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Collapsing vs: Non-Collapsing BGA Balls |
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lsday 
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 Topic: Collapsing vs: Non-Collapsing BGA BallsPosted: 06 Apr 2016 at 7:37am |
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How does one know if the BGA (CSP) has collapsing or non-collapsing solder balls?
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Tom H
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Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5718 |
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Posted: 06 Apr 2016 at 7:44am |
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Non-collapsing BGA's normally are 0.50 mm pitch or less. There are various Chip Scale Packages where the mfr. calls the package a BGA but instead of a Ball there is only a bump. This is also a non-collapsing BGA. All other BGA's are Collapsing Balls.
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lsday
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Posted: 06 Apr 2016 at 9:09am |
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Thank you for the clarification Tom.
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Tom H
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Posted: 30 Jun 2016 at 7:21am |
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This is what a Collapsing BGA Ball looks like -  Here is a non-collapsing BGA ball with a solder mask defined pad. IPC has guidance to avoid this, but it's impossible for pin pitches below 0.65 mm if there are traces on the same layer.  |
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Eng. Jesus Mora
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Posted: 10 Aug 2018 at 10:12am |
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Hello Tom,
For fine pitch BGA's using the non-collapsing ball in PCB Library expert program we always have default Solder mask expansion of 0 mils. Do you recommend for all fine-pitch non-collapsing ball to use 0 mils expansion? or what is your recommendation for SM expansion in these cases? Thanks
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Tom H
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Posted: 10 Aug 2018 at 11:34am |
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Non-collapsing BGA balls start at 0.50 mm pitch and less.
The pad size is larger because you need to do via-in-pad and you need an annular ring. The solder mask swell = 0 or even -0.05 mm to solder mask define. Even if you can use 2 mil trace/space to escape the second rows, the solder mask must always cover the trace to avoid solder bridging between trace and pad. A 0.50 mm pitch non-collapsing ball size average is 0.25 mm diameter with a pad of 0.33 mm diameter. This leaves a 0.17 mm gap between pads. 0.05 mm trace/space = 0.15 mm but you must consider a 0.025 mm tolerance on the solder mask registration.  |
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