| 摘要 |
PURPOSE:To stabilize the oscillation of a laser while improving the efficiency of heat treatment by projecting laser lights reflected by the surface of a semiconductor wafer to the same point as the projecting point of the laser on the surface of the semiconductor wafer again by using an optical system. CONSTITUTION:Laser lights from a laser 2 are reflected by a reflecting mirror 3, projected to an objective 4, forcussed on the surface of a semiconductor wafer 1 by the objective 4, and projected to the surface of the semiconductor wafer 1 at an angle of 87-88 deg.. The incident lights are reflected by the surface of the semiconductor device 1, and changed into diverged lights. The diverged lights are projected to a lens 5 and converted into parallel lights again, and projected to a reflecting mirror 6 and reflected. Reflected lights from the reflecting mirror 6 are forcussed on the surface of the semiconductor wafer 1 by the lens 5 and projected. Accordingly, since reflected lights from the surface of the semiconductor wafer are projected to the same point on the surface of the semiconductor wafer again, lights returning to the laser are minimized, a change into an unstable state of the oscillation of the laser is reduced, and the amount of light contributing to the heating of the semiconductor wafer is also increased. |
