Ammonia Radical Generator Using UV Photodissociation
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Solution Overview
Problem
Existing semiconductor processes using inductively coupled plasma (ICP) sources for generating ammonia radicals are inefficient, costly, and damaging to low-k dielectric substrates, while ultraviolet (UV) sources consume excessive power and produce ozone, leading to inefficiencies and operational challenges.
Innovation Solution
A compact ammonia radical generator with a coaxial geometry using a high-power UV bulb surrounded by ammonia gas, where UV energy is absorbed by ammonia to break it into radicals and hydrogen, eliminating ozone production and reducing system complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inductively coupled plasma (ICP) sources are used to generate ammonia radicals, then radical generation is achieved, but the system becomes physically large, complex, and expensive, and substantial ion flux at relatively high ion energy is generated that is damaging to low-k dielectric substrates
Solution Approach 1:
The patent replaces the mechanical plasma generation system (ICP source with coils and electrodes) with a photochemical system using UV lamps. The UV photons directly dissociate ammonia molecules to generate radicals without requiring complex plasma generation equipment, thereby reducing system complexity while maintaining radical generation capability
Solution Approach 2:
The invention extracts and eliminates the harmful ion flux component from the radical generation process. By using UV photodissociation instead of plasma, the system generates only neutral radicals without the damaging ion flux that accompanies plasma-based methods, thus protecting low-k dielectric substrates
2Productivity
If inductively coupled plasma (ICP) sources are used to generate ammonia radicals, then radical generation is achieved, but the system becomes physically large, complex, and expensive
Solution Approach 1:
The patent replaces the bulky mechanical ICP source with compact UV lamp assemblies. The UV lamps can be positioned directly within the reaction chamber and require no external coil assemblies or complex power coupling systems, dramatically reducing the physical footprint of the radical generation system
3Device complexity
If ultraviolet (UV) sources are used to generate ammonia radicals, then system complexity and power consumption are reduced, but large amounts of electrical power are consumed and ozone is produced in the atmospheric air surrounding the UV source assemblies
Solution Approach 1:
The patent applies local quality by creating a nitrogen-purged environment around the UV lamps. By replacing atmospheric air with nitrogen gas in the immediate vicinity of the UV sources, the system maintains the UV radiation needed for radical generation while eliminating the oxygen that would otherwise form harmful ozone, thus locally modifying the gas composition to prevent harmful byproducts
Solution Approach 2:
The invention converts the potential harm of UV radiation (which can produce ozone when interacting with atmospheric oxygen) into a benefit by using nitrogen as a protective atmosphere. The nitrogen acts as a benign medium that allows UV transmission for radical generation while preventing ozone formation, effectively using an inert atmosphere to eliminate the harmful side effect
4Device complexity
If ultraviolet (UV) sources are used to generate ammonia radicals, then system complexity is reduced, but large amounts of electrical power are consumed
Solution Approach 1:
The patent optimizes the UV lamp operating parameters, specifically selecting wavelengths that match the absorption spectrum of ammonia for maximum photodissociation efficiency. By tuning the UV source parameters and using nitrogen to enhance the interaction between UV photons and ammonia molecules, the system achieves effective radical generation with reduced power consumption compared to conventional UV sources operating in air
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 solution significantly enhances efficiency by ensuring almost all UV energy is absorbed by ammonia, reducing system complexity and power consumption, and avoiding ozone-related challenges, resulting in a more cost-effective and substrate-friendly process.
Implementation Method 1
UV energy is absorbed by ammonia to break it into radicals and hydrogen
Implementation Method 2
the first quartz material of which the inner cylinder is comprised has at least 90% transmissivity to UV-C energy having a wavelength in the range from 200 nanometers to 220 nanometers
Implementation Method 3
the second quartz material of which the outer cylinder is comprised reflects UV-C energy having a wavelength in the range from 200 nanometers to 220 nanometers
Data Source
AI summary
An apparatus includes a base having first and second inlets. Inner and outer cylinders are disposed on the base, with the outer cylinder being concentric with the inner cylinder. An inner surface of the inner cylinder defines an internal volume. An outer surface of the inner cylinder and an inner surface of the outer cylinder define a chamber space. An ultraviolet lamp is disposed within the internal volume. A top cover is positioned over the inner and outer cylinders and in a sealing relationship with the cylinders. The top cover has a first passageway in flow communication with the chamber space, and a second passageway in flow communication with the internal volume. The first inlet is in flow communication with the chamber space and the second inlet is in flow communication with the internal volume. A system including a process chamber and an ammonia radical generator also is described.