Electrostatic Mask Stage Layout for Deposition Mask Warpage
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Solution Overview
Problem
Warpage of deposition masks during the manufacturing process leads to deteriorated pixel position accuracy and color mixing in high-resolution display devices, such as HMDs and AR glasses, due to loss of parallelism between the backplane substrate and the deposition mask.
Innovation Solution
A mask stage with a lattice support and electrostatic chucks is used to hold the deposition mask, employing electrostatic forces to reduce warpage by supporting the edge and closed cell regions, ensuring precise alignment and reducing color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a deposition mask is used in a deposition process for forming light emitting layers, then light emitting layers of sub-pixels can be formed on a backplane substrate, but warpage of the deposition mask causes deteriorated pixel position accuracy and color mixing between sub-pixels
Solution Approach 1:
The support structure is divided into multiple discrete support regions (first support region, second support region, third support region) that are distributed across the deposition mask. Each support region provides localized support to specific areas (edge region, central region, and intermediate regions), preventing warpage while maintaining the overall flatness and parallelism of the mask during the deposition process.
Solution Approach 2:
Different support regions are strategically positioned to provide tailored support to different areas of the deposition mask. The first support region supports the edge region, the second support region supports the central region, and the third support region supports intermediate regions. This localized support approach addresses the specific warpage tendencies of different mask areas, ensuring uniform pixel position accuracy across the entire substrate.
2Stability of the object's composition
If the deposition mask is supported at multiple regions, then warpage is reduced and parallelism is maintained, but the device complexity increases
Solution Approach 1:
The support structure incorporates a lattice support with a porous or grid-like configuration. This lattice structure provides mechanical support while maintaining transparency to the deposition flux, allowing the deposition material to pass through to the substrate without significant interference. The porous design reduces material usage and simplifies the overall structure compared to solid support blocks, while still effectively preventing mask warpage.
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 solution effectively reduces warpage, maintaining pixel position accuracy and preventing color mixing, enabling high-resolution image display in wearable devices like HMDs and AR glasses without user dizziness.
Implementation Method 1
a first electrostatic chuck which surrounds the lattice support, supports an edge region of the deposition mask, and holds the edge region of the deposition mask using a first electrostatic force
Implementation Method 2
at least one second electrostatic chuck which is disposed on the at least one chuck mount region, supports a portion of the deposition mask, and holds the portion of the deposition mask using a second electrostatic force
Data Source
AI summary
Provided are a mask stage, a deposition apparatus including the mask stage, and an electronic device manufactured by using the deposition apparatus. The mask stage includes a lattice support which supports a deposition mask and comprises a plurality of opening regions and at least one chuck mount region, a first electrostatic chuck which surrounds the lattice support, supports an edge region of the deposition mask, and holds the edge region of the deposition mask using a first electrostatic force, and at least one second electrostatic chuck which is disposed on the at least one chuck mount region, supports a portion of the deposition mask, and holds the portion of the deposition mask using a second electrostatic force.