Nano-Sheet Power Domains With Shared N-Well Spacing Relief
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Solution Overview
Problem
Bulk semiconductor technologies require separate n-wells for multiple power domains, leading to spacing penalties and inefficiencies in IC structure fabrication, particularly with level shifters, as the minimum n-well spacing does not scale proportionally with lower gate lengths.
Innovation Solution
The use of nano-sheet structures that are either non-intersecting or sharing the same n-well region, allowing for closer spacing between power domains, with nano-sheet structures coupled to backend metals and backside vias for efficient power delivery and reduced leakage between power supply domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate n-wells are used for multiple power domains, then power domain isolation is achieved, but die area increases due to spacing penalties
Solution Approach 1:
Multiple nano-sheet devices belonging to different power domains share a common n-well region, eliminating the need for separate n-wells and the spacing between them. This merging approach reduces die area while maintaining power domain isolation through the selective coupling of nano-sheet structures to different power supply voltages via backend metals and backside vias.
Solution Approach 2:
The patent utilizes vertical stacking of nano-sheet structures in the third dimension, allowing multiple power domains to be integrated within a shared n-well. Power delivery is achieved through backend metals and backside vias, transitioning from planar separation to three-dimensional integration, thereby reducing die area overhead.
2Ease of manufacture
If minimum n-well spacing is maintained, then manufacturing constraints are satisfied, but power delivery efficiency decreases
Solution Approach 1:
The patent merges multiple n-well regions into a single shared n-well that accommodates nano-sheet devices from different power domains. This eliminates the minimum spacing requirement between n-wells while maintaining manufacturing compliance through proper nano-sheet and backend metal design, thereby enabling closer spacing and improved power delivery efficiency.
Solution Approach 2:
Backend metals and backside vias serve as intermediaries for power delivery, allowing efficient power distribution to nano-sheet devices within the shared n-well without requiring physical proximity of separate n-wells. This intermediary approach decouples power delivery efficiency from n-well spacing constraints.
3Area of stationary object
If nano-sheet structures are placed closer together, then die area is reduced, but leakage between power domains increases
Solution Approach 1:
The patent combines multiple power domain nano-sheet devices into a shared n-well structure, reducing die area. Power domain isolation is maintained through selective coupling mechanisms where specific nano-sheet structures are connected to different power supply voltages via backend metals and backside vias, preventing leakage despite close spacing.
Solution Approach 2:
Backend metals and backside vias act as controlled intermediaries that enable or disable power delivery to specific nano-sheet structures. This selective coupling prevents unwanted leakage between power domains while allowing close placement of nano-sheet devices within the shared n-well, thus reducing die area without increasing leakage.
Data Source
AI summary
One aspect of this description relates to an integrated circuit (IC) structure including a first layer and a second layer. The first layer includes a first metal structure coupled to a first power supply having a first voltage level and a second metal structure coupled to a second power supply having a second voltage level different from the first voltage level. The second layer is formed over the first layer. The second layer includes a first nano-sheet device coupled to the first metal structure and a second nano-sheet device adjacent to the first nano-sheet device. The second nano-sheet device is coupled to the second metal structure. A distance between the first nano-sheet device and the second nano-sheet device is less than a minimum n-well to n-well spacing.