Ion Source Power Modulation for Contamination Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ion implantation systems face contamination issues due to continuous operation at full power, leading to inefficient utilization and increased maintenance, as contaminant particles are entrained in the ion beam and deposited on workpieces, even when not in use.
Innovation Solution
Implementing a system that rapidly modulates the ion beam's intensity between implantation and minimal power based on the presence or absence of a workpiece, using electrical control of electron flux within the ion source, rather than thermal control or arc voltage changes, to reduce contamination and improve duty cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ion beam operates continuously at full power, then the system maintains readiness for implantation, but contaminant particles are generated and deposited on workpieces even during transfers
Solution Approach 1:
The ion beam is operated in periodic cycles, switching between full power during implantation and minimal power during transfers. This periodic operation eliminates continuous contamination generation while maintaining system readiness through rapid power modulation capability.
Solution Approach 2:
The ion beam power is made dynamically adjustable between two states (full power and minimal power) based on operational requirements. This dynamic control allows the system to adapt power levels to actual needs, preventing contamination during non-implantation periods while maintaining implantation capability when required.
2Productivity
If the ion beam is maintained at full power continuously, then implantation can be performed immediately, but the utilization rate decreases due to inefficient operation during transfers
Solution Approach 1:
The system employs periodic full-power operation only during actual implantation cycles, with minimal power operation during transfers. This increases utilization rate by eliminating energy waste during non-productive periods while maintaining the ability to immediately perform implantation when needed.
Solution Approach 2:
The ion beam power parameter is changed between two discrete levels (full power and minimal power) based on the operational phase. This parameter modulation optimizes energy efficiency by matching power consumption to actual operational requirements, thereby improving utilization rate.
3Power
If thermal control or arc voltage changes are used to modulate ion beam intensity, then power can be reduced during transfers, but the response time is too slow to effectively prevent contamination
Solution Approach 1:
The patent replaces thermal control mechanisms with electrical control of electron flux. This substitution enables rapid modulation of ion beam intensity through electrical signals, achieving the necessary response speed to prevent contamination during transfers while maintaining power control capability.
Solution Approach 2:
The control method changes from thermal parameters to electrical parameters (electron flux control). This parameter change enables faster response times because electrical control can be modulated rapidly, allowing the ion beam power to be reduced quickly enough to prevent contamination during transfer operations.
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 significantly reduces contamination and increases the ion beam's utilization rate by minimizing particle generation during workpiece transfers and maintaining the ion beam at optimal power only during implantation, thus enhancing the efficiency and reducing maintenance needs.
Implementation Method 1
an ion source ionizes a desired dopant element, which is extracted from the source in the form of an ion beam
Implementation Method 2
a mass analysis magnet creating a dipole magnetic field to deflect various ions in an ion beam via magnetic deflection
Implementation Method 3
The mass of an ion relative to the charge thereon (i.e., charge-to-mass ratio) affects the degree to which it is accelerated both axially and transversely by an electrostatic or magnetic field
Implementation Method 4
The mass of an ion relative to the charge thereon (i.e., charge-to-mass ratio) affects the degree to which it is accelerated both axially and transversely by an electrostatic or magnetic field
Implementation Method 5
The ions of the beam penetrate the surface of the wafer to form a region of desired conductivity
Data Source
AI summary
A system and method for mitigating contamination in an ion implantation system is provided. The system comprises an ion source, a power supply operable to supply power to a filament and mirror electrode of the ion source, a workpiece handling system, and a controller, wherein the ion source is selectively tunable via the controller to provide rapid control of a formation of an ion beam. The controller is operable to selectively rapidly control power to the ion source, therein modulating a power of the ion beam between an implantation power and a minimal power in less than approximately 20 microseconds based, at least in part, to a signal associated with a workpiece position. Control of the ion source therefore mitigates particle contamination in the ion implantation system by minimizing an amount of time at which the ion beam is at the implantation current.