VARIABLE STEP HEIGHT CONTROL OF LITHOGRAPHIC PATTERNING

摘要

A method and apparatus for forming layers of photo-sensitive materials in different thicknesses. A mask (102) including a first area (102a) that substantially blocks light transmission and a second area (102d) having optical characteristics, which partially blocks light transmission is employed. Light (101) is projected through the mask (102) onto a layer of photo-sensitive material (107). The first area (102a) substantially blocks the light from passing through and leaves portions of the photo-sensitive material (107) unexposed. The secondary area (102d) reduces the intensity of light passing through the mask (102) and projected onto other portions of the photo-sensitive material (107). After developing the photo-sensitive material, at least two thicknesses of photo-sensitive material results. The second area (102d) may include a number of sections that vary from each other in optical characteristics such that the intensity of the light projected onto the layer of photo-sensitive material (107) through the second area (102d) varies in steps or continuously.