A novel laser direct write technique for fabrication of thin film MICs

Abstract

Fig. 5. Loadingiunloading scheme diagramWhen the loader-unloader moves close enough to the carrier. the coils are energized and the electromagnetic fields generated by the coils attract the permanent magnets and pull the clips apart to permit the wafer to fit between the clips. Next, the loader-unloader lowers the wafer onto the carrier. Then the vacuum pump and coils are tumed off. The solenoid currents are tumed off gradually to let the clips gently begin to hold the wafer on the carrier. T o complete the loading process. the loader-unloader moves downward slightly and then moves out from under the carrier.The control steps for unloading the wafer are the reverse of those for loading the wafer and can be summarized as follows: First, the loader-unloader approaches the camer with both the solenoids and the vacuum pump tumed off. The loader-unloader positions itself under the wafer carrier. Next the coils are energized so as to pull apart the clips and release the wafer. Then the loader-unloader moves up until it almost touches the bottom surface of the wafer and the vacuum pump switches on to hold the wafer against the camer while the loader-unloader moves up further. The loaderunloader lifts the wafer off of the camer and the coils turn off after the wafer is raised out of the range of the clips. Finally the loaderunloader moves the wafer to a new target position. IV. EXPERIMENTAL RESULTS A N D CONCLUDING REMARKSThe feasibility test was a success in many ways. The wafer was firmly held in place on the loader-unloader during transport and securely held onto the camer by the clips. When the solenoids were switched on, the clips released the wafer satisfactorily and the wafer was removed from the carrier very smoothly. During the loading process, before the wafer was moved into the working range of the clips, the magnetic fields generated by the coils pulled the magnets apart and successfully opened the clips. After the wafer was loaded onto the carrier, the vacuum pump and coils were tumed off, and the wafer was delicately held on the carrier. Each of the loading and unloading processes took less than a few seconds.The loading-unloading operations were very smooth and the wafer was delicately handled during the operations. While the experiment was camed out with a stationary camer instead of a freely floating one, the validity of the experiment of the loading-unloading system is not affected by this fact. The feasibility test confirmed that successful implementation of the design with a maglev transport path can be expected.We conclude that the loading-unloading scheme proposed and the camer designed were proven to be quite feasible. The magnetic clamping principle upon which the camer and loader-unloader were designed is clearly a good choice. Magnetic clamping helps eliminate the requirement for a power supply to the carrier and therefore releases the carrier from a need for any mechanical tether. It is thus well suited for free floating levitation along a transport path. The weight of the camer was increased v...

Laser Enhanced Electroless Plating of Micron-Scale Copper Wires

“…1,2 LDW is potentially attractive in semiconductor device customization, repair, prototyping, and packaging applications. [3][4][5] Copper is an important metallization material in microelectronic circuits 6,7 and multichip module interconnections, 8,9 largely because of its low electrical resistivity. A major limitation of LDW technologies for device metallization applications using laser chemical vapor deposition (LCVD) techniques has been the lack of Cu precursors with sufficiently high vapor pressure.…”