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Optical Coatings 251

TABLE 11.2 Resolution and Accuracy of Reticle Producing Techniques
Finest line Dimensional Minimum figure
Method width, in repeatability, in height, in
Scribing 0.00001 0.00001
Etch (and fill) 0.0002–0.0004 0.0001 0.004
Photo-resist
(evaporated metal) 0.0001–0.0002 0.00005 0.002
Glue silver 0.00003–0.0002 0.00005–0.0005 0.002
Black print 0.001 0.0001 0.005
Emulsion 0.00005–0.0001 0.00005 0.001

photosensitive material is opaque. The clear areas are free of emul-
sion. Glue silver reticles are fragile but capable of very high resolu-
tion of detail. The black-print process is more durable. Occasionally
an extremely high resolution photographic emulsion is used for a
reticle pattern; however, the presence of emulsion in the clear areas
of the pattern is ordinarily a drawback.
Table 11.2 indicates the resolution and accuracy possible with
these techniques. These figures represent the highest level of qual-
ity that reticle manufacturers are capable of at the present time; if
cost is a factor, one is well advised to lower one’s requirements an
order of magnitude or so below the levels indicated here.

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