PCB007 Magazine

PCB-Apr2015

Issue link: https://iconnect007.uberflip.com/i/490885

Contents of this Issue

Navigation

Page 23 of 76

24 The PCB Magazine • April 2015 HIGH-DENSITy INTERCONNECTS: ENABLING THE INTELLIGENCE OF THINGS continues FeAture when stacking. Stacked microvia can be com- bined with buried and thru-hole technology (Figure 1). Staggered microvias are laser drilled offset to the other microvia in adjacent layers creating a staggering pattern of microvias between lay- ers in the PCB. The microvias do not necessarily need to be copper filled and are often resin filled from the adjacent dielectric layer. Staggered mi- crovia can be combined with buried and thru hole technology (Figure 2). Every layer interconnect connection (ELIC) allows for dynamic connection between any two layers within the circuit layout. This flex- ibility optimizes useable area for dense compo- nent placement and provides a higher level of circuit density for complex routing challenges. ELIC employs a method of using stacked micro- vias on every layer. This process starts with an ultra-thin core that has microvias drilled and solid copper filled as the base. Using this initial core, a sequential lamination is use to add ad- ditional dielectric layers with laser drilling and copper via filling as required on both sides to achieve the final stackup (Figure 3). This allows for the unique process of start- ing and ending any routing requirement on any layer and opens routing channels and pro- vides the ability to reduce the overall thickness of the PCB. ELIC design guidelines follow the same structures as for stacked microvia, but provide higher internal routing density due to the elimination of buried through-hole vias in the initial sub buildup, and eliminating holes Table 1: Typical stackup structures of HDI technology.

Articles in this issue

Archives of this issue

view archives of PCB007 Magazine - PCB-Apr2015