Stacked Solid-State Imaging Layout for One-Shot Exposure Alignment
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Solution Overview
Problem
The manufacturing process of solid-state imaging devices with stacked structures is complex and costly due to the need for separate exposure and high-precision alignment of different photomasks across separated regions.
Innovation Solution
A solid-state imaging device is designed with a first substrate having a pixel circuit and a second substrate with signal processing circuits, where the signal processing circuits are arranged adjacent to each other with a spacing region, allowing for a stacked structure that simplifies the manufacturing process by using one-shot exposure and overlapping scribe regions for alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If separate exposure is used for manufacturing solid-state imaging devices with area greater than exposure range, then the device can be manufactured, but the manufacturing process becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent transitions from planar manufacturing to three-dimensional stacked structure. By forming pixel circuits and signal processing circuits on separate substrates and stacking them vertically, the device achieves greater functional area without requiring proportionally larger exposure areas, thereby simplifying the manufacturing process and reducing costs.
Solution Approach 2:
The patent divides the solid-state imaging device into separate functional modules (pixel circuits on one substrate, signal processing circuits on another substrate). This segmentation allows each substrate to be manufactured independently within the exposure range of standard equipment, avoiding the need for complex separate exposure processes while maintaining the overall device functionality.
2Area of stationary object
If separate exposure is used for separated regions, then the device can be manufactured, but different photomasks are required and manufacturing cost increases
Solution Approach 1:
The patent combines multiple circuit functions (pixel circuits and signal processing circuits) that would traditionally require separate exposure processes and different photomasks. By implementing both on stacked substrates with compatible single-layer wiring structures, the manufacturing process can use the same photomask and exposure settings, significantly reducing manufacturing costs.
Solution Approach 2:
The patent creates a universal manufacturing approach where the same exposure process and photomask can be used for both pixel circuit substrates and signal processing circuit substrates. This universality is achieved through standardized single-layer wiring designs and compatible fabrication processes, eliminating the need for multiple specialized photomasks and reducing overall manufacturing expenses.
3Manufacturing precision
If high-precision alignment is used for portions connecting separated regions, then the device can be manufactured, but the manufacturing process becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent incorporates alignment marks and positioning structures during the substrate fabrication process itself, before the stacking operation. This preliminary preparation of alignment features simplifies the subsequent stacking process, reducing the complexity of high-precision alignment operations and lowering manufacturing costs while maintaining the required alignment precision.
Data Source
AI summary
There is provided a solid-state imaging device including a first substrate having a pixel circuit including a pixel array unit formed thereon, and a second substrate having a plurality of signal processing circuits formed thereon so as to be arranged through a scribe region. The first substrate and the second substrate are stacked.