| 摘要 |
The invention refers to a method for exposing a layout comprising multiple layers on a wafer, in which at least one layer is exposed photolithographically and subsequently at least one further layer is exposed with an electron beam, and the wafer is to be aligned in defined fashion with respect to the electron beam exposure system in terms of the previously photolithographically exposed layer. It is provided according to the present invention that before electron beam exposure begins, an alignment of the wafer (global alignment) is performed on the basis of structural features that were previously generated on the wafer by photolithographic exposure. For example, the wafer is first positioned coarsely in such a way that a surface area having selected structural features is located in the deflection region of the electron beam. That surface area is then scanned in spot fashion with the electron beam, and from the intensities of the radiation backscattered from the individual spots, a raster image is obtained and is compared to a raster image (template) of the same surface area with the wafer in the reference position. From the deviation, positioning instructions are generated to change the position of the wafer so as to bring the actual position closer to the reference position.
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