JP3949473B2 - Sputtering apparatus for disk-shaped substrate, substrate chucking method in the apparatus, and manufacturing method of disk-shaped recording medium using the apparatus - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a sputtering apparatus for forming a thin film on a disk-shaped substrate, and more particularly, when a thin film is formed using the apparatus, the disk-shaped substrate used in the apparatus is chucked. The mechanism relates to a chucking method. The present invention also relates to a method for manufacturing a disk-shaped recording medium, in which a disk-shaped recording medium such as a so-called optical disk is manufactured using the sputtering apparatus.
[0002]
[Prior art]
Recording media manufactured by forming various thin films on a disk-shaped substrate, particularly those having a disk shape, such as CD-based disks such as CD, CD-R, CD-RW, or DVD- There are various disks such as optical disks such as DVD-based disks such as ROM and DVD-R, and magneto-optical disks such as MO and MD. These discs are manufactured by laminating thin films on a substrate made of a material such as polycarbonate by using various methods such as sputtering and spin coating.
[0003]
Generally, a substrate serving as a material for these discs already has a through-hole formed in the central portion at the time of supply. In the subsequent thin film forming process, handling such as carrying in and out of the film forming apparatus or the like and positioning of the substrate in the film forming apparatus or the like is usually performed using this central hole. However, the presence of the central hole may reduce the film thickness or film quality distribution on the substrate during film formation. Therefore, in general, film formation is performed in a state where a cap or the like is placed over the central hole and the influence of the presence on the film formation process is minimized.
[0004]
For example, when manufacturing a DVD-based disk, a thin film made of an ultraviolet curable resin is formed as one of the constituent films by using a spin coating method. Specifically, first, a substrate is mounted on a rotatable table so that the center thereof coincides with the rotation center of the table. For this reason, positioning and fixing the substrate to the table by using a rotating shaft that penetrates the center hole or by placing a cap fixed concentrically to the center of rotation of the table in the center hole of the disk. Is done.
[0005]
Next, the resin is continuously dropped onto the rotating disk from the vicinity of the center hole or from the end of the cap toward the outer periphery of the disk. The dropped resin is diffused by the centrifugal force accompanying the rotation of the disk, and as a result, a resin thin film is formed on the substrate surface.
[0006]
In this case, since the resin must be dropped at a position deviating from the rotation center, a film thickness distribution resulting from this has occurred. However, at present, the red laser light that is generally used for reading a record or the like has a relatively long wavelength, and thus this distribution is within an acceptable range. In the future, in order to further increase the recording density of the optical disk, it is necessary to obtain a thin film with higher uniformity when, for example, blue laser light having a short wavelength is used.
[0007]
Moreover, the metal thin film etc. which are used for a reflecting film etc. are formed using a sputtering method. In this method, the circular substrate is fixed and held on the front surface of the target in the vacuum container in a form in which the central hole portion and the outer peripheral portion thereof are covered with a jig. In general, a certain voltage is applied to the target, whereby a discharge is generated between the target and the substrate, and plasma is generated. A target constituent element on the target surface is sputtered by ions in the plasma, and the sputtered particles adhere to the substrate surface to form a film.
[0008]
At that time, when a substrate fixing jig comes into contact with the substrate surface, abnormal discharge may occur between the thin film and the jig during film formation. This is because the electric charge stored in the thin film or the jig surface by discharge is discharged from the contact point between the shaft and the film surface. Further, when the jig protrudes into the discharge space, the electric field is distorted due to the presence thereof, and as a result, the film thickness distribution may be affected. For this reason, it is preferable that the substrate surface and the jig are always held at a certain minute interval, and if possible, it is preferable not to use the jig itself.
[0009]
The present applicant has proposed a manufacturing process using a substrate that does not have a hole in the center as a means for solving the above problems, that is, as a method for further improving the film thickness distribution in the process using the spin coating method. Yes. When the substrate is used, the number of jigs used for fixing the substrate during sputtering decreases, so that it is easy to maintain a constant distance between the substrate surface and the jig and to reduce abnormal discharge.
[0010]
[Problems to be solved by the invention]
In the sputtering method, in order to maintain a stable and uniform discharge between the target and the substrate, it is preferable that a counter electrode having a ground potential is arranged in parallel to the target surface. Therefore, it is preferable that the substrate holder having the ground potential is disposed to face the target surface, and that the back surface of the substrate is in close contact with the substrate holder surface so as not to disturb the electric field in the discharge space.
