MOSFET Active Region Layout Using Bridging Polysilicon Contact

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Solution Overview

Problem

The performance of semiconductor devices like MOSFETs is limited by the size of the transistor, with larger transistors offering better performance but conflicting with industry demands for smaller devices, resulting in an area penalty due to the conventional arrangement of polysilicon contacts outside active regions.

Innovation Solution

The polysilicon contact is positioned within the active region of the MOSFET, allowing for increased transistor size without area penalties and enhanced metal routing flexibility, by bridging the polysilicon and metal contacts within the active region, thereby expanding the active region size and improving performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transistor size is increased to improve performance, then the performance of the MOSFET is improved, but the area occupied by the device increases

Engineering Contradiction:

ImproveperformanceVSAvoiddevice area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent repositions the polysilicon contact from a conventional location outside the active region to a location within the active region, utilizing the two-dimensional layout space more efficiently. This dimensional reconfiguration allows the active region to extend further without increasing the overall device footprint, effectively resolving the contradiction between performance (which requires larger active regions) and area occupation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the polysilicon contact is positioned outside the active region (conventional layout), then the manufacturing process is simplified, but the active region size is reduced

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidactive region size

Core Design Contradiction:

Ease of manufactureVSArea of moving object

Solution Approach 1:

The patent inverts the conventional layout arrangement by placing the polysilicon contact inside the active region rather than outside. This inversion challenges the traditional design paradigm and enables the active region to utilize its full potential area, improving device performance without complicating the manufacturing process, as the contact alignment can be achieved through standard photolithography techniques.

Inventive Principle:

Principle #13The other way round (Inversion)

3Area of moving object

If the polysilicon contact is positioned within the active region, then the active region size is increased, but the metal routing complexity increases

Engineering Contradiction:

Improveactive region sizeVSAvoidmetal routing complexity

Core Design Contradiction:

Area of moving objectVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary polysilicon contact structure that bridges the metal contacts and the active region. This intermediary element simplifies the metal routing by providing a dedicated contact point within the active region, eliminating the need for complex metal interconnections and via structures that would otherwise be required to access the enlarged active region.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9691666B2Layout architecture for performance improvement

Publication Date: 2017.06.27 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An integrated circuit is provided. The integrated circuit includes a first contact disposed over a first source/drain region, a second contact disposed over a second source/drain region, a polysilicon disposed over a gate, the polysilicon interposed between the first contact and the second contact, a first polysilicon contact bridging the polysilicon and the first contact within an active region, and an output structure electrically coupled to the first polysilicon contact.