Solid-State Image Sensor Spectral Correction Buffer Design
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Solution Overview
Problem
The existing solid-state image sensors of vertical spectral diffraction type face challenges in maintaining light collection efficiency and oblique light resistance due to the thickness of the interlayer insulating film and the constraints on the formation of the lower transparent electrode, which also limits the reduction in sensor height.
Innovation Solution
The implementation of a spectral correction buffer between the photoelectric conversion units, made of materials like quantum dots or organic materials with specific light absorption peaks, replaces the traditional spectral correction color filter, allowing for a thinner interlayer insulating film and improved light management, thereby enhancing light collection efficiency and oblique light resistance while reducing sensor height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectral correction color filter is formed in the interlayer insulating film, then color separation is improved, but the film thickness becomes large and light collection efficiency decreases
Solution Approach 1:
The spectral correction function is extracted from the interlayer insulating film by forming a dedicated spectral correction color filter layer separately. This allows the interlayer insulating film to maintain its electrical insulation function with minimal thickness, while the spectral correction layer provides the necessary color separation without adding significant thickness to the overall structure.
Solution Approach 2:
The interlayer insulating film is divided into a first interlayer insulating film layer and a second interlayer insulating film layer, with the spectral correction color filter layer positioned between them. This segmentation allows each layer to be optimized independently - the insulating layers for electrical performance and the spectral correction layer for optical performance.
2Measurement precision
If the interlayer insulating film thickness is increased to accommodate spectral correction, then color separation is improved, but light collection efficiency and oblique light resistance degrade
Solution Approach 1:
The spectral correction function is extracted from the interlayer insulating film by forming a dedicated spectral correction color filter layer separately. This allows the interlayer insulating film to maintain its electrical insulation function with minimal thickness, while the spectral correction layer provides the necessary color separation without adding significant thickness to the overall structure.
Solution Approach 2:
The spectral correction color filter layer is positioned specifically at the boundary between the first and second photoelectric conversion units, where it is most needed for color separation. This localized approach ensures that spectral correction is provided only where necessary, minimizing the impact on light collection efficiency while maintaining color separation performance.
3Measurement precision
If a spectral correction color filter is formed, then color separation is improved, but sensor height reduction is limited
Solution Approach 1:
The spectral correction color filter layer is merged with the interlayer insulating film structure, forming an integrated multi-layer configuration. This merging allows the spectral correction function to be provided without adding a separate, thick insulating layer, thereby reducing the overall sensor height while maintaining color separation performance.
Solution Approach 2:
The thickness of the spectral correction color filter layer is optimized to be smaller than conventional approaches, and the interlayer insulating film is divided into two thinner layers. This parameter optimization reduces the overall height of the sensor while maintaining the necessary spectral correction and electrical insulation functions.
4Length of moving object
If the interlayer insulating film is made thinner to reduce sensor height, then sensor height is reduced, but manufacturing precision and patterning become more difficult
Solution Approach 1:
The interlayer insulating film is segmented into a first interlayer insulating film layer and a second interlayer insulating film layer, with the spectral correction color filter layer positioned between them. This segmentation allows each layer to be formed with standard thicknesses that are easier to manufacture, while the overall structure remains compact. The segmentation also provides better adhesion and stress distribution, improving manufacturing precision.
5Shape
If CMP is used to planarize the interlayer insulating film, then surface flatness is improved, but process complexity and time increase
Solution Approach 1:
The interlayer insulating film is segmented into multiple layers with the spectral correction color filter layer positioned between them. This segmentation allows each layer to be formed with inherent flatness, reducing the need for CMP processing. The layered structure naturally provides better surface flatness without adding significant process complexity.
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 configuration suppresses decreases in light collection efficiency and degradation in oblique light resistance, enabling a reduction in sensor height and improving heat resistance and patterning margin during the formation process.
Implementation Method 1
made of materials like quantum dots or organic materials with specific light absorption peaks
Implementation Method 2
a first photoelectric conversion unit configured to perform photoelectric conversion on light in a first wavelength range
Data Source
AI summary
The present disclosure relates to a solid-state image sensor and an electronic apparatus that suppress a decrease in light collection efficiency and degradation in oblique light resistance and enable a reduction in the height of a solid-state image sensor. A solid-state image sensor according to a first aspect of the present disclosure is a solid-state image sensor of a vertical spectral diffraction type in which a plurality of photoelectric conversion units are stacked in a region of each pixel, the solid-state image sensor including: a first photoelectric conversion module that includes a first photoelectric conversion unit configured to perform photoelectric conversion on light in a first wavelength range of incident light, a first upper electrode and a first lower electrode formed with the first photoelectric conversion unit placed between the first upper electrode and the first lower electrode, and a first spectral correction unit formed between the first upper electrode and the first lower electrode to be stacked on the first photoelectric conversion unit; and a second photoelectric conversion unit configured to perform photoelectric conversion on light in a second wavelength range of light that has passed through the first photoelectric conversion module, the second wavelength range being different from the first wavelength range. The present disclosure can be applied to, for example, a CMOS image sensor.