CVD Sealing Layer Cycling to Prevent OLED Void Formation
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Solution Overview
Problem
The manufacturing process of OLED display devices faces challenges in maintaining reliability due to issues such as void formation in sealing layers, which can lead to reduced performance and increased manufacturing costs.
Innovation Solution
A manufacturing method involving a CVD device that uses a combination of deposition and anisotropic dry etching processes to form silicon nitride sealing layers, ensuring the layers are free from voids and enhancing sealing performance, while also using a cap layer and partition structure to prevent moisture ingress and maintain optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing layer is formed using conventional deposition processes, then the sealing layer can be created, but voids form within the layer reducing reliability
Solution Approach 1:
The sealing layer formation process is segmented into multiple deposition steps with intermediate etching processes. Instead of forming the complete sealing layer in a single deposition step, the process divides it into sequential layers with cleaning steps in between, ensuring each layer is void-free while maintaining overall sealing integrity.
Solution Approach 2:
Before forming the complete sealing layer, preliminary deposition and etching steps are performed to prepare the surface and prevent void formation. The intermediate etching process removes potential defects and ensures proper adhesion before subsequent deposition layers are added.
2Manufacturing precision
If multiple deposition and etching steps are performed to prevent voids, then sealing layer quality improves, but manufacturing process complexity increases
Solution Approach 1:
The deposition and etching processes are merged into an integrated sequence where each deposition step is immediately followed by an etching step within the same chamber setup. This combination approach maintains high precision while reducing the need for separate equipment and manual interventions.
Solution Approach 2:
The intermediate etching process automatically removes potential defects and prepares the surface for the next deposition layer without requiring external intervention. The process self-corrects potential void formation issues through the built-in etching step that follows each deposition.
3Reliability
If the sealing layer is made thick to prevent moisture ingress, then sealing performance improves, but transmittance and color accuracy deteriorate
Solution Approach 1:
The sealing layer is designed with varying local properties - the intermediate layers have different thicknesses and compositions optimized for their specific functions. The first sealing layer provides moisture barrier function while the second layer maintains optical quality, with each layer having locally optimized characteristics rather than uniform properties throughout.
Solution Approach 2:
The sealing structure uses composite material composition with silicon nitride as the base material, forming a multi-layer composite structure. This composite approach allows different layers to provide different functions - moisture blocking in the first layer and optical quality in the second layer - achieving both sealing performance and optical transparency.
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 prevents reliability reduction by ensuring void-free sealing layers, improving manufacturing yield, and maintaining high transmittance and color accuracy in OLED display devices.
Implementation Method 1
a deposition process of introducing a material gas into the chamber, depositing silicon nitride on the processing substrate
Implementation Method 2
an etching process of introducing a cleaning gas into the chamber through a same route as the material gas, performing anisotropic dry etching for removing part of the silicon nitride deposited on the processing substrate
Data Source
AI summary
According to one embodiment, a manufacturing method of a display device includes forming a sealing layer. The forming the sealing layer includes a deposition process of introducing a material gas into a chamber, depositing silicon nitride on a processing substrate, stopping introduction of the material gas and evacuating a residual gas of inside of the chamber, and an etching process of introducing a cleaning gas into the chamber through a same route as the material gas, performing anisotropic dry etching for removing part of the silicon nitride deposited on the processing substrate, and evacuating a residual gas of the inside of the chamber. A combination of the deposition process and the etching process is performed at least twice.