Method for transporting and testing wafers
OwnerDavid Chenginventor
Life of this patent
Estimating the term…
Abstract
A method and apparatus for handling wafers. A wafer pick moves along a horizontal x-axis to unload a wafer from a cassette and position the wafer over a chuck. The chuck moves upwardly along a z-axis perpendicular to the surface of the wafer and lifts the wafer off the pick. The pick retracts through a slot in the chuck and a test probe moves along the x-axis to position itself over the wafer and chuck with reference to a calculated wafer center. The chuck then moves upwardly to engage the surface of the wafer with the probe. Wafer characteristics are tested at several test points located on a circle on the surface of the wafer by repeatedly lowering the chuck, rotating the chuck by a small amount, and raising the chuck to engage the wafer with the probe. The probe is then positioned to test another circle of points.
Claims24
A method for testing a surface of a planar workpiece comprising:
- a) placing a workpiece on a support surface such that a test surface of said workpiece faces upwardly;
- b) moving a test head to a position above said workpiece, said test head being moved in an x-direction along an x-axis parallel to said test surface of said workpiece;
- c) moving said support surface upwardly to cause said test surface to engage said test head positioned above said workpiece;
- d) moving said support surface downwardly to disengage said test head from said workpiece;
- e) translating said test head parallel to the plane of said workpiece;
- and
- f) repeating steps c and d.
A method for testing a surface of a planar workpiece comprising:
- a) placing a workpiece on a support surface of a chuck such that a test surface of said workpiece faces upwardly, said step of placing being accomplished with a handler movable only along an x-axis parallel to an x-y plane of said test surface of said workpiece;
- b) moving a test head along an x-axis until said test head is positioned above said workpiece;
- c) moving said chuck upwardly along a z-axis to cause said test surface to engage said test head;
- d) testing a property of said workpiece using said test head;
- e) moving said chuck downwardly to disengage said test head from said workpiece;
- f) translating said test head in a plane parallel to said x-y plane;
- g) maintaining said chuck at a stationary position with respect to translation in a plane parallel to said x-y plane during said steps of moving said chuck upwardly and downwardly, said step of testing, and said step of translating said test head;
- and
- h) repeating said moving said chuck upwardly, said testing, and said moving said chuck downwardly to engage said test head at a different location on said test surface of said workpiece.
A method for handling and testing a planar workpiece comprising the steps of:
- a) placing a workpiece on a support surface such that a test surface of said workpiece faces upwardly;
- b) translating a test head in an x-y plane until said test head is positioned above said workpiece;
- c) moving said support upwardly to cause a test point on said test surface to engage said test head positioned above said workpiece so that testing of said workpiece can begin;
- d) moving said support downwardly to disengage said test head from said workpiece when testing at said test point is complete;
- and
- e) repeating steps c and d for a plurality of different test points on said test surface, wherein at least two of said different test points are at a different distance from a center of rotation of said support, and wherein said support remains stationary in said x-y plane with respect to translation in a plane parallel to said x-y plane during the testing of said different test points.
Dependencies are inferred from the claim text.