Noise-Aware Semiconductor Cell Segmentation
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Solution Overview
Problem
Current semiconductor device libraries lack noise-aware standard cells capable of reducing noise in mixed-signal and digital circuits, leading to signal integrity issues due to ground noise, power supply noise, and substrate noise.
Innovation Solution
Incorporation of noise-aware semiconductor cells with decoupling capacitor systems and multiple power and ground networks to create signal paths that reduce noise propagation, along with the use of decoupling capacitors to manage charge distribution and current flow during switching events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard cells are used in mixed-signal circuits, then circuit functionality is achieved, but noise propagates from digital to analog portions through common substrate and power/ground rails
Solution Approach 1:
The standard cell is segmented into multiple independent power and ground networks (first power network, second power network, first ground network, second ground network) that are electrically isolated from each other. This segmentation prevents noise from propagating through a single common network, as each network handles specific signal paths separately.
Solution Approach 2:
Decoupling capacitors are introduced as intermediary elements between the power networks and ground networks. These capacitors act as local energy storage and noise filtering elements, blocking high-frequency noise from propagating through the power/ground rails while maintaining DC connectivity.
2Reliability
If multiple power and ground networks are created, then noise propagation is reduced, but device complexity increases
Solution Approach 1:
The noise-aware standard cell maintains compatibility with existing standard cell libraries while adding noise reduction functionality. The cell performs its primary logic function (AND, OR, NAND, NOR, etc.) while simultaneously providing noise isolation through its multi-network structure, making it a universal solution that addresses both functionality and noise concerns.
Solution Approach 2:
The invention changes the electrical parameters of the power and ground connections by creating multiple isolated networks with different impedance characteristics. Each network can be optimized for specific frequency ranges or signal types, allowing noise reduction without fundamentally changing the cell's logic functionality.
3Reliability
If decoupling capacitors are added to manage charge distribution, then noise is reduced during switching events, but manufacturing complexity increases
Solution Approach 1:
The decoupling capacitors are merged with the standard cell structure itself rather than being separate external components. The capacitive elements are integrated into the cell's power and ground network architecture, allowing them to be fabricated using the same CMOS processing steps as the transistors and interconnects.
Solution Approach 2:
The decoupling capacitors within the standard cell provide self-service by locally storing charge and supplying current during switching events without requiring external intervention. This local charge redistribution occurs automatically within the cell structure, reducing the need for additional external decoupling components.
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
The solution effectively minimizes noise propagation into substrates, enhancing signal integrity by creating separate signal paths for noise reduction and using decoupling capacitors to manage charge and current efficiently during switching events.
Implementation Method 1
a decoupling capacitor system coupled to a power network and a ground network of the noise-aware semiconductor cell
Data Source
AI summary
Apparatus and a method are provided for reducing noise in mixed-signal and digital circuits. One apparatus (200) includes a metal-oxide-semiconductor field-effect transistor (MOSFET) (210). MOSFET (210) includes a doped substrate (2210) with a source formed proximate a substrate tie (2224) and a substrate tie (2250) adjacent substrate (2210). A ground rail (255) is coupled to the source and substrate tie (2224), and a ground rail (285) is coupled to substrate tie (2250). Ground rails (255) and (285) are configured to be coupled to different ground networks (250 and 280). One method includes producing a model of a semiconductor device including a standard semiconductor cell (710). The semiconductor cell is identified as a noise-sensitive or a noise-producing semiconductor cell (720), and the semiconductor cell is replaced with a corresponding noise-aware semiconductor cell (730).