Twist Axis Warming for Cold Ion Implantation
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Solution Overview
Problem
Ion implantation systems face challenges in maintaining the rotation of seals and bearings due to increased viscosity caused by cooling, which can lead to undesired heating and warping of workpieces, and difficulties in achieving low-temperature implantation without component freezing or failure.
Innovation Solution
A method and system for heating seals and bearings in ion implantation systems using a heater assembly to decrease fluid viscosity, allowing for smooth rotation and counter-rotation of the end effector, thereby overcoming the effects of increased viscosity and maintaining operational efficiency at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the electrostatic chuck is cooled to low temperatures for ion implantation, then undesired heating of the workpiece is reduced, but the viscosity of fluids in seals and bearings increases, causing rotation problems
Solution Approach 1:
The system divides the temperature control into separate zones: the electrostatic chuck is cooled to low temperatures for workpiece processing, while the seal and bearing areas are heated to maintain proper fluid viscosity. This spatial segmentation allows each component to operate at its optimal temperature independently.
Solution Approach 2:
Different thermal conditions are applied to different parts of the system. The electrostatic chuck region maintains low temperature for workpiece cooling, while the seal and bearing regions are locally heated to prevent fluid solidification. This local quality approach ensures each component experiences the temperature it needs for proper function.
2Reliability
If the end effector is rotated to warm seals and bearings, then fluid viscosity decreases and rotation improves, but workpiece heating may occur
Solution Approach 1:
The system performs preliminary rotation of the end effector before low-temperature ion implantation begins. This preliminary action warms the seals and bearings in advance, ensuring proper fluid viscosity and rotation capability before the cooling process starts, thereby avoiding the need for rotation during cold operation.
Solution Approach 2:
The end effector undergoes periodic rotation at controlled intervals to generate frictional heat in the seals and bearings. This periodic action maintains fluid viscosity within acceptable ranges without requiring continuous rotation, minimizing energy consumption and reducing the risk of workpiece heating.
3Temperature
If chilled fluid is circulated through the chuck for cooling, then workpiece temperature is controlled, but mechanical density of components prevents easy integration
Solution Approach 1:
The chilled fluid circulation system serves multiple functions: it cools the electrostatic chuck for workpiece temperature control, cools the end effector structure, and provides a thermal management pathway for the sealing and bearing components. This multi-functionality reduces the need for separate cooling systems and simplifies overall system integration.
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 effectively reduces the viscosity of ferrofluids and lubricating oils, enabling the end effector to rotate freely and maintain alignment, preventing workpiece damage and ensuring accurate ion implantation by providing controlled heating to seals and bearings.
Implementation Method 1
a viscosity of fluids involved therein is deleteriously increased
Implementation Method 2
One or more heater assemblies positioned proximate to the bearing and seal are configured to selectively provide a predetermined amount of heat to the bearing and seal
Data Source
AI summary
A method for warming a rotational interface in an ion implantation environment provides a scan arm configured to rotate about a first axis and an end effector coupled to the scan arm via a motor to selectively secure a workpiece. The end effector is configured to rotate about a second axis having a bearing and a seal associated with the second axis and motor. The motor is activated, and the rotation of motor is reversed after a predetermined time or when the motor faults due to a rotation the end effector about the second axis. A determination is made as to whether the rotation of the end effector about the second axis is acceptable, and the scan arm is reciprocated about the first axis when the rotation of the end effector is unacceptable, wherein inertia of the end effector causes a rotation of the end effector about the second axis.