According to the present invention, in making alignment between a semiconductor integrated circuit wafer and a mask or a reticle in light exposure of the wafer with a monochromatic light such as g-, i- or h- line of a mercury lamp, using a reduced stepping exposure system, light from a predetermined pattern on the wafer is taken out to an off-axis position and observed according to a through-the-lens method; in this case as a characteristic feature of the invention, the observation light is taken out from below the reticle and is passed through chromatic aberration correcting lenses, thereby permitting the use of a polychromatic or continuous spectrum light.

Two pieces of semiconductor wafers 10.sub.1 and 10.sub.2 to be stacked and fused together are secured to wafer holders 20.sub.1 and 20.sub.2 respectively, and are then integrally held at a wafer hold unit 2. Rough position alignment is first applied to these semiconductor wafers 10.sub.1 and 10.sub.2 while supplying infrared light thereto from an infrared light source 30 of an infrared light system 3 for detection of a resultant lattice image at a detection unit 5. Then, fine position alignment is performed while supplying laser light from an laser light source 40 of a laser light system 4 for detection of a resultant diffraction image at the detection unit 5. Thus, in the manufacture of a semiconductor device having its crystal structure with three-dimensional periodical refractive index distribution employing precision multilayer stack methods by using a wafer fusion, a method and apparatus for manufacturing the semiconductor device is realized which is capable of achieving precise position alignment between lattice layers stacked over each other with reduced complexity in position alignment thereof.

A method and a system for pattern detection are disclosed in which a laser beam high in directivity is emitted from a laser beam source, the laser beam emitted from the laser beam source is irradiated on an uneven pattern to be detected on an object, the light component of a frequency corresponding to the cut-off frequency of an objective lens is removed from the light reflected from the object when an image of the pattern on the object is formed through an objective lens, the optical image thus formed is received by a photoelectric converting device for producing a signal waveform representing the pattern free of a signal of the frequency corresponding to the cut-off frequency, and the pattern is detected from a signal produced from the photoelectric converting device.

An alignment apparatus is provided with a first beam receiving device arranged to receive an interference beam which is produced at a diffraction grating of a substrate as a result of illumination with a pair of beams which intersect each other on the substrate, and a second beam receiving device arranged to receive a reference beam which is produced by the interference between regularly reflected beams of the pair of beams occurring on the substrate, wherein the positional offset of the substrate is obtained on the basis of a comparison between the output signal of the first beam receiving device and the output signal of the second beam receiving device. Since a beam transmitting path for transmitting a measurement beam is substantially common to a beam transmitting path for a reference beam, even if the fluctuations of air occur, both the measurement beam and the reference beam substantially equally reflect the influence of the fluctuations, whereby it is possible to cancel the same.

A wafer is aligned by using an alignment light having a longer wavelength than an exposure light. Exposure and alignment are effected through a common reduction lens. A wavefront aberration caused by the use of the long wavelength alignment light is compensated by a hologram. Thus, an alignment precision is improved without exposing a resist layer to a light.