Reuven - I disagree with your assertion that VIP is not 100% safe.  With
proper selection of via fill material and a reasonable hole aspect ratio,
you should have neither solderability or void issues.
Mike McMaster
RF Product Engineer
Merix Corporation
503-992-4263



> ----------
> From:         Reuven ROKAH[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;[log in to unmask]
> Sent:         Monday, June 28, 2004 10:08 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] VIA in Pad
>
> I recommend to try as a first priority to layout the via out of the BGA
> pad
> (bump) to adjacent special micro via hole pad.
> Up to 0.5 mils pitch it can be done.
> The filling VIP is not 100% safe (solderability and voids aspects).
>
>
> Best  Regards
>
> Reuven  ROKAH
>
>
>
>
>                       "Macko, Joe @
>                       IEC" <joe.macko          To:      [log in to unmask]
>                       Sent by: TechNet         cc:
>                       <[log in to unmask]         Subject: Re: [TN] VIA in
> Pad
>                       >
>
>
>                       28/06/2004 17:35
>                       Please respond
>                       to "TechNet
>                       E-Mail Forum.";
>                       Please respond
>                       to "Macko, Joe @
>                       IEC"
>
>
>
>
>
> Tom,
>
> My experience has been that their generally a direct correlation between
> voiding and VIP locations.  Of course, the size of VIP has a direct
> bearing
> on the potential size of the void in the solder ball .....  Our current
> policy is to fill all VIPs to preclude any voiding problems or
> insufficient
> solder conditions in leaded parts.
>
> I would sensitize your customer to the potential for voiding which may not
> meet IPC guidelines, and the need for rework with VIPs for leaded parts.
> Good luck.
>
> joe
>
> -----Original Message-----
> From: Tom Parkinson [mailto:[log in to unmask]]
> Sent: Friday, June 25, 2004 8:20 AM
> To: [log in to unmask]
> Subject: [TN] VIA in Pad
>
>
> We're a CM.  One of our customers is asking us to build a board assembly
> that will be using BGAs with VIAs in pads.  They are in the design stages
> at
> this point, and we have some concerns with having a Via in the middle of a
> BGA pad.  Anyone have suggestions and/or experience with this??
>
>
>
> Thanks
>
>
>
>
>
> Tom Parkinson - Quality System Manager - CIT
>
> WinTronics, Inc.
>
> Ph: 724-981-5770 Ext. 235
>
> Fax: 724-981-1772
>
>
>
>
>
>
> ---------------------------------------------------
> 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
> 847-509-9700 ext.5315
> -----------------------------------------------------
>
> ---------------------------------------------------
> 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
> 847-509-9700 ext.5315
> -----------------------------------------------------
>
> ---------------------------------------------------
> 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
> 847-509-9700 ext.5315
> -----------------------------------------------------
>

---------------------------------------------------
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 847-509-9700 ext.5315
-----------------------------------------------------