Segmented Coil Magnetic Field Control for Uniform Plasma Processing
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in achieving uniform plasma density distribution within a chamber, leading to non-uniform etching and deposition processes in semiconductor manufacturing.
Innovation Solution
A plasma processing apparatus with a chamber that includes a donut-shaped core and multiple coils to generate a magnetic field, where a current supply device and controller adjust the magnetic field intensity to optimize plasma density uniformity, using a plasma measurement device to calculate plasma density based on the plasma sheath region voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a magnetic field is applied to a plasma region to improve plasma characteristics, then plasma density and uniformity are improved, but the device complexity increases due to additional magnetic field generation components
Solution Approach 1:
The magnetic field generation system is segmented into multiple independent coils (first upper outer coil, second upper outer coil, first lower outer coil, second lower outer coil) that can be controlled separately. Each coil contributes to different regions of the plasma chamber, allowing localized adjustment of magnetic field strength to achieve uniform plasma density distribution across the wafer surface.
Solution Approach 2:
Different coils are positioned to create locally optimized magnetic field distributions. The upper and lower outer coils are arranged to target specific radial zones of the plasma chamber, enabling independent control of plasma characteristics in different spatial regions. This local quality approach allows precise adjustment of plasma density uniformity without requiring a complete redesign of the entire system.
2Manufacturing precision
If multiple coils are used to generate magnetic field for plasma uniformity, then plasma density distribution is improved, but the control system complexity increases
Solution Approach 1:
The control system dynamically adjusts the current supplied to each coil based on real-time plasma density measurements. The controller receives feedback from plasma density sensors and modulates the coil currents accordingly, enabling adaptive control that maintains optimal plasma uniformity across different operating conditions without requiring complex manual calibration.
Solution Approach 2:
A feedback control loop is implemented where plasma density is measured by a dedicated measurement device and fed back to the controller. The controller processes this information and adjusts the current to each coil to compensate for deviations from the desired plasma density distribution, achieving self-correcting control that simplifies the overall system operation despite the presence of multiple coils.
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 apparatus achieves improved plasma uniformity and etching consistency across the wafer surface by finely controlling the magnetic field distribution, enhancing the reliability of semiconductor processes.
Implementation Method 1
a core located on the chamber and configured to form a magnetic field in the chamber, and a plurality of coils located adjacent to the core
Implementation Method 2
a magnetic field may limit plasma in a chamber to reduce damage to an inner wall of the chamber due to the plasma. Also, a magnetic field may help to generate and sustain plasma by activating movement of electrons, thereby increasing a plasma density
Implementation Method 3
a plasma measurement device configured to calculate a plasma density by using a voltage of a plasma sheath region generated in the chamber
Data Source
AI summary
Provided is a plasma processing apparatus. The plasma processing apparatus includes a chamber configured to isolate a plasma region where plasma is formed from an outside, a core located on the chamber and configured to form a magnetic field in the chamber, and a plurality of coils located adjacent to the core, wherein the core includes a first core having a donut shape, and the plurality of coils include first and second upper outer coils located on a top surface of the first core.