Method of in-line temperature monitoring

摘要

A method of in-line temperature monitoring. At least two control wafers and a monitor wafer are provided. A sacrificial layer is formed on each control wafer and the monitor wafer. Ions are implanted under a predetermined condition in the sacrificial layers. Thermal processes are performed on the control wafers at a higher and the lower limit of a target temperature to enable ions to move partially from the sacrificial layer to the control wafers. The sacrificial layers on the control wafers are subsequently removed. The sheet resistance of the control wafers is measured to obtain a first and the second resistance value, which respectively correspond to the first and second temperatures. A wafer and a monitor wafer are provided. A thermal process is performed on the monitor wafer and the wafer at the target temperature. The sacrificial layer of the monitor wafer is removed, and the sheet resistance of the monitor wafer is subsequently measured. When the sheet resistance of the monitor wafer is between the first and the second sheet resistance, the temperature is controlled between the first and second temperature, that is, a tolerable temperature range of the target temperature.