Amoco Corporation

Sri International

Stanford Research Institute

Xmr, Inc.

Thomas J Magee

Malcolm Thackray

Charles S Leung

Richard R Pettijohn

Matt Lehmann

John F Osborne

Charles H Leung

Richard L Press

Shelley A Stewart

Peter Gildea

The invention relates to a new method for cleaning chemical, metallic and particulate contaminants from solid surfaces. The new method comprises irradiating the surface with essentially ultraviolet laser radiation whose parameters are selected to avoid causing substantial chemical or physical change at the surface.

Method for cleaning surfaces using UV lasers

Nonrefractory micrometer-thick deposited metal or metallization, for example, aluminum and aluminum alloy films, on integrated circuits are planarized by momentarily melting them with optical pulses from a laser, such as a xenon chloride excimer laser. The substrate, as well as any intervening dielectric and conducive layers, are preheated to preferably one-half the melting temperature of the metal to be planarized, thereby enhancing reflow of the metal upon melting. This improves planarization and reduces stress in the resolidified metal. Laser planarization offers an attractive technique for fabricating multilayer interconnect structures, particularly where a number of ground or power planes are included. Excellent step coverage and via filling is achieved without damaging lower layers of interconnect.

Laser planarization of nonrefractory metal during integrated circuit

A method of forming a microscopically texturized surface on a crystalline semiconductor material is disclosed which method includes the use of a radioactive source for uniformly irradiating the surface. The radioactive source includes a plane surface having a uniform distribution of radioactive material thereon In one arrangement the radioactive source surface area is at least the size of the polished crystalline semiconductor surface to be texturized, and the radioactive source is positioned closely adjacent the polished surface for a predetermined time period for uniform irradiation of the same. If desired, the radioactive source and crystalline surface may be relatively movable during irradiation of the surface, in which case the source may be in the form of an elongated strip of sufficient length to extend beyond opposite edges of the polished surface area to be texturized. In any case, the large-surface area radioactive source produces substantially uniform distribution of damage tracks in the crystalline surface, which surface then is anisotropically etched by use of a suitable etching solution. The damage tracks provide etching sites along which etching proceeds at a greater rate than in the undamaged area. Generally the surface to be texturized comprises the (100) orientation surface of a crystalline semiconductor material, such as silicon, at which surface etching preferentially proceeds for exposure of the (111) planes which intersect the surface with fourfold symmetry. With this method a controllable size distribution of tetrahedra may be formed over a large surface.

Method of controlled surface texturization of crystalline semiconductor

There is provided a method and means for establishing storage sites in photodichroic materials using ion implantation.

Memory system using ion implanted photodichroic materials

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Belmont, CA, United States of America

Thomas J Magee