JP2010248562A - Magnetron cathode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetron cathode which can form a magnetic field, that is parallel to a substrate and is directed to the center of the substrate, on the substrate by a simple structure while preventing a target member from being eroded non-uniformly and can improve a film thickness distribution. <P>SOLUTION: The magnetron cathode is composed of: a circular target 6 arranged to be opposed to the substrate; and a magnet assembly 15 which is arranged on the back surface of the target to be moved and rotated with respect to the target and is used for generating the non-uniform magnetic field. A central shield part is arranged on the periphery of a central opening of the target and a central cover 10 having a layered structure of a plurality of magnetic components is arranged on the central shield part. A target outer periphery-side holding ring 11 has also the layered structure of the plurality of magnetic components and at least one of the magnetic components induces magnetic anisotropy on the substrate correspondingly to the magnetic field generated by the magnetic assembly. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a magnetron cathode used in a magnetron sputtering apparatus for forming a thin film on a substrate.

  Patent Document 1 aims to form a uniform and uniform magnetic field distribution to form a wide and uniform etching profile of a target, and includes three or more magnetic pole portions, and each magnetic pole portion faces the target. One or a plurality of magnets having the same polarity are provided, adjacent magnetic pole portions have different magnetism toward the target, and one magnetic pole portion is disposed so as to surround the outer periphery of the other magnetic pole portion. A magnetron cathode is disclosed.

  Patent Document 2 aims to improve the usage efficiency of a target. An inner magnet and an outer magnet surrounding the inner magnet with magnetism opposite to that of the inner magnet are yokes made of a plate-like magnetic material. In the cathode for a magnetron sputtering apparatus in which a magnetic circuit configured by magnetic connection is arranged on the back side of the target, between the inner magnet and the outer magnet, at the deepest part of the erosion formed on the target. Disclosing disposing a magnetic field control unit made of a soft magnetic material directed to the main surface side of the yoke via a non-magnetic material member in a region facing directly.

  Patent Document 3 discloses an intermediate position between adjacent magnetron evaporation sources in a magnetron sputtering apparatus in which metal atoms or ions evaporated from a plurality of magnetron evaporation sources provided on the outer periphery of a substrate are attached to the substrate to form a thin film on the substrate. In addition, an auxiliary magnetic pole having the same polarity as that of the outer magnetic pole of the magnetron evaporation source is arranged, and the polarity of the outer magnetic pole of each magnetron evaporation source is all the same, so that the outer magnetic pole of each magnetron evaporation source is A magnetic field repelling near the middle of the auxiliary magnetic pole adjacent to the outer magnetic pole is generated, and a magnetic field line connecting the inner magnetic pole of each magnetron evaporation source and the auxiliary magnetic pole adjacent to the inner magnetic pole is generated. Thereby, a magnetic field having a shape surrounding the substrate is formed, and the adhesion force and the film structure of the film formed on the substrate are improved.

JP 2004-218089 A JP 2005-8917 A JP 2006-118052 A

  As is clear from the above-mentioned cited references, the magnetron sputtering method using a magnetic field can be performed in a vacuum vessel of low pressure and high density plasma, and therefore, the straightness of the sputtered particles can be improved, so there is a step. Since the sputtered particles can be effectively deposited on the part as well, the step coverage is improved. However, in the devices described in Patent Documents 1 to 3, the magnets follow a fixed fixed trajectory. Since it can only move, the position where the sputtered particles are ejected from the metal target member is constant, and it is reduced only by the target member in a certain place. Therefore, there is a problem that the life of the target member is short. The problem is that the distribution is lowered.

  For this reason, in order to prevent the target from being depleted, it is considered to change the region of the target from which the sputtered particles are released by changing the state of the magnetic field, thereby uniformly reducing the target and extending the life of the target. However, in this method, since the magnetic field on the substrate is also nonuniform, there is a problem that it is difficult to construct magnetic anisotropy on the substrate.

  From the above, the present invention forms a magnetic field on the substrate with a simple structure and parallel to the substrate toward the center of the substrate while preventing the target member from being reduced. It is to provide a magnetron cathode that can be provided. Furthermore, in addition to the above-mentioned purpose, in order to prevent the non-uniformity of spattering of the sputtered particles caused by the non-uniformity of the magnetic field, the injection gas injection state in the vicinity of the target is changed to improve the film thickness distribution on the substrate It is an object of the present invention to provide a magnetron cathode.

  Accordingly, the present invention provides an annular target disposed opposite to a substrate disposed in a vacuum vessel, a target outer peripheral holding ring that holds an outer peripheral portion of the target, and a back surface of the target with respect to the target. In the magnetron cathode, which is arranged at least by a magnet assembly that is movable and rotatable and generates a non-uniform magnetic field, a central shield part is provided at the periphery of the central opening of the target, and the central shield part Is provided with a central cover having a laminated structure composed of a plurality of magnetic parts, and the target outer peripheral holding ring has a laminated structure comprising a plurality of magnetic parts, and a plurality of magnetic members constituting the central cover. At least one of a plurality of magnetic parts constituting the body part and the target outer peripheral holding ring But in the inhomogeneous magnetic field due to the magnet assembly are formed corresponding to the magnetic field generated by the magnet assembly to allow build anisotropy on the substrate.

