Sierra Assembly provides advanced Bare PCB Manufacturing Services, serving as a trusted circuit board manufacturer for mission-critical electronics across aerospace, defense, medical, industrial automation, energy, telecommunications, semiconductor equipment, and high-speed computing. As an AS9100-certified, ISO 9001-compliant, and ITAR-registered electronics manufacturer, we deliver Class-3 quality bare printed circuit boards (PCBs) that meet stringent reliability, traceability, and regulatory requirements.
Our California-based manufacturing support enables faster engineering collaboration for OEMs in Los Angeles, Orange County, Riverside, San Bernardino, San Jose, San Francisco, Santa Rosa, Oakland, Fremont, and Fresno, key hubs for electronics design, aerospace, medical, and semiconductor innovation.
What Is a Bare PCB?
A bare PCB is a fully fabricated but unassembled printed circuit board containing conductive layers, vias, and copper traces, without any components mounted. Bare PCBs are the foundation for high-performance electronic assemblies, requiring precision in stack-up design, copper uniformity, material selection, and electrical testing.
Sierra Assembly manufactures bare PCBs with a focus on dimensional accuracy, signal integrity, and long-term performance, ensuring your boards are production-ready for SMT, wave soldering, and complex assembly workflows.
Advanced Bare PCB Fabrication Capabilities
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1–32 layer rigid PCBs
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High-Tg FR-4, halogen-free, and high-temperature laminates
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PTFE, ceramic-filled, and low-loss dielectric options
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Hybrid stack-ups combining FR-4 and advanced RF materials
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Laser microvias, blind & buried vias, stacked & staggered via architectures
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Via-in-pad (VIPPO) technology for BGA-dense layouts
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Copper weight from 0.5 oz to 6 oz
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Trace width/spacing down to 3 mil (or tighter upon review)
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Tight impedance control with TDR validation
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Controlled dielectric thickness for RF and SERDES designs
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ENIG / ENEPIG, Immersion Silver / Immersion Tin, HASL leaded / lead-free, Hard & soft gold plating
Quality, Compliance & Reliability Controls
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Automated Optical Inspection (AOI)
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Flying probe or fixture-based electrical testing
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Microsection analysis for plating thickness & hole quality
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Solderability testing
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Dimensional inspection & impedance validation
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X-ray inspection available during assembly stage
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Manufacture to IPC Class 2 and Class 3 standards
Industries Relying on Sierra Assembly’s Bare PCBs
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Aerospace avionics and flight controls
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Defense communication systems
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Medical imaging, wearable health devices
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Semiconductor test & measurement equipment
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Industrial robotics and automation
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Automotive EV systems
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5G and high-speed networking hardware
California’s Leading Engineering Hubs Trust Sierra Assembly
Aerospace & Defense Corridor - Los Angeles, Orange, San Bernardino
OEMs in Southern California depend on our ITAR-registered, Class-3 bare PCB fabrication for applications such as radar systems, flight electronics, navigation control boards, and ruggedized communication modules.
Silicon Valley Semiconductor & Networking Cluster - San Jose, Fremont, Santa Rosa
Our advanced multilayer bare PCBs support high-speed digital architectures, RF modules, and semiconductor tools extensively used in Silicon Valley’s innovation ecosystem.
Medical & Instrumentation Engineering Centers - San Francisco, Oakland, Fresno
Hospitals, research labs, and medical hardware companies rely on our precision bare PCBs for diagnostic instruments, infusion systems, patient monitoring equipment, and life-critical technology.
Why Leading California OEMs Choose Sierra Assembly
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AS9100 & IPC Class 3 fabrication expertise
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Rapid DFM & engineering consultation
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Controlled impedance and RF-ready stack-up modeling
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Tight tolerances for high-density designs
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Full traceability and documentation packages
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Quick-turn prototypes and scalable production
Request a Quote
Submit your Gerber files, stack-up details, or impedance requirements, and our engineering team will provide a full manufacturability review and accurate quote
