Automated wafer inspection

摘要

In semiconductor fabrication processes, one or more wafers are often exposed to processes such as chemical vapor deposition to form semiconductor components thereupon. Often, some of the wafers exhibit flaws due to contamination or processing errors occurring before, during, or after component formation. Inspection of the wafers is often performed by direct visual inspection of humans, which is prone to errors due to flaws that are too small to view directly; to particles naturally arising in the human eye; and to fatigue caused by inspection of large numbers of wafers. Presented herein are inspection techniques involving positioning the wafer in a dark chamber exposing the surface of the wafer to a light source at a first angle, and capturing with a camera an image of the light source reflected from the surface of the wafer at a second angle. Wafers identified as exhibiting flaws are removed from the wafer set.

主权项

1. A method, comprising:
positioning a wafer in a dark chamber; illuminating a surface of the wafer with a light source oriented toward the wafer at a first angle; capturing with a camera an image of light reflected from the surface of the wafer at a second angle; evaluating the image captured by the camera, comprising:
identifying at least one flaw in the wafer using the image; andcomparing a flaw count, corresponding to a number of flaws identified in the wafer using the image, to a flaw count threshold; performing a first action when the flaw count is less than the flaw count threshold; and performing a second action different than the first action when the flaw count is more than the flaw count threshold.