Ion Implanter Faraday Flag Cooling and Deposition Control
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Solution Overview
Problem
Ion implanters face issues with high deposition rates of materials on faraday flags due to heat dissipation limitations in evacuated regions, leading to increased component temperatures and material flaking, which affects the quality of semiconductor processing and requires frequent maintenance.
Innovation Solution
Incorporating a thermally conductive strike plate with a cooling system and a cold trap to manage heat dissipation and reduce material deposition, utilizing a conductive strike plate coupled to a circuit for monitoring ion beam current and a cold trap to attract and retain sputtered material, thereby controlling component temperatures and minimizing film buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If radiation heat dissipation is used for faraday flag in evacuated region, then heat dissipation is limited, but component temperature increases leading to high deposition rates
Solution Approach 1:
A thermally conductive material is introduced as an intermediary between the faraday flag and the strike plate. This mediator efficiently transfers heat away from the faraday flag through thermal conduction, enabling effective heat dissipation in the evacuated region without requiring convection or radiation alone.
Solution Approach 2:
A fluid cooling system is implemented where a coolant fluid circulates through channels in the strike plate to actively remove heat from the faraday flag assembly. This hydraulic cooling mechanism provides controlled heat dissipation that overcomes the limitations of passive radiation cooling in vacuum environments.
2Productivity
If high beam flux is used for ion implantation, then processing efficiency increases, but material deposition and flaking increase
Solution Approach 1:
The cold trap, maintained at low temperature, is strategically positioned to intercept and condense sputtered material that would otherwise deposit on critical components. By converting the harmful sputtered material into a controlled deposition on the cold trap surface, the system protects the faraday flag and other components from excessive material buildup and flaking.
Solution Approach 2:
The system actively controls the temperature of the faraday flag and surrounding components to optimize the balance between processing efficiency and material deposition. By maintaining lower component temperatures through active cooling, the system reduces thermal-driven deposition rates while still allowing high beam flux processing.
3Reliability
If frequent maintenance is performed to remove deposited material, then component quality is maintained, but productivity decreases
Solution Approach 1:
The cold trap is positioned to preemptively capture sputtered material before it can deposit on critical components like the faraday flag. This preliminary action of material interception prevents excessive buildup on sensitive parts, extending maintenance intervals while maintaining component quality and system reliability.
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 solution significantly reduces material deposition rates, improves the quality of semiconductor processing, and extends maintenance schedules by effectively managing heat dissipation and film buildup within the ion implanter.
Implementation Method 1
A base supports the strike plate and includes a thermally conductive material surrounding at least a portion of an outer perimeter of the strike plate to conduct heat energy away from the strike plate
Implementation Method 2
Located below the strike plate is a cold trap, which is a thermally regulated structure. The cold trap is designed to attract sputterred material and reduce film buildup within the ion implanter
Implementation Method 3
A faraday flag structure has a conductive strike plate coupled to a circuit for monitoring ions striking the strike plate to obtain an indication of the ion beam current
Data Source
AI summary
A system for controlling the temperature of a semiconductor workpiece processing tool and surrounding structure, thereby reducing the deposition rates within an ion implanter. A faraday flag structure comprising a conductive strike plate coupled to a circuit for monitoring ions striking the strike plate to obtain an indication of the and a base supporting the strike plate that includes a thermally conductive material surrounding at least a portion of an outer perimeter of the strike plate. The faraday flag structure base defines a conduit for routing coolant through the thermally conductive material surrounding the strike plate. Positioned below the faraday flag is a thermally controlled cold trap that receives and retains foreign material appearing in ion implanter.