Upper Electrode Temperature Compensation in Plasma Processing
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Solution Overview
Problem
In parallel flat-panel type plasma processing apparatuses, the temperature of the upper electrode increases due to exposure to plasma, leading to decreased etching speed and processing uniformity issues across substrates, as the environment changes during operation, affecting the processing results and throughput.
Innovation Solution
A temperature adjusting mechanism is implemented to compensate for the temperature increase of the upper electrode by adjusting the set temperature based on the elapsed time or number of processed substrates, using a compensation value table to control the heater power and cooling medium flow, thereby maintaining a consistent temperature and reducing variations in processing results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper electrode is exposed to plasma for processing, then the plasma processing function is achieved, but the temperature of the upper electrode increases leading to decreased etching speed and processing uniformity
Solution Approach 1:
The patent applies preliminary action by pre-setting a temperature compensation value before plasma processing begins. The control unit stores compensation values in advance that correspond to different elapsed times, and automatically selects and applies the appropriate compensation value during processing. This prevents temperature-induced variations before they occur, rather than attempting to correct them after the upper electrode temperature has changed.
Solution Approach 2:
The patent implements feedback by continuously monitoring the elapsed time during plasma processing and using this information to dynamically adjust the temperature compensation value. The control unit calculates the elapsed time from the start of plasma generation and selects compensation values from stored data, creating a closed-loop system that automatically compensates for temperature drift based on real-time processing conditions.
2Speed
If the set temperature of the upper electrode is maintained constant, then the initial processing speed is maintained, but the processing environment changes as the apparatus operates leading to non-constant processing state
Solution Approach 1:
The patent applies dynamics by transitioning from a static temperature set value to a dynamic compensation system. Instead of maintaining a constant temperature set value that becomes invalid as processing progresses, the system dynamically adjusts the compensation value based on elapsed time. This allows the temperature control to adapt to changing processing conditions while maintaining consistent etching speed and uniformity throughout the entire processing run.
3Manufacturing precision
If no temperature compensation is applied, then the apparatus operation is simple, but the processing result varies between substrates as the upper electrode temperature increases over time
Solution Approach 1:
The patent implements self-service by enabling the system to automatically compensate for temperature drift without requiring external intervention or complex real-time temperature measurement. The control unit uses readily available elapsed time information to select appropriate compensation values from pre-stored data, allowing the system to self-correct temperature-induced variations. This approach maintains high manufacturing precision while avoiding the complexity of installing temperature sensors in the high-frequency environment.
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 solution effectively suppresses the increase in upper electrode temperature, stabilizes etching speed, and ensures consistent processing results across substrates by compensating the set temperature of the upper electrode, reducing variations caused by its consumption over time.
Implementation Method 1
high-frequency power is applied between both the electrodes to convert a processing gas into plasma
Implementation Method 2
the temperature of a substrate is determined by heat dissipation to the placing table, heat absorption from plasma, and radiation heat from the upper electrode
Implementation Method 3
a value of power supplied to a heater for heating the upper electrodes
Implementation Method 4
heat dissipation to the placing table
Implementation Method 5
controlling the flow rate of a cooling medium
Data Source
AI summary
Provided is a parallel flat-panel type plasma processing apparatus which includes a recipe storing unit storing a processing recipe for performing a plasma processing, a compensation setting unit setting an accumulation time of the plasma processing or the number of processed substrates after starting using a new second electrode and the compensation value of the set temperature of the second electrode in an input screen, and a storage unit storing the compensated set value. The plasma processing apparatus is further equipped with a program for controlling a temperature adjusting mechanism based on a set temperature after compensation by adding a set temperature of an upper electrode written in the processing recipe to the compensation value stored within the storage unit. As a result, the non-uniformity in the plasma processing between the substrates caused by the change of processing atmosphere is suppressed.