Dual-Wiring Grounding for Solid-State Imaging Apparatus
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Solution Overview
Problem
In CMOS solid-state imaging apparatuses, a broken ground wire can lead to inconsistent electric potentials across semiconductor bases, causing vertical lines or shading in images, which deteriorate image quality and reduce yield.
Innovation Solution
A dual-wiring configuration where a first wire is extended vertically and a second wire is extended horizontally, both electrically connected to the semiconductor base, ensuring that even if one wire breaks, the other can maintain the electric potential, reducing resistance and preventing shading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single ground wire is used to connect semiconductor bases, then the wiring structure is simple, but the reliability deteriorates when the wire breaks causing pixel defects
Solution Approach 1:
The ground wire is divided into multiple segments arranged in different directions (first ground wire in vertical direction, second ground wire in horizontal direction) that are electrically connected through contact sections. This segmentation allows the system to maintain ground potential even if one segment breaks, resolving the contradiction between reliability and complexity.
Solution Approach 2:
Multiple ground wires are provided in advance as backup paths before any wire break occurs. When a wire break is detected or occurs, the alternative ground wire paths ensure continuous ground potential maintenance, preventing pixel defects. This prior cushioning approach resolves the reliability-complexity contradiction.
2Reliability
If ground wires are extended long distances to cover all pixels, then all pixels can be grounded, but the resistance increases causing potential instability
Solution Approach 1:
The grounding system is segmented into multiple shorter wire paths extending in different directions from the semiconductor base. This segmentation reduces the length of individual wires and their associated resistance while maintaining comprehensive ground coverage, resolving the contradiction between potential stability and resistance loss.
Solution Approach 2:
Ground wires are extended in multiple spatial dimensions (vertical and horizontal directions) rather than single long linear paths. This dimensional approach creates multiple shorter parallel paths that reduce overall resistance while maintaining ground potential stability across all pixels.
3Productivity
If high-speed driving is implemented to improve productivity, then output increases, but voltage pulse width decreases making timing more critical
Solution Approach 1:
Multiple ground wire paths are provided in advance to cushion against timing variations and potential signal degradation. This redundant grounding ensures stable reference potential even during high-speed operation with reduced voltage pulse widths, resolving the contradiction between productivity and timing precision.
Data Source
AI summary
Disclosed herein is a solid-state imaging apparatus including: a semiconductor base; a photodiode created on the semiconductor base and used for carrying out photoelectric conversion; a pixel section provided with pixels each having the photodiode; a first wire created by being electrically connected to the semiconductor base for the pixel section through a contact section and being extended in a first direction to the outside of the pixel section; a second wire made from a wiring layer different from the first wire and created by being extended in a second direction different from the first direction to the outside of the pixel section; and a contact section for electrically connecting the first and second wires to each other.