A circular ion source for etching

Abstract

A circular ion source for etching includes a discharge arc chamber, a first magnetic field assembly is provided at the bottom of the discharge arc chamber, a second magnetic field assembly is provided on the periphery of the first magnetic field assembly, a third magnetic field assembly is provided on the periphery of the discharge arc chamber and a grid assembly is provided on the top, the first magnetic field assembly includes a magnetic column disk, a plurality of magnetic column holes are provided in the radial direction on the magnetic column disk, a first magnetic column is provided in the magnetic column hole, and a first magnetic ring is provided on the side of each circle of the first magnetic column close to the discharge arc chamber, the second magnetic field assembly includes a second magnetic ring, a third magnetic ring located on the periphery of the second magnetic ring, and a plurality of second magnetic columns arranged circumferentially between the second and third magnetic rings, the second magnetic columns are arranged radially, the third magnetic field assembly includes a fourth magnetic ring, a fifth magnetic ring located above the fourth magnetic ring, and a plurality of third magnetic columns arranged circumferentially between the fourth and fifth magnetic rings. The present invention is conducive to adjusting the magnetic field strength in the discharge arc chamber, thereby adjusting the etching uniformity within a large diameter range.

Description

Technical Field

[0001] The present invention relates to semiconductor processing equipment, in particular to a circular ion source for etching. Background Art

[0002] Conventional ion beam etching uses a circular ion source and uses low-energy parallel Ar + The ion beam bombards the substrate surface, sputtering out the portion of the substrate surface not covered by the mask, thereby achieving the purpose of selective etching. Ion beam etching is a purely physical etching process, and has the characteristics of high resolution and good steepness among various conventional etching methods.

[0003] With the increase in the size of etched substrates and the improvement in production capacity requirements, higher requirements are placed on the ion source beam diameter and large-scale etching uniformity. The beam diameter of traditional circular ion sources is relatively small, and it is difficult to ensure etching uniformity within a large diameter range. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a circular ion source for etching which has a simple structure and is conducive to adjusting the magnetic field strength in the discharge arc chamber, thereby adjusting the etching uniformity within a large diameter range.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A circular ion source for etching, comprising a cylindrical discharge arc chamber, a first magnetic field assembly being provided at the bottom of the discharge arc chamber, a second magnetic field assembly being provided on the outer periphery of the first magnetic field assembly, a third magnetic field assembly being provided on the outer periphery of the discharge arc chamber and a grid assembly being provided on the top, the first magnetic field assembly comprising a magnetic column disk, a plurality of magnetic column holes being provided radially on the magnetic column disk, a first magnetic column being provided in the magnetic column holes, and a first magnetic conductive ring being provided on a side of each circle of the first magnetic column close to the discharge arc chamber, the second magnetic field assembly comprising a second magnetic conductive ring, a third magnetic conductive ring being located on the outer periphery of the second magnetic conductive ring, and a plurality of second magnetic columns being arranged circumferentially between the second magnetic conductive ring and the third magnetic conductive ring, each of the second magnetic columns being arranged radially, the third magnetic field assembly comprising a fourth magnetic conductive ring, a fifth magnetic conductive ring being located above the fourth magnetic conductive ring, and a plurality of groups of third magnetic columns being arranged circumferentially between the fourth magnetic conductive ring and the fifth magnetic conductive ring.

[0007] As a further improvement of the above technical solution: the distance between two adjacent first magnetic columns in the same circle of first magnetic columns is a, the gap between two adjacent second magnetic columns is b, and the gap between two adjacent third magnetic columns is c, then a<b<c.

[0008] As a further improvement of the above technical solution: a plurality of filament electrodes are further provided at the bottom of the discharge arc chamber, and the plurality of filament electrodes are arranged between the first magnetic field assembly and the second magnetic field assembly along the circumferential direction, and a filament is installed on each filament electrode.

