JP2006225713A - Ion-beam sputtering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion-beam sputtering apparatus which prevents a scattered material in a pre-sputtering step from depositing on a substrate to be film-formed. <P>SOLUTION: The ion-beam sputtering apparatus for forming a film on the substrate 22 by sputtering a target 21 fixed on a target holder 15 through irradiating the target with an ion beam 31 projected from a film-forming ion gun 12 and depositing the sputtered particles on the substrate comprises: a rotating mechanism installed on a target holder 15 for the purpose of rolling over the target so that the direction of the surface can be reversed from a film-forming state; a pre-sputtering ion gun 41 arranged so that the irradiation axis can direct the irradiation axis of the film-forming ion gun 12 symmetrically with respect to a rotating shaft 43 of the rotating mechanism; and a shielding plate 42 which surrounds the surface of the reversed target, and prevents the scattering of particles sputtered from the surface of the target of a reversed state by an ion beam 51 projected from the pre-sputtering ion gun 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ion beam sputtering apparatus used for forming a required film on a substrate.

FIG. 5 schematically shows an example of a conventional configuration of this type of ion beam sputtering apparatus. A vacuum is used to attach a film forming ion gun 12 to the wall surface of the vacuum chamber 11 and exhaust the inside of the vacuum chamber 11. A gas introduction pipe 14 for introducing a required gas into the pump 13 and the vacuum chamber 11 is attached.
In the vacuum chamber 11, a target holder 15 and a substrate holder 16 are disposed. In this example, the substrate holder 16 is attached to a rotating shaft 17 and is rotatable about the axis of the rotating shaft 17. In FIG. 5, reference numeral 18 denotes a drive source that rotationally drives the rotary shaft 17.

A target 21, which is a film forming substance, is fixed to the target holder 15, and a substrate (film formation substrate) 22 on which film formation is performed is mounted and fixed to the substrate holder 16. In this example, a shutter 23 is provided near the substrate 22 between the substrate 22 and the target 21, and the shutter 23 is attached to a rotation shaft 24 and can be rotated, that is, can be opened and closed. ing. In FIG. 5, reference numeral 25 denotes a drive source that drives the rotating shaft 24. FIG. 5 shows a state in which the shutter 23 is closed and the surface of the substrate 22 is shielded by the shutter 23.
Film formation on the substrate 22 is performed by rotating the shutter 23 to open the surface of the substrate 22. The vacuum chamber 11 is evacuated by a vacuum pump 13 and then a required inert gas is introduced from a gas introduction pipe 14. The ion beam 31 emitted from the film forming ion gun 12 is applied to the target 21 to sputter the target 21, and the sputtered particles (film forming particles) scattered from the target 21 adhere to the substrate 22 to form a film. In FIG. 5, 32 indicates the scattering direction of the film-forming particles. In film formation, a favorable film thickness distribution can be obtained by rotating the substrate holder 16 and rotating the substrate 22.

By the way, there is a possibility that the surface of the target 21 may be oxidized and further contaminated before being attached to the vacuum chamber 11 or during the opening of the vacuum chamber 11 to the atmosphere when the substrate 22 is detached after the attachment. Therefore, pre-sputtering for removing impurities on the target surface is generally performed as a pretreatment before film formation. This pre-sputtering is performed by irradiating the target 21 with an ion beam 31 from the ion gun 12 for film formation, as in the case of film formation.
As shown in FIG. 5, the shutter 23 is positioned in front of the substrate 22 to shield the surface of the substrate 22 during pre-sputtering, so that sputtered particles (pre-sputtered particles) containing impurities during pre-sputtering are transferred to the substrate. It is made to not adhere to 22.

As described above, the conventional ion beam sputtering apparatus generally employs a configuration in which a shutter is provided between the substrate and the target in order to prevent the pre-sputtered particles from adhering to the substrate on which the film is formed. Various shutter structures have been proposed (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 5-94266

As described above, conventionally, the substrate is shielded by a shutter to prevent pre-sputtering particles containing impurities (spattering substances during pre-sputtering) from adhering to the substrate. The scattering direction is the same as the scattering direction of the sputtered particles (film forming particles) at the time of film formation, that is, the particles are scattered in the direction in which they are efficiently attached to the substrate. It is difficult to completely shield, and it is impossible to completely prevent the pre-sputtered particles from reaching the substrate around the shutter.
In addition, since the film formation region and the pre-sputtering region are the same in the prior art, pre-sputtering particles adhere to the film forming ion gun, and the film forming ion gun is contaminated by the pre-sputtering particles. Maintenance is required, and long-term stable operation of the apparatus is impaired.

