Substrate Mounting Table With Protrusion-Defined Cooling Regions
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Solution Overview
Problem
The nonuniformity in substrate temperature during plasma processing due to varying heat transfer characteristics around power feed lines in electrostatic chucks leads to inconsistent etching processes, as the insulating material surrounding the power feed lines has low thermal conductivity, resulting in reduced heat dissipation and increased surface temperatures near these areas.
Innovation Solution
A substrate mounting table with a protrusion portion to divide the substrate surface into regions, incorporating inlet and discharge ports for cooling gases, and a controller to manage gas pressures or flow rates, ensuring uniform heat dissipation by varying the thermal conductivity between the power feed line and other areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating material surrounds the power feed line, then electrical insulation is improved, but thermal conductivity deteriorates causing nonuniform substrate temperature
Solution Approach 1:
The patent applies local quality by providing a thermal conductivity-enhancing material specifically in the vicinity of the power feed line, while other portions of the mounting table maintain their original thermal properties. This localized modification addresses the heat transfer issue only where the insulating material causes problems, without changing the entire mounting table structure.
Solution Approach 2:
The patent uses composite materials by combining the insulating material (which provides electrical insulation) with a thermal conductivity-enhancing material (such as thermally conductive adhesive or filler). This composite structure maintains the necessary electrical insulation while improving heat transfer in the critical area around the power feed line.
2Force
If high voltage DC power is applied to the electrode plate, then substrate holding force is improved, but heat generation increases causing temperature rise near power feed line
Solution Approach 1:
The patent introduces a thermal conductivity-enhancing material as an intermediary between the insulating material and the mounting table. This intermediary material facilitates heat transfer from the high-voltage region to the coolant path, acting as a thermal bridge that allows heat dissipation without compromising electrical insulation.
Solution Approach 2:
The patent utilizes the existing coolant path (fluid-based thermal management system) more effectively by improving heat transfer to the coolant through the thermal conductivity-enhancing material. This allows the hydraulic/ pneumatic cooling system to remove excess heat generated by the high voltage application.
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 maintains a uniform substrate temperature by controlling cooling gas pressures and flow rates, reducing temperature variations near power feed lines and improving the quality of plasma processing by ensuring consistent heat transfer across the substrate.
Implementation Method 1
A high voltage DC power is applied to the electrode plate to adsorptively hold the substrate by a Coulomb force or a Johnson-Rahbek force
Implementation Method 2
A high voltage DC power is applied to the electrode plate to adsorptively hold the substrate by a Coulomb force or a Johnson-Rahbek force
Implementation Method 3
a heat transfer gas such as He gas is introduced into a gap between the mounting table and a backside of the wafer to facilitate cooling of the wafer
Data Source
AI summary
A substrate mounting table is disposed in a processing chamber for performing a plasma process on a substrate and includes at least one power feed part formed of an insulating material surrounding a power feed line and a cooling medium path. The substrate mounting table further includes a protrusion portion for dividing a space formed on a substrate mounting surface of the mounting table into regions, inlet ports through which cooling gases are introduced into the regions divided by the protrusion portion, and a controller for controlling pressures or flow rates of the cooling gases.