Ion Source Wiper Assembly for Aperture Cleaning
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Solution Overview
Problem
Ion source extraction apertures suffer from undesirable deposits, such as tungsten, carbon, and boron, which affect beam uniformity and ion source lifetime, and conventional cleaning techniques are time-consuming, impacting throughput and beam current levels.
Innovation Solution
A wiper assembly positioned outside the arc chamber, configured to extend and retract to clean the extraction aperture, utilizing bristles made of refractory materials to remove deposits quickly and efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning techniques using cleaning gases are used, then deposits are removed from the extraction aperture, but the cleaning process takes 10-60 minutes which reduces throughput
Solution Approach 1:
The patent replaces the chemical cleaning system (cleaning gases) with a mechanical cleaning system (wiper assembly with bristles). The wiper assembly physically contacts and removes deposits from the extraction aperture through mechanical action, eliminating the need for lengthy chemical cleaning processes and significantly reducing cleaning time while maintaining effective deposit removal.
Solution Approach 2:
The patent extracts the cleaning function from the chemical gas phase and implements it as a separate mechanical component (wiper assembly) that can be independently controlled and operated. This allows the cleaning operation to be performed quickly on demand without affecting the ion beam generation process, thereby improving throughput while maintaining cleaning effectiveness.
2Manufacturing precision
If beam current levels are reduced to improve beam uniformity, then beam uniformity improves, but throughput and processing speed decrease
Solution Approach 1:
The patent performs preliminary cleaning action by removing deposits from the extraction aperture before ion beam extraction begins. By pre-cleaning the aperture with the wiper assembly, the system eliminates the need to reduce beam current for uniformity compensation, allowing operation at optimal current levels that maintain both beam uniformity and high throughput.
3Productivity
If dopant gas is provided to the arc chamber for ionization, then ion beam is generated, but undesirable deposits form on the extraction aperture over time
Solution Approach 1:
The patent implements a self-service cleaning mechanism where the wiper assembly is integrated into the ion source system and can autonomously clean the extraction aperture without external intervention. The controller automatically activates the wiper assembly to remove deposits formed during normal ion beam generation, allowing the system to maintain itself and continue productive operation without manual maintenance or gas interruptions.
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 wiper assembly effectively removes deposits in a matter of seconds, improving beam uniformity, maintaining higher beam current levels, and extending ion source lifetime, thereby enhancing throughput and dose uniformity at the workpiece plane.
Implementation Method 1
A wiper assembly includes a wiper positioned outside the arc chamber in a parked position and configured to be driven from the parked position to operational positions to clean the extraction aperture
Data Source
AI summary
An ion source includes an arc chamber housing defining an arc chamber having an extraction aperture, and a wiper assembly comprising a wiper positioned outside the arc chamber in a parked position and configured to be driven from the parked position to operational positions to clean the extraction aperture. A wiper assembly for an ion source includes a wiper configured to be positioned outside an arc chamber of the ion source when in a parked position and driven from the parked position to operational positions to clean an extraction aperture of the ion source.