초록 ▼

An automatic focus control device for adjusting the height of a lens above a surface of a workpiece used in an exposure apparatus for exposing the sample with a light beam including a first light emitting device for emitting a first light ray to a sample; a second light emitting device for emitting

An automatic focus control device for adjusting the height of a lens above a surface of a workpiece used in an exposure apparatus for exposing the sample with a light beam including a first light emitting device for emitting a first light ray to a sample; a second light emitting device for emitting a second light ray to the sample. First and second light detecting devices for detect the second and first light rays reflected by a surface of the sample, respectively. The first and second light detecting device have a plurality of light detecting elements. A discriminating device discriminating between an inclination of the sample and a variation of the height of the lens above the surface of the sample on the basis of an output of the first and second light detecting devices. The first light emitting device and the first light detecting device are symmetrically located with respect to the second light emitting device and the second light detecting device in relation to a center axis of a light beam for exposing the sample.

대표청구항 ▼

An automatic focus control device used in an exposure apparatus comprising: a first light emitting means for emitting a first light ray to a workpiece; a second light emitting means for emitting a second light ray to said workpiece; a first light detecting means for detecting said second light ray r

An automatic focus control device used in an exposure apparatus comprising: a first light emitting means for emitting a first light ray to a workpiece; a second light emitting means for emitting a second light ray to said workpiece; a first light detecting means for detecting said second light ray reflected by a surface of said workpiece, and said first light detecting means having a plurality of light detecting elements; a second light detecting means for detecting said first light ray reflected by said surface of said workpiece, said second light detecting means having a plurality of light detecting elements; and discriminating means, operatively connected to said first and second light detecting means, for discriminating between an inclination of said workpiece and a variation of focus on the surface of said workpiece on the basis of outputs of said first and second light detecting means; wherein said first light emitting means and said first light detecting means are symmetrically located with respect to said second light emitting means and said second light detecting means in relation to said surface of said workpiece.