Magnetic Plasma Module for Uniform Wafer Etch Density Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma processing apparatuses struggle to uniformly control plasma density across the wafer surface, particularly in the middle region, due to misaligned magnetic field directions from separate magnetic field generating units, leading to non-uniform etching.
Innovation Solution
A plasma processing apparatus utilizing a combination of a permanent magnet and an electromagnet, positioned vertically above the reaction chamber, with parallel magnetic fields to adjust and control plasma density, and a signal determining unit to manage power input to the electromagnet based on coercive force differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate magnetic field generating units are provided on different walls of the vacuum container, then magnetic field lines can be formed throughout the vacuum chamber, but the magnetic field direction changes completely and plasma density control in the middle region cannot be performed delicately
Solution Approach 1:
The patent combines a permanent magnet and an electromagnet into a single magnetic field generating unit. This merging allows both units to be positioned at the same location, generating magnetic fields in the same direction that can be finely adjusted by controlling the electromagnet's field strength to reinforce or cancel the permanent magnet's field, thereby achieving delicate plasma density control in the middle region without the directional conflicts of separate units on different walls
Solution Approach 2:
The patent applies local quality by concentrating the magnetic field generating capability in a specific location (one wall rather than distributed on multiple walls) and using the combination of permanent magnet and electromagnet to create locally optimized magnetic field conditions. This allows precise control of plasma density in the middle region by adjusting the magnetic field strength at this specific position, rather than relying on distributed magnetic field generation that cannot provide localized control
2Manufacturing precision
If magnetic field units are positioned at different locations, then magnetic fields can be formed throughout the chamber, but the magnetic field directions are not aligned and fine adjustment of magnetic field strength is difficult
Solution Approach 1:
The patent merges a permanent magnet and an electromagnet into a single unit positioned at one location. This allows the magnetic fields from both sources to be aligned in the same direction, eliminating directional conflicts. The electromagnet's field strength can be continuously adjusted by controlling the current, enabling fine-tuning of the total magnetic field strength to achieve precise control over plasma density and etch rate uniformity across the wafer surface
Solution Approach 2:
The patent utilizes parameter changes by adjusting the current through the electromagnet to change the magnetic field strength dynamically. By varying the current parameter, the electromagnet's magnetic field can be tuned to either reinforce or cancel portions of the permanent magnet's field, allowing precise control of the net magnetic field strength. This parameter adjustment capability directly enables fine control of plasma density and etch rate uniformity
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
Achieves uniform plasma density and etch rate across the wafer surface by finely tuning magnetic fields, reducing etch rate deviations between the center and edge regions.
Implementation Method 1
a magnetic module including a permanent magnet and an electromagnet disposed vertically above the reaction chamber
Implementation Method 2
an electromagnet disposed to be perpendicular to the permanent magnet, and a DC power supply unit connected to the electromagnet and inputting power to the electromagnet
Implementation Method 3
a plasma generating device connected to the reaction chamber to generate plasma in the reaction chamber
Data Source
AI summary
A plasma processing apparatus using a magnetic field includes a reaction chamber, a plasma generating device connected to the reaction chamber to generate plasma in the reaction chamber, a substrate support disposed in a lower portion in the reaction chamber to support a wafer to be etched by the plasma, and a magnetic module including a permanent magnet and an electromagnet disposed vertically above the reaction chamber and a DC power supply unit connected to the electromagnet to input power to the electromagnet.