solder mask layer question
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robhoeye 6 years ago
Is there a notion of a solder mask layer? If it not explicitly defined for the pads of an SMT part from which layer is it inferred? Is the current solder mask layer a positive or negative layer? How do i specify the areas of an SMT device pads to not be covered by the masking (Green) coating? Thanks Rob
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dillon 6 years ago
Hi Rob, EasyEDA has solder mask layer, we use a Intelligent way to solve the Pads' solder and paster layer. If you need to add your personal solder and paster layer, please check https://easyeda.com/Doc/Tutorial/PCB.htm#LayersTool. >Is the current solder mask layer a positive or negative layer? negative. solder object, never be green. >How do i specify the areas of an SMT device pads to not be covered by the masking (Green) Yes, you can add a solder object, like a rect, make sure you have config the layer, and make it visible. I add an example, the blue arrow is solder rect, you can check the photoview, this is a copper area , will never be covered with green. If you have any problems, please let us know. BTW, EasyEDA can PCBA for U. when you order a PCBA , you will get a realy product, not only PCB. ![enter image description here][1] [1]: http://i.imgur.com/i9o25Es.png
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andyfierman 6 years ago
Rob, Can I make sure we understand your question: "How do i specify the areas of an SMT device pads to not be covered by the masking (Green) coating?" Suppose you want a clearance of Zmm around all your pads. Are you asking if there is a way to specify the paste mask clearance so that for a pad of Xmm * Ymm then the hole in the paste mask is automatically set to (X+2*Z)mm * (Y+2*Z)mm? Thanks.
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andyfierman 3 years ago
0.75mm clearance around a pad for a BGA ball sounds way too big! That would make the outer diameter of aperture in the solder mask equal to the pad diameter + 1.5mm. * Please check your dimensions. `...decrease the necessary pad side...` I assume you mean decrease '...the necessary pad **size**...'. `...from 0.5mm to 0.45mm...` The recommended reduction in pad size is 20% smaller than the ball diameter. See: https://macrofab.com/blog/bga-pad-creation-smd-nsmd/ So if the **solder ball diameter** was 0.5mm then that would make the **pad diameter** 0.4mm. * If you look at the solder mask aperture that you have created in Photo View then it renders incorrectly and looks as if the whole area of the aperture is filled with copper. This is a bug in Photo View. If you generate and then check the Gerber files in a Gerber Viewer such as: https://gerber-viewer.easyeda.com/ or gerbv: http://gerbv.geda-project.org/ you will see that the correct aperture is created without adding any extra copper. I suggest you create a simple PCB with a pad and a track going to it and then add a solder mask aperture. Then generate the gerbers for it and check them to verify this. I have raised a Bug Report for this. * EasyEDA will automatically set the required solder mask spacing.
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krissol82 3 years ago
I´m wondering about the same thing. To make as small pads as possible for BGA components, they should have a 0.75mm mask clearance around the pads (NSMD), so the solder balls can also attach around the pad. This decrease the necessary pad side on a 1mm pitch BGA from 0.5mm to 0.45mm and will make it a lot easier to escape the BGA with the 0.3mm drill vias and 6mil traces. I tried to mask around one pad (with an arc), but this fills the masked area with copper. See attached photo: I really wish you could make a change so this could be possible! ![BGA with NSMD non-solder mask clearance][1] [1]: /editor/20171202/5a21ab229d67d.png
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krissol82 3 years ago
Hi. Thanks. Yes, I refered to the Photo View showing copper fill. And I wrote incorrectly. I ment 0.075mm. My documentation recommend 0.45mm pad size for 5mm ball, with a solder mask clearance of 0.075mm (Total 0.6mm solder mask diameter on each pad) But maybe I could make them even a little smaller based on your link. I´ll have a look at the gerber files tomorrow. It would be very nice if this would override the automatic soldermask and make it possible to make NSMD pads.
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