Characterisation of Cr intermediate layers in Cu-C-system with SIMS method

In the design of new high speed chip generations, the greatest problem is t o bleed off process heat during their operation. The installation of heat s inks onto such chips is necessary. A copper-carbon (Cu-C) composite is one possible material. It combines high thermal conductivity with low density a nd tailorable coefficient of thermal expansion (CTE). Because of low wettab ility of carbon by copper, a thin layer of chromium (Cr) has to be deposite d first to contact copper with the carbon fibers. The optimization of processing parameters was done on vitreous carbon subst rates (Sigradur G) as a model for carbon fibers. Onto these substrates, 2 n m chromium and I tm copper were deposited. In the later serial fabrication of the composite, a hot pressing step will follow the deposition, which is simulated with a heat treatment of the compound. Secondary ion mass spectro metry (SIMS) investigations were done to obtain information on the depth di stribution of the main elements copper, chromium and carbon. Two samples, o ne as deposited and one subjected to a heat treatment after deposition are compared in this investigation. (C) 2001 Published by Elsevier Science B.V.