Specialist rigid-flex/HDI: FlexPCB.com, Rigid-Flex International
Prototype through production / competitive sourcing: Aegis, APTPCB, AtlasPCB, Sunshine
Very advanced HDI rigid-flex: Multek, TTM, DYCONEX are worth contacting first because their published capabilities explicitly address sophisticated HDI/rigid-flex structures.
If you're sourcing for an actual program, I can also narrow this to U.S.-based suppliers, Asia suppliers, low-volume prototype suppliers, or high-volume production suppliers, and put together a comparison of minimum trace/space, microvia size, layer count, certifications, typical MOQ, lead time, and manufacturing location.
Here is a curated list of top-tier PCB suppliers and manufacturers that specialize in advanced rigid-flex and High-Density Interconnect (HDI) technologies, ranging from global high-volume producers to specialized quick-turn prototype houses.
Global Leaders & High-Volume Manufacturers
TTM Technologies: One of the largest global printed circuit board manufacturers, TTM offers robust capabilities in advanced multilayer rigid-flex (Type 4) and complex HDI structures. They heavily support high-reliability sectors including aerospace, defense, and high-end commercial tech.
Sanmina: Known for extreme engineering capabilities, Sanmina specializes in complex 3D rigid-flex designs, fine-line inner layers, and sophisticated HDI tech (including microvias, stacked vias, and sequential lamination). They are a primary resource for mission-critical medical, defense, and aerospace infrastructure.
Zhen Ding Tech Group: A massive global manufacturer based in Taiwan with massive scale in flexible printed circuits (FPC), rigid-flex boards, and advanced HDI/substrate-like PCBs (SLP) tailored for consumer electronics, mobile devices, and networking gear.
Unimicron Technology Corporation: Another premier Taiwan-based global provider specializing in high-end HDI, multi-layer rigid-flex, and IC substrates servicing high-speed computing and communication industries.
Specialized & Quick-Turn Prototype Suppliers
Innovative Circuits, Inc.: Based in Alpharetta, GA, they operate as a quick-turn, high-tech prototype fabricator specifically focusing on advanced rigid-flex and flex circuits for defense, aerospace, and medical applications. They maintain AS9100D and ITAR certifications.
Cicor Group: Headquartered in Switzerland, Cicor excels in high-density integration, ultra-HDI rigid-flex configurations, and specialized miniaturized packaging for medical, industrial, and aerospace systems.
If you can share whether you need quick-turn prototyping or mass production , as well as any specific certifications (like ITAR or AS9100) required for your project, I can help narrow down the best fit.