Patent Application
20160002769
The present invention relates to a PVD processing apparatus and PVD processing method.
With a view to enhancing wear and abrasion resistance of a cutting tool and enhancing sliding properties of a sliding surface of a mechanical component, a substrate (article) to be formed as a cutting tool or a mechanical component is subjected to coating formation, specifically, formation of a coating such as TiN, TiAlN or CrN, through a physical vapor deposition (PVD) process. As an apparatus for use in such coating formation known is a PVD processing apparatus including an arc ion plating (AIP) apparatus and a sputtering apparatus.
As such a PVD processing apparatus, there has been known a type of forming a composite coating by a combination of a plurality of different PVD processes. For example, there has been known a type of forming a hard coating on a surface of a substrate (article) by an arc ion plating process and then forming a lubricating coating on the hard coating by a sputtering device. Thus alternately using a plurality of types of PVD processes enables a composite coating to be formed on the surface of the substrate.
For example, the following Patent Literature 1 discloses a PVD processing apparatus which comprises: a chamber containing therein both of a sputtering vaporization source and a vacuum arc vaporization source; a substrate holder; and a shutter for shuttering, during use of one of the two vaporization sources, the other vaporization source, wherein a plurality of types of coatings on a substrate can be formed by sequential restriction of the use of the two vaporization sources or simultaneous use of the two vaporization sources. In this PVD processing apparatus, the two vaporization sources are arranged such that respective targets of the vaporization sources are oriented in the same direction. The substrate holder holds the substrate at such a position that the substrate is spaced apart from each of the targets of the vaporization sources by a constant distance and rotates the substrate. The rotated substrate can be displaced from a position in front of one of the targets to a position in front of the other target, thereby allowing coating formation to be performed in front of each of the targets alternately to form a composite coating.
The Patent Literature 2 discloses a PVD processing apparatus which comprises: a vacuum chamber containing therein both of a sputtering vaporization source and a vacuum arc vaporization source; and a cylindrical jig provided inside the vacuum chamber, the jig having a peripheral surface on which a substrate is mounted. In this apparatus, the revolution (rotation) of the jig allows the two vaporization sources to be sequentially used, thereby enabling a plurality of types of thin coatings to be formed on the surface of the substrate.
According to the PVD processing apparatuses disclosed in the Patent Literatures 1 and 2, it is possible to form a coating having a uniform thickness if the subject of the coating formation be a flat-plate-shaped substrate, but it is difficult to form a coating on an outer peripheral surface of a cylindrical-shaped member, such as a drill or a tip. That is because the coating formation on the outer peripheral surface of the cylindrical-shaped member requires the member, i.e., the substrate, to rotate on its own axis, but the PVD processing apparatus disclosed in either of the Patent Literatures 1 and 2 is provided with no mechanism for rotating the substrate. That is why the PVD processing apparatus disclosed in either of the Patent Literatures 1 and 2 is incapable of adequate coating formation on such a member as mentioned above.
Even the above PVD processing apparatus, however, could perform the above composite coating on the thus shaped substrate if being modified, for example, not only to revolve but also to rotate the substrate on its own axis during the coating formation. For example, the above composite coating would be enabled to be formed on the substrate by: providing a revolving table capable of revolution around a revolution axis in a vacuum chamber; providing a rotating table capable of rotating about its axis parallel to the revolution axis on the revolving table; placing a substrate on the rotating table to make the substrate revolve and rotate on its own axis; and providing a plurality of different types of vaporization sources radially outside the revolving table.
However, even in the case of revolving and rotating a substrate by use of a mechanism with the above-mentioned revolving and rotating function, there can remain a problem of failing to obtain a homogeneous composite coating if a rotation ratio (gear ratio) of the rotating of the rotating table to the revolution of the revolving table is not set to an adequate value. For example, setting the rotation ratio of the rotating table to the revolving table to an adequate value enables a composite coating having a cross-sectional shape with a plurality of concentrically laminated circular ring-shaped coating layers, whereas, failing to set the rotation ratio of the rotating table to the revolving table to an adequate value may cause a composite coating with an inhomogeneous structure to be formed. Specifically, it generates a possibility that such a C-shaped coating that a circumferentially part of a circular ring is lacking is included in a composite coating, or a possibility of causing some circular ring-shaped coating layers only respective circumferential part of which overlap each other.
It is an object of the present invention to provide a PVD processing apparatus and a PVD processing method capable of forming a good composite coating on an outer peripheral surface of a substrate through the rotation and the revolution of the substrate.
