set_pin_physical_constraints中，-depth是什么意思

xpw

set_pin_physical_constraints -pin_name {ARADDR} -layers {metal3} -width 0.05 -depth 0.05 -side 3 -order 1上面这个命令中，-depth是什么意思？是金属层厚度吗？这个值怎么定呢？
没看懂man说的：
-depth pin_depth
             Specifies the depth in microns. If the depth  constraint specified  is smaller than minLength defined in the tech file, then the value of minLength will be  honored. If  minArea  is  also defined  in the tech file, then the value of pin depth times pin width should also honor minArea. The default is 0.