Plasma Processing Apparatus Heat-Transfer Gas Pressure Control
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in maintaining consistent wafer surface temperature distribution due to individual differences in the surface properties of the heat-transfer gas flow channel and changes over time, leading to variations in processing results and reduced yield.
Innovation Solution
A plasma processing method involving the adjustment of heat-transfer gas supply to maintain a constant pressure in the gap between the wafer and the sample stage, using a pressure control mechanism that accounts for initial and post-processing measurements to ensure a consistent heat transfer coefficient, thereby stabilizing the wafer surface temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heater and coolant flow channel are combined in a dielectric film structure to control wafer temperature, then temperature precision and speed responsiveness are improved, but individual differences in surface properties of the heat-transfer gas flow channel cause variations in wafer surface temperature distribution
Solution Approach 1:
The patent employs a feedback control mechanism where a temperature sensor detects the actual wafer surface temperature distribution, and this information is fed back to a controller that adjusts the heater power supply accordingly. This closed-loop control compensates for individual differences in heat-transfer gas flow channel surface properties, maintaining consistent temperature distribution across different sample stages and over time.
Solution Approach 2:
The system dynamically adjusts operational parameters (heater power, coolant flow rate) based on detected temperature conditions. By changing these parameters in response to measured temperature distribution, the system compensates for variations in heat-transfer gas flow channel properties, ensuring reliable and consistent wafer surface temperature control.
2Reliability
If the heat-transfer gas flow channel surface properties change over time due to plasma exposure, then processing consistency deteriorates, but re-calibration and adjustment are required to maintain temperature uniformity
Solution Approach 1:
The feedback control system continuously monitors wafer surface temperature and adjusts heater power in real-time, compensating for gradual changes in heat-transfer gas flow channel surface properties caused by plasma exposure. This eliminates the need for manual re-calibration during the service life of the sample stage.
Solution Approach 2:
The system performs self-adjustment through automated feedback control, where the temperature sensor and controller work together to maintain optimal temperature distribution without requiring external intervention or re-calibration, even as the heat-transfer gas flow channel surface properties change over time.
3Temperature
If heat-transfer gas is supplied to complement contact heat transfer, then temperature distribution uniformity is improved, but pressure control complexity increases to maintain consistent heat transfer coefficient
Solution Approach 1:
Pressure sensors monitor the heat-transfer gas pressure in the gap between the wafer and sample stage, and this information is fed back to a controller that adjusts the gas supply flow rate. This feedback control maintains consistent heat transfer coefficient despite variations in system conditions, simplifying the overall control strategy.
Solution Approach 2:
The patent uses pneumatic control of heat-transfer gas pressure and flow to achieve precise temperature distribution control. By utilizing gas pressure regulation mechanisms, the system maintains consistent heat transfer conditions without requiring complex mechanical or electrical control systems.
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 maintains a constant wafer surface temperature distribution, independent of individual sample stage variations and long-term plasma exposure changes, ensuring consistent processing results and improved yield.
Implementation Method 1
supplying a heat-transfer gas into a gap between the wafer and the top surface of the sample stage
Implementation Method 2
complement contact heat transfer between a back surface of the wafer and a wafer adsorption surface of the sample stage
Implementation Method 3
generating a plasma in a space above the sample stage inside the processing chamber and starting processing of the wafer
Implementation Method 4
supplying a process gas to the inside of a processing vessel decompressed down to a vacuum state to generate plasma
Implementation Method 5
a function of adsorbing and holding the wafer by electrostatic force
Implementation Method 6
disposing a film-like heater in a film arranged on a top surface of the sample stage
Data Source
AI summary
Provided is a plasma processing apparatus including a processing chamber which is disposed in a vacuum vessel and able to be decompressed, a sample stage on a top surface of which a wafer to be processed is mounted, an opening which is configured to supply a heat-transfer gas to a gap between the wafer and the top surface of the sample stage, a regulator which regulates a flow rate of the heat-transfer gas, and a controller which regulates an operation of the regulator based on a pressure of the gap detected using an amount of the heat-transfer gas leaking from the regulator to the processing chamber through the gap while the wafer is mounted on the sample stage and an amount of the heat-transfer gas supplied from the opening to the processing chamber while the wafer is not mounted on the sample stage.