Novel Photosensitive Dielectric Material with Superior Electric Insulation and Warpage Suppression for Organic Interposers in Reliable 2.1D Package

Abstract

2.1D package is expected to lead the progresses of technology drivers such as 5G communications and AI (Artificial Intelligence), however, the organic interposers for 2.1D still have technological challenges in fine patterning. In this work, the novel photosensitive dielectric material aiming for 2.1D organic interposers was developed and essential features were studied. In designing the photosensitive material, the new photo-polymerizable compound with high flexibility and superior insulation reliability was prepared as a main component. The obtained photosensitive dielectric material had film form which contributes to the reduction of process cost as compared with liquid type materials. The developed photosensitive material showed excellent insulation reliability in HAST (High Accelerated Stress Test) with 5 μm/5 μm and 2 μm/2 μm line and space test vehicles. The evaluation of via hole patterning confirmed that 5 μm via holes were formed on the developed material without any technical issue. In addition, the warpages of 2.1D model structures with the photosensitive dielectric material were studied to investigate the warpage suppression effect derived from the flexible photo-polymerizable compound. The test vehicles with the photosensitive material showed smaller warpage than those with typical epoxy composition, moreover the suppression effect became stronger as the package size increased. Thus the effectiveness of the newly developed photosensitive dielectric material was successfully demonstrated.