RIGID-FLEX BOARD
A rigid-flex is a board that combines rigidity and flexibility, processing both the rigidity of rigid board and flexibility of flexible board.
Capability Roadmap
| Item | Flex ‐ Rigid | Regal | Semi‐Flex |
| Figure |  |
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| Flexible Material | Polyimide | FR4 + Coverlay(Polyimide) | FR4 |
| Flexible thickness | 0.025~0.1mm (Exclude copper) | 0.05~0.1mm (Exclude copper) | Remained Thickness: 0.25+/‐0.05mm (Dedicated Material: EM825(I)) |
| Bending angle | Max 180° | Max 180° | Max 180°(Flex layer≤2) Max 90°(Flex layer>2) |
| Flexural Endurance IPC‐TM‐650,Method 2.4.3. | <1000 cycle | < 25 cycle | NA |
| Bending Test 1) Mandrel diam:6.25mm | <10K cycle (Bending Angle:180°) | <500 cycle (Bending Angle:180°) | <10 cycle (Bending Angle:180°) |
| Application | Flex to install & Dynamic(Single side) | Flex to install | Flex to install |
| Surface Finish | Typical Value | Supplier | |
| OSP |  |
0.2~0.6um; 0.2~0.35um | Enthone Shikoku chemical |
| ENIG |  |
Au:0.03~0.12um, Ni :2.5~5um | ATO tech/Chuang Zhi |
| Selective ENIG |  |
Au:0.03~0.12um, Ni :2.5~5um | ATO tech/Chuang Zhi |
| ENEPIG |  |
Au : 0.05~0.125um, Pd : 0.05~0.125um,Ni :5~10um | Chuang Zhi |
| Hard Gold |  |
Au:0.2~1.5um , Ni : min 2.5um | Platec |
| Soft Gold |  |
Au:0.15~0.5um , Ni : min 2.5um | EEJA |
| Immersion Tin |  |
Min: 1um | Enthone / ATO tech |
| Immersion Silver |  |
0.15~0.45um | Macdermid |
| HASL & Lead free HASL (OS) |  |
1~25um | Nihon Superior |
Au/Ni Type
Gold plating can be divided into thin gold and thick gold according to thickness. Generally, gold below 4u”(0.41um) is called thin gold, while gold above 4u” is called thick gold. ENIG can only make thin gold, not thick gold. Only gold plating can make both thin and thick gold. The maximum thickness of thick gold on flexible board can be over 40u”. Thick gold is mainly used in working environments with bonding or wear resistance requirements.
Gold plating can be divided into soft gold and hard gold by type. Soft gold is ordinary pure gold, while hard gold is cobalt containing gold. It’s precisely because cobalt is added that the hardness of the gold layer greatly increases exceeding 150HV to meet the wear resistance requirements.
| Material Type | Properties | Supplier | |
| Rigid Material | Normal Loss | DK>4.2, DF>0.02 | NanYa / EMC / TUC / ITEQ / ShengYi / Isola / Doosan etc. |
| Middle Loss | DK>4.1, DF:0.015~0.02 | NanYa / EMC / TUC / ITEQ etc. | |
| Low Loss | DK:3.8~4.1, DF:0.008~0.015 | EMC / NanYa / TUC / Isola / Panasonic etc. | |
| Very Low Loss | DK:3.0~3.8, DF:0.004~0.008 | EMC / Panasonic / Rogers / TUC / Isola / ITEQ / NanYa etc. | |
| Ultra Low Loss | DK<3.0, DF<0.004 | Rogers / TUC / ITEQ / Panasonic / Isola etc. | |
| BT | Color：White / Black | MGC / Hitachi / NanYa / ShengYi etc. | |
| Copper Foil | Standard | Roughness(RZ)=6.34um | NanYa, KB, LCY |
| RTF | Roughness(RZ)=3.08um | NanYa, KB, LCY | |
| VLP | Roughness(RZ)=2.11um | MITSUI, Circuit Foil | |
| HVLP | Roughness(RZ)=1.74um | MITSUI, Circuit Foil | |