Ion Source Liner Lip Prevents Contaminant Entry
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Solution Overview
Problem
Ion source liners in ion implantation systems face premature failure due to particulate contaminants and corrosive gases, leading to reduced productivity and increased maintenance, as contaminants can enter gaps between electrodes and liners, causing electrical shorts and plasma instabilities.
Innovation Solution
An ion source liner with a raised lip is designed to prevent particulate contaminants from entering the annular gap between the electrode shaft and the liner, using a recessed plate with a lip that surrounds the hole, thereby preventing gravitational entry of contaminants and reducing gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liner is used in the ion source arc chamber, then the liner protects the chamber body from corrosive gases and extends component lifetime, but gaps between the electrode shaft and liner allow particulate contaminants to enter, causing electrical shorts and plasma instabilities
Solution Approach 1:
The patent introduces a lip structure that extends radially outward from the liner into the annular gap, adding a dimensional barrier that prevents particulate contaminants from entering the gap between the electrode shaft and liner. This radial extension creates a physical shield that blocks the harmful pathway without interfering with the functional gap.
Solution Approach 2:
The lip acts as an intermediary structure between the liner and the electrode shaft, creating a barrier that prevents direct contact between particulate contaminants and the critical gap area. The lip material serves as a mediating element that blocks contaminant transport while maintaining the necessary electrical and thermal functions of the original components.
2Reliability
If the gap between electrode shaft and liner is maintained for electrical isolation, then proper electrical function is preserved, but contaminants can enter the gap causing electrical shorts
Solution Approach 1:
The lip extends in the radial dimension into the annular gap, creating a three-dimensional barrier that blocks particulate contaminants from reaching the gap between the electrode shaft and liner. This maintains the electrical isolation function while preventing contaminant-induced electrical shorts.
Solution Approach 2:
The lip structure is pre-positioned to block the entry path into the annular gap before contaminants can cause electrical shorts. This preliminary protective barrier prevents the harmful effect from occurring in the first place, maintaining electrical isolation reliability.
3Ease of manufacture
If the liner structure is simplified for ease of manufacture, then manufacturing cost decreases, but contamination protection and gas sealing performance deteriorate
Solution Approach 1:
The liner is segmented into distinct functional zones: the main liner body for structural support and corrosion protection, and the lip extension for contamination blocking. This segmentation allows each part to be optimized for its specific function while maintaining overall manufacturability through standard fabrication processes.
Solution Approach 2:
The lip structure provides localized contamination protection at the critical interface between the electrode shaft and liner, while the rest of the liner maintains its simple cylindrical form for ease of manufacture. This local quality enhancement targets only the area where contamination protection is most needed.
Data Source
AI summary
An ion source has an arc chamber having a body defining and interior region. A liner defined an exposure surface of the interior region that is exposed to a plasma generated within the arc chamber. An electrode has a shaft with a first diameter that passes through the body and the liner. The electrode is electrically isolated from the body where the liner is a plate having a first surface with an optional recess having a second surface. A hole is defined through the recess for the shaft to pass through. The hole has a second diameter that is larger than the first diameter, and an annular gap exists between the plate and the shaft. The plate has a lip extending from the second surface toward the first surface that surrounds the hole within the recess and generally prevents particulate contaminants from entering the annular gap.