LASER-INDUCED MELTING OF THIN CONDUCTING FILMS .1. THE ADIABATIC APPROXIMATION

We study the application of pulsed laser radiation in the melting of thin conducting films. This is used to realize both deletive and additive redundancy techniques, common in defect avoidance and customization processes. An extrapolation of these techniques to build large integrated circuits forms the basis to the technology of wafer-scale integration. We discuss the theory of laser-beam application to aluminum films, and show how the various beam and substrate parameters affect the properties of the cuts and links so obtained. We pay particular attention to the geometrical constraints of the system and discuss in detail the effects owing to the various physical parameters. Closed-form analytic expressions have been obtained for the relevant quantities of the system. No adjustable parameters are involved in the calculation of the various thermal properties of the system. A careful analytical examination of the resulting molten zone properties has been performed in order to fully quantify the use of laser melting in wafer-scale applications. Scanning electron microscopy of the affected zones has been used to examine such parameters as the shape and lateral extension of the molten region. The experimental results compare well with the theoretical predictions.