Laser-induced diode linking for wafer-scale integration

Diodes formed by ion implantation and diffusion in a conventional CMOS process are positioned such that when desired they may be used to obtain an electrical link between two otherwise separate sections of the integrated circuit. Electrical connections so obtained enable the realization of wafer-scale ICs as demonstrated in recent applications. They theory of laser-beam application to silicon is discussed and it is shown how the various beam and substrate parameters effect the properties of the diode links. Particular attention is paid to the important issue of the reflectivity from the composite system. Careful analytical examinations of the resulting molten zone properties have been performed to fully qualify the use of laser radiation in this technology. Both scanning electron microscopy and secondary-ion mass spectrometry were used to examine such parameters as the lateral and in-depth extension of the molten zone. In addition, electrical measurements were carried out. The results for the various observables compare well with the theoretical predictions.>