the member to be freed of the third layer 18 of the metrology structure 10 referring to fig2 3 4 5 and 6 as the third portion 22 is freed from the sacrificial material underneath the layer 18 and the second portion 32 is freed from the sacrificial material underneath and surrounding the layer 16 simultaneously the freed member will be retained in the cage comprising the third portion 24 the second portion 34 and the first portion 42 but will be able to move and drop down within the cage it should be noted that the posts 28 of the layer 18 and the posts 36 of the layer 16 not only provide support for the layers 18 and 16 respectively they also prevent the freed member 22 32 from moving far in a horizontal direction also during the sacrificial material removal process when external forces try to pull the freed member 22 32 to float up the tabs 26 of the third portion 24 of the cage 13 block the second portion 32 of the freed member which in turn is connected to the third portion 22 of the freed member of the layer 18 and hence the possibility of the freed member 22 32 being pulled floated up in a vertical direction and potentially damaging other devices on a wafer is prevented fig1 2 3 4 5 6 7 and 8 are not drawn to scale they provide schematic illustration of certain example embodiments in one embodiment of the invention the cage 13 and members 22 32 and 44 can be made.