Method for releasing stress of wafer in high-temperature heating stage

The invention discloses a method for releasing stress of a wafer in a high-temperature heating stage, which comprises the following steps of: S1, before the wafer is transferred to the high-temperature heating stage, lifting an ejector pin for supporting the wafer on a heating carrying stage in a cavity, transferring the wafer to the ejector pin by utilizing a manipulator, keeping the ejector pin in a lifting state, and carrying out thermal radiation heating on the wafer for a certain time t1; s2, the ejector pin falls down, and the wafer makes contact with the heating stage and is kept for a certain time t2; s3, introducing gas into the cavity to keep a certain cavity pressure P1 for a certain time t3; s4, gradually increasing the cavity pressure of the cavity; and meanwhile, after the cavity pressure is increased each time, keeping for a certain time t4 until the stress of the wafer is released in a high-temperature environment. Therefore, the high-temperature heating stage is adopted to indirectly and grad