Image Sensor Packaging with Metallic Bump Sealing
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Solution Overview
Problem
Conventional image sensor packaging techniques require multiple process steps and specialized equipment, making them inefficient and costly, especially due to sensitivity to dust and particulates during the packaging process.
Innovation Solution
The image sensor is packaged by forming metallic bumps around the perimeter of the active area, allowing a transparent cover to be glued securely, with electrical connections established using wire bonding techniques and encapsulated in epoxy, enabling efficient packaging without the need for specialized equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging techniques (gluing transparent cover directly to image sensor or using LCOS process with crystalline spacers) are used, then the image sensor is protected from dust and particulates, but the packaging process requires multiple process steps and specialized equipment that is not typically used in IC packaging processes
Solution Approach 1:
The patent introduces metallic bumps as an intermediary element between the transparent cover and the image sensor. These bumps serve multiple functions: they provide mechanical support, create sealing to protect against dust and particulates, and enable attachment without requiring specialized LCOS equipment. The metallic bumps are formed using conventional IC packaging techniques, thus resolving the contradiction between protection reliability and process complexity.
2Productivity
If multiple image sensors are packaged together on the same substrate, then production efficiency is improved, but additional steps such as sawing are required to separate them into individually packaged image sensors
Solution Approach 1:
The patent applies segmentation by packaging multiple image sensors together on a single substrate and then separating them through sawing. This approach allows for batch processing, improving productivity, while the metallic bump structure ensures that each sensor maintains its protective sealing after separation. The segmentation principle resolves the contradiction by enabling efficient bulk packaging while maintaining individual sensor protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method simplifies the packaging process, reduces equipment requirements, and effectively protects electrical connections while maintaining the sensitivity of the image sensor, allowing for efficient production and integration with conventional IC packaging technologies.
Implementation Method 1
The transparent cover is then glued to the image sensor at the metallic bumps
Implementation Method 2
The electrical connections are encapsulated within an epoxy for protection
Data Source
AI summary
An image sensor is packaged by attaching the image sensor to a substrate, forming metallic bumps on either the image sensor or a transparent cover, where the metallic bumps are formed in a pattern around the perimeter of the active area of the image sensor. The transparent cover is then glued to the image sensor at the metallic bumps. Electrical connections are formed between the image sensor and the substrate using, for example, conventional wire bonding techniques. The electrical connections are encapsulated within an epoxy for protection. In an embodiment, multiple image sensors are packaged together on the same substrate and separated into individually packaged image sensors by, for example, sawing.