Plasma Processing Apparatus Electromagnet for Vertical Etching
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Solution Overview
Problem
In semiconductor wafer etching processes using capacitively coupled plasma etching apparatuses, the formation of contact holes with high aspect ratios often results in tilting due to uneven ion sheath and bulk plasma interfaces, leading to reduced yield and efficiency.
Innovation Solution
A plasma processing apparatus with an electromagnet featuring annular coils around the central axis is used to control plasma density distribution, selectively energizing coils to flatten the ion sheath interface and ensure vertical ion incidence, thereby suppressing tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional capacitively coupled plasma etching is used for high aspect ratio contact holes, then etching can be performed, but tilting occurs due to uneven ion sheath interface
Solution Approach 1:
The magnet system is divided into multiple independent magnets arranged in an annular array, allowing selective energization of individual magnets to control plasma density distribution in specific radial zones, thereby flattening the ion sheath interface and preventing tilting
Solution Approach 2:
Different regions of the processing container are assigned different plasma density characteristics by selectively energizing specific magnets, creating locally optimized conditions that maintain vertical ion incidence across the entire wafer surface
2Productivity
If plasma density is increased to improve etching rate, then productivity increases, but ion sheath interface unevenness worsens causing more tilting
Solution Approach 1:
The system dynamically adjusts plasma density distribution by controlling the energization state of individual magnets, allowing high overall plasma density for fast etching while maintaining local uniformity to prevent tilting
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 effectively reduces tilting, enhances production efficiency, and lowers production costs by maintaining uniform plasma density and ion incidence across the wafer surface.
Implementation Method 1
an electromagnet having one or more annular coils around a central axis
Implementation Method 2
plasma is generated by a high frequency discharge between both electrodes
Implementation Method 3
a high frequency power is applied between both electrodes. Then, plasma is generated by a high frequency discharge between both electrodes
Implementation Method 4
an electromagnet having one or more annular coils around a central axis
Data Source
AI summary
Disclosed is a plasma processing apparatus for performing a processing on a processing target substrate by applying of plasma of a processing gas to the processing target substrate. The plasma processing apparatus includes: a processing container configured to removably accommodate the processing target substrate; a lower electrode provided in the processing container to place the processing target substrate thereon; an upper electrode provided in the processing container to face the lower electrode; a high frequency power source configured to apply a high frequency power between the upper electrode and the lower electrode; and an electromagnet having one or more annular coils around a central axis that passes through a center of the lower electrode vertically in an upper portion or at an upper side of the processing container.