Patent ID: 9651502
Date: 2017-05-16
CPC Classifications: G01N,G01R,H01L,H04N,Y02E

Claim:
1. An inspection method comprising: directing light at a first surface of a wafer along a first direction, the wafer having the first surface and a second surface, wherein the first surface and the second surface are two outward facing surfaces of the wafer and are each substantially parallel to an x-y plane, wherein the second surface is on an opposite side of the wafer as the first surface; receiving light transmitted through the first surface of the wafer and emanating from the second surface of the wafer substantially along the first direction for obtaining a first image of the second surface therefrom, the wafer having a crack formed therein, the first image showing the crack as having a first set of line widths; directing light at the first surface of the wafer along a second direction; receiving light transmitted through the first surface of the wafer and emanating from the second surface of the wafer substantially along the second direction for obtaining a second image of the first surface therefrom, the orthographic projection of the second direction on the x-y plane being substantially perpendicular to the orthographic projection of the first direction on the x-y plane, wherein the second image captures substantially the same surface area of the wafer as the first image, and shows the crack as having a second set of line widths different from the first set of line widths in the first image; and constructing a third image from the first image and second image such that the third image shows the crack as having a third set of line widths, wherein the third image is substantially processable for inspecting the crack in the wafer.