Home » Products & Services » Flex & Rigid-Flex Circuit Boards

Flexible circuit boards, often known as “flex” boards are often using in electronics that need to bend.  Flip phones, laptops and other every-day electronics that need to move or “flex” use flexible circuit boards.  Common Flex material use in our construction are DuPont Kapton and along with polyimide materials if required.


Single/Double Sided Flex PCBs

  • Single-Sided flex boards are usually applied to applications with dynamic flexing, folding and forming.  Single-Sided flex construction are very thin in nature, usually .004-.008″.  They only exhibit one conductor layer.
  • Double-Sided flex boards are usually applied to ground and power plane applications that require surface mount assembly on either one or both sides.

Multilayer Flex PCBs

  • Multilayer Flex boards also are used in ground and power plane applications with controlled impedance and dielectric withstanding.

Rigid-Flex PCBs

  • Rigid-Flex boards inherit both rigid and flexible layers of circuits.
  • Rigid-Flex boards are more costly than multi-layer boards.
  • Usual application for aerospace, military and medical devices.

Microwave Rigid-Flex Circuits (R&D)

  • EPC is leading the way with the innovative use of latest high performance material systems to provide design engineers with new design paradigms.
  • Our use of thin Liquid Crystal Polymer materials in rigid-reflex, rigid and flex multilayer constructions is unequalled in the industry.
  • Used together with standard high frequency materials, EPC can supply microwave rigid-flex constructions that simplify and cost reduce high frequency interconnects, while as the same time enhancing long-term reliability.
  • Our latest innovation is using thin, reinforced PTFE materials along with traditional PTFE based laminates to create rigid-flex microwave interconnects. 


Quality Management Systems

ISO9001:2008 AS9100

Fabrication Specifications

MIL-P-50884 IPC-6013 Classes 2&3

Conformance Testing:

  • Fully equipped Microsection, Metallurgical, Chemical Lab for Process Controls & SPC on major processes
  • Polar Impedance Test & TDR Reports/ Polar-SI6000 Impedance Stack-up Software
  • žXRF Fluorescence Measurements of metallic plating thicknesses
  • Ionic Cleanliness Tester
  • 100% Automated Optical Inspection
  • 100% IPC-D-356 Gerber Net List Test with Flying Probe Electrical Testers
  • Geometric Dimensioning and Tolerancing (GD&T) with Automatic Coordinate-Measuring Machine (CMM)
  • High-Pot Test Available
  • Steam Aging Available
  • Inspection per IPC-600H – Acceptability of Printed Circuit Boards

Documentation (Retained on site for 7 Years or as needed):

  • Certificate of Conformance (CofC)
  • IPC or MIL Checklists
  • Electrical Test Certs
  • Microsection Analysis (if applicable)
  • Material Certs
  • Solder, Coupons, Microsection Samples (upon on request).


Quick-Turn Delivery Times:     Standard Delivery Time – 7  Days

Layers 1 Day 2 Days 3 Days 4 Days 5 Days 6 Days 7+ Days
1-4 Layers
5-16 Layers    
16-20+ Layers    

Standard Panel Sizes **Larger Panel Size Formats Available

Panel Sizes 1-2 Layers 4 Layers 6+ Layers

Technology Roadmap

 (click to download)
Standard Advanced Emerging
Maximum Layer Count 26 36 46
Maximum Board Thickness .200” .250” .300”
Minimum Board Thickness .008” .005” .004″
Board Thickness Tolerance ±10% ±7% ±5%
Maximum Panel Size 18×24 21×24 24×26
Maximum Warp And Twist .010” .005”> .004”>
Maximum Warp and Twist Percentage 1% 0.70% 0.30%
Maximum Probe Card Warp And Twist .005” .003” .0015”
Minimum Line Width / Spacing 1/2 oz Cu .004″ .003″ .002″
Minimum Line Width / Spacing 1 oz Cu .005″ .004″ .003″
Minimum Line Width / Spacing 2 oz Cu .006″ .005” .004″
Minimum Line Width / Spacing 3 oz Cu .007″ .006″ .005″
Maximum Copper Weight 3 oz 6 oz 8 oz
Minimum Base Copper Foil 1/2 oz 1/4 oz 1/8 oz
Minimum Blind & Buried Via Drilled Hole Diameter .010” .008″“ .006″
Minimum Through Hole Via Drilled Diameter .010” .008″“ .006″
Minimum Through Hole Via Annular Ring .006” .005” .004″
Minimum Fab Allowance Pad To Hole Per IPC-2221 .008” .006″ .006″
Plated Through Hole Aspect Ratio 20:01 22:01 25:01
Minimum Plated Thru Hole Tolerance ±. 003” ±. 002” ±. 0015”
Minimum Non-Conductive Via Fill .008″ .006″ .006″
Minimum Conductive Silver Via Fill .008″ .006″ .006″
Minimum SMT Pitch .6mm .5mm .4mm
Minimum BGA, MBGA Pitch .6mm .5mm .4mm
Electrical Testing–Continuity (Ohms) 3 3 3
Electrical Testing–Isolation (Meg Ohms) 10-100 10-100 10-100
Electrical Testing-Isolation (Volts Dc) 40-1000 40-1000 40-1000
Electrical Testing–Minimum Pad Pitch .3mm .3mm .3mm
Minimum Dielectric Thickness .004” .003″ .002″
Controlled Impedance ±10% ±5% ±3%
Differential Controlled Impedance ±10% ±5% ±5%
Soldermask Liquid Photoimageable (LPI)
Black Blue Glossy Green White Red Yellow Green Flat Matted
Legend Ink
Black White Yellow


