Other

Tokyo Institute of Technology

Toray Engineering Company, Limited

Hidemitsu Ogawa

Katsuichi Kitagawa

Kazuyoshi Suzuki

Masashi Sugiyama

Akira Hirabayashi

A reference plane is arranged in a posture obliquely tilted at an optional angle relative to a traveling direction of a light-beam, so that an interference fringe is generated from the reflected light-beams which are reflected from a target plane and the reference plane and, then, return on a single optical path. An image of the interference fringe is taken by a CCD camera to acquire intensity value data of each pixel. A phase of an interference fringe waveform is obtained for each pixel by a CPU by fitting the intensity value data to a model equation expressing the interference fringe waveform, where the intensity value data contain that of each pixel and those of the pixels in the vicinity of the relevant pixel, on assumption that DC components, AC amplitudes and phases of the interference fringe waveforms are respectively constant in the vicinity of the relevant pixel. The obtained phase is converted into a height to measure a surface profile.

Method for measuring surface profile, and apparatus using the same

A surface profile measuring apparatus for measuring rugged profiles of object surfaces includes a white light source, a varying device for varying a relative distance between an object surface and a reference surface, a frequency band limiting device for limiting the frequency band of white light to a particular frequency band, an image pickup device for picking up an image of the object surface, a sampling device for successively acquiring intensity values of interference light corresponding to varying interference fringes, from a particular location at sampling intervals corresponding to a bandwidth of the particular frequency band, a storage device for storing a group of interference light intensity values acquired, and a computing device for estimating characteristic functions from the group of interference light intensity values stored, and determining a height in the particular location based on a peak position of the characteristic functions.

Surface profile measuring method and apparatus

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Otsu, Japan

Hidemitsu Ogawa