High-Density Board Fabrication Techniques

A variety of construction methods can be used to form high-density printed-circuit boards. The electrical and mechanical requirements of a design strongly influence the choice of processes used to produce the finished product. The introduction of physically large high-density boards required the development of many new processes, several of which are critical to the electrical performance of the composite. In this paper the process sequence employed in the fabrication of the 3081 high-density board is described, with particular emphasis on the selection of the critical processes used in its manufacture. The 3081 registration system is also discussed, and a new method for merging through-hole location data with the data representing the location of the conducting layers is presented.