Spatially coupled bipolar

The Construction of Circuitry Using Spatially Coupled Bipolar Electrochemistry... 

The formation of electrical contacts between metal structures and devices is an integral aspect of circuit construction at all scales of commercial importance. Currently photolithographic, screen printing and microsoldering techniques are the methods of choice to establish connections. However, these approaches require masks, templates or intimate physical contact with the components. Spatially Coupled Bipolar Electrochemistry (SCBE) is a novel technique which makes use of electric fields to create electrical connections between components, which not only avoids physical contact but is also applicable in principle to the formation of three dimensional circuitry. The SCBE technique has been developed to a point where the construction of functional robust circuits has been achieved. Preliminary data demonstrating the application of this approach to the formation of polypyrrole bridges between isolated gold structures is also presented. 

We have demonstrated a novel method to create either fi eestanding or surface-boxmd wires capable of establishing electrical contacts between isolated metal structures. The technique relies on spatially coupled electrodissolution and electrodeposition mediated by an electric field. Such bipolar conditions avoid the need to physically contact the metallic components in the system, which should prove to be a considerable advantage when dealing with far smaller components. In the case of wire formation on circuit boards, the metallic paths laid down serve as templates for an electroless deposition step, which yields robust and adherent electrical connections. In principle, the method is not limited to planar geometries. The application of electric field vectors in selected directions through an array of conductive structures in a porous medium may represent a powerfijl approach to the formation of three-dimensional circuitry. Furthermore the use of a conductive polymer allows the use of metal structures which do not electrodissolve in the medium. 

Ion implantation has become the dominant doping technique, particularly in the fabrication of bipolar-CMOS devices and in the formation of shallow junctions. Laser ablation sampling coupled with ICP-MS was applied recently to the determination of total dopant dose. Since this technique spatially and temporally separates the sampling and ionization steps, it has the potential to produce more quantitative results than SIMS for trace elements in a given matrix. Wafer surface analysis can also be used to monitor the contamination induced hy different process steps. The importance, in terms of contamination contrihution, of the chamber components used for film deposition and ion implantation was demonstrated, as was the effect of cleaning bath solution purity. ... 

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