Ceiling Electrode Plate Heat Transfer Sheet for Plasma Etching
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Solution Overview
Problem
The existing substrate processing apparatuses face challenges in uniformly maintaining the temperature of the ceiling electrode plate during plasma etching processes, leading to instability in etching rates due to low heat transfer efficiency in vacuum environments and time lags in temperature control.
Innovation Solution
A ceiling electrode plate is supported by an electrode support with a temperature adjusting mechanism, featuring a heat-transfer sheet between the ceiling electrode plate and the cooling plate, with gas holes and a specific thickness, and thermal conductivity within a certain range, to enhance heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cooling plate is used to transfer heat from the ceiling electrode plate in a vacuum environment, then the structure is simple and easy to manufacture, but heat transfer efficiency is low and temperature control has time lag
Solution Approach 1:
A heat transfer sheet is introduced as an intermediary material between the ceiling electrode plate and the cooling plate. This sheet enhances thermal contact and improves heat transfer efficiency without complicating the overall structure. The sheet acts as a mediator that bridges the thermal gap in the vacuum environment, allowing effective temperature control while maintaining structural simplicity.
Solution Approach 2:
The thermal contact parameters are changed by introducing the heat transfer sheet with specific thermal conductivity properties. This parameter change enables more efficient heat transfer from the ceiling electrode plate to the cooling plate, reducing temperature fluctuations and eliminating time lag in temperature control while keeping the structural design simple.
2Device complexity
If the ceiling electrode plate temperature is allowed to fluctuate with plasma heat, then the structure remains simple, but etching rate uniformity across multiple wafers deteriorates
Solution Approach 1:
The heat transfer sheet serves as a thermal intermediary that connects the ceiling electrode plate to the cooling plate, enabling active temperature control. This mediator allows the system to maintain simple structural design while achieving precise temperature stabilization, which is critical for uniform etching rates across multiple wafers processed in the same lot.
Solution Approach 2:
By changing the thermal management parameters through the introduction of the heat transfer sheet, the system achieves stable temperature control of the ceiling electrode plate. This parameter change ensures that plasma heat does not cause temperature fluctuations that would affect radical distribution and etching uniformity, thereby improving manufacturing precision without increasing device complexity.
3Device complexity
If heat transfer efficiency between the ceiling electrode plate and cooling plate is low, then the structure is simple, but temperature stabilization time increases and process property stability decreases
Solution Approach 1:
The heat transfer sheet acts as a thermal intermediary that significantly improves heat transfer efficiency between the ceiling electrode plate and cooling plate. This intermediary material reduces thermal resistance, allowing the system to stabilize temperatures quickly without adding structural complexity. The simple sheet design eliminates time lag in temperature control while maintaining ease of manufacture.
Solution Approach 2:
The thermal contact parameters are optimized by introducing the heat transfer sheet with appropriate thermal conductivity. This parameter change accelerates heat transfer from the ceiling electrode plate to the cooling plate, reducing temperature stabilization time and improving process property stability without complicating the heat transfer structure.
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 stabilizes the temperature of the ceiling electrode plate from the onset of plasma generation, ensuring uniform etching processes across multiple wafers and preventing thermal expansion, while maintaining effective heat distribution and preventing particle generation.
Implementation Method 1
a heat-transfer sheet is provided in a contact surface of the ceiling electrode plate between the ceiling electrode plate and the cooling plate
Implementation Method 2
the ceiling electrode plate is cooled via the cooling plate that serves as a heat diffusion plate, thereby adjusting the temperature of the ceiling electrode plate
Implementation Method 3
heat generated from plasma is applied to the ceiling electrode plate provided over the substrate holding stage
Data Source
AI summary
In a plasma processing apparatus, a ceiling electrode plate provided to face a substrate holding stage via a process space contacts and is supported by an electrode support by interposing a cooling plate, and a heat-transfer sheet is provided in a contact surface between the ceiling electrode plate and the cooling plate. The heat-transfer sheet has thermal conductivity of 0.5 to 2.0 W/m·K. The heat-transfer sheet is provided of a heat-resistant adhesive agent or a rubber including silicon, or the heat-transfer sheet is formed of a ceramic filler including oxide, nitride, or carbide. The ceramic filler of 25 to 60 volume % is contained in the heat-resistant adhesive agent or the rubber. A thickness of the heat-transfer sheet is in a range between 30 and 80 μm, and the heat-transfer sheet is not provided in a predetermined area around gas holes of the ceiling electrode plate.