TWI478198B - Ion guns and the grid used - Google Patents

Description

Ion gun and the grid used

The present invention relates to ion guns, and more particularly to an accelerating grid for extracting an ion beam from a plasma and an ion gun using the same.

Fig. 11 shows the configuration of a conventional ion gun 100. The ion gun 100 includes a body 110 for generating plasma therein, a shield grid 121 provided with a plurality of grid holes, and an acceleration grid 122 (referred to collectively as the grid 120), and is mounted on the support of the body 110. The seat 112 and the screw 140 that fixes the acceleration grid 122 to the support base 112. The accelerating grid 122 to which a voltage is applied from a power source (not shown) extracts ions from the plasma inside the body 110, thereby emitting an ion beam (arrow). The ion beam is applied to a piezoelectric element (not shown) or the like, and is used for frequency adjustment of the piezoelectric element (for example, see Patent Document 1).

Although the grid 120 shown in Fig. 11 has a planar shape, it is known that the grid 120 is bent for the purpose of improving the convergence of the ion beam. For example, in Patent Document 2, a grid (electrode 8) which is curved so as to be recessed toward the body (ion source 5) side is disclosed, and Patent Document 3 also discloses a method of recessing toward the side of the body (symbol 5). Curved grid (plurality of plates 7). These grids are referred to as half-tube grids.

[Previous Technical Literature]

[Patent Document 1] Japanese Patent No. 4048254

[Patent Document 2] Japanese Patent Laid-Open No. 4-6272

[Patent Document 3] Japanese Unexamined Gazette No. 63-18746

However, the ion gun using the conventional half-tube type grid has the following problems.

First, in Patent Documents 2 and 3, in the manufacture of the grid, the planar grid plate is bent in a single direction and then mounted on the body, but it is difficult to ensure the accuracy of the bending process, and it is easy to generate in the curvature. Uneven processing. In the ion gun, the grid is consumables and is replaced relatively frequently. However, due to the uneven bending process, there is a problem that the characteristics of the emitted ion beam change each time the grid is replaced. Therefore, in the conventional half pipe type grid, since the bending process is uneven, there is a problem that the reproducibility of the emitted ion beam is poor.

Second, in the configuration of the conventional ion gun (the half tube type of Patent Documents 2 and 3 or the flat type of Patent Document 1), the shape stability of the acceleration grid is poor, and the output characteristics are obtained from the start of the ion beam emission. It takes a lot of time to settle down. That is, after the ion beam is started to be emitted, when the temperature of the acceleration grid rises, the deformation caused by the thermal expansion causes the position of the grid mesh to change with respect to other members, and thus it is necessary to wait until the change reaches the stability (for example, In the case of Patent Document 1, it takes about 15 minutes to start using the ion gun (for example, the operation of starting the frequency adjustment of the piezoelectric element). Therefore, since the shape stability is poor, there is a problem that power and waiting time are wasted from when the ion beam is emitted to when the stability is reached.

Third, as described above, since the grid is a consumable item, the user of the ion gun must store a plurality of grids in advance. However, in the grid which is curved as in Patent Documents 2 and 3, the occupied volume is large, and in order to prevent the bending state from being damaged during storage, it is necessary to avoid stacking a plurality of meshes at a time, so that it is necessary to prepare a wide storage and storage place. . Therefore, the conventional half pipe type grid also has a problem of poor storage.

Accordingly, an object of the present invention is to provide a half-tube type grid having reproducibility of output characteristics at the time of grid replacement, shape stability with temperature change, and good storage stability, and an ion gun including the same.

The first aspect of the present invention is an ion gun, that is, a body that generates plasma inside, a grid for extracting plasma from the inside of the body, and a grid between the body and the body. a frame-shaped accelerating electrode; an end surface of the body opposite to the grid has a valley-shaped curved surface; and the grid is mounted by a curved surface formed on the close surface of the body and the grid to conform to the curved surface The ion gun of the flat grid.

The second aspect of the present invention is an ion gun, that is, a body that generates plasma inside, a grid for extracting plasma from the inside of the body, and a grid between the body and the body. a frame-shaped accelerating electrode; an end surface of the accelerating electrode facing the grid has a mountain-like curved surface; and the grid is formed by a curved surface conforming to the curved surface on the adhesion surface between the accelerating electrode and the grid Ion gun with a flat grid.

