Image Sensor Package with Grating Film for Adhesive Cure Inspection
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Solution Overview
Problem
In CMOS image sensing chip packaging, the use of thermosetting polymer adhesives for sealing the image sensing region is limited by the inability to optically inspect the curing process, leading to potential defects and reduced yield due to the placement of the adhesive below a black mask, which prevents optical inspection.
Innovation Solution
A chip packaging structure incorporating a grating film that allows light to pass through specific angles, enabling the use of light curing polymer adhesives and real-time optical inspection to monitor curing completion and surface defects between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a black mask is provided on the peripheral region of the cover glass to prevent flare effect, then the image quality is improved, but the polymer adhesive location is below the black mask which prevents optical inspection of the curing process
Solution Approach 1:
The cover glass is divided into two functional regions: a peripheral region with a black mask for preventing flare effect and improving image quality, and a central region without the black mask that allows optical inspection of the polymer adhesive curing process. This segmentation enables both image quality improvement and curing monitoring to coexist.
2Reliability
If thermosetting polymer adhesive is used to attach the cover glass to the dam, then the sealing capability is improved, but the curing process cannot be monitored in real-time leading to potential defects
Solution Approach 1:
A transparent window or opening is introduced as an intermediary element in the cover glass structure, allowing light to pass through to the polymer adhesive layer below. This enables real-time optical monitoring of the curing process while maintaining the sealing capability of the thermosetting adhesive, and allows defect detection during manufacturing.
3Strength
If the polymer adhesive is placed below the black mask region, then the structural integrity is improved, but real-time monitoring of curing completion and surface defects becomes impossible
Solution Approach 1:
The cover glass is designed with non-uniform optical properties: the peripheral region has a black mask for structural support and flare prevention, while the central region has a transparent window that provides localized optical access for monitoring the polymer adhesive curing process, enabling precise measurement of curing completion and surface defects.
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 approach reduces failure modes caused by poor gluing and enhances the yield rate by allowing real-time monitoring of the curing process and surface defects, facilitating the use of light curing polymer adhesives instead of thermosetting ones.
Implementation Method 1
The grating film is disposed on the peripheral region of the second substrate, and the grating film includes a plurality of grating units. Because the light is allowed to pass through the grating film within a viewing angle of the grating film
Data Source
AI summary
A chip packaging structure is provided. The chip packaging structure includes a first substrate, an image sensing chip, a supporting member, a second substrate, a grating film, and an encapsulant. The image sensing chip is disposed on an upper surface of the first substrate and has an image sensing region. The supporting member is disposed on an upper surface of the image sensing chip and surrounds the image sensing region. The second substrate is disposed on an upper surface of the supporting member. The grating film is disposed on a peripheral region of the second substrate and includes a plurality of grating units. The encapsulant is attached to the upper surface of the first substrate, a side surface of the supporting member, and a side surface of the second substrate.