Laser-Induced Diode Linking for Wafer-Scale Integration
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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The use of laser beam melting of silicon for the purpose of forming electrical links between two adjacent diodes is studied. The diodes, which are 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 separated sections of the integrated circuit. Electrical connections so obtained enable the realization of wafer-scale ICs, as demonstrated in recent applications. The theory of laser-beam application to silicon is discussed, and the various beam and substrate parameters are shown to affect 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 in order 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.
- Manufacturing and Industrial Engineering and Control of Production Systems
- Solid State Physics