Solid-State Imaging Device Stacked Substrates Overflow Drain
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Solution Overview
Problem
Solid-state imaging devices with stacked structures face challenges in reducing size while maintaining light reception area, as process constraints require forming wires and contact portions on the light reception surface, potentially decreasing the light reception area.
Innovation Solution
A three-dimensional structure is implemented where substrates are stacked via a wiring layer or insulation layer, with contact portions connected to the non-light incident surface, allowing voltage to be supplied from the wiring layer to the light sensing section without increasing pixel area or decreasing light reception area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires and contact portions are formed on the light reception surface to supply voltage to the light sensing section, then the device can function properly, but the light reception area is decreased
Solution Approach 1:
The patent transitions from a two-dimensional planar structure to a three-dimensional stacked structure. The light sensing section is formed on a first substrate, while the wiring layer supplying voltage is formed on a second substrate stacked above the first substrate. This vertical arrangement allows voltage supply without occupying the light reception area on the first substrate, resolving the contradiction between functional operation and light reception area.
2Volume of moving object
If a three-dimensional stacked structure is employed to reduce device size, then the overall device footprint is reduced, but wires and contact portions must still be formed on the light reception surface due to process constraints
Solution Approach 1:
The invention utilizes the third dimension (vertical stacking) to separate the light sensing function from the voltage supply function. By forming the wiring layer on a stacked second substrate rather than on the light reception surface, the device achieves compact footprint while preserving full light reception area, overcoming the process constraint that would otherwise require surface-mounted contacts.
3Volume of moving object
If substrates are stacked via wiring layer or insulation layer, then device size is reduced without increasing pixel area, but the complexity of forming contact portions connecting to non-light incident surface increases
Solution Approach 1:
The patent divides the device into separate functional substrates: a first substrate for light sensing and a second substrate for wiring. This segmentation allows each substrate to be optimized independently and simplifies the formation of contact portions, as they only need to connect corresponding elements between adjacent stacked substrates rather than routing across the entire device area.
Data Source
AI summary
A solid-state imaging device includes: a plurality of substrates stacked via a wiring layer or an insulation layer; a light sensing section that is formed in a substrate, of the plurality of substrates, disposed on a light incident side and that generates a signal charge in accordance with an amount of received light; and a contact portion that is connected to a non-light incident-surface side of the substrate in which the light sensing section is formed and that supplies a desired voltage to the substrate from a wire in a wiring layer disposed on a non-light incident side of the substrate.