PCB Libraries Forum : BGA PAD Mask Definition https://www.PCBLibraries.com/forum/ Tue, 07 Apr 2026 12:28:13 +0000 Wed, 17 May 2023 08:37:41 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=3271 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[BGA PAD Mask Definition : Altium has its own Preference...]]> https://www.PCBLibraries.com/forum/bga-pad-mask-definition_topic3271_post13039.html#13039 Author: Tom H
Subject: 3271
Posted: 17 May 2023 at 8:37am

Altium has its own Preference Rules and Solder Mask Swell is one of them. 

UseMaskExpansionRules = no matter what solder mask is defined in Footprint Expert, use the Altium Preference settings. 

In other CAD tools (like PADS Layout), the solder mask defined in Footprint Expert is translated directly across. 

Everyone has there own solder mask swell. 0.05, 0.06, 0.07, 0.075, 0.08, 0.09, 0.10, etc. 

In a typical company PCB Library, every solder mask oversize is the same value. 

However, an example of changing times, Texas Instruments recommended solder mask swell on fine pitch and microminiature packages is 0.05 swell but in larger pin pitches and bigger packages the mfr. recommended solder mask swell is 0.07. 

For BGA's TI recommends rounded corner squares for solder mask. 

There are more and more semiconductors from TI that have complex solder mask shapes. 


 

These semiconductors are becoming more mainstream every day. 


 
]]> Wed, 17 May 2023 08:37:41 +0000 https://www.PCBLibraries.com/forum/bga-pad-mask-definition_topic3271_post13039.html#13039 <![CDATA[BGA PAD Mask Definition : I get the idea of either a reduction...]]> https://www.PCBLibraries.com/forum/bga-pad-mask-definition_topic3271_post13038.html#13038 Author: mnperry
Subject: 3271
Posted: 17 May 2023 at 6:24am

I get the idea of either a reduction or increase in defining the land pad based on whether I am defining a collapsing or non-collapsing ball / land pattern. This is a percentage.

How is the solder and paste mask (excess) defined?

Is there a manual calculation I have to do in the case of an increase in pad size so the mask will partly cover the land pad?

In the calculator the solder mask excess is 0.00 no matter whether a collapsiong or non-collapsing ball is being used.





Also in the CAD translator, I see this. What is the UseMaskExpansionRules for?



I suspect I am missing something obvious.

Thanks.

]]> Wed, 17 May 2023 06:24:01 +0000 https://www.PCBLibraries.com/forum/bga-pad-mask-definition_topic3271_post13038.html#13038