Thin Film Encapsulation Barrier for Optical Devices
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Solution Overview
Problem
Existing encapsulation layers in optical devices, such as LCDs and OLEDs, are thick, which hinders device brightness and color definition, and require multiple chambers for fabrication, leading to decreased throughput.
Innovation Solution
A thin film encapsulation layer comprising a first atomic layer deposition (ALD) layer, a chemical vapor deposition (CVD) layer, and a second ALD layer, which reduces the overall thickness of the encapsulation layer to less than 1 μm, enhancing conformality and reducing seamlines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulation layer thickness is increased to protect the illumination source from moisture and contamination, then the protection capability is improved, but the device brightness and color definition deteriorate
Solution Approach 1:
The encapsulation layer is divided into multiple thin sub-layers (first ALD layer, CVD layer, second ALD layer) instead of using a single thick layer. This segmentation allows the total thickness to be reduced while maintaining protection capability through the combined barrier properties of multiple materials with different functionalities.
Solution Approach 2:
The patent uses a composite structure combining different materials (ALD and CVD deposited layers) with distinct properties. The ALD layers provide excellent barrier properties and conformality, while the CVD layer provides additional protection and stress management, creating a synergistic multi-material system that achieves high protection with reduced thickness.
2Reliability
If a thick encapsulation layer is used to ensure adequate protection, then the barrier performance is improved, but the color definition deteriorates
Solution Approach 1:
The encapsulation function is segmented across multiple thin layers, each contributing to the overall barrier performance. This allows the total thickness to be minimized while maintaining adequate protection, thereby preserving color definition in the display.
Solution Approach 2:
Different regions of the encapsulation structure have different material compositions and thicknesses optimized for their specific functions. The ALD layers provide superior conformal coverage and barrier properties in critical areas, while the CVD layer provides bulk protection, creating local optimization throughout the structure.
3Reliability
If traditional encapsulation fabrication methods are used, then adequate protection is achieved, but the number of chambers required increases leading to decreased throughput
Solution Approach 1:
The patent combines multiple deposition processes (ALD and CVD) into an integrated fabrication sequence that can be performed in fewer chambers. The method merges the advantages of both deposition techniques in a streamlined process flow, reducing the total number of chamber transitions required while maintaining comprehensive protection capability.
Solution Approach 2:
The fabrication process is designed to continue deposition operations across different chamber types without interruption or complete evacuation cycles. The encapsulation layers are deposited in a continuous sequence, minimizing idle time and chamber cycling, thereby increasing overall manufacturing throughput.
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 thin encapsulation layer improves color definition and brightness by reducing layer-to-layer reflection and increasing the ability to protect the illumination source from contaminants, while also increasing throughput by allowing for more conformal deposition and reduced seamlines.
Implementation Method 1
A first atomic layer deposition (ALD) layer is disposed over the capping layer. A second ALD layer is disposed over the CVD layer.
Implementation Method 2
A chemical vapor deposition (CVD) layer is disposed over the first ALD layer.
Data Source
AI summary
Embodiments described herein relate to an optical device and methods of forming an optical device. The optical device includes a substrate, an illumination source, a capping layer, an encapsulation layer, and a passivation layer. The encapsulation layer includes a first atomic layer deposition (ALD) layer, a chemical vapor deposition (CVD) layer, and a second ALD layer. The method includes disposing a capping layer over an illumination layer, the illumination layer disposed over a substrate in a processing chamber; disposing a first atomic layer deposition (ALD) layer over the capping layer; disposing a chemical vapor deposition (CVD) layer over the first ALD layer; disposing a second ALD layer over the CVD layer; and disposing a passivation layer over the second ALD layer.