Glossary Table H
| HDI: High Density Interconnect. |
| Halo Effect: Minor delamination of the substrate material, resist, or laminate around holes. |
| Heat Sink: A method of conducting heat away from an area. |
| Hermetic: Airtight sealing of an object. |
| Hole Breakout: Condition where a hole is not completely surrounded by the land. |
| Hole Density: The number of holes per unit area on a PCB. |