IC Package Barrier Bumps Prevent COP Bonding Short-Circuits
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Solution Overview
Problem
In the COP bonding process for integrated circuit packages, conductive balls can conglomerate between neighboring bumps, leading to short-circuits, particularly on flexible plastic substrates which deform under heat and pressure, causing electrical connectivity issues.
Innovation Solution
The integration of first and second barrier bump areas on the IC package, separated from input and output bump areas, which guide and block conductive balls to prevent congregation and short-circuiting, using a specific arrangement of barrier bumps to manage the flow of conductive balls during the bonding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the COP bonding process is performed with heat and pressure to bond the IC package to the display panel, then electrical connectivity is achieved through conductive balls, but conductive balls congregate between neighboring bumps causing short-circuits
Solution Approach 1:
Barrier bumps are introduced as intermediary elements between input bumps and output bumps. These barrier bumps act as mediators that redirect and control the flow of conductive balls, preventing them from congregating between input and output bumps while still allowing electrical connectivity to be established through the intended bump connections.
Solution Approach 2:
The bonding area is segmented into distinct regions: input bump areas, output bump areas, and barrier bump areas. This segmentation separates the functional bump regions from the potentially harmful congregation zones, creating designated pathways for conductive balls that prevent short-circuits while maintaining electrical connectivity.
2Reliability
If heat and pressure are applied during the COP bonding process to achieve electrical connectivity, then bumps connect to pads through conductive balls, but the flexible plastic substrate deforms under the heat and pressure
Solution Approach 1:
Barrier bumps are positioned in advance to cushion and redirect the flow of conductive balls before they can congregate in harmful positions. This pre-positioned cushioning effect helps manage the deformation forces during the bonding process, protecting the substrate structure while allowing necessary heat and pressure application for electrical connectivity.
3Reliability
If barrier bump areas are added to prevent conductive ball congregation, then short-circuits are prevented, but the device structure becomes more complex
Solution Approach 1:
The barrier bumps serve multiple functions: they act as physical barriers to prevent conductive ball congregation, they guide the flow of conductive balls toward appropriate targets, and they maintain the structural integrity of the bonding interface. This multi-functionality achieves short-circuit prevention without proportionally increasing device complexity.
Data Source
AI summary
An integrated circuit package and a display device using the same are discussed. The bottom surface of the integrated circuit package includes a first barrier bump area in which a plurality of barrier bumps is arranged, configured to be disposed between an input bump area and an output bump area; and a second barrier bump area in which a plurality of barrier bumps is arranged, configured to be disposed between the first barrier bump area and the output bump area. The first barrier bump area is closer to the input bump area than the second barrier bump area, and the second barrier bump area is closer to the output bump area than the first barrier bump area.