Abstract: The laser beam projection mask 14 has three rectangular-shaped slits 25, 26, 27 as transmission areas. These three slits 25, 26, 27 are formed in sequence in X direction shown by an arrow X in FIG. 2C at specified intervals, and the width in the X direction decreases in the order of the slit 25, the slit 26 and the slit 27. More particularly, transmission coefficients of the transmission areas change in conformity with a temperature distribution curve V1 of a silicon film 4 shown in FIG. 2B.

Abstract: A first laser beam is emitted from a first laser oscillator in a pulsed manner at a high repetition frequency, and converged onto a substrate by a first intermediate optical system 2 so as to form a slit-like first beam spot. A second laser beam is emitted from a second laser beam oscillator in a pulsed manner to rise precedent to and fall subsequent to the first laser beam, and converged onto the substrate by a second intermediate optical system so as to form a second beam spot similar in configuration to the first beam spot and to contain the first beam spot. Crystallization of a semiconductor thin film on the substrate is carried out while the substrate or the first, second beam spots are moved. Thereby, the whole semiconductor thin film is formed into a crystal surface that has grown in one direction and free from ridges. Thus, the semiconductor thin film has an extremely flat surface, extremely few defects, large crystal grains and high throughput.

Abstract: A first laser beam is emitted from a first laser oscillator in a pulsed manner at a high repetition frequency, and converged onto a substrate by a first intermediate optical system 2 so as to form a slit-like first beam spot. A second laser beam is emitted from a second laser beam oscillator in a pulsed manner to rise precedent to and fall subsequent to the first laser beam, and converged onto the substrate by a second intermediate optical system so as to form a second beam spot similar in configuration to the first beam spot and to contain the first beam spot. Crystallization of a semiconductor thin film on the substrate is carried out while the substrate or the first, second beam spots are moved. Thereby, the whole semiconductor thin film is formed into a crystal surface that has grown in one direction and free from ridges. Thus, the semiconductor thin film has an extremely flat surface, extremely few defects, large crystal grains and high throughput.

Abstract: A first laser beam is emitted from a first laser oscillator in a pulsed manner at a high repetition frequency, and converged onto a substrate by a first intermediate optical system 2 so as to form a slit-like first beam spot. A second laser beam is emitted from a second laser beam oscillator in a pulsed manner to rise precedent to and fall subsequent to the first laser beam, and converged onto the substrate by a second intermediate optical system so as to form a second beam spot similar in configuration to the first beam spot and to contain the first beam spot. Crystallization of a semiconductor thin film on the substrate is carried out while the substrate or the first, second beam spots are moved. Thereby, the whole semiconductor thin film is formed into a crystal surface that has grown in one direction and free from ridges. Thus, the semiconductor thin film has an extremely flat surface, extremely few defects, large crystal grains and high throughput.

Abstract: The laser beam projection mask 14 has three rectangular-shaped slits 25, 26, 27 as transmission areas. These three slits 25, 26, 27 are formed in sequence in X direction shown by an arrow X in FIG. 2C at specified intervals, and the width in the X direction decreases in the order of the slit 25, the slit 26 and the slit 27. More particularly, transmission coefficients of the transmission areas change in conformity with a temperature distribution curve V1 of a silicon film 4 shown in FIG. 2B.