Clad Metal Circuit Board Substrates for Direct Mounting of Ceramic Chip Carriers

Abstract

If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation.ABSTRACT-For a full realisation of the packaging advantages of leadless ceramic chip carriers, these devices will be surface mounted on large area printed circuit boards. However, thermal management and solder joint reliability concerns preclude the usage of conventional board materials and manufacturing processes in most high reliability applications.A new approach for achieving rugged, large area PCBs, incorporating thermal planes and the necessary thermal expansion match to chip carriers is described in this paper. The approach is based upon the use of a clad metal core substrate material fabricated from high conductivity copper and low thermal expansion rate Invar TM, a 36% nickel-64% iron alloy. Mechanical, electrical and thermal properties of this clad metal are presented as well as techniques for adaption of PCB and porcelain/thick film technologies.Finally, other potential applications for this clad metal in the electronics industry are discussed.

Sodium Borohydride Reduction of Aqueous Silver-Iron-Nickel Solutions: a Chemical Route to Synthesis of Low Thermal Expansion–High Conductivity Ag-Invar Alloys

“…The thermal expansion vs temperature data were used to calculate the average CTE, a, over the temperature range of 20°C to 100°C using Eq. [1]:…”

“…Both of these approaches effectively reduce heat or thermal strain, and thereby increase the reliability of modern microelectronic or optoelectronic systems. Successful implementations of low CTE, high conductivity core constraining layers include clad metals such as copper-Invar-copper, [1][2][3] carbon fiber-based cores, [4,5] and carbon-SiC laminate composites. [6] A number of composite packaging materials have been explored for use as thermal management substrates in thermally demanding components such as power amplifiers, laser diodes, thermoelectric coolers, and radio frequency (RF) and microwave devices.…”