At&t Bell Laboratories

Lucent Technologies Inc.

At+t Corp.

Steven D Berger

James Alexander Liddle

John M Gibson

George Patrick Watson

William Devore

Marvin Leventhal

The invention is directed to a method and apparatus of projection lithography in which the contrast introduced into a radiation sensitive material caused by the proximity effect is effectively removed in a single exposure. Patterned radiation is transmitted through a lens system with at least one lens and a back focal plane filter. The back focal plane filter has at least two apertures, an image aperture and a proximity effect correction aperture. Patterned radiation is transmitted through the image aperture and introduces the desired image into the energy sensitive resist material. A portion of the inverse pattern radiation is transmitted through the proximity effect correction aperture and onto the energy sensitive resist material to effectively remove the contrast therein caused by the proximity effect.

Projection lithography apparatus

Process for device fabrication using projection lithography and an

Projection lithographic systems relying on radiant energy such as electrons and ion beams are substantially affected by the distance between the projection mask and the substrate. In particular, to avoid undesirable limitation of the obtainable resolution, this distance should be a meter or less.

Processes for electron lithography

Fabrication of 0.25 gm design rule or smaller devices on chips, that may attain levels of 256 megabit or higher depends upon lithographic patterning by use of accelerated charged particle beams. Fabrication is expedited by acceleration values resulting in deBroglie wavelengths at least in order of magnitude smaller than such design rule to permit cost saving both in fabricating apparatus and resulting devices. Most importantly, such wavelength values permit significant variation in spatial angle of incidence of beam to wafer to permit both large instantaneous exposure areas and in temporal angle of incidence to expedite beam scanning as emitted from a fixed particle source.

Device fabrication entailing submicron imaging

Fabrication of sub-micron design rule integrated circuits entails imposition of patterning information, consisting of degree of scattering, on a projected scanning beam of accelerated electrons by means of a mask, imaging being dependent upon passage through a back focal plane filter including a plurality of apertures for selectively passing relatively unscattered electrons.

Sub-micron device fabrication using multiple aperture filter

It has been found that for a SCALPEL lithographic system thermal effects dictate that the acceleration voltage for the exposing electrons be maintained within a specific range. This range depends on a variety of factors but is generally in the 50 to 150 KeV region. Additionally, thermal considerations also dictate the method of scanning the mask to print an entire wafer.

Projection electron lithographic procedure

Fabrication of submicron design rule large scale integrated circuits depends upon use of a strut-segmented mask with struts providing mechanical support to permit thinned mask segments consequently yielding improved resolution. 'Stitching'--positioning of projected segment images to yield a satisfactory continuous image--is aided by lithographically defined skirts forming a continuous border within strut-supported segments.

Device manufacture involving step-and-scan delineation

Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on discrimination as between scattered and unscattered radiation by accelerated electrons. Use of such masks is of value as applied to scanning systems providing for dynamic correction of aberrations by physical movement of or field shaping of the objective lens to maintain the optical axis coincident with the scanning information-scanning beam.

Device manufacture involving lithographic processing

Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on discrimination as between scattered and unscattered radiation by accelerated electrons.

Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on descrimination as between scattered and unscattered radiation.

Growing community of inventors

Chatham, NJ, United States of America

Steven D Berger