Oxide Support Structures for Color Filter Thickness Uniformity
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Solution Overview
Problem
Conventional CMOS image sensors experience image quality degradation due to non-uniform color filter thickness variations in color filter arrays, leading to undesired color shading issues.
Innovation Solution
Incorporating oxide support structures within the color filter array to maintain uniform thickness through surface tension, ensuring each color filter has a consistent and planar surface, thereby reducing color shading variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional color filter arrays are used without support structures, then the manufacturing process is simpler, but the filter thickness uniformity deteriorates causing color shading variations
Solution Approach 1:
The patent introduces oxide support structures as intermediary elements within the color filter array. These support structures act as mediators that maintain the physical integrity and uniform thickness of the color filters during manufacturing and operation, thereby resolving the contradiction between manufacturing precision and device complexity by adding a structural component that enables better thickness control
Solution Approach 2:
The patent changes the physical and chemical parameters of the color filter array by incorporating oxide support structures with specific material properties. These parameter changes include introducing materials with appropriate thermal expansion coefficients, mechanical strength, and chemical stability to maintain filter thickness uniformity while managing the increased structural complexity
2Ease of manufacture
If color filter thickness varies within the wafer, then manufacturing is easier, but image quality deteriorates due to color shading variations
Solution Approach 1:
The oxide support structures serve as intermediary elements that decouple the manufacturing process from the final thickness uniformity requirement. By providing structural support during fabrication, these intermediaries enable easier manufacturing while ensuring the color filters maintain uniform thickness, thus resolving the contradiction between ease of manufacture and manufacturing precision
Solution Approach 2:
The patent implements beforehand cushioning by incorporating support structures that preemptively compensate for potential thickness variations during the manufacturing process. These support structures are placed in advance to prevent sagging or deformation of the color filters, ensuring uniform thickness is maintained throughout fabrication without requiring extremely precise manufacturing controls
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
The implementation of oxide support structures in the color filter array enhances filter thickness uniformity, resulting in improved image quality by minimizing color shading variations and maintaining consistent image capture across the sensor.
Implementation Method 1
Incorporating oxide support structures within the color filter array to maintain uniform thickness through surface tension
Data Source
AI summary
A color filter array for use on a color image sensor includes an oxide grid having sidewalls arranged to define openings in the oxide grid. Each one of the openings is to be disposed over a corresponding pixel cell of the color image sensor. Oxide support structures are disposed in an interior region of each opening in the oxide grid over a corresponding pixel cell of the color image sensor. The openings in the oxide grid are filled with color filter material of a corresponding color filter. A surface tension between each oxide support structure and the surrounding color filter material of the color filter is adapted to provide uniform thickness for the color filters within the corresponding openings in the oxide grid.