Calibration method for photolithography line width test

Abstract

The invention provides a photolithographic line width test calibration method which comprises the following steps: S100, carrying out exposure on a photolithographic wafer; S101, standing the wafer subjected to exposure for several days; S102, testing the line widths of all points of the whole wafer by using a reference scanning electron microscope, and storing the line widths into a database; S103, carrying out daily calibration, testing the data of the first group of test points on the wafer, and comparing the tested data with data in the database so as to calculate a first difference value; and S104, judging whether the first difference value is within a standard and whether the first difference value needs to be adjusted; if not, completing the current calibration. Compared with the prior art, the method disclosed by the invention has the advantages that an error caused by the difference between the appearance of an etched wafer or a standard sample provided by a manufacturer and the appearance of a photolithographic sample is avoided during the measurement on photolithographic line width; in addition, calibration is not affected by appearance damage caused when electron beams bombard samples.

Description

technical field [0001] The invention relates to a method for testing and calibrating photolithographic line width, and relates to a semiconductor production process. Background technique [0002] The line width test (CD, Critical Dimension) in integrated circuit production is generally measured by optical microscope and scanning electron microscope. In advanced semiconductor processes, line width dimensions are getting smaller and smaller, so higher-resolution scanning electron microscopes are mainly used for testing. [0003] The basic working principle of the scanning electron microscope is that the electrons are emitted by the electron gun, accelerated under the electric field, focused by the electromagnetic lens, and become a very fine electron beam, which is scanned on the surface of the sample under the action of the scanning coil to stimulate various physical signals. Intensity varies with surface features. The signal is detected by a detector, amplified, and the mo...

AI Technical Summary

Problems solved by technology

However, the shape of the photoresist on the wafer is not consistent with the shape after etching, and the algorithm for calculating the line width is also different, and the line width test is greatly affected by these two factors, so the etching method is used. The scanning electron microscope calibrated after the wafer cannot guarantee the accuracy of the lithography line width test

Images