Plasma Processing Gas Flow Control for Stabilization
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Solution Overview
Problem
Conventional plasma processing apparatuses face challenges in quickly stabilizing plasma after switching between different processing steps, leading to improper processing due to prolonged stabilization periods.
Innovation Solution
The apparatus includes a gas supply system, a high-frequency generating source, and a controller that switches gas species and increases the gas flow rate before energy condition changes, along with an exhaust efficiency adjusting unit to enhance gas uniformity and pressure stabilization, allowing for quicker plasma stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma is continuously generated during step switching, then particle deposition on substrate is suppressed, but plasma stabilization time is prolonged
Solution Approach 1:
The gas supply system switches gas species before the actual step transition occurs. By pre-switching the gas composition, the plasma can stabilize faster when the step transition completes, reducing stabilization time while maintaining continuous plasma generation to suppress particle deposition.
Solution Approach 2:
The system dynamically adjusts gas flow rates as a parameter during step transitions. By increasing gas flow rate during the transition period and then reducing it to a standard rate after stabilization, the plasma reaches steady state faster while maintaining the continuous plasma state needed to prevent particle deposition.
2Speed
If gas flow rate is increased during step transition, then plasma stabilization is accelerated, but gas consumption increases
Solution Approach 1:
The gas flow rate is made dynamic rather than static. The system automatically adjusts the gas flow rate based on the plasma stabilization needs during step transitions, increasing it temporarily to accelerate stabilization, then reducing it to a standard rate to minimize gas consumption during normal operation.
Solution Approach 2:
The gas flow rate follows a periodic pattern during step transitions: it is increased during the transition period when plasma stabilization is needed, then reduced to a standard rate during stable operation. This periodic adjustment achieves fast stabilization while minimizing overall gas consumption.
3Adaptability or versatility
If multiple plasma processings are switched in time series, then processing versatility is improved, but stabilization time for each step increases
Solution Approach 1:
The gas supply system performs preliminary switching of gas species before the actual processing step transition. This pre-action allows the plasma composition to begin adjusting in advance, reducing the stabilization time required when each new processing step begins, thereby enabling faster switching between multiple plasma processes.
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 reduces the plasma stabilization time, enabling more efficient and suitable plasma processing by maintaining a stable plasma state, similar to intermittent discharge processing, and minimizing particle deposition on substrates.
Implementation Method 1
a high frequency generating source configured to introduce high frequency waves for plasma generation into the processing container
Implementation Method 2
a gas supply system configured to supply a gas into the processing container
Data Source
AI summary
A controller disclosed herein drives, in a first step, a high frequency generating source at a first energy condition, and drives, in a second step, a high frequency generating source at a second energy condition. Prior to a switching time of the first step and the second step, the controller switches gas species supplied from the gas supply system into the processing container, and sets a gas flow rate in an initial period just after the switching to be larger than a gas flow rate in a stabilization period after lapse of the initial period.