Photodetector Substrate Through-Hole Layout for Uniform Pixel Timing
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Solution Overview
Problem
In photodetecting devices, the difference in wiring distance between pixels leads to variations in wiring resistance and stray capacitance, resulting in unequal signal arrival times across pixels.
Innovation Solution
A through-hole is formed in a second region of the semiconductor substrate, allowing a wire to connect the first electrode on the semiconductor substrate to the second electrode on the mount substrate, thereby minimizing the difference in wiring distance between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a wire is disposed at a notch formed at a corner of the semiconductor substrate to connect electrodes, then the device complexity is reduced, but the wiring distance from pixels to the first electrode greatly differs, causing large differences in wiring resistance and stray capacitance
Solution Approach 1:
The wire connection is extracted from the corner notch location and repositioned to pass through the center of the semiconductor substrate. This extraction from the problematic corner location eliminates the large variations in wiring distance to different pixels while maintaining the simplified wire connection approach
Solution Approach 2:
The wire connection is moved from a two-dimensional surface approach (notch at corner) to a three-dimensional approach by passing through the substrate thickness (through-hole). This dimensional change allows the wire to reach the center of the substrate, equalizing the wiring distance to all pixels on the surface
2Manufacturing precision
If the wiring distance from pixels to the first electrode is made uniform, then the difference in signal arrival time between pixels is reduced, but additional electrodes and through-holes are required, increasing device complexity
Solution Approach 1:
The through-hole at the substrate center serves multiple functions: it provides a wire connection path that equalizes wiring distance to all pixels, acts as a reference point for pixel positioning, and maintains structural integrity. This multi-functionality achieves signal arrival time uniformity without requiring additional dedicated components
Solution Approach 2:
The through-hole is formed and wire is positioned through the substrate center before pixel fabrication or wiring completion. This preliminary establishment of the central connection point ensures that all subsequent pixel wiring can be optimized relative to this fixed reference, guaranteeing uniform signal arrival times
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 the difference in signal arrival time between pixels, enhancing the temporal resolution and reducing manufacturing costs by eliminating the need for additional electrodes and through-holes.
Implementation Method 1
a wire connecting a first electrode disposed on the semiconductor substrate and a second electrode disposed on the mount substrate
Data Source
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AI summary
A semiconductor substrate IN includes a first region RS1 in which a plurality of pixels are disposed and a second region RS2 located inside the first region RS1 to be surrounded by the first region RS1 when viewed from a direction in which a principal surface INa and a principal surface 1Nb oppose each other. A through-hole TH penetrating through the semiconductor substrate IN is formed in the second region RS2 of the semiconductor substrate 1N. An electrode E3 disposed on a side of the principal surface INa of the semiconductor substrate IN and electrically connected to the plurality of pixels and an electrode E5 disposed on a side of a principal surface 20a of a mount substrate 20 are connected to each other via a bonding wire W1 inserted through the through-hole TH.