Open The Pod Bay Doors, HASL

Does anyone use HASL (Hot Air Surface Leveling) anymore? It's also known as HAL.

Prior to the RoHS days, HASL was probably the most common surface finish. You can get it lead free, but most boards seem to use immersion silver or ENIG (Electroless Nickel Immersion Gold). HASL has traditionally come at a lower cost than those other two finishes, but immersion silver can generally be found at the same price now.

Our friends at Sunstone.com, for example, charge the same for silver and tin/lead HASL. ENIG is still more BGA on HASL closeexpensive no matter where you go though.

One of the chief disadvantages of HASL these days, is the lack of planarity on the surface. (Note the bumps on the BGA land pattern in the image on the right.) With thru-hole or large components, an uneven surface doesn't matter so much. With the increasingly smaller BGAs and QFNs, however, surface irregularities can cause big problems.

Both Immersion silver and ENIG have nice flat surfaces. OSP (Organic Surface Preservative) has a pretty flat surface too, but it's not used much except in high volume consumer goods or specialized applications.

By Duane Benson
Oh, the pain! Save me, William.

ODB++ plus, plus, plus

I wrote a bit about ODB++ back in October. Nothing has really changed much since then. I'm just clarifying a few things.

First, I want to put more emphasis on the use of ODB++. In addition to being beneficial to the manufacturing process, it can make your job a little easier. If you send us ODB++, you do not need to send either the Centroid or Gerber files. The ODB++ replaces both.

Eagle CAD does not have an ODB++ export. However, the Eagle .brd file will work too. You can send us the .brd instead of the Centroid and Gerber files.

If you can't send either of those formats, we still need the Centroid and Gerbers (top copper, bottom copper, solder paste stencil, silkscreen and solder mask layers).

Number Six
I am not a number, I am a free man!

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