Method of back cutting silicon wafers during a dicing procedure
AssigneeXerox Corporation
InventorsLawrence H. Herko, David J. Collins, Kevin A. Lindamood
Life of this patent
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Abstract
An improved back cut method is provided in a dicing procedure for separating a plurality of printheads formed in a silicon wafer. The wafer has alignment fiducial marks formed within a composite wafer. Infrared light is directed into the wafer and is reflected back through the wafer from the fiducial marks. The reflected light is detected by a CCD camera mounted on a dicing saw. The fiducial coordinates are stored in memory and displayed so that the dicing saw can be aligned with regard to the alignment marks. A back cut operation is enabled so that the saw partially cuts through the composite wafer. A subsequent dicing step separates individual printheads from the wafer.
Claims6
A method of fabricating a plurality of printheads for use in an ink jet printing machine comprising the steps of:
- aligning and bonding an upper silicon substrate defining a plurality of ink channel plates with a lower silicon substrate defining a plurality of heater plates, one side of the bonded substrate defining a front nozzle face, the plurality of bonded channel plates and heater plates comprising a plurality of printheads integrally formed on a silicon wafer,
- forming opaque fiducial alignment marks within the wafer,
- generating an infrared (IR) component of light,
- directing the IR component of light through the wafer so that light from the fiducial marks is reflected back through the silicon wafer,
- sensing the light reflected from the fiducial marks and generating signals which are stored corresponding to the coordinates of said fiducial marks,
- aligning a dicing saw with the stored coordinates,
- performing a series of back cut dicing operations using the detected alignment marks as a dicing saw reference and
- separating the wafer into a plurality of printheads.
A method for performing an operation with a workpiece on one surface of a silicon wafer using light reflected from fiducial marks representing coordinate positions within the wafer pair to align the workpiece, the steps comprising:
- directing infrared light into the wafer in a reflection mode wherein light is reflected from said fiducial marks,
- positioning a CCD camera in a position to intercept the IR light reflected from the fiducial marks,
- storing the coordinate information reproduced by the detected fiducial marks in CCD camera memory and
- generating output signals from said CCD camera corresponding to said stored fiducial mark signals to operate said workpiece to perform an operation on the wafer based on the coordinate locations.
Dependencies are inferred from the claim text.