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In one of my PCB design, the microprocessor soldering leg pad size are .254mm x 1.4mm while the ground(GND) routing trace is .4mm thick. I'm trying to figure out is it safe to route the .4mm thick trace to the .254mm soldering leg pad of the microprocessor? enter image description here

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  • \$\begingroup\$ What soldering method are you using? \$\endgroup\$ – winny May 17 at 20:08
  • \$\begingroup\$ I'm hand soldering. \$\endgroup\$ – Mike May 18 at 13:22
  • \$\begingroup\$ Then you are only limited by the power your soldering iron can provide. I doubt it’s enough to cause a problem. \$\endgroup\$ – winny May 18 at 14:04
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You should be OK with the large copper area under the pad. However, you should use solder resist to define the pad area (the purple lines on pads 3 and 5) if soldering with solder paste, to stop the solder running away from the joint. This is less important if you are hand soldering, as you can just add more solder during soldering.

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Use a thin thermally isolated short connection to the pad for best soldering flow practices.

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  • \$\begingroup\$ Are you hand-soldering, or reflowing? I do mostly skillet reflow in my home shop, and as long as I do a long enough preheat I get good consistent results soldering onto all different sizes of heat spreaders. \$\endgroup\$ – TimWescott May 17 at 21:05
  • \$\begingroup\$ That advice was based on my reflow experience for DIY and large scale. I was Ops Mgr for a microwave R&D where we churned out prototype designs in a day with two stockrooms of trays and reels, etch and 603 reflow and larger. Film was photographic and UV resist used. Parts were hand placed soldered , shields were etched locally from brass then Zn plated folded, soldered over ceramic hybrids. Then at C-MAC as Eng. Mgr we had 3 reflow and 2 wave lines for doubled sided. \$\endgroup\$ – Tony Stewart EE75 May 17 at 22:10

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