The protection of through vias within PrintedWiring Boards (PWB) has evolved from limited use to common practice. Technology has evolved where via fabrication techniques and protection methodologies need to be defined to allow current designs to be manufacturable at an acceptable yield and cost. Numerous techniques and objectives exist, and will be discussed in this document. This document is the product of the IPC D-33d Via Protection Task Group and has been developed to provide guidance for the designer and fabricator on how via protection should be approached as well as guidance on how via protection should be specified in procurement documentation.

Purpose This guideline provides PWB designers, fabricators and/or users with information on existing methods for the protection of vias on printed boards. In addition to detailing some of the advantages of via protection, production and material issues are given to aid the user in evaluating the benefits and concerns for each type of protection.