In the present invention, each laser light emitted from a plurality of lasers is divided, and laser light including at least one laser light that is emitted from a different laser and that has different energy distribution is synthesized with another such laser light, or laser light including at least one laser light that has different energy distribution is synthesized with another such laser light through a convex lens that is set at an angle to the direction each laser light travels, to form laser light having excellent uniformity in energy distribution.

Laser irradiation method, laser irradiation apparatus, and method of manufacturing a semiconductor device

At edges of laser light on an irradiation surface or in the vicinity thereof, the energy density is attenuated gradually due to aberration of a lens or the like. Since such regions (attenuation regions) do not have enough energy density for annealing of an irradiation object, uniform annealing of the irradiation object is not possible. In the present invention, one of the plural laser beams is divided into two laser beams so that each section of the two laser beams serves as an edge of the resultant laser light. Each attenuation region of the two laser beams is synthesized with an attenuation region of another laser beam. In this way, laser light every part of which has an energy density suitable for satisfactory annealing of an irradiation object can be obtained from plural laser beams having attenuation regions.

Laser irradiation apparatus, laser irradiation method, and method of manufacturing a semiconductor device

In a raster output scanner, a system for using one original beam and one facet of a rotating polygon to generate two consecutive scan lines. The original beam is first separated into two beams (24, 25) in a beam splitter (21). The resultant beams are polarized ninety degrees apart, and directed to an acousto-optic (A/O) modulator (22). The beams are a sufficient distance apart so that the A/O modulator can modulate each beam with a minimum of crosstalk. The output beams are then brought together to within one scan line separation by a beam recombiner (23), which is a reversed beam splitter. The beams can be brought together to this close proximity without optical interference because the beams are polarized ninety degrees apart.

Multiple beam optical modulation system

An optical beam scanning system is constructed with less optical elements. A light beam (B₁) of parallel rays passes through a first image forming system (L₁). The first image-forming system consists of a cylindrical lens (2) having a refracting power in a direction equivalent to a main scanning direction (X) and a spherical convex lens (3). Focuses of the cyiindrical lens and the spherical convex lens are within a prescribed allowance. A light beam (B₁₁) passing through the spherical lens has a character of parallel rays within a vertical plane and a character of convergent rays within a horizontal plane to be focused on a deflection surface (4a). A reflected light beam (B₂) is finally focused on a surface-to-be-scanned (8) through a second image-forming system (L₂).

Optical beam scanning system

It is an object of the present invention to provide a laser irradiation apparatus being able to irradiate the irradiation object with the laser beam having homogeneous energy density without complicating the optical system. The laser irradiation apparatus of the present invention comprises a laser oscillator, an optical system for scanning repeatedly a beam spot of the laser beam emitted from the laser oscillator in a uniaxial direction over the surface of the irradiation object, and a position controlling means for moving the position of the irradiation object relative to the laser beam in a direction perpendicular to the uniaxial direction.

Laser irradiation apparatus and method for manufacturing semiconductor device

An uncomplicated system for exposing a recording medium by scanning the medium with laser light to form a clear, uniformly dense recording pattern without interference.

Scanning/recording system with plural beam overlap without interference

A laser exposure apparatus of an image scanning 
recording apparatus comprises a single laser light source 
2, a beamsplitter 3 for dividing a laser beam emitted from 
the single laser light source 2 into two laser beams, a 
modulator 7, 8 for modulating two laser beams in 
accordance with a recording signal, a half-wave 
retardation plate 9 for polarizing one of the beams in 
association with the other one of the beams so that the 
modulated laser beams constitute a pair of orthogonal 
polarization, a polarizing beamsplitter 10 for arranging 
two beams constituting a pair of orthogonal polarization 
with each other orthogonally in a line, and an optical 
system 11 for reducing the laser beams arranged in a line.

Masahide Okazaki

Papers

Scanning/recording system with plural beam overlap without interference

Method and apparatus for laser exposure in an image scanning/recording apparatus