Disco Corporation

Yasukuni Nomura

Shinji Yoshida

Koji Hashimoto

A measuring method includes storing thickness data of each of chips held on a holding surface of a holding table, the thickness data being obtained by measurement of thicknesses of portions of the chip at a plurality of measurement points and representing the thicknesses measured at the measurement points in association with positions of the measurement points in a predetermined plane corresponding to a reverse side of the wafer, storing positions of central lines of dividing grooves in the predetermined plane in captured images of reverse sides of the chips, setting, in a periphery of each of the chips, a thickness data unreferencing zone including measurement points where the thickness data will not be referenced in calculating the thickness of the chip, and calculating, for each of the chips, an average value of thicknesses at the measurement points except for the measurement points included in the thickness data unreferencing zone.

Measuring method

A notch detecting method for detecting a notch defined in an outer circumferential portion of a wafer includes a placing step of placing the wafer on a rotary table, an image capturing step of acquiring an image of the outer circumferential portion of the wafer, a contour data acquiring step of acquiring contour data including coordinates of a contour of the wafer, a hypothetical circle calculating step of calculating a hypothetical circle that approximates the contour of the wafer, an irregularly shaped area determining step of determining whether an irregularly shaped area exists in the outer circumferential portion of the wafer or not, and a first notch determining step of determining whether the irregularly shaped area is the notch or not.

Notch detecting method

A micro camera is placed in an appropriate image capturing position therefor on the basis of a center-to-center distance depending on a rotational angle of a holding table. Even in the case where the center Cof a holding surface and the center Cof a wafer are displaced out of alignment with each other, allowing a position in X-axis directions of an outer circumference of the wafer to vary as the holding table rotates, a control unit can make an image capturing range of the micro camera follow the varying position of the outer circumference of the wafer. Therefore, the image capturing range of the micro camera can be determined with ease. Both a surface of the wafer and the outer circumference of the wafer can be inspected simply when two cameras are moved along the X-axis directions by a single X-axis moving mechanism.

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Tokyo, Japan

Yasukuni Nomura