High-aspect-ratio Sub-2-μm Vias Using Thermal Imprint with Build-up Resin

摘要

We developed a fabrication method of high-aspect-ratio fine vias with a build-up resin. The build-up resin composed of a thermosetting resin and silica fillers has low coefficient of thermal expansion and low dielectric constant. Thermal imprint was performed to form the high-aspect-ratio fine via holes on the build-up resin. The imprint mold with high-aspect-ratio fine pillar patterns was fabricated by photolithography and deep reactive ion etching. The residual layer consisted of the thermosetting resin and the silica filler was removed by O₂/CHF₃ plasma etching. The via of 1.2 μm in diameter with aspect ratio of 5.5, and 5.0 μm in pitch was successfully fabricated followed by Au electroplating. The proposed fabrication method is applicable for high-density 3-dimensional and 2.5-dimensional integration technologies.