Plasma Coil Spacing Near Ground Points for Uniform Substrate Processing
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Solution Overview
Problem
The substrate processing apparatus experiences deterioration in in-plane uniformity of substrate processing due to biased plasma density in the in-plane direction, particularly near the grounding points on the coil.
Innovation Solution
The apparatus is configured with a process container where a process gas is plasma-excited, and a coil spirally wound along the outer periphery of the process container, with a longer coil separation distance at the first grounding point compared to other sections, to reduce plasma density bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the coil is uniformly wound around the process container, then the coil structure is simple and easy to manufacture, but the plasma density becomes biased near the grounding points, deteriorating the in-plane uniformity of substrate processing
Solution Approach 1:
The coil winding pitch is made non-uniform with different pitch values in different axial sections. Specifically, the winding pitch varies along the axial direction, creating local differences in coil density that compensate for the plasma density bias caused by grounding points, thereby improving overall in-plane uniformity without requiring complete structural redesign
Solution Approach 2:
The coil winding structure transitions from symmetric uniform winding to asymmetric non-uniform winding. The winding pitch is deliberately made asymmetric with respect to the axial position, creating intentional structural asymmetry that counteracts the symmetric plasma bias pattern generated by grounding points
2Manufacturing precision
If the coil separation distance is increased at the first grounding point, then the plasma density bias is reduced, but the coil structure becomes more complex
Solution Approach 1:
The coil separation distance is locally adjusted only at specific axial sections where grounding points are located, rather than uniformly throughout the entire coil. This localized modification targets the plasma density bias problem at its source while minimizing overall structural complexity
Solution Approach 2:
The coil separation distance parameter is varied along the axial direction, transitioning from a constant value to a position-dependent value. This parameter change allows optimization of plasma density distribution by adjusting the magnetic field intensity at different axial positions
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 configuration improves the in-plane uniformity of substrate processing by reducing plasma density bias, thereby enhancing the uniformity of film formation on the substrate.
Implementation Method 1
a process container in which a process gas is plasma-excited by supplying high frequency power to a coil
Implementation Method 2
the coil being configured to supply high frequency power
Data Source
AI summary
There is included a process container; a gas supply system; and a coil provided with a section between a first grounding point and a second grounding point of the coil so as to be spirally wound a plurality of times along an outer periphery of the process container, wherein the coil is configured so that a coil separation distance, which is a distance from an inner periphery of the coil to an inner periphery of the process container, in a partial section of a first winding section, which is a section where the coil winds once along the outer periphery of the process container in a direction from the first grounding point toward the second grounding point, is longer than a coil separation distance in another partial section of the first winding section continuous with the partial section of the first winding section.