JP4277784B2 - Ion source equipment - Google Patents

Description

  The present invention relates to an ion source apparatus used for an ion implantation apparatus or the like, and more specifically to improvement of a structure around an extraction electrode system.

  A conventional example of this type of ion source apparatus is shown in FIG. Note that an ion source device having a similar structure is described in Patent Document 1.

  This ion source device includes a plasma generation unit 4 that generates plasma 7 in an ion source chamber 2 that is a vacuum container evacuated to a vacuum, and an electric field from the plasma 7 in the plasma generation unit 4 through an ion extraction hole 6. The extraction electrode system 10 for extracting the ion beam 8 by the action of the above is arranged.

  The plasma generation unit 4 generates plasma 7 by ionizing gas (including vapor) introduced into the plasma generation container 5 by discharge, and is described in, for example, Patent Document 1 The same as that of Bernus type. However, other types, such as the well-known Freeman type and high frequency discharge type, may be used.

  The extraction electrode system 10 is provided in the vicinity of the downstream side of the plasma generation unit 4 (downstream side in the traveling direction of the ion beam 8; the same applies hereinafter), and a high voltage (for example, a negative high voltage of about −2 kV) is applied. A high potential electrode 12 and a ground electrode 14 having a ground potential provided near the downstream side of the high potential electrode 12 are provided. Each of the electrodes 12 and 14 has ion extraction holes 13 and 15 through which the ion beam 8 passes. The ion extraction holes 13 and 15 have a shape corresponding to the ion extraction hole 6, for example, an elongated rectangular shape (also referred to as a slit shape; see FIG. 2) in the front and back direction of the paper surface of FIG. The shape of the ion extraction holes 6, 13, and 15 is not limited to this.

  The high potential electrode 12 is supported from the ground electrode 14 by a plurality of (for example, 3 to 4) insulators 16. The high voltage is applied to the high potential electrode 12 from the outside of the ion source chamber 2 via a feedthrough 24 and a wiring 30 attached to the ion source chamber 2 on the side thereof. The feedthrough 24 has an insulator 28 and a conductor 26 passing therethrough. The high-potential electrode 12 is also referred to as a suppression electrode because a negative high voltage is normally applied to suppress the backflow of electrons from the downstream side.

  The extraction electrode system 10 is supported at a predetermined position in the ion source chamber 2 using an electrode system support shaft 18 coupled to the ground electrode 14. Furthermore, this ion source device has an electrode driving device 20 that drives the extraction electrode system 10 in the gap direction indicated by the arrow A, the lateral direction indicated by the arrow B, and the rotation direction indicated by the arrow C via the electrode system support shaft 18. is doing. A portion where the electrode system support shaft 18 penetrates the ion source chamber 2 is vacuum-sealed by a bellows 22.

JP 2001-202896 (paragraphs 0018-0024, FIG. 1)

  The ion source device has the following problems.

(1) The insulation degradation of the surface 29 inside the ion source chamber 2 of the feedthrough 24 is fast. As a result, the apparatus must be stopped and the surface 29 must be cleaned frequently, reducing the operating rate of the apparatus.
This is because the feedthrough 24 is disposed on the side of the high potential electrode 12 in order to minimize the length of the wiring 30, and each ion extraction hole 6, 13 of the plasma generation unit 4 and the extraction electrode system 10. 15, and the surface 29 of the feedthrough 24 can be seen through the ion extraction holes 6, 13, 15, so that gas leaked from the ion extraction holes 6 of the plasma generation unit 4 This is because contaminants generated when the peripheral portion of the ion beam 8 collides with the electrodes 12 and 14 reach the surface 29 of the feedthrough 24 and easily adhere thereto.

(2) The workability of connecting the wiring 30 that electrically connects the feedthrough 24 and the high potential electrode 12 is poor.
This is because the space in the ion source chamber 2 is very narrow (if it is widened, the evacuation capacity of the ion source chamber 2 is increased and the vacuum pump capacity is increased), and the wiring 30 is used to prevent discharge. This is because the work efficiency is poor because the wiring must be wired at the shortest distance.

