Thermodynamic Analysis of Physical Vapor Deposition (PVD) Inorganic Thin Films on Low Temperature Cofired Ceramic (LTCC)
Abstract Low temperature cofired ceramic (LTCC) has been established as an excellent packaging technology for high reliability, high density microelectronics. The functionality and robustness of rework has been increased through the incorporation of a Physical Vapor Deposition (PVD) thin film Ti/Cu/Pt/Au metallization. PVD metallization is suitable for RF (Radio Frequency) applications as well as digital systems. Adhesion of the Ti “adhesion layer” to the LTCC as-fired surface is not well understood. While past work has established extrinsic parameters for delamination mechanisms of thin films on LTCC substrates, there is incomplete information regarding the intrinsic (i.e. thermodynamic) parameters in literature. This paper analyzes the thermodynamic favorability of adhesion between Ti, Cr, and their oxides coatings on LTCC (assumed as amorphous silica glass and Al2O3). Computational molecular calculations are used to determine interface energy as an indication of molecular stability over a range of temperatures. The end result will expand the understanding of thin film adhesion to LTCC surfaces and assist in increasing the long-term reliability of the interface bonding on RF microelectronic layers.