Advanced Photo-imageable Dielectric Film Enabling Low CTE and sub-5-Micrometer Patterning for Next Generation Build-up Layer

Next generation build up layer patterning materials required to meet ultra-fine via patterning (smaller than 5 micrometer) and good thermomechanical properties such as low coefficient of thermal expansion (CTE) simultaneously. We have developed a novel film type photo-imageable dielectrics (PID) that meets these requirements at the same time. This novel PID film developed by following two step process. First, liquid-type dielectric material enabling ultra-high resolution was developed. Second, surface-treated nano-sized silica filler was mixed and dry film was manufactured. The new liquid type PID film developed achieved high resolution with an aspect ratio of 1:5 and was shown to be applicable to a wide range of film thicknesses. Furthermore, it was confirmed that PID has well-balanced thermomechanical properties such as CTE of 50 ppm/°C or tensile strength of 113 MPa with good reliability, even though it can be cured at a low temperature of 200°C. The PID film, which incorporates nanofiller into liquid type PID, has good mechanical properties with a CTE of 31 ppm/°C while exhibiting resolution characteristics with an aspect ratio of 1:1.75. These results indicate that the newly developed PID is suitable for applications in next-generation build-up layers.