[0009] As a further improvement of the above technical solution: the grid assembly includes a screen grid mounting flange arranged on the discharge arc chamber, a screen grid arranged on the screen grid mounting flange, an acceleration grid arranged above the screen grid, and a ground grid arranged above the acceleration grid, the screen grid, the acceleration grid and the ground grid are fixedly connected by an insulating connector, and the insulating connector is provided with multiple grid holes that are evenly arranged around the center.

[0010] As a further improvement of the above technical solution: the acceleration grid and the ground grid are respectively equipped with wiring lugs, and the wiring lugs are insulated and installed on the screen grid mounting flange.

[0011] As a further improvement of the above technical solution: a water cooling jacket is further provided on the outer periphery of the discharge arc chamber.

[0012] Compared with the prior art, the advantages of the present invention are as follows: the circular ion source for etching disclosed by the present invention is provided with a first magnetic field component and a second magnetic field component at the bottom of the discharge arc chamber, a third magnetic field component is provided on the periphery of the discharge arc chamber, and a grid component is arranged on the top of the discharge arc chamber to ionize Ar. + Under the action of the magnetic field and the grid electric field, ions are drawn out from the grid holes to form an ion beam. Preferably, the number of the first magnetic columns in each circle of the magnetic column disk is adjusted from the bottom of the discharge arc chamber, so that the magnetic field strength in the discharge arc chamber can be effectively adjusted, thereby adjusting the uniformity of the extracted beam. It has been verified that when the extracted beam from the ion source covers an etching range with a diameter of 300 mm, the etching uniformity within the etching range with a diameter of 300 mm can still be adjusted and optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic cross-sectional structural diagram of a circular ion source used for etching according to the present invention.

[0014] Figure 2 It is a structural schematic diagram of the bottom of the discharge arc chamber in the present invention.

[0015] Figure 3 It is a schematic diagram of the three-dimensional structure of the magnetic field component in the present invention.

[0016] Figure 4 It is a schematic diagram of the main structure of the first magnetic field component in the present invention.

[0017] Figure 5 It is a schematic cross-sectional structural diagram of the first magnetic field component in the present invention.

[0018] Figure 6 It is a structural schematic diagram of the magnetic column disk in the present invention.

[0019] Figure 7 It is a structural schematic diagram of the first magnetic conductive ring in the present invention.

[0020] Figure 8 It is a structural schematic diagram of the grid assembly in the present invention.

[0021] The numbers in the figure represent: 1. discharge arc chamber; 2. first magnetic field assembly; 21. magnetic column disk; 22. magnetic column hole; 23. first magnetic column; 24. first magnetic conductive ring; 3. second magnetic field assembly; 31. second magnetic conductive ring; 32. third magnetic conductive ring; 33. second magnetic column; 4. third magnetic field assembly; 41. fourth magnetic conductive ring; 42. fifth magnetic conductive ring; 43. third magnetic column; 5. grid assembly; 51. screen grid mounting flange; 52. screen grid; 53. acceleration grid; 54. ground grid; 55. insulating connector; 56. grid mesh hole; 57. terminal lug; 6. filament electrode; 7. water cooling jacket; 8. anode ring. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Figures 1 to 8 An embodiment of a circular ion source for etching of the present invention is shown. The circular ion source for etching of this embodiment includes a cylindrical discharge arc chamber 1, a first magnetic field assembly 2 is provided at the bottom of the discharge arc chamber 1, a second magnetic field assembly 3 is provided on the periphery of the first magnetic field assembly 2, a third magnetic field assembly 4 is provided on the periphery of the discharge arc chamber 1 and a grid assembly 5 is provided on the top, the first magnetic field assembly 2 includes a magnetic column disk 21, a plurality of magnetic column holes 22 are provided radially on the magnetic column disk 21, a first magnetic column 23 is provided in the magnetic column hole 22, and each circle of the first magnetic column 23 is in close contact with the discharge arc A first magnetic ring 24 is provided on one side of chamber 1. The second magnetic field assembly 3 includes a second magnetic ring 31, a third magnetic ring 32 positioned outside the second magnetic ring 31, and multiple second magnetic pillars 33 circumferentially arranged between the second and third magnetic rings 31, 32. Each second magnetic pillar 33 is radially arranged. The third magnetic field assembly 4 includes a fourth magnetic ring 41, a fifth magnetic ring 42 positioned above the fourth magnetic ring 41, and multiple groups of third magnetic pillars 43 circumferentially arranged between the fourth and fifth magnetic rings 41, 42. Five circles of magnetic pillar holes 22 are provided, with multiple waist-shaped holes circumferentially defined between adjacent circles of magnetic pillar holes 22. Six groups of third magnetic pillars 43 are provided, each group containing five third magnetic pillars 43. In other embodiments, the number of magnetic field assemblies may be adjusted accordingly as the ion source diameter changes.

