What are the advantages of using immersion silver?

Provides a lead -free finish

Deposition is flat and uniform making it compatible with high density, fine pitch designs

Soldering Sterling™ results in a copper-tin intermetallic solder joint

What immersion silver product does Hunter Technology use?

Hunter Technology uses Sterling™ Metallic Solderability Preservative manufactured by MacDermid, Incorporated.

Is Sterling™ a drop-in replacement for HASL?

It should be, with one exception. If your HASL boards typically have a thick solder coating, switching to immersion silver can cause a stencil incompatibility. Boards with a silver finish may require a wider aperture or thicker stencil to gain the same solder volume.

What assembly conditions can the finish withstand?

Testing has been done up to 6 cycles of 30 seconds at a maximum of 230°C.

What fluxes are compatible with the finish?

Immersion silver should be a drop-in replacement for HASL and is compatible with most fluxes. If you have questions concerning a specific flux, please contact your sales representative

What is the expected shelf life?

Hunter guarantees the immersion silver product for six months barring exposure to extremes in temperature and humidity. It is recommended the boards be kept in their original packaging until use.

How do you prevent the silver from tarnishing?

Keep finished boards in packaging until ready for use. The Sterling™ surface deposit contains organics that help inhibit tarnish, but if the boards are left exposed to atmospheric conditions, sulfides can eventually form on the PCB surface.

What is the finish thickness?

Ranges from 8-16 micro inches.

How do you assure the quality of the Sterling™ silver coating?

Solderability is tested by lot per ANSI/IPC J-STD-003. XRF readings are taken to monitor finish thickness.

Design Concerns:

Can immersion silver be combined with other board finishes?

Hunter can provide a combination finish with immersion silver and electrolytic nickel gold.