Chip on Film Package Zigzag Pads Protection Layer
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Solution Overview
Problem
As display devices increase in size and resolution, the close proximity of pad electrodes reduces the process margin, making alignment errors more likely to result in contact failures between chip on film packages and display devices, due to the limited space and decreased distance between pads.
Innovation Solution
A chip on film package design featuring a protection layer with protrusions that cover the output pad wiring between adjacent pads, preventing contact failures by maintaining a distance even with alignment errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of pad electrodes is increased to support larger display size and higher resolution, then the display capability is improved, but the distance between adjacent pad electrodes decreases and process margin is reduced
Solution Approach 1:
The pad electrodes are arranged in a zigzag configuration instead of a straight linear arrangement. This dimensional change in the layout pattern allows more pad electrodes to be accommodated within the same space while maintaining adequate spacing between adjacent pads, thus supporting higher display capability without sacrificing process margin
2Area of stationary object
If the distance between adjacent pad electrodes is decreased to accommodate more pads in limited space, then the device integration is improved, but alignment errors cause contact failures
Solution Approach 1:
A protection layer is formed in advance over the pad electrodes before the bonding process. This preliminary protective measure ensures that even if alignment errors occur during bonding, the pad electrodes are protected from contact failures, thereby maintaining bonding reliability while allowing closer pad spacing
Solution Approach 2:
The protection layer acts as a cushioning layer that compensates for potential alignment errors. By providing this protective buffer beforehand, the system can tolerate closer pad spacing without compromising bonding reliability, as the protection layer prevents direct contact failures during the bonding process
Data Source
AI summary
A chip on film package includes: a base substrate having an output pad region; a plurality of output pads disposed in the output pad region of the base substrate, wherein the output pads are arranged in a zigzag configuration on the base substrate; a plurality of output pad wirings connected to the output pads, respectively; and a protection layer disposed on the output pad wirings. The protection layer is disposed on the output pad wirings disposed between two adjacent output pads, arranged in a first direction.