Micro LED Display Panel Corner Retaining Wall for Pad Etching
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Solution Overview
Problem
In micro LED display panels, especially for frameless panels, the uneven leveling of photoresist at the corner of the panel leads to poor etching of pads, resulting in decreased yield due to inconsistent photoresist thickness.
Innovation Solution
The implementation of a retaining wall structure at the corner of the array substrate, positioned between the pad groups and the edges of the corner, helps to improve the uniformity of the photoresist. This retaining wall structure is formed by patterning the same film layer as the pad groups, ensuring it is electrically connected to the pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photoresist is applied to the corner of the panel without retaining wall structure, then the manufacturing process is simple, but the photoresist thickness is uneven at the corner
Solution Approach 1:
The retaining wall structure is formed in advance during the same patterning process as the pad groups, before photoresist application. This preliminary structural preparation ensures that when photoresist is subsequently applied, the corner areas have proper thickness control due to the retaining walls preventing photoresist flow to the edges, thus achieving uniform thickness without complicating the overall manufacturing process
Solution Approach 2:
The retaining wall structure is specifically positioned at the corner regions where photoresist thickness uniformity is problematic. By locally modifying the corner areas with retaining walls while leaving other regions unchanged, the solution addresses the specific photoresist thickness issue at corners without affecting the simplicity of the overall manufacturing process for the rest of the panel
2Ease of manufacture
If photoresist thickness at corner is insufficient, then the manufacturing process is simple, but the etching of pads at corner is poor
Solution Approach 1:
The retaining wall structure is created in advance during the patterning step, forming physical barriers at the corners before photoresist application. These pre-formed walls ensure that when photoresist is applied later, sufficient thickness is maintained at the corners by preventing flow to the panel edges, thereby ensuring proper pad etching quality without complicating the photoresist application process
Solution Approach 2:
The retaining wall structure preemptively counteracts the tendency of photoresist to flow away from corner areas during application. By establishing these physical barriers in advance, the solution prevents the harmful effect of insufficient photoresist thickness at corners, ensuring adequate thickness for proper pad etching while maintaining simple photoresist application procedures
Data Source
AI summary
A display panel includes an array substrate and light emitting elements. The array substrate includes a substrate, pad groups, and a retaining wall structure. The substrate has a surface. The surface has a corner, and the corner has two edges connected to each other. The pad groups are disposed on the surface and include a first pad groups located at the corner. The retaining wall structure is disposed on the surface and is located at the corner, and is located between the first pad groups and the two edges of the corner. The retaining wall structure and at least one film layer of the pad groups are formed by patterning the same film layer. The light emitting elements are disposed on the pad groups, respectively.