Hybrid Electron Beam and RF Plasma System for Ion Energy Control
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Solution Overview
Problem
High-energy ions in reactive ion etching (RIE) processes are difficult to control, leading to precision issues, charge-induced side effects, and feature-shape loading effects, which result in undesired profile variations and etching rate variations with aspect ratio, and challenges in controlling electron density and temperature for generating specific plasma species.
Innovation Solution
A hybrid electron beam and RF plasma system that forms a field of electrons in one region and a processing plasma in another, coupled region, where the energy from both sources is combined to control radical composition and plasma characteristics, allowing for precise modulation of electron temperature and plasma density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reactive ion etching (RIE) is used to etch substrate with high-energy ions, then etching capability is improved, but precision and control of ion energy distribution deteriorate
Solution Approach 1:
The system divides the plasma generation into two separate regions: a first region for generating plasma with radicals and a second region for generating a mono-energetic ion beam. This segmentation allows independent optimization of each function, achieving both high etching capability and precise ion energy control.
Solution Approach 2:
The invention extracts the ion acceleration function from the plasma generation region. Ions are generated in the first plasma region and then extracted into a second region where they are accelerated to a specific energy level, separating the functions of plasma generation and ion acceleration to achieve precise energy control.
2Ease of manufacture
If plasma is generated using electromagnetic fields in RIE, then etching process is enabled, but electron temperature control becomes difficult
Solution Approach 1:
The system separates plasma generation and ion acceleration into distinct regions with different electromagnetic field configurations. The first region uses electromagnetic fields for plasma generation, while the second region uses a different field configuration for precise ion acceleration, enabling independent control of each parameter.
Solution Approach 2:
The invention changes the electromagnetic field parameters between the two regions. The first region operates with parameters optimized for plasma generation, while the second region uses different parameters for precise ion acceleration, allowing independent optimization and control of each function.
3Device complexity
If broad ion energy distribution is used in RIE, then plasma generation is simplified, but etching precision deteriorates
Solution Approach 1:
The system segments the ion beam formation into two stages: initial plasma generation with broad distribution in the first region, followed by energy selection and mono-energetic beam formation in the second region. This segmentation maintains simplicity in plasma generation while achieving precision in the final ion beam.
Solution Approach 2:
The invention performs preliminary plasma generation in the first region to create a reservoir of ions, then uses the second region to select and accelerate only the desired energy component. This preliminary action simplifies the overall process while achieving precise energy control.
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 system enables precise control over ion energy distribution, reduces charge-induced side effects, and improves etching precision by tuning electron temperature and plasma density, resulting in a clean etch process with minimal byproducts and consistent profile variations across substrate features.
Implementation Method 1
a processing plasma in a second region of the wafer processing structure, the second region of the wafer processing structure being coupled to the first region of the wafer processing structure, the processing plasma being maintained by a combination of energy from a radiant energy source and from an electron beam formed from electrons in the field of electrons
Implementation Method 2
RIE in an inductively coupled plasma occurs when a plasma is generated using electromagnetic fields
Implementation Method 3
high-energy ions are accelerated to a surface exposed to radicals to etch away unwanted materials of the substrate
Data Source
AI summary
Embodiments of hybrid electron beam and RF plasma systems and methods are described. In an embodiment a method of using a hybrid electron beam and RF plasma system may include forming a field of electrons a first region of a wafer processing structure. Such a method may also include forming a processing plasma in a second region of the wafer processing structure, the second region of the wafer processing structure being coupled to the first region of the wafer processing structure, the processing plasma being maintained by a combination of energy from a radiant energy source and from an electron beam formed from electrons in the field of electrons. Additionally, the method may include controlling a radical composition and ions of the processing plasma by setting a ratio of the energy supplied to the processing plasma from the electron beam and the energy supplied to the processing plasma from the radiant energy source.