Hamamatsu-photonics K.k.

Teruo Takahashi

Tadashi Maruno

Eiji Toda

Takafumi Higuchi

Mao Nakajima

Motoyuki Watanabe

Hidenori Takahashi

Tohru Shimizu

A photon counting device includes a plurality of pixels each including a photoelectric conversion element configured to convert input light to charge, and an amplifier configured to amplify the charge converted by the photoelectric conversion element and convert the charge to a voltage, an A/D converter configured to convert the voltage output from the amplifier of each of the plurality of pixels to a digital value and output the digital value, a correction unit configured to correct the digital value output from the A/D converter so that an influence of a variation in a gain and an offset value among the plurality of pixels is curbed, a calculation unit configured to output a summed value obtained by summing the corrected digital values corresponding to at least two pixels, and a conversion unit configured to convert the summed value output from the calculation unit to a number of photons.

Photon counting device and photon counting method

A photon counting device includes a plurality of pixels each including a photoelectric conversion element configured to convert input light to charge, and an amplifier configured to amplify the charge converted by the photoelectric conversion element and convert the charge to a voltage, an A/D converter configured to convert the voltages output from the amplifiers of the plurality of pixels to digital values; and a conversion unit configured to convert the digital value output from the A/D converter to the number of photons by referring to reference data, for each of the plurality of pixels, and the reference data is created based on a gain and an offset value for each of the plurality of pixels.

At each measurement time, measurement light is supplied from a measurement light source, and interference light obtained when reflected light from a semiconductor wafer W and reference light from a reference light generating sectionare coupled is detected by a photodetector. A thickness calculating sectionobtains a light intensity distribution representing the correlation between the light intensity of the interference light and the reference optical path length, selects a wafer upper surface peak and wafer lower surface peak from a plurality of light intensity peaks in the light intensity distribution using a predetermined selection criterion, and calculates the thickness of the semiconductor wafer W from the optical path length difference between the light intensity peaks. With this arrangement, a thickness measuring apparatus and thickness measuring method capable of measuring the thickness of a semiconductor wafer during execution of wet etching independently of the presence of an etchant, and a wet etching apparatus and wet etching method using the thickness measuring apparatus and method are implemented.

Thickness measuring apparatus, thickness measuring method, and wet etching apparatus and wet etching method utilizing them

At each measurement time, reflected light from a semiconductor wafer W or the like by measurement light from a measurement light source is coupled to reference light from a reference light generating section and interference light is detected by a photodetector A raw thickness value calculating section selects two light intensity peaks corresponding to the upper and lower surfaces of the wafer W from a light intensity distribution between an interference light intensity and a reference optical path length and calculates a raw thickness value. A statistical thickness value calculating section executes statistical processing including data sorting, determination whether the raw thickness value falls within an allowable numerical value range, and determination of a thickness change line, thereby obtaining a statistical thickness value. With this arrangement, a thickness measuring apparatus and thickness measuring method capable of measuring the thickness of a semiconductor wafer during execution of wet etching independently of the presence of an etchant, and a wet etching apparatus and wet etching method using the thickness measuring apparatus and method are implemented.

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Hamamatsu, Japan

Teruo Takahashi