[0024] The circular ion source for etching is provided with a first magnetic field component 2 and a second magnetic field component 3 at the bottom of the discharge arc chamber 1, a third magnetic field component 4 is provided on the periphery of the discharge arc chamber 1, and a grid component 5 is arranged on the top of the discharge arc chamber 1 to ionize Ar. + Under the action of the magnetic field and the grid electric field, ions are extracted from the grid holes 56 to form an ion beam. Preferably, the number of the first magnetic pillars 23 in each circle of the magnetic pillar disk 21 is adjusted from the bottom of the discharge arc chamber 1 (the installation position of the first magnetic pillars 23 and the installation method of being arranged in the magnetic pillar holes 22 are more convenient to adjust than the second magnetic pillars 33 and the third magnetic pillars 43). The magnetic field strength in the discharge arc chamber 1 can be effectively adjusted, thereby adjusting the uniformity of the extracted beam. It has been verified that when the extracted beam from the ion source covers an etching range with a diameter of 300 mm, the etching uniformity within the etching range with a diameter of 300 mm can still be adjusted to optimize.

[0025] Furthermore, in this embodiment, the spacing between two adjacent first magnetic pillars 23 in the same circle of first magnetic pillars 23 is a, the gap between two adjacent second magnetic pillars 33 is b, and the gap between two adjacent third magnetic pillars 43 is c, then a<b<c, that is, the first magnetic pillars 23 in the first magnetic field assembly 2 are arranged the densest, the third magnetic pillars 43 in the third magnetic field assembly 4 are arranged the sparsest, and the second magnetic pillars 33 in the second magnetic field assembly 3 are centered, which is conducive to reducing the difficulty of adjusting the magnetic field intensity of the discharge arc chamber 1 and improving the adjustment efficiency.

[0026] Furthermore, in this embodiment, six filament electrodes 6 are provided at the bottom of the discharge arc chamber 1. The six filament electrodes 6 are arranged between the first magnetic field assembly 2 and the second magnetic field assembly 3 along the circumferential direction. A filament (not shown in the figure) is installed on each filament electrode 6. Each filament electrode 6 can be selectively connected in series to effectively adjust the ion beam distribution; when the filament reaches the end of its service life, it is only necessary to remove the filament electrode 6 and replace the filament, which is simple and convenient.

[0027] Furthermore, in this embodiment, the grid assembly 5 includes a screen grid mounting flange 51 disposed on the discharge arc chamber 1, a screen grid 52 disposed on the screen grid mounting flange 51, an acceleration grid 53 disposed above the screen grid 52, and a ground grid 54 disposed above the acceleration grid 53. The screen grid 52, the acceleration grid 53, and the ground grid 54 are fixedly connected by an insulating connector 55. The insulating connector 55 has multiple grid holes 56 arranged evenly around the center. Conventional ion source grid components each have a mounting flange. The grid assembly 5 of this embodiment has only one screen grid mounting flange 51. The screen grid 52 is disposed on the screen grid mounting flange 51. The screen grid 52, the acceleration grid 53, and the ground grid 54 are fixedly connected by the insulating connector 55. This simplifies the structure of the grid assembly 5. Furthermore, the multiple insulating connectors 55 are evenly arranged around the central grid hole 56, effectively preventing grid deformation and facilitating beam uniformity. The insulating connector 55 can be, for example, a ceramic insulating ring.

