Pressurized Liquid Feed for Ion Source Species Changeover
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Solution Overview
Problem
Current ion implantation systems face challenges in efficiently providing metal ions, such as aluminum, due to issues with vaporizers' long warm-up and cool-down times, and the deposition of insulating compounds leading to high voltage instabilities and ion dosage variations.
Innovation Solution
An ion source system with a reservoir containing a liquid source species, coupled to the arc chamber via a conduit, where a liquid control apparatus manages the liquid volume using gas pressure and flow control, allowing for rapid switching between ion species and maintaining plasma purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a vaporizer is used to supply metal vapor to the ion source, then adequate vapor pressure can be achieved, but the system requires long warm-up and cool-down times
Solution Approach 1:
The patent extracts the harmful insulating compounds (oxides, chlorides, nitrides) from the vapor supply system by using a cold trap positioned between the vaporizer and ion source. This allows the vaporizer to operate at high temperatures for adequate vapor pressure while preventing contamination that would require cool-down time
Solution Approach 2:
The cold trap acts as an intermediary component between the vaporizer and ion source. It captures and removes insulating compounds from the metal vapor stream, allowing continuous operation without warm-up or cool-down delays while maintaining pure vapor supply to the ion source
2Power
If metal-containing compounds are placed inside the arc chamber, then beam current can be attained, but insulating compounds deposit on electrodes causing high voltage instabilities
Solution Approach 1:
The patent removes insulating compounds from reaching the arc chamber electrodes by using a cold trap to capture oxides, chlorides, and nitrides in the vapor stream. This extraction prevents deposition on electrodes while still allowing adequate metal vapor to reach the ion source for beam current generation
Solution Approach 2:
The patent converts the harmful effect of insulating compound formation into a beneficial separation process. The cold trap utilizes the tendency of these compounds to condense at lower temperatures to selectively remove them from the vapor stream, transforming a reliability problem into a purification mechanism
3Power
If compounds like aluminum oxide, aluminum chloride, and aluminum nitride are used as source material, then acceptable beam currents are achieved, but deposition on electrodes occurs in 5-10 hours
Solution Approach 1:
The cold trap continuously extracts insulating compounds from the vapor stream, preventing their deposition on electrodes. This extends the operational duration of the ion source from 5-10 hours to significantly longer periods by eliminating the deposition mechanism while maintaining beam current
Solution Approach 2:
The system discards insulating compounds at the cold trap before they can reach and deposit on the arc chamber electrodes. This selective discarding of harmful components allows the ion source to operate continuously with extended intervals between maintenance cycles
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 solution extends the operational life of the ion source, reduces transition time between species, and increases productivity by providing a stable and pure plasma, thus enhancing the overall ion implantation system's efficiency and longevity.
Implementation Method 1
a gas source fluidly coupled to the reservoir, wherein the gas source is configured to selectively supply a gas to the reservoir at a predetermined pressure
Implementation Method 2
A heat source is further provided in thermal communication with the reservoir, wherein the heat source is configured to selectively heat the reservoir
Implementation Method 3
wherein the heat source comprises plasma generated within the arc chamber volume, and wherein the plasma is configured to heat the liquid
Data Source
AI summary
An ion source has an arc chamber defining an arc chamber volume. A reservoir is coupled to the arc chamber, defining a reservoir volume. The reservoir receives a source species to define a liquid within the reservoir volume. A conduit fluidly couples the reservoir volume to the arc chamber volume. First and second openings of the conduit are open to the respective reservoir and arc chamber volume. A heat source selectively heats the reservoir to melt the source species at a predetermined temperature. A liquid control apparatus controls a first volume of the liquid within the reservoir volume to define a predetermined supply of the liquid to the arc chamber volume. The liquid control apparatus is a pressurized gas source fluidly coupled to the reservoir to supply a gas to the reservoir and provide a predetermined amount of liquid to the arc chamber.