Hi All,
Most of TGAsia members here are likely to know what the TG is.
I am sharing with you this TG spreadsheet which shows all technical committees, some of sub-committees and TGs in US.
This spreadsheet is being updating by John who is working from IPC HQ in US. What it looks now is the achievements on yeaterday. I would send it again after finishing of it.
Upon this talking about BGA and voids, I suppose that it's the time for us to set up another TG CN of 5-21fCN soon.
The good thing is we have had 7095A translated. Anyone likes to volunteer?
Thanks and Regards
Leesha Peng 彭丽霞
标准开发/设计课程与技术资源项目总监
Director, Standards/Design Programs
& Technical Resources
上海市延安西路1088号2303室
邮编：200052
手机:13902994705
________________________________
From: TGAsia 代表 John Perry
Sent: 2007-4-12 (星期四) 15:24
To: [log in to unmask]
Subject: Re: [TGA] 答复:Re: [TGA] BGA voids
Hello All,
Peter made a good point in the reference of IPC-7095A for BGA design and assembly process implementation. I should point out that, as indicated in section 7.5 of that document, the detailed requirements for end product acceptance of BGA solder voids shall be in accordance with J-STD-001, and that section 7.5 of IPC-7095A establishes the practicable process development and maintenance criteria as well as attempting to address the issues related to an acceptable assembly process for BGA solder voids.
There is a Revision B to IPC-7095 that will soon be available for final draft review. Section 7.5 of the IPC-7095B is being expanded to include detailed tables providing corrective action indicators for BGA voids based on the pitch of the BGA land pattern.
Regards,
John Perry
Technical Project Manager
IPC
3000 Lakeside Drive # 309S
Bannockburn, IL 60015
[log in to unmask]
1-847-597-2818 (P)
1-847-615-7105 (F)
1-847-615-7100 (Main)
________________________________
From: TGAsia [mailto:[log in to unmask]] On Behalf Of Deng, Peter (Shenzhen)
Sent: Thursday, April 12, 2007 2:43 PM
To: [log in to unmask]
Subject: Re: [TGA] 答复:Re: [TGA] BGA voids
IPC-7095, design and assembly process implementation for BGAs is more compatible than IPC-A-610 for voids in BGA solder.
Of course, we should obey of client’s requirement at first level.
It is personal opinion and only for your reference.
Kind Regards
Peter Deng
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________________________________
From: TGAsia [mailto:[log in to unmask]] On Behalf Of Chris Katzko
Sent: Thursday, April 12, 2007 5:22 PM
To: [log in to unmask]
Subject: [TGA] 答复:Re: [TGA] BGA voids
My advice would be:
1. Consider the application, is it fixed equipment (desktop PC, etc) or handheld/mobile product (mobile phone, notebook PC, automotive product) subject to shock and vibration? If there is a potential for drop-shock or vibration, you should be careful to verify by testing since gas voids make the ball mechanically weaker.
2. What is the device ball pitch? CSP devices 0.65mm pitch or smaller have very small, fragile balls. Again, treat with care.
3. What is the PCB surface finish and solder metallurgy? OSP or I-Ag combined with eutectic (Sn63Pb) are quite robust, ENIG and I-Sn a little less so. OSP and I-Ag with SAG 3xx (Lead-free) are generally robust for BGA and CSP, ENIG or some I-Sn with SAG 3xx are more sensitive to voiding and CSP devices very sensitive to IMC fractures in face-down drop shocks (this is well documentred). For CSP with non-Cu PCB metallurgy, I would really caution you to avoid risk without testing.
4. Generally the risk increases with Lead-free solders since the metallurgy is more complex and tertiary alloy formation more likely, resulting in higher risk for creep stress fracture and drop shock fracture formation.
I suggest you put the question to your silder vendor as well, they may be able to provide soime reference test data for the solder youvare using.
I agree with Andy, IPC 610 is not absolute and you need to consider your customers specifications and applications. When in doubt, TEST.
C.B. Katzko, CTO
Meadville Group
e-mail [log in to unmask]
tel +86 21 5774 6907
fax +86 21 5774 0635
mobile +86 13817362590
-----TGAsia <[log in to unmask]> 撰写：-----
收件人: [log in to unmask]
发件人： "Duan, Shi Hao - Andy BSCE QA PEK" <[log in to unmask]>
发件人: TGAsia <[log in to unmask]>
日期: 04/12/2007 09:03上午
主题: Re: [TGA] BGA voids
Actually you can not rely on 610 only. I think sometimes voids can be benefit for vibration. So best way for you is to find your customer requirement. If no requirement in your contract for void rate, i think if you can prove that your products are OK, you can deliver it at once. But don't forget to get the proof first.
Best regards,
Duan Shi Hao (Andy)
------------------------------------------------------------------------
Quality Department
Beijing Siemens Cerberus Electronics Limited
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________________________________
From: TGAsia [mailto:[log in to unmask]] On Behalf Of George Liu (DMN)
Sent: Thursday, April 12, 2007 8:57 AM
To: [log in to unmask]
Subject: [TGA] BGA voids
Dear all,
Need your advice /comment:
F or BGA void, IPC- A- 610 acceptance criteria is < = 25% area by X-ray image. W hat if the void >25% area by cross-section though it is acceptable by x-ray image? Is it still acceptable or we should reject it ?
IPC criteria:
Table 8-12 Dimensional Criteria - Surface Mount Area Array Features
Feature Classes 1,2,3
Voids 25% or less voiding in a ball x-ray image area.
Thanks & best regards
George
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