Platen Temperature Measurement via Clamping Current Waveform
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Solution Overview
Problem
Current methods for monitoring the temperature of a platen and workpiece during ion implantation in semiconductor fabrication are either costly, provide non-real-time data, or require specialized expertise for thermal imaging interpretation, hindering efficient process control.
Innovation Solution
A system that monitors the temperature of a platen and workpiece by analyzing the clamping current waveform, which changes with temperature, using a power supply, current sensor, and controller to determine temperature based on parameters like the area under the curve or leakage current, allowing for in-situ temperature measurement without external sensors or imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized workpieces with integrated temperature sensors are used to measure actual temperature, then measurement precision is improved, but productivity deteriorates due to loss of system time and increased cost of ownership
Solution Approach 1:
The platen's existing electrodes and dielectric material serve dual purposes: maintaining their primary electrostatic clamping function while simultaneously enabling temperature measurement through monitoring of clamping current waveform parameters. The system uses the platen's own structural components (electrodes and dielectric) as the sensing mechanism, eliminating the need for separate temperature sensors and specialized test workpieces.
Solution Approach 2:
The clamping current monitoring system serves multiple functions: it maintains electrostatic clamping of the workpiece while simultaneously providing real-time temperature measurement. The existing electrical components (power supply, electrodes, dielectric) are utilized for both their traditional purpose and temperature sensing, creating a multi-functional system that improves productivity without sacrificing measurement capability.
2Measurement precision
If infrared thermal imaging is used to create a thermal map of the workpiece, then temperature measurement capability is improved, but device complexity increases due to need for specialized interpretation expertise and equipment
Solution Approach 1:
The patent replaces complex optical thermal imaging systems with an electrical measurement approach. Instead of using infrared cameras and specialized software for thermal mapping, the system uses electrical current waveform analysis through the existing clamping circuitry. This substitution of measurement modality (from optical to electrical) dramatically reduces system complexity while providing comparable temperature information.
Solution Approach 2:
The clamping current waveform serves as an intermediary parameter that indirectly reflects temperature conditions. Rather than directly measuring temperature with complex thermal imaging equipment, the system monitors the electrical current flowing through the dielectric material, which changes predictably with temperature. This intermediary measurement approach simplifies the system while maintaining measurement capability.
3Measurement precision
If infrared thermal imaging is used for temperature measurement, then temperature data is obtained, but loss of time increases due to interpretation time adding to total fabrication process
Solution Approach 1:
The clamping current monitoring operates continuously throughout the ion implantation process without interruption. The temperature measurement is obtained in real-time as the process proceeds, eliminating the need for separate interpretation steps that would pause production. The measurement is integrated into the ongoing electrostatic clamping operation, ensuring continuous monitoring without adding time to the fabrication process.
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
Enables real-time, cost-effective temperature monitoring of the platen and workpiece during ion implantation, integrating seamlessly with existing systems and providing feedback for optimal temperature control, reducing fabrication time and costs.
Implementation Method 1
a power supply to provide a clamping voltage and a clamping current to the at least one electrode
Implementation Method 2
Since the platen is made of a dielectric material, its properties, such as resistivity and conductivity, can change as a function of temperature
Implementation Method 3
a current sensor to monitor clamping current
Data Source
AI summary
A system and method for monitoring the temperature of a platen and a workpiece disposed on that platen is disclosed. Since the platen is a dielectric material, its properties, such as resistivity and conductivity, may change as a function of temperature. By understanding the relationship between these parameters and temperature, it may be possible to indirectly determine the temperature of the platen. For example, the platen may be in electrical communication with a power supply, which provides a clamping voltage for the workpiece. By monitoring the current waveform associated with the clamping voltage, it is possible to determine changes in the characteristics of the platen. Based on these changes, the temperature of the platen may be calculated.