RF Reference Box Calibration for Direct-Drive Power Impedance Matching
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Solution Overview
Problem
Plasma processing systems face challenges in efficiently delivering and calibrating radiofrequency (RF) power due to non-standard impedances, leading to inconsistencies in RF power transmission and plasma generation in semiconductor wafer processing.
Innovation Solution
A direct-drive RF power supply system with a reference box and calibration method that converts non-standard input impedances to a reference output impedance of 50 ohms, using a radiofrequency calibration system and power meter to adjust and ensure accurate RF power delivery to the plasma processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If non-standard impedance is used in RF power supply, then device complexity is reduced, but RF power transmission consistency deteriorates
Solution Approach 1:
The patent introduces a reference box as an intermediary device between the RF power supply and the plasma processing chamber. This reference box contains a reference circuit that converts non-standard impedance to standard 50 ohm impedance, serving as a mediator that enables consistent RF power transmission without requiring the entire RF power supply system to be complex
2Reliability
If impedance conversion is implemented, then RF power transmission consistency is improved, but device complexity increases
Solution Approach 1:
The patent segments the RF power supply system into distinct functional modules: the main RF power supply unit and a separate reference box containing the impedance conversion circuit. This segmentation allows the impedance conversion function to be added without redesigning the entire RF power supply system, thus limiting the increase in overall device complexity
3Measurement precision
If calibration system is added, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The reference box serves multiple functions simultaneously: it acts as an impedance conversion device, a calibration standard, and a measurement reference point. By combining these functions into a single universal device, the patent improves measurement precision without proportionally increasing device complexity
Data Source
AI summary
A radiofrequency calibration system for a direct-drive radiofrequency power supply includes a reference box that includes a reference circuit for converting a non-reference input impedance to a reference output impedance. The reference box has an input connector electrically connected to a radiofrequency output coupling of the direct-drive radiofrequency power supply. A radiofrequency power meter has a radiofrequency power input electrically connected to an output connector of the reference box. The radiofrequency power meter has an input impedance and an output impedance that substantially match the reference output impedance of the reference box. A cable has a first end electrically connected to a radiofrequency power output of the radiofrequency power meter and a second end connected to a test load that has an impedance that substantially matches the reference output impedance of the reference box. A controller is connected in data communication with a data interface of the radiofrequency power meter.