Skip to main content


PCB Manufacturing
PCB Assembly
PCB Design and Layout
PCB Basics
Vias, Drilling & Throughplating
PCB Fabrication
PCB Ordering

Due to the widespread focus on RoHS regulations, lead-free surface finishes are gaining a lot of popularity. One such Pb-free finish is immersion silver, which can be applied directly on copper surfaces and is ideal for EMI shielding, aluminum wire bonding, etc.


Immersion silver is an environment-friendly surface finish plated on the copper surface of a PCB to assure good soldering of components. It is the process of depositing a thin layer (5-15 µin) of silver by a chemical reaction between silver ions and the metal copper present on the board. Currently, this surface finish is the best choice due to its outstanding performance and affordable cost. When compared to OSP and immersion gold, silver finish process is a lot simpler and quicker. It can maintain its electrical properties and solderability even after exposure to heat, pollution, humidity, etc. However, it will tarnish because of the absence of nickel underneath the silver. This finish lacks physical strength like immersion gold.

Immersion silver finish on a PCB


Immersion silver follows a particular sequence of steps with specific temperature, duration, and operating mode. Some of the stages are pre-treatment, acid degreasing, micro etching, etc. Among these the two crucial ones are:

  • Pre-treatment – involves pickling, scrubbing, washing, and drying.
  • Post-treatment – consists of washing and drying.

The displacement reaction of silver finish is:
2Ag+ + Cu = 2Ag + Cu++

Once the copper surface is micro-roughened with the micro etching solution, immersion silver layer is gradually plated at a controlled silver deposition rate. Immersion at a slower speed allows a dense crystal to form, resulting in a high-density layer of silver, as well as avoiding particle growth due to precipitation and agglomeration. Immersion silver solutions are stable, have a long service life, and are unaffected by light and traces of halides.


The advantages include:

  • Budget-friendly (less expensive than immersion gold)
  • Flat surface and low contact resistance
  • Good for BGA and other small components
  • Strong solder connection
  • RoHS compliant

The disadvantages are:

  • Sensitive to handling
  • When left unprotected from environmental influences, silver reacts with sulfur and forms silver sulfide on the pad.


  • It is easier to use than OSP.
  • In contrast to HASL, it offers a more planar surface.
  • For storage and handling, this surface finish needs more care than immersion tin.
  • It is safer for the environment than immersion tin.
  • In dry storage, this finish will last 6 to 12 months, the same as HASL boards.
  • Boards with this finish must then be soldered within 24 hours once removed from storage.
  • If boards with silver finish have been stored for more than 12 months, a solderability test has to be performed before assembling them.

During the immersion silver plating, some common problems may occur such as galvanic effect, solderability issue, etc. These can be rectified with proper measures. It is vital to focus on materials, handling conditions, and packaging requirements for this finish.


Sierra Circuits is
headquartered in Silicon Valley.
We welcome visitors at
our 70,000 sqft facility,
located at 1108 West Evelyn Avenue
in Sunnyvale, California.
Book a tour with an account manager today!
Let us introduce you to one of the most innovative communities of engineers and designers in the world.
We can help you plan your project from design to assembled board.


Our 70,000 sqft state-of-the-art campus in the heart of Silicon Valley contains the most advanced equipment required for the manufacture and assembly of your PCBs. Whether you’re looking for standard quick turn PCBs or boards with the tightest tolerances, made from exotic metals, there’s a reason Sierra Circuits leads the industry in quality and performance.

PCBs manufactured and assembled in the United States


Sierra Circuits can manufacture your PCB and have it expedited to you within 24 hours.

Full turnkey boards, with assembly and components in as fast as 5 days.

Get an Instant, Itemized Quote


24 hours a day, 7 days a week.

Call us: +1 (800) 763-7503
Email us: through our Customer Care form

SG飞艇在线计划 澳洲幸运5在线投注 澳洲8在线投注 SG飞艇计划全天 SG赛车开奖规律 澳洲幸运10开奖号码 极速飞艇开奖预测