IPC-2226A, Sectional Design Standards for High Density Interconnect (HDI) Printed Boards is used in conjunction with IPC-2221B. The IPC-2226A standard establishes requirements and considerations for the design of high density interconnect (HDI) printed boards and microvia technology. Revision A constitutes a substantial update to the document, with an all new color key for HDI constructions, new coverage of routing density factors and a complete rebuild of feature size recommendations, including aspect ratio, capture and target land sizes. Almost every graphic in Sections 3, 5 and 9 has been revised and/or supplemented with new graphics addressing various microvia formation processes and HDI constructions