SGT Pillar Height Control via Plasma Emission Monitoring
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Solution Overview
Problem
The existing production methods for Surrounding Gate Transistors (SGTs) face challenges in stabilizing the height dimension of pillar-shaped semiconductor layers and gate lengths due to fluctuations in etching rates, leading to inconsistent transistor characteristics across wafers and production lots, as they lack end-point detection processes based on plasma emission intensity monitoring.
Innovation Solution
The method involves using protective films with distinct plasma emission characteristics to monitor plasma emission intensity during dry etching, allowing for precise detection of etching end-points for both pillar-shaped silicon layers and gate electrodes, thereby stabilizing their dimensions and ensuring consistent transistor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dry etching with fixed etching time is used, then the production process is simple, but the height dimension of pillar-shaped semiconductor layer fluctuates due to etching rate variations
Solution Approach 1:
The patent implements feedback control by monitoring plasma emission intensity during dry etching. The system detects the etching end-point in real-time based on plasma emission characteristics, and adjusts the etching process accordingly. This feedback mechanism stabilizes the height dimension of pillar-shaped semiconductor layers by compensating for etching rate fluctuations, resolving the contradiction between manufacturing precision and process simplicity.
2Manufacturing precision
If conventional dry etching with fixed etching time is used, then the production process is simple, but the gate length fluctuates due to etching rate variations
Solution Approach 1:
The patent applies feedback control to gate length control by monitoring plasma emission intensity during the etching process. The system detects when the gate electrode etching reaches the desired length based on plasma emission characteristics, ensuring consistent gate length across different production lots. This resolves the contradiction by maintaining manufacturing precision without requiring complex manual intervention.
3Manufacturing precision
If end-point detection based on plasma emission intensity monitoring is implemented, then etching precision is improved, but the production process becomes more complex
Solution Approach 1:
The patent employs self-service automation where the etching process monitors and controls itself through plasma emission intensity detection. The system automatically detects etching end-points and adjusts process parameters without requiring external intervention or complex additional equipment. This self-service approach improves etching precision while minimizing the increase in overall process complexity.
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 enables accurate control of etching amounts, resulting in SGTs with stable height dimensions and gate lengths, which minimizes fluctuations in transistor characteristics, leading to more consistent and reliable semiconductor device production.
Implementation Method 1
the second protective film has a plasma emission characteristic different from that of the first protective film
Implementation Method 2
an intensity of plasma emission generated from the second protective film is monitored during the etching to detect a change in the plasma emission intensity
Data Source
AI summary
In a conventional SGT production method, during dry etching for forming a pillar-shaped silicon layer and a gate electrode, an etching amount cannot be controlled using an end-point detection process, which causes difficulty in producing an SGT while stabilizing a height dimension of the pillar-shaped silicon layer, and a gate length. In an SGT production method of the present invention, a hard mask for use in dry etching for forming a pillar-shaped silicon layer is formed in a layered structure comprising a first hard mask and a second hard mask, to allow the end-point detection process to be used during the dry etching for the pillar-shaped silicon layer. In addition, a gate conductive film for use in dry etching for forming a gate electrode is formed in a layered structure comprising a first gate conductive film and a second gate conductive film, to allow the end-point detection process to be used during the dry etching for the gate electrode.