Method and apparatus for inspection of patterned semiconductor wafers

Abstract

Novel method and apparatus are disclosed for inspecting a wafer surface to detect the presence thereon of exposed conductive material, particularly for determining the integrity of contact holes and vias, in semiconductor wafer manufacturing. The method comprises the steps of irradiating a spot of the wafer surface with a beam having a wavelength sufficiently shorter than the working function of the metal, such as deep UV light beam, collecting the electrons released by the irradiated wafer, generating an electrical signal that is a function of the collected electrons, and inspecting the signal to determine whether the contact holes or vias within the irradiated wafer spot are open. The apparatus comprises a vacuum chamber having therein a stage and chuck for supporting the wafer. An illumination source generates irradiating energy which is formed into a beam using appropriate optics so as to obtain the desired beam spot of the wafer's surface. an electron detector collects electrons released from the wafer surface and sends a corresponding signal to a processor for processing the signal to determine whether the metal at the bottom of the hole is exposed. Optionally, the light scattered by the wafer is detected by detectors arranged around the illuminating beam.

Dependencies are inferred from the claim text.