ion gun

Abstract

The ion gun of the present invention comprises an anode, an inner surface facing the anode, a slit installed at a position corresponding to the anode, a magnetic pole having an inner inclined surface that extends from one end of the inner surface toward the slit and forms a part of the slit, and a cover that covers at least the inner surface and the inner inclined surface and is composed of a conductive and non-magnetic material and is detachable from the magnetic pole.

Description

Technology Field

[0001] The present invention relates to an ion gun.

[0002] The present application claims priority based on Japanese Patent Application No. 2019-163763 filed on September 9, 2019, and incorporates the contents thereof herein. Background Technology

[0003] Conventionally, processes utilizing ion beams extracted from ion guns are widely used, and ion guns are installed in various devices. Generally, an ion gun has a structure that generates plasma between a slit formed on a magnetic pole (cathode) and an anode (positive electrode) and extracts an ion beam to the outside through the slit (see, for example, Patent Document 1). Prior art literature

[0004] Specification of U.S. Patent Application Publication No. 2012 / 0187843 The problem to be solved

[0005] Recently, there has been a demand for processes that increase the magnetic field strength of the ion gun and improve the etching rate of the workpiece. However, in such processes, the magnetic poles are easily consumed by the plasma, which leads to a problem where the slit gap of the magnetic poles widens and the discharge current decreases. In addition, there is a problem of reduced maintainability because the frequency of replacing consumed magnetic poles with new ones increases. Furthermore, along with the consumption of the magnetic poles, contamination caused by the material of the magnetic poles occurs, which has an adverse effect on the process using the ion gun.

[0006] The present invention has been made in consideration of these circumstances and aims to provide an ion gun capable of suppressing the consumption of the stimulus in the stimulus slit, improving maintainability by reducing the frequency of stimulus replacement, and suppressing the occurrence of contamination caused by the stimulus material. means of solving the problem

[0007] An ion gun according to one embodiment of the present invention comprises an anode, an inner surface facing the anode, a slit installed at a position corresponding to the anode, a magnetic pole having an inner inclined surface that extends from one end of the inner surface toward the slit and forms a part of the slit, and a cover that covers at least the inner surface and the inner inclined surface and is composed of a conductive and non-magnetic material and is detachable from the magnetic pole.

[0008] In an ion gun according to one embodiment of the present invention, the cover may comprise a first covering portion covering the inner surface of the stimulus and a second covering portion connected to the first covering portion and covering the inner inclined surface.

[0009] In an ion gun according to one embodiment of the present invention, the second covering portion of the cover has a vertical plane extending in a vertical direction with respect to the anode, and in the slit, the vertical planes facing each other may be parallel.

[0010] In an ion gun according to one embodiment of the present invention, the inner inclined surface of the stimulus has an inner tip located on the opposite side from the end of the inner surface, and in a planar view of the ion gun, the inner tip and the vertical plane of the cover may coincide.

[0011] In an ion gun according to one embodiment of the present invention, the inner inclined surface of the stimulus has an inner tip located on the opposite side from the end of the inner surface, and in the planar view of the ion gun, the cover may have a protrusion that protrudes from the inner tip toward the slit.

[0012] In an ion gun according to one embodiment of the present invention, the stimulus has an outer surface opposite to the inner surface and an outer inclined surface that extends from one end of the outer surface toward the slit and forms a part of the slit, and the cover may cover the inner surface, the inner inclined surface, the outer surface, and the outer inclined surface.

[0013] In an ion gun according to one embodiment of the present invention, the material constituting the cover may be selected from the group consisting of carbon, titanium, and copper. In particular, it is preferable that the material constituting the cover be carbon. Effects of the invention

[0014] According to the above embodiment of the present invention, the consumption of the stimulus in the slit of the stimulus is suppressed, thereby improving maintainability by reducing the frequency of stimulus replacement, and also suppressing the occurrence of contamination caused by the material of the stimulus. Brief explanation of the drawing

