International Business Machines Corporation

Mukesh K Desai

Keith S Pennington

Ali Afzali-Ardakani

Eva Erika Simonyi

Ali Afzali-ardakani

Walter Crooks

Jan-Pieter Hoekstra

Bradford J Factor

Jean-Piet Hoekstra

Ronald T Cannavaro

Jahn P Hoekstra

Mun Sok Pak

A method for removing conductive metals on a semiconductor chip while leaving a foundation on which the conductive metal is in contact with substantially intact. The foundation includes a dielectric layer and a connecting stud. The dielectric layer is formed from a material which has a relatively high reactivity to an attack by a base, but has a relatively low reactivity to an attack by acid. A first planarization process is applied to the semiconductor chip, the first planarization process attacks the conductive metal at a high rate and is discontinued prior to when the connecting stud via is exposed to direct effects of the first planarization process. A second planarization process is applied to the semiconductor chip. The second planarization process attacks the conductive metal at a relatively high rate, but attacks the connecting stud at a low rate. The second planarization process substantially removes what is left of the conductive metal after the first planarization process. A sacrificial material is deposited over the semiconductor chip, the sacrificial material has an etch rate equal to, or higher than, the etch rate of the inter-level dielectric base.

Semiconductor chip reclamation technique involving multiple

Improved electroerosion recording media can be prepared by utilizing, on top of a polyester, paper, or metal substrate, a polyvinylbutyral polymer cross-linked with a mixed phenol-tert-butylphenol formaldehyde cross-linking agent as a base layer, and an erodible metallic layer sufficiently thin to be erodible in response to current pulses delivered by a stylus of an electroerosion printer. In a preferred embodiment, the polymeric layer further contains silica. The recording medium may also be top coated with a lubricating agent. The formulation provides excellent adhesion of the conductive layer, and allows the thickness of the aluminum to be increased up to 75%, resulting in an optical density (with aluminum as the metallic layer) of up to 3.5.

Electroerosion printing plates

An improved apparatus and process are described in which a direct negative is formed using commercially available multi-stylus recording heads. A negative precursor comprised of a transparent support and an opaque thermoplastic ink layer carried thereon, is brought into contact with an ink receiving medium comprised of a resistive layer and a thin conductive ink receiving layer thereon. Electrical currents are provided by the recording styli of the multi-stylus recording head to the resistive layer to provide sufficient heat to soften regions of the opaque ink brought into contact with the conductive layer, by which regions of said opaque ink are transferred to the ink receiving conductive layer. In this manner, a pattern of opaque ink regions is removed from the surface of said transparent support, whereby a direct negative is formed having light opaque and light transparent regions.

Direct negative from resistive ribbon

An improved thermal transfer resistive ribbon usable in high resolution printing comprising a dual resistive layer formed of a first layer of low resistivity and a second layer of high resistivity, method of production thereof, use thereof and apparatus including the same.

Resistive ribbon for high resolution printing

An improved apparatus and process are described in which metal images are transferred to a softenable receiving layer using commercially available multi-stylus recording heads. The transfer medium is comprised of a resistive layer and a thin metal layer thereon. Electrical currents are provided by the recording styli of the multi-stylus recording head. Localized electrical currents in the resistive layer provide sufficient heat in the metal layer to soften regions of a metable receiving layer when it is brought into contact with said heated metal layer. Metal imaging for use in printed circuit board manufacture and in formation of printing masters can be transferred by this technique.

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Fishkill, NY, United States of America

Mukesh K Desai