Abstract: Magnetic tunnel junctions (MTJ) represent a key component of magnetoresistive random access memory (MRAM). The magnetic amorphous materials utilized in the fabrication of MTJ necessitate annealing treatment, which facilitates the crystallization of MgO along the (001) direction. This enhances the spin filtering effect and improves the breakdown resistance of the MgO barrier layer. Furnace processing is among the most prevalent techniques in integrated circuit manufacturing, allowing for the simultaneous heat treatment of multiple wafers, thereby substantially increasing production capacity. Nevertheless, repeated temperature fluctuations during the annealing process can lead to the formation of particles within the chamber, which may deposit onto the wafers, resulting in defects, short circuits, and reduced yield. Furthermore, moisture, oxygen, and other impurity gases introduced during equipment maintenance or the heat treatment of wafers containing moisture can influence grain size at high temperatures and generate oxides, causing magnetic damage and reducing tunnel magnetoresistance R_TM and coercive force H_C. This study proposes a high-temperature pretreatment process within furnace tube technology, which promotes the accelerated detachment of defective particles or their enhanced adsorption to the chamber, thereby mitigating chamber contamination. Additionally, high-temperature pretreatment facilitates the removal of impurity gases such as moisture from the chamber, ensuring a stable internal environment and maintaining the performance and yield of MRAM products.