Ananda Hosakere Kumar

Dual-Level Metal (DLM) method for fabricating thin film wiring structures

This paper describes a fabrication method for multilevel, thin film wiring in which each wiring level and a solid via or stud to the level below, are formed as one integral unit. The processing scheme described makes use of a photosensitive polyimide (PSPI) for defining the wiring channels and a non-photosensitive polyimide for the vias. The via opening in the non-photosensitive polyimide is formed by laser ablation while the wiring channels are formed in the PSPI layer by photolithography. The via hole and the channels in the PSPI are filled in the same metallization step consisting of electroplating copper over a sputtered seed layer. The wiring pattern is finally delineated when a planarization step removes the excess plated copper. This processing method, which we refer to as the Dual Layer Metallization (DLM) method, is found to be very economical, in terms of the number of process steps involved, for forming multilevel, polyimide-copper wiring structures.<<ETX>>

Package Sealing and Encapsulation

The packaging is defined as interconnecting, powering, cooling, and protecting integrated circuits. This chapter addresses the protection of semiconductor devices by means of sealing and encapsulation processes after the device packaging is completed. In addition to providing protection of devices, sealing and encapsulation must also protect the package and its package wiring so as to provide the required reliability of the packaged devices. Figure 14-1 illustrates the basic concepts of sealing and encapsulation.

Palladium-catalyzed sintering of molybdenum paste applied to multilayer substrate fabrication

This paper describes a novel method for densifying the surfaces of external, thick film molybdenum circuit features of multilayer ceramic substrates using palladium as a sintering catalyst. Such dense sintering of the surface effectively prevents the formation of undesirable pools of glass on the surfaces of the external features, making it possible to perform contact-probe electrical testing prior to plating and to nickel plate the molybdenum features without the customary cleaning steps needed to clear the pools of glass.<<ETX>>