Drive Backplane Via Structure for Corrosion-Resistant IC Bonding
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Solution Overview
Problem
The existing Micro-LED display products face issues due to the IC occupying display area, leading to stitching gaps, and the metal structure of connecting terminals being exposed, causing oxidation and corrosion, which affects the yield of drive circuits.
Innovation Solution
A drive backplane structure is developed with a flexible substrate, a first passivation layer, a thin film transistor, and an electrical connecting structure, including a signal trace and a connecting terminal. The connecting terminal is designed with a first portion between the flexible substrate and the passivation layer and a second portion within a via hole, ensuring protection from oxidation and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connecting terminal is completely exposed to air environment for IC bonding, then the bonding process can be simplified, but the metal structure becomes susceptible to oxidation and corrosion
Solution Approach 1:
The patent introduces a passivation layer as an intermediary between the connecting terminal and the external environment. This passivation layer selectively covers the metal structure while leaving the bonding pad area exposed, thereby preventing oxidation and corrosion of the connecting terminal during the bonding process without complicating the manufacturing procedure
Solution Approach 2:
The patent applies different protective qualities to different regions of the substrate. The passivation layer is configured to cover specific areas (connecting terminals) while leaving other areas (bonding pads) exposed, creating local quality differences that satisfy both protection and manufacturing simplicity requirements
2Ease of manufacture
If the IC is bonded to the front side of the screen, then the bonding process is straightforward, but the IC occupies display area causing stitching gaps
Solution Approach 1:
The patent inverts the conventional bonding approach by bonding the IC to the back side of the flexible substrate instead of the front side. This inversion allows the connecting terminals to be accessible on the back side for bonding, while the front side remains fully available for display purposes, eliminating stitching gaps in the display area
Solution Approach 2:
The patent moves the bonding operation from the front side (two-dimensional plane) to the back side (third dimension), utilizing the z-axis dimension to resolve the conflict between bonding accessibility and display area utilization. This dimensional transition allows both functions to coexist without interference
Data Source
AI summary
The present application discloses a drive backplane and a preparation method thereof, a display panel, and a display device. The drive backplane includes a flexible substrate provided with a first via hole; a first passivation layer located on a side of the flexible substrate and provided with a second via hole, an orthographic projection of the second via hole being at least partially overlapped with an orthographic projection of the first via hole; a thin film transistor located on a side, facing away from the flexible substrate, of the first passivation layer; and an electrical connecting structure, including a signal trace and a connecting terminal.