Dynamic Threshold Arc Detection Circuit for Ion Implantation
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Solution Overview
Problem
Ion implantation systems face challenges in detecting and mitigating arcs between high voltage electrodes, leading to erratic ion beam currents and non-uniform ion implantations, especially on larger wafers, due to fixed threshold current limitations in conventional arc protection circuits.
Innovation Solution
An arc detection circuit that uses dynamic detection parameters, such as varying current or voltage thresholds, to detect arcs and trigger an arc quenching mechanism, incorporating high voltage high speed switching circuits to quickly extinguish arcs and minimize ion beam disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold current is used in conventional arc protection circuits, then the circuit structure is simple, but the arc detection precision deteriorates due to inability to adapt to different process recipes and beam positions
Solution Approach 1:
The patent implements dynamic threshold adjustment by making the detection threshold a variable parameter that changes based on beam position and process recipe. The control system continuously adapts the threshold value during ion implantation operations, transforming the static fixed threshold into a dynamic adaptive threshold that maintains optimal arc detection precision across varying operating conditions.
Solution Approach 2:
The patent changes the detection threshold parameter from a fixed constant to a variable that depends on process conditions. By adjusting the threshold parameter dynamically based on beam position and process recipe characteristics, the system maintains high arc detection precision without requiring overly complex circuit architecture.
2Measurement precision
If arc detection uses adaptive parameters for different process recipes and positions, then arc detection precision improves, but the device complexity increases due to additional control circuitry
Solution Approach 1:
The control system serves multiple functions: it manages the ion beam scanning process, adjusts detection thresholds dynamically, and detects arcs. By integrating these functions into a single multi-functional control system rather than separate dedicated circuits for each function, the patent achieves high arc detection precision without proportionally increasing overall system complexity.
Solution Approach 2:
The system uses programmable parameter adjustment where the threshold values are stored as data that can be selected and modified based on process recipes. This software-based parameter management approach is more space-efficient than hardwired analog circuits, achieving adaptive precision with minimal additional physical circuitry.
3Object-affected harmful factors
If high voltage high speed switching circuits are used to quench arcs quickly, then ion beam disruption is reduced, but the device complexity and cost increase
Solution Approach 1:
The system performs preliminary preparation by pre-configuring the high voltage switching circuits and establishing detection thresholds before ion implantation begins. The arc quenching mechanism is pre-positioned and ready to activate immediately upon arc detection, minimizing the actual disruption time to the ion beam while avoiding the need for continuously complex active control during the entire implantation process.
Solution Approach 2:
The high voltage switching circuits enable the system to rapidly skip through the arc event by quickly quenching it within microseconds. This rapid transient response minimizes the duration of ion beam disruption, achieving the goal of reducing harmful effects while the switching circuit remains dormant most of the time, thereby limiting its impact on overall system complexity.
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 mitigates ion beam disruption and speeds up beam current recovery by adapting to different process recipes and positions within the ion implantation process, ensuring more uniform ion implantations and reducing waste on larger wafers.
Implementation Method 1
arcing between the various high voltage electrodes and other nearby parts
Implementation Method 2
A first arc type 12 occurs between an ion source electrode 14 (which is at a positive potential) and an extraction ground electrode 16
Implementation Method 3
incorporating high voltage high speed switching circuits to quickly extinguish arcs and minimize ion beam disruption
Implementation Method 4
an ion source ionizes a desired dopant element, and the ionized impurity is extracted from the ion source as a beam of ions
Implementation Method 5
The ion beam is directed (e.g., swept) across respective workpieces to implant ionized dopants within the workpieces
Data Source
AI summary
The present invention is directed to circuits, systems, and methods to quickly to quench an arc that may form between high voltage electrodes associated with an ion source to shorten the duration of the arc and mitigate non-uniform ion implantations. In one example, an arc detection circuit for detecting an arc in an ion implantation system includes an analog-to-digital converter (ADC) and an analysis circuit. The ADC is configured to convert a sensing current indicative of a current being supplied to an electrode in the ion implantation system to a digital current signal that quantifies the sensing current. The analysis circuit is configured to analyze the digital current signal to determine if the digital current signal meets threshold parameter value and in response to the digital current signal meeting the threshold parameter value, provide an arc detection signal to a trigger control circuit that activates an arc quenching mechanism.