Image Sensor Package Underfill Seal Pattern Design
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Solution Overview
Problem
Image sensor packages with multi-level stacked structures face limitations due to increasing wiring paths and limited wiring space, which affect signal integrity and power integrity, and result in optical losses.
Innovation Solution
An image sensor package is designed using chip-on-wafer technology with a glass substrate, featuring a seal pattern and protection pattern of different materials, where the seal pattern contacts both the package and glass substrates, and the protection pattern has higher adhesiveness, minimizing area and thickness while optimizing signal and power integrity and reducing optical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a multi-level stacked structure is used in the image sensor package, then the integration density is improved, but the wiring path increases and wiring space is limited, deteriorating signal integrity and power integrity
Solution Approach 1:
The patent transitions from planar wiring to three-dimensional vertical wiring through the stacked structure. Signal lines and power lines are routed through vias connecting different substrate layers (first substrate, second substrate, third substrate), enabling vertical signal transmission that reduces lateral wiring path length while maintaining high integration density.
Solution Approach 2:
The package is divided into multiple functional substrates (first substrate for image sensor chip, second substrate for signal processing, third substrate for I/O) with distinct wiring layers. Each substrate has its own optimized wiring configuration, separating signal routing functions across multiple layers to reduce interference and improve signal integrity.
2Area of moving object
If a multi-level stacked structure is used in the image sensor package, then the integration density is improved, but the wiring path increases and wiring space is limited, deteriorating power integrity
Solution Approach 1:
Power delivery is achieved through vertical via connections between substrates rather than extended lateral traces. The stacked architecture allows power to be transmitted vertically from the third substrate through the second substrate to the first substrate, minimizing power path length and reducing IR voltage drops.
Solution Approach 2:
The second substrate acts as an intermediary layer that receives power from the third substrate and distributes it to the first substrate. This intermediate distribution layer allows for localized power management and reduces the burden on any single power delivery path.
3Ease of manufacture
If the seal pattern and protection pattern use the same material, then the manufacturing process is simplified, but the adhesiveness and sealing performance are insufficient
Solution Approach 1:
Different regions of the package structure use different materials optimized for their specific functions. The seal pattern uses a first material (e.g., underfill resin) optimized for sealing and mechanical bonding, while the protection pattern uses a second material (e.g., adhesive resin) optimized for surface adhesion and protection. This local differentiation improves overall package reliability.
Solution Approach 2:
The package structure employs composite material construction with at least two different materials in the sealing and protection layers. This allows combination of materials with complementary properties - one material providing sealing and structural support, another providing adhesion and surface protection - achieving performance that neither material could provide alone.
Data Source
AI summary
An image sensor package comprises: an image sensor chip configured to convert light collected from an outside thereof into an electrical signal; a package substrate disposed under the image sensor chip the package substrate configured to process the electrical signal converted from the image sensor chip; a glass substrate disposed over the image sensor chip while being spaced apart from the image sensor chip; a seal pattern disposed between an upper surface of the package substrate and a lower surface of the glass substrate while surrounding the image sensor chip; and a protection pattern disposed on the package substrate outside the seal pattern, the protection pattern comprising a single-component material, wherein the seal pattern comprises a material different from the material of the protection pattern.