抄録
We have developed a novel fine-pitch multilayer wiring technology for wafer level packages using mechanical grinding. In this process, a dielectric film containing a rubber filler was first laminated and then cured over electroplated Cu posts. Second, the dielectric layer was subjected to mechanical grinding in order to expose the Cu posts. Finally, a Cu layer was deposited on the dielectric layer using electroless plating. Here, in order to improve the adhesion between the dielectric layer and the Cu layer, the dielectric layer was exposed to oxygen plasma and then chemically treated with a coupling agent. From this study, we found that the rubber filler enhances the adhesion strength between the dielectric layer and Cu wirings. Also, we successfully fabricated fine-pitch wirings with line/space of 5 μm/5 μm with the new process using the new dielectric film.
