A Waffle slab is a type of reinforced concrete flooring system. It is recommended for buildings that require minimal vibration.
[1] - https://en.wikipedia.org/wiki/Waffle_slab

For example, the floor of a cleanroom in a semiconductor fab is typically built as a deep concrete waffle slab two to four feet thick!
[2] - https://www.construction-physics.com/p/how-to-build-a-20-billion-semiconductor