Stacked Imaging Sensor Wiring Inspection With Switchable Pixel Rows
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Solution Overview
Problem
Existing imaging elements face challenges in inspecting wiring integrity and transistor quality within pixel rows and columns with a minimal number of additional circuits, particularly in stacked chip structures where needle contact terminals are impractical for extensive wiring connections.
Innovation Solution
A stacked imaging element configuration with a first substrate for pixel arrays and a second substrate for pixel control, featuring switchable connections between first and second wirings for each pixel row or column, allowing for series connections and inspections using a minimal number of circuits and electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inspection circuits are added to each pixel row or column for wiring inspection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The pixel array is divided into multiple pixel groups, with each group sharing a common inspection signal line. This segmentation allows wiring inspection for multiple pixels using fewer inspection circuits, reducing device complexity while maintaining measurement precision through group-based testing
Solution Approach 2:
The inspection signal lines serve dual purposes: they function as both signal transmission lines for pixel operation and as test paths for wiring inspection. This multi-functionality eliminates the need for separate dedicated inspection circuits, reducing device complexity while preserving measurement capability
2Measurement precision
If needle contact terminals are used for extensive wiring connections in stacked chips, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
Connection parts are introduced as intermediary elements between the first substrate (pixel array) and second substrate (control circuits). These connection parts provide accessible test points on the control circuit substrate, serving as mediators that enable external inspection equipment to access internal wiring without requiring direct needle contact with densely packed pixel terminals
Solution Approach 2:
The inspection interface is moved from the pixel array plane to the control circuit substrate plane through the stacked configuration. This dimensional transition allows inspection signals to be applied and measured at accessible locations on the control substrate, improving ease of operation while maintaining measurement precision through the established electrical connections
3Area of moving object
If stacked chip structure is used to separate pixel array and control circuits, then area of moving object is reduced, but device complexity increases
Solution Approach 1:
The pixel array and control circuits are merged into a single stacked chip structure with electrical connections between substrates. This merging reduces the overall device footprint by vertical integration while the connection parts are designed to provide both functional connectivity and inspection accessibility, managing the added complexity through multi-purpose design
Data Source
AI summary
An imaging element of the present disclosure includes a first substrate on which a pixel circuit connected to a light receiving part is formed and a second substrate on which a pixel control part that controls the pixel circuit is formed, the first substrate and the second substrate being stacked. Then, the first substrate includes a first wiring formed corresponding to a first pixel row or pixel column, a second wiring formed corresponding to a second pixel row or pixel column, a first connection part that connects the first wiring and the pixel control part, a second connection part that connects the second wiring and the pixel control part, a switch part that controls connection between the first wiring and the second wiring, a first electrode connected to the first wiring via the switch part, and a second electrode connected to the second wiring via the switch part.