Issue link: https://iconnect007.uberflip.com/i/972396
As is the case with any multilayer construc- tion, core thickness must be provided with the assumption that copper is clad on at least one surface. The core thickness is generally under- stood to be the thickness of the dielectric mate- rial between the copper layers. The core mate- rial can be a simple single-sided piece of cop- per clad polymer, or it can be clad with copper on both sides. Many different core thicknesses are commonly available for flexible circuits, but the most common is 75 mm, typically com- prised of 25 mm of base polymer (e.g., poly- ALL RIGID WITH FLEX BONDED TOGETHER FLEX AREA LAYER 1 LAYERS 2/3 LAYERS 4/5 LAYERS 6/7 LAYER 8 RIGID CORE NO-FLOW PREPREG NO-FLOW PREPREG RIGID WITH FLEX BELTS FLEX AREA RIGID WITH FLEX BELTS LAYER 1 LAYERS 2/3 LAYERS 4/5 LAYERS 6/7 LAYER 8 RIGID COVERLAYER FLEX CORE WITH COPPER FLEX CORE WITH COPPER COVERLAYER COVERLAYER BOND PLY FLEX CORE WITH COPPER BOND PLY FLEX CORE WITH COPPER RIGID CORE RIGID CORE RIGID CORE NO-FLOW PREPREG NO-FLOW PREPREG ALL RIGID WITH FLEX BONDED TOGETHER NO-FLOW PREPREG NO-FLOW PREPREG NO-FLOW PREPREG NO-FLOW PREPREG NO-FLOW PREPREG NO-FLOW PREPREG NO-FLOW PREPREG NO-FLOW PREPREG RIGID RIGID RIGID FLEX CORE WITH COPPER FLEX CORE WITH COPPER COVERLAYER COVERLAYER COVERLAYER COVERLAYER COVERLAYER Figure 2: Bonded vs. unbonded flex. areas. 54 FLEX007 MAGAZINE I APRIL 2018