John,
Design For Manufacturability is the name of the game: good design of the pads, and moreover - thermal balance between the lands and the patterns. Also, the traces from both lands should be equal in width and be connected to the lands along the component long axis.

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


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of John Foster
Sent: Monday, January 26, 2004 20:00
To: [log in to unmask]
Subject: [TN] 0402 SOLDERING


I know that 0402 is a mature technology. I am getting ready to do a board
which will use all 0402 passives. I have very little experience with 0402.
From what I have been reading it seems very important that components go
through the oven broadside so that both sides go liquidous at the same time.
I also have read that it is important to keep the copper or thermal
structures as close as possible on both sides.

What I was hoping to ask is from the experience of people is this really the
case anymore. It is very difficult to lay out a board with all of the
passives facing the same direction. The copper or thermal on both sides is
very much less difficult.

Any input on this subject would really be appreciated.

Thank You
John Foster

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