Cold Trap Filter Paddles for Ion Implantation Vacuum Systems
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Solution Overview
Problem
Conventional mesh pad filters in ion implantation systems are prone to rapid material buildup, reducing vacuum pump efficiency and increasing maintenance downtime, especially when switching between different dopant species, due to inadequate material removal and potential dangerous mixing of deposited materials.
Innovation Solution
A cold trap filter system with paddles cooled to specific temperatures to condense and deposit chemical species, combined with electrostatic attraction and heating to maintain surface temperatures above condensation points, minimizing downtime and maintaining vacuum capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mesh pad filter is placed within the source vacuum line to filter material, then material filtration is improved, but vacuum pump capabilities are reduced due to flow restriction and maintenance downtime increases
Solution Approach 1:
The invention extracts the filtering function from the mesh pad and relocates it to a cold trap positioned in the roughing vacuum line. The cold trap captures condensed material before it enters the roughing pump, separating the filtration function from the high vacuum line and restoring unobstructed flow to the vacuum system.
Solution Approach 2:
The cold trap serves as an intermediary component between the high vacuum line and roughing pump. It captures and condenses material in an intermediate location, preventing direct contamination of the roughing pump while maintaining efficient vacuum flow through the system.
2Loss of substance
If a mesh pad filter is used to capture material, then material removal is improved, but maintenance downtime increases due to frequent filter changes
Solution Approach 1:
The invention employs a disposable cold trap that can be easily replaced when full. Rather than maintaining and cleaning a mesh pad filter, the entire cold trap assembly is designed as a low-cost replaceable unit, minimizing maintenance complexity and downtime.
Solution Approach 2:
The cold trap is designed to be discarded after capturing a certain amount of material and replaced with a fresh unit. The captured material is recovered along with the cold trap, eliminating the need for filter cleaning or regeneration processes.
3Reliability
If a mesh pad filter captures material, then filtration is improved, but dangerous mixing of deposited materials occurs when changing source species
Solution Approach 1:
The invention extracts the captured material from the high vacuum environment where species changes occur and relocates it to the cold trap in the roughing line. This physical separation prevents contaminated material from mixing with materials from different species cycles.
Solution Approach 2:
The cold trap acts as an intermediary containment chamber that isolates material from different source species cycles. By capturing material before it enters the roughing pump, it prevents direct mixing of materials from n-type and p-type doping cycles.
4Productivity
If material is deposited in the roughing pump, then vacuum system operation continues, but pump life is reduced
Solution Approach 1:
The invention extracts material from the vacuum system flow before it can enter and deposit in the roughing pump. The cold trap captures condensed material in the roughing line, preventing it from reaching the pump interior and degrading pump components.
Solution Approach 2:
The cold trap serves as a protective intermediary between the vacuum line and roughing pump. It intercepts and condenses material in a location that protects the pump from contamination, extending pump life while maintaining continuous operation.
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 cold trap filter effectively removes chemical species without impairing vacuum capacity, reducing maintenance needs and preventing dangerous mixing, thus enhancing operational efficiency and safety.
Implementation Method 1
a cold trap filter system with paddles cooled to specific temperatures to condense and deposit chemical species
Implementation Method 2
combined with electrostatic attraction and heating to maintain surface temperatures above condensation points
Data Source
AI summary
A cold trap filter and method is provided for filtering chemical species from a vacuum system of an ion implantation system. A canister is in fluid communication with an exhaust of a high vacuum pump and an intake of a roughing pump used for evacuating an ion source chamber. One or more paddles are positioned within the canister, wherein each paddle has a cooling line in fluid communication with a coolant source. The coolant source passes a coolant through the cooling line, thus cooling the one or more paddles to a predetermined temperature associated with a condensation or deposition point of the chemical species, therein condensing or depositing the chemical species on the paddles while not interfering with a vacuum capacity of the high vacuum and roughing pumps. The paddles can also be electrically biased to electrostatically attract the chemical species to the paddles in one or more biasing steps.