JPH0375369A - Sputtering device - Google Patents

Abstract

PURPOSE:To form a thin film uniform in thickness even if a target is short in the magnetron-type continuous sputtering device by the passage film forming method by providing a means for generating a specified magnetic field to the target. CONSTITUTION:A substrate holder 7 is continuously moved to the right in the figure and transferred to a sputtering chamber 15, and a thin film is formed on the substrates A, B and C successively mounted on the holder 7 while rotating a table 6. In this device, one rectangular target 1 extending orthogonally to the transfer direction is horizontally arranged. A permanent magnet 2 is set on the rear of the target 1 to generate a magnetic field along the target surface and almost orthogonally crossing an electric field in the vicinity of the surface. The magnetic field strength of the magnet on both ends of the target 1 in its longitudinal direction differs from that on the other parts, and the magnetic field on both end regions in the longitudinal direction of the target is strengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering apparatus, and particularly to a sputtering apparatus that continuously performs sputtering to form a thin film on a continuously transferred substrate.

[Prior art]

In recent years, magneto-optical recording media have been widely used for large-capacity data files, etc. as magneto-optical disks that can be written and read using laser light.

The magneto-optical disk has a multilayer structure consisting of a dielectric layer, a recording layer, a protective layer, etc. formed on a transparent substrate such as glass or plastic. For example, the recording layer exhibiting the magneto-optical effect may be a mixed film or a laminated film of a rare earth metal (hereinafter referred to as RE) and a transition metal (hereinafter referred to as TM), and a thin film forming such a thin film may be used. A sputtering method is available as a forming method.

The sputtering method involves introducing an inert gas such as Ar gas into a low-pressure atmosphere to generate a glow discharge, and irradiating a cathode target with ions in the plasma to knock out structural atoms and molecules from the surface of the target material. This is a thin film forming method in which a thin film is deposited on the surface of a substrate on an anode substrate holder placed so as to face the target, and is widely used industrially.

Among the above-mentioned thin film forming methods, the magnetron sputtering method, in which a magnetic field component that is approximately parallel to the target is formed on the target, and the electric field and the magnetic field are made to be substantially orthogonal, has a fast film forming rate and a temperature rise of the substrate to be sputtered. It is widely used in the manufacturing process of semiconductors and magnetic recording media as a very effective thin film forming method.

Next, a conventional manufacturing apparatus for a recording layer of a magneto-optical recording medium will be described.

One type of conventional manufacturing equipment is a magnetron-type sputtering equipment called a rotational film deposition method.The basic structure of this is that a rotating holder is installed in the sputtering chamber above the chamber, and the film is deposited on this holder. Furthermore, in the lower part of the sputtering chamber, two magnetron sputtering cathodes each have a circular target made of RE gold metal 7M metal, which is a film forming material, and a magnetron discharge In order to make this possible, permanent magnets are provided on the back side of each target and are arranged at predetermined intervals.

In the rotary film forming apparatus, the holder provided to face the magnetron sputtering cathode may have a structure that simply revolves, or a structure that rotates around itself (having a planetary gear, etc.). There is. In the case of the revolution type, a film thickness distribution correction plate is arranged to make the film pressure distribution uniform, and in the case of the revolution type, the film thickness distribution can be made uniform even without the film thickness distribution correction plate. .

According to such a rotational film forming type film forming apparatus, the RE
Since the laminated structure of the metal layer and the TM metal layer can be freely changed, a high-quality magneto-optical recording medium with excellent properties such as the amount of magnetization of the recording layer, coercive force, and magneto-optical effect (Kerr effect) can be obtained. It will be done. Further, since the change in the laminated structure of the recording layer can be controlled by the revolution speed or rotation speed of the substrate holder and the sputtering power ratio applied to both targets, the controllability is relatively good.

However, according to the conventional apparatus, in order to achieve film thickness uniformity, it relies heavily on mechanical operating structures such as the film thickness distribution correction plate and the rotation and revolution mechanism, which is not desirable from the viewpoint of cleanliness in the sputtering chamber. Instead, for example, dust caused by sputtered particles adhering to the film thickness distribution correction plate adheres to the substrate on which the thin film is formed, generating pinholes in the thin film.

Moreover, in the above-mentioned rotation-revolution type film forming apparatus, the work of attaching the substrate to the rotation-revolution mechanism is complicated and difficult to automate, resulting in low productivity. In addition, the drive mechanism is complicated and the equipment cost is high, and there are also problems in maintainability.

