Defect inspection apparatus, substrate bonding apparatus, and defect inspection method

A defect inspection method comprising:

• holding a substrate having a first principal surface;
• emitting infrared rays from an infrared ray emitter and heating the substrate in a non-contact manner;
• moving a heat insulator capable of absorbing the infrared rays between a heat insulation position and a retracted position;
• executing at least one of a first defect inspection of imaging an imaging region on the first principal surface by an infrared camera in a state where the heat insulator is at the heat insulation position and a second defect inspection of imaging the imaging region on the first principal surface by the infrared camera in a state where the heat insulator is at the retracted position;
• and
• selecting whether or not to execute each of the first defect inspection and the second defect inspection,
• wherein the heat insulation position is a position where the heat insulator and the imaging region overlap each other when viewed from a normal direction of the first principal surface, and the retracted position is a position where the heat insulator and the imaging region do not overlap each other when viewed from the normal direction.