Laser irradiation apparatus, laser irradiation method, and method for manufacturing semiconductor device

A laser irradiation method for applying laser light to an object to be processed by conveying the object to be processed using a conveyance unit while levitating the object to be processed using a levitation unit, comprising:

• (a) holding, by a holding mechanism, the object to be processed by absorbing the object to be processed;
• (b) conveying, by a moving mechanism, the object to be processed by moving the holding mechanism holding the object to be processed;
• and
• (c) applying the laser light to the object to be processed while the moving mechanism is moving the holding mechanism, wherein
• the holding mechanism comprises:
• a base including:
• a first surface serving as an absorption surface on which the object to be processed is absorbed;
• a second surface opposite to the first surface;
• and a plurality of through holes extending from the first surface to the second surface;
• the first surface of the base being divided along the conveyance direction of the conveyance unit into a plurality of divided first surfaces, and the through hole being provided on each of the plurality of divided first surfaces;
• a plurality of pipes each of which is connected to a respective one of the plurality of through holes on the second surface of the base;
• an evacuation mechanism for evacuating air from the plurality of pipes;
• and
• a plurality of absorption assistance valves each of which is disposed in the middle of a respective one of the plurality of pipes, each of the plurality of absorption assistance valves being configured to be closed when a flow rate of a gas flowing into the pipe through the through hole becomes equal to or higher than a threshold.

A method for manufacturing a semiconductor device, comprising the steps of:

• (A) forming an amorphous film over a substrate;
• and
• (B) crystallizing the amorphous film by applying laser light to the amorphous film, wherein
• the step (B) is a step of applying the laser light to the amorphous film by conveying the substrate using a conveyance unit while levitating the substrate using a levitation unit, and comprises:
• (a) holding, by a holding mechanism, the substrate by absorbing the substrate;
• (b) conveying, by a moving mechanism, the substrate by moving the holding mechanism holding the substrate;
• and
• (c) applying the laser light to the substrate while the moving mechanism is moving the holding mechanism, and
• the holding mechanism comprises:
• a base including:
• a first surface serving as an absorption surface on which the substrate is absorbed;
• a second surface opposite to the first surface;
• and a plurality of through holes extending from the first surface to the second surface;
• the first surface of the base being divided along the conveyance direction of the conveyance unit into a plurality of divided first surfaces, and the through hole being provided on each of the plurality of divided first surfaces;
• a plurality of pipes each of which is connected to a respective one of the plurality of through holes on the second surface of the base;
• an evacuation mechanism for evacuating air from the plurality of pipes;
• and
• a plurality of absorption assistance valves each of which is disposed in the middle of a respective one of the plurality of pipes, each of the plurality of absorption assistance valves being configured to be closed when a flow rate of a gas flowing into the pipe through the through hole becomes equal to or higher than a threshold.