Provided by the present invention is a PVD processing apparatus for performing coating formation on respective surfaces of a plurality of substrates, the PVD processing apparatus comprising: a vacuum chamber containing therein the plurality of substrates; a revolving table provided in the vacuum chamber and configured to support the plurality of substrates and to revolve the supported substrates around a revolution axis; a plurality of rotating tables configured to support respective substrates of the plurality of substrates and rotating the supported substrates, on the revolving table, about their respective rotation axes parallel to the revolution axis; a plurality of targets formed of respective different types of coating-formation materials, the targets disposed at respective positions circumferentially spaced on radial outside of the revolving table; and a table rotating mechanism for rotating each of the rotating tables about its rotation axis in synchronization with the rotation of the revolving table. The table rotating mechanism is configured to rotate the rotating table, on which the substrate is placed, about its rotation axis by an angle of 180° or more relatively to the revolving table, while the substrate passes through a region between two tangent lines drawn from a center of each of the targets to an arc enveloping the rotating tables.
Also provided is a PVD processing method for coating formation on respective surfaces of a plurality of substrates, the PVD processing method comprising: preparing a vacuum chamber containing therein the plurality of substrates, a revolving table provided in the vacuum chamber and configured to support the plurality of substrates and to revolve the supported substrates around an revolution axis, and a plurality of targets formed of respective different types of coating-formation materials, the targets disposed at respective positions circumferentially spaced on radial outside of the revolving table; and performing PVD processing involving rotating each of the substrates about its rotation axis by an angle of 180° or more relatively to the revolving table while the substrate passes through a region between two tangent lines drawn from a center of each of the targets to an arc enveloping each of the substrates.
With reference to the drawings, there will be described a PVD processing apparatus 1 according to an embodiment of the present invention. The PVD processing apparatus 1 according to the embodiment is designed to perform formation of composite coating on a surface of a substrate W by use of two or more types of PVD processes or by alternate or simultaneous use of two or more types of targets in the same type of PVD process. In the PVD processing apparatus 1 according to the below-described embodiment, performed is formation of a composite coating by use of both of arc ion plating process and sputtering process included in various PVD processes.
As shown in
Each of the rotating tables 4 is a disk-shaped member with an outer diameter less than an outer diameter of the revolving table 3, having an upper surface allowing the substrate W to be placed thereon. Each of the rotating tables 4 is driven by the table rotating mechanism 6 so as to rotate about its rotation axis 8 parallel to the revolution axis 7. The substrate W to be placed on each of the rotating tables 4 is an article having an outer peripheral surface circularly curved along a circumferential direction thereof, such as a drill or a tip, the curved outer peripheral surface allowing a coating to be formed thereon. The substrate W in this embodiment is a cylindrical-shaped article; however, the substrate which is subject of coating formation according to the present invention is not limited to a cylindrical-shaped one. For example, the term “substrate” herein includes a conical-shaped member with a sharp-pointed tip, and a substrate assembly including a plurality of disk-shaped members stacked to form a cylindrical contour as a whole.
Each of the targets 5 is made of a material serving as a raw material for a coating, such as Ti, Al, Ni and C, formed into a plate shape in this embodiment. The plurality of targets 5 include a target for arc ion plating and a target for sputtering, being formed of respective different types of coating-formation materials. The target 51 for arc ion plating and the target 52 for sputtering are disposed at respective positions spaced circumferentially of the revolving table 3 on radial outside of the revolving table 3. In the graphically shown example, the target 52 for sputtering is disposed on one lateral side of the revolving table 3 (on the upper side in the drawing sheet of
The table rotating mechanism 6 distributes a rotational driving force generated by a non-shown drive motor to the revolving table 3 and the rotating tables 4, thereby rotating the two types of tables 3, 4 at a given gear ratio.
The PVD processing apparatus 1 shown in
Specifically, each of the table rotating mechanisms 6, 16 includes a central gear 9 provided on the revolving-table-3 side, and a plurality of rotating gears 10 provided on respective rotating-table-4 sides. The central gear 9 and each of the rotating gears 10 are meshed with each other in the circumferential arrangement of the rotating gears 10 around the central gear 9. As shown in
The table rotating mechanism 6 is given a gear ratio of the central gear 9 to each of the rotating gears 10 such that each of the rotating table 4 on which the substrate W is placed rotates about its rotation axis by an angle of 180° or more relatively to the revolving table 3, while each of the substrates W passes through the region between two tangent lines L1, L2 drawn from a center of each of the targets 5, namely, each of the targets 51, 52, more specifically, a widthwise center of one of opposite surfaces of the target facing the revolving table 3, the widthwise center being a center with respect to a direction perpendicular to the revolution axis, to an arc enveloping the rotating tables 4, preferably, an arc 13 enveloping the outer peripheral surfaces of the substrates W supported by the respective rotating tables 4, as shown in
The central gear 9 according to this embodiment is disposed under the revolving table 3 and fixed to a table base other than the revolving table 3 so as to permit the revolving table 3 to rotate relatively to the central gear 9. The central gear 9 has teeth arrangement around the revolution axis 7. The rotating gears 10 are arranged around the central gear 9 while meshed with the central gear 9. Each of the rotating gears 10 are supported by the revolving table 3 so as to be rotatable integrally with the respective rotating tables 4 about their respective rotation axes 8. The revolving table 3 is driven to be rotated by the aforementioned drive motor, involving the rotational drive of each of the rotating tables 4 coupled to the central gear 9 via the respective rotating gears about their respective rotation axes 8. In other words, each of the revolving table 3 and the rotating tables 4 are rotated wherein each of the rotating gears 10 is applied with the rotational driving force from the not-graphically-shown drive motor to be thereby moved along an outer periphery of the central gear 9 by use of the applied rotational driving force.