Nelco N5000
Rogers RO3000 RO4000 RT/Duroid TMM Ultralam XT/Duroid


Common PCB Materials
CEM-1- Made from paper and woven glass which is impregnated with an epoxy resin, this material is good for punching. Improved electrical and physical properties make it suitable for both consumer and industrial electronics.

CEM-3- A composite made of dissimilar core materials, CEM-3 utilizes non woven fiberglass surfaced with woven fiberglass sheets, both impregnated with epoxy resin. Higher in cost than CEM-1, CEM-3 is better utilized for plated through holes and has an apparent usage in personal computers and automobiles.

FR-2- Good for punching, very cheap and flame-resistant, this material can be used in a host of applications where dimensional stability is not required. (i.e. toys and calculators).

FR-4- Constructed of woven fiberglass clothes which are impregnated with epoxy resin or epoxy resin blend, the outstanding electrical, mechanical and thermal properties of FR-4 make it an excellent material, which can be useful in a wide range of applications.

Non-Flame Retardant Flame Retardant
G-10 (Epoxy Woven Glass) FR-2 (Phenolic Cotton Paper)
XXXPC (Phenolic Cotton Paper) FR-3 (Epoxy Cotton Paper)
CEM-2 (Epoxy Cotton Paper/Woven Glass) FR-4 (Epoxy Woven Glass)
CRM-6 (Polyester Woven Glass/Mat Glass) FR-5 (Epoxy Woven Glass)
CRM-8 (Polyester Mat Glass/Glass Veil) FR-6 (Polyester Mat Glass)
CEM-4 (Epoxy Woven Glass/Mat Glass) CEM-1 (Epoxy Cotton Paper/Woven Glass)
CEM-3 (Epoxy Woven Glass/Mat Glass)
CRM-5 (Polyester Woven Glass/Mat Glass)
CRM-7 (Polyester Mat Glass/Glass Veil)

Surface Final Finishes

Final Finishes  Requirements  Supplier
HASL Hot Air Solder Level – Default IPC Class 2 Finish  Tin-Lead 63/37. J-STD-006. Pad coverage.  Florida Cirtech Nitro
LEAD-FREE HASL RoHS Compliant J-STD-006.  Pad Coverage.  Florida Cirtech Nihon
REFLOW  Florida Cirtech Reflow Oil
ENIG Meets IPC 4552. Superior finish to other immersion finishes.  excellent corrosion resistance and mechanical strength for great solderability.  Thickness range 118-230 μin nickel followed by 2-5 μin immersion gold.  Florida Cirtech ENIG
HARD GOLD Meets MIL-DTL-45204 and ASTM B488, Types 1 & 2, Code C.  Hardness: 30-200 Knoop.  Gold purity is a minimum of 99.7%.  Thickness range 5-200 μin.  Most contact fingers require 30-50 μin  Technic Orosene 80RC
SOFT GOLD MIL-DTL-45204 and ASTM B488, Type 3, Code A.  Hardness: 90 Knoop maximum.  The Gold purity is a minimum of 99.9%.  Thickness range 10-100 μin.  Techni-Gold 434HS
SMOBC Soldermask over bare copper.  No Final Finish  N/A
BARE GLASS Just Woven Glass – Bare Laminate  N/A
ELECTROLESS NICKEL  Meets AMS-QQ-N-290 and ASTM 2424. Thickness range 100-250 μin.  Florida Cirtech ENIG
IMMERSION SILVER  Meets IPC 4553, AMS-QQ-S-365 & ASTM-B-700. Thickness Range 4-16 μin.  MacDermid Sterling Silver
IMMERSION TIN  Meets IPC-4554.  Thickness Range 20-50 μin.  Enthone ORMECON
ELECTRODEPOSITED TIN  Meets AMS-P-81728 Thickness Range 300-500 μin Enthone
TIN-LEAD  Meets AMS-P-81728  Thickness of 300 μin.  OMG
TIN/NICKEL  TIN then Nickel  N/A
OSP/ENTEK  4-24 μin.  OMG

Valued Added Capabilities

  • Heatsink and Bonding
  • V-Scoring
  • Countersinking
  • Counterboard vias
  • Edge plating
  • Conductive & non-conductive via fill
  • Laser blind vias
  • Laser skived access features
  • Extensive Milling & Machining.

PCB Processes