Nickel-Plated Chamber Components for Selective Plasma Etch
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Solution Overview
Problem
Conventional etching methods at low pressures suffer from decreased selectivity and increased etching of silicon, as the density of reactive components like fluorine radicals decreases, leading to undesired etching of silicon substrates during the etching of thermal oxide.
Innovation Solution
A semiconductor processing system with nickel-plated chamber components that scavenge excess radicals, allowing for low-pressure etching of thermal oxide with maintained selectivity by reducing unreacted radicals, which minimizes silicon etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If low pressure etching is used to enable etchants to reach the bottom of narrow and deep features, then etching capability in deep features is improved, but selectivity deteriorates due to decreased density of reactive components leading to increased silicon etching
Solution Approach 1:
A gas bypass system is introduced as an intermediary mechanism that delivers additional reactive species directly to the substrate surface. This mediator compensates for the insufficient reactive component density at low pressures, maintaining etch selectivity while enabling effective etching in deep, narrow features where conventional low-pressure etching would otherwise cause excessive silicon etching.
Solution Approach 2:
The system changes the parameter of reactive species delivery by introducing a bypass gas flow path that operates independently from the main chamber pressure. This allows selective enhancement of reactive component concentration at the substrate surface without increasing overall chamber pressure, thereby maintaining both deep feature etching capability and etch selectivity.
2Length of moving object
If conventional etching methods are used at low pressures, then processing of smaller semiconductor features is enabled, but selectivity is decreased leading to undesired silicon etching
Solution Approach 1:
The bypass gas delivery system acts as an intermediary that provides targeted reactive species supplementation. This enables precise control over the chemical environment at the substrate surface, allowing smaller semiconductor features to be processed with maintained selectivity by ensuring adequate reactive component concentration without relying solely on low-pressure conditions that reduce reactive species density.
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 system achieves high selectivity in etching thermal oxide over silicon, even at low pressures, with negligible silicon etching and increased thermal oxide etching, ensuring precise patterning for smaller semiconductor features.
Implementation Method 1
Nickel may scavenge fluorine radicals or hydrogen radicals, which may be responsible for undesired etching of silicon
Implementation Method 2
reacting the first mixture with the substrate to etch a first layer selectively over a second layer
Data Source
AI summary
Embodiments of the present technology may include a method of etching. The method may include mixing plasma effluents with a gas in a first section of a chamber to form a first mixture. The method may also include flowing the first mixture to a substrate in a second section of the chamber. The first section and the second section may include nickel plated material. The method may further include reacting the first mixture with the substrate to etch a first layer selectively over a second layer. In addition, the method may include forming a second mixture including products from reacting the first mixture with the substrate.