Kodak reports to laboratories on: h o w to carve a f a n c y design on a microscopic bit of semi-conductor, , · making one's point v i v i d l y in a learned journal . . . a leap-year proposal
Here's how
Here is how to carve a microscopic bit of a semi-conductor like germa nium or silicon into as intricate a structure as you need to beat a complex vacuum tube at its own game: Draw up the pattern nice and big with India ink. Photograph it down to a stencil of desired size with a good lens (like a Kodak Process Ektar Lens) on a virtually grainless, all-or-none material (like Kodalith Ortho Film or, for really tiny work, a Kodak High Resolution Plate). Saw out a blank of the semi conductor crystal. L a p and polish it, finishing up with 0.5/z grid-size diamond paste. Etch off the remain ing few microns of work-strained layer. Wash in trichloroethylene, rinse in distilled water, and dry. Avoiding daylight or u' xaviolet, filter a little Kodak Photo Resist. With it, coat the polished semi conductor surface thinly. Dry under a heat lamp. Hold the stencil tight against the semi-conductor by vac uum. Expose to an arc lamp. Im merse in Kodak Photo Resist De veloper. Take out. Put on a few drops of Kodak Photo Resist Dye to make the developed image visi ble. Hold under a stream of tepid distilled water to wash away the resist where the dark portions of the stencil shielded it. Pull up the window shades. Blot off the surface moisture. Inspect the pattern with a microscope. If OK, bake for a few minutes t o harden the resist. Let an etchant suitable to the specific semi conductor remove it t o any required
depth in those areas where there is no resist left to resist. Over the whole, deposit a metal electrically, chemically, or by evap oration. Immerse in 2-Ethoxyethyl Acetate* for 10 minutes and gently swab. This solvent, undeterred by the overlying metal film, removes the remaining resist. There's your little triumph in ap plied solid state physics, complete with electrodes. This is basically Bell Telephone Lab oratories* idea, not ours. All we did was to suggest Kodak Photo Resist. Ap parently it was a good suggestion. Any body else who wants any suggestions about the Kodak products involved can write Eastman Kodak Company, Graphic Reproduction Division, Rochester 4, Ν. Υ.
Cut-rate color
A beautiful photograph of Casfilleja linearifolia
in f u l l color might have
been printed in this space.
A set of four printing plates would have been required—magenta (known to printers as "red"), cyan (known to printers as "blue"), yel low, and black. Arrangements would have had to be made for the page to go through four impressions under exacting conditions of regis ter and inking. We could have af forded it and so could almost any other firm listed on the New York Stock Exchange. To a certain national wildflower society, however, which does have a beautiful color transparency of Castilleja linearifolia to reproduce in its bulletin, this order of expenditure is enough to chew its whole publica tion budget into shreds. Such figures *Available as Eastman Organic Chemi cal No. P2378 at $2.05 for 1 kg. from our division, Distillation Products In dustries, Rochester 3, Ν. Υ.
have scared off many other societies and publishers of periodicals and books aimed at smallish audiences. Very well, we have devised a cutrate color printing method. It is in tended for press runs of not much more than 2500 copies. It dispenses with the black plate, depending on overprinted heavy inking for render ing dark areas. It permits none of the laborious hand work that's back of the exquisite effects achieved in some color advertisements and none of the color correction by electronic computing circuitry, used for edito rial color illustrations in some mass magazines. It would hold down the soaring flight of an advertising art director's creative imagination. But, by George, it's color printing, and it might be just the ticket for the scientist with a few Kodachrome or Ektachrome slides that drive home the whole point he wants to make. Matter of fact, it was him we devel oped the process for. Eastman Kodak Company, Graphic Reproduction Division, Rochester 4, Ν. Y., can supply the names of some printers who know all about the "3-color short-run'''' process. It is all right to carry on in print this way about the 3500-odd Eastman Organic Chemicals, we suppose, but we would much rather clasp your hand in person while stealing a look from the corner of our eye at the registration badge you wear. This we propose to do at Booth 74 of the Pittsburgh Conference on Analyti cal Chemistry at the Hotel William Penn in that city some time between 10 a.m., Tuesday, February 28 and 6 p.m., Friday, March 2. What about Wednesday? You don't get too many chances in a lifetime t o make a friend on the 29th of Febru ary. Ifs a date, then. Any questions about organic reagents and the like been troubling you ? Price quoted is subject to change without notice.
This is one of α series of reports on t h e many products a n d services with which t h e Eastman Kodak Company a n d its divisions a r e . . . $6fWflfl
laboratories everywhere
famm FEB.
2 0,
1956
C&EN
815
