FinFET Source/Drain Recess Depth Control for Multi-Fin Devices
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Solution Overview
Problem
The semiconductor industry faces challenges in optimizing the integration density of electronic components due to limitations in feature size reduction, which affects the performance and efficiency of semiconductor devices like FinFETs, as existing manufacturing processes struggle to tailor source/drain recess depths for varying fin structures effectively.
Innovation Solution
A multi-cycle etching process is employed to form source/drain recesses of different depths in regions with single, double, and triple-fin devices, allowing for the formation of epitaxial source/drain regions with varying volumes, thereby improving device performance and current operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature size is reduced to improve integration density, then more components can be integrated into a given area, but manufacturing precision and process control become more difficult
Solution Approach 1:
The patent divides the source/drain formation process into multiple etching cycles, where each cycle creates recesses of specific depths in different fin regions. This segmentation allows precise control over recess depths for single-fin, double-fin, and triple-fin devices independently, resolving the manufacturing precision challenge while maintaining high integration density
Solution Approach 2:
The patent applies different etching depths and epitaxial growth conditions to different fin regions (single-fin, double-fin, triple-fin) based on their specific requirements. Each region receives localized process optimization, enabling precise control of source/drain recess characteristics tailored to each fin structure type
2Ease of manufacture
If a single etching depth is used for all fin structures, then the process is simpler, but the epitaxial source/drain regions cannot be optimized for different fin configurations
Solution Approach 1:
The etching process is segmented into multiple cycles, with each cycle targeting specific fin regions with different depth requirements. This allows the process to accommodate varying fin structures (single, double, triple fins) with optimized recess depths while maintaining a systematic and manageable manufacturing approach
Solution Approach 2:
The patent implements a dynamic, multi-stage etching process where recess depths are adjusted based on the specific fin configuration. The process adapts to different fin structures by varying etching parameters across cycles, enabling versatility while maintaining process control
3Power
If larger epitaxial source/drain regions are formed, then operating current and device performance improve, but contact resistance may increase
Solution Approach 1:
The patent optimizes epitaxial source/drain region characteristics locally for each fin type. By controlling recess depths and epitaxial growth conditions specifically for single-fin, double-fin, and triple-fin devices, the process achieves optimal balance between region size for current and contact properties for reliability
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
This approach enables the optimization of epitaxial source/drain regions for different fin structures, enhancing the operating current and performance of semiconductor devices by allowing for larger epitaxial volumes and reduced contact resistance.
Implementation Method 1
A multi-cycle etching process is employed to form source/drain recesses of different depths in regions with single, double, and triple-fin devices
Implementation Method 2
allowing for the formation of epitaxial source/drain regions with varying volumes
Data Source
AI summary
A method includes forming first devices in a first region of a substrate, wherein each first device has a first number of fins; forming second devices in a second region of the substrate that is different from the first region, wherein each second device has a second number of fins that is different from the first number of fins; forming first recesses in the fins of the first devices, wherein the first recesses have a first depth; after forming the first recesses, forming second recesses in the fins of the second devices, wherein the second recesses have a second depth different from the first depth; growing a first epitaxial source/drain region in the first recesses; and growing a second epitaxial source/drain region in the second recess.