Doug

I've never seen any pics with parylene coating, have you? I  know I coat
plenty of BGAs with XY. Just curious how well it penetrates.


Lloyd Duso
Diamond-MT
Plant Manager
(814) 535-3505
www.Diamond-mt.com


On Fri, Sep 13, 2013 at 10:59 AM, Douglas Pauls <[log in to unmask]
> wrote:

> Yup.  That is the picture I show when the design engineer is convinced you
> have to coat every ball on a BGA for waterproofness.
>
> Doug Pauls
>
>
>
> From:   Steve Gregory <[log in to unmask]>
> To:     <[log in to unmask]>
> Date:   09/13/2013 09:14 AM
> Subject:        Re: [TN] Gull wing solder joints and minimum electrical
> clearance
> Sent by:        TechNet <[log in to unmask]>
>
>
>
> Hi Dave!
>
> Hi to you too Doug, got your picture. WOW. I had no idea that happens!
>
> http://stevezeva.homestead.com/SquishedBalls.jpg
>
> So when you coat a board that has BGA's, I take it that just a layer of
> coating won't cause this, but if the coating wicks beneath the BGA you
> can have problems?
>
> Steve
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
> Sent: Friday, September 13, 2013 6:17 AM
> To: [log in to unmask]
> Subject: Re: [TN] Gull wing solder joints and minimum electrical
> clearance
>
> Hi Victor - I don't have an example of what happens to a QFP as Ian
> detailed but  Doug and I have the same phenomenon for a BGA.   Hey Doug
> -
> can ya send Steve one of the BGA pictures?
>
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
>
>
> From:   Victor Hernandez <[log in to unmask]>
> To:     <[log in to unmask]>
> Date:   09/13/2013 05:50 AM
> Subject:        Re: [TN] Gull wing solder joints and minimum electrical
> clearance
> Sent by:        TechNet <[log in to unmask]>
>
>
>
> Can you share this phenomenon photo?
> Victor,
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Fox, Ian
> Sent: Friday, September 13, 2013 2:39 AM
> To: [log in to unmask]
> Subject: Re: [TN] Gull wing solder joints and minimum electrical
> clearance
>
> Here's a phenomenon that can occur Richard. On fine pitch QFPs with a
> generous volume of solder in the joint or a bulging joint, the presence
> of a reasonable thickness of acrylic conformal coating (say 100um)
> between the feet of the device, together with regular extended periods
> of time below zero degC (say -10 degC) can result in the solder being
> extruded out of the joint thus forming a short to the adjacent lead. The
> modulus of the acrylic is greater than that of the SnPb at sub zero
> temps so the solder is under compression and flows.
>
> Been there and got that particular T-shirt
>
> Regards
> Ian
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
> Sent: 11 September 2013 20:03
> To: [log in to unmask]
> Subject: Re: [TN] Gull wing solder joints and minimum electrical
> clearance
>
> Joyce, how would it affect reliability?
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
> Sent: Wednesday, September 11, 2013 1:18 PM
> To: [log in to unmask]
> Subject: Re: [TN] Gull wing solder joints and minimum electrical
> clearance
>
> More likely effect your reliability than electrical clearance.
>
> Joyce Koo
> Researcher
> Materials Interconnect Lab
> Office: (519) 888-7465 79945
> BlackBerry: (226) 220-4760
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Peter Wong
> Sent: Wednesday, September 11, 2013 2:06 PM
> To: [log in to unmask]
> Subject: [TN] Gull wing solder joints and minimum electrical clearance
>
> We have assemblies where gull wing solder joints have so much solder
> that along the side joint, the solder connection extends out to the
> adjacent leads similar to Figure 5-1, Image C from IPC-A-610E.  "the
> solder connection to a termination may exhibit a wetting angle exceeding
> 90 degrees when it is created by the solder contour extending over the
> edge of the solderable termination area or solder resist" (We will be
> modifying our stencils to reduce the amount printed on these parts in
> the future).
>
> There is no IPC-610 spec for this condition so we were thinking that if
> the spacing between the solder joints does not violate Minimum
> Electrical Clearance, they are acceptable.
>
> Is this a correct acceptability criteria?
>
> Thanks,
> Peter
>
> ________________________________
> The enclosed documents are proprietary items to Silicon Forest
> Electronics' (SFE) customers. They shall not be reproduced nor disclosed
> for any purpose except as specified in writing from an authorized agent
> of SFE. These documents may contain data restricted for export by the
> International Traffic in Arms Regulations (ITAR) section of the Arms
> Export Control Act (or the Export Administration Act). Violators are
> subject to severe criminal penalties.
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud
> service.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
> ---------------------------------------------------------------------
> 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. Any use of this information by anyone other than
> the intended recipient is prohibited. If you have received this
> transmission in error, please immediately reply to the sender and delete
> this information from your system. Use, dissemination, distribution, or
> reproduction of this transmission by unintended recipients is not
> authorized and may be unlawful.
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud
> service.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud
> service.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
> ______________________________________________________________________
> This email has been scanned.
>
> ______________________________________________________________________
> Aero Engine Controls is part of the Rolls-Royce Group, whose legal
> entity is Rolls-Royce Engine Control Systems Limited which is registered
> in England.
>
> Registered office at Moor Lane, PO Box 31, Derby, DE24 8BJ. Company
> number 6686268, UK VAT number GB 939 396 075
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud
> service.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud
> service.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
>
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud
> service.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>
>
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________