Issue link: https://iconnect007.uberflip.com/i/1104607
88 PCB007 MAGAZINE I APRIL 2019 Article by Joan Tourné NEXTGIN TECHNOLOGY Sequential lamination, as it is used today in high density interconnect (HDI) and derivative technologies, is constrained by the fact that one cannot plate a blind hole deeper than the diameter of the hole. A larger hole allows pro- cesses to plate deeper. In fact, this manufactur- ing constraint has made it a challenge even to reliably plate and process blind holes up to a 1:1 aspect ratio (AR). NextGIn Technology, a technology company based in Helmond, the Netherlands, took up the challenge to redesign PCB lamination tech- niques to be easier to fabricate, to increase per- formance, and to lower fabrication cost in com- parison to current technologies. The constraint set by NextGIn Technology was to use only cur- rent fabrication processes and tools available in the board shops. Using no new equipment, NextGIn set out to develop new processes for existing facilities. To do this, NextGIn needed to rethink the possibilities for what can be do- ne with the capital equipment and processes. NextGIn has named this new process "vertical conductive structure" or VeCS. Traditional manufacturing constraints stip- ulate that to plate deeper, a larger diameter hole is required. And yet, there is often no ad- ditional space in the board design for bigger holes. Perhaps the shape of the hole can be rethought. An oblong hole or slot, for example, would allow the hole to be cut up in multiple structures. The limit to plating is the size of the holes. One can plate a blind hole as long as you respect the AR of 1:1. Even the 1:1 AR can be a challenge to plate reliably, but to fit it into the current design footprint is not an option. Cutting holes into multiple sections has been on the research and development agenda of the interconnect industry for some decades but work to turn the technique into a process has not been successful to date. NextGIn started by modifying the shape of the hole. An oblong shape structure was created that was broken into multiple sections to form the contacts. In the initial plating experiments, this oblong