[0011]
In addition, the substrate temperature rises due to the incidence of ions or the like or the radiant heat from plasma during normal sputtering. Since polycarbonate used as a substrate material is vulnerable to heat, it is necessary to suppress the rise of the substrate during sputtering. Generally, the temperature rise is suppressed by bringing the back surface of the substrate into close contact with a substrate holder that is cooled with water or the like.
[0012]
However, when there is no central hole in the substrate, it seems difficult to keep the substrate in close contact with the substrate holder by simply fixing only the outer periphery of the substrate. The present invention has been devised to cope with such a case, and provides a chucking method capable of stably bringing a disc-shaped substrate having no central hole into contact with a holder. . The present invention also provides a sputtering apparatus embodying the chucking method and a method for manufacturing a disk-shaped recording medium using the sputtering apparatus.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, a sputtering apparatus according to the present invention is a sputtering apparatus that uses a disk-shaped substrate having a protrusion at the center of the back surface and forms a film on the surface of the substrate in a vacuum vessel. A substrate receiving portion comprising a flat surface closely contacting the substrate and a recess provided in the center of the substrate receiving portion for receiving the protrusion, and a fixing means for fixing and supporting the protrusion is disposed in the recess. It is characterized by.
[0014]
In the sputtering apparatus, the protrusion at the center of the back surface of the substrate has a substantially cylindrical shape that forms part of a cone whose diameter increases as the distance from the back surface of the substrate increases. Preferably it consists of a jar. Furthermore, it is preferable that the sputtering apparatus further includes a mask receiving portion that supports a mask covering the outer periphery of the substrate surface on the outer periphery of the flat surface, and the mask receiving portion supports the mask by a magnetic force.
[0015]
In order to solve the above problems, the chucking method according to the present invention uses a disk-shaped substrate having a substantially cylindrical protrusion at the center of the back surface, and performs sputtering to form a film on the substrate surface in a vacuum vessel. A method for chucking a substrate in an apparatus, comprising:
The protruding portion is inserted into a concave portion having a cylindrical inner surface, and fixed by the fixing means arranged in the concave portion so that the axis of the protruding portion is aligned with the axis of the concave portion, and the protruding portion is inserted in the insertion direction with respect to the concave portion. It is characterized in that the back surface of the substrate is brought into close contact with a flat surface formed around the recess.
[0016]
In the chucking method, the protrusion at the center of the back surface of the substrate has a substantially cylindrical shape that forms a part of a cone whose diameter increases as the distance from the back surface of the substrate increases. It preferably consists of a plunger. Further, in the chucking method, it is preferable that after the back surface of the substrate is brought into close contact with the flat surface, a mask covering the outer periphery of the substrate surface is fixed to the outer periphery of the flat surface by a magnetic force.
[0017]
In order to solve the above problems, a method for manufacturing a disk-shaped recording medium according to the present invention uses a disk-shaped substrate having a substantially cylindrical protrusion at the center of the back surface, and holds the substrate with the protrusion. The projection is inserted into a recess having a cylindrical inner surface provided in the substrate receiving portion, and fixed by the fixing means disposed in the recess so that the axis of the projection coincides with the axis of the recess. Energized toward the insertion direction with respect to the substrate, the back surface of the substrate is brought into close contact with the flat surface that is the substrate receiving portion formed around the recess, the substrate and the mask are directly opposed to the target, and plasma is generated between the substrate surface and the target. A thin film mainly containing a constituent element of the target is formed on the substrate surface by generating and sputtering the target.
[0018]
In this manufacturing method, the protrusion at the center of the back surface of the substrate has a substantially cylindrical shape that forms a part of a cone whose diameter increases as the distance from the back surface of the substrate increases. Preferably it consists of a jar. Further, in the manufacturing method, it is preferable that after the back surface of the substrate is brought into close contact with the flat surface, a mask covering the outer periphery of the substrate surface is fixed to the outer periphery of the flat surface by a magnetic force.
[0019]
【Example】
The substrate chucking method according to the present invention will be described in detail below. Regarding a sputtering apparatus capable of performing the chucking method, a schematic cross-sectional view of a vacuum-side transfer arm having a substrate holder, and an atmosphere side that transfers the substrate to and from the substrate holder substantially facing the vacuum-side transfer arm A schematic cross-sectional view of the transfer arm is shown in FIG. FIG. 2 is a schematic cross-sectional view of a state where the substrate is transferred by these configurations, FIG. 3 is an enlarged view of a portion A in FIG. 2, FIG. 4 is an enlarged view of a B portion, and FIG. The figure which looked at -5 from the board | substrate direction is shown in FIG.
