Browse Prior Art Database

CO-FIREABLE VIA METALLIZATION

IP.com Disclosure Number: IPCOM000006889D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2002-Feb-08
Document File: 1 page(s) / 84K

Publishing Venue

Motorola

Related People

James H. Lombard: AUTHOR [+4]

Abstract

The purpose of this study is to develop a co-freable platinum via metallization that is compatible with a neo- dymium titanate ceramic substrate material, and proba- bly other titanate ceramics. The use of this metallization is in the fabrication of multilayer ceramic packages, spe- c&ally as an interconnecting electrical path between ditferent circuit layers.

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INC. Technical Developments Volume 19 June 1993

CO-FIREABLE VIA METALLIZATION

by James H. Lombard, Rong Fong Huang, Carlos Sanchez and Russell Fryman

SUMMARY:

  The purpose of this study is to develop a co-freable platinum via metallization that is compatible with a neo- dymium titanate ceramic substrate material, and proba- bly other titanate ceramics. The use of this metallization is in the fabrication of multilayer ceramic packages, spe- c&ally as an interconnecting electrical path between ditferent circuit layers.

DISCUSSION:

  Co-tiring is the process of sintering a ceramic green sheet with a compatible metallization at the same time. The advantage of a co-firing process is that it can pro- vide a three dimensional electrical interconnect within the substrate. In this study, a new via paste was developed that can be used to co-tired with the neodymium tita- nate ceramics.

  The current conditions for c&ring neodymium tita- nate require 1300°C in an air atmosphere. At this tem- perature, most metals will oxidize or melt and thus are unsuitable for consideration. Only precious metals such as palladium (Pd) or platinum (Pt), which have high melting points and will not oxidize, can be used. How- ever, Pd cannot be used because it will form a weak intermetallic with bismuth, which is a constituent of the neodymium titanate ceramic tape. From the preceding conditions, this means that a possible choice for the via paste is a platinum mixture that has a compatible shrink- age with the ceramic tape. Furthermore, platinum is very stable and resistant to oxidation, so there are no subse- quent volume changes caused by oxidation of the con-

ductive particles. The via filling paste is a suspension of the conductive particles with ceramic particles in an organic vehicle. The control of quantities of the metal, ceramic and organic vehicle amounts and type are essen- tial to obtain the desired pro...