International Business Machines Corporation

Giorgio G Via

Edward C Fredericks

Gangadhara Swami Mathad

David Stanasolovich

Madan M Nanda

John F Conway

Herbert L Greenhaus

A process and structure for depositing metal lines in a lift-off process is disclosed. The process comprises the deposition of a four-layer structure or lift-off stencil, comprising a first layer of a lift-off polymer etchable in oxygen plasma, a first barrier layer of hexamethyldisilizane (HMDS) resistant to an oxygenplasma, a second lift-off layer and a second barrier layer. Once these layers are deposited, a layer of photoresist is deposited and lithographically defined with the metal conductor pattern desired. The layers are then sequentially etched with oxygen and CF.sub.4, resulting in a dual overhang lift-off structure. Metal is then deposited by evaporation or sputtering through the lift-off structure. Following metal deposition, the stencil is lifted-off in a solvent such as N-methylpyrroldone (NMP).

Process of forming a dual overhang collimated lift-off stencil with

An apparatus and method for characterizing lithography imaging to quickly optimize a lithography process is described. The apparatus consists of two lithography masks for use with an optical stepper, ion-beam or x-ray lithography tool. The first mask is used for creating topography on the wafer substrate, and is patterned with groups of large elements arranged in orthogonal and angular directions. The second mask is used for defining a periodic pattern over the large elements. Preferably, the periodic pattern is in the same order of dimension as the critical element on the integrated circuit. A method is provided for characterizing lithography tools which do not have lithography masks such as an electron beam exposure tool.

Lithography imaging tool and related photolithographic processes

A process and structure for depositing metal lines in a lift-off process is disclosed. The process comprises the deposition of a four-layer structure or lift-off stencil, comprising a first layer of a lift-off polymer etchable in oxygen plasma, a first barrier layer of hexamethyldisilizane (HMDS) resistant to an oxygen plasma, a second lift-off layer and a second barrier layer. Once these layers are deposited, a layer of photoresist is deposited and lithographically defined with the metal conductor pattern desired. The layers are then sequentially etched with oxygen and CF.sub.4, resulting in a dual overhang lift-off structure. Metal is then deposited by evaporation or sputtering through the lift-off structure. Following metal deposition, the stencil is lifted-off in a solvent such as N-methylpyrrolidone (NMP).

Collimated metal deposition

A method which provides for a permanent planarization layer on a multilayer integrated circuit. The planarization layer resides above other circuit layers which reflect incident light. A layer of photoresist is formed over the planarization layers and imaged through a mask with circuit defining structure. During exposure of the photoresist, incident light passes through the planarization layer. Scattering from the boundary of the planarization layer and photoresist is minimized because the index of refraction of the planarization layer is substantially equal to the index of refraction of the photoresist. Light reflected from the underlaying layers is substantially absorbed by the planarization layer. Reduction of the reflected and scattered light results in improved resolution of developed images in photoresist. The developed images, when further processed into interconnecting conductors have improved definition, avoiding the additional process steps of applying a temporary dye or other light impervious layer.

Method for improving resolution in microelectronic circuits using

A photoresist photolithographic process is disclosed which provides for a single development step to develop a dual layer photoresist for lift-off, reactive ion etching, or ion implantation processes requiring a precise aperture size at the top of the photoresist layer. The process involves the deposition of two compositionally similar layers, with the first layer having the characteristic of being soluble in a developer after exposure to light and baking, and the second layer having the characteristic of being insoluble in the same developer after having been exposed to light and baked. With these two distinct characteristics for the two layers of photoresist, the effective aperture for windows in the composite photoresist can be tightly controlled in its cross-sectional dimension in the face of large variations in the developer concentration and development time.

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McLean, VA, United States of America

Giorgio G Via