Wafer Placement Table RF Wiring for Heat and Plasma Control
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Solution Overview
Problem
Existing wafer placement tables with constant-width electroconductive lines experience significant temperature differences and inefficient plasma generation due to excessive heat generation and plasma coupling.
Innovation Solution
A wafer placement table with a connection circuit formed of electroconductive wires in a mesh-patterned or radial form, where the wire width broadens from the second RF electrode to the second RF terminal, reducing heat generation and plasma coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If constant-width electroconductive lines are used in the connection circuit, then the structure is simple and easy to manufacture, but temperature difference within the wafer placement surface becomes great and plasma generation efficiency is poor
Solution Approach 1:
The electroconductive wires in the connection circuit are designed with varying widths rather than constant width. Specifically, the wire width is narrower at the second RF electrode side and broader at the second RF terminal side. This local variation in geometric properties optimizes heat distribution and reduces temperature differences across the wafer placement surface while maintaining manufacturing feasibility.
2Device complexity
If constant-width electroconductive lines are used in the connection circuit, then the structure is simple, but plasma coupling between the first RF electrode and the connection circuit increases, reducing plasma generation efficiency
Solution Approach 1:
The connection circuit employs electroconductive wires with non-uniform width distribution. The wires are narrower near the second RF electrode and broader toward the second RF terminal. This local quality variation reduces the overlap area between the first RF electrode and the connection circuit, thereby minimizing parasitic plasma coupling and improving plasma generation efficiency above the wafer placement surface.
3Productivity
If narrow-width electroconductive wires are used in the connection circuit, then plasma coupling is reduced, but heat generation of the connection circuit increases
Solution Approach 1:
The geometric parameter of the electroconductive wires (width) is varied along their length. The wire width transitions from narrow at the second RF electrode side to broad at the second RF terminal side. This parameter change allows the connection circuit to simultaneously reduce plasma coupling (via narrower sections) and minimize heat generation (via broader sections that reduce current density), achieving both objectives.
4Loss of energy
If broad-width electroconductive wires are used in the connection circuit, then heat generation is reduced, but plasma coupling between the first RF electrode and the connection circuit increases
Solution Approach 1:
The electroconductive wires exhibit spatially varying width characteristics. The narrower portions near the second RF electrode minimize overlap with the first RF electrode, reducing parasitic plasma coupling. The broader portions toward the second RF terminal reduce current density and heat generation. This local differentiation resolves the contradiction between reducing heat generation and minimizing plasma coupling.
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 design reduces temperature differences and enhances plasma generation efficiency by suppressing heat generation and minimizing plasma coupling, allowing for better temperature control and plasma formation on the wafer surface.
Implementation Method 1
a connection circuit that connects the second RF terminal and the second RF electrode, wherein the connection circuit is formed of electroconductive wires
Implementation Method 2
heat generation of the electroconductive wires forming the connection circuit can be suppressed as compared to a case in which the width of the electroconductive wires is constant at a narrow value
Implementation Method 3
plasma can be generated above the wafer placement surface with good efficiency
Implementation Method 4
plasma coupling between the first RF electrode and the connection circuit is reduced
Data Source
AI summary
A wafer placement table includes a ceramic plate that has a wafer placement surface, a first RF electrode that is circular and that is embedded in the ceramic plate, a first RF terminal that is electrically connected to the first RF electrode, a second RF electrode that is annular and that is positioned at an outer side of the first RF electrode in plan view, and that is embedded in the ceramic plate at a different depth from the first RF electrode, a second RF terminal that is electrically connected to the second RF electrode and a connection circuit that connects the second RF terminal and the second RF electrode. The connection circuit is formed of electroconductive wires that are in a mesh-patterned form or in a radial form. A width of the electroconductive wires becomes broader from the second RF electrode toward the second RF terminal.