Method for realizing impedance matching in radio frequency transmission and impedance matching device

Abstract

The invention provides a method for realizing impedance matching in radio frequency transmission, which includes the following steps: calibration: a sensor is calibrated according to a load impedance detection result, and optimized matrix parameters are determined; detection: aimed at a current load, the sensor is used to acquire voltage and current information of the radio frequency transmission line, and according to the optimized matrix parameters, the module and phase of load impedance are obtained by calculation; adjustment: variable elements in a matching network are adjusted to realize impedance matching. Because the invention can use a high-precision impedance-measuring tool to calibrate the sensor, that is, the impedance |Z|<Theta measured by the impedance-measuring tool and the output signal An multiplied by 1 of the sensor are utilized to optimize the parameters in amplitude discrimination and phase discrimination algorithms, the affection of temperature, power and other factors on an analog circuit can be reduced, consequently, the measurement precision of the sensor is increased, and the speed and precision of impedance matching are ensured.

Description

technical field [0001] The invention relates to the technical field of plasma etching, in particular to a method for realizing impedance matching in radio frequency transmission and an impedance matching device. Background technique [0002] Plasma is widely used in the production process of semiconductor devices. In a plasma etch system, an RF power supply supplies power to the plasma chamber to generate the plasma. The plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals. These active particles interact with the wafer placed in the cavity and exposed to the plasma environment, making the surface of the wafer material Various physical and chemical reactions occur, thereby changing the surface properties of the material, and completing the etching of the wafer or other processes. [0003] The commonly used RF power supply has an operating frequency of 13.56MHz, an output impedance of 50Ω, and is connected to...

AI Technical Summary

Problems solved by technology

A major disadvantage of analog circuits is that they will be affected by factors such as power and temperature, resulting in changes in device or chip-related parameters.

That is, the load impedance calculated by using the voltage and current information of the RF transmission line collected by the sensor will have a certain deviation from the actual impedance value of the load, especially for some load impedances (such as the load impedance with a small modulus |Z|| impedance, or a load impedance whose impedance phase is close to +90° or -90°), this deviation is particularly severe

[0007] In short, due to the deviation characteristic caused by the sensor analog device, the matching path of the actuator in the matching device is poor, the matching time of the matching device is long, and the accuracy is poor; if it is serious, the matching device will not work normally and cannot be matched.

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