For PVD processing of a plurality of substrates W by use of the PVD processing apparatus 1 with the configuration shown in
The table rotating mechanism 6, meanwhile, rotates the substrates W and the rotating tables 4 supporting the substrates W, respectively, about their respective rotation axes by an angle of 180° or more, relatively to the revolving table 3, while each of the substrates W passes through the region between the two tangent lines L1, L2 drawn from the center of each of the plurality of targets 5, namely, the targets 51, 52 in this embodiment, to the arc 13 enveloping the rotating tables 4. The reason why such a rotation angle should be set will be described with reference to the PVD processing apparatus 1 shown in
From a center of an electrode surface of the target 52 for sputtering, a coating-formation material is scattered while spreading in a spray-like pattern, toward the revolving table 3 (toward the revolution-axis-7 side). More specifically, the coating-formation material spattered from the target 52 for sputtering is scattered so as to spread in a fan-like or sector shape, in a direction from the center of the electrode surface to the revolving table 3, as shown in
Below will be described about the case of no rotation of each of the rotating tables 4 as shown in
Even in the region between the two tangent lines L1, L2, a specific part of the outer peripheral surface of the substrate W can be hidden from the target 52 for sputtering behind the substrate W itself until the specific part reaches the position Pa, which prevents any coating from being formed on the surface of the specific part.
The rotation of the revolving table 3 causes the revolution of the substrate W, the revolution changing the relative position of the substrate W to each of the targets 5 on a horizontal plane. Thus, the substrate W provided on the revolving table 3 has a changing position in an absolute coordinate system relatively to each of the targets 5, even when the substrate W makes no rotation on its axis, which causes also a position where the coating-formation material will be deposited on the outer peripheral surface of the substrate W to be varied on the outer peripheral surface.
For example, the deposition of the coating-formation material can be discussed with a focus on a specific point on the outer peripheral surface of the substrate W, as follows. The rotation of the revolving table 3 moves the specific point indicated by the mark in
As described above, no rotation of each of the substrates W generates no possibility of covering the entire outer peripheral surface of the substrate W even with the combination of the coating on the blacked-out region A1 and the coating on the outlined region A2 shown in
In contrast, the rotation of each of the rotating tables 4 on its axis by a sufficient angle, as shown in
For example, in the case where the point indicated by the mark in
Although the above embodiment uses the target 52 for sputtering to form a circumferentially seamless continuous coating, operating the table rotating mechanism 6 so as to satisfy the aforementioned relationship with the target 51 for arc ion plating also makes it possible to form a circumferentially seamless continuous coating, that is, a composite coating having a homogenous structure, on the outer peripheral surface of the substrate W.
However, even when a seamless continuous coating can be formed over the entire circumference of the outer peripheral surface of the substrate W, there remains possibility of partial overlap of an initially-formed coating layer and a lastly-formed coating layer in a composite coating, as shown in
Against this, it is preferable to set the gear ratio which allows the rotating table 4 on which the substrate W is placed to rotate by an angle of 360° or more, preferably, an angle of 720° or more, relatively to the revolving table 3 while each of the substrates W passes through the region between the two tangent lines L1, L2. This suppresses the unevenness in coating thickness to allow a composite coating with a more homogenous structure to be formed. Specifically, regarding the rotation angle that is an angle by which the rotating table 4 rotates relatively to the revolving table 3 while the substrate W passes through the region between the two tangent lines L1, L2, the rotation angle of 180° permits about ±50% of a variation in coating thickness to occur, whereas the rotation angle of 360° reduces the variation to about ±30%, and, furthermore, the rotation angle of 720° reduces the variation to about ±10%.
Next will be described effects of the PVD processing method of the present invention, more specifically, based on an inventive example and a comparative example.
