Plasma Chamber Heater Temperature Control via Frequency Segmentation
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Solution Overview
Problem
The existing plasma processing apparatuses face challenges in accurately controlling the temperature of the heater in the electrostatic chuck, which affects the precision of plasma processing due to noise interference from pulsed radio frequency power and negative voltage applications.
Innovation Solution
A plasma processing apparatus with a controller system that differentiates between the frequencies of pulsed radio frequency power supply and negative voltage application, and heater power control, using resistance values from sampled current and voltage to determine and maintain accurate temperature, thereby reducing noise interference and improving temperature control accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pulsed radio frequency power is supplied to the lower electrode and negative voltage is applied to the edge ring, then plasma processing is performed and sheath position is corrected, but noise interferes with heater temperature control accuracy
Solution Approach 1:
The controller segments the control frequencies into three distinct groups: a first frequency for pulsed radio frequency power supply, a second frequency for negative voltage application, and a third frequency for heater power control. This frequency segmentation isolates the heater control signals from noise generated by plasma processing operations, enabling accurate temperature control while maintaining effective plasma treatment.
Solution Approach 2:
The controller acts as an intermediary that coordinates multiple power supplies operating at different frequencies. By using frequency division as the mediating mechanism, the system allows simultaneous operation of plasma generation (radio frequency power), sheath correction (negative voltage), and temperature control (heater power) without mutual interference, resolving the contradiction between processing effectiveness and measurement accuracy.
2Adaptability or versatility
If multiple power supplies operate simultaneously for plasma processing and sheath correction, then processing functionality is improved, but noise from these operations interferes with temperature measurement
Solution Approach 1:
The system segments the operational frequencies of multiple power supplies into distinct bands. The controller assigns specific frequencies to each power supply function, ensuring that plasma generation, sheath correction, and heater control operate independently in the frequency domain. This prevents noise from plasma processing and sheath correction from contaminating temperature measurements while maintaining all processing functionalities.
Solution Approach 2:
The controller dynamically adjusts operational parameters, specifically frequency assignment, for each power supply based on its function. By changing the frequency parameter rather than operating all supplies at the same frequency, the system eliminates noise interference while preserving the versatility and effectiveness of multiple simultaneous processing operations.
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 solution enhances the accuracy of heater temperature control by minimizing noise influence, ensuring precise plasma processing conditions.
Implementation Method 1
at least one heater that is a resistance heating element disposed in the electrostatic chuck
Implementation Method 2
A radio frequency power is supplied from the radio frequency power supply to the lower electrode in order to perform the plasma processing
Implementation Method 3
The substrate support includes a lower electrode, an electrostatic chuck disposed on the lower electrode
Data Source
AI summary
A plasma processing apparatus includes a chamber; a substrate support having a lower electrode, an electrostatic chuck, and a heater; a radio frequency power supply; a DC power supply; a first controller; and a second controller. The first controller controls the radio frequency power supply to supply a pulsed radio frequency power to the lower electrode periodically with a cycle defined by a first frequency, and controls the DC power supply to apply a pulsed negative voltage to the edge ring periodically with the cycle. The second controller includes a heater controller that controls the power by obtaining a resistance value of the heater from sample values of a current and a voltage supplied to the heater. The first frequency is different from a second frequency that is a sampling frequency of the sample value of the current and the sample value of the voltage in the second controller.