Curiously, I had a discussion with a thermal solutions manufacturer during
Computex Taipei, circa-2003/04, about nearly the very same concept that Patent 7282799 - 'Thermal interface with a patterned structure' details. That is, to create very thin, shallow grooves in the base of heatsink to enable the maximal amount of excess thermal interface material to escape from between the heatsink-to-integrated heatspreader contact area.
Physics of course gets the original patent on this, as thermal interface
material will naturally do the same thing, given time, heat and clamping force.
You can see examples of this after removing a heatsink, provided the base of the
heatsink is flat and the clamping forces even. If these conditions exist, you'll
see a pattern in the shape of a X going from corner to corner in the
remaining thermal goo, with fine fractal patterns sub-dividing the remaining
area ad infinitum.
Patent 7282799: Worth the read.