the boundary of the supply conduit 20 is 100 u03bcm however this distance is not critical the removal of matter and smoothing of the edge of the segment may be accomplished by sawing the segment and using chemical mechanical polishing cmp as known in the ic manufacturing art however any method known in the ic manufacturing art that will produce a smooth edge 24 at a controlled distance from the undercut 22 may be employed the smooth edge 24 is masked at step 42 with a patterned photoresist to expose at least a portion of the length of the intermediate layer 12 in the present embodiment the length of the exposed intermediate layer 12 is on the order of 100 u03bcm however this dimension is not critical a slot 26 in the intermediate layer 12 at the smooth edge 24 is created using conventional photolithography combined with selective etching techniques the slot has a width dimension e g w 100 u03bcm perpendicular to the thicknesses of the three layers 10 12 and 14 where w is precisely controlled to the resolution of the selected photolithography techniques 100 nm to 1 u03bcm the slot has a depth or thickness dimension d measured in the direction parallel to the thicknesses of the three layers where d is precisely controlled by the selected techniques for forming the intermediate layer 1 nm to 10 nm with reference to fig3 and 4 after the slot is completed a second.