[0020]
The substrate 10 used in the present invention has a protrusion 11 formed at the center of the back surface of the film formation surface. The protrusion has a shape that forms part of a cone whose center is aligned with the center of the substrate and whose diameter increases as the distance from the substrate increases. The substrate holder 21 in the vacuum side transfer arm 20 includes a substrate receiving portion 22 corresponding to the back surface of the substrate and a mask receiving portion 26 disposed on the outer periphery thereof. The substrate receiving part 22 has a substantially circular flat surface and a concave part 23 having a cylindrical inner surface provided at the center thereof.
[0021]
As shown in FIGS. 4 and 5, ball plungers 24 are provided in the recess 23 so as to be driven in a direction perpendicular to the axial center of the cylinder. Has been placed. When the substrate holder 21 holds the substrate 10, the protrusion 11 on the back surface of the substrate is inserted into the recess 23 and fixed and supported by a ball plunger 24 that is a fixing means. At that time, the ball plunger 24 is supported by the action of the urging force of the spring 25 so that the axis of the substrate projection 11 and the axis of the recess 23 coincide.
[0022]
Since the protrusion 11 that comes into contact with the ball plunger 24 has a shape that decreases in diameter as it approaches the back surface of the substrate, the protrusion 11 is pushed inward by the pressing force received from the ball plunger 24 (the insertion direction of the protrusion). Will be pushed toward. By the action of pushing the substrate 10 in this insertion direction, the back surface of the substrate is brought into close contact with and held by a substantially circular flat surface formed as the substrate receiving portion 22. Further, the temperature of the substrate receiving portion 22 is controlled by water cooling or the like, and the temperature of the substrate 10 is also controlled at the same time when the back surface of the substrate is in close contact with the substrate receiving portion 22.
[0023]
The mask 15 has a ring shape, and a mask flange 16 projects from the inner periphery of the mask 15 to cover the outer periphery of the substrate. The mask flange 16 needs to have a width that allows the mask main body 17 and the substrate 11 supporting the mask flange 16 to have a sufficient interval so as not to cause abnormal discharge during film formation by sputtering. Further, in order to minimize the influence on the electric field during film formation, a taper portion is provided at the inner peripheral end portion.
[0024]
Further, the inner peripheral end of the mask flange 16 is spaced from the surface of the substrate 10 with a minute interval equal to or less than a predetermined value in order to prevent the occurrence of abnormal discharge during film formation by sputtering. Need to avoid. For this reason, when the mask 15 is supported by the mask receiving portion 26, the thickness of the mask body 17 and the thickness of the mask flange 16 or the support method of the mask 15 are determined according to the discharge conditions so as to satisfy these requirements. Need to be determined.
[0025]
In this embodiment, the mask 15 is fixed and supported in close contact with the mask receiving portion 26 by a magnet (not shown) positioned in the mask receiving portion 26. For this reason, it is set as the structure which satisfy | fills the above-mentioned requirements by adjusting the thickness of the mask main body 17 and the mask collar part 16. FIG.
[0026]
The atmosphere-side transfer arm 30 has a suction shaft 31 that sucks and holds the substrate at the center of the surface thereof, and a mask holding portion 33 that positions and holds the mask on the surface. Although the suction shaft 31 and the mask holding unit 33 are fixed to the atmosphere-side transfer arm 30, the magnet 35 that applies a magnetic force to the mask 15 and attracts it to the mask holding unit is driven with respect to the atmosphere-side transfer arm 30. It is possible.
[0027]
The operation when the substrate 10 held by the atmosphere-side transfer arm 30 is transferred to the vacuum-side transfer arm 20 will be described below. First, the vacuum-side transfer arm 20 that does not hold the substrate 10 and the mask 15 and the atmosphere-side transfer arm 30 that holds the substrate 10 and the mask 15 at predetermined positions by the suction shaft 31 and the mask holding unit 33 face each other. In this state, the atmosphere-side transfer arm 30 approaches the vacuum-side transfer arm 20 and stops at a predetermined interval. At that time, the substrate protrusion 11 is inserted into the recess 23 of the substrate receiving portion 22 in the vacuum-side transfer arm 20, and the tip thereof is positioned behind the recess than the ball plunger 24.
[0028]
Here, when the holding of the substrate 10 by the suction shaft 31 is released, the urging force of the ball plunger 24 pushes the substrate protruding portion 11 in the insertion direction, and the substrate back surface is in close contact with the flat surface of the substrate receiving portion 22. Fixed and held. Next, the magnet 35 of the atmosphere-side transfer arm 30 is retracted, and the mask 15 can be detached from the mask holding unit 33. In this state, since the magnetic force from a magnet (not shown) in the mask receiving portion 26 has already acted on the mask 15, the mask 15 is attracted and held by the mask receiving portion 26 without changing its posture.
