| 摘要 |
Disclosed herein are methods for removing overlying materials on a substrate which otherwise might optically obscure an underlying photolithography alignment marker. According to the disclosed techniques, laser radiation is used to remove the material (e.g., a metal) in an area which overlies the alignment marker (e.g., formed in polysilicon). Such removal can comprise the use of laser ablation or laser-assisted etching. The substrate is placed on a motor-controlled chuck in a laser removal chamber, and the areas are automatically moved underneath the laser radiation to removal the material. Alternatively, a stencil having holes corresponding to the areas can be placed over the substrate to mitigate the need to move the substrate to the areas with precision. After clearance of the area, photoresist can then be applied to the material with the alignment marker now visible though the removed area, and the now-visible alignment marker can be used to pattern the photoresist to align the material with the alignment marker (and hence, other active structures formed of the same material as the alignment marker).
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