The third aspect of the present invention is an ion gun, that is, a body having a plasma generated therein, a grid for extracting plasma from the inside of the body, and a fixture for fixing the grid to the body; The end face opposite to the grid has a valley-shaped curved surface; the grid is an ion gun of a flat grid mounted on a surface of the body and the mesh which is formed to conform to the curved surface .

A fourth aspect of the present invention is an ion gun in which a grid mesh is continuously formed from one end of the grid to the opposite end, and the grid is oriented perpendicular to the continuously formed grid mesh. Bend up. Further, the ion gun grid of the fourth type is preferably used in combination with a shielding plate which is open only in the effective area of the ion beam. The grid can be bent in the column direction.

In the ion gun of the first type to the fourth type, the grid holes of the grid may be arranged in parallel in the row direction of the piezoelectric elements arranged in a matrix, and the ion beam may be irradiated in the column direction in units of rows. The transferred piezoelectric element is ion-etched at the resonant frequency of the piezoelectric element.

The grid used in the first to fourth modes described above is made of molybdenum and has a thickness of preferably 200 μm to 20 μm, particularly preferably 150 μm to 50 μm.

Example 1.

Fig. 1 and Fig. 2A and Fig. 2B show an ion gun 1 according to a first embodiment of the present invention. Fig. 1 is an exploded perspective view of the ion gun 1. Fig. 2A is a side view, and Fig. 2B is an upper view. The drawings and the drawings shown in the following embodiments are not depicted as scales, but are shown in an enhanced description.

The ion gun 1 is provided with a body 10 that internally generates plasma, a grid 20 for drawing plasma from the inside of the body 10, and a frame-like shape (ring-shaped) between the grid 20 and the body 10. The accelerating electrode 30, the end surface of the body 10 facing the grid 20, has a valley-shaped curved surface. The accelerating grid 22 is applied with a voltage from the power source 50 via the accelerating electrode 30, and ions are extracted from the plasma by the plurality of grid holes. Thereby, the ion beam (arrow) is emitted. The ion beam is applied to a piezoelectric element (not shown) or the like, and is used for frequency adjustment or the like of the piezoelectric element. However, the use thereof is not limited thereto.

As shown in Fig. 2A, the end face 11 of the body 10 on the grid 20 side is curved in a valley shape in a single direction, and the end face 31 of the accelerating electrode 30 on the grid 20 side has the same curvature as the end face 11 in a single direction. Bend into a valley. That is, the end surface 11 and the end surface 31 sandwich the grid 20 and are bent in the same single direction. In the drawings, the above description is simple, and the gap between the end surface 11 and the shield grid 21, and the accelerating grid 22 and the end surface 31 is displayed with a gap therebetween, but these are actually arranged in close contact with each other. The shielding grid 21 and the body 10 are maintained at the shielding potential, the acceleration grid 22 and the acceleration electrode 30 are maintained at the acceleration potential, and the shielding grid 21 and the acceleration grid 22 are disposed at predetermined intervals.

As shown in FIG. 2B, the accelerating electrode 30 is exposed at the central portion (grid hole 22a) of the accelerating grid 22, and has a frame-like (annular) shape in which the grid 20 is fixed to the peripheral portion.

Further, since the accelerating electrode 30 has a configuration in which the ion beam is surrounded, the accelerating electrode 30 can function as an electrostatic lens to improve the convergence of the ion beam.

The grid 20 is composed of a plurality of grids, and the side of the body 10 is referred to as a shield grid 21, and the side of the accelerating electrode 30 is referred to as an acceleration grid 22. Here, for simplification of the description, two grids 21 and 22 are shown, but a plurality of grids may be overlapped. In any case, these grids are collectively referred to as grid 20.

Fig. 3 shows a grid (in front of the mounting) in the grid 20. In Fig. 2A, the grid 20 is bent in a single direction. On the other hand, as shown in Fig. 3, the grid 20 before being mounted is flat. That is, the grid 20 is flat at the time of manufacture, but is attached to the body 10 as the end face 11 is bent in a single direction and pressed by the accelerating electrode 30. Therefore, even if the grid 20 is made of the same material (for example, molybdenum) as the grid shown in each patent document, it is a thinner plate, for example, the thickness is preferably 200 μm to 20 μm, and particularly preferably 150 μm to 50 μm. The so-called planar grid before installation means a grid that is substantially flat, and also contains a very small portion of the grid that is not flat, or that has only a minimal degree of curvature.

