Wafer processing method

A wafer processing method for processing a wafer that has one side in which an annular protruding portion is provided on an outer circumferential portion thereof and a circular recessed portion is formed in a region surrounded by the annular protruding portion, by a thermocompression bonding apparatus that includes an upper chamber including a first recessed portion that is coupled to a first depressurizing unit and that has a first opening, a lower chamber including a second recessed portion that is coupled to a second depressurizing unit and that has a second opening, and a holding table that is disposed on the second recessed portion and that holds the wafer, the upper chamber and the lower chamber being closed by the first opening and the second opening being fit together, the wafer processing method comprising:

• a holding step of holding the wafer the one side of which is oriented upward, from a lower side by the holding table of the thermocompression bonding apparatus;
• a sealing step of sandwiching a sheet of a frame unit including an annular frame having at a center thereof an opening portion capable of housing the wafer and the sheet fixed to an outer circumferential portion of the annular frame, by the first opening of the first recessed portion and the second opening of the second recessed portion, at an inner side of the opening portion, and closing the first recessed portion and the second recessed portion;
• a depressurizing step of depressurizing the first recessed portion by the first depressurizing unit and depressurizing the second recessed portion by the second depressurizing unit, after the sealing step;
• a contacting step of causing the sheet to come into contact with the annular protruding portion and the circular recessed portion by increasing pressure inside the first recessed portion and causing the sheet to come into contact with the one side of the wafer, after the depressurizing step;
• and
• a thermocompression-bonding step of heating the sheet and thermocompression-bonding the sheet to the one side of the wafer, after the contacting step.