The thickness alone is only part of the equation leading to embrittlement. The total volume of gold as a percentage by volume within the resultant solder joint is the critical factor. There is a lot of new work that shows anytime you increase the gold content of a solder joint by more than 1%, the chances of having gold embrittlement greatly increases. So a gold layer 2 uinches thick is not likely to greatly reduce cycles to failure. But if your pads are very small such as a .004" flip chip pad with no solder paste added (reflowing the flipchip solder only) and you put on a 5-8 uinch gold layer over nickel, then you are approaching or exceeding the 1% limit. Having to form the IMC with nickel doesn't help. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey Sent: Friday, December 29, 2006 1:33 PM To: [log in to unmask] Subject: Re: [TN] Questions on ENIG VS gold plating Two would be fine if you could control the thickness across the board. I am not aware of any either. But, electroplated gold is another story. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Lee parker Sent: Friday, December 29, 2006 1:55 PM To: [log in to unmask] Subject: Re: [TN] Questions on ENIG VS gold plating Guy If two micro inches of gold is an embrittlement threat, then ENIG must be considered equally as dangerous. I am hardly a fan of ENIG, but I am unaware of any documented ENIG embrittlement failures. Best regards Lee J. Lee Parker, Ph.D. JLP Consultants LLC 804 779 3389 ----- Original Message ----- From: "Guy Ramsey" <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, December 29, 2006 1:09 PM Subject: Re: [TN] Questions on ENIG VS gold plating > I didn't read your paper but my experience mirrors Werner's. It is > very difficult to get a thin, even, always present electroplate. A two > micro inch minimum might easily result in spots that are thick enough > to cause brittle solder connections. A two micro inch maximum might > easily fail to protect the nickel. > > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Lee parker > Sent: Friday, December 29, 2006 12:56 PM > To: [log in to unmask] > Subject: Re: [TN] Questions on ENIG VS gold plating > > Werner > > This could not be flash gold since in this process the gold thickness is > approximately 2 micro inches, which of course is where the name > originated. > The advantage over ENIG is that the porosity is greatly reduced. > > I am sure you will agree two micro inches of gold is not going to cause > embrittlement. I imagine what you have is typical plated gold with uses a > completely different and much more expensive chemistry. > > Best regards > > Lee > > J. Lee Parker, Ph.D. > JLP Consultants LLC > 804 779 3389 > > > ----- Original Message ----- > From: "Werner Engelmaier" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Friday, December 29, 2006 12:47 PM > Subject: Re: [TN] Questions on ENIG VS gold plating > > > > In a message dated 12/29/06 11:25:43, [log in to unmask] writes: > > > Many Asian shops use what they call "flash gold" > > > which is electro plated gold over nickel. > > > > > Hi Lee, > > True enough, but 2 of my clients in China had gold-embrittlement > > failures > > because some of their product had too much Au on it. > > > > Werner > > > > --------------------------------------------------- > > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > > To unsubscribe, send a message to [log in to unmask] with following text > > in > > the BODY (NOT the subject field): SIGNOFF Technet > > To temporarily halt or (re-start) delivery of Technet send e-mail to > > [log in to unmask]: SET Technet NOMAIL or 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http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > for additional information, or contact Keach Sasamori at [log in to unmask] or > 847-615-7100 ext.2815 > ----------------------------------------------------- > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > for additional information, or contact Keach Sasamori at [log in to unmask] or > 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to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE 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