Physical Design: Flipping hard macros

[pradeeppiskala]

Can we flip hard macros on x and y direction? flip (mirror image along x and y). Flip is different from rotate.

Thanks

 

[rca]

A flip is two consecutive rotations.

 

[pradeeppiskala]

Could you please check the diagram in the attachment if I am right about flip and rotate 180. Are both of them allowed?

Thanks

 

[yadavvlsi]

It depends on which technology you are working on. 45nm & below there are orientation requirements by foundry. Poly orientation should be same throughout the chip. So Macro poly orientation should match with the poly orientation of the standard cells.

 

[rca]

Then the LEF file indicate with the "SYMMETRY" key word, which it is allow "X" or "Y", flipping and "R90" for rotation.
Also as exemple, as indicate by yadavvsli, the flash instance provided by TSMC in 0.18um, if multiple instances are needed, all must be with the same orientation.