Vacuum processing apparatus

1. A vacuum processing apparatus having a vacuum processing chamber, a gas supply unit for supplying processing gas to the vacuum processing chamber, and a turbo-molecular pump for reducing pressure of the vacuum processing chamber, wherein the vacuum processing apparatus comprising a particle dispersion prevention unit disposed between the turbo-molecular pump and the vacuum processing chamber,

wherein the particle dispersion prevention unit includes a blade support ring, a plurality of blades provided on an outer circumference of the blade support ring, and an annular space formed downstream of the plural blades,

wherein a tilting direction of the blade of the particle dispersion prevention unit is opposite a tilting direction of a rotary blade of the turbo-molecular pump, and a gap between the blades forms a first exhaust route,

wherein the blade support ring includes a hole formed in a center, which forms a second exhaust route as a gas passage, and

wherein the annular space transfers the gas passing through the second exhaust route in a radial direction so as to be mixed with the gas passing through the first exhaust route to form a third exhaust route for guiding the mixed gas to the rotary blade of the turbo-molecular pump.

2. The vacuum processing apparatus according to claim 1 , wherein a relationship of Ha≧0.2×g is satisfied; where Ha denotes a height of the annular space and g denotes a radial length of the rotary blade of the turbo-molecular pump.

3. The vacuum processing apparatus according to claim 1 ,

wherein an inner diameter of the turbo-molecular pump is substantially equal to a diameter d of an inner wall of the particle dispersion prevention unit, and

a relationship of e≧0.25×d is satisfied; where e denotes a diameter of a hole formed in the center of the particle dispersion prevention unit.

4. The vacuum processing apparatus according to claim 1 , further comprising a tray provided to face the annular space of the particle dispersion prevention unit above a rotary shaft of the turbo-molecular pump for preventing the particle from dropping onto an upper surface of the rotary shaft.

5. The vacuum processing apparatus according to claim 4 , wherein a relationship of Ha≧0.1×g is satisfied; where g denotes a radial length of the rotary blade of the turbo-molecular pump and Ha denotes a distance between a lower end of the blade of the particle dispersion prevention unit and the tray.

6. The vacuum processing apparatus according to claim 1 , further comprising a particle terminator with a space for guiding the particle scattered by the turbo-molecular pump and a convex structure for deceleration by diffusely reflecting the particle in the particle terminator provided on an upper outer circumference of the turbo-molecular pump.

7. The vacuum processing apparatus according to claim 6 , wherein the particle terminator is formed at a position outside the annual space in a radial direction.

8. A vacuum processing apparatus having a vacuum processing chamber, and a particle dispersion prevention unit disposed in a space between a pressure adjusting valve in an exhaust system of the vacuum processing chamber and a turbo-molecular pump,

wherein the particle dispersion prevention unit includes a support ring with a hole formed in a center, a plurality of stationary blades which are tilted in a direction opposite a direction of a rotary blade of the turbo-molecular pump on an outer circumference of the ring member, and an annular space formed downstream of the plural stationary blades, and

wherein the annular space forms a third exhaust route which transfers gas passing through a second exhaust route via the hole of the support ring in a radial direction so as to be mixed with the gas passing through a first exhaust route via a gap between the stationary blades for guiding the mixed gas into the rotary blade of the turbo-molecular pump.

9. The vacuum processing apparatus according to claim 8 , wherein a relationship of Hb≧d is satisfied; where d denotes an inner diameter of the turbo-molecular pump, and Hb denotes a distance between a lower end of the blade of the particle dispersion prevention unit and an upper end of the rotary blade at an uppermost stage of the turbo-molecular pump.

10. The vacuum processing apparatus according to claim 9 , wherein relationships of e≧g+f and d≈f+2×g are satisfied; where e denotes a diameter of the center hole, g denotes a radial length of the rotary blade, and f denotes a diameter of a rotary shaft of the rotary blade.