ICP Chamber Magnet Ring Layout for Uniform Plasma Etching
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Solution Overview
Problem
Inductively coupled plasma (ICP) process chambers produce non-uniform electric field distributions leading to non-uniform etch patterns on semiconductor substrates, such as M-shaped etch patterns, due to design constraints and asymmetric gas pumping, which degrade plasma uniformity and etch rate.
Innovation Solution
The substrate processing chamber incorporates magnets near induction coils and on the substrate support assembly to generate additional magnetic fields that confine and enhance plasma intensity, improving uniformity and etch rate by magnetizing plasma ions and inhibiting electron diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If inductive coils are used to generate plasma in ICP process chambers, then plasma generation is achieved, but non-uniform electric field distribution occurs leading to non-uniform etch patterns
Solution Approach 1:
The patent applies local quality by positioning magnets at specific locations around the chamber perimeter rather than uniformly distributing them. The magnets are placed at discrete positions to create localized magnetic field enhancements that specifically address edge uniformity issues in the plasma distribution, thereby improving etch pattern uniformity without requiring uniform magnetic field throughout the entire chamber.
Solution Approach 2:
The patent changes physical parameters by introducing magnetic field strength and distribution as additional control parameters. By adjusting the position, strength, and configuration of the magnets, the system modifies the plasma confinement parameters and electron diffusion characteristics, transforming the electric field distribution from non-uniform to more uniform, which directly addresses the etch pattern uniformity problem.
2Manufacturing precision
If magnets are added to enhance plasma uniformity, then plasma confinement and etch rate improve, but device complexity increases
Solution Approach 1:
The patent reduces complexity by applying magnets only where needed - at specific locations around the chamber perimeter - rather than implementing a uniform magnetic field system throughout. This localized approach achieves plasma uniformity improvement with minimal additional components, avoiding the complexity of a fully integrated magnetic field system.
Solution Approach 2:
The magnets serve as intermediary elements that mediate between the inductive coils and the plasma. Rather than directly controlling the plasma through complex electromagnetic field systems, the magnets provide a simpler intermediate mechanism for plasma confinement and uniformity control, reducing the overall system complexity while achieving the desired plasma characteristics.
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 magnetic fields enhance plasma uniformity and etch rate, reducing hardware damage risks and extending the plasma decay window, particularly benefiting edge uniformity and efficiency in semiconductor manufacturing.
Implementation Method 1
inductively coupled plasma (ICP) process chambers are used in semiconductor manufacturing and generally form plasmas by inducing current in a process gas disposed within the process chamber via one or more inductive coils disposed outside of the process chamber
Implementation Method 2
at least one magnet is coupled to a magnet power source and disposed outside of the radio frequency shield
Data Source
AI summary
The present disclosure provides a substrate processing chamber configured to produce an inductively coupled plasma. In one example, the substrate processing chamber has a chamber body and a substrate support assembly disposed within the chamber body. The substrate processing chamber has a lid assembly enclosing a processing region within the chamber body. The lid assembly has an inductive coil configured to generate a plasma within the processing region of the chamber body. A radio frequency shield encloses the inductive coil and at least one magnet is coupled to a magnet power source and disposed outside of the radio frequency shield.