[0028] Furthermore, in this embodiment, the accelerating grid 53 and the grounding grid 54 are each equipped with a lug 57, which is insulated and mounted on the screen grid mounting flange 51. Each grid of the driven ion source grid assembly is equipped with a mounting flange, and power is directly connected to the corresponding mounting flange. In this embodiment, the grid assembly 5 is connected directly to the grid via the lug 57, with voltage access to the accelerating grid 53 and grounding of the grounding grid 54, respectively. This provides a simpler structure and more convenient connection.

[0029] As a preferred embodiment, a water cooling jacket 7 is further provided on the periphery of the discharge arc chamber 1. The water cooling jacket 7 wraps the discharge arc chamber 1 and other key components of the ion source, effectively absorbing the heat released during the ion source discharge process, and ensuring long-term stable operation of the ion source.

[0030] Although the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, utilize the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A circular ion source for etching, characterized in that: The invention comprises a cylindrical discharge arc chamber (1), wherein a first magnetic field assembly (2) is provided at the bottom of the discharge arc chamber (1), a second magnetic field assembly (3) is provided on the outer periphery of the first magnetic field assembly (2), a third magnetic field assembly (4) is provided on the outer periphery of the discharge arc chamber (1) and a grid assembly (5) is provided on the top, the first magnetic field assembly (2) comprises a magnetic column disk (21), a plurality of magnetic column holes (22) are provided on the magnetic column disk (21) in a radial direction, a first magnetic column (23) is provided in the magnetic column hole (22), and a first magnetic conductive ring (24) is provided on the upper side of each circle of the first magnetic column (23), and the second magnetic column (23) is provided on the upper side of each circle of the first magnetic column (23). The field assembly (3) comprises a second magnetic conductive ring (31), a third magnetic conductive ring (32) located on the periphery of the second magnetic conductive ring (31), and a plurality of second magnetic columns (33) arranged between the second magnetic conductive ring (31) and the third magnetic conductive ring (32) along the circumferential direction, wherein each of the second magnetic columns (33) is arranged radially; and the third magnetic field assembly (4) comprises a fourth magnetic conductive ring (41), a fifth magnetic conductive ring (42) located above the fourth magnetic conductive ring (41), and a plurality of groups of third magnetic columns (43) arranged between the fourth magnetic conductive ring (41) and the fifth magnetic conductive ring (42) along the circumferential direction.

2. The circular ion source for etching according to claim 1, characterized in that: The spacing between two adjacent first magnetic columns (23) in the same circle of first magnetic columns (23) is a, the spacing between two adjacent second magnetic columns (33) is b, and the spacing between two adjacent third magnetic columns (43) is c, then a<b<c.

3. The circular ion source for etching according to claim 1, characterized in that: A plurality of filament electrodes (6) are further provided at the bottom of the discharge arc chamber (1). The plurality of filament electrodes (6) are arranged between the first magnetic field component (2) and the second magnetic field component (3) along a circumferential direction, and a filament is mounted on each filament electrode (6).

4. The circular ion source for etching according to any one of claims 1 to 3, characterized in that: The grid assembly (5) comprises a screen grid mounting flange (51) provided on the discharge arc chamber (1), a screen grid (52) provided on the screen grid mounting flange (51), an acceleration grid (53) provided above the screen grid (52), and a ground grid (54) provided above the acceleration grid (53). The screen grid (52), the acceleration grid (53), and the ground grid (54) are fixedly connected via an insulating connector (55). The insulating connector (55) is provided with a plurality of grid holes (56) evenly arranged around a center.

5. The circular ion source for etching according to claim 4, characterized in that: The acceleration grid (53) and the ground grid (54) are respectively provided with a connecting piece (57), and the connecting piece (57) is insulated and mounted on the screen grid mounting flange (51).

6. The circular ion source for etching according to any one of claims 1 to 3, characterized in that: A water cooling jacket (7) is also provided on the outer periphery of the discharge arc chamber (1).

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