(3) The insulation deterioration of each insulator 16 of the extraction electrode system 10 is fast. As a result, the operating rate of the apparatus decreases for the same reason as in (1) above.
This is because the contaminants generated as described in (1) above easily reach and adhere to the surface of each insulator 16 located in the immediate vicinity of the generation site. For this, for example, as in the example shown in FIG. 4, there is an idea that each insulator 16 is combined with three insulators 32 to 34 to adopt a labyrinth structure. Plasma generated by leakage from the ion extraction hole 6 of the generation unit 4 or collision of the peripheral part of the ion beam 8 with the electrodes 12 and 14 spreads like a mist and enters the maze structure. Even if there is an effect of delaying the insulation deterioration of the insulators 16 somewhat, it is not a fundamental solution, and the insulation deterioration of each insulator 16 is still fast.

  Therefore, the present invention provides an ion source device that suppresses the deterioration of insulation of the system that supplies a high voltage to the high potential electrode of the extraction electrode system and increases the operating rate of the device, and eliminates the poor workability of wiring to the high potential electrode. The main purpose is to provide

  The ion source device according to the present invention penetrates the ion source chamber, and has a grounding potential electrode system support shaft having a support rod hole penetrating in the axial direction therein, and the electrode system support. A vacuum sealing means for vacuum-sealing between the shaft and the ion source chamber, and a hole for a support rod of the electrode system support shaft, with a space between the electrode system support shaft and passing therethrough; A high-potential support rod to which a high voltage is applied in the vicinity of an end portion outside the ion source chamber, and a hole for the support rod near the end portion outside the ion source chamber of the electrode system support shaft, An insulator provided between the electrode system support shaft and the high potential support rod to electrically insulate the two and support the high potential support rod; and the insulator, the electrode system support shaft and the high potential support Vacuum seal between bars And a first support that is coupled to an end of the high potential support rod inside the ion source chamber and supports the high potential electrode and electrically connects the high potential electrode to the high potential support rod. A body and an end of the electrode system support shaft inside the ion source chamber, and supports the ground electrode and electrically connects the ground electrode to the electrode system support shaft, The high-potential electrode, the first support, and the high-potential support rod are provided with a second support that is electrically insulated by a space without an insulator.

  According to the above ion source device, the high potential electrode is supported at a predetermined position in the ion source chamber by the high potential support rod and the first support, and the high potential electrode is passed from outside the ion source chamber via these. A high voltage can be applied.

  The ground electrode is supported at a predetermined position in the ion source chamber at the downstream side of the high potential electrode by the electrode system support shaft and the second support, and the ground electrode is set to the ground potential via these. be able to.

  The electrode system support shaft and the high potential support rod are electrically insulated by the insulator and vacuum sealed by the packing. The second support, the high-potential electrode, the first support, and the high-potential support rod are electrically insulated (that is, spatially insulated) by a space without using an insulator.

  Instead of providing the second support, the ground electrode is coupled to an end of the electrode system support shaft inside the ion source chamber, and the ground electrode, the high potential electrode, the first support, and the The space between the high-potential support rod and the high-potential support rod may be electrically insulated by an intervening space.

  The support rod hole is preferably provided on the downstream side of a position where the second support body or the ground electrode is coupled to the electrode system support shaft.

  The insulator protrudes from the insulator toward the inside of the ion source chamber. The insulator surrounds the high-potential support bar with a space, and opens a space between the electrode system support shaft and the insulator. It is preferable to have a cylindrical insulator.

  According to the first and second aspects of the present invention, the insulator that electrically insulates the electrode system support shaft from the high potential support rod is provided in the vicinity of the end of the electrode system support shaft outside the ion source chamber. Gas that leaks from the ion extraction hole of the plasma generation unit because it is far from each ion extraction hole of the plasma generation unit and extraction electrode system, and the insulator cannot be directly seen from each ion extraction hole. Contaminants due to plasma and plasma, and contaminants generated when the periphery of the ion beam collides with the high potential electrode or the ground electrode are unlikely to reach the insulator. Therefore, since the insulator is not very dirty and is not easily deteriorated in insulation, the frequency of cleaning can be greatly reduced as compared with the prior art, and the operating rate of the apparatus is greatly improved.

  In addition, an insulator is provided between the second support (in the case of claim 1) or the ground electrode (in the case of claim 2) for supporting the ground electrode and the high potential electrode, the first support and the high potential support rod. Therefore, there is no problem that the contaminants adhere to the insulator of the extraction electrode system and cause insulation deterioration. Therefore, for this reason, the operating rate of the apparatus is greatly improved.

