Dual Dam Layer Image Sensor Structure for Optical Defect Reduction
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Solution Overview
Problem
Image sensors suffer from optical defects due to reflection issues, which compromise product reliability and performance.
Innovation Solution
The design incorporates a chip covered by a cover with a first dam layer and a second dam layer, where the first dam layer is wider and extended to the sensing area, providing light shielding and anti-reflection effects by strategically positioning the second dam layer between the first dam layer and the chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single dam layer is used between the chip and cover, then the structure is simple, but optical defects due to reflection cannot be effectively alleviated
Solution Approach 1:
The single dam layer is segmented into two distinct dam layers with different widths and positions. The first dam layer has a greater width and is extended to the sensing area, while the second dam layer is narrower and positioned between the first dam layer and the chip. This segmentation allows each layer to perform specific optical functions, effectively alleviating optical defects through combined light shielding and anti-reflection effects.
Solution Approach 2:
Different regions of the dam layer structure are assigned different qualities and functions. The first dam layer with greater width provides primary light shielding, while the second narrower dam layer provides secondary shielding and anti-reflection. The asymmetric width design creates local quality variations that optimize optical performance at different positions around the sensing area.
2Reliability
If the dam layer width is increased to improve light shielding, then optical defect alleviation is enhanced, but the device structure becomes more complex
Solution Approach 1:
The light shielding function is segmented across two dam layers with different widths. The first dam layer has a greater width for primary shielding, while the second dam layer has a narrower width for secondary shielding. This segmentation achieves comprehensive light shielding without requiring a single excessively wide dam layer, thereby balancing optical performance with structural complexity.
Solution Approach 2:
The two dam layers are designed with asymmetric widths where the first dam layer is wider than the second dam layer. This asymmetric configuration optimizes the light shielding effect by providing different levels of protection at different radial distances from the sensing area, achieving superior optical performance with a more efficient structure.
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 structural design effectively alleviates optical defects, enhancing the reliability and performance of image sensors by achieving light shielding and anti-reflection, thereby reducing the occurrence of optical defects.
Implementation Method 1
via the structural design of the dam layers, the width of the first dam layer is greater than the width of the second dam layer, and the first dam layer is extended to the sensing area by a distance. In this way, the effect of light shielding/anti-reflection may be achieved
Implementation Method 2
via the structural design of the dam layers, the width of the first dam layer is greater than the width of the second dam layer, and the first dam layer is extended to the sensing area by a distance. In this way, the effect of light shielding/anti-reflection may be achieved
Data Source
AI summary
An image sensor includes a chip, a cover, a first dam layer, and a second dam layer. The chip has a sensing area. The cover covers the chip. The first dam layer and the second dam layer are located between the chip and the cover and surround the sensing area. The second dam layer is located between the first dam layer and the chip, and a width of the first dam layer is greater than a width of the second dam layer, and the first dam layer is extended to the sensing area by a distance. A manufacturing method of an image sensor is also provided.