  In view of such problems, an object of the present invention is to provide an ion beam sputtering apparatus that can completely prevent pre-sputtered particles from adhering to a film-forming substrate and also prevent adhesion to a film-forming ion gun. There is.

  According to the first aspect of the present invention, there is provided an ion beam sputtering apparatus in which a target fixed to a target holder is irradiated with an ion beam from a film forming ion gun for sputtering, and a film is formed on the substrate with the sputtered particles. The rotation mechanism provided on the target holder and the rotation axis of the rotation mechanism are symmetrical to the irradiation axis of the ion gun for film formation so that the direction of the film can be reversed from the state at the time of film formation. Pre-sputtering ion gun arranged so that the irradiation axis is positioned in the azimuth and the above-mentioned inverted target surface, and the inverted target surface is irradiated with an ion beam from the pre-sputtering ion gun and sputtered And a shielding plate that prevents scattering of the light.

In the invention of claim 2, in the invention of claim 1, when the target holder fixes the two targets facing each other and one target is reversed from the state during film formation, the other target is in the state during film formation. It becomes a double-sided fixed type.
According to a third aspect of the present invention, in the first or second aspect of the present invention, when the rotating mechanism rotates on the shielding plate, the retraction mechanism is retracted, and after the completion of the rotating operation, the movement is brought into close contact with the inverted periphery of the target surface. A mechanism is provided.

According to the present invention, by adopting the above-described configuration, it is possible to completely prevent the scattering material (pre-sputtered particles) from adhering to the film formation substrate during pre-sputtering, thereby performing high-quality film formation. be able to.
In addition, since the deposition ion gun does not become dirty due to the adhesion of the pre-sputtered particles, the maintenance cycle of the deposition ion gun is extended, and the deposition and stable operation can be performed for a long time.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 schematically shows a configuration of an embodiment of an ion beam sputtering apparatus according to the present invention, and portions corresponding to those in FIG.
In this example, a rotation mechanism is provided in the target holder 15, and a pre-sputtering ion gun 41 is provided separately from the film forming ion gun 12, and a shielding plate 42 is further provided.
The rotation mechanism of the target holder 15 allows the direction of the surface (target surface) 21a of the target 21 to be reversed from the state during film formation facing the substrate 22 and directed in the opposite direction. In FIG. 1, reference numeral 43 denotes a rotation shaft, and the target holder 15 can be rotated around the axis of the rotation shaft 43. In this example, the target holder 15 is a double-sided fixed type, and the two targets 21 can be fixed to each other on both the upper and lower surfaces as shown in FIG.

In the target holder 15 having the above structure, when the target holder 15 is rotated by 180 ° and one of the targets 21 is inverted from the state at the time of film formation, the other target 21 is in the state at the time of film formation. It is said.
The pre-sputtering ion gun 41 is attached to the wall surface of the vacuum chamber 11 at a position facing the film forming ion gun 12 with the target holder 15 interposed therebetween, and the irradiation axis of the pre-sputtering ion gun 41 is relative to the rotating shaft 43. The film is positioned in a direction symmetrical to the irradiation axis of the ion gun 12 for film. In FIG. 1, reference numeral 51 denotes an ion beam emitted from the pre-sputtering ion gun 41.

In this example, the shielding plate 42 includes a cylindrical fixed portion 44 and a moving mechanism 45 that is housed and disposed at one end side (upper end side) of the fixed portion 44 so as to be movable (movable in and out). It is assumed to be cylindrical.
The shielding plate 42 is positioned on the lower surface side of the target holder 15, that is, positioned on the opposite side of the substrate 22 with the target holder 15 interposed therebetween, and the fixing portion 44 is fixed and attached to the wall surface of the vacuum chamber 11.
FIG. 1 shows a state in which the upper end of the moving mechanism 45 is moved toward the target holder 15 and the upper end of the moving mechanism 45 is in close contact with the peripheral edge of the surface of the target 21 located on the lower surface side of the target holder 15. The target 21 positioned on the lower surface side of the target holder 15 is surrounded by the shielding plate 42, that is, the surface 21 b is surrounded, that is, the lower surface of the target holder 15 is separated into a space 46 partitioned by the shielding plate 42 and the wall surface of the vacuum chamber 11. The surface 21b of the target 21 located on the side faces. With respect to this space 46, the ion beam emission side end of the pre-sputtering ion gun 41 is positioned in the space 46 as shown in FIG. 1.

