| 摘要 |
The present invention provides a wafer fabricating method which irradiates a separation predetermined line with laser beam having permeability for a wafer by locating a light concentration point in the inner side and forms a reforming layer along the separation predetermined line and grinds the rear side of the wafer and forms the wafer with a completion thickness and does not damage a device by preventing corners of the device from being brushed when the wafer is divided into individual devices. The wafer fabricating method divides the wafer in which a device is formed in a plurality of areas divided by the separation predetermined line which formed on the surface as a lattice shape along the separation predetermined line. The wafer fabricating method comprises; a reforming layer forming step which irradiates the separation predetermined line with a laser beam of a wavelength having the permeability for the wafer by fitting the light concentration point and forming a reforming layer which becomes a breaking point inside the wafer along the separation predetermined line; and a rear side grinding step of forming the wafer with a predetermined thickness by grinding the rear side of the wafer and dividing into the individual devices along the separation predetermined line in which the strength is degraded by forming the reforming layer. Before the rear side grinding step is started, a protection member bonding step is executed. The protection member bonding step bonds a protection member which is cooled with a temperature lower than the temperature for executing the rear side grinding step to the surface of the wafer. The protection member is thermally expanded by the increase of the temperature when the rear side grinding step is executed. Therefore, an air gap is formed between the divided device and the device and the contact of the adjacent device is suppressed. |
