Mask Bar Thickness Layout to Prevent Deposition Lifting
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Solution Overview
Problem
The blocking portions of masks used in display device manufacturing can lift, causing thin films to be stacked on unintended positions during the deposition process, leading to reduced accuracy.
Innovation Solution
A mask assembly design featuring first and second mask bars with specific thickness variations and dummy grooves to maintain consistent contact with the substrate, reducing the likelihood of lifting and ensuring precise deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mask bar has uniform thickness, then the manufacturing process is simple, but the mask bar may lift during deposition causing inaccurate thin film stacking
Solution Approach 1:
The mask bar is designed with non-uniform thickness, featuring a first portion with greater thickness and a second portion with lesser thickness. This local variation in physical properties prevents lifting at critical regions while maintaining structural integrity, directly resolving the contradiction between deposition accuracy and structural simplicity.
Solution Approach 2:
The mask bar is segmented into distinct portions with different thicknesses - a first portion along the edge and a second portion in the interior. This segmentation allows each region to serve different functions: the thicker edge portion prevents lifting and maintains contact, while the thinner interior portion reduces overall complexity and material usage.
2Manufacturing precision
If the mask bar thickness is increased to prevent lifting, then deposition accuracy improves, but the mask assembly complexity increases
Solution Approach 1:
Instead of uniformly increasing mask bar thickness throughout, the invention applies increased thickness locally only at the first portion along the edge where lifting prevention is critical. This targeted approach maintains deposition accuracy while avoiding unnecessary complexity from uniform thickening.
Solution Approach 2:
The solution moves from a one-dimensional uniform thickness parameter to a two-dimensional thickness distribution, varying thickness across different spatial locations of the mask bar. This dimensional approach allows precise control of contact pressure and lifting prevention without requiring uniform increases everywhere.
3Manufacturing precision
If dummy grooves are added to the mask bar, then lifting is prevented and deposition accuracy is maintained, but the manufacturing complexity increases
Solution Approach 1:
Dummy grooves are introduced as localized features at specific positions on the mask bar surface. These grooves create controlled stress distribution and prevent lifting at critical regions without requiring complex overall structural changes, thus maintaining deposition precision while limiting manufacturing complexity to localized modifications.
Data Source
AI summary
A mask assembly and a deposition device including the same are disclosed. A mask assembly includes: a mask frame, a first mask bar connected to the mask frame and extending in a first direction, and a second mask bar connected to the mask frame and extending in a second direction. The first mask bar overlaps the second mask bar in an overlapping region, the second mask bar includes a non-overlapping region not overlapping the first mask bar, the second mask bar includes a first portion having a first thickness and a second portion having a second thickness that is less than the first thickness in the non-overlapping region, and the first portion is located along an edge of the second mask bar.