MCM-D via generation by scanning laser ablation

An excimer laser based scanning ablation process has been developed and is successfully being used in the fabrication of MCM-D (deposited dielectric) type substrates. In this process, a 1 to 4 /spl mu/n thick patterned conformal metal ablation masking layer is formed using either a subtractive or semi-additive process. Substrates are placed on the precision X-Y stage of a scanning laser ablation (SLA) system equipped with a 75 watt, 308 mn XeCl industrial excimer laser and scanned. Vias with sidewall angles of 78 to 84 degrees are produced with minimal thermal damage. Substrate throughputs in excess of 45 - 4' x 4" parts per hour of 25 /spl mu/m thick dielectric layers are possible with this via generation process.