PTFE / RF MicrowaveVoids
Desmear and Ash
To insure that vias are properly desmeared and material hole walls activated, we utilize a two-step desmear process. This process first requires that the panels be processed through a chemical desmear that has been optimized for microvias 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. The panels are then submitted to a plasma conditioning process in our March Plasma System. PTFE materials contain Teflon, which has the primary property of not allowing other materials to adhere to it. As such, copper plating is not possible without plasma activating the surfaces of the hole wall.
We have studied a large extent of various PTFE systems and core thickness from Rogers, Taconic, and Arlon to determine scale factors in standard processing in combination with copper retention percentages. A key instrument in these studies is the use of the PerfecTest system and resulting knowledge database. We consult this database each time a new part number is produced.
Automatic Alignment Imaging Systems
We have installed 4-camera automatic alignment imaging systems. These units utilize a 4-camera system to align the top and bottom artwork to within 0.5 mils. They then make micro adjustments to the panel position for best fit panel-to-artwork alignment.