Shadow Mask Alignment Key Using Fresnel Reflection
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Solution Overview
Problem
Misalignment between deposition objects and shadow masks can lead to deposition material being provided to unintended areas during the manufacturing of electronic devices.
Innovation Solution
A shadow mask with a stacked structure of low- and high-refractive index inorganic layers, including an alignment key, which facilitates precise alignment with deposition objects by utilizing Fresnel reflection for easy identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a shadow mask is used for material deposition, then selective deposition to specific areas is achieved, but misalignment with the deposition object causes material to be deposited in unintended areas
Solution Approach 1:
The patent applies preliminary action by pre-forming an alignment key structure on the shadow mask before the deposition process. This alignment key includes a multi-layer inorganic structure with different refractive indices that creates visible Fresnel reflections, allowing the alignment to be performed in advance and verified before actual material deposition begins, thereby preventing misalignment issues.
Solution Approach 2:
The patent utilizes optical property changes by designing an alignment key with alternating high and low refractive index inorganic layers. This structure produces visible Fresnel reflections that create distinct optical contrast, enabling easy visual detection and verification of alignment between the shadow mask and deposition object before the actual deposition process.
2Measurement precision
If alignment verification is performed during deposition, then alignment accuracy can be confirmed, but the deposition object may be damaged
Solution Approach 1:
The patent introduces an intermediary alignment key structure made of inorganic materials with different refractive indices that does not interfere with the deposition object. This alignment key serves as a mediator that enables optical verification of alignment through Fresnel reflections without requiring direct interaction with or exposure of the deposition object to high-energy measurement tools that could cause damage.
Solution Approach 2:
The patent replaces potential mechanical or high-energy measurement methods with optical measurement based on Fresnel reflections from the multi-layer inorganic alignment key. This substitution allows for non-contact, non-destructive alignment verification using light interaction with the refractive index differences in the alignment key layers.
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
Ensures accurate deposition of materials onto intended areas while allowing non-destructive thickness verification, enhancing manufacturing precision and reducing potential damage to deposition objects.
Implementation Method 1
A shadow mask with a stacked structure of low- and high-refractive index inorganic layers, including an alignment key, which facilitates precise alignment with deposition objects by utilizing Fresnel reflection for easy identification.
Data Source
AI summary
A shadow mask includes a lower inorganic layer, a base layer disposed on the lower inorganic layer, a first upper inorganic layer disposed on the base layer, a second upper inorganic layer disposed on the first upper inorganic layer, and an alignment key disposed on the second upper inorganic layer and having a stacked structure of at least four layers in which a low-refractive index inorganic layer and a high-refractive index inorganic layer are alternately stacked each other in a thickness direction of the lower inorganic layer.