Plating of semiconductor leadframes
Q. I am currently a student on attachment in an electronics company. My job is to solder-plate the leadframes as well as to optimise the parameters in a strip to strip plating machine. I would like to know more about the history, present status and its likely future direction of the plating of semiconductor leadframes. Also, please advise me on the pros and cons of using barrel, rack and strip (reel-to-reel) plating.
Anyone with the required knowledge, please help me. I would appreciate it very much. Thanks!Dennis L [last name deleted for privacy by Editor]
A. Hopefully, it is you that will show us the future. Immerse yourself in the plating solution (not literally), and let your background in pure science have free reign. Sometimes the history only gets in the way.
A. Hey Dennis, you just asked us here to type about 10,000 pages of text which you already have access to, plus about 10,000 more of our unpublished experience! My only advice is to study Chemistry, Electrochemistry, Kinetics, Transport Phenomena, Fluid Mechanics, Reactor design, Machine design, Statistics, Boundary Value Problems, Materials Science, Metallurgical Thermo, Corrosion Science, Organometallics, and never stop. Be in a hurry to understand the art, but don't be impatient with the "experts" running the place, as their decisions will undoubtably defy logic. Most importantly, identify every phenomena occurring within the machine, then pick out the math model that describes it from one of your textbooks and set it up and solve it. Then keep modifying it as your experiments indicate. But don't let your "higher-ups" know that you are actually using your texts to understand the process, or they will surely conclude that you are wasting your time.
Q. I'm also currently working in IC industry. I'm having a trouble with the plating process. The frames got melted in ED process. Has anyone ever faced this problem? Please advise me for the root cause and countermeasure.
- Chiang Mai, Thailand
December , 2012
A. Hi Monchida. "Melting" can surely be indicative of only one thing: a short circuit. The strip has a substantial voltage (perhaps 4 to 12 volts) applied to it and its resistance is negligible. If this negatively charged strip touches something that is grounded or connected to the negative lead, it will quickly fry. Good luck.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
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