Ion Source Repeller Shield Labyrinth Seal for Corrosion Protection
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Solution Overview
Problem
Conventional ion source seals, particularly those made of boron nitride, are prone to leakage due to corrosion from gases like fluorine, leading to reduced lifetime and frequent maintenance in ion implantation systems.
Innovation Solution
A labyrinth seal design is implemented, featuring a boron nitride seal with an annular groove and a liner lip that surrounds a hole, combined with an electrode lip, to create a labyrinth seal that reduces gas conductance and protects the seal from corrosive gases, thereby preventing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional boron nitride seal is used in the ion source, then the seal provides initial gas tightness, but the seal is corroded by corrosive gases (fluorine) over time, leading to leakage and reduced lifetime
Solution Approach 1:
A labyrinth seal structure is introduced as an intermediary protective feature between the corrosive gases and the boron nitride seal. The labyrinth seal comprises a series of concentric rings with progressively smaller diameters that create a tortuous path for gas flow, serving as a mediator that protects the main seal from direct corrosive attack while still maintaining gas tightness
Solution Approach 2:
The solution transitions from a simple linear seal interface to a three-dimensional labyrinthine structure with multiple concentric rings. This dimensional transformation creates a complex gas flow path that increases the effective path length and reduces direct exposure of the seal to corrosive gases, thereby extending seal lifetime
2Productivity
If the ion source operates with corrosive gases, then ion implantation process is enabled, but gas leakage occurs through seal degradation, damaging insulators and requiring frequent maintenance
Solution Approach 1:
The labyrinth seal structure serves as a pre-established protective barrier that cushions the main seal against corrosive gas attack before significant damage can occur. By providing this advance protection, the system maintains gas tightness and operational reliability for extended periods, reducing unplanned downtime and maintenance frequency
3Reliability
If a simple seal design is used, then the device structure is simple, but gas conductance is high and leakage occurs, reducing system reliability
Solution Approach 1:
The seal structure is segmented into multiple concentric rings with progressively smaller diameters, creating a series of discrete sealing zones. This segmentation divides the gas flow path into multiple stages, with each ring contributing to overall gas tightness while collectively reducing total gas conductance through the seal interface
Data Source
AI summary
An arc chamber liner has first and second surfaces and a hole having a first diameter. A liner lip having a second diameter extends upwardly from the second surface toward the first surface and surrounds the hole. An electrode has a shaft with a third diameter and a head with a fourth diameter. The third diameter is less than the first diameter and passes through the body and hole and is electrically isolated from the liner by an annular gap. The head has a third surface having an electrode lip extending downwardly from the third surface toward the second surface. The electrode lip has a fifth diameter between the second and fourth diameters. A spacing between the liner and electrode lips defines a labyrinth seal to generally prevent contaminants from entering the annular gap. The shaft has an annular groove configured to accept a boron nitride seal.