Cooling Chamber Outgas Control for Heated Ion Implantation
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Solution Overview
Problem
During heated ion implantation in semiconductor processing, outgassing of toxic materials from workpieces poses safety concerns due to unstable temperature and outgassing rates, limiting the selection of implantable species and causing processing delays.
Innovation Solution
A system and method that utilize a cooling chamber with a cooling apparatus, vacuum source, and purge gas to control the workpiece temperature and pressure, evacuating and diluting outgassed materials to prevent their release into the environment, using a scrubber to safely dispose of toxic gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the workpiece is heated to high temperatures for ion implantation, then the implantation characteristics are improved, but toxic materials outgas from the workpiece creating safety hazards
Solution Approach 1:
The patent extracts and removes toxic outgassed materials from the chamber environment using a vacuum source and purge gas system. The vacuum source evacuates outgassed materials while purge gas dilutes and directs them away from the workpiece, effectively separating the harmful outgassing from the implantation process environment.
Solution Approach 2:
The patent introduces an inert purge gas atmosphere into the chamber to dilute and displace toxic outgassed materials. This creates a safer environment by replacing potentially hazardous gases with an inert gas, preventing toxic materials from accumulating to dangerous concentrations while the implantation process continues.
2Temperature
If the workpiece is cooled quickly in a post-cool station, then the temperature is reduced, but significant outgassing has already occurred by that time
Solution Approach 1:
The patent applies preliminary action by implementing outgassing mitigation measures during the implantation process itself, rather than waiting until post-cooling. The vacuum source and purge gas system are activated concurrently with heating and implantation to prevent and remove outgassed materials in real-time, addressing the outgassing issue before it becomes a safety hazard.
Solution Approach 2:
The patent maintains continuous outgassing mitigation throughout the entire implantation process. The vacuum source continuously evacuates outgassed materials while purge gas continuously dilutes and directs them away, ensuring uninterrupted protection against toxic outgassing from the moment heating begins through the completion of implantation.
3Object-generated harmful factors
If species selection is limited to avoid toxic outgassing, then safety is improved, but the selection of implantable species is restricted
Solution Approach 1:
The patent converts the harmful effect of toxic outgassing into a manageable process parameter by implementing active removal and dilution systems. Instead of avoiding toxic species entirely, the system uses vacuum evacuation and purge gas dilution to control outgassed materials, allowing the use of a broader range of implantable species including those that would otherwise be restricted due to safety concerns.
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
This approach stabilizes the workpiece temperature and outgassing rate, ensuring a safe environment and maintaining processing efficiency without limiting high-temperature species implantation or causing delays, effectively mitigating toxic outgassing.
Implementation Method 1
A cooling apparatus is provided and configured to selectively cool the workpiece to a predetermined temperature
Implementation Method 2
A vacuum source is configured to selectively evacuate the chamber volume
Implementation Method 3
A purge gas source is configured to selectively provide a purge gas to the chamber volume
Implementation Method 4
A conventional high temperature ESC is cooled through radiation of energy to the chamber surfaces in the background
Implementation Method 5
a high temperature ESC is cooled through radiation of energy to the chamber surfaces
Data Source
AI summary
A workpiece processing system has a cooling chamber enclosing a chamber volume. A workpiece support within the cooling chamber supports a workpiece having a material with an outgassing temperature, above which, the material outgases an outgas material at an outgassing rate that is toxic to personnel. A cooling apparatus selectively cools the workpiece to a predetermined temperature. A vacuum source and purge gas source selectively evacuates and selectively provides a purge gas to the chamber volume. A controller controls the cooling apparatus to cool the workpiece to the predetermined temperature, where the one or more materials are cooled below the outgassing temperature. The vacuum source and purge gas source are controlled to provide a predetermined heat transfer rate while removing the respective outgas material from the chamber volume.