摘要 |
<p>CORRECTION OF LITHOGRAPHIC MASKS A lithographic mask is corrected by ion beam removal of material at the location of a defect after the mask is initially formed. In the case of defects due to excess material (opaque defects), the ion beam removes the excess opaque material. In the case of pinholes (clear defects), the substrate (typically glass) is rendered opaque. The ion beam may be used for imaging the defect, typically by detection of secondary electrons or photons emitted where the ion beam impinges on the mask. Optical masks (visible, ultraviolet) and X-ray masks, among others, can be corrected.</p> |