US 4,794,648 AGranted

Mask aligner with a wafer position detecting device

AssigneeCanon Kabushiki Kaisha

InventorsNaoki Ayata, Yasuyoshi Yamada

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Abstract

A mask aligner includes a TV image pick-up device having a wide field angle and picking up the image of a wafer detection pattern on an image pick-up station to generate TV signals at the output, a fine alignment device for detecting a positional deviation of the wafer relative to a mask in an exposure station with the detected result being used to align the wafer with the mask, a transport stage for carrying and transporting the wafer from the image pick-up station to the exposure station, a processing device for determining the positional deviation of the wafer relative to the reference position on the image pick-up stage in accordance with the TV signals, and a drive for moving the transport stage so as to remove the positional deviation of the wafer relative to the reference position of the exposure station.

Claims6

Dependent claims

A wafer position detecting apparatus, comprising:

projection optical means for exposing a wafer to a circuit pattern of a mask;
first illuminating means, disposed adjacent said projection optical means, for illuminating the wafer without using said projection optical means;
first photoelectric conversion means, associated with said first illuminating means, for detecting a mark on the wafer;
second illuminating means for illuminating the wafer through said projection optical means;
second photoelectric conversion means, associated with said second illuminating means, for detecting a mark on the wafer;
wafer carrying means movable between a first position where a wafer carried thereon is illuminated by said first illuminating means and a second position where the wafer carried thereon is illuminated by said second illuminating means;
and
control means including:
detecting means for detecting the deviation of the mark on the wafer carried by said carrying means from a predetermined reference position by cooperation with said first illuminating means and said first photoelectric conversion means without aligning the mark on the wafer with the predetermined reference position;
and
means for moving said carrying means to the second position in accordance with an output from said detecting means indicative of the detected deviation to allow the wafer to be illuminated and detected by said second illuminating means and said second photoelectric conversion means.

8 more elements

Dependencies are inferred from the claim text.