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Via Tenting: a term is used by many fabrication shops. Tenting means covering via with solder mask. This is a requirement for any vias under a BGA to prevent solder bridging short circuits during the assembly process. Capped Vias: a technology that allows to design VIP (via in pad) because of flatness surface. Copper via filling as resin via filling plus copper capping are the two main technological solution available today. Solder Mask Covered: a pad or via (via tenting) is covered with solder mask. Mask Plugged Via: for this specific measures are taken to ensure the via is plugged and sealed with mask and the annular ring is covered. A common application for this is on a BGA design where vias are commonly found in very close proximity to the BGA’s SMD pads. The concern is during assembly, solder will wick away from the intended pad and flow down the via creating poor or non-existent solder joints. Via Filling: There are two types of via filling - Non Conductive
- Conductive
Conductive Fill: generally, a conductive filled via will be used when heat or a large amount of current needs to be carried from one side of the board to another. These can be found under chips that will be giving off a lot of heat where overheating is a concern. Non Conductive: usually done to prevent solder or other contaminants from entering the via or provide structural support for a copper pad covering the open hole in the case of a Via In Pad. Non-Conductive fill is another term for mask plugged vias. Via encroaching: a technique that is often adopted due to concerns about the presence of solder mask material under the device. This technique allows solder to flow down the via, but restricts the migration of the solder across the bottom plane of the board. |