Hideki Higashitani

Next generation ALIVH substrate for bare chip direct mounting

The next generation ALIVH(R) substrate named ALIVH(R)-FB substrate was developed. The ALIVH-FB substrate has a structure that fine layers were formed on the surface of the conventional ALIVH substrate. The design rule of the core layer is Line/Space (LIS)=50/50 /spl mu/m, Via hole diameter/Land diameter (V/L)=120/250 /spl mu/m and the rule of fine layer is L/S=25/25 /spl mu/m, V/L=50/150 /spl mu/m. Three technologies are developed: thin insulator layer by the film material with high heat resistance; fine via hole drilling process by the YAG THG laser and fine interconnection technology using conductive copper paste; and fine layer fabrication by the transfer process. The technologies display the following features: high wiring density by the Fine Via on Via structure; film insulator with high heat resistance and low CTE for a high reliability joint between the bare chip and the substrate; good impedance control for the high frequency circuit; and a flat surface and high heat resistance for the bare chip mounting. The ALIVH-FB substrate is very suitable for the high pin count bare chip direct mounting.