Korea Research Institute of Standards and Science

Chu-Shik Kang

Jong-Ahn Kim

Jae-Wan Kim

Tae-Bong Eom

Jong-Han Jin

Jae Wan Kim

Jong Ahn Kim

Jong Han Jin

Provided are a thickness measuring apparatus and a thickness measuring method. The thickness measuring method includes irradiating a first laser beam of a first wavelength &#x3bb;to a transparent substrate and measuring intensity of the first laser beam transmitting through the transparent substrate; irradiating a second laser beam of a second wavelength &#x3bb;to the transparent substrate and measuring intensity of the second laser beam transmitting through the transparent substrate; and extracting a rotation angle on a Lissajous graph using the first and second laser beams transmitting through the transparent substrate. A phase difference between adjacent rays by multiple internal reflection of the first laser beam and a phase difference between adjacent rays by multiple internal reflection of the second laser beam is maintained at &#x3c0;/2.

Thickness measuring apparatus and thickness measuring method

Provided are an absolute position measurement method, an absolute position measurement apparatus, and a scale. The scale includes a scale pattern formed by replacing repeatedly arranged pseudo-random-codes with a sequence of a linear feedback shift register of N stages using a first symbol with first width representing a first state and a second symbol with second width representing a second state. The first is divided into two or more first symbol areas of different structures, and the second symbol is divided into two or more second symbol areas of different structures. There is at least one overlap area in which the first symbol and the second symbol overlap each other to have the same structure.

Absolute position measurement method, absolute position measurement apparatus and scale

The present invention pertains to a device and a method for measuring a via hole of a silicon wafer, wherein it is possible to precisely measure the depth of the via hole without damaging the wafer. Broadband infrared light is radiated to a silicon wafer which has a superior light transmission property, so that the depth of the via hole may be measured from the light which is reflected from each boundary surface of the wafer and the interference signal of reference light. The via hole measuring device according to the present invention includes: a light source unit for generating broadband infrared light; and an interferometer for radiating the light generated from the light source unit to a silicon wafer, so as to measure the depth of a via hole formed on the wafer according to the spectrum period of the interference signal of the light, which is reflected from the silicon wafer.

Device and method for measuring via hole of silicon wafer

A frequency-stabilized laser apparatus and a method for stabilizing the frequency of a laser are disclosed. A semiconductor laser emits a beam. An external reflector has a resonance frequency and feeds back the emitted beam to the semiconductor laser if the frequency of the emitted beam is equal to the resonance frequency. An interference signal generator generates an interference signal for detecting the wavelength of the emitted beam and a controller detects the wavelength of the beam from the generated interference signal. According to the frequency-stabilized laser apparatus and the method for stabilizing the frequency of the laser, it is possible to stabilize the frequency of the beam emitted from the semiconductor laser and output the beam having the stable frequency for a long period of time.

Apparatus and method for stabilizing frequency of laser

A shape measurement apparatus and method using a laser interferometer are disclosed. The shape measurement apparatus includes a plurality of laser devices, which generate beams, emit a beam of a specific frequency from among the generated beams, and output interference signals for detecting wavelengths of the generated beams, and a controller for detecting the wavelengths of the generated beams from the outputted interference signals, and controlling the laser devices on the basis of the detected wavelengths. The optical unit projects the beam of the laser device on a target object, and generates an interference pattern of the object. Several shutters are closed and opened. If the shutters are closed, they prevent the beam of each laser device to be projected on the optical unit. An image pickup unit captures the interference pattern.

Growing community of inventors

Daejeon, South Korea

Chu-Shik Kang