Filament and cathode assembly and ion source for ion implanter comprising same

Abstract

The utility model discloses a filament and cathode assembly and an ion source for an ion implanter comprising the same, a filament is arranged in a cathode, the cathode comprises a main body, the main body forms a cylindrical structure with an open end, and the thickness of the bottom wall of the main body accounts for 9.22 / 28 to 9.22 / 27 and 9.22 / 27 to 10.42 / 27 of the length of the main body; the distance between the lamp filament and the inner surface of the bottom wall accounts for 1 / 17.78 to 0.6 / 17.58 of the depth of the main body. According to the lamp filament and cathode assembly, the distance between the lamp filament and the inner surface of the bottom wall of the cathode and the ratio of the wall thickness of the bottom wall to the total length of the cathode are reasonably set, so that the time for thinning and breakdown of the cathode is prolonged, the time for effectively protecting the lamp filament can be prolonged, the service life of the lamp filament is prolonged, and the service life of the lamp filament is prolonged. And the output and the utilization rate of the ion implanter are improved.

Description

Technical Field

[0001] The utility model relates to the field of semiconductor equipment, and particularly relates to a filament and a cathode assembly, and an ion source for an ion implanter including the same. Background Art

[0002] The main application of an ion implanter in semiconductors is to dope atoms of different source species into a silicon substrate. N-type and P-type elements will be ionized and implanted onto the wafer surface through acceleration / deceleration / screening during the implantation process. One of the core components of an ion implanter is an ion source, and its main function is to ionize gas molecules.

[0003] The working principle of the ion source mainly includes heating a filament. After the filament is heated, filament thermoelectrons are generated. These thermoelectrons then heat the cathode. After the cathode is heated, cathode electrons are generated, and the cathode electrons are used to initiate an arc. As the cathode is consumed and its surface is thinned and broken through, the contact between the filament and the plasma will cause the filament to break quickly. After the filament breaks, replacement and maintenance are required, which affects the output and utilization rate of the ion implanter. Therefore, improving the cathode is crucial for protecting the filament, extending the life of the ion source, and the output and utilization rate of the ion implanter. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a filament and a cathode assembly, and an ion source for an ion implanter including the same, which can effectively protect the filament, extend the service life of the filament, and further extend the life of the ion source, and improve the output and utilization rate of the ion implanter.

[0005] To solve the above technical problem, the first aspect of the utility model is to provide a filament and a cathode assembly. The filament is placed inside the cathode. The cathode includes a main body, and the main body is formed into a cylindrical structure with an open end. The thickness of the bottom wall of the main body accounts for 9.22 / 28 to 9.22 / 27, and 9.22 / 27 to 10.42 / 27 of the length of the main body;

[0006] The distance between the filament and the inner surface of the bottom wall accounts for 1 / 17.78 to 0.6 / 17.58 of the depth of the main body.

[0007] Preferably, the thickness of the bottom wall is 9.22 - 10.42 mm;

[0008] The distance between the outer surface of the bottom wall and the open end face of the main body is 27 - 28 mm;

[0009] The distance between the inner surface of the bottom wall and the open end face of the main body is 17.58 - 17.78 mm;

[0010] The distance between the filament and the inner surface of the main body is 0.6 - 1.0 mm.

[0011] Preferably, the thickness of the bottom wall is 9.22 - 10.22 mm;

[0012] The distance between the outer surface of the bottom wall and the open end face of the main body is 27 - 28 mm;

[0013] The distance between the inner surface of the bottom wall and the open end face of the main body is 17.78 mm;

[0014] The distance between the filament and the inner surface of the main body is 0.8 - 1.0 mm.

[0015] Preferably, the thickness of the bottom wall is 9.22 - 9.42 mm;

[0016] The distance between the outer surface of the bottom wall and the open end face of the main body is 27 mm;

[0017] The distance between the inner surface of the bottom wall and the open end face of the main body is 17.58 - 17.78 mm;

[0018] The distance between the filament and the inner surface of the main body is 0.6 - 1.0 mm. <X

[0019] Preferably, the thickness of the bottom wall is 10.22;

[0020] The distance between the outer surface of the bottom wall and the open end face of the main body is 28 mm;

[0021] The distance between the inner surface of the bottom wall and the open end face of the main body is 17.78 mm;

[0022] The distance between the filament and the inner surface of the main body is 0.8 - 1.0 mm.

