N K Technology Ltd

Thaddeus J Wilson

Marc T Aho

Jeff Roberts

A spatial photomask flipper provides up to four access gates for an unloading of a clamped photomask after its reorientation along a single photomask transfer axis. The clamping frames holding the photomask are secured by a locking control cam that prevents their inadvertent opening in any other but the two main flip orientations. The flipper is part of an automated system including a digital camera and an image recognition algorithm that interpret an arbitrary initial photomask loading orientation from a circumferential photomask identification number. An eventual pellicle on the photomask may be also automatically detected via a pellicle detection sensor. Alternately, the digital camera may be employed for pellicle detection together with a pellicle detection algorithm that processes the digital image for well known components of the pellicle such as the pellicle frame.

Automated spatial flipping apparatus and system for photomasks and photomasks with pellicles

A compact multiple diameter wafer testing device with a footprint of about 33 by 34 inches features on-chuck wafer calibration and integrated cassette-chuck transfer. It includes a five axes wafer handling system, a quick exchange chuck and a fixed through beam sensor fixed. Two of the five axes are provided by an X-Y stage, a third axis is provided by a rotary stage on top of the X-Y stage, a fourth axis belongs to a rotating effector and a fifth axis is provided by motion controlled pin lifters all combined with the X-Y stage. The quick exchange chuck may be easily changed for different wafer diameters and also calibrated by the through beam sensor. The through beam sensor provides on-chuck position calibration of the chucked wafers in conjunction with the X-Y stage and rotary stage. The compact wafer testing device handles wafers between six and twelve inches diameter.

Compact multiple diameters wafer handling system with on-chuck wafer calibration and integrated cassette-chuck transfer

A pellicle correction factor is determined by comparing a first measurement of a reference photomask alone with a second measurement of that reference photomask through a reference pellicle protecting the mask layers of the photomask. A number of pellicle correction factors may be determined for different type pellicles and made accessible in pellicle correction factor lookup table of the system or supplied on a separate data storage medium. Raw Reflectance and/or Transmittance measurement data of a generic photomask through a generic pellicle is consecutively corrected for the measurement distorting effects of that pellicle by applying a matching one of the previously determined pellicle correction factors. The pellicle correction factor is preferably an attenuation signature across a predetermined measurement irradiation spectrum.

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Sunnyvale, CA, United States of America

Thaddeus J Wilson