Method for measuring thickness of edge film of silicon wafer

Abstract

A method for measuring the thickness of an edge film of a silicon wafer belongs to the technical field of thickness measurement of chemical mechanical polishing films. By use of a mathematical model provided in the invention, a measured curve of edge film thickness is corrected to be consistent with the actual curve of edge film thickness to the greatest extent, so that the measured value of edge film thickness can be used as the actual value of edge film thickness. The invention solves the problem of the prior art that the measured value of edge film thickness is distorted when the film thickness of the silicon wafer is measured by use of electric vortex, and has the advantages that only the mathematical model is needed to be corrected instead of the hardware equipment. When in use, only the simple off-line calibration is required, so as to avoid the influence on the yield of the chemical mechanical polishing process.

Description

technical field [0001] The invention relates to the technical field of chemical mechanical polishing film thickness measurement, in particular to a method for measuring the film thickness at the edge of a silicon wafer. Background technique [0002] Now that the wafer size has increased to 300mm, and will increase to 450mm in the near future, chips at the edge of the wafer have an increasing impact on the overall yield. Therefore, film thickness measurement at the edge of the silicon wafer during chemical mechanical polishing has become particularly important. [0003] Most of the copper film thickness and surface topography are measured by eddy current sensors before and after the chemical mechanical polishing process. The radius of the eddy current sensor probe is generally at least 6 ~ 8mm, such as figure 1 , figure 2 As shown, 6 and 7 are eddy-current sensors installed in pairs, and 8 is a silicon chip. During the measurement process, the silicon chip is figure 2 T...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the inaccurate problem of the edge film thickness value caused by the signal distortion existing when the existing eddy current sensor measures the edge film thickness, the present invention provides a method for measuring the edge film thickness of a silicon wafer. Make corrections to make it as consistent as possible with the real edge film thickness curve, and the edge film thickness value measured after using the present invention can be used as the real edge film thickness value

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