Aloysius Thomas Pfeiffer

40229270, May 10, 1977

Jun 30, 1975

5/592001

Aloysius T. Pfeiffer - Peekskill NY
Lubomyr T. Romankiw - Briarcliff NY

International Business Machines Corporation - Yorktown Heights NY

B05D 306

427 43

A method of constructing a relatively thick, self-supporting mask suitable for electron beam projection processes. Thickness is achieved by multiple steps of coating with resist, exposure and development. Either positive or negative resist may be used for second and subsequent coatings. Second and subsequent exposures are directed through the first relatively thin mask formed and through the substrate to eliminate critical alignment of subsequent masks. When desired thickness is achieved an even thicker frame may be fabricated for support purposes and the mask may then be lifted off the substrate on which it had rested during the fabrication steps. When positive resist is employed, the resist remaining after development is baked on to give added structural strength to the mask. This baked resist can be coated with an additional layer of metal by evaporation or sputtering to give greater mechanical strength. When negative resist is employed, the portions of the resist protected by the relatively thin previously formed mask are removed and additional material is plated to increase the thickness and strength of the mask.

42810574, Jul 28, 1981

Feb 7, 1977

5/766308

Eugene E. Castellani - Putnam Valley NY
Ian M. Croll - Pleasantville NY
Aloysius T. Pfeiffer - Peekskill NY
Lubomyr T. Romankiw - Briarcliff Manor NY

International Business Machines Corporation - Armonk NY

G03C 500
G03C 176
G03C 186
G03C 194

430270

Resist is applied to a surface with a syringe, or other suitable dropper, equipped with a millipore filter to remove contaminants. The surface is completely flooded with resist. Resist is allowed to remain on the surface of the evaporated metal for a period of time prior to spin coating. Allowing resist to remain on the surface prior to coating produces a uniform film. For a 2 micron thick uniform resist coating, a minimum of 15 seconds is allowed prior to spinning while in the case of a 4 micron thick resist coating a much longer period is allowed. For the application of a 2 micron film, the resist material after partial drying for approximately 15 seconds is spun at 2000 rpm for 30 seconds. In order to apply a 5 micron thick resist film, resist is spun at 2000 rpm for 30 seconds after partial drying for approximately 10 minutes.

43159850, Feb 16, 1982

Dec 28, 1977

5/865344

Eugene E. Castellani - Putnam Valley NY
Ian M. Croll - Pleasantville NY
Aloysius T. Pfeiffer - Peekskill NY
Lubomyr T. Romankiw - Briarcliff Manor NY

International Business Machines Corporation - Armonk NY

G03C 500
G03C 176

430314

A method is disclosed for the production of thick and smooth layers of photoresist on the order of 2-15 microns thick. The substrate is flooded with resist as in the standard spin resist method, but instead of following the flooding step with spinning as usual, the second step is to provide a drying time for the flooded resist. Then at the end of the measured drying time, the resist is spun as usual. This can be used to produce fine line closely spaced circuitry in which the thickness of the lines in proportion to their width, or their aspect ratio, is large. Aspect ratios greater than 0. 4 and as high as 1. 5 are contemplated by the invention.

40802671, Mar 21, 1978

Dec 29, 1975

5/645108

Eugene E. Castellani - Putnam Valley NY
Patrick M. McCaffrey - Mahopac Falls NY
Aloysius T. Pfeiffer - Peekskill NY
Lubomyr T. Romankiw - Briarcliff Manor NY

International Business Machines Corporation - Armonk NY

C25D 502
C25D 108
C25D 120

204 15

A method of constructing a relatively thick, self-supporting mask suitable for electron beam projection processes. Thickness is achieved by multiple steps of coating with resist, exposure, development and plating. First an intermediate or lift off layer is deposited on a substrate. A plating or a cathode layer may then be deposited. Resist is then applied. A first mask layer comprises metal plated in accordance with the first pattern. For the second exposure a geometrically similar pattern is employed to generate larger apertures. Thus, if the first mask layer has 0. 20 mil apertures, the second layer might have corresponding 0. 21 mil to 0. 22 mil apertures. For initial mask patterns of about 2 mil the second layer might be 2. 02 mils. If desired, a third exposure can be employed with a third pattern, similar to the first two, but having larger apertures (by 0. 02 to 0. 03 mils) than the second pattern.