material alternatively the shell 102 may be formed from a material that sublimates rapidly at elevated temperatures compatible with integrated circuit manufacture i e those within a range of about 200 u2013 400 u00b0 c paradichlorobenzene and napthalene are two such common materials the bead cores 101 are employed as elemental masking elements while the shells 102 set or define the spacing between the bead cores 101 spacing between elemental masking elements i e the cores 101 may be adjusted by varying thickness of the shells 102 in the drawings appended to this disclosure beads are depicted for the sake of clarity as though the cores 101 are opaque elements while the shells 102 are depicted as though transparent however nothing should be inferred regarding the type of materials used from the adoption of this illustration convention referring now to fig2 a conductive layer 202 is deposited on a silicate glass plate 201 as conductive layer 202 must be fairly stable during subsequent elevated temperature steps suicides of metals such as titanium tungsten cobalt nickel platinum and paladium may be used a silicon layer 203 also referred to herein as u201c the cathodic layer u201d is deposited over the conductive layer 202 a masking layer 204 is then deposited over the silicon layer 203 the masking layer 204 may be a nitrided material such as silicon nitride titanium nitride or titanium carbonitride a silicide of a refractory metal such as titanium platinum or tungsten or an unreacted metal such as aluminum titanium or copper the primary consideration during the.