  As a result, at least one shape of the magnetic part constituting the central cover constituting the central shield part and the magnetic part constituting the target outer peripheral holding ring was changed corresponding to the magnetic field generated from the magnet assembly. The passage of magnetic lines of force generated from the magnet assembly can be changed, a parallel magnetic field directed toward the substrate center is generated on the substrate surface, and the magnetic anisotropy in the substrate center direction is formed on the magnetic film laminated on the substrate. It is also possible to add.

  Further, the central shield part is provided with a plurality of central discharge holes that can be opened and closed to discharge the introduced gas in the outer peripheral direction of the central shield part, and the outer shield part provided around the target. And a plurality of outer discharge holes that discharge the introduced gas outwardly of the outer shield part and that can be opened and closed, and a plurality of outer discharge holes that discharge the introduced gas inward of the outer shield part and that can be opened and closed, respectively. It is desirable to form the inner discharge hole.

  As a result, since the injection state of the introduced gas in the vicinity of the target can be changed, the radiation state of the target particles can be changed, and as a result, the dispersion state of the particles emitted from the target can be changed, and the substrate can be evenly distributed. A uniform film thickness distribution can be achieved.

  Further, it is desirable that the central shield part also serves as an electrode, and the central shield part is cleaned by changing the polarity of the electrode by the switching means.

  The magnet assembly is constituted by a plurality of radial magnet groups arranged at a predetermined central angle around the rotation axis, and each radial magnet group is at least one inner peripheral magnet inclined in the central direction. And at least one outer peripheral magnet that is inclined in the outer peripheral direction and has a polarity different from that of the inner peripheral magnet. The number and position of the inner peripheral magnets and the outer peripheral magnets constituting each radial magnet group are the same as the central shield. It is desirable that the portions and the target outer peripheral side holding ring are non-uniformly arranged in accordance with the shape of the holding ring.

  According to the invention of this application, a central discharge port is provided in the central shield part provided at the peripheral edge of the central opening of the target, and the introduced gas is introduced into the outer shield part provided at the peripheral peripheral edge of the target in the inner peripheral direction of the shield part. A plurality of inner discharge holes for discharging the gas and a plurality of outer discharge holes for discharging the introduced gas in the outer peripheral direction of the outer shield part, and further opening and closing them, thereby adjusting the blowing position of the introduced gas blown from these Therefore, since the state of the introduced gas near the target can be changed as desired, the film thickness distribution of the film formed on the substrate can be made uniform.

  In addition, by making the structure of the central cover shape non-uniform, the radiation shape and strength of the magnetic field lines are adjusted, and the shape and structure of the target outer peripheral holding ring are also made non-uniform corresponding to the magnetic field, so that the substrate from the target It is possible to change the distribution of magnetic lines of force in the space leading to. In particular, when magnetic lines of force parallel to the substrate center are formed on the substrate surface, the magnetic thin film can be provided with magnetic anisotropy in the substrate center direction.

  Furthermore, since the polarity of the central shield part can be changed by the switching means, the surface of the central shield part can be cleaned, thereby improving the workability.

It is a schematic block diagram of the magnetron cathode which concerns on this invention. It is a partially expanded schematic view of the magnetron cathode according to the present invention. It is explanatory drawing which showed an example of the magnet arrangement | positioning of the magnetron cathode which concerns on this invention. It is explanatory drawing which showed an example of the center cover of the magnetron cathode which concerns on this invention, (a) is a top view, (b) is a side view. It is explanatory drawing which showed an example of the magnet outer periphery holding ring of the magnetron cathode which concerns on this invention, (a) is a top view, (b) is sectional drawing. It is explanatory drawing which showed examples, such as opening and closing of the outer discharge hole of the magnetron cathode which concerns on this invention, an inner discharge hole, and an electrode side discharge hole.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the magnetron cathode 1 according to the present invention seals an opening 5 of a vacuum vessel 4 that defines a work space (vacuum space) 3 on which a substrate 2 is placed and is attached to the substrate 2. It is fixed to the vacuum vessel 4 so as to face each other. As shown in FIGS. 1 and 2, the magnetron cathode 1 includes an annular target 6 disposed facing the substrate 2, a target that holds the back side of the target 6, and in which cooling water circulates. A holding part 7, a central shield part 40 penetrating through the target holding part 7 and extending to the central opening 8 of the target 6, and a central cover 10 serving also as an electrode for closing the front surface of the central shield part 40; A target outer peripheral holding ring 11 that holds the outer peripheral edge of the target 6, an outer shield part 12 that covers the front surface of the outer peripheral holding ring 11 and is located near the outer periphery of the target 6, the outer shield part 12, and the vacuum A mounting plate 13 disposed between the container 4 and holding the target holding part 7 via an insulating part 14, and the target Provided behind the lifting portion 7, at least constituted by the magnet assembly 15 is freely and movably rotated with respect to the target 6.

