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COB Issue's (Non-Sticking)


COB Issue's (Non-Sticking) | 18 May, 2005

Hello All,

I recently accepted a position in a manufacturer in Mauritius and they have begun a little more then a year ago COB process which I am unfamiliar with and needing some help. We are using aluminum wire, the machine is Dias Automation model number US-2900-B. I have read the forums on COB topics and have started investigating the quality of the boards as far as ENIG or Electroplated and thickness of nickel and gold as well as purity of the metals. I have not received responses back yet from the board manufacturer's. I am questioning if our process is good since it seems the people who were trained in setting up the process have all resigned. I am hoping to get insight for why we have non-sticking problems. Please help me by first explaining to me how the process should be done correctly. I would appreciate any insight on this matter, thank you.

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COB Issue's (Non-Sticking) | 18 May, 2005

Wire bonds don't stick when bonded * Check pull and shear strength. * Depending on point of failure, review parameters. * Listen during bonding, if there is a high pitch buzz, there is vibration in the system somewhere, "seek and destroy". * Get the plating analyzed, and look for high surface contaminants.

"Wire Bonding in Microelectronics" GG Harman, (New York: McGraw-Hill, 1997) is an excellent book used to aid an experienced wire bonder in troubleshooting process, but alas does little for the beginner. "Wire Bond" (College Station, TX: Texas Engineering Extension Service, 2001) is a very good introduction to wire bonding.

Does your wire bond machine supplier offer training courses?

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COB Issue's (Non-Sticking) | 18 May, 2005

Yes we have purchased a second machine due to low through put so he will be here on the 6th of June....I will be involved with training then, but so far I have not seen great support from this company as far as thier own knowledge of some problems that can be incured in this process. I will purchase both of those books, I was just hoping to obtain a quick summary of how the process is supposed to be run to get good yields so I could attempt to trouble shoot just how they are doing things now, which I am not sure is being done correctly. I appreciate your response and I will continue to research the issue's.

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