[0015] [Fig. 1] This is a perspective view showing the schematic structure of a linear ion gun according to an embodiment of the present invention. [Fig. 2] This is a diagram showing the schematic structure of a linear ion gun according to an embodiment of the present invention, and is a cross-sectional view along line AA shown in Fig. 1. [Fig. 3] This is an enlarged cross-sectional view showing the main part of a linear ion gun according to an embodiment of the present invention. [Fig. 4] This is an enlarged cross-sectional view showing the main part of a linear ion gun according to Variant Example 1 of the present invention. [Fig. 5] This is an enlarged cross-sectional view showing the main part of a linear ion gun according to a modified example 2 of an embodiment of the present invention. [Fig. 6] This is an enlarged cross-sectional view showing the main part of a linear ion gun according to Variant Example 3 of the present invention. [Fig. 7] This is a graph showing experimental results illustrating an embodiment of the present invention. Specific details for implementing the invention

[0016] An ion gun according to an embodiment of the present invention will be described with reference to the drawings. In each drawing used to describe the present embodiment, the scale of each component is appropriately changed so that each component is recognizable in size.

[0017] In the following description, "plane view" means a plane viewed from above the ion gun, and means a plane viewed from the vertical direction of the stimulus (30) shown in FIG. 1 or FIG. 2 described later.

[0018] In addition, ordinal numbers such as "first," "second," etc. in the following embodiments are attached to avoid confusion of the components and do not limit the quantity.

[0019] (Linear Ion Gun)

[0020] FIG. 1 is a perspective view showing the schematic structure of a linear ion gun (ion gun) according to an embodiment of the present invention. FIG. 2 is a cross-sectional view along line AA of FIG. 1. FIG. 3 is a drawing showing the main part of a linear ion gun according to an embodiment of the present invention, and is an enlarged cross-sectional view showing a member around a slit formed in the excitation.

[0021] As illustrated in FIG. 1, the linear ion gun (10) is equipped with a yoke (20) and a magnetic pole (30). Inside the yoke (20), an anode (40), a magnet (50), an insulating part (70), and a gas supply device (G) are arranged (described later).

[0022] In the case of the stimulus (30), a cover (60) is mounted on the inner surface (32) of the stimulus (30) facing the anode (40) (described later).

[0023] The linear ion gun (10) has a simple configuration that eliminates the need for extraction electrodes such as grid electrodes, and can generate plasma (P) and ion beam (BM) through ion acceleration using a single DC power source (Direct Current). In addition, since the linear ion gun (10) does not have a thermal filament, it can operate for a long time even in an oxygen atmosphere and has low cost and high reliability.

[0024] Additionally, although FIG. 1 shows only the linear ion gun (10), a moving device that moves or oscillates the linear ion gun (10) may be connected to the linear ion gun (10). Depending on the device using the linear ion gun (10), the structure of the moving device is appropriately selected.

[0025] As illustrated in FIG. 1, the linear ion gun (10) has a track-shaped opening (11) having a straight section and a curved section. The curved section (corner section) of the opening (11) has a radius of curvature of, for example, 25 mm in a flat state.

[0026] (York)

[0027] The yoke (20) is an iron frame-shaped member that surrounds the anode (40), magnet (50), insulating part (70), and gas supply device (G). The area surrounded by the yoke (20) is covered with a magnetic pole (30).

[0028] (stimulation)

[0029] The magnetic pole (30) (negative pole) has a size of, for example, 400 mm in total length × 100 mm in width × 10 mm in height when viewed in a planar state. As the material constituting the magnetic pole (30), a ferromagnetic material is preferably used, and for example, steel such as SS400 or stainless steel such as SUS430 is used.

[0030] As illustrated in FIG. 3, the stimulus (30) has a slit (31) installed at a position corresponding to the anode (40). The slit (31) is installed at a position corresponding to the opening (11).

[0031] The stimulus (30) is fixed to the yoke (20) by a fastening member. By releasing the fixation by the fastening member, the stimulus (30) can be detached from the yoke (20). Specifically, the stimulus (30) has an inner stimulus (30I) located inside the opening (11) and an outer stimulus (30E) located outside the opening (11).

[0032] The inner stimulator (30I) is fixed to the yoke (20) in advance. Meanwhile, the outer stimulator (30E) is detachable from the yoke (20). It is possible to remove the outer stimulator (30E) by releasing the fixation by the fastening member while maintaining the fixed state of the inner stimulator (30I).

