TECHNET Archives

July 1997

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Condense Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Received:
by ipc.org (Smail3.1.28.1 #2) id m0wlKk3-000BjaC; Mon, 7 Jul 97 15:50 CDT
Old-Return-Path:
Date:
Mon, 7 Jul 97 11:04:00 PDT
Precedence:
list
Resent-From:
Resent-Sender:
TechNet-request [log in to unmask]
X-Status:
Status:
O
X-Mailing-List:
<[log in to unmask]> archive/latest/13815
TO:
Return-Path:
<TechNet-request>
From [log in to unmask] Mon Jul 7 17:
00:34 1997
Resent-Message-ID:
<"y_DbI3.0.HlM.iqImp"@ipc>
Subject:
From:
[log in to unmask] (James C. Patten)
X-Loop:
>From willli Mon Jul 7 15:
50:53 1997
Message-Id:
Parts/Attachments:
text/plain (79 lines)
Werner,
What is mechanism of failure for stress concentrations from soldermask-defined 
solder openings? - Thanks
James Patten
TRW
> From [log in to unmask] Mon Jul  7 05:34:49 1997
> Resent-Date: Mon, 7 Jul 1997 07:13:30 -0700
> Resent-Sender: [log in to unmask]
> Old-Return-Path: <[log in to unmask]>
> From: [log in to unmask]
> Date: Mon, 7 Jul 1997 07:41:20 -0400 (EDT)
> To: [log in to unmask]
> Subject: Re: Solder joint design rules
> Resent-Message-Id: <"dWFcY.0.qD9.jDDmp"@ipc>
> Resent-From: [log in to unmask]
> X-Mailing-List: <[log in to unmask]> archive/latest/13805
> X-Loop: [log in to unmask]
> Resent-Sender: [log in to unmask]
> Content-Length: 2554
> 
> Gidday Ingemar,
> (Gidday is likely a phonetic spelling of the Australian equivalent of Good
> Day).
> The geometry of a solder joint can be an indicator of improper wetting, which
> certainly can lead to solder joint failures, but in and of itself not very
> important for solder joint reliability with one exception--solder joint
> height. One also should avoid geometries causing stress concentrations, like
> solder-mask-defined soldering openings. 
> The reason for all this is that solder joint failures (again with the
> possible exception of improperly wetted solder joints) are not
> stress-driven--they are strain-driven. Solder joints at typical operating
> temperatures (above -23oC) creep readily and therefore do not support
> stresses for long, they give. 
> The most important design step for solder joint reliability is the reduction
> in the magnitude of the thermal expansion mismatch. I would recommend using
> the industry document IPC-D-279, 'Design Guidelines for Reliable Surface
> Mount Technology Printed Board Assemblies'. 
> While the choice of the solder alloy can make some difference in the
> reliability of solder joints, this difference is small in comparison to other
> more significant factors, i.e. solder joint height, component size, delta-T,
> delta-CTE, lead compliance. 
> You may be interested in a workshop on solder joint reliability I will be
> giving at ISHM-Nordic on September 21, 1997 near Oslo. You could get more
> information from Katarina Boustedt, Ericsson Microwave Systems, Core Unite
> Research Center
> Microwave and High Speed Electronics, SE-431 84 Molndal, Sweden, ph: +46 31
> 747 0219, fax: +46 31 747 0317, email: [log in to unmask]
> 
> Werner Engelmaier
> Engelmaier Associates, Inc.
> Electronic Packaging, Interconnection and Reliability Consulting
> 23 Gunther Street
> Mendham, NJ  07945  USA
> Phone & Fax: 973-543-2747
> E-mail: [log in to unmask]
> 
> ***************************************************************************
> * TechNet mail list is provided as a service by IPC using SmartList v3.05 *
> ***************************************************************************
> * To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
> * with <subject: subscribe/unsubscribe> and no text in the body.          *
> ***************************************************************************
> * If you are having a problem with the IPC TechNet forum please contact   *
> * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
> ***************************************************************************
> 
> 

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************


ATOM RSS1 RSS2