In the above configuration, the grid 20 is previously manufactured as a flat grid, and when mounted on the body 10 (for example, at the time of replacement), the grid 20 is bent by fitting the end surface 11 of the body 10, whereby the bending of the grid 20 can be eliminated. Reduced reproducibility of processing unevenness. Therefore, even if the grid as a consumable is replaced, the reproducibility of the emitted ion beam before and after the replacement can be ensured.

Further, in the above configuration, since the acceleration grid 22 is in contact with the accelerating electrode 30, the deformation of the grid 20 due to thermal expansion after the ion beam is started to be emitted only in the direction along the end surface 31 of the accelerating electrode 30. The deformation. Similarly, since the shield grid 21 abuts against the body 10, the deformation of the grid 21 caused by the thermal expansion after the ion beam is emitted is only deformed in the direction along the end surface 11 of the body 10. Therefore, the shape stability with respect to the temperature rise is good, and the time required from the start of the ion beam emission until the output reaches the stability is shortened more than ever. Specifically, even at the same output power, the time required for output stabilization is about 15 minutes in the example of Patent Document 1, whereas it can be confirmed that it is about 3 minutes in the present invention.

Further, since the grid 20 of the present invention is not a curved plate but is manufactured and stored as a flat plate, the treatment of the mesh 20 is facilitated before being mounted. In particular, the grid 20 of the flat plate can be stowed during storage, so that the storage space can be saved, and the storage property is good.

Example 2.

4A and 4B show the ion gun 2 of the second embodiment of the present invention in accordance with the manufacturing process. In the present embodiment, as in the first embodiment, the grids 20 used are all the flat grids 20, but the positions of the holes through which the fixtures and the like pass are different.

In FIG. 4A, the shield grid 21 is fixed to the end surface 11 of the body 10 by a fixture (for example, a screw) 41, and the acceleration grid 22 is fixed to the end surface 31 of the accelerating electrode 30 by a fixture (for example, a screw) 42. . Here, the configuration of the body 10 is basically the same as that of the first embodiment, but the electrode support base 12 is provided at a point of a part of the body 10, and the configuration of the screw holes is different. Further, the configuration of the accelerating electrode 30 is basically the same as that of the first embodiment, but the point for the concave portion 32 of the electrode supporting base 12 is provided, and the configuration of the screw hole is different. The electrode support 12 is electrically insulated from the body 10 and is applied with a voltage from the power source 50. Although omitted in the same figure, the electrode holder 12 is provided with a plurality of roots on the periphery of the body 10, and has an upper end to support the accelerating electrode 30. The shield grid 21 and the accelerating grid 22 are disposed by the electrode holder 12 while maintaining the distance between the grids and having a potential difference. The grid distance can be adjusted by the height of the electrode support 12 and the shape of the recess 32.

In FIG. 4B, the body 10 and the shielding grid 21, the acceleration electrode 30 and the acceleration grid 22 are mounted such that the electrode holder 12 converges in the recess 32, and are fixed by a fixture (for example, a screw) 43. To fix this. In the same figure, the fixing members 41 and 42 are omitted for the sake of clarity of the drawing. As shown in FIG. 4C, the grid 20 can also be directly fixed to the accelerating electrode 30 using the fixture 42, and the accelerating electrode 30 and the body 10 can be fixed by the fixture 43. A spacer made of an insulating material is disposed between the shielding grid 21 and the acceleration grid 22.

Example 3.

In the third embodiment, a configuration in which the accelerating electrode 30 is not used is shown as a modification of the first embodiment.

Fig. 5 is a side view showing the ion gun 3 of the present embodiment. As shown, the grid 20 is directly secured to the body 10 using fixtures 44. By arranging the fixture 44 appropriately, the grid 20 can be fixed in accordance with the bending of the body 10 even without using the accelerating electrode 30.

At this time, the voltage is directly applied from the power source 50 to the acceleration grid 22.

