Browse Prior Art Database

LED Substrate Fabrication

IP.com Disclosure Number: IPCOM000047004D
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Ries, MD: AUTHOR [+3]

Abstract

Described is a technique for fabricating LED (light-emitting diode) arrays using single-level metallization to provide both anode and cathode connections. High density linear arrays are possible. To fabricate a high density LED array, a plurality of multidiode array chips are mounted on a substrate, the substrates then being assembled to produce long, linear arrays. This is illustrated in Fig. 1. The substrates must provide anode connections (top), cathode connections (bottom), thermal conduction, and thermal expansion matched with the LED array chips. The substrate is fabricated by metallizing an alumina ceramic part and defining conductive paths by photoetching. The density of lines and contacts required for a high density array usually precludes using single-layer metallization for both anode and cathode connections.

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LED Substrate Fabrication

Described is a technique for fabricating LED (light-emitting diode) arrays using single-level metallization to provide both anode and cathode connections. High density linear arrays are possible. To fabricate a high density LED array, a plurality of multidiode array chips are mounted on a substrate, the substrates then being assembled to produce long, linear arrays. This is illustrated in Fig. 1. The substrates must provide anode connections (top), cathode connections (bottom), thermal conduction, and thermal expansion matched with the LED array chips. The substrate is fabricated by metallizing an alumina ceramic part and defining conductive paths by photoetching. The density of lines and contacts required for a high density array usually precludes using single-layer metallization for both anode and cathode connections. To avoid the expense accompanying multilayer metallization, a substrate can be fabricated to provide anode connections on the top and a common cathode connection on the bottom surface, as shown in Fig. 2. The cathode metallization is carried from the top to the bottom surface of the substrate by metallization bands at the ends of the substrate. The fabrication is readily performed by the following steps. First, the machined (ceramic) part is metallized on five sides, i.e., the top and four sides, by conventional sputtering or vacuum metallization processes. Next, the metallization is coated with a conventional photoresist...