Sputtering Mask for Display Electrode Cluster Control
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Solution Overview
Problem
In the manufacturing of display devices, particularly light-emitting elements, large clusters of conductive oxide sputtered during the formation of electrodes can lead to defects such as dark spots due to incomplete coverage by protection films, causing light emission issues and reducing manufacturing yield.
Innovation Solution
A manufacturing method involving a mask with periodically arranged through holes is used during the sputtering process to prevent large clusters from depositing on the substrate, ensuring complete coverage and preventing defects by trapping clusters on the mask, thereby improving yield and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection film thickness is increased to cover large clusters, then coverage is improved, but light absorption increases and light emission efficiency decreases
Solution Approach 1:
The mask is placed in advance during the sputtering process to intercept and trap large clusters before they reach the substrate. This preliminary action prevents cluster deposition on the substrate, eliminating the need for thick protection films and maintaining high light emission efficiency while ensuring complete coverage.
2Ease of manufacture
If sputtering is performed without a mask, then manufacturing process is simpler, but large clusters deposit on substrate causing dark spots and reducing yield
Solution Approach 1:
A mask with through holes is introduced as an intermediary component between the sputtering target and the substrate. The mask intercepts large clusters during deposition, allowing them to be trapped on the mask surface while permitting normal thin film deposition through the holes. This simple addition significantly reduces dark spots and improves manufacturing yield without complicating the overall process.
3Device complexity
If no mask is used during sputtering, then device structure is simpler, but cluster deposition causes display defects
Solution Approach 1:
The mask converts the harmful effect of cluster generation during sputtering into a beneficial filtering mechanism. Large clusters that would otherwise cause dark spots and display defects are intercepted and trapped on the mask surface, while normal thin film deposition continues uninterrupted through the through holes. This transforms a potentially harmful byproduct into a controlled filtering process.
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 method effectively suppresses display defects, enhances the manufacturing yield of display devices by preventing cluster deposition and maintaining efficient light emission without increasing protection film thickness, which would otherwise absorb light.
Implementation Method 1
forming a second electrode over the organic layer by sputtering a target including a conductive oxide with a light-transmitting property
Data Source
AI summary
A manufacturing method of a display device is provided. The manufacturing method includes: forming a first electrode over a substrate; forming an organic layer over the first electrode; and forming a second electrode over the organic layer by sputtering a target including a conductive oxide with a light-transmitting property. A mask is arranged between the organic layer and the target when the second electrode is formed. The mask has periodically arranged through holes with a maximum width equal to or larger than 0.1 μm and equal to or smaller than 3 μm.