In the above configuration, although it is difficult to obtain the effect of the acceleration grid (that is, excellent shape stability, electrostatic lens action, etc.), as in the first and second embodiments, even if the grid as a consumable is replaced, Ensure the reproducibility of the outgoing ion beam before and after replacement, and the storage of the grid is also good.

Example 4.

6 to 9 show an ion gun 4 of a fourth embodiment of the present invention. Fig. 6A is a side view, Fig. 6B is a front view, and Fig. 6C is an upper view.

The ion gun 4 is an ion gun shown in the first embodiment, and is characterized in that the main body 60, the grid 70, and the frame-shaped accelerating electrode 80 have a rectangular shape. The configuration other than the shape and the grid 70 is the same as that of the first embodiment, and thus the description thereof is omitted. Further, the ion gun 4 can use the fixing means of the grid shown in the second embodiment, and the acceleration electrode 80 can be omitted as shown in the third embodiment. The rectangular ion gun is effective when frequency adjustment is performed on a plurality of piezoelectric elements arranged in a line, but the use is not limited thereto.

As shown in Fig. 6A, the end face 61 of the body 70 on the grid 70 side is curved in a valley shape in a single direction (the short side direction of the rectangle in the figure), and the end face 81 of the accelerating electrode 80 on the grid 70 side. The same curvature as the end surface 61 is curved in a valley shape in the same direction as the end surface 61. Further, in the shield grid 71 and the accelerating grid 72, a plurality of grid holes 71a, 72a are formed along one side of the rectangle. In the same figure, the grid holes 71a, 72a are formed in the central portion of the short side direction of the rectangle, and a plurality of strips are formed along the long sides to obtain a strip-shaped ion beam irradiation region parallel to the long sides. In the embodiment, since the hole is formed not only in the entire grid but also in the central portion in the short-side direction, both ends in the short-side direction with high strength can be adhered to the body and the accelerating electrode, and the grid can be easily formed. The plate is fitted to the curvature of the body and the accelerating electrode. Further, since both ends in the short-side direction having a large area are adhered to the body and the accelerating electrode, heat transfer is large, and deformation due to thermal expansion is less likely to occur.

Fig. 7 is an exploded perspective view showing the accelerating electrode 80 and the accelerating grid 72. Since the grid 70 is fixed by the curved body portion 60 and the peripheral portion of the accelerating electrode 80, the reproducibility and shape stability are excellent, and the accelerating electrode 80 surrounding the ion beam acts as an electrostatic lens to increase the ion beam. The effect of the convergence is the same as that of the first embodiment.

Figure 8 is an exploded perspective view showing another embodiment of the grid 70. The accelerating grid 73 is characterized in that the grid mesh is continuously formed from one end of the grid to the opposite end, and the grid is bent in a direction parallel to one end and the other end of the grid. In Fig. 7, since the strength of the plate differs from the place where there is no mesh in the mesh hole, it may not be uniform curvature, but in Fig. 8, by providing the mesh hole to the gate The edge of the stencil is covered with a shielding plate 75, so that the strength of the slab can be made uniform and a uniform curvature can be easily obtained. The effective area of the ion beam is determined by the shape of the opening of the shielding plate 75, so the opening can be formed to expose only the desired area. The opening of the shielding plate 75 is smaller than the opening of the accelerating electrode 80, so ions are only taken out from the mesh holes exposed by the opening of the shielding plate 75. By using a grid plate and a shielding plate having a hole formed in the outer edge in groups, it is possible to obtain a uniform curvature while suppressing the ion beam from being taken out from the effective area.

The shielding plate 75 is attached to the main body 60 side of the accelerating grid 73, but may be attached to the accelerating grid on the side of the accelerating electrode 80 of the accelerating grid 73. Further, the shielding plate 75 may be formed integrally with the ion gun body 60 instead of other members. An opening is formed in the center portion of the grid bending direction at any position on the grid, so that the curvature of the grid can be integrated at each position in the direction perpendicular to the bending direction. Thereby, compared with the accelerating grid 72 shown in FIG. 7, there is an advantage that the thickness of the accelerating grid 73 can be increased. When the thickness of the grid is thick, the life of the grid can be extended. Further, in the embodiment, a square grid is used, but the hole is formed to the outer edge of the grid plate, and is also effective for a grid of other shapes of a circular shape or an elliptical shape. In particular, when a circular or elliptical grid plate is formed with a hole only in the central portion, although the end portion is bent to use a stronger force, the end portion and the central portion can be eliminated by forming a hole in the end portion. The difference is obtained while obtaining a uniform curvature. Regardless of the shape, it is only necessary to form the mesh holes continuously from one end of the grid to the opposite end, and to bend the grid in a direction perpendicular to the continuously formed grid holes.

