Chemical and mechanical planarization online terminal detection method based on spectrums

Abstract

The invention discloses a chemical and mechanical planarization online terminal detection method based on spectrums. According to the method, firstly, according to refractive indexes n, extinction coefficients k and target film thickness d of a polished thin film and base material, a theoretical spectrum curve is calculated, then a wavelength area of the curve is selected, and calculation of all wavelength values lambda hi corresponding to relative reflectivity maximum value points, the wavelength number a corresponding to the maximum value points, wavelength values lambda lk corresponding torelative reflectivity minimum value points and the wavelength number b corresponding to the minimum value points in the area is carried out. Original spectrum data in a polishing process is collectedin real time to obtain a smoothing spectrum curve, corresponding parameters of a smoothing spectrum curve zone of an area in which the wavelength is identical to that of the wavelength area are selected, and the differences between every two groups of data are calculated. If the differences are smaller than a preset threshold value, a planarization process is stopped. By means of the method, interference caused by detecting the changes of light intensity signals can be removed, there is no need to uniformize the detected spectrums, the calculation time is shortened, and meanwhile, the detection precision and consistency of the signals are improved.

Description

technical field [0001] The invention belongs to the technical field of detecting grinding completion in a grinding or polishing process, and in particular relates to an on-line endpoint detection method based on spectrum used in chemical mechanical planarization equipment. Background technique [0002] With the rapid development of the semiconductor industry, the feature size of integrated circuits tends to be miniaturized, and semiconductor chips continue to develop in the direction of small volume, high circuit density, fast speed, and low power consumption. Integrated circuits have now entered the ULSI sub-micron technology stage. With the gradual increase of the diameter of the silicon wafer, the width of the reticle in the component is gradually reduced, and the number of metal layers is increased. Therefore, the high planarization of the surface of the semiconductor film has an important impact on the high performance, low cost, and high yield of the device. Therefore,...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to propose a spectrum-based detection technology for the existing line end point detection technology that is susceptible to interference caused by changes in the detected light intensity signal caused by power supply voltage fluctuations or other factors, and the increase in computing time due to normalization processing. Online endpoint detection method to improve signal detection accuracy and detection consistency

Images