Definition

Build-up refers to the process of adding layers to a core PCB through sequential lamination, used in HDI construction. Build-up layers are typically thinner than conventional layers and use laser-drilled micro-vias for inter-layer connection. Common build-up materials include RCC (resin-coated copper) and thin prepreg. Build-up layers can be added symmetrically (equal layers each side) or asymmetrically. Each build-up layer requires lamination, laser drilling, and plating cycles, adding to cost and cycle time.