Build Up

In this simple example of a build-up technology board, we start with a core of Thermount material (process compatible with any material) .005” thick. We then laser drill .003” holes which will act as buried vias between layers 2 & 3. This core, 2 and 3 will now be processed as a standard double- sided board. At this point we laminate copper foil to the top and bottom of the core utilizing .003” Thermount prepreg material (virtually any bonding material is acceptable). This acts as the insulating layers between layers 1 and 2 and layers 3 & 4.

After lamination we are ready to form our laser vias between layers (1 and 2) and (3 and 4). In order to maintain near perfect registration for these vias to their appropriate stop pads it is necessary to laser oblate the material between layers (1 & 2 and 3 & 4) in order to reveal four fiducials located at all four corners of the panel.

The laser system then acquires the fiducials with its vision system, performs a best-fit algorithm, and based on the movement of the material of core 3 & 4 the machine scales the drill file, and laser drilles the holes.

* Note that this designs density allows for a staggered approach. By utilizing a dog bone shaped pad to act as the stop pad for the laser holes.

The ideal shaped blind via hole is demonstrated in the photo to the left, which exhibits a tapered appearance, which provides excellent solution movement and results in perfect plating thickness.

After plating and etching we are now ready to repeat this process and to build up additional layers if nessesary.

*Please ask your sale engineer how this technology can be applied to your next project!