[0023] Preferably, a cathode cap connecting portion is formed circumferentially on the outer wall of the end portion of the main body close to the opening, and the outer diameter of the cathode cap connecting portion is larger than the outer diameter of the main body.

[0024] To solve the above technical problems, the second aspect of the present utility model is to provide an ion source for an ion implantation machine including the aforementioned filament and cathode assembly.

[0025] Preferably, the cathode cap connecting portion is connected with a cathode cap, and there is a gap between the inner wall of the cathode cap and the outer wall of the cathode.

[0026] Preferably, the cathode cap and the cathode cap connecting portion are connected by a thread.

[0027] The present utility model provides a filament and a cathode assembly, and reasonably sets the distance between the filament and the inner surface of the bottom wall of the cathode, as well as the proportion of the wall thickness of the bottom wall in the total length of the cathode, so as to prolong the time for the cathode to be thinned and broken down, thereby effectively prolonging the time for protecting the filament, which is beneficial to prolonging the service life of the filament and improving the output and utilization rate of the ion implanter. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the present utility model, the following briefly introduces the drawings required for the present utility model. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 is a schematic diagram of an embodiment of the filament and cathode assembly of the present utility model;

[0030] Figure 2 is a schematic diagram of an embodiment of the filament, cathode and cathode cap assembly of the ion source for ion implantation of the present utility model;

[0031] In the figure, 1 - filament; 2 - cathode; 21 - main body; 22 - bottom wall; 23 - cathode cap connection part; 24 - inner surface of the bottom wall; 25 - outer surface of the bottom wall; 3 - cathode cap. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the present utility model with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present utility model belong to the scope of protection of the present utility model.

[0033] Embodiment

[0034] Refer to Figure 1 , which shows a filament and cathode assembly. The filament is placed inside the cathode. The filament can be fixed with a filament clip, for example. This is prior art and will not be elaborated here. Among them, the cathode includes a main body, and the main body is formed into a cylindrical structure with an open end. The thickness of the bottom wall of the main body accounts for 9.22 / 28 to 9.22 / 27, and 9.22 / 27 to 10.42 / 27 of the length of the main body. The distance between the filament and the inner surface of the bottom wall accounts for 1 / 17.78 to 0.6 / 17.58 of the depth of the main body. It can be understood that in the embodiments of the present utility model, the length of the main body refers to the distance between the outer surface of the bottom wall and the open end face of the main body. The depth of the main body refers to the distance between the inner surface of the main body and the open end face of the main body.

[0035] In a specific embodiment, the thickness of the bottom wall is 9.22 - 10.42 mm; the distance between the outer surface of the bottom wall and the open end face of the main body is 27 - 28 mm; the distance between the inner surface of the bottom wall and the open end face of the main body is 17.58 - 17.78 mm.

[0036] In a specific embodiment, the thickness of the bottom wall is 9.22 - 10.22 mm; the distance between the outer surface of the bottom wall and the open end face of the main body is 27 - 28 mm; the distance between the inner surface of the bottom wall and the open end face of the main body is 17.78 mm.

[0037] In a specific embodiment, the thickness of the bottom wall is 9.22 - 9.42 mm; the distance between the outer surface of the bottom wall and the open end face of the main body is 27 mm; the distance between the inner surface of the bottom wall and the open end face of the main body is 17.58 - 17.78 mm.

[0038] In a specific embodiment, the thickness of the bottom wall is 10.22; the distance between the outer surface of the bottom wall and the open end face of the main body is 28 mm; the distance between the inner surface of the bottom wall and the open end face of the main body is 17.78 mm.

[0039] In a specific embodiment, a cathode cap connection part is formed along the circumferential direction on the outer wall of the end of the main body close to the opening, and the outer diameter of the cathode cap connection part is greater than the outer diameter of the main body.

