The Alignment Method for Linear Scale Projection Lithography Based on CCD Image Analysis

Abstract

This paper presents a method to improve the alignment accuracy of mask in linear scale projection lithography, in which the adjacent pixel gray square variance method of CCD image is used to find the best position of the focal length of the motherboard and then realize the alignment of the focal plane. Two image positions in the focal plane from the CCD are compared the traits overlap through the image splicing principle, and to establish the correction of four typical errors on the basis of the whole grating errors. At the same time, using the rotation error of the mask to summarize Grayscale Variation Function of CCD Image, and threshold functions are used to express the factors including wave crests of the amplitude, period error and phase error, which govern the rotation accuracy and weight alignment accuracy expression of the four error factors is established. In the experiment, it is finally corrected the slope of the mask and be adjusted the same direction of the slide plate with the help of dual-frequency laser interferometer, the influence of alignment error on lithography accuracy was discussed and verified in the static case and the CCD maximum resolution pixel corresponds to 0.1 μm, the accuracy of scale is 0.79 μm in only 200 mm measurement range.

Displacement Measurement Method Based on the Rotating Paraboloid Array

“…On the one hand, non-optical displacement measurement methods include capacitance measurement and inductance measurement [13,14]. On the other hand, laser triangulation [15], optical levers [16], grating displacement measurement [17], fiber displacement measurement [18], and laser interferometry [19] belong to the optical displacement measurement methods. The capacitance measurement method can achieve high measurement resolution, but its range is shorter, generally less than 1 mm [20].…”

Influence of Exposure Energy Control for High Voltage Pulsed Xenon Lamp on the Lithography Accuracy of Linear Grating

“…The pulsed xenon lamp power control system is the main factor affecting the energy release time [1][2][3]. In raster computing lithography, the static exposure of the lithographic threshold model is used to calculate the accuracy of the exposure energy on the grating fringe [4][5], such as the dynamic exposure energy lithography of the diffraction grating [6]. In this paper, the volt-ampere characteristics of pulsed xenon lamp are studied for the pulsed xenon lamp power supply circuit.…”

Alignment Method for Linear-Scale Projection Lithography Based on CCD Image Analysis

“…The alignment of grating lithography is characterized by uniform grating stripes and a certain length; therefore, a major technical problem arises when a lithography plate or mask exhibits a tilting or rotating phenomenon. Such an installation error will seriously affect the accuracy of the linear scale, and some related content has been explained at an international conference [ 1 ].…”