| 摘要 |
<p>Long wavelength light from a first light source and short wavelength light from a second light source are collected at a beam splitter, and this collected light is made to converge by a lens and is incident to a mask and substrate perpendicular to the surfaces thereof. Furthermore, this collected light is reflected by mask alignment marks and substrate alignment marks, returns along the light path of the incidence, passes through a filter, and is incident to a camera. The filter forms images of the long wavelength light and short wavelength light in the reflected light in different regions on a sensor in the camera. Thus, the camera can observe the patterns of the alignment marks that are focused on for both the mask and the substrate simultaneously. Therefore, even if the light path is offset from the optical axis, changes in the relative position of the patterns for the substrate alignment marks and mask alignment marks do not arise easily, and the alignment precision is high.</p> |
