Laser treatment apparatus, laser treatment method, and manufacturing method of semiconductor device

A laser treatment method, using a laser treatment apparatus including a laser oscillator, a first interlock provided in the laser oscillator, a movable table which moves with a certain movement period, a timer, a second interlock provided in the timer, and a sensor which can detect movement of the movable table, the method comprising:

• placing a substrate over the movable table;
• annealing a semiconductor film formed over the substrate with laser light;
• starting measuring time with the timer when the sensor senses passage of the movable table;
• and
• blocking conduction between contacts of the second interlock provided in the timer when the movable table does not pass the sensor even after the movement period to operate the first interlock in the laser oscillator, thereby not irradiating the substrate over the movable table with the laser light.