Electric measuring equipment output to reach ¥700 billion : JEE (Japan) 54 (February 1990)

Abstract

The increasing I/O-density of today’s packages is dealt with by using multilayer modules. Since there is also a trend towards faster interconnections by using optics, the extension of the interconnection module with V-grooves is in high demand. This paper reports on the electro-optical extensions of an earlier developed standard MCM-Si technology (Lernout et al., Journal of IMAPS (Europe) 1998; 15(1): 39–42; Ref. 1). The technology aspects of this standard MCM-Si technology are presented.The extended thin-film multilayer module is built up using two metal and three insulator layers. Additionally an implementation with low TCR resistors (NiCr) can be made. Fiber holding structures, namely V-grooves, are created into the bulk (100) silicon substrate by means of an anisotropic etching, performed in aqueous KOH. A passivation layer of silicon nitride, optimised towards low silicon content, served as protection mask during the KOH etching. The compatibility of this aggressive wet etching step with other processing steps is discussed. As for the insulators in the multilayer module, these high quality PECVD (Plasma Enhanced Chemical Vapour Deposition) layers are optimised towards low stress content and uniformity.Subsequently, the use of this interconnection substrate as a motherboard in multichip modules (MCM) is considered. The extension of the motherboard with V-grooves makes it possible to integrate opto-electronic (O/E) components, fibers and electronics on the same MCM-Si. Some of the major advantages are: low cost solution (saving non-used silicon area), compact assembly (carriers of fibers integrated with electronics), ability to reach higher frequencies (shorter interconnection distances),… Also low coupling losses between laser and fiber are achieved: the accuracy of V-grooves in silicon permits to place the fiber with high precision, and the self-aligning property of solder assures the control over the flip-chip (FC) mounted O/E-components (e.g. laser diodes).