  The magnet assembly 15 is provided on a magnet mounting block 16 that is rotatable and movable with respect to the target 6, and a target side plane 16A of the magnet mounting block 16. As shown in FIG. A plurality of radial magnet groups 17 are arranged along the radial direction that are evenly arranged at a predetermined central angle around the rotation axis of the block 16. Each radial magnet group 17 includes at least one inner peripheral magnet 18 inclined in the center direction, and at least one outer peripheral magnet 19 inclined in the outer peripheral direction and having a polarity different from that of the inner peripheral magnet 18. The numbers and positions of the inner and outer magnets 18 and 19 constituting each radial magnet group 17 prevent the generation of non-uniform magnetic fields on the target 6 and the release of sputtered particles from the same location. The targets 6 are arranged unevenly (randomly) to prevent the target 6 from being reduced.

  Further, as shown in FIG. 4 (b), the center cover 10 has a laminated structure composed of a plurality of magnetic parts, and the shape, for example, the size (area), thickness, and shape of each layer 10A to 10D. The magnetic field generated by the magnet assembly 15 is formed so that the non-uniform magnetic field lines generated from the magnet assembly 15 become parallel magnetic fields on the substrate 2. Further, it is desirable that the center cover 10 itself has a non-uniform shape corresponding to the magnetic field.

  Further, as shown in FIG. 5, the target outer peripheral holding ring 11 similarly has a laminated structure made of a magnetic material, and the shape of each layer 11 </ b> A to 11 </ b> D, for example, the size (area), the thickness, and the shape are the same. It is desirable to form it corresponding to the magnetic field generated from the magnet assembly 15. Furthermore, a notch recess 11E may be formed in part.

  As a result, a magnetic field parallel to the thin film formation surface of the substrate 2 formed on the substrate 2 and toward the center of the substrate 2 can be formed, so that magnetic anisotropy parallel to the magnetic thin film and in the central axis direction is realized. It is something that can be done.

  Further, since the polarity of the center cover 10 can be changed by providing the switching mechanism 20 for switching the polarity of the center cover 10, the surface of the center cover 10 can be cleaned.

  In the magnetron cathode 1 according to the present invention, as shown in FIGS. 1, 2, and 6, a plurality of outer gas discharge holes 21 are provided on the outer peripheral side of the outer shield part 12, and a plurality of inner discharges are provided on the inner peripheral side. Holes 23 are provided. Each of the outer gas discharge hole 21 and the inner discharge hole 23 can be opened and closed by a valve 22, and either one can be closed by a closing plug 24. Thus, since the amount and distribution of the introduced gas can be adjusted, the uniformity of the film thickness distribution on the substrate 2 can be improved.

  Further, the central shield part 40 is formed with a plurality of central side discharge holes 30 that are opened at predetermined intervals along the outer periphery of the central shield part 40. It can be closed.

  The valve 22 that opens and closes the inner discharge hole 23 may be electrically controlled. Further, an electrically controllable valve may be provided instead of the closing plug 31 that closes the central discharge hole 30. As a result, the inner discharge hole 23 and the central discharge hole 30 can be controlled from the outside.

DESCRIPTION OF SYMBOLS 1 Magnetron cathode 2 Board | substrate 3 Work space 4 Vacuum container 5 Opening part 6 Target 7 Target holding part 8 Central opening part 10 Center cover 11 Target outer periphery holding ring 12 Outer shield part 13 Mounting plate 14 Insulating part 15 Magnet assembly 16 Magnet mounting block 17 Radial magnet group 18 Inner peripheral magnet 19 Outer peripheral magnet 20 Switching mechanism 21 Outer discharge hole 22 Valve 23 Inner discharge hole 24 Closure plug 30 Central discharge hole 31 Closure plug 40 Central shield part

Claims (3)

An annular target disposed opposite to the substrate disposed in the vacuum vessel, a target outer peripheral holding ring that holds the outer peripheral portion of the target, and a back surface of the target that is movable and rotatable with respect to the target A magnetron cathode arranged at least and constituted by a magnet assembly generating a non-uniform magnetic field,
A central shield part is provided at the periphery of the center opening of the target, and a central cover having a laminated structure of a plurality of magnetic parts is provided on the central shield part.
The target outer peripheral holding ring has a laminated structure composed of a plurality of magnetic parts,
At least one of a plurality of magnetic parts constituting the central cover and a plurality of magnetic parts constituting the target outer peripheral holding ring is configured so that a non-uniform magnetic field generated by the magnet assembly forms magnetic anisotropy on the substrate. A magnetron cathode characterized by being formed so as to correspond to a magnetic field generated by magnet assembly.   The central shield part is provided with a plurality of central discharge holes that can be opened and closed to discharge the introduced gas in the outer circumferential direction of the central shield part, and the outer shield part provided around the target includes: A plurality of outer discharge holes that discharge the introduced gas outwardly of the outer shield part and that can be opened and closed, and a plurality of inner holes that discharge the introduced gas inward of the outer shield part and that can be opened and closed, respectively. The magnetron cathode according to claim 1, wherein a discharge hole is formed. The magnetron cathode according to claim 1 or 2, wherein the central shield portion also serves as an electrode, and the central shield portion is cleaned by changing the polarity of the electrode by a switching means.

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