High Secondary Electron Emission Electrode for Anisotropic Etching
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Solution Overview
Problem
Conventional etching techniques, such as reactive ion etching and electron beam etching, face limitations in achieving anisotropic etching profiles and selectivity at the nanometer scale, often damaging the substrate and reducing etch selectivity due to ion energy thresholds.
Innovation Solution
The method involves generating a plasma in a process chamber using low-frequency RF power applied to an electrode with a high secondary electron emission coefficient, accelerating electrons to form an electron beam that induces etching on a substrate, while controlling ion energy and plasma density to enhance etch selectivity and reduce substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional reactive ion etching is used to achieve anisotropic etching profiles, then directional etching capability is improved, but ion energy thresholds cause substrate damage and reduced etch selectivity
Solution Approach 1:
The patent introduces a specialized electrode as an intermediary component that converts ion bombardment into electron beam emission. The electrode with high secondary electron emission coefficient transforms the harmful ion energy into useful electron beams, which then perform the etching function without directly impacting the substrate, thus resolving the contradiction between achieving anisotropic profiles and avoiding substrate damage
Solution Approach 2:
The patent replaces the direct mechanical ion bombardment system with an electron beam system. Instead of using ion beams to directly etch the substrate (mechanical/physical process), the system uses electron beams to induce chemical reactions for etching, substituting a gentler electronic process for the harsh mechanical ion impact while maintaining etching effectiveness
2Object-affected harmful factors
If conventional electron beam etching is used to avoid substrate damage, then substrate integrity is improved, but the micrometer-scale beam cross section limits nanometer scale device formation
Solution Approach 1:
The patent applies dynamic control to the electron beam parameters, specifically modulating the beam energy and flux in real-time. By dynamically adjusting the electron beam characteristics and controlling plasma density, the system achieves both gentle substrate treatment and high-resolution nanometer-scale patterning capability
Solution Approach 2:
The patent changes key process parameters including electron beam energy, beam current density, and plasma gas composition to optimize both substrate protection and etching precision. By carefully controlling these parameters, the system achieves nanometer-scale manufacturing precision while maintaining substrate integrity
3Productivity
If high ion energy is used to increase etch rate, then productivity is improved, but etch selectivity is reduced
Solution Approach 1:
The patent changes the energy delivery mechanism from high-energy ions to controlled-energy electron beams. By adjusting electron beam parameters such as energy and flux density, the system achieves high etch rates through enhanced chemical reactivity while maintaining selectivity through precise spatial and temporal control of the electron beam
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 approach achieves improved etching uniformity and selectivity, with etch rates comparable to or exceeding conventional methods, while minimizing substrate damage through controlled electron beam energy and plasma processing, enabling precise nanoscale feature formation.
Implementation Method 1
The electrode is bombarded with the ions to cause the electrode to emit electrons and form an electron beam
Implementation Method 2
the emitted electrons are accelerated from the electrode through the plasma toward a substrate
Implementation Method 3
applying low frequency RF power to an electrode formed from a high secondary electron emission coefficient material disposed in the process volume, and generating a plasma comprising ions in the process volume
Data Source
AI summary
Embodiments described herein relate to apparatus and methods for performing electron beam reactive plasma etching (EBRPE). In one embodiment, an apparatus for performing EBRPE processes includes an electrode formed from a material having a high secondary electron emission coefficient. In another embodiment, methods for etching a substrate include generating a plasma and bombarding an electrode with ions from the plasma to cause the electrode to emit electrons. The electrons are accelerated toward a substrate to induce etching of the substrate.