Browse Prior Art Database

Method for Forming Wiring Patterns and Vias on a Variety of Substrates

IP.com Disclosure Number: IPCOM000036834D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 134K

Publishing Venue

IBM

Related People

Amendola, A: AUTHOR [+5]

Abstract

This article describes a new method of defining wiring patterns and vias with pure metals or metallic alloys on various ceramic greensheets, pressed and fired ceramic substrates, or polymer surfaces. The disclosed procedure has a capability for obtaining higher resolution wiring patterns by lithography of finer dimensions than that obtainable through the use of conventional screening techniques.

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Method for Forming Wiring Patterns and Vias on a Variety of Substrates

This article describes a new method of defining wiring patterns and vias with pure metals or metallic alloys on various ceramic greensheets, pressed and fired ceramic substrates, or polymer surfaces. The disclosed procedure has a capability for obtaining higher resolution wiring patterns by lithography of finer dimensions than that obtainable through the use of conventional screening techniques.

The process described employs a class of organo-metallic compounds known as chelates. These are available in a wide range of controlled compositions and are easily synthesized. Solids at room temperature, they are readily decomposed at relatively low (approximately 500oC) temperatures to form metal and volatile decomposition products. The chelate formed between copper and acetylacetone, for example, is typical of this class of compounds and can be isolated as a solid. A variety of such metal-organics having approximately similar physical properties can be made including cobalt, chromium, iron, magnesium, aluminum and others.

A thin, uniform layer of an organo-metallic, e.g., copper chelate, is deposited as a powder on the surface of the substrate material. The desired wiring pattern is then "developed" in the powder layer by selective application of heat, e.g., by laser. The organo- metallic will decompose only where heat is applied, forming an adherent pattern of the metal contained in the compound. The organic portion of the chelate will form decomposition products which will volatize away. The underdeveloped organo-metallic can then be physically removed from the substrate surface by dissolving the unreacted organo- metallic in an appropriate solvent or by other means.

Most compounds of this class have high melting points, ranging to above 200oC, and are stable enough to sublime in vacuum. This property lends itself to the formation of thin uniform coatings of the organo-metallic on a variety of surfaces. The employment of very thin coatings of chelates which are achieved by casting from solution is also a practical approach.

The wiring pattern is written with the use of a scanning laser, in much the same fashion as an E-beam system is employed in microelectronic device fabrication. In addition to laser influenced decomposition, an E-beam or a high intensity heat lamp can be employed in conjunction with a suitable full-field mask to control unwanted thermal decomposition in areas where no metal is desired. In forming the wiring pattern, the highest resolution ca...