Image Sensor Package Bonding Dam Optimization
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Solution Overview
Problem
As the resolution of image sensors increases, the area of the pixel region grows while the area of the non-sensing region decreases, posing challenges in maintaining bonding strength and mechanical reliability when reducing the width of the bonding dam for the cover glass.
Innovation Solution
The image sensor package incorporates a bonding dam with a reduced width of 160 μm to 240 μm, spaced 80 μm to 150 μm from the image sensor chip's edge, combined with an encapsulation layer covering the bonding dam, cover glass, and printed circuit board edges, to secure bonding strength and mechanical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the resolution of image sensor increases, then the area of pixel region increases, but the area of non-sensing region decreases
Solution Approach 1:
The bonding dam is positioned specifically in the non-sensing region with optimized dimensions (width: 160-240 μm, height: 50-150 μm, spacing: 80-150 μm from chip edge) to provide localized bonding function without encroaching on the pixel region, allowing high resolution imaging while maintaining bonding capability
2Area of stationary object
If the width of bonding dam is reduced, then the package size is minimized, but the bonding strength and mechanical reliability deteriorate
Solution Approach 1:
The bonding dam dimensions are optimized within specific ranges (width: 160-240 μm, height: 50-150 μm) to achieve the best balance between minimizing package size and maintaining bonding strength. The encapsulation layer is applied to cover the bonding dam, providing additional mechanical support and protection to enhance reliability while keeping the bonding dam width limited
3Area of stationary object
If the width of bonding dam is reduced, then the non-sensing region area decreases, but the risk of glue entering active pixel sensor region increases
Solution Approach 1:
The encapsulation layer serves as an intermediary barrier that covers the bonding dam and prevents glue from entering the active pixel sensor region during the bonding process. This allows the bonding dam to be positioned closer to the pixel region (reducing non-sensing region area) while eliminating the contamination risk
Data Source
AI summary
An image sensor package including an image sensor chip including an active pixel sensor region and a non-sensing region, a plurality of chip pads being in the non-sensing region; a printed circuit board on one side of the image sensor chip, the printed circuit board including a plurality of bonding pads; conductive wires respectively connecting the plurality of chip pads to the plurality of bonding pads; a bonding dam at a periphery of the active pixel sensor region; a cover glass on the bonding dam and facing another side of the image sensor chip; and an encapsulation layer covering a side surface of the bonding dam, a side surface of the cover glass, an edge of a lower surface of the cover glass, the non-sensing region, and an edge of an upper surface of the printed circuit board, wherein the bonding dam is spaced apart from an end of a side surface of the image sensor chip by a distance of 80 μm to 150 μm has a height of 50 μm to 150 μm from the image sensor chip, and has a width of 160 μm to 240 μm.