Part Numbering - STMicroelectronics STPS2L40UF

What does the suffix F call out in STMicroelectronics part STPS2L40UF? How is it different from STPS2L40U?

The F calls out a FLAT package, which is the same footprint, but about half the height of the base part.

STPS2L40U

STPS2L40UF