Semiconductor Contact Structure With Asymmetric Source/Drain Layout
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Solution Overview
Problem
Existing semiconductor devices face challenges in forming metal contacts without leaving residues or empty spaces, which can damage the lower source/drain pattern and etch stop layer, and result in increased capacitance due to overlapping areas.
Innovation Solution
The semiconductor device employs a method of forming semiconductor devices by creating asymmetric shapes in the semiconductor device, including forming a semiconductor device with asymmetrically shaped lower source/drain patterns and using lateral epitaxial growth to form contacts, which reduces damage and residue, and improves capacitance by minimizing overlapping areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal contact formation is used, then contact connectivity is achieved, but residues or empty spaces remain causing damage to lower source/drain pattern and etch stop layer
Solution Approach 1:
The method performs preliminary actions by forming a mandrel structure and performing lateral epitaxial growth before final contact formation. This preparatory sequence creates a controlled framework that guides subsequent metal deposition, ensuring complete filling without residues or empty spaces that would otherwise damage the lower source/drain pattern and etch stop layer.
Solution Approach 2:
The patent introduces intermediate structures (mandrel and epitaxially grown layers) that mediate between the contact formation process and the underlying sensitive layers. These intermediary elements control the metal deposition process, preventing direct harmful interactions with the lower source/drain pattern and etch stop layer while ensuring complete contact filling.
2Reliability
If conventional contact formation is used, then contact connectivity is achieved, but overlapping areas increase capacitance
Solution Approach 1:
The patent employs asymmetric contact hole shapes and positioning strategies that minimize the overlapping area between contact structures and gate patterns. By deliberately designing non-symmetric contact geometries, the method reduces parasitic capacitance while maintaining adequate electrical connectivity, thereby reducing energy loss in the device.
3Manufacturing precision
If asymmetric shapes are used in lower source/drain pattern, then contact filling is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into distinct stages: forming the mandrel structure, performing lateral epitaxial growth, and final contact filling. This segmentation transforms the complex task of creating asymmetric contacts into a series of simpler, more controllable steps, where each stage contributes a specific geometric feature that accumulates to form the final asymmetric contact shape.
Solution Approach 2:
The patent replaces direct mechanical patterning of asymmetric contact shapes with a self-organizing chemical process (lateral epitaxial growth). Instead of using complex lithography and etching to create asymmetric geometries, the method allows the material to grow laterally from the mandrel structure, naturally forming the desired asymmetric shapes through controlled chemical vapor deposition.
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 method effectively fills metal contacts without residues or empty spaces, reduces damage to the lower source/drain pattern and etch stop layer, and enhances capacitance by minimizing overlapping areas.
Implementation Method 1
The lower contact portion extending in the first direction, an upper contact portion connected to the lower contact portion, and the upper contact portion extending in a third direction
Data Source
AI summary
Provided is a semiconductor device that includes a first active pattern and a second active pattern on a substrate, the first active pattern spaced apart from the second active pattern in a first direction, and extending in a second direction, the second direction being different from the first direction, a lower channel pattern and a lower source/drain pattern on the first active pattern and alternately arranged in the second direction, an upper channel pattern on the lower channel pattern, and an upper source/drain pattern on the lower source/drain pattern, a gate pattern on first active pattern, the lower channel pattern, and the upper channel pattern, and a first active contact connected to the lower source/drain pattern, and a second active contact connected to the upper source/drain pattern.