Figure 9 is an exploded perspective view showing another embodiment of the grid 70. The accelerating grid 74 is formed in a slit shape by a portion shielded by the shielding plate 75. The effect of obtaining a uniform curvature is the same as that of Fig. 8, but by separating the ion extraction holes and the slits, the boundary between the effective area of the ion beam and the shielding area can be made clear and more easily distinguished.

When the rectangular ion gun 4 shown in Fig. 6 is used, the piezoelectric elements carried in the matrix direction (the direction of the arrow in the same figure) in the order shown in Fig. 10 can be sequentially arranged in units of rows. 200 for frequency adjustment. Fig. 10A is a plan view, and Fig. 10B is a cross-sectional view. The ion gun 4 is disposed such that the long sides are parallel to the row direction with respect to the matrix piezoelectric element 200. The grid 70 of the ion gun 4 is bent in the short side direction. The width in the longitudinal direction of the grid hole group and the width in the short side direction (when the grid shown in Figs. 8 and 9 is used, the width of the opening of the shielding plate 75 and the width of the lateral direction) are only required. The number of rows and columns of the piezoelectric element 200 that is simultaneously adjusted is adjusted. In Fig. 10, a uniform ion beam is irradiated onto all of the piezoelectric elements of one column.

As shown in FIG. 10C, when the grid of the ion gun is a flat surface, the larger the distance d1 between the workpiece to be irradiated (piezoelectric element 200) and the ion gun, the more the ion beam is scattered and the etching rate is lowered. In order to secure the etching rate, the distance d1 between the piezoelectric element 200 and the ion gun 100 must be reduced. However, as the distance becomes smaller, the spatter of the mask 202 and the shutter 201 may accumulate on the ion gun and its periphery and peel off, causing problems such as short circuit between the grids caused by the sputter.

On the other hand, in the ion gun of the present invention, the grid is bent to converge the ion beam, so that the distance d2 between the piezoelectric element 200 and the ion gun 4 can be increased and an equivalent etching rate can be obtained. As the distance d2 is larger, the deposition rate of the sputter to the ion gun body can be reduced, so that the mean time between failures (MTBF: Mean Time Between Failures) can be extended. By charging the ion gun 4 to the frequency adjustment device shown in Figs. 10A and 10B, it is possible to perform frequency adjustment with good reproducibility. Furthermore, by using the grid 70 shown in Figs. 8 and 9, the frequency adjustment accuracy can be improved.

Each of the above embodiments shows the best mode of the present invention, but the above may be changed as follows.

(1) In the above embodiments, the grid 20 is configured as a circular plate or a rectangular plate, but it can be bent and fixed in a single direction along the end surface 11 of the body 10 or the end surface 31 of the acceleration electrode 30. It may be, for example, an ellipse, a square, or the like.

(2) Further, in the present invention, the so-called "frame shape" which exhibits the form of the accelerating electrode also includes at least an outer edge and an inner edge, and the outer or inner edge is circular, elliptical, rectangular, and the like. The shape of the angle and the like.

(3) In the first and fourth embodiments, the fixing tools 40 and 90 are used as means for fixing the accelerating electrodes 30 and 80 and the grids 20 and 70 to the main bodies 10 and 60, but (as shown in the respective figures in the up and down direction) When it is used, the weight of the accelerating electrodes 30 and 80 itself may be increased or a weight or the like may be placed on the upper portion to omit the fixture 40.

(4) In the above-described first, second, and fourth embodiments, the accelerating electrodes 30 and 80 are shown as members for sandwiching the grid 20 between the body 10, but the members are only the accelerating electrodes 30 and 80. If the shape is the same, it may not be an electrode. At this time, as in the case of Fig. 5, it is necessary to directly apply a voltage to the acceleration grid 22.

(5) In the second embodiment, the electrode support is used to maintain the distance between the grids. However, a spacer made of an insulating material or the like may be inserted between the electrodes and fixed.

