When designing PCBs, various ways exist to achieve copper balancing and prevent warping during automated soldering. One common method is to use crosshatch planes, which involve creating a pattern of intersecting lines on a plane to even out the copper distribution. However, it's important to note that this approach doesn't provide the same level of EMC benefits as a solid copper plane.
To achieve copper balancing with a solid copper plane, it's crucial to pay attention to the PCB's stack-up and ensure that the plane is symmetrical. Adding copper fills to trace layers is another option. Still, ensuring they are via-ed to an unbroken 0-voltage reference plane at regular intervals is important to prevent worsening EMC.
Regarding crosshatched planes, it's important to remember the associated traces, which are always angled at 45 degrees to the hatched pattern. This can increase mutual inductance and crosstalk, so it's important to reduce the size of the hatch pattern in relation to the trace spacing. A tight crosshatch plane with no traces over a gap or split can significantly reduce crosstalk.
Finally, it's worth noting that copper fills are not the same as planes and can actually worsen a PCB's EMC performance. To prevent this from happening, it's important to link all parts of the fill to an unbroken 0-voltage reference plane via holes at regular intervals. This can help prevent the copper fill from behaving like a series of RF resonators and antennas, ultimately improving the PCB's overall performance