Spectrum detection method and system for fluorine atom density in plasma etching process

Abstract

The invention discloses a spectrum detection method and system for the fluorine atom density in a plasma etching process. The spectrum detection method and system have the advantages of no electron temperature influence, high accuracy, capability of being widely applied to various etching process conditions and the like. The method comprises the following steps: introducing argon gas with the known density into an etching reaction cavity containing fluorine atoms; detecting the intensity of two atomic emission spectral lines which are approximately same in excitation threshold energy and correspond to fluorine atoms and argon atoms respectively; calculating the fluorine atom density n[F] according to the intensity of the two atomic emission spectral lines of the fluorine atoms and the argon atoms by a calculation formula described in the specification, wherein in the formula, Q[F] represents the speed coefficient of the electron impact excited ground-state fluorine atoms, Q[Ar] represents the speed coefficient of the electron impact excited ground-state argon atoms, Q[Ar] / Q[F] is known physical quantity, I[F] is the corresponding spectral line intensity of the fluorine atoms, I[Ar] is the corresponding spectral line intensity of the argon atoms, and n[Ar] is the ground-state argon atom density.

Description

technical field [0001] The invention belongs to the field of semiconductor etching technology, and in particular relates to a spectral detection method and system for the density of fluorine atoms in the plasma etching technology. Background technique [0002] The plasma etching process is an indispensable process link in the modern VLSI manufacturing process, and is the only feasible method for directional etching of materials in the semiconductor manufacturing industry. The etching of materials such as silicon and silicon dioxide mainly relies on the chemical etching of silicon atoms by fluorine atoms. Therefore, the density of fluorine atoms is an important parameter affecting the etching rate and etching morphology, which needs to be detected in real time during the etching process. [0003] Industrial plasma etching machines are generally equipped with spectrometers to measure the emission spectrum of the plasma, and monitor the etching process by monitoring changes in...

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Problems solved by technology

[0004] The present invention aims to at least solve the technical problems in the prior art that are greatly affected by the temperature of the electrons and the measurement is inaccurate

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