[0029]
Thereafter, the atmosphere-side transfer arm 30 is retracted, and a new target holding unit (not shown) directly faces a predetermined position with respect to the vacuum-side transfer arm 20, and is combined with the vacuum-side transfer arm 20 to form a sputter deposition chamber. Then, a film forming process is executed. After completion of the film formation process, the target holding unit is retracted, and the air-side transfer arm 30 is directly opposed to the vacuum-side transfer arm 20, and the vacuum-side transfer arm 20 is moved in the reverse order to the delivery of the substrate 10 described above. The substrate 10 is transferred to the atmosphere-side transfer arm 30.
[0030]
By adopting the above configuration, even when a substrate having no central hole is used, the substrate holder 21 that is at the ground potential is arranged to face the target surface, and the back surface of the substrate is placed on the substrate holder surface, that is, the surface of the substrate receiving portion 26. It becomes possible to make it adhere. Further, by bringing the back surface of the substrate into close contact with the surface of the substrate receiving portion 26 that is cooled with water or the like, it is possible to suppress the temperature rise of the substrate during sputtering. In addition, the distance between the inner peripheral edge of the mask and the substrate surface can be easily set to a predetermined value, and abnormal discharge or the like can be reduced.
[0031]
In this embodiment, the action direction of the ball plunger 24 is a direction perpendicular to the axis of the recess 23, but the present invention is not limited to this, and it is assumed that it acts in a direction different from the direction of the axis. That's fine. Three ball plungers 24 are arranged for one recess 23, but the number is not limited to three as long as the protrusion 11 can be fixed and supported at the center of the recess. Further, although the ball plunger is used for fixing and holding the protruding portion 11, the configuration is not limited to the ball plunger as long as it has a similar action.
[0032]
Also, instead of simply pushing the substrate in the insertion direction only by the action of the ball plunger, an exhaust port communicating with the recess is provided, and the substrate is transferred when the substrate is transferred from the atmosphere-side transfer arm to the vacuum-side transfer arm in the atmosphere. It is good also as a structure which carries out vacuum suction temporarily. In addition, the protrusion provided on the back surface of the substrate has a shape in which the diameter increases as the distance from the back surface of the substrate increases, and the axial cross section has a trapezoidal shape. The shape is not limited to the above as long as it can adhere to the flat surface of the part. For example, various protrusions that can be fixed by the ball plunger, such as a cylindrical protrusion, or a substantially cylindrical protrusion that is provided with a recess in which the tip of the ball plunger slightly fits the protrusion. Can be used.
[0033]
Further, the present invention is not only used as a manufacturing method of an optical disk etc., but can be applied to a manufacturing process of all disc-shaped members such as a hard disk or the like after a removal process of the central portion. It is.
[0034]
[Effect of the present invention]
By carrying out the present invention, it becomes possible to stably hold a disc-shaped substrate having no central hole in close contact with the holder. As a result, it becomes possible to form a thin film on a disk-shaped substrate having no central hole in a film forming process by a sputtering method as well as a film forming process by a spin coating method. A higher thin film can be obtained. Further, by reducing the number of substrate holding parts in the sputtering method, it is possible to reduce abnormal discharge in the film forming process.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration in a cross section of a vacuum side transfer arm and an atmosphere side transfer arm in a state where the vacuum side transfer arm and an atmosphere side transfer arm are substantially facing each other.
2 is a diagram showing a state when a substrate is delivered between the vacuum side transfer arm and the atmosphere side transfer arm shown in FIG. 1; FIG.
FIG. 3 is an enlarged view showing a part A in FIG. 2;
4 is an enlarged view of a portion B in FIG. 2. FIG.
5 is a view showing a cross section taken along line 5-5 in FIG. 4 as viewed from the substrate side.
[Explanation of symbols]
10: substrate,
11: protrusion,
15: Mask,
16: Mask buttocks,
17: Mask body,
20: Vacuum side transfer arm,
21: substrate holder,
22: Substrate receiving part,
23: recess,
24: Ball plunger,
25: Spring,
26: Mask receiving part,
30: Atmosphere side transfer arm,
31: adsorption axis,
33: Mask holding part,
35: Magnet,

Claims (12)

A sputtering apparatus that uses a disk-shaped substrate having a protrusion at the center of the back surface and forms a film on the surface of the substrate in a vacuum vessel,
A substrate receiving portion comprising a flat surface in close contact with the substrate back surface;
A vacuum-side transfer arm that holds the substrate in the vacuum container , and has a recess provided in the center of the substrate receiving portion, in which the protrusion is accommodated .
