Here is the abstract you requested from the IMAPS_2016 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Performance Evaluation of Gold (Au) Wire and Ribbon Interconnects in High Frequency RF Circuits|
|Keywords: wire bonding, Au ribbon bonding, RF circuit interconnects|
|Gold (Au) wires and ribbons are widely being used in military and space applications of high frequency RF/microwave circuits. The purpose of this study is to examine the RF performance of different dimensions of Au wires & ribbons which are typically bonded in cascade and parallel forms in the circuits operating microwave frequencies within 1-50 GHz. The second goal of this study is to establish a performance chart/handbook of Au wires, ribbons for high frequency circuit designers in order to show them which type of wire or ribbon as well as which type of interconnect form is suitable for their intended design. First, the test circuit board is manufactured by using thin film technology in order to prevent any errors may come from chip & wire, epoxy attach method. The substrate material of circuit board is chosen as Alumina to minimize losses and the material of wires, ribbons are chosen as %99.99 pure Gold. Au plated copper traces are used as conductive layers for optimal reliability and conductivity in the test circuit board. Automated thermo-sonic ball bonders are used for Au round wire bonds to reduce process errors. Manual parallel gap resistance welding is used for Au ribbons and always pay great attention to form the same length by using high magnification microscopes. The experiment conducted with the help of 0.7 mil, 1 mil round wires and 3x0.5 mil, 3x1 mil, 7x1 mil and 10x1 mil ribbons. Single bonds, parallel double bonds as well as double V-type bonds are performed on the circuit pads. The RF tests (S11-S22 return losses and S21 insertion loss) we performed showed that 0.7 mil and 1 mil round wires can be used in the frequency range of 0-20 GHz circuits. A better RF test result can be achieved if double parallel bonding method is used. Even better results can be gained V-type double bonding method. For higher frequency range, 20 to 50 GHz, 3x0.5 mil, 3x1 mil, 7x1 mil and 10x1 mil ribbons should be used. On the other hand, the bare chip bonding pads and dimensions of transmission line conductive layer bond pads are limiting the usage of desired ribbon. Also, in every bond group the maximum current load is experimented and determined in order to understand the selection of the right wire and/or ribbon dimension in DC circuits. Last but not least, a performance chart of RF wire/ribbon interconnects including a suggestion of bonding method with sustainable current load and shape is generated for design and application engineers who are dealing with high performance circuit efficiency.|
|Cenk ATALAN, Chief Production Engineer