In the ion beam sputtering apparatus having the above-described configuration, film formation on the substrate 22 is performed in the same manner as the conventional ion beam sputtering apparatus shown in FIG. 5, that is, the ion beam 31 is transferred from the film forming ion gun 12 to the target holder 15. This is performed by irradiating and sputtering the target 21 located on the upper surface of the substrate.
On the other hand, in the pre-sputtering, the target holder 15 is rotated to turn the surface of the target 21 to be pre-sputtered in the direction opposite to that during film formation, and the ion beam 51 is applied to the target 21 from the pre-sputtering ion gun 41. This is done by irradiating. In FIG. 1, 52 indicates the scattering direction of the pre-sputtered particles scattered from the target 21 during the pre-sputtering, and the scattering direction 52 of the pre-sputtered particles is a direction opposite to the scattering direction 32 of the film-forming particles in this example. .

Thus, in this example, the ion gun 41 dedicated to pre-sputtering is provided separately from the ion gun 12 for film formation, and the target 21 is reversed to perform pre-sputtering. Contrary to the scattering direction 52 of the particles, the pre-sputtered particles are most difficult to reach the substrate 22 even if there is a wraparound phenomenon with respect to the substrate 22 arranged so that the film-forming particles adhere efficiently. ing.
In addition, when the pre-sputtering is performed, the moving mechanism 45 of the shielding plate 42 is brought into close contact with the peripheral edge of the surface of the target 21 so that the scattering of the pre-sputtered particles can be completely blocked (blocked) by the shielding plate 42. Therefore, according to this example, the adhesion of the pre-sputtered particles to the substrate 22 can be eliminated.

Further, scattering of the pre-sputtered particles is prevented, that is, the pre-sputtered particles are confined in the space 46 sealed by the shielding plate 42, so that the pre-sputtered particles adhere and the film forming ion gun 12 becomes dirty as in the prior art. Therefore, the maintenance cycle of the film forming ion gun 12 can be prolonged, and the film forming process can be stably operated. Since the pre-sputtering ion gun 41 is dedicated to pre-sputtering, a relatively small and inexpensive one can be used.
By the way, there is a case where the vacuum chamber 11 is opened between the film forming steps in order to replace the other target 21 while the target 21 in use, that is, the eroded target 21 is fixed to the target holder 15. In such a case, the surface of the target 21 where the erosion has progressed is oxidized by being released into the atmosphere, so that the surface must be cleaned again by pre-sputtering before the next film formation. In this case, if a surface shape different from the surface shape due to erosion of the target surface by the previous film formation is formed by pre-sputtering, the scattering density distribution of the sputtered particles changes, and the film formation conditions change and the film thickness distribution changes. The reproducibility and stability of film thickness control are impaired, and continuous film formation with high accuracy cannot be performed.

In this example, in order to avoid such a problem, the surface shape by erosion at the time of film formation of the target 21 and the surface shape by erosion at the time of pre-sputtering are matched. FIG. 2 shows this state.
The irradiation axis of the film forming ion gun 12 and the irradiation axis of the pre-sputtering ion gun 41 are positioned on the same straight line passing through the rotating shaft 43 as shown in FIG. The incident angle of the beam 31 and the position where the irradiation axis as the density center of the ion beam intersects the target surface, the incident angle of the ion beam 51 with respect to the surface 21b of the target 21 during pre-sputtering, and the irradiation as the density center of the ion beam The position where the axis intersects the target surface is the same. Further, for example, by selecting the distance L1 between the ion gun 12 for film formation and the target surface 21a, the distance L2 between the ion gun 41 for pre-sputtering and the target surface 21b, and the spread angles θ1 and θ2 of the ion beams 31 and 51, The erosion region 47 of the surface 21a and the erosion region 47 'of the target surface 21b are made the same.

  Thereby, as illustrated in FIG. 2, the surface shape formed by erosion at the time of film formation of the target 21 can be made the same as the surface shape formed by erosion at the time of pre-sputtering. The reproducibility of the film thickness distribution during film formation can be ensured, and the film thickness control can be stabilized. In the example of FIG. 2, the irradiation axes of both the film forming ion gun 12 and the pre-sputtering ion gun 41 are shown in a straight line passing through the rotation shaft 43. However, these two irradiation axes are not necessarily straight. It does not have to be aligned on the line. That is, the irradiation axis of the pre-sputtering ion gun 41 is set in a direction symmetrical to the irradiation axis of the film forming ion gun 12 with respect to the rotation axis 43, that is, the film forming ion gun 12 is rotated around the rotation axis 43 (with the target 21). ) It should be arranged in alignment with the orientation obtained by inversion.

