SynopsisThe subject of this paper is an infrared and liquid chromatographic characterization of epoxy molding compounds of importance in the microelectronic manufacturing industry. A complete infrared description of resin extracts from 4000 to 700 cm-l is given for three nondisclosed commercial extracts via comparisons with model epoxy cresol novolac and phenol formaldehyde novolac resins and by observing those spectral alterations affected during cure. In addition, both the molecular weight distributions and the methodology of obtaining such for the resin and hardener components of the extracts are described. These results are based upon reversed phase liquid chromatography and infrared spectroscopic measurements. The analysis described in this paper demonstrates significant differences among materials that, by chromatography alone, appear to have only subtle variations in both the resin and hardener molecular weight distributions. These differences include not only the quantity of resin or hardener of a particular oligomeric molecular weight, but also the apparent resin-to-hardener stoichiometry of the combined system.
SYNOPSISThe evolution of organic vapors from encapsulants at elevated temperatures has been implicated as the source of the degradation of the gold-aluminum intermetallic of the wire that connects the bond pad to the leadframe in an integrated circuit. Gas chromatography/ infrared spectroscopy/mass spectrometry were used to study the decomposition of three commercial epoxy-novolac thermosetting compounds. Outgassing products have been identified and their origins discussed. Insight into the types of initiators used in encapsulants and their possible influence upon ball bond failure rates has been gained.
We have investigated the evolution of the microstructure, growth modes, and growth kinetics of β-SiC in a rapid thermal processor using FTIR, ESCA, and TEM. SiC layers were formed by reacting C2H4 with Si substrates between 900 and 1300°C at 5 torr. We found that SiC forms discrete nuclei at 900°C, a mixture of discrete nuclei with a thin β-SiC layer in between those nuclei at around 1000°C, and a continuous β-SiC layer above 1100°C. In all cases, β-SiC grows epitaxially on Si substrates. In addition, we identified that a graphitic carbon layer is formed on top of a continuous β-SiC layer. The thickness of the SiC layer was deduced from the integrated absorption spectra of FTIR and measured from the high resolution cross-sectional TEM micrographs. Kinetic data indicate that SiC grows rapidly at the initial stages of reaction. The growth rate, however, is retarded significantly as the reaction proceeds.
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