US 5,859,707 A · Position detection apparatus and aligner comprising same

Abstract

Position-detection apparatus (alignment sensors) are disclosed for determining the position of an object (e.g., wafer, bearing a position-detection mark) as required in microlithography processes for manufacturing semiconductor devices and displays. The apparatus comprises an irradiation optical system, a condenser optical system, a first photoelectric detector, a fiducial body bearing a fiducial mark, a combining optical system, a second photoelectric detector, and a processor. The position-detection and fiducial marks are illuminated with coherent illumination light from the irradiation optical system. Light diffracted from the marks is condensed by the condenser optical system. The first photoelectric detector receives the condensed diffracted light and produces first electrical signals. The combining optical system receives the diffracted light from the fiducial mark. The second photoelectric detector receives multiple diffracted light beams from the fiducial mark and produces second electrical signals. From the electrical signals, the processor determines the position of the position-detection mark relative to the fiducial mark.

Claims36

Dependent claims

An apparatus for determining the position of an object, comprising:

(a) an irradiation optical system operable to produce at least one beam of coherent illuminant light;
(b) a processor;
(c) first and second photoelectric detectors connected to the processor;
(d) a fiducial body defining a first fiducial mark;
(e) a condenser optical system and a combining optical system, the condenser optical system (i) being situated so as to direct the beam of coherent light from the irradiation optical system through the combining optical system to the first fiducial mark and through the fiducial body to a position-detection mark formed on the object being detected, and (ii) directing at least one beam produced by the position-detection mark and passing through the combining optical system to the first photoelectric detector, the first photoelectric detector converting light received thereby into first electric signals;
and
(f) the first fiducial mark producing multiple diffracted beams that pass through the combining optical system and at least a portion of the condenser optical system to the second photoelectric detector, the second photoelectric detector converting light received thereby into second electric signals, the processor receiving the first and second electric signals and determining from said signals the position of the object.

4 more elements

An apparatus for determining the position of an object, the apparatus comprising:

(a) a condenser optical system having an optical axis and being operable to condense at least one light beam from a position-detection mark formed on a surface of the object being detected;
(b) a first photoelectric detector operable to receive the condensed light beam from the position-detection mark and to photoelectrically convert the received light into first electrical signals;
(c) a first fiducial body, situated between the detected object and the condenser optical system, comprising a surface bearing a first fiducial mark, the first fiducial mark being a source of at least two diffracted beams that pass through at least a portion of the condenser optical system;
(d) a second photoelectric detector operable to receive the diffracted beams from the first fiducial mark and to photoelectrically convert the received light beams into second electrical signals;
and
(e) a processor operable to receive the first and second electrical signals and determine from said signals the position of the position-detection mark relative to the index mark.

3 more elements

Dependencies are inferred from the claim text.

Position detection apparatus and aligner comprising same

Life of this patent

Position detection apparatus and aligner comprising same

Life of this patent

Abstract

Claims36