BSI Image Sensor Metal Rings Reduce Optical Cross-Talk
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Solution Overview
Problem
Conventional Backside Illumination (BSI) image sensor chip formation processes suffer from optical cross-talk between light received by different image sensors due to the lack of effective separation of color filters and interconnect structures.
Innovation Solution
The formation of clear color-filters and metal rings on the backside of the BSI image sensor chip, where clear color-filters are patterned to overlap image sensors and metal rings are etched to encircle these filters, preventing light from crossing over to adjacent colored filters, thereby reducing optical cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If color filters are formed on the backside of the BSI image sensor chip, then light signal conversion accuracy is improved, but optical cross-talk between adjacent filters increases
Solution Approach 1:
The patent divides the color filter structure into separate, isolated units by forming individual metal rings around each clear color filter. This segmentation physically separates adjacent filters, preventing light from crossing over to neighboring filters and eliminating optical cross-talk while maintaining accurate light signal conversion for each sensor element.
2Ease of manufacture
If conventional BSI image sensor chip formation process is used, then manufacturing simplicity is maintained, but optical cross-talk between different image sensors occurs
Solution Approach 1:
The patent combines multiple functions into the metal ring structure: it serves as both an interconnect element and an optical isolation barrier. By integrating these functions, the design maintains manufacturing simplicity while effectively blocking optical cross-talk, as the same structural feature that connects electrical circuits also prevents light leakage between adjacent pixels.
3Reliability
If clear color-filters are patterned to overlap image sensors, then light signal detection is improved, but light blocking to adjacent filters increases optical cross-talk
Solution Approach 1:
The patent introduces metal rings as intermediary structures between clear color filters. These metal rings act as optical mediators that block light propagation to adjacent filters while allowing the clear filters to maintain their light detection function. The intermediary structure resolves the conflict between effective light detection and prevention of optical cross-talk.
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 solution effectively minimizes optical cross-talk by blocking and reflecting light between clear and colored filters, enhancing the accuracy and efficiency of light signal conversion into electrical signals for each image sensor.
Implementation Method 1
metal rings are etched to encircle these filters, preventing light from crossing over to adjacent colored filters
Implementation Method 2
blocking and reflecting light between clear and colored filters
Data Source
AI summary
A device includes a semiconductor substrate having a front side and a backside. A plurality of image sensors is disposed at the front side of the semiconductor substrate. A plurality of clear color-filters is disposed on the backside of the semiconductor substrate. A plurality of metal rings encircles the plurality of clear color-filters.