Hi, Wee Mei,
Yes, you are correct - unless you pre-heat the entire board above 125 deg C
before hand soldering. If you're hand soldering a "cold" board, there is no
issue with pop-corning.
Peter
Lum Wee Mei <[log in to unmask]> 25/01/2003 09:26 AM
Sent by: TechNet <[log in to unmask]>
Please respond to "TechNet E-Mail Forum."; Please respond to Lum Wee Mei
To: [log in to unmask]
cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group)
Subject: Re: [TN] Moisture sensitive
Hello,
Since we are in this MSD discussion, I would like to share with all what
my colleague shared with me a page from the book : Plastic Encapsulated
Microelectronics - Materials, Processes, Quality, Reliability and
Applications by Michael G. Pecht, Luu T. Nguyen an dEdward B Hakim that
states :
...High temperature and temperature ramp rates, prime loads that cause
popcorning are experienced by the packages during surface mounting on
circuit boards. Of particular concern are solder reflow processes that
heat the package body such as infrared heating, hot-air furnace and
vapor phase reflow. . . . . Wave soldering may be a concern if
components dip through the solder wave. . . Though-hole mounted plastic
encapsulated microcircuits do not exhibit popcorning because the
component body is protected from the solder heat by the board. . .
So, am I correct to interpret that popcorning will not occur when SMDs
or PTHs components are assembled using hand soldering?
Regards
Wee Mei
Bev Christian wrote:
> Paul,Absolutely. At a previous job, I saw a TSOP that was so pregnant
> that is was drawbridged!Bev ChristianResearch in Motion
>
> -----Original Message-----
> From: Stolar, Paul W [mailto:[log in to unmask]]
> Sent: January 22, 2003 11:50 AM
> To: [log in to unmask]
> Subject: [TN] Moisture sensitive
>
> Has anyone ever seen moisture damage in plastic IC's which
> are not BGA's?
>
> Paul Stolar
>
> Materials Engineer
>
> Baker Atlas
>
> 713-625-5376
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