Upper Electrode Temperature Control in Plasma Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma processing apparatuses face challenges in accurately controlling the temperature of the upper electrode, particularly when high-frequency power and DC voltage are applied, leading to undesirable temperature increases that affect processing quality.
Innovation Solution
A plasma processing apparatus with a temperature adjustment device that circulates a heating medium through the upper electrode, calculating the target temperature based on the levels of high-frequency power and DC voltage applied, using an arithmetic operation expression that includes terms for high-frequency power, DC voltage, and processing time to maintain the electrode at a precise temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-frequency power is applied to the upper electrode for plasma generation, then plasma is generated effectively, but the temperature of the upper electrode rises to an undesirably high level
Solution Approach 1:
The patent applies preliminary cooling action by circulating a cooling medium through the upper electrode before and during high-frequency power application. The cooling medium flow is established in advance to prevent temperature rise, and the cooling capacity is adjusted based on predicted heat generation from the high-frequency power level, thereby maintaining electrode temperature within desired ranges while enabling effective plasma generation.
2Manufacturing precision
If DC voltage is applied to the upper electrode for precision control of plasma potential and density, then plasma uniformity is improved, but the temperature of the upper electrode increases significantly
Solution Approach 1:
The patent implements feedback control by monitoring the upper electrode temperature and adjusting the cooling medium flow rate or temperature in response to detected temperature changes. When DC voltage is applied to achieve precision plasma control, the feedback system detects the resulting temperature increase and compensates by enhancing cooling, thereby maintaining both plasma uniformity and acceptable electrode temperature.
3Stability of the object's composition
If the upper electrode is designed with greater thermal capacity for stability, then temperature response to adjustment is slower, but temperature stability is improved
Solution Approach 1:
The patent applies dynamic cooling control where the cooling medium flow rate is continuously adjusted based on real-time temperature measurements and predicted heat generation from power sources. This dynamic adjustment allows the system to respond quickly to temperature changes when needed (overcoming the slow response inherent in high thermal capacity designs) while maintaining temperature stability during steady-state operation, effectively decoupling response speed from stability.
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 effectively inhibits temperature increases due to high-frequency power and DC voltage, ensuring accurate and consistent temperature control of the upper electrode during substrate processing, thereby improving processing quality and consistency.
Implementation Method 1
a temperature adjustment device that adjusts the temperature of the upper electrode by circulating a heating medium with the temperature thereof adjusted to a predetermined level through a flow passage formed in the upper electrode
Implementation Method 2
high-frequency power with individually selected specific frequencies is supplied to the susceptor and the upper electrode, thereby generating plasma with the processing gas in the space between the substrate and the upper electrode
Data Source
AI summary
Before a substrate is processed in a plasma processing apparatus that inhibits an increase in the temperature of an upper electrode attributable to DC voltage application as well as an increase in the upper electrode temperature attributable to high-frequency power application, a heating medium target temperature to be achieved by a heating medium in order to adjust the upper electrode temperature to a predetermined temperature setting is calculated based upon the levels of the high-frequency power to be applied to the upper electrode and a susceptor (lower electrode) and the DC voltage to be applied to the upper electrode. During the substrate processing, the heating medium, the temperature of which is controlled based upon the target temperature, circulates through a flow passage formed at the upper electrode so as to control the temperature of the upper electrode.