Common HDI Issues


Cost
SFS is tied into some of the largest materials suppliers in the world, and is regularly studying new materials and methods to help save costs. We have in-house drilling machines that utilize the latest in PCB Via Formation technology including linear X, Y, and Z drives, contact drilling sensing systems, and latest PLC instrumentation.

These advancements combine to allow for only a 0.5 mil z-axis tolerance, which enables us to use mechanical drilling for vias down to 4 mils in diameter and 4 mils deep (1:1 aspect ratio) without the use of more expensive, and rare, laser drilling systems. Should you have blind via designs that are more aggressive than can be drilled on these latest technology mechanical drilling systems, we also have an in-house CO2 / YAG laser drilling system.

Voids
Desmear / Deash
To insure that blind vias are properly desmeared and deashed (if laser drilled), we utilize a two-step desmear process. This process first requires that the panels be submitted to a plasma conditioning process in our Plasma System. We then process through a chemical desmear that has been optimized for micro- and blind vias. This line has been outfitted with long-stroke agitation and flight bar vibration to enhance fluid movement and prevent air bubble entrapment.

Copper Plating
Further, our copper plating lines have been outfitted with long-stroke agitation and flight bar vibration to enhance fluid movement and prevent air bubble entrapment. By 2015, we expect to have installed Reverse Pulse Plating in our facility to plate even the most aggressive designs, and also to copper fill these so that your blind vias can also be used as via-in-pad technology.

Inter-Layer Registration
We have modified the dynamic tooling systems we use to register rigid-flex buildups for use with thin core rigid (and flexible) applications typically found with HDI buildups.  The multiple tooling hole and registration options at layup, drill, and image allow us to hold optimal registration even with buildups that require 4 or more lamination cycles.