Back-illuminated Sensor Chip Step-like Peripheral Design
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Solution Overview
Problem
Conventional camera image sensors suffer from non-uniform imaging quality due to lens-related issues, with arc-shaped silicon substrates introducing stress and potential chip deterioration, leading to reduced yield and imaging quality.
Innovation Solution
A back-illuminated sensor chip design featuring a step-like configuration with a peripheral portion protruding outward beyond the central portion, where the peripheral portion has a higher height and ion concentration than the central portion, optimizing light sensitivity and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an arc-shaped silicon substrate is used to solve non-uniform imaging quality, then the imaging quality uniformity between central and peripheral areas is improved, but the chip is subjected to additional stress causing cracking and deterioration of imaging quality
Solution Approach 1:
The pixel area is divided into a central portion and a peripheral portion with different heights, creating a step-like configuration. This segmentation allows each region to have optimized characteristics: the peripheral portion protrudes closer to the lens for better light collection, while the central portion remains at a standard height, avoiding the stress issues of a complete arc-shaped substrate.
Solution Approach 2:
Different regions of the pixel area are given different structural properties. The peripheral portion is designed with a greater height (10-200 μm taller) to increase light sensitivity in areas that naturally receive less light, while the central portion maintains standard height. This local differentiation optimizes imaging quality across the entire sensor surface without introducing global stress.
2Use of energy by moving object
If the peripheral portion is made taller to increase light sensitivity, then the light sensitivity in peripheral areas is improved, but the manufacturing complexity and stress control requirements increase
Solution Approach 1:
The height parameter of the peripheral portion is specifically optimized to be 10-200 μm greater than the central portion. This controlled parameter change increases light sensitivity without excessive complexity. The ion concentration in the peripheral portion is also adjusted to be higher than in the central portion, further optimizing light sensitivity while maintaining manageable manufacturing requirements.
Data Source
AI summary
A back-illuminated sensor chip is disclosed, which includes one or more pixel areas each including a plurality of pixels located in a plane and arranged in a matrix. Each pixel area includes: a central portion consisting of a plurality of first pixels located in vicinity of a center of the pixel area; and a peripheral portion surrounding the central portion and consisting of the other pixels in the pixel area than the first pixels. The plurality of first pixels have a first height in a vertical direction perpendicular to the plane, and the pixels in the peripheral portion have a second height in the vertical direction that is greater than the first height so that the peripheral portion protrudes outward beyond the central portion and is thus located nearer to a light source during imaging than the central portion. As a result, light sensibility of the peripheral portion is increased.