FinFET Merged Source-Drain Epitaxy and Etching
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Solution Overview
Problem
The semiconductor industry faces challenges in fabricating FinFET devices with merged epitaxial source/drain structures due to the complexity of forming high-density transistor arrays with precise control over epitaxial growth and spacing, which affects device performance and density.
Innovation Solution
A method for manufacturing FinFET devices involving the formation of merged epitaxial source/drain structures by epitaxial growth over recessed fin structures, where the epitaxial source/drain structures are intentionally merged and then separated using etching techniques to achieve closer transistor spacing and improved device density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional separate source/drain formation is used, then manufacturing process is simpler, but device density is lower
Solution Approach 1:
The patent merges the source and drain epitaxial growth processes into a single continuous growth step, forming a merged epitaxial source/drain structure that spans across adjacent fin structures. This merging eliminates the need for separate formation processes for each source/drain region, thereby simplifying the manufacturing process while enabling closer transistor spacing and higher device density
Solution Approach 2:
After forming the merged epitaxial source/drain structure, the patent uses selective etching to segment and separate the structure into individual source and drain regions for each transistor. This segmentation approach allows the structure to be formed as one continuous piece first (simplifying growth), then divided into functional segments (achieving proper device isolation), thus resolving the contradiction between simplicity and functionality
2Productivity
If transistors are spaced closer together, then device density increases, but control over epitaxial growth and spacing becomes more difficult
Solution Approach 1:
The patent forms a unified merged epitaxial source/drain structure before performing selective removal to create individual source and drain regions. By establishing the continuous structure first with uniform epitaxial growth conditions, the process ensures precise spacing and alignment is achieved during the growth phase, while subsequent selective etching creates the final separated structure. This preliminary formation of the merged structure eliminates the need to control spacing during multiple separate growth steps
Solution Approach 2:
The merged epitaxial source/drain structure serves as an intermediary form between the initial substrate state and the final separated source/drain configuration. This intermediate merged structure allows uniform epitaxial growth across multiple fins with precise spacing, then enables selective removal to create the final separated structure. The intermediary merged form acts as a buffer that decouples the precision requirements of growth from the final separation geometry
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 allows for increased device density by enabling transistors to be formed closer together, enhancing performance by optimizing the epitaxial source/drain structure formation and separation process, thereby improving the overall manufacturing efficiency and device characteristics.
Implementation Method 1
sources and drains are formed by using an epitaxial growth method
Implementation Method 2
the epitaxial source/drain structures are intentionally merged and then separated using etching techniques
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a first transistor structure and a second transistor structure on a substrate, wherein source/drain structures of the first transistor structure and the second transistor structure are merged. The first and second transistor structures are separated by etching the source/drain structures.