[0040] Reference Figure 2 , shows the component structure of the filament, cathode and cathode cap of an ion source for an ion implanter, where the filament and cathode assembly adopt the filament and cathode assembly in the above embodiment; the cathode cap is connected to the cathode cap connection part by screw connection. Since the outer diameter of the cathode cap connection part is greater than the outer diameter of the main body, after connection, there is a gap between the inner wall of the cathode cap and the outer wall of the main body. It can be understood that the outer diameter of the main body here refers to the outer diameter of the part of the main body where the cathode cap connection part is not formed. The function of the cathode cap is to block the circumferential diffusion and overflow of electrons that may be generated on the side wall of the cathode, and ensure that the electrons generated by the cathode (mainly the bottom wall) move axially. The component structure of the filament, cathode and cathode cap in this specific embodiment can be directly applied to the ion source for an ion implanter. [[ID=…]]

[0041] Test Example

[0042] 1. Test Conditions

[0043] Doping Gas: ARS

[0044] Gas Flow Rate: 0.8 ccm

[0045] Beam Current: 100 ua

[0046] 2. Test method: Use the cathode of this embodiment as the experimental group, the cathode of the prior art (provided by the manufacturer) as the control group, and the cathode whose model does not fall within the protection scope of the present invention as the comparison group. Record the service life. The test results are shown in Table 1:

[0047]

[0048]

[0049] As can be seen from Table 1, increasing the thickness of the cathode bottom wall within the range of 9.22 - 10.42 mm is beneficial to extending the service life of the cathode; when the thickness of the cathode bottom wall increases by thickening the inner surface of the bottom wall towards the filament direction, and the increased thickness is within 0.2 mm, it is beneficial to extending the service life of the cathode. When the thickening exceeds 0.2 mm, the life of the cathode will be shorter than that of the prior art. This may be because the inner surface of the cathode bottom wall is too close to the filament, affecting the service life of the filament; when the thickness of the cathode bottom wall increases by thickening the outer surface of the bottom wall away from the filament direction, and the increased thickness is within 1 mm, it is beneficial to extending the service life of the cathode. When the thickening exceeds 1 mm, the life of the cathode will be shorter than that of the prior art. This may be because the distance between the outer surface of the bottom wall and the filament is too large, affecting the ionization efficiency, thereby increasing the loss of the filament and shortening the life of the filament.

[0050] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A filament and cathode assembly, wherein the filament is disposed within the cathode, characterized in that, The cathode includes a main body which is formed into a cylindrical structure with an open end, and the thickness of the bottom wall of the main body accounts for 9.22 / 28 to 9.22 / 27, as well as 9.22 / 27 to 10.42 / 27 of the length of the main body; The distance between the filament and the inner surface of the bottom wall accounts for 1 / 17.78 to 0.6 / 17.58 of the depth of the main body.

2. The filament and cathode assembly according to claim 1, characterized in that, The thickness of the bottom wall is 9.22 - 10.42 mm; The distance between the outer surface of the bottom wall and the open end face of the main body is 27 - 28 mm; The distance between the inner surface of the bottom wall and the open end face of the main body is 17.58 - 17.78 mm; The distance between the filament and the inner surface of the main body is 0.6 - 1.0 mm.

3. The filament and cathode assembly according to claim 1, characterized in that, The thickness of the bottom wall is 9.22 - 10.22 mm; The distance between the outer surface of the bottom wall and the open end face of the main body is 27 - 28 mm; The distance between the inner surface of the bottom wall and the open end face of the main body is 17.78 mm; The distance between the filament and the inner surface of the main body is 0.8 - 1.0 mm.

4. The filament and cathode assembly according to claim 1, characterized in that, The thickness of the bottom wall is 9.22 - 9.42 mm; The distance between the outer surface of the bottom wall and the open end face of the main body is 27 mm; The distance between the inner surface of the bottom wall and the open end face of the main body is 17.58 - 17.78 mm; The distance between the filament and the inner surface of the main body is 0.6 - 1.0 mm.

5. The filament and cathode assembly according to claim 1, characterized in that, The thickness of the bottom wall is 10.22; The distance between the outer surface of the bottom wall and the open end face of the main body is 28 mm; The distance between the inner surface of the bottom wall and the open end face of the main body is 17.78 mm; The distance between the filament and the inner surface of the main body is 0.8 - 1.0 mm.

6. The filament and cathode assembly according to claim 1, wherein, An outer wall of an end of the main body near the open end is circumferentially formed with a cathode cap connection portion, and an outer diameter of the cathode cap connection portion is greater than an outer diameter of the main body.

7. An ion source for an ion implanter including the filament and cathode assembly according to any one of claims 1 - 6.

8. The ion source for an ion implanter according to claim 7, wherein, The cathode cap connection portion is connected with a cathode cap, and there is a gap between an inner wall of the cathode cap and an outer wall of the cathode.

9. The ion source for an ion implanter according to claim 8, wherein, The cathode cap and the cathode cap connection portion are connected by a thread.

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