Semiconductor Capping Layer Thickness Ratio for Etching Control
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing complex three-dimensional transistor structures, such as FinFETs, due to increased complexity and inefficiencies in processing and manufacturing as a result of scaling down ICs, which affects production efficiency and costs.
Innovation Solution
A semiconductor device structure is formed using fin structures, epitaxial layers, and a capping layer with specific thickness ratios to optimize the source/drain structure and reduce losses during etching, improving device performance by minimizing the difference in etching between different surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If three-dimensional transistor structures (FinFETs) are introduced to replace planar transistors, then functional density is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the capping layer into two distinct portions with different thicknesses - a first portion and a second portion - to address the manufacturing complexity of FinFET structures. This segmentation allows selective etching of the source/drain structure while preserving the fin structure, thereby managing the complexity of three-dimensional transistor fabrication.
Solution Approach 2:
The patent applies local quality by creating a capping layer with non-uniform thickness distribution - the first portion has a different thickness than the second portion. This local variation in thickness enables selective removal of source/drain material while maintaining the fin structure integrity, directly addressing the manufacturing challenges of high-density three-dimensional transistors.
2Ease of manufacture
If the capping layer has uniform thickness, then ease of manufacture is improved, but source/drain structure loss during etching increases
Solution Approach 1:
The patent implements local quality by forming a capping layer with different thicknesses in different regions - the first portion and second portion have distinct thickness values. This non-uniform thickness distribution is specifically designed to protect the source/drain structure during etching while maintaining ease of manufacture through a single deposition process followed by selective removal.
Solution Approach 2:
The patent applies preliminary action by forming the capping layer with predetermined non-uniform thickness before the etching process. This pre-configured thickness variation serves as a protective mechanism that prevents excessive source/drain structure loss during subsequent etching operations, while the capping layer itself can be removed afterward.
3Productivity
If scaling down is continued to increase functional density, then production efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the capping layer into portions with different thicknesses to enable selective etching at scaled dimensions. This segmentation approach allows the manufacturing process to maintain control and efficiency even as device dimensions are reduced to increase functional density, by providing a structured method for selective material removal.
Solution Approach 2:
The patent utilizes parameter changes by varying the thickness of the capping layer in different regions. This parameter variation enables precise control over the etching process at scaled dimensions, allowing production efficiency to be maintained while managing the increased complexity inherent in miniaturized three-dimensional transistor structures.
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 approach enhances the performance of semiconductor devices by reducing the loss of source/drain structures during etching, leading to improved manufacturing efficiency and reduced costs, while maintaining the complexity and density of advanced IC designs.
Implementation Method 1
etching the capping layer to expose the source/drain structure
Data Source
AI summary
Methods of fabricating a semiconductor device structure are provided. The method includes forming a fin structure over a substrate. The method also includes forming a gate structure over the fin structure. The method further includes epitaxially growing a source/drain structure covering the fin structure. In addition, the method includes epitaxially growing a capping layer over the source/drain structure. The capping layer has a top portion and a lower portion under the top portion. The top portion has a first thickness and the lower portion has a second. A ratio of the first thickness to the second thickness is in a range of about 1.01 to about 2. The method also includes etching the top portion and the lower portion of the capping layer. The method further includes forming a silicide layer over the source/drain structure and a contact over the silicide layer.