TWI709451B

The invention relates to a method and a device for processing a multilayer substrate by a laser beam. The multilayer substrate can be processed with the simple structure in the condition that the cost of the device does not increase. The processing method processes the multilayer substrate by illuminating the laser beam, and comprises a preparation step and a processing step. In the preparation step, at least a first layer of the multilayer substrate and a second layer of the multiplayer substrate which are laminated are prepared. In the processing step, the first layer and the second layer are simultaneously processed by illuminating the laser beam with the wavelength that can process the first layer from the first layer side, has penetrable specific absorptivety relative to the first layer, and can process the second layer.