Wafer cutting device and method

A wafer cutting method using a wafer cutting device which comprises an etching unit, a gas supply unit and a chemical reaction liquid supply unit, the method comprising:

• a loading step for fixing a wafer to be cut on a carrier tray;
• an adjusting step for adjusting a distance between a guide shroud and the carrier tray;
• and
• a gas supplying step for supplying a shielding gas to an inner layer and a second hollow interlayer of the guide shroud by the gas supply unit to maintain a constant pressure in the inner layer and the second hollow interlayer, to make a pressure of the inner layer smaller than a pressure of the second hollow interlayer, and to make a pressure of the second hollow interlayer larger than an external pressure of the guide shroud, and to provide a shielding gas to the carrier tray via a gas passage and air holes, so that the shielding gas flows through the air holes toward an edge of the wafer to be cut;
• an etching step for supplying a chemical reaction liquid to the first hollow interlayer of the guide shroud by the chemical reaction liquid supply unit, so that the chemical reaction liquid flows to a portion of the wafer to be cut which locates more external than a portion being under the guide shroud, so as to perform a wet etching on the wafer to be cut and obtain a target wafer;
• a cleaning step for switching the chemical reaction liquid in the chemical reaction liquid supply unit to ultrapure water, feeding it into the first hollow interlayer of the guide shroud to remove a residual chemical reaction solution on a surface of the target wafer;
• a drying step for increasing a pressure and a flow rate of the shielding gas fed into the second hollow interlayer of the guide shroud so as to dry the target wafer;
• and
• a picking step for lifting the guide shroud and pick up the target wafer from the carrier tray.