Ultra-small 0201 passive device process optimization and it's effective inspection

Ultra small passive device such as 0201 component was finding the way into designs that were previously dominated by 0805, 0603 and 0402 packages. The main driving force in this package was the evolution of cell phones, PDA and other miniature electronic products. In addition, some components used in MCM (multichip module) reduce overall package size needs 0201 technology. With much talk on the needs for ultra small 0201 passive device, work has been carried out to define the optimum land pad configuration for robust manufacturing process. The designing of the land pad configuration has considered the used of automatic optical inspection system for defects checking. In this present study, commercially available 0201 component suppliers were used for the experiment. Design of experiments matrix was used to test the selected optimal land pad configuration. All the 0201 components were conformed to RoHS requirement. The oven used was with nitrogen environment and convection heats reflow. The solder paste used was Pb-free(95.8Sn3.5Ag0.7Cu), no clean and from prominent paste supplier. The respond used was the assembly yield. Defects such as tombstone, misalignment, missing component and solder bridge were determined the yield in our experiment. Both the resistor and capacitor were used in this study. There was cross section check to ensure no solder bridging under the ultra small 0201 passive device. The experiment included the study of using automatic optical inspection system to check for the defects. This was imperative as the component was too small for effective visual inspection in mass manufacturing environment.