International Business Machines Corporation

Other

Janos Havas

John Anthony Fitzsimmons

John S Lechaton

Joseph S Logan

Edward J Leonard

Margaret Jane Lawson

Bryan N Rhoads

Gabor Paal

Prabodh R Shah

Paul N Chaloux, Jr

Alicia Dean

Jack R Franco

Barry C McCormick

Lewis J Rompala

Skinner Logan

A method of forming patterned films on a semiconductor substrate 10 includes the steps of depositing a hardened photo resist underlay 30 onto the substrate, then depositing a polyether sulfone release layer 32, then depositing a photo sensitive resist layer 34 and exposing an etching a metallization pattern 36, 38 to the substrate 10. The structure is then blanket deposited with a conductive layer 40 to thereby create a conductive contact stud 42. The film layer 40 and resist layer 34 are removed by dissolving the polyether sulfone layer 32 in an NMP solution and the photo resist underlayer 30 is then removed using a selective photo resist stripper composition.

Method for forming patterned films on a substrate

Photo resist stripper compositions comprising N-alkyl-2-pyrrolidone, 1,2-propanediol and tetraalkylammonium hydroxide. The photoresist strippers are useful at high stripping temperatures (105.degree. C.-125.degree. C.) to remove hard baked photoresist without damaging semiconductor substrates or metallurgy.

Photoresist stripper

Three-dimensional polymerization of resin glass on an underlay surface may cause uneven distribution of the layer and therefore uneven etching of the glass layer in subsequent processing. The glass remaining after an etching step can cause difficulties in further processing of the structure, such as causing metal opens in a metallization step. In order to control the three-dimensional polymerization; the underlay surface is treated with a short plasma treatment. The plasma oxidizing step renders the surface acidic, forcing the glass polymerization to occur in a two-dimensional mode thereby eliminating the threat of uneven distribution and its repercussions.

Underlay surface modification to control resin glass polymerization

A method for depositing thin film patterns of very small and controllable dimensions in the fabrication of integrated circuits which avoids edge tearing of the films. A non-photosensitive organic polymeric first masking layer is deposited on the integrated circuit substrate. Upon this layer is deposited a layer of silicon nitride using plasma deposition techniques employing a gaseous source. The silicon nitride layer is covered by a second masking layer, preferably an organic polymeric resist material, through which apertures are formed in preselected patterns using standard lithographic masking and etching techniques. The silicon nitride layer is then reactive ion etched with CF.sub.4 through the apertures formed in the second masking layer. The first masking layer is then etched through the apertures in the second masking layer and silicon nitride layer using reactive ion etching techniques. The etching of the first masking layer continues until the first masking layer is undercut beyond the edges of the aperture in the silicon nitride layer so that the silicon nitride layer forms an overhang of the aperture in the first masking layer. The thin film to be deposited is then applied over the resulting structure including the surface of the silicon nitride layer and the substrate exposed through the apertures. Because of the overhang, a discontinuity is formed between the thin film deposited upon the exposed surface of the substrate and that formed upon the outer surface of the silicon nitride layer so that when the first masking layer is dissolved, the film deposited upon the substrate is left without any edge tearing between it and the removed portions of the film.

Method of depositing thin films of small dimensions utilizing silicon

A method for forming coplanar thin films, particularly conductor-insulator patterns, on a substrate. A pattern which includes a first thin film and an expendable material deposited thereon is formed on the substrate. The expendable material is selected so that it can be selectively removed by an etchant which does not attack the first thin film or an insulator which is to be deposited. The second thin film is deposited by RF sputtering at a bias which is sufficiently high to cause substantial reemission of the second film. This results in the covering of the exposed substrate surfaces and the upper surface of the material with the second film but leaving the side surfaces of the material exposed. The expendable material is then chemically etched so as to lift-off both the material and the second film deposited thereon, thereby leaving a coplanar pattern of first and second thin films. In the preferred embodiment, the first thin film is a conductor and the RF sputtered second thin film is an insulator such as glass. Alternatively, the first thin film could be the insulator with the RF sputtered second film being the conductor, or both thin films could be dissimilar metals or insulators.

Structure for making coplanar layers of thin films

A method for forming coplanar thin films, particularly conductor-insulator patterns, on a substrate. A pattern which includes a first thin film and an expendable material deposited thereon is formed on the substrate. The expendable material is selected so that it can be selectively removed by an etchant which does not attack the first thin film or an insulator which is to be deposited. The second thin film is deposited by RF sputtering at a bias which is sufficiently high to cause substantial reemission of the second film. This results in the covering of the exposed substrate surfaces and the upper surface of the material with the second film but leaving the side surfaces of the material exposed. The expendable material is then chemically etched so as to lift-off both the material and the second film deposited thereon, thereby leaving a coplanar pattern of first and second thin films. In the preferred embodiment, the first thin film is a conductor and the RF sputtered second thin film is an insulator such as glass. Alternatively, the first thin film could be the insulator with the RF sputtered second film being the conductor, or both thin films could be dissimilar metals or insulators. Via hole studs, or feedthroughs, which are metallic interconnections between a first level conductive pattern (metallization) and a second level conductive pattern, may be formed by repeating substantially the same steps atop the first conductive pattern at desired locations. As many substantially coplanar levels as desired may be formed without the need for etching the second thin film.

Making coplanar layers of thin films

A lift-off method for use in depositing thin films in the fabrication of integrated circuits which avoids edge tearing of the films. The method involves depositing an organic polymeric first masking material on a substrate, and forming on said material a layer of a polydimethylsiloxane resin material. The material, in turn, is covered by a second masking layer, preferably an organic polymeric resist material into which openings are placed in a selected pattern utilizing lithographic techniques. Then, conforming openings are placed in the underlying polydimethylsiloxane resin material and the openings are extended through the underlying resist material by successive reactive sputter etching steps to expose the substrate surface in the aforesaid selected pattern. The thin film to be deposited is then applied over the resulting structure; it is, thereby, deposited on the substrate in said openings. The final reactive sputter etching step affords edges in the openings through the resin material layer which overhang the edges in the openings through the first masking layer affording easy lift-off of the unwanted areas of the deposited film when the first masking layer is totally removed by application of solvent.

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Hopewell Junction, NY, United States of America

Janos Havas