Improving bow and twist in PCB

[rajkumar_avg]

Hi All,

Can anyone assist me this problem with PCB manufacturing.

I made a four layer PCB. The copper in inner layer is impbalace. Now inorder to improve the bow and twist the manufacturer is asking me to add some dummy copper in empty places on layer with the clearance of 40mil. Incase if i add dummy Cu on layer will it affect my PCB impedance or it may cause anyother issue?

If anyone could assist me it wold be appreciated.

-Rajkumar

 

[chinta]

Re: Bow and twist..

Hi Rajkumar,

You can add more copper on inner layers and see that the ratio is very close between the layer 2 and layer 3. This will not affect the impedance. You can fill copper and connect it to the GND on one layer and may be VCC on the other layers. This will help in improving the capacitive affect on the board.

I hope this will help. Any comments are welcome.

 

[cyberrat]

Bow and twist..

If you fill with copper and have it connected to nothing, then this can/will cause EMC issues, connecting it to your 0v/ground would be best.

 

[rajkumar_avg]

Re: Bow and twist..

Thanks for information.

-Rajkumar