PROCESS CHARACTERIZATION FOR THE ASSEMBLY OF 01005 COMPONENTS

摘要

In the quest to miniaturize electronic assemblies, a focus of the industry has been to reduce the size of passive components. Resistors and capacitors can now be produced in extremely miniaturized 01005 package sizes. The objective of this research was to study the capability of the current manufacturing equipments used to assemble these 01005 components. This research draws relevant information from the experience gathered while assembling 0201 sized components. Specifically, the effect of pad design, stencil aperture artwork, print parameters, solder paste type and composition, component placement, and reflow characteristics were studied. The volume of solder paste transferred, considering the small apertures and low area ratio, is a critical factor in fine pitch printing. The consistency of the paste deposited and the transfer efficiency should also be closely monitored. In this research, the design for the stencil accounted for the above factors before deciding on the stencil thickness and aperture dimensions. Tests were carried out with both leadrich and lead-free solder pastes. A suitable measurement technique for the inspection of solder paste volume through an Automatic Optical Inspection (AOI) system was employed. Design of Experiments (DOE) based tests were devised to evaluate the effect of the different factors on the volume of solder paste transferred. Theoretical knowledge was used to support the various assumptions made during the experiment. The goal was to identify a suitable process window based on different materials used, process parameters and external factors. Additionally, the study resulted in identifying critical printer parameters to obtain an acceptable transfer efficiency and repeatability for solder paste deposits for 01005 devices.