Fin-FET Gate Etching with Differential Gas Flow
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Solution Overview
Problem
The manufacturing process of Fin-FET devices faces challenges in creating notched gates at both the center and periphery regions, which affects device performance due to the formation of footing features at the periphery, leading to decreased performance.
Innovation Solution
A method involving the controlled etching of a gate material layer with a specific gas flow rate ratio between the center and periphery regions, allowing for the formation of notched features in both regions, which prevents the gate from being perforated by epitaxial structures and enhances device stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a planar transistor manufacturing process is used, then the manufacturing process is simple, but the device performance does not meet scaling down requirements
Solution Approach 1:
The manufacturing process is divided into multiple etching stages with different gas flow rate ratios. The first etching process uses a first gas flow rate ratio to create initial gate structures, and the second etching process uses a second gas flow rate ratio to form the final notched gate structures. This segmentation allows each stage to be optimized independently for both simplicity and performance.
Solution Approach 2:
The gas flow rate ratio is dynamically adjusted between different etching processes. By changing the gas flow rate ratio from the first value to the second value, the etching characteristics are optimized for different stages of gate formation, enabling both manufacturing simplicity and high device performance.
2Reliability
If etching is performed with uniform gas flow rate across the substrate, then the manufacturing process is simple, but footing features form at the periphery region decreasing device performance
Solution Approach 1:
Different gas flow rate ratios are applied to different regions of the substrate during etching. The first gas flow rate ratio is used for the center region while the second gas flow rate ratio is used for the periphery region. This local quality approach ensures that each region receives optimized etching conditions, preventing footing features at the periphery while maintaining proper gate structures throughout.
3Reliability
If the gate material layer is etched without regional differentiation, then the manufacturing process is simple, but the proximity distance between gate and epitaxial structures is insufficient leading to failure connections
Solution Approach 1:
The etching process is segmented into multiple stages with different gas flow rate ratios. The first etching process creates initial gate structures, and the second etching process with a different gas flow rate ratio forms notched features that increase the proximity distance. This segmentation achieves both device stability and controlled process complexity.
Solution Approach 2:
The gas flow rate ratio parameter is changed from the first value to the second value between etching processes. This parameter change enables precise control over the etching depth and profile, creating notched features that increase the proximity distance between gates and epitaxial structures, thereby preventing failure connections.
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 method ensures that both the center and periphery gates include notched features, increasing the proximity distance between the gate and epitaxial structures, thereby reducing the likelihood of failure connections and improving the overall performance and stability of the Fin-FET device.
Implementation Method 1
a gas supply device configured to supply a first flow of an etching gas to the center region and supply a second flow of the etching gas to the periphery region
Data Source
AI summary
A dry etching apparatus includes a process chamber, a stage, a gas supply device and a plasma generating device. The stage is in the process chamber and is configured to support a wafer, wherein the wafer has a center region and a periphery region surrounding the center region. The gas supply device is configured to supply a first flow of an etching gas to the center region and supply a second flow of the etching gas to the periphery region. The plasma generating device is configured to generate plasma from the etching gas.