[0033] Additionally, as a structure of the stimulation (30), it is acceptable for each of the inner stimulation (30I) and the outer stimulation (30E) to be independently detachable from the yoke (20).

[0034] Also, FIG. 1 shows that the outer stimulator (30E) is a single plate member, but the outer stimulator (30E) may be composed of multiple plate members. In this case, each of the multiple plate members can be independently detached from the yoke (20) by releasing the fixation by the fastening member.

[0035] The stimulus (30) has an inner surface (32) facing the anode (40) and an outer surface (33) on the opposite side of the inner surface (32). In addition, the stimulus (30) has an inner inclined surface (38) that forms part of the slit (31) while extending from one end of the inner surface (32) toward the slit (31), and an outer inclined surface (35) that forms part of the slit while extending from one end of the outer surface (33) toward the slit (31).

[0036] The inner slope surface (38) is a slope surface that extends upward obliquely from the end (39) (one end, bottom) of the inner surface (32) adjacent to the slit (31) toward the center of the slit (31), and forms a part of the slit (31).

[0037] The outer slope surface (35) is a slope surface that extends downward obliquely from the end (34) (one end, top) of the outer surface (33) adjacent to the slit (31) toward the center of the slit (31), and forms a part of the slit (31).

[0038] The inner slope (38) of the stimulus (30) has an inner end (36) located on the opposite side from the end (39) (one end) of the inner surface (32). In other words, the outer slope (35) of the stimulus (30) has an inner end (36) located on the opposite side from the end (34) (one end) of the outer surface (33). That is, the inner end (36) is a connecting end where the inner slope (38) and the outer slope (35) are connected.

[0039] The distance between the opposing inner ends (36), that is, the width of the slit (31), is about 3 mm. Additionally, the width of the slit (31) is not limited to this value.

[0040] (Anode)

[0041] The anode (40) (positive electrode) is positioned apart from the back side of the magnetic pole (30) so as to generate an electric field in a direction approximately perpendicular to the magnetic field generated by the magnet (50). An unillustrated DC power supply is connected to the anode (40).

[0042] It is preferable to use a non-magnetic material for the material constituting the anode (40).

[0043] The anode (40) is supported by the insulating part (70) inside the yoke (20).

[0044] (magnet)

[0045] The magnet (50) is composed of an SmCo (samarium cobalt) alloy and generates a magnetic field in the width direction of the slit (31). Additionally, NdFe (neodymium iron) may be used for the magnet (50).

[0046] (Gas supply device)

[0047] A gas supply device (G) is installed inside the yoke (20) and supplies a gas such as Ar or O2 into the yoke (20). The gas from the gas supply device (G) flows through the inside of the yoke (20) toward the opening (11) and is used to generate plasma between the slit (31) of the excitation (30) and the anode (40).

[0048] On the outer circumference of the yoke (20) or anode (40), an unillustrated water cooling pipe connected to a cooling water circulation device is installed. By allowing a cooling medium to flow through the water cooling pipe, deformation of the excitation (30) or anode (40) is prevented, making it possible to stably operate the linear ion gun (10) without relying on temperature.

[0049] (sleeve)

[0050] The cover (60) covers the inner surface (32) and inner inclined surface (38) of the stimulus (30) and is composed of a conductive and non-magnetic material. The cover (60) is separate from the stimulus (30) and is fixed to the stimulus (30) by a fastening member. By releasing the fixation by the fastening member, the cover (60) can be detached from the stimulus (30).

[0051] The cover (60) has a first covering part (61) that covers the inner surface (32) of the stimulus (30), and a second covering part (62) that is connected to the first covering part (61) and covers the inner inclined surface (38). That is, the first covering part (61) and the second covering part (62) are a single piece.

[0052] In this embodiment, the second covering portion (62) has a vertical plane (63) that extends vertically with respect to the anode (40). In the slit (31), the vertical planes (63) facing each other are parallel. The vertical planes (63) are exposed to the opening (11) in the slit (31).

[0053] Also, in the planar view of the linear ion gun (10), the inner end (36) of the stimulus (30) aligns with the vertical plane (63) of the cover (60).

[0054] It is preferable that the cover (60) be composed of a material that is less susceptible to erosion compared to the stimulating material. The cover (60) is composed of a conductive and non-magnetic material, and specifically, the material constituting the cover (60) is selected from the group consisting of carbon, titanium, and copper. In particular, it is most preferable to use carbon as this material.