  Furthermore, the high potential electrode is supported by the high potential support rod and the first support, and a high voltage can be applied to the high potential electrode from outside the ion source chamber via the high potential support rod and the first support. Since wiring for applying a high voltage to the electrode is unnecessary, it is possible to eliminate the poor workability of wiring to the high potential electrode, which the conventional technology has.

  According to the third aspect of the present invention, since the contaminants can be prevented from entering the hole for the support bar by the second support and / or the ground electrode, the contamination of the insulator can be more effectively prevented. There is a further effect that it can be suppressed.

  According to invention of Claim 4, since the creeping insulation distance of the said insulator becomes long with a cylindrical insulator, there exists the further effect that the insulation degradation of the said insulator can be suppressed smaller.

  FIG. 1 is a schematic sectional view showing an embodiment of an ion source device according to the present invention. FIG. 2 is a schematic front view seen in the direction of arrow DD in FIG. Portions that are the same as or correspond to those in the conventional example shown in FIG. 3 are given the same reference numerals, and differences from the conventional example will be mainly described below.

  This ion source device has a metal electrode system support shaft 50 penetrating through the hole 3 of the ion source chamber 2. The electrode system support shaft 50 has a support rod hole 52 penetrating in the axial direction of the electrode system support shaft 50 therein. The support rod hole 52 communicates with the ion source chamber 2 and is in a vacuum atmosphere.

  As in this embodiment, the support rod hole 52 is located downstream of a position where a second support 46 described later is coupled to the electrode system support shaft 50 (as described above, downstream in the traveling direction of the ion beam 8). Side). Moreover, it is preferable to provide a coolant channel 64 for cooling the ground electrode 14 and the like by flowing a coolant 66 such as cooling water, for example, in the electrode system support shaft 50 as in this embodiment.

  Between the electrode system support shaft 50 and the ion source chamber 2, vacuum sealing means is provided for vacuum-sealing between the two. More specifically, in this embodiment, there is a movable flange 68 for driving the electrode system support shaft 50 in the directions of the arrows A and B by an electrode driving device (not shown; refer to the electrode driving device 20 in FIG. 3). In order to perform vacuum sealing while allowing this drive, the movable flange 68 and the ion source chamber 2 are vacuum sealed by a bellows 72. Vacuum is provided between the flange 71 for attaching the bellows 72 to the ion source chamber 2 and the ion source chamber 2 and between the movable flange 68 and the electrode system support shaft 50 by packing (for example, O-rings) 74 and 76, respectively. It is sealed. Therefore, the bellows 72 constitutes the vacuum sealing means. Strictly speaking, the bellows 72 and the packings 74 and 76 constitute the vacuum sealing means. When the extraction electrode system 10 is not mechanically driven, vacuum sealing means other than the bellows 72 may be used.

  In this embodiment, since the electrode system support shaft 50 is rotated in the direction of the arrow C about the center axis of the electrode system support shaft 50 by the electrode driving device, the movable flange 68, the electrode system support shaft 50, Between them, a bearing 70 is provided.

  However, although it is preferable to drive the electrode system support shaft 50 as indicated by the arrows A, B and C, it is not essential to the present invention.

  A metal-made high-potential support rod 54 passes through a space between the support rod hole 52 of the electrode system support shaft 50 and the electrode system support shaft 50. A high voltage is applied, for example, from a DC high-voltage power supply 78 near the end of the high potential support rod 54 outside the ion source chamber 2. This high voltage is, for example, a negative high voltage of about −1 kV to −5 kV, more specifically about −2 kV.

  In the support rod hole 52 in the vicinity of the end of the electrode system support shaft 50 outside the ion source chamber 2, the electrode system support shaft 50 and the high potential support rod 54 are electrically insulated from each other. An insulator 56 for supporting the high potential support bar 54 is provided. The insulator 56 is made of, for example, insulating ceramics. Packing (for example, O-rings) 60 and 62 for vacuum-sealing between the insulator 56 and the electrode system support shaft 50 and the high potential support rod 54 are provided. Therefore, the support rod hole 52 is sealed from the atmosphere outside the ion source chamber 2 by the packings 60 and 62.

  As in this embodiment, the insulator 56 preferably has a cylindrical insulator 58 that protrudes from the insulator 56 toward the inside of the ion source chamber 2. The cylindrical insulator 58 surrounds the high-potential support rod 54 with a space, and also opens a space with the electrode system support shaft 50. The cylindrical insulator 58 may be integrated with the insulator 56 or may be separate.

