Upper Electrode Temperature Control via Dynamic Coolant Flow
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Solution Overview
Problem
Plasma processing apparatuses face challenges in rapidly and efficiently controlling the temperature of upper electrodes, which affects the etching and cleaning processes, leading to deposit accumulation and reduced process efficiency.
Innovation Solution
A temperature control method for upper electrodes in capacitively coupled plasma processing apparatuses, involving a chiller unit with a compressor, condenser, expansion valve, and flow dividing valve to manage coolant flow, allowing for both cooling and rapid heating of the upper electrode, along with the generation of a negative bias voltage to enhance etching and cleaning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the upper electrode is cooled continuously, then the temperature is maintained low, but the temperature cannot be increased rapidly when needed
Solution Approach 1:
The cooling system dynamically adjusts coolant flow based on process requirements. The flow rate is increased during cooling phases and decreased or stopped during heating phases, allowing the upper electrode temperature to be controlled rapidly in both directions. This dynamic control resolves the contradiction between maintaining low temperature and enabling rapid temperature increase.
Solution Approach 2:
The system changes the coolant flow rate parameter to control temperature. By adjusting the flow rate from high (for rapid cooling) to low or zero (allowing heating), the system achieves rapid temperature transitions. This parameter change enables the upper electrode to switch between cooling and heating states quickly.
2Productivity
If coolant flow rate is increased for rapid cooling, then cooling efficiency improves, but the system cannot provide rapid heating capability
Solution Approach 1:
The cooling system operates dynamically with variable flow rates. During high-efficiency cooling operations, the flow rate is maximized. During heating operations, the flow rate is reduced or stopped. This dynamic operation provides both rapid cooling capability and rapid heating capability, achieving temperature control flexibility while maintaining high cooling efficiency when needed.
Solution Approach 2:
The coolant flow is applied periodically rather than continuously. The system alternates between high-flow cooling periods and low-flow or no-flow heating periods. This periodic action allows the system to achieve both rapid cooling when required and rapid heating when required, providing versatility in temperature control.
3Object-generated harmful factors
If the upper electrode temperature is kept low during etching, then deposit accumulation is reduced, but cleaning process efficiency decreases
Solution Approach 1:
The temperature control operates periodically, maintaining low temperature during etching to reduce deposit accumulation, then rapidly increasing temperature during cleaning phases to enhance cleaning efficiency. This periodic temperature variation resolves the contradiction by optimizing temperature for each specific process stage.
Solution Approach 2:
The system preliminarily cools the upper electrode before and during etching to prevent excessive deposit accumulation. Then, it rapidly heats the electrode during cleaning phases to improve cleaning efficiency. This preliminary cooling action and subsequent heating action address both requirements sequentially.
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 method enables efficient cooling and rapid heating of the upper electrode, reducing deposit accumulation and improving the etching and cleaning processes by increasing the amount of chemical species capable of etching deposits, thereby enhancing the overall efficiency and reducing the risk of deposits adhering to the electrode.
Implementation Method 1
As the coolant is vaporized within the path of the upper electrode, the upper electrode is cooled
Implementation Method 2
A compressor, a condenser and an expansion valve are connected in sequence between the outlet and the inlet of the path
Data Source
AI summary
A temperature control method includes cooling an upper electrode and increasing a temperature of the upper electrode. A path having an inlet and an outlet is formed within the upper electrode. The upper electrode constitutes an evaporator. A compressor, a condenser and an expansion valve are connected in sequence between the outlet and the inlet of the path. A flow dividing valve is connected between an output of the compressor and the inlet to bypass the condenser and the expansion valve. In the cooling of the upper electrode, a coolant is supplied into the path via the compressor, the condenser and the expansion valve. In the increasing of the temperature of the upper electrode, the flow dividing valve is opened and the upper electrode is heated.