[0055] Regarding the characteristics of carbon suitable for use as a cover (60), it is preferable that the bending strength be 34 MPa to 74 MPa, the tensile strength be 22 MPa to 48 MPa, the resistivity be 11 μΩ·m to 17.5 μΩ·m, and the Shore hardness be 53 to 87. By using carbon having these characteristics, a cover (60) suitable for this embodiment can be formed.

[0056] Next, the operation of the linear ion gun (10) configured as described above will be explained.

[0057] The linear ion gun (10) is placed in a chamber where a reduced pressure atmosphere is maintained. In the linear ion gun (10), while gas is supplied from a gas supply device (G) to the space between the anode (40) and the excitation (30), a high-frequency voltage is applied between the anode (40) and the excitation (30) by a DC power source. Accordingly, as shown in FIG. 2, plasma (P) is generated between the excitation (30) and the anode (40), and an ion beam (BM) is drawn out from the opening (11).

[0058] According to the present embodiment, the inner inclined surface (38) of the stimulator (30) constituting the slit (31) in the opening (11) is covered by a cover (60), so the inner inclined surface (38) of the stimulator (30) is not exposed inside the slit (31). Because of this, the wear of the inner inclined surface (38) caused by the inner inclined surface (38) being exposed to plasma inside the slit (31) is suppressed, and the increase in the gap of the slit (31) (distance between two inner ends (36)) caused by the wear of the inner inclined surface (38) can be prevented. As a result, a predetermined gap is maintained in the slit (31), and a decrease in discharge current can be prevented. In addition, the lifespan of the stimulator (30) is extended, and the frequency of replacing a used stimulator with a new one is reduced, thereby improving maintainability. In addition, since the consumption of the stimulus (30) is suppressed, the occurrence of contamination caused by the material of the stimulus (30) can be suppressed, so there is no adverse effect on the process using the ion gun.

[0059] In this embodiment, the cover (60) is composed of a material that is less prone to corrosion than the stimulating material and is composed of carbon. Since carbon has a sputtering efficiency of about 1 / 3 compared to a general stimulating material, it can be suitably used as the material for the cover (60).

[0060] Additionally, even if the operating time of the linear ion gun (10) has elapsed, the effect of suppressing the consumption of the stimulus (30) can be obtained, but on the other hand, the cover (60) is consumed sacrificially. However, the cover (60) can be easily detached from the stimulus (30), so the cover (60) can be replaced.

[0061] (Replacement of cover)

[0062] When exchanging the new and old covers (60) for the stimulation (30), the outer stimulation (30E) is first removed from the yoke (20). In this state, the cover (60) becomes detachable from the inner surface (32) of the outer stimulation (30E). Furthermore, when the outer stimulation (30E) is removed from the yoke (20), the operator can insert their finger between the inner stimulation (30I) and the anode (40). Because of this, the cover (60) becomes detachable from the inner surface (32) of the inner stimulation (30I).

[0063] For this reason, the used cover (60) can be easily removed from the outer stimulation (30E) and the inner stimulation (30I). After that, a new cover (60) before use can be easily attached to the outer stimulation (30E) and the inner stimulation (30I).

[0064] Also, since the magnetic force (magnetic flux) of the outer stimulus (30E) is smaller than that of the inner stimulus (30I), the operation of attaching and detaching the outer stimulus (30E) from the yoke (20) can be easily performed.

[0065] (Variations of embodiments)

[0066] Next, with reference to FIGS. 4 to 6, a linear ion gun according to a modified embodiment of the present invention will be described. In FIGS. 4 to 6, the same reference numerals are used for components identical to those in the previously described embodiment, and their descriptions are omitted or simplified. The modified embodiment described below differs from the previously described embodiment in terms of the structure of the cover (60).

[0067] (Variation Example 1)

[0068] FIG. 4 is an enlarged cross-sectional view showing the main part of a linear ion gun according to Variant Example 1 of an embodiment of the present invention.

[0069] In the above-described embodiment, the structure was explained such that the inner tip (36) of the stimulus (30) aligns with the vertical plane (63) of the second covering (62) in the planar view of the linear ion gun (10), but the inner tip (36) does not need to align with the vertical plane (63).

