FinFET Cut Metal Gate Protection During CMG Etching
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Solution Overview
Problem
As semiconductor devices continue to integrate more components into a given area through reduced minimum feature sizes, challenges arise in the fabrication of fin field effect transistors (FinFETs) due to the complexity of forming and patterning semiconductor fins, isolation regions, and metal gates, leading to inefficiencies in the manufacturing process.
Innovation Solution
A method for fabricating FinFETs involving the formation of fins, isolation regions, and metal gates through advanced photolithography and self-aligned processes, followed by precise etching and deposition techniques to create cut metal gates (CMGs), ensuring accurate patterning and integration of source/drain regions, and using high-k gate dielectrics and conductive materials to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but fabrication complexity and manufacturing difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple sequential stages including forming mandrels, depositing first spacers, patterning second spacers, and creating cut metal gates. Each stage builds upon the previous one, breaking down the complex task of creating high-density FinFETs into manageable steps with self-aligned processes that reduce manual intervention and improve precision at reduced feature sizes
Solution Approach 2:
Mandrel structures are formed in advance as templates before the actual fin and gate structures are created. These preliminary mandrels guide subsequent spacer formation and pattern transfer processes, ensuring accurate positioning and alignment of critical components even at reduced feature sizes, thereby managing fabrication complexity
2Quantity of substance
If minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but manufacturing precision requirements become more stringent
Solution Approach 1:
Self-aligned spacer formation processes are employed where previously deposited structures automatically serve as alignment references for subsequent layers. The first spacers align to mandrels, and second spacers align to first spacers, eliminating the need for separate alignment operations and maintaining high patterning precision even as feature sizes are reduced for increased integration density
Solution Approach 2:
The patent transitions from planar patterning to three-dimensional FinFET structures with cut metal gates. By utilizing vertical dimensionality and multi-layer spacer systems, the process achieves precise control over fin dimensions and gate positioning in reduced feature size devices, maintaining manufacturing precision while enabling higher integration density
3Manufacturing precision
If advanced photolithography and self-aligned processes are used to improve patterning accuracy, then manufacturing precision improves, but device complexity and process steps increase
Solution Approach 1:
Multiple functions are combined into integrated process steps. For example, spacer deposition and pattern transfer are merged into self-aligned processes where the same deposition and etch tools create multiple structures in sequence. The cut metal gate formation merges gate electrode creation with fin structure definition, reducing the number of separate lithography steps while maintaining high patterning accuracy
Solution Approach 2:
Spacer structures serve as intermediary elements that mediate between the lithographically defined mandrels and the final fin/gate structures. These intermediate spacers enable precise pattern transfer through self-aligned etching processes, achieving high patterning accuracy while consolidating multiple operations into a streamlined process flow
4Reliability
If cut metal gates and high-k gate dielectrics are implemented to enhance device performance, then transistor performance improves, but fabrication process complexity increases
Solution Approach 1:
The patent employs parameter changes in material properties and deposition conditions to achieve cut metal gate and high-k dielectric formation. By controlling deposition temperatures, pressures, and material compositions, the process creates functionally distinct regions (conductive gates vs. insulating dielectrics) within a unified fabrication flow, enhancing device performance while managing process complexity through material science rather than additional process steps
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 method enables efficient and precise fabrication of FinFETs, improving integration density and performance by ensuring accurate formation of CMGs and source/drain regions, thereby enhancing the overall semiconductor device's functionality and reliability.
Implementation Method 1
semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of material over a semiconductor substrate
Implementation Method 2
sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of material
Implementation Method 3
patterning the various material layers using lithography to form circuit components and elements thereon
Data Source
AI summary
A semiconductor device including a fin field effect transistor (FinFET) with a cut metal gate (CMG) and a method of manufacturing the semiconductor device are described herein. The method includes forming a CMG protective helmet structure at a top portion of a CMG dummy gate plug formed within a semiconductor substrate. The CMG protective helmet structure prevents consumption and damage of a dummy filler material in a CMG region and prevents undesirable polymer/residue byproducts from forming on top surfaces of epitaxial regions of the FinFET during etching processes.