Dual-Substrate Image Sensor Stacked Charge Storage
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Solution Overview
Problem
The challenge in semiconductor image sensors is to achieve high integration density and efficiency while minimizing device size for high-precision distance detection, particularly in laser distance measurement systems, where the limited chip area restricts the number of charge storage devices, affecting the accuracy and capacity of phase information conversion.
Innovation Solution
The solution involves a dual-substrate image sensor design where the first substrate is optimized for photoelectric conversion with N signal transmission paths connecting to N charge storage units on a second substrate, allowing for efficient transfer of photogenerated electrons and increasing storage capacity without occupying excessive chip area, thereby enhancing integration density and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pixel size is reduced to improve integration density, then the integration density and efficiency of the detection sensor are improved, but the storage capacity of charge storage devices is insufficient
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement to a three-dimensional stacked architecture by placing the photoelectric unit on one substrate and charge storage devices on another substrate in vertical layers. This dimensional change allows charge storage capacity to increase vertically without expanding the horizontal pixel area, effectively resolving the contradiction between integration density and storage capacity.
Solution Approach 2:
The patent divides the sensor into separate functional modules on different substrates: photoelectric conversion units on the first substrate and charge storage devices on the second substrate. This segmentation allows each component to be optimized independently and connected through vertical transmission paths, enabling high integration density while maintaining adequate storage capacity.
2Quantity of substance
If multiple charge storage devices are added to increase storage capacity, then the storage capacity is improved, but the chip area is occupied excessively
Solution Approach 1:
The patent utilizes the vertical dimension by stacking charge storage devices on a separate substrate above or below the photoelectric units. This allows multiple charge storage devices to be implemented without increasing the horizontal chip footprint, as they are arranged in the vertical Z-direction rather than spreading across the chip plane.
Solution Approach 2:
The patent implements a nested structure where the first substrate containing photoelectric units is positioned relative to the second substrate containing charge storage devices, with vertical transmission paths penetrating through the substrates. This nested arrangement allows charge storage devices to be 'nested' in the vertical space above/below the photoelectric layer, maximizing space utilization without expanding chip area.
3Productivity
If the device size is minimized for high distance measurement efficiency, then the distance measurement efficiency is improved, but the number of circuit devices is limited
Solution Approach 1:
The patent employs a three-dimensional stacked architecture that accommodates multiple circuit devices and transmission paths within a compact footprint. By arranging photoelectric units, transmission paths, and charge storage devices in vertical layers, the design achieves high circuit scale and complexity without increasing the horizontal device footprint, thus maintaining high distance measurement efficiency.
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 improves the integration level and reliability of the image sensor, allowing for higher storage capacity and more accurate detection results while reducing the overall device size, thus addressing the contradiction between storage capacity and pixel area.
Implementation Method 1
a photoelectric unit for photoelectric conversion
Data Source
AI summary
Provided are an image sensor and a detection system using same, which belong to the field of semiconductor image sensors. The image sensor includes: a first substrate, wherein the first substrate at least includes a photoelectric unit for photoelectric conversion, and N signal transmission channels which are connected to the photoelectric unit, with N being greater than or equal to 1; and a second substrate, which includes N second charge storage units which correspond to the N transmission channels. The transmission channels receive control signals, electrically communicate the photoelectric unit and the second charge storage units, and transfer at least some photo-induced electrons, which are generated in the photoelectric unit, to the second charge storage units. The effect of miniaturization and high integration design of pixels is ensured by means of stacking two substrates; and by means of further providing charge storage units on both of the two substrates, the area of the peripheral region of the pixels can be used, the effect of a higher charge storage amount can be achieved, and the effects such as measurement accuracy can be ensured.