All,
Regarding inspection and acceptable criteria for a Power Switch IC with a heat slug underneath. Per attached pictures (Thanks Steve Gregory!), we will get solder conditions as shown where we are not obtaining a visual 100% wetting on the side overhangs "ears". We know we have solder under the part by verifying with removal of the part.
1 - We are not inspecting these with our AOI's due to the inconsistent solder joint and wetting on the outside "ears"
2 - One of the pictures shows our stencil aperture design for this part and it shows we are applying paste to the entire area of this power plane.
3 - Per IPC 8.3.14 (Components with Bottom Thermal Plane Terminations), we must achieve 100% wetting to land in the contact area, or it is considered a defect all three classes.
4 - The solder applied to the "ears" wicks underneath the part leaving little solder left for the "ears".
5 - See attached photo showing board layout and pad design. We unfortunately do not have the option of redesigning this pad.
What criteria do we inspect by? Is this acceptable? I don't know how I can control the solder so it will not wick to the underside of the part and allow visual evidence on the outside "ears" of the part.
We would be required to 100% inspect each board and apply solder to the ears to achieve passing criteria?
Hopefully some of you have seen this type of situation and have experience on how to inspect and what is the criteria for inspection?
Thanks for your time!
Jim
http://stevezeva.homestead.com/IMG2.jpghttp://stevezeva.homestead.com/IMG3.jpghttp://stevezeva.homestead.com/IMG4.jpghttp://stevezeva.homestead.com/IMG6.jpghttp://stevezeva.homestead.com/Power_IC.jpg
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