Novel, high density R/C terminating networks

Integrated 100 pF/50 Ω R/C terminators with an 0402 footprint were designed, fabricated and evaluated on Si and glass substrates. These structures consisted of compound anodized Ta capacitors and a Ta metal resistor, and required only two mask steps, two metal layers, no vias, and patterning by wet etching. The component values can be adjusted without having to change the size of the terminators or make new masks because the capacitance may be modified by changing the anodization voltage and the resistance by changing the Ta thickness. Each terminator showed classic R/C behavior near expected values. Of the 600 terminators fabricated on two 5 inch wafers, only two were defective due to capacitor shorts and none due to resistor faults. Further size reductions are possible; these devices could be integrated as 8, 32 or 64-wide arrays for bus termination. The device density is limited only by a reasonable I/O pitch for CSP-like attachment