Acid Traps are generated when a gap from pad to trace is too small. They can be avoided by increasing the gap or moving the trace so that it exits the pad lower down the pad. Or you can use a gloss command to add a fillet from the pad exit.
In reply to steve:
Thanks Steve ,
Could you please show any example & how to use Gloss command allegro designL 16 ver supports this?
In reply to girish:
Screenshot attached. I'm afraid you'll need Allegro Performance and above to do this with Gloss.
What's the problem from these acid traps? Can it be changed the signal shape? I also faced same problem. Please help.
In reply to C Shiva:
During cleaning of board chemicals may deposite there. thats why we have to route straight to minimize the probability.
In reply to pakistan:
Acid trap always occur on every PCB boards especially high density PCB's.This may result to a short circuit due to the un-etched copper.
Here are some rules to avoid this
1.minimize using trace connection less than 45deg vertex.
2.always remove those isolated plane island
3.minimize goup vias with a less spacing surrounded by traces
4.add some via holes to the area were your acid trap located so the chemical can escape thru the other side
But believe me as far as i know there is no such design that free from acid trap especially multilayer boards.There is no specs define for this.
Hope this can helps.