불규칙한 위상과 진폭을 갖는 진동자를 이용한 반사형 디지털 홀로그래피에 관한 연구

Abstract

Digital hologram technology is a method of acquiring hologram data of an object to be measured in real time using a moving picture recording device such as a CCD, starting from the existing hologram technology, and acquiring 3D data of the object to be measured by a method of reproducing a numerical 3D image. Holography can be considered suitable as a technology capable of recording and reproducing optical wave fields. More specifically, holography is a method of recording and reproducing information on a 3D object based on interference and diffraction between an object beam diffusely reflected from a 3D object and a reference beam used for recording and reproduction. It is widely used in various optical applications. In fact, the term holography or hologram is used as a collective term for all methods of physically reconstructing a three-dimensional object by light waves. Holographic display technology has been steadily developed since the 1960s. Research on 3D displays using holograms has been continuously researched for the past 60 years according to the technological belief that a hologram of a method of extracting and restoring light information will provide the ultimate solution for 3D video display. In particular, in recent years, with the rapid development of digital technology, research on a 3D hologram display of a method of extracting 3D hologram information of an object in the form of a digital signal and processing and restoring it has been actively conducted. However, research on digital holograms for 3D displays is a method of synthesizing and restoring computer generated holograms of virtual objects, such as 3D animation, and studies on computer generated holograms and hologram restoration display devices have become mainstream. However, for a complete loop of a 3D image system using holograms, it is essential to extract hologram information of an actual object in the form of a digital signal. In this paper, a reflective digital holography system based on a Michelson interferometer using He-Ne Laser, Spatial filter, Collimating lens, Iris, Beam Splitter (BS), CMOS Camera, and Mirror to measure a specimen of reflective material. First, in the measurement of the resolution target using the oscillator phase shift reflection type digital holography, the measurement is performed on an arbitrary part to measure the step difference for the pattern. Second, the measurement of the photolithographic product using the oscillator phase shift reflective digital holography is a frame to check the measurement result of the reflective digital holography on the relationship between the intensity of vibration and the frame to measure the level of the electrode portion deposited on the Chrome substrate. Conditions were measured for three conditions of 20, 40, and 60, and vibration conditions were measured for five conditions of vibration levels 0, 1, 2, 3, and 4 displayed on the controller. This equipment is universally used to secure the reliability of the measurement results of photolithographic products using the oscillator phase shift reflective digital holography, and can measure non-destructively by scanning the measurement object directly with the probe tip for the object to be measured. It compared with the measurement result of phosphorus AFM.