Patent ID: 11935227
Assignee: DISCO CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC G  H | IPC G

Claim 0:
1. A notch detecting method for detecting a notch defined in an outer circumferential portion of a disk-shaped wafer as representing a crystal orientation of the wafer, comprising:
a placing step of placing the wafer on a rotary table and positioning a portion of the outer circumferential portion of the wafer in an image capturing area of a camera;
an image capturing step of capturing a plurality of images of the wafer with the camera while the rotary table is rotating, thereby 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 on a basis of the acquired image;
a hypothetical circle calculating step of calculating a hypothetical circle that approximates the contour of the wafer, on a basis of the coordinates of 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 on a basis of a distance between the hypothetical circle and the contour of the wafer along radial directions of the wafer; and
a first notch determining step of determining whether the irregularly shaped area is a notch or not on a basis of a distance between the hypothetical circle and a tip end of the irregularly shaped area along the radial directions of the wafer.