Via processing options for MCM-D fabrication: excimer laser ablation vs. reactive ion etching

The use of reactive ion etching and excimer laser ablation processes for the etching of vias through thick layers of dielectric (up to 25 μm thick) in multichip module fabrication is evaluated. A comparison of possible masking schemes is presented. Typical etch results obtained by these techniques are shown and compared. A throughput analysis of these two via fabrication techniques for use in a high-volume multichip module substrate facility is presented. Results obtained suggest that laser processing is a viable alternative to reactive ion etching for multichip module substrate via fabrication