Radio frequency characterization of bonding wire interconnections in a molded chip

Radio frequency characteristics at frequencies ranging from 0.1 GHz to 10 GHz of bonding wire interconnections in a low-cost lightweight 64 pin 9 mm×9 mm molded chip were investigated. The work in this paper was performed to realize the length effect, parasitic effect, impedance matching, and crosstalk phenomena of bonding wires in a molded chip. Bonding wires of length between 2 mm (the shortest) and 2.5 mm (the longest) in our molded chips were selected as test samples. Agreement between measurements and simulations from HFSS was observed, across 10 GHz of bandwidth, to be within 1 dB for return loss and 0.2 dB for insertion loss, respectively. Experimental results of 2 mm and 2.5 mm long bonding wires show that resistive and inductive effects of the wires themselves (i.e. length effect) have little impact on S-parameters in these test chips. In addition, the RF performance with a proposed matching capacitor to the G-S-G single-ended bonding wire and crosstalk phenomena between two adjacent signal wires was also evaluated. This research also shows definitely that parasitic effects result from the molding and pads in these test chips play certainly important roles on insertion loss and return loss.