Issue link: https://iconnect007.uberflip.com/i/1248324
MAY 2020 I PCB007 MAGAZINE 63 The sintered connection adds b-stage dielec- tric and sintering paste between two complet- ed PTHs. The sinter paste is cured during a lamination cycle, as is the surrounding B-stage dielectric. This results in a permanent bond between the PCBs. Since this bond is complet- ed with a similar B-stage dielectric as to what is included in each of the completed PCBs, it typically will result in a thermally robust bond. A cross-section example of this via connection is shown in Figure 3. Figure 4 shows a PCB completed in this process. The Samtec Z-Ray© connector that was used is composed of beryllium copper contacts as- sembled into a 0.040" FR-4 substrate. These contacts are designed at the same pitch as the top and bottom of our test vehicle, and when compressed, make the electrical connection. Since this is a connector, this solution does not form a permanent bond; therefore, it is removable. A Z-axis view and cross-section depiction are shown in Figures 5 and 6, re- spectively. The Plastronics connector utilizes their HPin technology, which is composed of BeCu and then Au-plated with a stainless steel spring for compression. These are assembled in- to an 0.040" substrate with 0.10 to 0.15 mm pin length above the surface on either side. This solution also does not form a permanent bond. The top and bottom views are shown in Figures 7 and 8. Figure 4: Sintered PCB. Figure 3: Sinter bond cross-section. Figure 5: Z-axis view of Samtec Z-Ray© connector.