FinFET Adhesion Sheath for Isolation and Metal Integration

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Solution Overview

Problem

As semiconductor devices continue to shrink, traditional planar transistor structures face challenges in maintaining operation speed, leading to the development of non-planar structures like FinFETs with elevated vertical fins. However, these structures require precise manufacturing processes to ensure effective gate stack formation, spacer creation, and metal connector integration, which is complicated by the need for precise etching and isolation to maintain device performance and reliability.

Innovation Solution

The manufacturing process for FinFET devices involves forming a gate stack structure on a substrate with spacers, followed by a dielectric layer and metal connectors. A conformal adhesion layer is used to form sheath structures within contact openings, which exposes the source and drain regions while maintaining isolation, allowing for accurate metal connector placement and enhancing device reliability and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If traditional planar transistor structures are used, then manufacturing process is simpler, but operation speed decreases as gate width and channel length shrink

Engineering Contradiction:
Improveoperation speedVSAvoidtransistor structure complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent transitions from planar two-dimensional transistor structures to three-dimensional FinFET structures with vertical fins. This dimensional change allows the gate to control the channel from three sides, improving carrier control and operation speed while accommodating continued scaling of gate dimensions without proportionally increasing manufacturing complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If FinFET structures with elevated vertical fins are used, then operation speed increases, but manufacturing precision requirements increase

Engineering Contradiction:
Improveoperation speedVSAvoidgate stack formation precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent employs preliminary patterning steps including mandrel formation and spacer deposition before final gate stack definition. These preliminary structures serve as templates that guide subsequent etching and deposition processes, ensuring precise FinFET gate stack formation while reducing the complexity of direct high-precision patterning

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediate structures such as spacers and mandrels that mediate between the patterning process and final gate stack formation. These intermediary elements enable indirect definition of critical dimensions, relaxing direct lithography precision requirements while maintaining fine feature size control

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If FinFET structures with elevated vertical fins are used, then operation speed increases, but device isolation and connector integration become more complicated

Engineering Contradiction:
Improveoperation speedVSAvoidisolation and connector integration complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent segments the device structure into distinct functional regions with dedicated dielectric layers for isolation between gate stacks and around contact openings. This segmentation allows independent optimization of isolation structures from active device regions, simplifying the integration of metal connectors while maintaining FinFET performance

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS9997632B2Fin-type field effect transistor device and manufacturing method thereof
Publication Date: 2018.06.12 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A fin-type field effect transistor device including a substrate, at least one gate stack structure, spacers and source and drain regions is described. The gate stack structure is disposed on the substrate and the spacers are disposed on sidewalls of the gate stack structure. The source and drain regions are disposed in the substrate and located at opposite sides of the gate stack structures. A dielectric layer having contact openings is disposed over the substrate and covers the gate stack structures. Metal connectors are disposed within the contact openings and connected to the source and drain regions, and adhesion layers are sandwiched between the contact openings and the metal connectors located within the contact openings.