Masking plates 52, fabricated of metal, are positioned across aperture 46 of plate 40 an equal distance from {HEAD ~ the center} of {TAIL ~ the aperture} to prevent deposition of charge over a ringed shaped portion of the wafer 
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Masking plates 52 , fabricated of metal , are positioned across aperture 46 of plate 40 an equal distance from { HEAD ~ the center } of { TAIL ~ the aperture } to prevent deposition of charge over a ringed shaped portion of the wafer
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH