Patent ID: 7183783

Claim:
A wafer prober for testing a plurality of semiconductor chips formed on a wafer, each chip having a plurality of bonding pads, each pad having a pad contact area, comprising: a probe card having at least two probes arranged such that said probes can simultaneously contact at least two of said bonding pads; a first positioning means for changing, in response to a control signal, a relative position between said probe card and said wafer in directions normal to a face of said wafer, between a position at which said probes touch said bonding pads and a position at which said probes are separated from said bonding pads; a second positioning means for changing, in response to the control signal, the relative position between said probe card and said wafer, in directions parallel to said face; and a control unit having means for measuring electrical characteristics between pads contacted by said probes, contact identifying means for identifying if a pad has been contacted by said probe, and means for generating a sequence of said control signal such that said first positioning means, said second positioning means and said means for measuring carry out a succession of measurement cycles, where in at least one of the measurement cycles said first positioning means seperate said probes of said probe card from said bonding pads, said second positioning means subsequently changing a positional relation between said probe card and said wafer to a position wherein at least one of said probes is aligned above a contact location within the contact area of a target pad of said bonding pads, wherein said contact location is based on a starting predetermined standard location and an offset, wherein said offset is based, at least in part, on whether or not said contact identifying means identifies that said target pad has been previously contacted by any of said probes, said first positioning means subsequently bringing said at least two of said probes of said probe card into contact with said at least two predetermined pads of said bonding pads, including said at least one of said probes contacting said target pad at said contact location, said measuring means measuring electric characteristics between designated pads of said bonding pads.