[0070] Specifically, in Variation Example 1, the cover (60) has a protrusion (64) that protrudes from the inner end (36) toward the interior of the opening (11) in the planar view of the linear ion gun (10).

[0071] According to the first variation of this example, since a protrusion (64) is positioned between the inner end (36) of the stimulus (30) and the plasma generation area, the inner end (36) is less likely to be exposed to plasma, and the effect of suppressing the consumption of the stimulus (30) can be further enhanced. Accordingly, the increase in the gap of the slit (31) caused by the consumption of the stimulus (30) can be prevented. As a result, a predetermined gap is maintained in the slit (31), preventing a decrease in the discharge current, and thus extending the lifespan of the stimulus (30).

[0072] Additionally, the amount of protrusion of the protrusion (64), that is, the distance from the inner tip (36) to the vertical plane (63) (the tip of the protrusion (64)), is appropriately determined according to the frequency of replacement of the cover (60) during maintenance of the linear ion gun (10) and the flow rate of gas flowing to the outside of the linear ion gun (10) through the opening (11).

[0073] Specifically, if the protrusion amount of the protrusion (64) increases, the frequency of replacing the cover (60) can be reduced, but on the other hand, the opening area of ​​the opening (11) becomes smaller and the conductance decreases, so the gas flow rate through the opening (11) decreases. In contrast, if the protrusion amount of the protrusion (64) decreases, the frequency of replacing the cover (60) increases, but the opening area of ​​the opening (11) becomes larger and the conductance increases, so the gas flow rate through the opening (11) increases.

[0074] That is, the protrusion amount of the protrusion (64) and the gas flow rate required for the linear ion gun (10) are in a trade-off relationship. The protrusion amount of the protrusion (64) is determined by taking this relationship into account.

[0075] (Variation Example 2)

[0076] FIG. 5 is an enlarged cross-sectional view showing the main part of a linear ion gun according to a modified example 2 of an embodiment of the present invention.

[0077] In the above-described embodiment and variation 1, the case where the cover (60) has a vertical surface (63) was described, but the cover (60) does not necessarily have to have a vertical surface (63).

[0078] As illustrated in FIG. 5, the second covering portion (62) of the cover (60) may have a protrusion (64) that protrudes from the inner end (36) toward the interior of the opening (11) in the planar view of the linear ion gun (10), and may also have an inclined surface parallel to the inner inclined surface (38). In this case, the inclined surface of the second covering portion (62) is exposed to the opening (11) in the slit (31).

[0079] According to the second variation of this example, since a protrusion (64) is positioned between the inner end (36) of the stimulus (30) and the plasma generation area, the inner end (36) is less likely to be exposed to plasma, and the effect of suppressing the consumption of the stimulus (30) can be further enhanced. Accordingly, the increase in the gap of the slit (31) caused by the consumption of the stimulus (30) can be prevented. As a result, a predetermined gap is maintained in the slit (31), preventing a decrease in the discharge current, and thus extending the lifespan of the stimulus (30).

[0080] Additionally, just like in Variation Example 1, the amount of protrusion of the protrusion (64) and the gas flow rate required for the linear ion gun (10) are in a trade-off relationship, so the amount of protrusion of the protrusion (64) is determined by taking this relationship into account.

[0081] (Variation Example 3)

[0082] FIG. 6 is an enlarged cross-sectional view showing the main part of a linear ion gun according to Variant Example 3 of the present invention.

[0083] In the above-described embodiments and variations 1 and 2, the inner surface (32) of the stimulus (30) is covered with a first covering part (61) and the inner slope surface (38) is covered with a second covering part (62). However, the cover (60) may cover at least the inner surface (32) and the inner slope surface (38), and the cover (60) may cover the outer surface (33) and the outer slope surface (35).

[0084] As illustrated in FIG. 6, the cover (60) has a first covering part (61) covering the inner surface (32), a second covering part (62) covering the inner sloped surface (38), a third covering part (66) covering the outer surface (33), and a fourth covering part (67) covering the outer sloped surface (35). The fourth covering part (67) is connected to the third covering part (66). The third covering part (66) and the fourth covering part (67) are integral parts and are fixed to the stimulator (30) by means of a fastening member. By releasing the fixation by the fastening member, the third covering part (66) and the fourth covering part (67) can be detached from the stimulator (30).

