Image Sensor Package With Backside Via Hole And Conductive Layer
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Solution Overview
Problem
Conventional image sensor packages have large dimensions and are prone to damage during fabrication due to the location of the conductive layer, leading to device failure and increased costs.
Innovation Solution
The image sensor package features a substrate with a via hole and a conductive layer on its backside, where a solder ball electrically connects to the metal layer through the via hole, reducing overall thickness and eliminating the need for extra steps like bonding to a carrying plate, thus simplifying fabrication and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the substrate and carrying plate are made with certain thicknesses to ensure structural integrity, then the mechanical strength is improved, but the overall dimensions of the image sensor package increase
Solution Approach 1:
The invention extracts and eliminates the carrying plate from the package structure. The substrate is thinned to expose the insulator, and the conductive layer is formed directly on the backside of the thinned substrate, extending through via holes to connect bonding pads. This removes the need for a separate carrying plate while maintaining electrical connectivity, thereby reducing overall package thickness and dimensions while preserving mechanical strength through the optimized substrate structure.
2Reliability
If the conductive layer is formed on the exterior area (sidewalls) of the substrate and carrying plate to enable electrical connection, then the electrical connectivity is improved, but the risk of damage during fabrication increases
Solution Approach 1:
The invention transitions the conductive layer from a three-dimensional exterior formation on sidewalls to a primarily two-dimensional planar structure on the backside of the thinned substrate. The conductive layer is formed on the backside and extends through via holes vertically to connect to bonding pads on the front surface. This dimensional change relocates the conductive layer away from vulnerable exterior sidewall positions to more protected planar and internal via hole positions, reducing exposure to mechanical damage during fabrication processes while maintaining effective electrical connectivity between bonding pads.
3Ease of manufacture
If conventional fabrication processes with multiple steps including bonding to carrying plate are used, then the manufacturing completeness is ensured, but the fabrication complexity and cost increase
Solution Approach 1:
The invention merges the functions of the substrate and carrying plate into a single integrated substrate structure. The substrate is thinned and the conductive layer is formed directly on its backside, combining what were previously separate components (substrate and carrying plate) into one unified structure. This integration eliminates the need for separate bonding processes and reduces the number of fabrication steps, thereby simplifying the manufacturing process and reducing costs while ensuring manufacturing completeness through the integrated design.
Data Source
AI summary
An image sensor package and a method for fabricating thereof are provided. A substrate having an insulator filled cavity is provided with an image sensor device electrical connected to a metal layer, thereon. A covering plate is then disposed on the substrate. The substrate is subsequently thinned to expose the insulator. Removing a portion of the insulator, a hole is formed and a conductive layer is filled therein to form a via hole. Next, a solder ball is located over a backside of the substrate which is electrically connected to the metal layer through the via hole. The image sensor package is thinned, thus, the dimensions thereof are reduced.