FIG. 3 shows the operation of the moving mechanism 45 of the shielding plate 42. In FIG. 3, the arrow 61 indicates the rotation direction of the target holder 15, and the arrow 62 rotates the target holder 15 to which the target 21 is fixed. The moving direction of the moving mechanism 45 when rotating around the moving shaft 43 is shown.
As shown in FIG. 3, the movement of the moving mechanism 45 in the direction of the arrow 62 enables the target holder 15 to rotate. Note that after the rotation operation is completed, the moving mechanism 45 is returned to the original position, and is brought into close contact with the peripheral edge of the surface of the target 21 located on the lower surface of the target holder 15.

In this example, the shielding plate 42 that performs such an operation ensures a high shielding property of the space 46, that is, a pre-sputtering region and a film forming region that are independent from each other are secured in one vacuum chamber 11. In addition, since the target holder 15 is a double-sided fixed type and can fix the two targets 21 so as to face each other, it is possible to perform pre-sputtering of another target 21 simultaneously during the film forming process. it can.
Therefore, for example, in the case of forming an alternately laminated multilayer film in which different types of films are repeatedly stacked, if it is desired to perform pre-sputtering at the beginning of the formation of each layer, the pre-sputtering can be performed during the formation of the other film. Therefore, the process time can be shortened accordingly, and film formation can be performed very efficiently. In addition, since the surface shape due to erosion during film formation of the target 21 and the surface shape due to erosion during pre-sputtering are matched as described above, high reproducibility, high controllability, and high stability are ensured. Such a multilayer film can be formed with extremely high accuracy.

FIG. 4 shows an example in which the rotation direction of the target holder 15 and the arrangement position of the pre-sputtering ion gun 41 are changed with respect to the configuration shown in FIGS.
In this example, the target holder 15 rotates about the axis of the rotation shaft 43 arranged in a direction orthogonal to the rotation shaft 43 in FIG. 1, and the irradiation axis of the pre-sputtering ion gun 41 rotates. It arrange | positions in the position as shown in FIG. 4 so that it may be located in the azimuth | direction symmetrical with the irradiation axis of the ion gun 12 for film-forming with respect to the moving axis 43.
In such a configuration, as in the case shown in FIG. 2, the incident angles of the ion beams 31 and 51 with respect to the target surfaces 21a and 21b can be made the same, and the erosion regions 47 and 47 'can be made the same. The surface shape formed by erosion at the time of film formation of the target 21 and the surface shape formed by erosion at the time of pre-sputtering can be made the same as shown in FIG.

The schematic diagram which shows one Example of the ion beam sputtering device by this invention. The figure for demonstrating the arrangement | positioning relationship between the ion gun for film-forming, and the ion gun for pre-sputtering, and the erosion of a target. The figure for demonstrating operation | movement of a shielding board. A is a figure for demonstrating the other example of arrangement | positioning relationship of the ion gun for film-forming, and the ion gun for pre-sputtering, B is the side view which abbreviate | omitted one part. The schematic diagram which shows the structure of the conventional ion beam sputtering apparatus.

Claims (3)

In an ion beam sputtering apparatus in which a target fixed to a target holder is irradiated with an ion beam from a film forming ion gun for sputtering, and a film is formed on the substrate by the sputtered particles.
A rotation mechanism provided in the target holder to enable the orientation of the target surface to be reversed from the state during the film formation;
A pre-sputtering ion gun arranged so that the irradiation axis is positioned in a direction symmetrical to the irradiation axis of the film-forming ion gun with respect to the rotation axis of the rotation mechanism;
An ion that surrounds the inverted target surface and includes a shielding plate that prevents the sputtered particles from scattering when the inverted target surface is irradiated with an ion beam from the pre-sputtering ion gun. Beam sputtering equipment. The ion beam sputtering apparatus according to claim 1.
The target holder is a double-sided fixed type in which two targets are fixed with their backs facing each other, and when one of the targets is reversed from the state during film formation, the other target is in the state during film formation. A characteristic ion beam sputtering apparatus. In the ion beam sputtering apparatus according to claim 1 or 2,
The ion is characterized in that the shielding mechanism is provided with a moving mechanism that retracts when the rotating mechanism rotates, and contacts the periphery of the inverted target surface after the rotating operation is completed. Beam sputtering equipment.

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