Patent ID: 8591697

Claim:
A mask fixture for etching an item, the mask fixture comprising: a top fixture disposed over the item, the top fixture comprising a reservoir centered within the top fixture; a bottom fixture underneath the item to be etched, the bottom fixture comprising a recessed surface area centered within the bottom fixture; an etch-resistant window for holding the item, wherein the etch-resistant window is disposed within the recessed surface area such that the etch-resistant window fits entirely within the recessed surface area and does not extend above the bottom fixture when situated in the recessed surface area; a small via centered within and intersecting both the top and bottom fixtures, defining a path for a high intensity light beam; a high intensity light source projecting the high intensity light beam upwards through the small via onto the item, wherein said high intensity light beam becomes visible from above, through the etched item, when the item is thinned by the etching to a thickness of tens of microns, thus becoming transmissive to light; and an interconnect for coupling the top and bottom fixtures such that a tight seal is created around the item to be etched when the top and bottom fixtures are coupled.