[0085] The first covering part (61) and the second covering part (62) constitute the lower cover. The third covering part (66) and the fourth covering part (67) constitute the upper cover. The lower cover and the upper cover are separate from each other, and each of the lower cover and the upper cover is fixed to the stimulus (30).

[0086] According to the third variation, not only can the same effect as the above-described embodiment be obtained, but the consumption of the stimulus (30) on the outer surface (33) and the outer slope surface (35) can also be suppressed.

[0087] Additionally, in the structure illustrated in FIG. 6, a protrusion (64) may be installed on the vertical surface (63), and a protrusion may be installed on the vertical surface of the fourth covering (67). Also, the protrusion (64) shown in Variation Example 2 may be applied to Variation Example 3.

[0088] However, as described above, since the protrusion amount of the protrusion (64) and the gas flow rate required for the linear ion gun (10) are in a trade-off relationship, the protrusion amount of the protrusion (64) is determined by taking this relationship into account.

[0089] In the above-described embodiments and variations 1 to 3, two inner inclined surfaces (38) and two outer inclined surfaces (35) are installed inside the slit (31) and arranged in a line-symmetric manner (line-symmetric with respect to the center line of the slit) while facing each other. In other words, in this structure, two corners facing each other with the inner end (36) as the apex are located inside the slit (31).

[0090] In this line-symmetric structure, even if the stimulus (30) inside the slit (31) is consumed, the line-symmetric shape (similar relationship) is maintained, so the discharge current does not decrease, and the stable trend (time-dependent change) of the discharge current is maintained.

[0091] Maintaining a similarity relationship of shape is almost the same as the condition (change) of magnetic flux density occurring inside the slit (31) depending only on the spacing of the slit (31). This means that no fluctuation in the magnetic flux distribution caused by changes in the surface shape of the magnetic pole (30) inside the slit (31) occurs.

[0092] The inventors confirmed the mutual contribution evaluation of the spacing of the slit (31) and the change in the surface shape of the stimulus (30) inside the slit (31) by simulation.

[0093] As a result, it was found that when the purpose is to stabilize the ion current, maintaining the similarity of the shapes of opposing magnetic poles (30) inside the slit (31) is a dominant factor in realizing the stabilization of the ion current, rather than changing the spacing of the slit (31). It was confirmed that this evaluation result is consistent with the example (experimental result) described later.

[0094] Examples

[0095] Next, with reference to FIG. 7 and the examples, the effects of the present invention will be explained in more detail.

[0096] FIG. 7 is a graph comparing a comparative example showing a conventional linear ion gun with an embodiment showing a linear ion gun with a cover applied according to the above-described embodiment, showing the temporal change in discharge current accompanying the passage of operating time (operation time). In FIG. 7, the horizontal axis represents the operating time of the linear ion gun, and the vertical axis represents the change in discharge current. Specifically, the change in discharge current refers to the relative amount of change in discharge current based on the case where the operating time is 0 hours (1, 100%).

[0097] (Comparative Example)

[0098] In the linear ion gun of the comparative example, a structure in which a cover is not installed on the slit of the stimulation, that is, a structure in which the constituent member of the stimulation is exposed in the slit, is applied.

[0099] In the comparative example, the discharge current decreased significantly immediately after the start of operation. After that, the discharge current gradually decreased until the operating time reached 7.5 hours. Even after the operating time of 7.5 hours had passed, the phenomenon of the discharge current decreasing continued. When the operating time reached 17 hours, the amount of change in the discharge current was 0.8, and the discharge current decreased by about 20% compared to before the start of operation. In addition, after the operating time reached 17 hours, the consumption of the excitation in the linear ion gun of the comparative example was checked, and it was confirmed that a shape change caused by consumption occurred in the part corresponding to the inner end (36) of the excitation (30) of the present embodiment.

[0100] (Example)

[0101] In the linear ion gun of this embodiment, the structure shown in the above-described embodiment (Fig. 3) is applied.

