Dielectric Injector Plasma Processing for Vertical Ion Control
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Solution Overview
Problem
Conventional plasma processing apparatuses face challenges in achieving uniform plasma density and low electron temperature at low pressure, leading to non-vertical ions and device damage, which are unsuitable for precision processing in nanometer-scale semiconductor fabrication.
Innovation Solution
The method involves generating an electron-beam sustained plasma (ESP) with uniform density and low electron temperature by accelerating electrons from a source chamber through a dielectric injector into a processing chamber, maintaining a negative electric potential in the source chamber and a greater potential in the processing chamber, and using a dielectric injector to control plasma properties like ion verticality and energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plasma processing is used at low pressure, then processing speed is improved, but plasma uniformity deteriorates and electron temperature increases causing device damage
Solution Approach 1:
The plasma processing system is divided into two separate chambers: a source chamber for generating plasma and an processing chamber for substrate treatment. This segmentation allows independent optimization of plasma generation conditions and processing conditions, enabling uniform plasma density at low pressure while controlling electron temperature to prevent device damage.
Solution Approach 2:
A magnetic field is introduced as an intermediary between the source chamber and processing chamber. The magnetic field confines and controls electron motion, enabling uniform plasma distribution in the processing chamber while maintaining low electron temperature. The magnetic field acts as a mediator that transfers energy uniformly without direct electron-substrate contact.
2Productivity
If high plasma density is achieved, then etch rate is improved, but ion verticality deteriorates leading to profile control issues
Solution Approach 1:
The system dynamically controls plasma parameters by independently adjusting power input in the source chamber and magnetic field strength. This dynamic control enables maintaining high plasma density for fast etching while simultaneously controlling ion directionality to achieve vertical profiles and precise shape control.
Solution Approach 2:
The invention changes multiple plasma parameters simultaneously: plasma density is increased to improve etch rate, while electron temperature is controlled through magnetic confinement to maintain ion verticality. By changing these parameters independently through the two-chamber design, both high productivity and shape control are achieved.
3Object-affected harmful factors
If electron temperature is reduced for device safety, then device damage is prevented, but plasma reactivity deteriorates
Solution Approach 1:
The two-chamber design segments the system so that electron generation occurs in the source chamber where high temperature can be maintained for reactivity, while the processing chamber maintains low electron temperature to prevent device damage. This spatial segmentation resolves the contradiction between reactivity and device safety.
Solution Approach 2:
The magnetic field serves as an intermediary that enables plasma reactivity without direct high-energy electron-substrate interaction. It confines electrons to generate reactive species while directing them away from the substrate, maintaining both plasma reactivity and device safety.
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 enables precise control of plasma properties, producing absolutely vertical ions and uniform plasma density, suitable for advanced semiconductor processing such as high aspect ratio contact etches and atomic level etch/deposition processes, improving precision and reducing device damage.
Implementation Method 1
generating an electric potential gradient between the source chamber and a processing chamber by applying a first negative direct current (DC) voltage to the source chamber and a ground voltage to the processing chamber
Implementation Method 2
accelerating the electrons from the source chamber through a dielectric injector and into the processing chamber using the electric potential gradient
Implementation Method 3
generating an electron-beam sustained plasma (ESP) in the processing chamber using the electrons from the source chamber
Data Source
AI summary
A method of plasma processing comprises generating electrons in a source chamber, generating an electric potential gradient between the source chamber and a processing chamber by applying a first negative direct current (DC) voltage to the source chamber and a ground voltage to the processing chamber, accelerating the electrons from the source chamber through a dielectric injector and into the processing chamber using the electric potential gradient, and generating an electron-beam sustained plasma (ESP) in the processing chamber using the electrons from the source chamber.