Issue link: https://iconnect007.uberflip.com/i/1419905
OCTOBER 2021 I PCB007 MAGAZINE 73 the majority have excellent chem- ical exchange for normal plating baths. e new alternative drill/ router bits have successfully cre- ated channels of 0.1 mm with straight walls and no burring. Fig- ure 3 shows various blind channel depths plated with conventional plating equipment. Figure 4 shows plating results with respect to the slot length and slot depth. Note that for these tests, NextGIn used plating processes at standard parameters and chemis- try types. e method of plating was electroless copper followed by a panel plate to the required cop- per thickness in the slot targeting a thickness of 25 µm. Fabrication Process Figure 5 presents the views of the VeCS fab process, starting with a conventional through-hole multi- layer. e process has eight steps: 1. Create slot 2. Plate slot 3. Alignment in BGA pin field 4. Resin fill PR slot and PR stencil 5. Drill CR slots 6. If vertical traces are going to be used, drill BR slots 7. BR/CR stencil 8. Resin fill BR/CR slot In Step 1, aer drilled vias are completed, the primary cross-rout (CR) slots are put in. Here, a spe- cial drill/router bit uniquely suited for this operation is used. Much work and experimentation were conducted to perfect an ideal drill/ router bit for this task. en in Step 2, metallization and copper plat- ing are performed. In Steps 3 and 4 the resin is now used to fill the CR Figure 3: Creating and plating the blind channel (slot) is the key feature of VeCS-2 but is within the capability of any high- performance PCB fabricator 3 . (Source: NextGIn) Figure 4: Plating thickness as a function of slot depth and length 3 . (Source: NextGIn)