There is used in experiments a PVD processing apparatus 1 shown in
A target 51 is used for the arc ion plating process, the target 51 being a circular plate with a diameter of 100 mm and disposed at a position radially outward away from an outer peripheral edge of the revolving table 3 by a distance DT of 160 mm. Coating formation is performed through supply of an arc current of 150 A to the target 51 for arc ion plating and supply of nitrogen gas into a processing space in a vacuum chamber 2 until the pressure in the processing space reaches 3 Pa.
In the inventive and comparative examples, a central gear 9 is provided for the revolving table 3 while a rotating gear 9 is provided for each of the rotating table 4, and the gear ratio of the rotating gear 10 of the central gear 9 in the inventive example is different from that of the comparable example. These gear ratios are presented in Table 1. In the table rotating mechanism 6 in the inventive example shown in
In the above inventive and comparative examples, measured is a thickness of a coating formed on a surface of the substrate W while the substrate W revolves over 180° from the position P1 to the position P2 in
As shown in
This shows that rotating each of the rotating tables 4 by an angle of 180° or more relatively to the revolving table 3 while each of the substrates W passes through the region between the two tangent lines L1, L2 makes it possible to form a seamless continuous coating over the entire circumference of the outer peripheral surface of the substrate W to thereby form a composite coating having an excellent coating thickness uniformity, on the outer peripheral surface of the substrate W.
It should be noted that the present invention is not limited to the above embodiment and examples, but various changes and modifications may be made therein in terms of shape, structure, material, combination, etc., of each component, without departing from the spirit and scope of the invention hereinafter defined. Further, as regards matters which are not explicitly disclosed in the above embodiment, such as operating and processing conditions, various parameters, and size, weight and volume of each component, any value easily assumable to a person having ordinary skill in the art may be employed without departing from a range usually implemented by a persons skilled in the art.
As above, the present invention provides a PVD processing apparatus and a PVD processing method capable of forming a good composite coating on an outer peripheral surface of a substrate through the rotation and revolution of the substrate.
Provided by the present invention is a PVD processing apparatus for performing coating formation on respective surfaces of a plurality of substrates, the PVD processing apparatus comprising: a vacuum chamber containing therein the plurality of substrates; a revolving table provided in the vacuum chamber and configured to support the plurality of substrates and to revolve the supported substrates around a revolution axis; a plurality of rotating tables configured to support respective substrates of the plurality of substrates and rotating the supported substrates, on the revolving table, about their respective rotation axes parallel to the revolution axis; a plurality of targets formed of respective different types of coating-formation materials, the targets disposed at respective positions circumferentially spaced on radial outside of the revolving table; and a table rotating mechanism for rotating each of the rotating tables about its rotation axis. The table rotating mechanism is configured to rotate the rotating table, on which the substrate is placed, about its rotation axis by an angle of 180° or more relatively to the revolving table while the substrate passes through a region between two tangent lines drawn from a center of each of the targets to an arc enveloping the rotating tables.
Also provided is a PVD processing method for performing coating formation on respective surfaces of a plurality of substrates, the PVD processing method comprising: preparing a vacuum chamber containing therein the plurality of substrates, a revolving table provided in the vacuum chamber and configured to support the plurality of substrates and to revolve the supported substrates around an revolution axis, and a plurality of targets formed of respective different types of coating-formation materials, the targets disposed at respective positions circumferentially spaced on radial outside of the revolving table; and performing PVD processing involving rotating each of the substrates about its rotation axis by an angle of 180° or more relatively to the revolving table while the substrate passes through a region between two tangent lines drawn from a center of each of the targets to an arc enveloping each of the substrates.
According to the above PVD processing apparatus and method, the rotation of the substrate on its axis by an angle of 180° or more relatively to the revolving table while the substrate passes through the region between the two tangent lines allows a coating having excellent uniformity to be formed on the outer peripheral surface of the substrate. This allows a composite coating having an excellent coating thickness uniformity to be formed on the outer peripheral surface of the substrate.
For example, it is preferable that the table rotating mechanism of the PVD processing apparatus includes: a central gear having teeth arrangement around the revolution axis, the central gear fixed so as to permit the revolving table to rotate relatively to the central gear; and a plurality of rotating gears configured to rotate integrally with the respective rotating tables about their respective rotation axes, the rotating gears being arranged around the central gear while meshed with the central gear so as to allow the rotating gears to rotate on their respective rotation axes in synchronization with the rotation of the revolving table about the revolution axis. In this case, it is more preferable to set a gear ratio of the central gear to each of the rotating gears such that the rotating table on which the substrate is placed rotates on its rotation axis by an angle of 180° or more relatively to the revolving table while the substrate passes through a region between the two tangent lines.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-056771 | Mar 2013 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/001143 | 3/3/2014 | WO | 00 |
