total depth 156 of the trench to be created 156 may be between approximately 1 0 u03bcm and 750 0 u03bcm in certain embodiments total dose or cumulative etch time 158 may be given as a rate of beam energy applied in nano coulombs per square micron nc u03bcm 2 and may be between approximately 1 0 nc u03bcm 2 and 10 0 nc u03bcm 2 while the number of boxes desired 160 may vary widely in different embodiments between approximately 10 and 100 boxes may be formed in certain embodiments in various embodiments a conventional fib tool may be used to form a trench such a conventional fib tool may be located in a chamber typically constructed of aluminum or steel and having a suitable inside volume to house a semiconductor wafer in certain embodiments the chamber may also be provided with a heat source vacuum and gas sources and the like in forming trenches and other features in accordance with the present invention conventional temperatures pressures and tool energies may be used of course in other embodiments other parameters may be similarly suitable in one embodiment the fib tool may be a micrion 9800fc column produced by fei corporation hillsboro oreg in one example embodiment of a process.