Electromagnet Array Control for Uniform Plasma Distribution
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Solution Overview
Problem
Existing magnetic field generation devices in plasma etching processes struggle to control plasma distribution uniformly, particularly in the radial and azimuth directions, due to limitations in magnetic field profile control and hysteresis characteristics of magnetic cores, leading to non-uniform plasma density and erosion profiles.
Innovation Solution
A magnetic field generation device comprising an array of electromagnets with a current controller and magnetic field controller, capable of generating a time-varying rotating magnetic field by controlling pulse duty cycles and current waveforms to achieve desired magnetic field distributions, thereby enhancing radial and azimuthal uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a time-varying rotating magnetic field generation device is used to control plasma distribution, then plasma uniformity is improved, but device complexity increases due to multiple electromagnets and control systems
Solution Approach 1:
The magnetic field generation device is divided into multiple independent electromagnets arranged in an array, with each electromagnet controlled separately by individual current waveforms. This segmentation allows precise spatial control of the magnetic field to achieve uniform plasma distribution while managing complexity through modular design
Solution Approach 2:
The device employs time-varying current waveforms with adjustable pulse duty cycles to dynamically control the magnetic field strength and distribution. The magnetic field controller calculates and adjusts current parameters in real-time to maintain optimal plasma uniformity under varying process conditions
Solution Approach 3:
The system controls plasma distribution by varying multiple parameters including current amplitude, pulse duty cycle, and phase relationships between different electromagnets. The magnetic field controller adjusts these parameters to generate the desired time-varying rotating magnetic field profile
2Measurement precision
If pulse duty cycle control is applied to current waveforms, then magnetic field distribution precision is improved, but control system complexity increases
Solution Approach 1:
The system incorporates magnetic field sensors that measure the actual magnetic field distribution and provide feedback to the magnetic field controller. The controller uses this feedback information to adjust current waveforms and pulse duty cycles, achieving precise magnetic field control through closed-loop regulation
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with electronic control of pulse duty cycles. The current controller digitally adjusts the width of current pulses to precisely control magnetic field strength, eliminating the need for mechanical variable resistors or physical reconfiguration
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
The device enables precise control of plasma distribution, ensuring uniformity and accuracy in plasma processes by generating various magnetic field profiles, improving plasma density control and reducing non-uniformity in etching facilities.
Implementation Method 1
Each of the plurality of coils is configured to generate a time-varying rotating magnetic field in response to an applied current waveform
Implementation Method 2
an array of electromagnets including a plurality of electromagnets
Data Source
AI summary
Example embodiments are directed a magnetic field generation device including an array of electromagnets including a plurality of electromagnets, and a current controller configured to generate a plurality of current waveforms and to apply each current waveform to a respective one of the plurality of electromagnets. The current controller is further configured to control a pulse duty cycle of each of the plurality of current waveforms. The magnetic field generation device also includes a magnetic field controller configured to calculate each of the plurality of current waveforms to be provided to the respective one of the plurality of electromagnets to generate a desired magnetic field distribution. The plurality of electromagnets include a central electromagnet, and peripheral electromagnets having symmetry in an azimuth direction and arranged about the central electromagnet. Each electromagnet includes a magnetic core and a coil, and a yoke magnetically couples the electromagnets to each other.