Printed Circuits boards without Ferro-magnetic materials

For researchers, engineers, and scientists conducting experiments that require utmost accuracy, the presence of magnetic materials in printed circuit boards (PCBs) or component submounts can be a major source of concern. Our ceramic circuits use no ferro-magnetic materials in the metalization processes but there is one metal that will need to be avoided when a surface finish is needed: Nickel (Ni).

This common ingredient in PCB surface finishes like ENIG (electroless nickel, immersion gold) or ENEPIG (ENIG + electroless palladium), is known for its Ferro-magnetic properties, and its presence can potentially interfere with sensitive measurements and alter the outcomes of experiments.

Also, in sensitive industrial applications like medical equipment or aerospace systems, where magnetic interference can cause malfunctions or safety hazards, nickel-containing PCBs are often considered unsuitable and preferably avoided.

Illustration: typical PCB stack up with a nickel layer that serves as an intermediate layer between copper and (palladium &) gold

immersion tin finish on a AlN LED PCb

Photo: Immesion tin on a Aluminium nitride LED PCB

Photo: Alumina circuit board with Direct immersion Gold (DIG) surface finish

Non-Magnetic alternatives for PCB Surface Finishes @ CERcuits

Fortunately, we offer several non-magnetic alternatives to nickel that can provide the necessary protection for PCBs while minimizing the risk of magnetic interference. Here are some of the most suitable options:

Immersion Tin (Immersion Sn): Immersion tin is a cost-effective and widely used finish that offers solderability and corrosion resistance. The thin tin layer effectively protects the copper traces while remaining virtually non-magnetic.

Standard thickness: Sn >0.5um

Immersion Silver (Immersion Ag): Immersion silver provides a slightly thicker layer of protection compared to ISn, offering enhanced corrosion resistance and wire bonding capabilities. However, it is important to note that silver is more prone to oxidation, especially in high-sulfur environments.

Standard thickness: Ag 0.05-0.1um (alternative 0.15-0.4um also available)

Electroless Palladium Immersion Gold (EPIG): EPIG is a versatile surface finish that combines the benefits of palladium and gold. The palladium layer provides excellent corrosion resistance and acts as a barrier against gold diffusion, while the gold layer ensures excellent solderability and (gold) wirebondeability.

note that the finish looks a little more rough and bright yellow as it is missing the (shiny) nickel layer underneath.

Standard thicknesses: Pd 0.1-0.2um & Au 0.1-0.2um

Direct Immersion Gold (DIG): DIG offers the thickest gold layer of all the non-magnetic options, so it can withstand diffussion and migration for a long time while allowing good wirebondeablity and solderability. It is also suitable for very tight spacing and widths. It is therefore our standard finish for circuits below 75um width and spacing.No that

Note that also DIG appears more rough and yellow, similar to EPIG.

Standard thickness: Au 0.1-0.3um

Ordering ceramic circuits with no Ferro-magnetic finish

CERcuits is making it easy to order ceramic circuits with the alternative surface finishes which do not use any nickel or other magnetic material.

Simply select one of the finish listed above in our online quoting tool from the drop down menu and that is it. (see screenshot). Both our alumina 96% as our aluminum nitride circuit solution have the nickel free finishes as a standard option.

Any Question or would to discuss your magnetic-free electronics project. Do not hesitate to contact us.

 

Alumina (Al2O3 96%) - Online Quote Aluminium Nitride (AlN) - Online Quote
Ceramic-pcb online quote tool - Surface finish

screenshot: selecting your non-magnetic finish at ceramic-pcb.com is easy. Simply select one of the non-nickel finishes from the drop down menu.

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