3D FinFET Modeling for Voltage Threshold Variation

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Solution Overview

Problem

Current electronic device design tools, such as spice tools, primarily focus on 2D layouts and do not account for the gate height of 3D transistors like FinFETs, leading to variations in fin heights among devices, which result in mismatched electrical characteristics and voltage thresholds.

Innovation Solution

A 3D modeling method is introduced that considers gate height, fin width, and fin length to create a 3D FinFET model, allowing for the detection and modification of design layouts to minimize fin height variations and improve electrical characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If 2D layout modeling is used for FinFET devices, then design simplicity is maintained, but fin height variations cause mismatched electrical characteristics

Engineering Contradiction:

Improvemodeling complexityVSAvoidelectrical characteristic consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent transitions from 2D layout modeling to 3D modeling by incorporating the fin height dimension (z-direction) into the model. This allows the modeling tool to account for variations in fin height that affect electrical characteristics, thereby improving reliability while maintaining reasonable complexity through automated extraction methods

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If 3D modeling incorporating gate height is implemented, then electrical characteristic accuracy is improved, but device complexity and modeling difficulty increase

Engineering Contradiction:

Improveelectrical characteristic measurement accuracyVSAvoidmodeling complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual 3D modeling processes with an automated system that extracts fin height information from cross-sectional images using image processing algorithms. This substitution of automated computational methods for manual processes improves measurement precision while managing modeling complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If fin height variations are not accounted for, then design process remains simple, but voltage threshold mismatches occur

Engineering Contradiction:

Improvedesign process simplicityVSAvoidvoltage threshold consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent performs preliminary extraction of fin height information from cross-sectional images during the design phase, before fabrication. This allows designers to account for fin height variations in the modeling stage, ensuring voltage threshold consistency without complicating the manufacturing process

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9582633B23D device modeling for FinFET devices

Publication Date: 2017.02.28 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Among other things, techniques and systems for 3D modeling of a FinFET device and for detecting a variation for a design layout based upon a 3D FinFET model are provided. For example, a fin height of a FinFET device is determined based upon imagery of the FinFET device. The fin height and a 2D FinFET model for the FinFET device are used to create a 3D FinFET model. The 3D FinFET model takes into account the fin height, which is evaluated to identify fin height variations amongst FinFET devices within the design layout. For example, a fin height variation is determined based upon a proximity pattern density, a fin pitch, a gate length, or other parameters/measurements. A voltage threshold variation is determined based upon the fin height variation. This allows the design layout to be modified to decrease the variation.