Decoupled Plasma Nitridation Switching via Dummy Wafer Adjustment
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Solution Overview
Problem
The existing methods for switching between decoupled plasma nitridation processes with different nitrogen concentrations are time-consuming due to the 'memory effect' in semiconductor manufacturing, requiring multiple dummy wafers to adjust the nitrogen concentration in the chamber, which affects the quality and stability of gate oxide layers.
Innovation Solution
A method to quickly adjust the nitrogen concentration in the chamber by performing a nitrogen concentration adjusting process using a dummy wafer, where a process gas is ignited into plasma with RF power to remove redundant nitrogen, allowing for efficient switching between DPN processes of different doses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple dummy wafers are used to adjust nitrogen concentration in the chamber, then the memory effect is eliminated and process quality is improved, but the switching time between DPN processes increases significantly
Solution Approach 1:
The patent extracts only the essential nitridation step from the complete DPN process for the dummy wafer adjustment. Instead of performing oxide deposition, cooling, DPN doping, PNA, and cooling sequentially, the method isolates and performs only the plasma nitridation step on dummy wafers to quickly reduce nitrogen concentration in the chamber, thereby eliminating the memory effect without requiring multiple complete DPN cycles
Solution Approach 2:
The patent performs preliminary nitrogen concentration adjustment using dummy wafers before the actual production wafers are processed. By pre-adjusting the chamber nitrogen concentration through dummy wafer nitridation, the system ensures that subsequent production processes start with optimal nitrogen levels, preventing memory effect interference while maintaining tight process control
2Reliability
If a complete DPN process is performed on dummy wafers to adjust nitrogen concentration, then the nitrogen concentration is properly adjusted, but the process becomes time consuming
Solution Approach 1:
The patent segments the complete DPN process into distinct components: oxide deposition, cooling, DPN doping, PNA, and cooling. For dummy wafer-based nitrogen concentration adjustment, only the DPN doping segment is performed, while other segments are omitted. This segmentation allows rapid nitrogen concentration adjustment without the time penalty of completing full process cycles on dummy wafers
Solution Approach 2:
The patent applies partial action by performing only the necessary portion of the DPN process (the plasma nitridation step) on dummy wafers rather than the complete process. This partial execution of the DPN cycle on dummy wafers is sufficient to adjust chamber nitrogen concentration without the excessive time required for full process cycles, thereby maintaining productivity
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 significantly reduces the switching time between DPN processes, improving manufacturing efficiency by adjusting the nitrogen concentration in a shorter time, thereby enhancing the throughput and quality of semiconductor devices.
Implementation Method 1
a process gas is introduced into the chamber and ignited into plasma using RF power
Implementation Method 2
ignited into plasma using RF power
Data Source
AI summary
A method for switching decoupled plasma nitridation (DPN) processes of different doses, which is able to decrease the switching time, is provided. According to the method, a dummy wafer is inserted into a chamber, a process gas introduced is ignited into plasma, and then a DPN doping process of the next dose is performed on the dummy wafer. The nitrogen concentration of the chamber is thus adjusted rapidly to switch to the DPN process of the next dose. In addition, after several cycles of the above steps are repeated, a dummy wafer is inserted into the chamber, and a complete DPN process of the next dose is performed on the dummy wafer. This process is performed several times before switching to the next DPN process.