Calibration method of ellipsometer

A technology of ellipsometer and calibration method, which is applied in the direction of polarization influence characteristics, etc., can solve problems such as complex system structure, human adjustment error, and low calibration accuracy of polarizer angle, and achieve simple calibration process, simplified measurement process, and improved measurement The effect of precision

Inactive Publication Date: 2013-01-16
INST OF MICROELECTRONICS CHINESE ACAD OF SCI +1
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Problems solved by technology

In this calibration method, not only the analyzer needs to be rotated, but also the polarizer P needs to be rotated electrically or manually. When the polarization direction of the polarizer is determined, the angle of the polarizer needs to be adjusted manually or electrically. In this case, Due to the instability of the mechanical structure and/or the error of human operation, there will be an error between the actual angle and the angle that needs to be set, which will easily lead to the inaccuracy of the reference sample measurement
Therefore, when using this method, the angular calibration accuracy of the polarizer is relatively low, which limits the measurement accuracy of the ellipsometer
[0007] The incident angle of light in the ellipsometer can be obtained by manual measurement, but due to the limited

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  • Calibration method of ellipsometer
  • Calibration method of ellipsometer
  • Calibration method of ellipsometer

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Effect test

Embodiment 1

[0115] as figure 1 The shown structure is the ellipsometer of PSA as an example, and the angle calibration method when rotating the polarizer is illustrated through specific steps, which can be divided into the following steps:

[0116] (1) Fix the vibration transmission direction of the polarizer in the ellipsometer. Since the ellipsometer of the rotating polarizer is more sensitive at certain polarizer angles, and the measurement accuracy is higher, it is possible to fix the polarizer with the known approximate transmission direction to an appropriate angle before measurement, For example, make the angle between the transmission direction of the polarizer and the incident surface of the light beam on the reference sample be 45°, that is, make the angle of the polarizer P=45°. In fact, due to the low accuracy of the polarizer's vibration transmission direction, coupled with operational errors, it is difficult for the polarizer's vibration transmission direction to be precise...

Embodiment 2

[0123] as figure 1 The shown structure is the ellipsometer of PSA as an example, and the angle calibration method of the rotating polarizer is illustrated through specific steps, including the following steps:

[0124] (1) Fix the vibration transmission direction of the analyzer in the ellipsometer. Since the ellipsometer of the rotating polarizer is more sensitive at certain angles of the analyzer, that is, the measurement accuracy is higher, the analyzer can be rotated to a suitable angle before the measurement fixed. For example, the angle between the transmission direction of the analyzer and the incident surface of the light beam on the reference sample is 22.5°, even if the angle of the analyzer is 22.5°. In fact, due to the low accuracy of the transmission direction of the polarizer, coupled with operational errors, it is difficult for the angle of the transmission direction of the polarizer to be precisely at this angle, but around this angle.

[0125] (2) Measure t...

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Abstract

The invention discloses a calibration method of a polarization angle and a light incidence angle of an ellipsometer in an ellipse polarization measuring system and belongs to the technical field of optical measuring devices. The calibration method includes fitting by a least square method according to the Fourier coefficient and referring to a relation expression of an optical coefficient of a sample and work parameters of the ellipsometer to acquire calibration values of the work parameters of the ellipsometer. System parameters including polarization directions of a polarizer and an analyzer and the light incidence angle in the ellipsometer can be calibrated by the method, calibration process is simple and accurate, measurement can be achieved directly without adjusting parts of a system after calibration, and accordingly the measurement process is simplified, and precision in measurement is increased.

Description

technical field [0001] The invention relates to the technical field of optical measuring instruments, in particular to a method for calibrating the polarization angle and light incident angle of an ellipsometer in an ellipsometer system. Background technique [0002] With the rapid development of the semiconductor industry, it is very important to use optical measurement technology to accurately measure the critical dimensions, spatial morphology and material properties of the three-dimensional structure formed by single-layer or multi-layer thin films on the wafer. In order to make the measurement results effective, the measurement used The system should be able to measure film thickness and / or film composition with high accuracy. The ellipsometry method used in the prior art obtains the characteristic parameters of the reference sample by measuring the polarization of the light reflected by the reference sample. Since the ellipsometry method has the advantages of high sens...

Claims

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Application Information

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IPC IPC(8): G01N21/21
Inventor 徐鹏刘涛王林梓刘健鹏李国光
Owner INST OF MICROELECTRONICS CHINESE ACAD OF SCI
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