Filter for a plasma plume

Abstract

The invention relates to a filter for filtering particles from a plasma plume. The filter includes a housing with two pass-through openings arranged in the housing wall and forming a pass-through channel for passing at least part of the plasma plume through the housing, which pass-through channel extends from one side of the housing to an opposite side of the housing, at least one primary blade arranged at a distance from and rotatable around a rotation axis, which rotation axis is parallel and spaced apart from the center line of the pass-through channel, with the path of the at least one primary blade intersecting with the pass-through channel and with the at least one primary blade having a contact surface for contact with the plasma plume, which contact surface is facing in the direction of the rotation direction, and a drain channel connecting to a drain opening arranged in the housing wall. A line extending perpendicular from both the center line of the pass-through channel and a radial line extending from the rotation axis through the center line of the pass-through channel and through the path of the at least one primary blade, extends through the drain opening.

Claims

1. A filter for filtering particles from a plasma plume, which filter comprises: a housing with two pass-through openings arranged in a housing wall and forming a pass-through channel for passing at least part of the plasma plume through the housing, which pass-through channel extends from one side of the housing to an opposite side of the housing; at least one primary blade arranged at a distance from and rotatable around a rotation axis, which rotation axis is parallel and spaced apart from a center line of the pass-through channel, wherein a path of the at least one primary blade intersects with the pass-through channel and wherein the at least one primary blade has a contact surface for contact with the plasma plume, which contact surface is facing in a direction of a rotation direction; and a drain channel connecting to a drain opening arranged in the housing wall, wherein a line extending perpendicular from both the center line of the pass-through channel and a radial line extending from the rotation axis through the center line of the pass-through channel and through the path of the at least one primary blade, extends through the drain opening.

2. The filter according to claim 1, wherein a cord line of a radial cross-section of the contact surface makes an angle larger than 0° with the rotation axis.

3. The filter according to claim 1, wherein a cord line of an axial cross-section of the contact surface makes an angle larger than 0° with a radial line extending from the rotation axis and through an inner edge of the axial cross-section of the contact surface.

4. The filter according to claim 1, wherein the contact surface is a concave shaped surface facing in the direction of the rotation direction of the at least one primary blade.

5. The filter according to claim 1, wherein the rotation axis is a rotation axis of the at least one primary blade, further comprising a disc rotatably arranged in the housing, wherein a rotation axis of the disc coincides with the rotation axis of the at least one primary blade, wherein at least one pass-through opening is arranged in the disc at a distance from the rotation axis of the disc corresponding with the distance of the center line of the pass-through channel to the rotation axis of the at least one primary blade, and wherein the at least one primary blade is arranged on top of the disc adjacent to and trailing, when viewed in a rotation direction of the disc, the at least one pass-through opening in the disc.

6. The filter according to claim 5, wherein a cylindrical wall is arranged on the disc and concentrically with the rotation axis and wherein the at least one primary blade connects to the outside of the cylindrical wall.

7. The filter according to claim 1, further comprising a secondary blade arranged rotatable around the rotation axis.

8. The filter according to claim 7, wherein an angle between the longitudinal axis of the at least one primary blade and a radial line extending from the rotation axis to a proximal end of the at least one primary blade is smaller than an angle between the longitudinal axis of the secondary blade trailing the respective at least one primary blade and a radial line extending from the rotation axis to the proximal end of said secondary blade.

9. The filter according to claim 1, wherein a number of auxiliary blades is arranged at a distance from and rotatable around the rotation axis and which number of auxiliary blades is distributed along the path and at a distance from the at least one primary blades.

10. The filter according to claim 9, further comprising an auxiliary drain channel connecting to an auxiliary drain opening arranged in the housing wall, and pump means to generate a pressure difference between the rotation axis and the auxiliary drain channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features of the invention will be elucidated in conjunction with the accompanying drawings.

(2) FIG. 1 shows a schematic perspective view of an embodiment of a filter according to the invention arranged in a PLD device.

(3) FIG. 2 shows a cross-sectional view along the line II-II in FIG. 1.

(4) FIG. 3 shows a perspective view of the disc with blades of the filter according to FIG. 1.

(5) FIG. 4 shows top cross-sectional view of the filter according to the invention in a first state.

(6) FIG. 5 shows top cross-sectional view of the filter according to the invention in a second state.

(7) FIGS. 6A and 6B show an axial top view and a cross-sectional radial view of the primary blade with a concave surface as shown in FIG. 5 on enlarged scale.

