is added to Ag to improve corrosion resistance and heat resistance, then film stability is improved, but surface roughness increases causing defects in upper-layer transparent conductive film

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidsurface roughness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent precisely controls the In content parameter (0.1-1.5 at%) to achieve optimal balance. This parameter optimization ensures that the corrosion resistance and heat resistance improvements from In addition are achieved while keeping surface roughness within acceptable limits for subsequent transparent conductive film formation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If Si, Cr, Fe, and Ni are reduced to 30 ppm or less, then abnormal electrical discharge and splashing are minimized, but manufacturing complexity increases

Engineering Contradiction:
Improvesputtering stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent sets specific parameter thresholds for impurity elements (Si, Cr, Fe, Ni ≤ 30 ppm each) to ensure sputtering stability and minimize abnormal electrical discharge. This parameter specification resolves the contradiction by defining clear manufacturing targets that, while requiring precision, provide predictable and reliable sputtering processes.

Inventive Principle:
Principle #35Parameter changes

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 Ag-In alloy sputtering target enhances the production yield and high-definition quality of OLED panels by reducing abnormal electrical discharge and splashing, maintaining reflectance before and after heat treatment, and improving the overall performance of the reflection electrode film.

Implementation Method 1

a sputtering method is employed, and a silver alloy sputtering target is used

Methodology Applied
Scientific EffectSputtering: Sputtering

Data Source

PatentEP2937444B1Ag-in alloy sputtering target
Publication Date: 2017.08.16 MITSUBISHI MATERIALS CORP

AI summary

The present invention provides an Ag-In alloy sputtering target which can reduce the occurrence of abnormal electrical discharge or splashing in sputtering to form a reflection electrode film formed from Ag-In alloy. The Ag-In alloy sputtering target of the present invention contains 0.1 at% to 1.5 at% of In and the balance including Ag and inevitable impurities. The amount of each of elements Si, Cr, Fe and Ni are equal to or less than 30ppm and the sum of their amounts is equal to or less than 90ppm.