1, 2, 3, 4. . . Ion gun

10, 60. . . Ontology

11, 61. . . End face

12. . . Electrode support

20, 70. . . Grid

21, 71. . . Shielding grid

22, 72~74. . . Acceleration grid

75. . . Masking board

30, 80. . . Acceleration electrode

31, 81‧‧‧ end face

32, 82‧‧‧ recess

40~44, 90‧‧‧ Fixtures

Fig. 1 is an exploded perspective view showing a first embodiment of the present invention.

Fig. 2A is a side view showing a first embodiment of the present invention.

Fig. 2B is a top view showing the first embodiment of the present invention.

Fig. 3 is a view showing a grid used in the first embodiment of the present invention.

Fig. 4A is a side view showing a second embodiment of the present invention.

Fig. 4B is a side view showing a second embodiment of the present invention.

Fig. 4C is a side view showing a second embodiment of the present invention.

Fig. 5 is a view showing a third embodiment of the present invention.

Fig. 6A is a side view showing a fourth embodiment of the present invention.

Fig. 6B is a front view showing a fourth embodiment of the present invention.

Fig. 6C is a top view showing a fourth embodiment of the present invention.

Fig. 7 is an exploded perspective view showing a fourth embodiment of the present invention.

Fig. 8 is an exploded perspective view showing a fourth embodiment of the present invention.

Fig. 9 is an exploded perspective view showing a fourth embodiment of the present invention.

Fig. 10A is a plan view showing a fourth embodiment of the present invention.

Fig. 10B is a cross-sectional view showing a fourth embodiment of the present invention.

Fig. 10C is a cross-sectional view showing a conventional ion gun.

Fig. 11 is a view showing the configuration of a conventional ion gun.

1. . . Ion gun

10. . . Ontology

20. . . Grid

twenty one. . . Shielding grid

twenty two. . . Acceleration grid

30. . . Acceleration electrode

Claims (10)

An ion gun is provided with an ion gun which generates a plasma inside and a grid for extracting plasma from the inside of the body, and is characterized in that: the grid is clamped on the body a frame-shaped accelerating electrode; the end surface of the body opposite to the grid has a valley-shaped curved surface; the grid is formed to be curved with the surface of the body and the grid A flat grid mounted in a manner that conforms to a curved surface; the grid is planar when manufactured, but when mounted on the body, the end surface of the body is bent in a single direction. The ion gun of claim 1, wherein the ion extraction hole is continuously formed from one end of the grid to the opposite end; the grid is perpendicular to the continuous formed ion extraction hole It is bent in the direction. The ion gun of claim 2, wherein a shielding plate having an opening only in an effective area of the ion beam is mounted on the grid. The ion gun of claim 1, wherein the grid is formed in a square shape. The ion gun according to claim 1, wherein the ion extraction holes of the grid are arranged in parallel in a row direction of the piezoelectric elements arranged in a matrix; The piezoelectric element is irradiated with the ion beam in the column direction in a row unit, and is ion-etched at the resonance frequency of the piezoelectric element. The ion gun of claim 5, wherein the grid is curved in the column direction. An ion gun is provided with an ion gun which generates a plasma inside and a grid for extracting plasma from the inside of the body, and is characterized in that: the grid is clamped on the body a frame-shaped accelerating electrode; the end surface of the accelerating electrode facing the grid has a mountain-like curved surface; the grid is formed to be formed on the adhesion surface between the accelerating electrode and the grid a flat grid supported by the curved surface of the curved surface; the grid is planar when manufactured, but when mounted on the accelerating electrode, the end surface of the accelerating electrode is bent in a single direction . An ion gun is provided with an ion gun which generates a plasma inside and a grid for extracting plasma from the inside of the body, and is characterized in that: the fixed gun is fixed to the body. The end surface of the body opposite to the grid has a valley-shaped curved surface; the grid is formed by a curved surface formed on the adhesion surface of the body and the grid to conform to the curved surface a mounted grid; the grid is flat during manufacture, but when mounted on the body, The end face of the body is bent in a single direction. A grid used in an ion gun according to any one of claims 1 to 7 or 8 which is composed of molybdenum (material) and has a thickness of 200 μm to 20 μm. The grid as described in claim 9 wherein the thickness is from 150 μm to 50 μm.