本发明的目的是提供一种激光照射设备，此设备与使用连续振荡的激光的设备相比，能够大幅度地扩展光束点的面积，并抑制对玻璃基板的热损伤，且能够使结晶面向扫描方向连续地长大，形成由沿该扫描方向延长的单结晶构成的晶粒群。本发明的激光照射设备的特征是包括激光振荡器，用以转变从激光振荡器中发射出来的脉冲振荡激光光的波长的非线性光学组件；以及用以将其波长被转变了的激光光束聚光到半导体膜上的光学系统，其中，脉冲重复率是在10MHz至100GHz的范围中。

The object of the present invention is to provide a laser irradiation apparatus being able to enlarge the beam spot to a large degree compared with that of the CW laser, to suppress the thermal damage to the glass substrate, and to form an aggregation of crystal grains including a single crystal extending long in a scanning direction by growing the crystal continuously in the scanning direction. The laser irradiation of the present invention comprises a pulsed laser oscillator, a non-linear optical element for converting the wavelength of the laser light emitted from the pulsed laser oscillator, and an optical system for condensing the laser light whose wavelength is converted on a semiconductor film, wherein the pulsed laser oscillator has a repetition rate in the range of 10 MHz to 100 GHz.