ESD FinFET Drain Region Segmentation for Metal Landing
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Solution Overview
Problem
Conventional FinFET devices used for electrostatic discharge (ESD) protection face issues with poor epitaxial growth and metal contact landing due to the longer drain region, leading to degraded device performance and potential failures, especially as semiconductor sizes are scaled down.
Innovation Solution
The fabrication process is modified by breaking up the mandrels in the drain region to prevent fin structures from forming, allowing for improved epitaxial growth and smoother surfaces, and an implantation process is used to enhance the etching rate of the dielectric layer, ensuring better metal contact landing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drain region is made wider for ESD protection, then ESD protection capability is improved, but epitaxial growth quality deteriorates and metal contact landing becomes poor
Solution Approach 1:
The drain region is segmented into two distinct zones: a first drain region with fin structures for epitaxial growth and a second drain region without fin structures for metal contact formation. This segmentation allows each zone to be optimized independently - the first region provides good epitaxial growth while the second region enables reliable metal contact landing, thus resolving the contradiction between ESD protection capability and manufacturing precision
2Reliability
If the drain region is made wider for ESD protection, then ESD protection capability is improved, but metal contact landing quality deteriorates
Solution Approach 1:
The drain region is divided into a first drain region for epitaxial growth and a second drain region for metal contact formation. The second region is specifically designed without fin structures to provide a flat surface that ensures good metal contact landing, while the overall wider drain region maintains ESD protection capability
Solution Approach 2:
Different regions of the drain are given different structural qualities - the first drain region has fin structures optimized for epitaxial growth while the second drain region has a planar structure optimized for metal contact landing. This local differentiation allows each area to perform its specific function optimally
3Productivity
If conventional FinFET fabrication is used, then device density is achieved, but device performance degrades due to poor metal contact connection
Solution Approach 1:
The drain region is segmented into functional zones with different structures - the first region maintains the FinFET density benefits while the second region provides optimized metal contact landing. This segmentation allows the device to achieve both high density and reliable performance
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 results in improved epitaxial growth and metal contact quality in the drain region, enhancing device performance and yield by preventing fin structures in the drain area and promoting smoother, thicker epi-layers for better electrical connections.
Implementation Method 1
an implantation process is used to enhance the etching rate of the dielectric layer
Implementation Method 2
improved epitaxial growth and metal contact quality in the drain region
Data Source
AI summary
A mandrel is formed over an active region that includes a first region and a second region. The first region and the second region are reserved for the formation of a source and a drain of a FinFET, respectively. A portion of the mandrel formed over the second region is broken up into a first segment and a second segment separated from the first segment by a gap. Spacers are formed on opposite sides of the mandrel. Using the spacers, fins are defined. The fins protrude upwardly out of the active region. A portion of the second region corresponding to the gap has no fins formed thereover. The source is epitaxially grown on the fins in the first region. At least a portion of the drain is epitaxially grown on the portion of the second region having no fins.