  A high potential electrode 12 is supported at a predetermined position in the ion source chamber 2 (more specifically, in the vicinity of the downstream side of the plasma generation unit 4) at the end of the high potential support rod 54 inside the ion source chamber 2. In addition, a metal first support 40 that electrically connects the high potential electrode 12 to the high potential support rod 54 is coupled. In this embodiment, the first support body 40 is made of metal and has a plate-like (more specifically, disc-like) support plate 42 and a plurality of (four in this example) metal protruding from the upstream side. And a support post 44 made of steel.

  In this embodiment, the ground electrode 14 is provided with a cylindrical (in this example, a rectangular cylindrical) electrode 36 protruding downstream from the cylindrical electrode 36, and the cylindrical electrode 36 is a hole provided in the support plate 42. 43 passes through the support plate 42 with a space. The cylindrical electrode 36 has an effect of suppressing the divergence of the ion beam 8 and contamination of other portions, and is usually provided but is not essential. The total of the cylindrical electrode 36 and the ground electrode 14 may be referred to as a ground electrode.

  At the end inside the ion source chamber 2 of the electrode system support shaft 50, the ground electrode 14 is supported at a predetermined position in the ion source chamber 2 (more specifically, near the downstream side of the high potential electrode 12), and A metal second support 46 is connected to electrically connect the ground electrode 14 to the electrode system support shaft 50. The second support 46 has holes 47 through which the respective struts 44 pass through with a space between the second support 46 and the second support 46. A space is also provided between the second support 46, the high potential electrode 12, the first support 40, and the high potential support rod 54. Therefore, the second support 46 and the high-potential electrode 12, the first support 40, and the high-potential support rod 54 are electrically insulated by a space without using an insulator (without using an insulator). Space insulation). The ground electrode 14 and the cylindrical electrode 36, and the high potential electrode 12 and the first support 40 are also electrically insulated by a space without an insulator.

  According to the ion source device, the insulator 56 that electrically insulates between the electrode system support shaft 50 and the high potential support rod 54 is provided in the vicinity of the end of the electrode system support shaft 50 outside the ion source chamber 2. In addition, the insulator 56 is far away from the ion extraction holes 6, 13, and 15 of the plasma generation unit 4 and the extraction electrode system 10, and the insulator 56 cannot be directly seen through the ion extraction holes 6, 13, and 15. The contaminants caused by gas and plasma leaking from the ion extraction hole 6 of the plasma generation unit 4 and the contaminants generated when the peripheral part of the ion beam 8 collides with the high-potential electrode 12 and the ground electrode 14 are insulated from the insulation. It is difficult to reach the body 56. Accordingly, since the insulator 56 is very difficult to get dirty and hardly deteriorates in insulation, the frequency of cleaning can be greatly reduced as compared with the prior art, and the operating rate of the apparatus is greatly improved.

  Further, the second support 46 for supporting the ground electrode 14 and the high-potential electrode 12, the first support 40, and the high-potential support rod 54 are electrically insulated by a space without interposing an insulator. The problem that the contaminants adhere to the insulator of the extraction electrode system 10 to cause insulation deterioration does not occur at all. That is, the problem corresponding to the insulation deterioration of the insulator 16 that has occurred in the prior art does not occur at all. Therefore, for this reason, the operating rate of the apparatus is greatly improved.

  Further, the high potential electrode 12 is supported by the high potential support rod 54 and the first support body 40, and a high voltage can be applied to the high potential electrode 12 from outside the ion source chamber 2 via these. Since no wiring for applying a high voltage to the high potential electrode 12 is required in the chamber 2, it is possible to eliminate the poor workability of the wiring to the high potential electrode, which the prior art has.

  Further, as in this embodiment, if the support rod hole 52 is provided on the downstream side of the position where the second support 46 is coupled to the electrode system support shaft 50, the second support 46 and the grounding are provided. Since the electrode 14 can block the contaminant from entering the support rod hole 52, contamination of the insulator 56 can be more effectively suppressed. Therefore, the operating rate of the apparatus can be further improved.

  In addition, when the cylindrical insulator 58 is provided on the insulator 56 as in this embodiment, the creeping insulation distance of the insulator 56 (specifically, the distance from the electrode system support shaft 50 to the high level) The creeping insulation distance facing the support rod hole 52 between the potential support rod 54 and the potential support rod 54 becomes longer, so that the insulation deterioration of the insulator 56 can be further suppressed. Therefore, the operating rate of the apparatus can be further improved.