In the recess, and the vacuum-side transfer arm securing means comprising a ball plunger for fixing and supporting the projection is Ru is disposed,
An atmosphere-side transfer arm that holds the surface center portion of the substrate and transfers the substrate to the vacuum-side transfer arm;
The protrusion at the center of the back surface of the substrate has a substantially cylindrical shape that constitutes a part of a cone whose diameter increases as the distance from the back surface of the substrate increases.
It said fixing means caused a acts to push against the recess of the protrusion cooperates with the protrusion,
When the atmosphere-side transfer arm delivers the substrate to the vacuum-side transfer arm, the air-side transfer arm is stopped by a predetermined distance from the vacuum-side transfer arm and acts by the cooperation of the fixing means and the protrusion. A sputtering apparatus , wherein the substrate is transferred to the substrate receiving surface by using a substrate . Said ball plunger device of claim 1, wherein that you have disposed equidistantly about an axis of the protrusion. The fixing means further includes an exhaust port communicating with the recess, and takes into account the action of vacuum adsorption when the substrate is transferred from the atmosphere-side transfer arm to the vacuum-side transfer arm. The apparatus according to 1.   4. The apparatus according to claim 1, further comprising a mask receiving portion that supports a mask covering the outer periphery of the substrate surface on the outer periphery of the flat surface, and the mask receiving portion supports the mask by a magnetic force. The device described. A method of chucking the substrate in a sputtering apparatus that uses a disk-shaped substrate having a substantially cylindrical protrusion at the center of the back surface and forms a film on the substrate surface in a vacuum vessel,
The protrusion at the center of the back surface of the substrate has a substantially cylindrical shape that constitutes a part of a cone whose diameter increases as the distance from the back surface of the substrate increases.
Inserting the protrusion into a recess having a cylindrical inner surface;
The atmosphere-side transfer arm that holds the front surface center portion of the substrate is held in a predetermined interval with the vacuum-side transfer arm that holds the substrate from the back side of the substrate in the vacuum container,
In the face-to-face state, the fixing means made of a ball plunger disposed in the concave portion fixes the axial center of the protruding portion so as to coincide with the axial center of the concave portion, and the fixing means and the protruding portion , And urge the protrusion toward the insertion direction with respect to the recess,
A chucking method, wherein the back surface of the substrate is brought into close contact with a flat surface formed around the recess.   The method according to claim 5, wherein the ball plungers are arranged equidistantly about the axis of the protrusion. The fixing means further includes an exhaust port communicating with the recess, and takes into account the action of vacuum adsorption when the substrate is transferred from the atmosphere-side transfer arm to the vacuum-side transfer arm. 5. The method according to 5.   The method according to claim 5, wherein after the back surface of the substrate is brought into close contact with the flat surface, a mask covering the outer periphery of the substrate surface is fixed to the outer periphery of the flat surface by a magnetic force. A method of manufacturing a disk-shaped recording medium,
Using a disk-shaped substrate having a substantially cylindrical projection that forms a part of a cone that is substantially cylindrical in the center of the back surface and increases in diameter as the distance from the back surface of the substrate increases .
The protrusion is inserted into a recess having a cylindrical inner surface provided in a substrate receiving portion for holding the substrate;
The atmosphere-side transfer arm that holds the front surface center portion of the substrate is held in a predetermined interval with the vacuum-side transfer arm that holds the substrate from the back side of the substrate in the vacuum container,
In the face-to-face state, the fixing means made of a ball plunger disposed in the concave portion fixes the axial center of the protruding portion so as to coincide with the axial center of the concave portion, and the fixing means and the protruding portion , And urge the protrusion toward the insertion direction with respect to the recess,
Adhering the back surface of the substrate to a flat surface that is the substrate receiving portion formed around the recess,
Making the substrate and mask face the target;
A disk-shaped recording medium comprising: a thin film mainly comprising constituent elements of the target on the substrate surface by generating plasma between the substrate surface and the target and sputtering the target. Production method. The method of claim 9, wherein said ball plunger characterized that you have disposed equidistantly about an axis of the protrusion. The fixing means further includes an exhaust port communicating with the recess, and takes into account the action of vacuum adsorption when the substrate is transferred from the atmosphere-side transfer arm to the vacuum-side transfer arm. 9. The method according to 9.   The method according to claim 9, wherein after the back surface of the substrate is brought into close contact with the flat surface, a mask covering the outer periphery of the substrate surface is fixed to the outer periphery of the flat surface by a magnetic force.

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