Phil,
The resistor termination is pure Sn, and it is soldered using
Sn62Pb38Ag2. I sent some resistors on a blank PCB to the reflow oven. I
placed paste on some of the terminations. The bubbles appeared on those
termination where paste was present.
 
Regards
Ofer Cohen
Manager
Quality Assurance, Reliability and Production Technologies
Seabridge Ltd. - A Siemens Company
Siemens COM FN A SB 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phillip Bavaro
Sent: Monday, September 12, 2005 19:44
To: [log in to unmask]
Subject: Re: [TN] Resistor Acne

Hi Ofer,

What is the metalization of the resistor termination and what alloy
solderpaste are you using with it?  Have you watched it under a rework
reflow to see if it bubbles?  A microsection would be helpful to know
what is going on beneath the surface.

Phil

Ofer Cohen <[log in to unmask]> wrote:
Hello, all,
An inspector found something that Steve Gregory named as "resistor acne"
(all rights reserved to Steve). We were not able to figure out the
possible causes and effect on the product reliability. Steve placed the
picture on his site. Please go to http://www.stevezeva.homestead.com
click on "Picture Page 2", then Look for "Resistor Acne"... Any idea
will be welcomed.

Regards
Ofer Cohen
Manager
Quality Assurance, Reliability and Production Technologies
Seabridge Ltd. - A Siemens Company
Siemens COM FN A SB

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