circuitnet
Sponsor
Essegi Automation
Scaling SMT Traceability
High-mix electronics manufacturing requires precise material control. This whitepaper explains how Tecnimaster improved traceability, inventory accuracy and picking efficiency through integrated automated storage and reel-level tracking.
Essegi Automation
Quick-Turn PCB Assemly
Sponsor
AIM Solder
Viscosity Does Not Equal Rheology: What Solder Paste Measurements Really Tell You
Viscosity is a useful solder paste quality control measurement, but rheology provides a more complete understanding of how paste will roll, fill, release, recover, and remain stable during stencil printing.
AIM Solder
Ask the Experts
QUESTIONS
  
SUBMIT
  
MEMBERS
  
JOIN
December 21, 2009 - Updated
December 21, 2009 - Originally Posted

Black Pad Investigation

What could be causing a black pad problem we're observing, the boards have ENIG finish? What would be a good method to detect and rework the black pads?
J. N.
Expert Panel Responses
Black Pad is typically caused by excessive Nickel corrosion when fabricating the PCB. It is something that should be resolved by your PCB fabricator during their ENIG fabrication.

Todd O'Neil
Todd O'Neil
National Sales and Marketing Manager, North America, Business Development Manager, DAGE | X-Ray component counting
Mr. O'Neil has been in the electronics manufacturing industry for over 20 years.
The black pads are due to nickel corrosion & oxidation during the gold (Au) deposition step. This is a common problem for ENIG-type board manufacturers, but it is very correctable once you determine which vendor is supplying the bad boards. Incoming board inspection should be done in order to determine which vendor is shipping you the bad boards. You can then direct the vendor to take corrective action. For boards that come in with black pads, you can reduce or potentially remove this surface corrosion by using an appropriate plasma treatment. Such plasma treatments typically utilize argon and/or hydrogen gas to sputter off the contamination (in the case of argon) and/or convert the metal oxide back into pure metal (in the case of hydrogen). Most plasma system companies like Nordson MARCH will run some samples for you in order to demonstrate how this is done. Being able to fix the black pad problem in your own facility with a plasma treatment will help you reduce scrap, and make you less dependant on the quality of the board vendors.

Scott D. Szymanski
Scott D. Szymanski
Global Marketing Manager, Nordson MARCH
Mr. Szymanski works to expand strategic alliances, strengthen partnerships with equipment suppliers, and develop future product offerings tailored to the semiconductor market. NOTE: Mr. Szymanski is no longer working at Nordson MARCH
Submit A Comment
Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name


Your Company
Your E-mail


Your Country
Your Comments



Free Newsletter Subscription
Circuitnet is built for professionals who bear the responsibility of looking ahead, imagining the future, and preparing for it.

Insert Your Email Address

Sponsor
SCHUNK
Gripping Systems from micro assembly to heavy lifting
The first industrial-suited grippers from SCHUNK were a milestone. Since then we have brought countless newly and further developments to market.
SCHUNK
Ultrasonic Stencil and Pallet Cleaner