Electrostatic Chuck Temperature Control With Adsorptive Sheets
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in efficiently diffusing heat from substrates and edge rings due to direct exposure to plasma, leading to temperature rise and potential issues with heat transfer and plasma uniformity.
Innovation Solution
The apparatus incorporates adsorptive sheets with temperature-dependent adhesive strength between the substrate and edge ring, and an electrostatic chuck system to control temperature and adhesive force, enhancing heat conductivity and plasma uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If direct contact between substrate and pedestal is used for heat transfer, then heat diffusion efficiency is improved, but substrate and edge ring temperature rise causing plasma uniformity issues
Solution Approach 1:
An adsorptive sheet is introduced as an intermediary layer between the substrate/edge ring and the electrostatic chuck. This sheet enables effective heat transfer from the substrate and edge ring to the cooled pedestal while preventing excessive temperature rise. The adsorptive sheet has thermal conductivity properties that facilitate heat diffusion from the plasma-exposed components to the temperature-controlled pedestal surface.
2Loss of energy
If adsorptive sheet with temperature-dependent adhesive strength is used, then heat transfer is improved, but substrate and ring replacement becomes difficult
Solution Approach 1:
The adsorptive sheet employs temperature-dependent adhesive strength that dynamically changes with temperature. At lower temperatures (during replacement operations), the adhesive strength decreases, allowing easy removal of substrates and edge rings. At higher temperatures (during plasma processing), the adhesive strength increases, ensuring stable fixation and effective heat transfer. This dynamic property resolves the contradiction between secure mounting and easy replacement.
3Stability of the object's composition
If higher adhesive strength is used to secure substrate and edge ring, then positioning stability is improved, but heat transfer efficiency decreases
Solution Approach 1:
The adhesive strength parameter of the adsorptive sheet is changed based on temperature conditions. During plasma processing, the elevated temperature increases adhesive strength to ensure stable positioning of the substrate and edge ring. During replacement operations, the lower temperature decreases adhesive strength to facilitate easy removal. This parameter change with temperature resolves the contradiction between stable positioning and heat transfer efficiency.
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
Improves heat diffusion and reduces the risk of helium gas leakage and particle generation, while maintaining in-plane temperature uniformity and facilitating easy substrate and ring replacement.
Implementation Method 1
an adsorptive sheet disposed at least one of between the substrate placing portion and the substrate placed on the substrate placing portion, or between the edge ring placing portion and the edge ring placed on the edge ring placing portion, and configured to change in adhesive strength by changing temperature
Implementation Method 2
a temperature adjuster configured to circulate the heat transfer medium through the flow path and to regulate a temperature of the heat transfer medium
Implementation Method 3
a first electrostatic electrode layer configured to be disposed in the substrate placing portion; a second electrostatic electrode layer configured to be disposed in the edge ring placing portion; a first power supply configured to be electrically connected to the first electrostatic electrode layer; a second power supply configured to be electrically connected to the second electrostatic electrode layer
Data Source
AI summary
A pedestal is disposed in a plasma processing chamber and has a flow path inside for a heat transfer medium. A temperature adjuster circulates the heat transfer medium through the flow path and regulates the temperature of the heat transfer medium. An electrostatic chuck on an upper surface of the pedestal has a substrate placing portion and an edge ring placing portion that surrounds a substrate, a first electrostatic electrode layer is disposed on the substrate placing portion and a second electrostatic electrode layer is disposed on the edge ring placing portion. An adsorptive sheet is disposed at least one of between the substrate placing portion and the substrate or between the edge ring placing portion and the edge ring, and changes in adhesive strength by changing temperature.