DESCRIPTION OF THE INVENTION

(8) FIG. 1 shows a schematic view of an embodiment 1 of a filter according to the invention. The filter 1 has a housing 2 with a pass-through opening 3 at the top and a pass-through opening 4 at the bottom (see FIG. 2). The housing 2 is provided with a drain channel 5 and an auxiliary drain channel 6.

(9) A target material 7 is arranged above the pass-through opening 3 of the filter 1. If a laser beam 8 is pulsed onto the target material 7, a plasma plume 9 will be generated.

(10) This plasma plume 9 will enter the pass-through opening 3, where undesired particles are filtered, such that a filtered plasma plume 10 will exit the filter 1 through the pass-through opening 4. The filtered plasma plume 10 is then deposited onto a substrate 11.

(11) As shown in FIG. 2, a disc 12 is arranged rotatably in the housing 2 of the filter 1. On top of the disc a primary blade with a concave surface 13 is provided adjacent to a pass-through opening 14, which allows passage of a plasma plume 9, when the pass-through opening 14 is aligned with the pass-through openings 3, 4 in the housing 2 and forming a pass-through channel with a center line 15.

(12) When the plasma plume 9 passes through the formed pass-through channel, the primary blade with concave surface 13 with swipe through the last part of the plasma plume 9 and will bounce undesired particles in the direction D to the drain opening and the connected drain channel 5.

(13) FIG. 3 shows a perspective view of the disc 12 rotatably arranged around the rotation axis 16 in the housing 2 of the filter 1.

(14) The disc 12 is provided with two oppositely arranged pass-through openings 14, which are each trailed by a primary blade 13 having a concave surface. Just behind each primary blade 13, a secondary blade 17 is arranged to bounce off particles towards the drain channel 5, which particles are too slow to be hit by the primary blade 13. Furthermore, a number of auxiliary blades 18 are arranged on top of the disc 12.

(15) A cylindrical wall 19 is arranged radially inside of the primary blades 13, secondary blades 17 and auxiliary blades 18 to provide together with the housing 2 a more confined space for the undesired particles of the plasma plume 9.

(16) FIG. 4 shows a cross-sectional top view of the filter 1 of the invention.

(17) The housing 2 has a drain opening 20, on which the drain channel 5 is connected. This drain opening 20 is arranged on a line 21 extending perpendicular from both the center line 15 of the pass-through channel and a radial line 22 extending from the rotation axis 16 through the center line 15 of the pass-through channel.

(18) The housing 2 has also an auxiliary drain opening 23, on which the auxiliary drain channel 6 is connected. This drain opening 23 is arranged on a line 24 extending perpendicular from both the center line 15 of the pass-through channel and a radial line 22 extending from the rotation axis 16 through the center line 15 of the pass-through channel.

(19) FIG. 5 shows again the cross-sectional top view of the filter 1 of the invention. From this FIG. 5 it is clear that the radial line 25 extending from the rotation axis 16 to the proximal end of the primary blade 13 makes an angle α.sub.1 with the longitudinal axis 26 of the primary blade.

(20) The radial line 27 extending from the rotation axis 16 to the proximal end of the secondary blade 17 makes an angle α.sub.2 with the longitudinal axis 28 of the secondary blade 17.

(21) The radial line 29 extending from the rotation axis 16 to the proximal end of the auxiliary blade 18 makes an angle α.sub.3 with the longitudinal axis 50 of the auxiliary blade 18.

(22) As already described above, the primary blade 13 has a concave surface which focuses the particles from the plasma plume 9 hit by the primary blade 13 in a bundle 51 towards the drain opening 20 and the drain channel 5.

(23) Furthermore, a pressure difference is generated between the center of the filter 1, around the rotation axis 16 and the auxiliary drain channel 6, such that an airflow L is generated which flows from the center towards the outside of the housing 2 in order to maintain pressure within the housing.

(24) FIGS. 6A and 6B show an axial top view and a cross-sectional radial view of the primary blade with a concave surface 13 as shown in FIG. 5 on enlarged scale.

(25) The concave surface 13 is curved from the bottom edge 30 towards the top edge 31 of the concave surface 13 and also in radial direction.

(26) The cord line 32 of the bottom edge 30 makes an angle α.sub.1 with the radial line 33, which intersects with the most inner edge of the cord line 32. The cord line 35 of the top edge 31 makes an angle β.sub.2 with the radial line 34, which intersects with the most inner edge of the cord line 32.

(27) Both angles α.sub.1 and β.sub.2 are larger than 0° and preferably larger than 15°.

(28) FIG. 6B shows a cross-sectional radial view of the concave surface 13. The cord line 36 makes an angle β.sub.3 with the rotation axis 16. Also this angle β.sub.3 is larger than 0° and preferably larger than 15°.