Solid-State Image Sensor Side-Mounted Wiring for Light Sensitivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid-state image sensors face challenges in achieving sufficient sensitivity due to the limited light-receiving area caused by transistors and wiring patterns located on the light-receiving side, which becomes exacerbated as pixel size decreases.
Innovation Solution
The solution involves a configuration where the wiring patterns are positioned on one side of the semiconductor substrate, and the microlenses are on the opposite side, allowing for a larger light-receiving area and improved sensitivity by ensuring that light is not intercepted by the wiring patterns, and circuit elements are strategically placed to avoid reducing the light-receiving region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transistors and wiring patterns are located on the light-receiving face side to enable pixel circuit integration, then device integration is achieved, but the light-receiving area is limited and sensitivity deteriorates
Solution Approach 1:
The patent applies dimensionality change by moving the pixel circuit from the light-receiving face (2D plane) to the side surface of the semiconductor substrate (3D spatial arrangement). This allows the light-receiving face to be fully dedicated to light reception while circuits are positioned on the side, effectively resolving the area conflict through spatial reconfiguration.
Solution Approach 2:
The patent extracts the pixel circuit components (transistors and wiring patterns) from the light-receiving face and relocates them to the side surface of the semiconductor substrate. This separation removes the harmful factor (circuit components blocking light) from the light-receiving area while maintaining circuit functionality.
2Measurement precision
If pixel size is reduced to increase pixel density, then resolution is improved, but light-receiving area per pixel decreases and sensitivity deteriorates
Solution Approach 1:
By relocating circuits to the side surface, the patent enables larger photoelectric converters on the light-receiving face even at reduced pixel sizes. The side-surface circuit positioning removes the area constraint, allowing each pixel to maintain adequate light-receiving area while achieving high pixel density through smaller pixel dimensions.
3Device complexity
If wiring patterns are positioned on the light-receiving side to simplify interconnect routing, then routing complexity is reduced, but light interception by wiring increases and sensitivity deteriorates
Solution Approach 1:
The patent extracts wiring patterns from the light-receiving face and positions them on the side surface of the semiconductor substrate. This removal eliminates the harmful light interception effect while the wiring still provides necessary interconnect functionality, as demonstrated by the side-surface wiring layout in the embodiments.
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 enhances the sensitivity of the solid-state image sensor by increasing the light-receiving area and maintaining it even with the presence of circuit elements, thereby improving the detection capabilities.
Implementation Method 1
each pixel having a photoelectric converter formed in the semiconductor substrate
Implementation Method 2
a plurality of microlenses which are located so that one microlens is arranged for each pixel group
Data Source
AI summary
An image sensor includes a semiconductor substrate having first and second faces. The sensor includes a plurality of pixel groups each including pixels, each pixel having a photoelectric converter and a wiring pattern, the converter including a region whose major carriers are the same with charges to be accumulated in the photoelectric converter. The sensor also includes a microlenses which are located so that one microlens is arranged for each pixel group. The wiring patterns are located at a side of the first face, and the plurality of microlenses are located at a side of the second face. Light-incidence faces of the regions of the photoelectric converters of each pixel group are arranged along the second face such that the light-incidence faces are apart from each other in a direction along the second face.