  Note that the first support 40 supports the support 44 and may have a structure in which the hole 43 is provided in a support plate 42 having a circular shape, a square shape, or a shape close thereto, as in the example shown in FIG. A structure in which a space 43a is provided around the cylindrical electrode 36 by using a U-shaped support plate 42 that supports the column 44 and has an open side.

  Further, the second support 46 may have a structure in which the hole 47 is provided in a circular, quadrangular or plate-like shape having a shape close thereto, or a shape close to a T-shape as in the example shown in FIG. As a plate-like structure, a space 47 a may be provided around the second support body 46 and between the pillars 44.

  Further, instead of providing the second support 46, the ground electrode 14 is extended to connect the ground electrode 14 to the end of the electrode system support shaft 50 inside the ion source chamber 2, and the ground electrode 14 has a high potential. The electrode 12, the first support 40, and the high-potential support rod 54 may be electrically insulated by a space without using an insulator.

  In this case as well, as in the case of using the second support 46, if the support rod hole 52 is provided downstream of the position where the ground electrode 14 is coupled to the electrode system support shaft 50, the ground electrode 14, the contaminants can be prevented from entering the support rod hole 52, so that the contamination of the insulator 56 can be more effectively suppressed. Therefore, the operating rate of the apparatus can be further improved.

It is a schematic sectional drawing which shows one Embodiment of the ion source apparatus which concerns on this invention. It is the schematic front view seen in the arrow DD direction of FIG. It is a schematic sectional drawing which shows an example of the conventional ion source apparatus. It is sectional drawing which shows the detailed example around the insulator in FIG. It is a schematic front view which shows the other example of the surroundings of a 1st support body. It is a schematic front view which shows the other example around a 2nd support body.

Explanation of symbols

2 Ion source chamber 4 Plasma generator 8 Ion beam 10 Extraction electrode system 12 High potential electrode 14 Ground electrode 40 First support 46 Second support 50 Electrode system support shaft 52 Support rod hole 54 High potential support rod 56 Insulator 58 Cylindrical insulator 72 Bellows

Claims (4)

A plasma generation unit that generates plasma in an ion source chamber that is evacuated to vacuum, and an electrode system that extracts an ion beam from the plasma in the plasma generation unit, the high potential electrode to which a high voltage is applied, and the high potential In an ion source device having a structure in which an extraction electrode system having a ground electrode having a ground potential provided on the downstream side of the electrode is disposed,
An electrode system support shaft having a ground potential, which has a hole for a support rod penetrating in the axial direction inside the ion source chamber,
A vacuum sealing means for vacuum-sealing between the electrode system support shaft and the ion source chamber;
A hole for the support rod of the electrode system support shaft is penetrated with a space between the electrode system support shaft and a high voltage is applied near the outer end of the ion source chamber. A high potential support rod;
The electrode system support shaft is provided in the support rod hole in the vicinity of the outer end of the ion source chamber, and is provided between the electrode system support shaft and the high potential support rod to electrically insulate them from each other. And an insulator for supporting the high potential support rod,
A packing for vacuum-sealing between the insulator and the electrode system support shaft and the high-potential support rod;
A first support coupled to the inner end of the ion source chamber of the high potential support rod and supporting the high potential electrode and electrically conducting the high potential electrode to the high potential support rod;
The electrode system support shaft is coupled to the inner end of the ion source chamber, supports the ground electrode, and electrically connects the ground electrode to the electrode system support shaft, the high potential An ion source device comprising: an electrode, a second support that is electrically insulated by a space without an insulator between the first support and the high-potential support rod.   Instead of providing the second support, the ground electrode is coupled to an end of the electrode system support shaft inside the ion source chamber, and the ground electrode, the high potential electrode, the first support, and the The ion source device according to claim 1, wherein the ion source device is electrically insulated from the high potential support rod by a space without an insulator.   3. The ion source device according to claim 1, wherein the support rod hole is provided downstream of a position where the second support or the ground electrode is coupled to the electrode system support shaft.   The insulator protrudes from the insulator toward the inside of the ion source chamber. The insulator surrounds the high-potential support bar with a space, and opens a space between the electrode system support shaft and the insulator. The ion source device according to claim 1, 2 or 3, further comprising a cylindrical insulator.

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