[0102] In this embodiment, from the start of operation until the operating time reached 5 hours, the discharge current gradually decreased, but no significant decrease in the discharge current shown in the comparative example was observed. When the operating time exceeded 5 hours, no decrease in the discharge current was observed, and the discharge current stabilized. When the operating time reached 17 hours, the change in the discharge current was 0.9, and the discharge current decreased by about 10% compared to before the start of operation.

[0103] When comparing the comparative example and the embodiment, it became clear that after 17 hours of operation, the embodiment can suppress the decrease in discharge current by about 10% compared to the comparative example. That is, the structure in which the cover (60) shown in the above embodiment is installed on the stimulus (30) contributes to suppressing the decrease in discharge current.

[0104] The preferred embodiments of the present invention have been described above. However, it should be understood that these are exemplary embodiments of the present invention and should not be considered limiting. Additions, omissions, substitutions, and other modifications may be made without departing from the scope of the present invention. Accordingly, the present invention should not be considered limited by the foregoing description, but is limited by the claims. Industrial applicability

[0105] The present invention is widely applicable to ion guns that suppress the consumption of the stimulus in the stimulus slit, improve maintainability by reducing the frequency of stimulus replacement, and suppress the occurrence of contamination caused by the stimulus material. Explanation of the symbols

[0106] 10: Linear ion gun (ion gun), 11: Opening, 20: York, 30: Stimulation, 30E: External stimulus (stimulation), 30I: Medial stimulation (stimulation), 31: Slit, 32: Inner self, 33: Turning away, 34, 39: End, 35: Outer slope, 36: Inner fleet, 38: Inner slope, 40: Anode, 50: Magnet, 60: Cover, 61: First covering (cover), 62: Second covering (cover), 63: Vertical plane, 64: Protrusion, 66: Third covering (cover), 67: 4th covering (cover), 70: Insulating part, BM: Ion beam, G: Gas supply device, P: Plasma.

Claims

Claim 1 An ion gun comprises an anode, an inner surface facing the anode, a slit installed above the anode and at a position corresponding to the anode, a magnetic pole having an inner inclined surface that extends from one end of the inner surface toward the slit and forms a part of the slit, and a cover that covers at least the inner surface and the inner inclined surface and is composed of a conductive and non-magnetic material and is detachable from the magnetic pole, wherein the cover comprises a first covering portion covering the inner surface of the magnetic pole and a second covering portion connected to the first covering portion and covering the inner inclined surface, wherein the inner inclined surface of the magnetic pole has an inner end located on the opposite side from the one end of the inner surface, and in a plane viewed from above the ion gun, the cover has a protrusion that protrudes from the inner end toward the slit. Claim 2 In claim 1, the second covering portion of the cover has a surface extending in the direction viewed from above the ion gun, and in the slit, the surfaces of the second covering portion facing each other are parallel, ion gun. Claim 3 An ion gun comprises an anode, an inner surface facing the anode, a slit positioned above the anode and corresponding to the anode, a magnetic pole having an inner inclined surface extending from one end of the inner surface toward the slit and forming a part of the slit, and a cover that covers at least the inner surface and the inner inclined surface and is composed of a conductive and non-magnetic material and is detachable from the magnetic pole, wherein the cover comprises a first covering portion covering the inner surface of the magnetic pole and a second covering portion connected to the first covering portion and covering the inner inclined surface, wherein the second covering portion of the cover has a surface extending in the direction viewed from above the ion gun, wherein the surfaces of the second covering portions facing each other in the slit are parallel, and the inner inclined surface of the magnetic pole has an inner end positioned opposite to the one end of the inner surface, and in a plane viewed from above the ion gun, the inner end and the second Ion gun that matches the surface of the covering. Claim 4 An ion gun according to any one of claims 1 to 3, wherein the stimulus has an outer surface opposite to the inner surface and an outer inclined surface that forms a part of the slit while extending from one end of the outer surface toward the slit, and the cover covers the inner surface, the inner inclined surface, the outer surface, and the outer inclined surface. Claim 5 An ion gun according to any one of claims 1 to 3, wherein the material constituting the cover is selected from the group consisting of carbon, titanium, and copper. Claim 6 In paragraph 5, the material constituting the cover is carbon, an ion gun. Claim 7 delete Claim 8 delete

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