An Electrode for Improving Process Plasma Uniformity

Abstract

The invention discloses an electrode for improving uniformity of process plasmas. The electrode includes a signal generator, a power amplifier, a first electrode and a second electrode. The first electrode and the second electrode face each other. The signal generator generates a low-frequency signal and a high-frequency signal. The low-frequency signal and the high-frequency signal pass through the power amplifier. The high-frequency signal is connected to the first electrode and the low-frequency signal is connected to the second electrode, or the low-frequency signal and the high-frequencysignal are both connected to the first electrode. A high-frequency source of the electrode for improving uniformity of process plasmas is used for improving an etching rate, and a low-frequency sourceof the electrode is used for inhibiting radial nonuniformity caused by super-high-frequency discharge. Moreover, the electrode has the characteristics of simple structure, low processing requirementsand high actual practicality.

Description

technical field [0001] The invention relates to the field of etching technology, in particular to an electrode for improving the uniformity of process plasma. Background technique [0002] During plasma etching, a capacitively coupled plasma source (CCP) is typically used. In the CCP discharge system, it contains a vacuum reaction chamber and two flat electrodes, such as figure 1 shown. In order to increase the etching rate (or plasma density), VHF (frequency greater than 60 MHz) is generally used to drive the discharge. Because when the discharge power and other discharge parameters are constant, a higher discharge frequency can generate a higher density plasma (directly affecting the etching rate). In addition, with the development of the etching process, the size of the wafer is increasing, and the size of the discharge chamber is also increasing, and the size of the electrode will be further increased. The electrode size in the new generation of etching machine will r...

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Problems solved by technology

[0008] However, for the Gaussian lens electrode, if the lens is a vacuum (or low-pressure gas) instead of a medium, then plasma will be generated under the substrate; moreover, the processing requirements of the chamber structure are harsh, and the size is slightly deviated. wave effects will not work

[0009] For the power phase modulation radio frequency discharge method, it is limited to the specific discharge gas and specific discharge power in the theoretical simulation, because the discharge gas is more complex in the experiment, it has not been realized yet; moreover, the plasma density and ion energy cannot be independently controlled, which This method is probably not applicable to large size electrodes

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