Particle prevention method in chamber

A particle prevention method in chamber configured to remove particle in a reaction chamber, wherein a holder plate is disposed within an accommodating space of the reaction chamber;

• the method comprising:
• providing a shielding ring, wherein the shielding ring includes a first side wall, a second side wall, and a bottom, the second side wall is parallel to the first side wall, and the bottom being is connected to the first side wall and the second side wall to form an annular groove area;
• and the bottom is provided with at least one flow aperture, and an inner side of the second side wall defines an opening to receive the holder plate;
• connecting the first side wall to the reaction chamber with the first side wall extending toward an upper portion of an accommodating space of the reaction chamber;
• fixing a first deflector plate to the first side wall, wherein the first deflector plate extends obliquely toward the bottom, such that the first deflector plate is located above the at least one flow aperture of the bottom;
• and
• fixing a second deflector plate to the second side wall, wherein the second deflector plate is located above the first deflector plate, wherein the first deflector plate extends obliquely toward the bottom without contacting the bottom and the first side wall.