Segmented RF Coil Layout for Local Plasma Distribution in Etching
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Solution Overview
Problem
Existing etching processes face limitations in adjusting plasma distribution in partial areas due to the concentric circle configuration of RF coils, which restricts etch uniformity and product yield.
Innovation Solution
Employing a circular RF coil composed of four arcs connected to a cross support, with different currents applied to each arc to generate distinct magnetic fields, allowing for adjustable plasma distribution by varying current magnitudes and directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a complete concentric circle RF coil is used, then the magnetic field distribution can be adjusted by changing the current, but only concentric circle mode adjustment is achieved and partial area adjustment function cannot be realized
Solution Approach 1:
The RF coil is divided into four separate arc segments (first arc, second arc, third arc, fourth arc) instead of using a complete concentric circle. Each arc segment can be independently controlled with different currents, enabling partial area plasma distribution adjustment while maintaining a relatively simple overall circular structure.
2Manufacturing precision
If a symmetrical cavity structure is adopted, then etch uniformity can be improved, but absolute symmetry cannot be achieved causing uneven plasma distribution
Solution Approach 1:
Different current magnitudes are applied to different arc segments (first arc, second arc, third arc, fourth arc) to create localized magnetic field variations. This enables independent control of plasma distribution in different areas of the cavity, allowing etch uniformity improvement through precise local adjustment rather than relying on perfect symmetry.
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
Enhances etch uniformity and expands the process window, improving product yield by enabling precise control over plasma concentration in specific areas.
Implementation Method 1
RF coils of the existing etching cavity are all complete concentric circles, and the distribution of induced magnetic fields is changed by adjusting a current flowing through the coil
Data Source
AI summary
The present application provides a method for improving plasma distribution in etching, the RF coil is a circular coil composed of four arcs, and the four arcs are sequentially defined as first to fourth arcs; providing a cross support, wherein heads and tails of the first to fourth arcs are separately connected to the cross support; respectively applying different currents to the first to fourth arcs, which are sequentially first to fourth currents, so that different magnetic fields are formed respectively in areas enclosed by the first to fourth arcs and the cross support connected thereto, wherein the magnetic fields corresponding to the first to fourth currents are sequentially first to fourth magnetic fields; and adjusting the magnitudes of the first to fourth currents to change the first to fourth magnetic fields, thereby changing plasma distribution in the different areas.