Deposition Mask Stress Layout for High-Resolution Warpage Control
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Solution Overview
Problem
The production of high-resolution deposition masks for high-resolution displays, such as those used in wearable devices like HMD devices or AR glasses, often results in warpage due to residual stress and thermal expansion differences between the substrate and the membrane, which causes warpage, which affects the production of high-resolution displays.
Innovation Solution
A deposition mask with a mask frame and membrane structure that includes cell regions with residual tensile stress and a grid region with residual compressive stress, along with intermediate regions, all made of inorganic materials, to mitigate warpage by balancing stress levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high-resolution deposition mask is manufactured by forming a membrane with pixel openings on a substrate and partially etching the substrate, then the manufacturing precision for high-resolution displays is improved, but warpage occurs due to residual stress and thermal expansion differences
Solution Approach 1:
The patent applies local quality by creating different stress states in different regions of the membrane. The first region (cell regions above pixel openings) has residual tensile stress while the second region (grid region above non-pixel areas) has residual compressive stress. This localized differentiation of stress properties allows the membrane to compensate for warpage while maintaining high-resolution manufacturing precision.
Solution Approach 2:
The patent changes the stress parameter of the membrane by controlling the formation process to create regions with different residual stresses. The first region is designed to have residual tensile stress (positive value) while the second region has residual compressive stress (negative value). This parameter change enables the membrane to counteract warpage effects and maintain dimensional stability during high-resolution display manufacturing.
2Stability of the object's composition
If the membrane is made with different stress states in different regions, then warpage is reduced, but the device complexity increases
Solution Approach 1:
The patent segments the membrane into distinct functional regions: a first region (cell regions) with residual tensile stress and a second region (grid region) with residual compressive stress. These segmented regions are formed through controlled patterning and deposition processes, allowing independent optimization of stress states in each zone to counteract warpage while maintaining manageable manufacturing complexity.
Solution Approach 2:
The patent employs a composite structure where the membrane combines regions with different stress characteristics. The first region with tensile stress and the second region with compressive stress create a composite stress distribution that balances warpage tendencies. This composite approach allows the membrane to exhibit different mechanical properties in different areas, achieving warpage reduction without requiring entirely new material classes.
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 both cell and global warpage, ensuring the production of high-resolution displays without the distortions caused by residual stress.
Implementation Method 1
The cell regions have a residual tensile stress, and the grid region has a residual compressive stress
Data Source
AI summary
Provided are a deposition mask and a method of manufacturing the deposition mask. The deposition mask includes a mask frame having a plurality of cell openings and including a rib region defining the cell openings, and a membrane including a plurality of cell regions respectively disposed above the cell openings and each having a plurality of pixel openings and a grid region disposed on the rib region. The cell regions have a residual tensile stress, and the grid region has a residual compressive stress.