Richard, Maybe Joyce is saying that each customer specifies their own unique requirements in the absence of a superlative generic standard. I prefer to use the Weibull approach as opposed to the average & std deviation approach. Steve C -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: Wednesday, January 06, 2010 11:25 AM To: [log in to unmask] Subject: Re: [TN] Pull strength of thermosonic wire bondable gold So, when these venerable suppliers fall outside of the range of their process capabilities, what benchmarks are used to determine what went wrong, if no standards are required? -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo Sent: Wednesday, January 06, 2010 9:16 AM To: [log in to unmask] Subject: Re: [TN] Pull strength of thermosonic wire bondable gold You learn to trust your supply. It is such a specialized area you do not want to risk lost your reputation. The vendor has more skin in the game than you can imaging. That is how they are the few still standing. The problem for most of the assemly house in US, you do not have large enough volume even get their attention. Check taiwan and singapore contract mfg house, see who is their supply will tell you the story. Too bad, US has fall off the radar screen on the wire bondable gold supply for now. -------------------------- Sent using BlackBerry ----- Original Message ----- From: TechNet <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Sent: Wed Jan 06 09:59:30 2010 Subject: Re: [TN] Pull strength of thermosonic wire bondable gold Joyce, And if they do a Weibull plot on their data, you can see changes in the characteristic strength, etc. from lot to lot and use that as a accept/reject gauge before it even leaves their house. The platers/shops I like to work with have bonders. However, sometimes you have to train them how to use them.... :-( Anyone can smash the bejeebers out of a 'bond' and call it 'good'. That is not the way I prefer to play the game! I can also play with looping to fudge the numbers too. Have to keep your eyes open - 'trust' but verify! Been there done that! Regarding thin Nickel [<50 µinch] there is one situation where you can usually get away with it - Aluminum wire with absolutely no prior thermal excursions to the part. If you subject the part to a reflow operation and it has thin and/or porous nickel, you will experience increased bonding difficulties as compared to a virgin board without the thermal excursion. Shows up on Weibull plots too! As time after thermal exposure increases, even more of the diffused copper will oxidize, further increasing bonding problems. I don't believe the rate of Cu diffusion thought the Ni is all that great at room temp. It is my opinion based on bonding parts over the years that you need that thermal kick to get it moving. Once the copper gets up into the gold, bondability goes down the toilet very quickly! You can even see the color change by eye in many cases. Maybe Dave H has an equation for the diffusion rate, or desires to chime in. Steve C -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo Sent: Wednesday, January 06, 2010 9:43 AM To: [log in to unmask] Subject: Re: [TN] Pull strength of thermosonic wire bondable gold It all boil down to volume vs price. If you have volume and price advantage, you will find the top supply house (at least one or two, if not three). No standard required. It is such a highly specialized area that in house spec is good enough. The guys make the high end large volume even has wire bonder in QA with the bond pull force listed for every batch (if you pay top dollar). -------------------------- Sent using BlackBerry ----- Original Message ----- From: TechNet <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Sent: Wed Jan 06 09:17:55 2010 Subject: Re: [TN] Pull strength of thermosonic wire bondable gold This begs the question, are there IPC or other standards for die and wire bonding that define what the specific alloys and nickel thickness and the gold thickness ranges shall be, similar to those within IPC 4552 and 4553? Looking back at these issues in doing a search of the forum archives, it appears that this is an issue that many people keep struggling with. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask] Sent: Wednesday, January 06, 2010 8:14 AM To: [log in to unmask] Subject: Re: [TN] Pull strength of thermosonic wire bondable gold Hi Steve, Nickel below 80-90 microinches will not act as a barrier due to porosity. You may get copper migration at 40 microinches of Ni which will effect bonding. Regards Aleks Lozinsky Technical Sales Representative Technic Canada Inc. Office: 905-940-4020 Cell: 416-450-1093 E-mail: [log in to unmask] -----Original Message----- From: Steve Kelly <[log in to unmask]> Date: Wed, 6 Jan 2010 08:50:49 To: <[log in to unmask]> Subject: Re: [TN] Pull strength of thermosonic wire bondable gold Hi Steve et al, Unfortunately this is not as easy as it sounds. First the lower pull strengths are not necessarily a failure- they are just not as good. This was an experiment designed between ourselves and our customer. The initial problem is we have a .0032 wide flying lead ( about 150 of them) with no kapton support. A chip/die is "compression bonded" onto the lead - from what I can gather it is a combination of heat/pressure/ultrasonic and some kind of proprietary magic. The reason we went to the lower nickel is because the leads being so fragile they often crack during the process so we tried the lower nickel to alleviate this issue. With the lower nickel pull is approx. 5-7 grams. With the higher nickel 9-11 grams. There is a gold bump on the die and when the failure happens the gold bump separates from the lead with no damage to the gold bump. At present this is as much as I know. Thanks for the input so far. Steve Kelly -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick Sent: January-05-10 6:14 PM To: [log in to unmask] Subject: Re: [TN] Pull strength of thermosonic wire bondable gold Steve, If you can send me the data sets in an Excel format, I can provide you with some insight based on magnitude and grouping by Weibull plot. If there is a big mix of failure modes, this interpretation will be pretty generic. Its free input, however :-) Just send it direct. Steve C -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Kelly Sent: Tuesday, January 05, 2010 4:17 PM To: [log in to unmask] Subject: [TN] Pull strength of thermosonic wire bondable gold Hi All, I have a wire bond question to the wire bond gurus who have helped me out a lot in the past. Made 2 versions of a flex circuit - only varied the nickel thickness. Application is thermosonic gold wire bonding. Flex circuit lead is .0032 wide - version 1 - nickel is 150 microinches - soft gold is 50 microinches- pull strength is X Version 2 - nickel is 40 microinches - soft gold is 50 microinches - pull strength is approx. ˝X of version 1- Is this what I should expect? Regards Steve Kelly Steve Kelly (PLEASE NOTE NEW E-MAIL ADDRESS) (416) 750-8433 (work) (416) 750-0016 (fax) (416) 577-8433 (cell) --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. 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