Gerard O'Brien President S T and S Testing and Analysis Gerald O'Brien is Chairman of ANSI J-STD 003, and Co Chairman of IPC 4-14 Surface Finish Plating Committee. He is a key member of ANSI J-STD 002 and 311 G Committees Expert in Surface finish, Solderability issues and Failure analysis in the PWA, PWB and component fields.
Gerard O'Brien has submitted responses to the following questions.
How to Re-qualify BGA Spheres I take it you mean for solderability. This can be done either with a wetting balance and using a low ...
Cleaning Under Low Clearance Components
Your concerns are valid however the ability to clean will depend on the surface tension of the water solution you ...
Old Components and Blow Holes Blow holes are primarily the result of poor hole wall generation of the PWB and defective or insufficient plating thickness. ...
Is Solder Mask Considered an Insulator Solder mask was designed to prevent solder bridging period. Its ability to act as an insulator is an added benefit ...
Out-gassing and Cleaning Due to the nature of the materials you are using, there will be outgassing under vacuum, although you did not ...
Solder Splashes During Wave Soldering Have you confirmed the preheat profile is meeting the flux suppliers recommendations? If using a VOC free flux, it is ...
Soldering Components with Silver Pads Ag dissolves at the rate of approx. 50 microinches /sec at soldering temperatures. What thickness of Ag is present on ...
Bottom Terminated Components and Vias
Unless
you are using a dry film solder mask, you are kidding yourself with tenting to
prevent flux and other ...
Gold Plating and Embrittlement
Gold
embrittlement occurs at 5 wt.% in the solder joint although the industry
usually defaults to 3 wt.%. You can ...
Via Wall Thickness Test There are a number of copper plating thickness
"meters" where by you insert a probe into a plated through hole ...
A Generic Reflow Profile The only way that a single profile could be used
for all board designs would be if the rate of ...
What Causes Black Pad? Black
pad occurs during the immersion gold deposit and not during assembly which is
responsible only for revealing the defect. ...
Deionized Water Sample Testing Exposure to atmosphere will definitely impact the resistance of the
water as will the container you are using -- but ...
BGA Die and Pry Testing The amount of dye penetration looks too extensive for Kirkendall voids.
Are the images showing ball separation from the chip? ...
Mixing Different SAC305 Solders Provided
the new material meets the requirements of the appropriate JSTD, I would see no
issues in mixing the SAME ...
Gold Plated Hole Defects The
first question is how many layers of interconnect are there in these holes
typically? When you say exposed gold, ...
HASL vs. Immersion Gold If
you are leaving exposed pads or test points that will be susceptible to
atmospheric attack then there have been ...
