Special PCB

Special PCB : Heavy copper, Extra thin, High TG, RF Board

Extra Thin PCB

This extra thin printed circuit means the thickness of printed circuit board is more thin than normal PCB. For most of FR4 PCB, Min thickness is 0.3mm or 0.4mm, whatever it is 1L or 2L. For 4L, it will be more about 0.6mm.

But sometimes, limited to space or margin, or needed by design purpose, people needs extra thin such as 0.25mm, 0.20mm, or even 0.15mm board, so that PCB can be used in such as SIM card, sensor card, and so on. Extra thin FR4 PCB can be bendable similar like a flexible circuit, but more rigid, and cost will be lower, comparing with the same copper traces.

  • Base material: FR4
  • Board Thickness: 0.1mm~0.3mm(0.004"~0.012")
  • Copper thickness: 0.5 OZ, 1.0 OZ
  • Outline: Routing, punching, V-Cut
  • Soldermask: Bare/White/Black/Blue/Green/Red Oil
  • Legend/Silkscreen Color: Black/White
  • Surface finishing: Immersion Gold, HASL, OSP
  • Max Panel size: 600*500mm(23.62"*19.68")

For extra thin PCB, we can make it at 0.15mm, 0.20mm, 0.25mm, 0.30mm, with or without the soldermask, and copper thickness 1/2OZ, 1OZ.

  • Base material: FR4/Aluminum
  • Copper thickness: 4 OZ~10 OZ
  • Extreme Heavy Copper: 20~200 OZ
  • Outline: Routing, punching, V-Cut
  • Solder mask: White/Black/Blue/Green/Red Oil
  • Surface finishing: Immersion Gold, HASL, OSP
  • Max Panel size: 580*480mm(22.8"*18.9")

Heavy Copper Board does not have a set of definition per IPC. According to PCB industry, however, peopel generally use this name to identify a printed circuit board with copper conductors 3 oz/ft2 - 10 oz/ft2 in inner and/or outer layers. And Extreme heavy copper PCB refers to 20 oz/ft2 to 200 oz/ft2 printed circuit board.
Heavy copper normally used for a various products but not limited to: high power distribution, heat dissipation, planar transformers, power convertors, and so on.

Heavy Copper PCBS

The minimum width and thickness of a heavy copper PCB conductor is determined primarily on the basis of the current carrying capacity required and the maximum permissible conductor temperature rise. A circuit board trace, depending on its size and manufacturing process, may not be rectangular in shape. Heavy copper conductors can significantly add to the overall board thickness. Additive (plating) processed are preferred to subtractive (etching) processes but are more expensive). Typical conductor width/spacing/thickness tolerance is +/-20%, although tighter

RF Boards

RF board stands for Radio Frequency Printed Circuit Boards. The frequency for RF board is normally between 300MHz ~ 3GHz, or much bigger, so normally FR4 board cannot meet the requirements, so we need to use special material to achieve the high frequency and we named this kind of boards as RF boards. RF board is excellent in high frequency performance due to its low dielectric tolerance and loss of material.
The fabricate process is similar like FR4, but the copper plating is more complex than FR4, because material characteristics, it’s much harder to metalize the through hole (copper plating), and other process is complex than FR4, so need unique handling method and experienced workers.

  • RF board is ideal for applications with higher operating frequency requirements. Right now, we normally use following material:
  • RF board is ideal for applications with higher operating frequency requirements. Right now, we normally use following material: Rogers. (Copper from 1/4 OZ to 2 OZ). Click here for PDF file for "Rogers-High-Frequency-Circuit-Materials" such as RO4233, RO4 350, RO4003, and so on.
  • PTFE (Dupon Telfon)


Tg means Glass Transition Temperature. As flammability of printed circuit board (PCB) is V-0 (UL 94-V0), so if the temperature exceeds designated Tg value, the board will changed from glassy state to rubbery state and then the function of PCB will be affected.

If working temperature of your product is higher than normal (130-140C), then have to use high Tg material which is > 170C. and popular PCB high value are 170C, 175C, and 180C. Normally the PCB Tg value should be at least 10-20C higher than working temperature of product. If you 130TG board, working temperature will be lower than 110C; if use 170 high TG board, then maximum working temperature should be lower than 150C.