Image Sensor Corner Filter Layout to Prevent Stain Defects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image sensors face a stain defect during the process of forming a color filter structure, particularly in the corner regions between the light receiving and light shielding areas, which affects their reliability.
Innovation Solution
The image sensor design incorporates a substrate with distinct regions, including a color filter structure and a dummy structure, featuring micro-lenses and dummy lenses of varying sizes and slopes, along with a grid pattern and passivation layers, to mitigate the stain defect by optimizing the corner geometry and light condensation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional color filter structure is formed in corner regions, then the light receiving area is maximized, but stain defects occur during the forming process
Solution Approach 1:
The patent applies preliminary action by forming dummy structures (dummy color filters and dummy micro-lenses) in advance at the corner regions before forming the actual color filter structure. These dummy structures pre-occupy the corner spaces and prevent stain defects from occurring during the subsequent color filter formation process, while still allowing the light receiving area to be maximized.
2Reliability
If dummy structures are added to prevent stain defects, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the dummy structures with the existing color filter structure by using the same materials and formation processes. The dummy color filters are formed using the same color filter material, and the dummy micro-lenses are formed using the same lens material and molding process as the actual micro-lenses, thereby preventing stain defects without significantly increasing device complexity.
3Reliability
If corner regions are left empty to avoid stain defects, then reliability is improved, but light receiving area is reduced
Solution Approach 1:
The patent applies local quality by making the dummy structures have different properties from the actual color filter structure. The dummy color filters are positioned only in corner regions and have different dimensions (e.g., smaller area or different shape) compared to the actual color filters, allowing stain prevention in corners while maintaining full light receiving capability in the main sensor area.
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 design enhances the reliability of the image sensor by reducing the occurrence of stains and improving light condensation, thereby enhancing the overall performance and quality of the image sensor.
Implementation Method 1
the color filter structure includes a plurality of first color filters and a plurality of micro-lenses on the plurality of first color filters
Implementation Method 2
semiconductor elements that convert optical information into an electrical signal
Data Source
AI summary
An image sensor includes a substrate including a first region and a second region disposed in a periphery of the first region. The first region includes a plurality of unit pixels and a color filter structure, and the second region includes a dummy structure including a second color filter and a plurality of dummy lenses on the second color filter. The color filter structure includes a first extension portion extending in a first direction and a second extension portion extending in a second direction, and the dummy structure includes a third extension portion extending in the first direction and a fourth extension portion extending in the second direction. A first micro-lens, a second micro-lens, and a third micro-lens are in a first corner portion, and a first dummy lens, a second dummy lens, and a third dummy lens are in the second corner portion.