Wafer-Level Image Sensor Package With On-Wafer Light Shields
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Solution Overview
Problem
The existing image sensor packaging methods result in high costs and larger package sizes due to the utilization of discrete optical and protection components, which is unfavorable for applications like mobile and medical use.
Innovation Solution
The method involves forming on-wafer protection and optical components at the wafer level before separating the substrates into discrete dies, replacing individual package components with corresponding on-wafer components, and integrating light shields along the sidewalls of image sensor chips, thereby simplifying the manufacturing process and reducing package size and height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete optical and protection components are used in image sensor packaging, then the image sensor can be protected and functional, but the package size and height increase
Solution Approach 1:
The patent combines discrete optical components (cover glass, light shields, protection layers) into integrated on-wafer structures formed directly on the image sensor chip. The on-wafer shield structure integrates light blocking functionality with the chip substrate, while the on-wafer lens array integrates optical focusing functionality directly onto the wafer surface, eliminating the need for separate discrete components and reducing overall package height.
Solution Approach 2:
The patent transitions from three-dimensional stacked discrete components to two-dimensional planar on-wafer structures. By forming protection layers, light shields, and lenses directly on the wafer surface in the same plane rather than stacking them vertically, the package height is significantly reduced while maintaining all necessary protective and optical functions.
2Reliability
If discrete optical and protection components are used in image sensor packaging, then the image sensor can be protected and functional, but the manufacturing cost increases
Solution Approach 1:
The patent performs preliminary formation of protection layers, light shields, and optical lenses directly on the wafer before dicing into individual chips. This preliminary action allows all protective and optical components to be manufactured in bulk on the wafer using single-step deposition and patterning processes, rather than requiring separate assembly steps for each discrete component after dicing, significantly reducing manufacturing complexity and cost.
Solution Approach 2:
The patent merges multiple discrete components (cover glass, light shields, protection layers, lenses) into unified on-wafer structures that are formed as single integrated units during wafer fabrication. This consolidation eliminates the need to source, handle, and assemble multiple separate components for each chip, reducing both material costs and manufacturing overhead.
3Object-affected harmful factors
If discrete light shields are used around image sensor chips, then light blocking is achieved, but the assembly process becomes complex
Solution Approach 1:
The patent forms light blocking structures as integral parts of the wafer substrate before dicing, using preliminary deposition and patterning steps. This preliminary formation of on-wafer shield structures eliminates the need for separate light shield components that would require precise alignment and attachment during assembly, significantly simplifying the manufacturing process.
Solution Approach 2:
The patent combines the light shield function with the wafer substrate itself, creating on-wafer shield structures that are physically integrated with the chip. This merging of the light blocking function into the substrate eliminates the need for separate discrete light shield components and their associated assembly steps, reducing device complexity.
Data Source
AI summary
A method for forming an image sensor package is provided. An image sensor chip is formed over a package substrate. A protection layer is formed overlying the image sensor chip. The protection layer has a planar top surface and a bottom surface lining and contacting structures under the protection layer. An opening is formed into the protection layer and spaced around a periphery of the image sensor chip. A light shielding material is filled in the opening to form an on-wafer shield structure having a sidewall directly contact the protection layer.