Abstract:
The laser irradiation apparatus of the present invention is configured to include a laser and at least two mirrors each having a concave surface for unidirectionally homogenizing an energy density of laser light emitted from the laser. A focal position of a first mirror exists between the first mirror and an irradiation surface. A focal position of a second mirror does not exist between the second mirror and the irradiation surface, but exists behind the irradiation surface. The laser irradiation apparatus thus configured enables laser irradiation of, for example, semiconductor films.
Abstract:
In an annealing process of illuminating a semiconductor thin film with laser light, in the case where the laser illumination is performed at an energy level that is lower than an output energy range that allows a laser apparatus to operate most stably, the laser output is fixed somewhere in the above output energy range and the illumination energy is changed by inserting or removing a light attenuation filter into or from the laser illumination optical path. As a result, the time required for the laser processing can be shortened.
Abstract:
In an annealing process in which laser light is irradiated to a semiconductor thin film, a refractive index of the semiconductor thin film after laser light irradiation is measured and conditions for the next laser light irradiation are adjusted based on the measured refractive index value. For example, laser light irradiation conditions are adjusted so that semiconductor thin films always have the same refractive index. As a result, the annealing can be performed under the same conditions at every laser light irradiation even if the laser light irradiation conditions vary unavoidably.
Abstract:
It is an object to provide a laser irradiation apparatus for enlarging an area of a beam spot and reducing a proportion of a region with low crystallinity. It is also an object to provide a laser irradiation apparatus for enhancing throughput with a CW laser beam. Furthermore, it is an object to provide a laser irradiation method and a method for manufacturing a semiconductor device with the laser irradiation apparatus. A region melted by a first pulsed laser beam having harmonic is irradiated with a second CW laser beam. Specifically, the first laser beam has a wavelength of visible light or a shorter wavelength than that of visible light (approximately not more than 830 nm, preferably, not more than 780 nm). Since the first laser beam melts a semiconductor film, an absorption coefficient of the second laser beam to the semiconductor film increases drastically and thereby being more absorbable.
Abstract:
It is an object to provide a laser apparatus, a laser irradiating method and a manufacturing method of a semiconductor device that make laser energy more stable. To attain the object, a part of laser beam emitted from an oscillator is sampled to generate an electric signal that contains as data energy fluctuation of a laser beam. The electric signal is subjected to signal processing to calculate the frequency, amplitude, and phase of the energy fluctuation of the laser beam. The transmittance of a light amount adjusting means is controlled in order that the transmittance changes in antiphase to the phase of the energy fluctuation of the laser beam and with an amplitude capable of reducing the amplitude of laser beam emitted from the oscillator, the control being made based on the phase difference between the phase of a signal that is in synchronization with oscillation of laser beam emitted from the oscillator and the phase calculated, on the energy ratio of the sampled laser beam to laser beam emitted from the oscillator, and on the frequency and amplitude calculated. In the light amount adjusting means, energy of the laser beam oscillated from the oscillator energy is adjusted.
Abstract:
There is provided an optical system for reducing faint interference observed when laser annealing is performed to a semiconductor film. The faint interference conventionally observed can be reduced by irradiating the semiconductor film with a laser beam by the use of an optical system using a mirror of the present invention. The optical system for transforming the shape of the laser beam on an irradiation surface into a linear or rectangular shape is used. The optical system may include an optical system serving to convert the laser beam into a parallel light with respect to a traveling direction of the laser beam. When the laser beam having passed through the optical system is irradiated to the semiconductor film through the mirror of the present invention, the conventionally observed faint interference can be reduced. Besides, the optical system which has been difficult to adjust can be simplified.
Abstract:
A method for producing a thin-film transistor by using a crystalline silicon film that has been formed by using nickel as a metal element for accelerating crystallization of silicon. In forming source and drain regions, phosphorus as an element for gettering nickel is introduced therein by ion implantation. Nickel gettering is effected by annealing. For example, in the case of producing a P-channel thin-film transistor, both phosphorus and boron are used. Boron determines a conductivity type, and phosphorus is used as a gettering material.
Abstract:
An object of the present invention is to provide a method and a device for constantly setting the energy distribution of a laser beam on an irradiating face, and uniformly irradiating the laser beam to the entire irradiating face. Further, another object of the present invention is to provide a manufacturing method of a semiconductor device including this laser irradiating method in a process. Therefore, the present invention is characterized in that the shapes of plural laser beams on the irradiating face are formed by an optical system in an elliptical shape or a rectangular shape, and the plural laser beams are irradiated while the irradiating face is moved in a first direction, and the plural laser beams are irradiated while the irradiating face is moved in a second direction and is moved in a direction reverse to the first direction. The plural laser beams may be irradiated while the irradiating face is moved in the first direction, and the plural laser beams may be irradiated while the irradiating face is moved in the direction reverse to the first direction, and the irradiating face may be also moved in the second direction.
Abstract:
Laser annealing is performed by irradiating, while scanning, a semiconductor thin-film with laser light. The laser light that is linear on the irradiation surface is moved in its line-width direction and applied non-continuously. The laser light has, in its line-width direction, an energy density profile that assumes a step-like form in which the energy density varies in a step-like manner. In particular, the scanning pitch D and the step widths Ln are so set as to satisfy a relationship LnnullD.
Abstract:
There are disposed two homogenizers for controlling an irradiation energy density in the longitudinal direction of a laser light transformed into a linear one which is inputtted into the surface to be irradiated. Also, there is disposed one homogenizer for controlling an irradiation energy density in a width direction of the linear laser light. According to this, the uniformity of laser annealing can be improved by the minimum number of homogenizers.