Furthermore, in the above-mentioned rotating TC film type film forming apparatus, each layer such as a dielectric layer, a protective layer, and a recording layer is formed on the substrate in separate sputtering chambers, so opening of the sputtering chamber is unnecessary. Of course, this is necessary for each sputtering process, and chucking is also required when the substrate holder is transferred between the sputtering chambers and when attached to the rotating shaft within each sputtering chamber. For this reason, there is a problem that the setting time of the substrate holder becomes long and productivity is not improved.

Therefore, in order to improve the productivity, a continuous sputtering apparatus using a passing film forming method as shown in FIG. 5 has been adopted.

The continuous sputtering device using the pass-through film forming method has a plurality of vacuum chambers, each having an independent exhaust system, of which sputtering chambers 126, 127, and 128 are continuously provided.
Then, sputtering is performed continuously. The sputtering chamber 12
6, 127, and 128 are connected and separated by a gate pulp 131. Then, the plurality of substrate holders 121 guided by the transport rolls 120 forming a transport path are
The sputtering chamber 126, 127, 128 is configured to be continuously transported at a constant speed. Further, the substrate holder 121 holds a plurality of plastic substrates 125 arranged horizontally in a direction perpendicular to the direction of transfer thereof.

For example, in the sputtering chamber 127, a magnetron sputtering cathode 122 is placed at the bottom of the sputtering chamber 127 as a film forming material.
E gold metal 7M has a rectangular alloy target 123 extending horizontally and perpendicularly to the substrate conveyance direction, and in order to enable magnetron discharge, there is an alloy target 123 on the back side of the target, as shown in FIG. 6, for example. As shown, the target 123 is arranged so that the two poles have a rectangular annular gap 25 when viewed from above.
It is equipped with a permanent magnet 124 corresponding to the entire area. Also,
A shutter 129 is disposed above the alloy target 123 in order to adjust the film formation time of the film formation layer on the plastic substrate 125.

The alloy target 123 is connected to a target power source 130, which applies sputtering power suitable for the alloy target 123 to form a desired alloy thin film. Further, as described above, the alloy target eye 23 is formed in a rectangular shape that is arranged horizontally and extends in a direction perpendicular to the transfer direction of the substrate holder 121, and the length of the alloy target 123 in the longitudinal direction is usually,
Conventionally, the length has been set to about 1.6 to 2.0 times the total length of the diameters of the plastic substrates 125 arranged in parallel to the substrate holder 121 for practical purposes.

Therefore, in the continuous sputtering apparatus using the passing film forming method, the plurality of plastic substrates 125 arranged in parallel on the substrate holder 121 are continuously transferred and sputtered to form films at the same time, which greatly improves productivity. do.

[Problem to be solved by the invention]

However, in the continuous sputtering apparatus using the pass-through film forming method, the thickness of the thin film formed on the plastic substrate 125 installed at the central portion of the substrate holder 121 in the direction perpendicular to the direction of transport and the thickness of the thin film formed on the plastic substrate 125 installed at the end portions of the substrate holder 121 in the direction perpendicular to the direction of transport are different. There was a difference in the thickness of the thin film formed on the plastic substrate 125. This problem is that the film thickness of the plastic substrates 125 at both ends is smaller than that at the center, which is a problem in which a difference in film thickness occurs depending on the position of the so-called mounting. This is because when the elongated target 123 is used, the film formation rate is extremely low at both ends of the sputtering chamber due to the substrate running line as shown in FIG. A measure was taken to make the longitudinal length of the alloy target 123, which extends horizontally in a direction orthogonal to the transfer direction, sufficiently longer than the width of the substrate running line. However, increasing the length of the alloy target 123 in the longitudinal direction not only increases the size of the sputtering chamber, but also reduces the adhesion efficiency of the target material to the substrate, resulting in an increase in manufacturing costs.

That is, the purpose of the present invention is to solve the above problems,
The present invention provides a sputtering device that can form a high-quality thin film with good productivity and a uniform film thickness distribution without elongating the target in the direction perpendicular to the transport direction.

[Means to solve the problem]

The above object of the present invention is to provide a sputtering apparatus that continuously performs sputtering using a target disposed opposite to the substrate in order to form a thin film on a substrate that is continuously transferred into a sputtering chamber. It is configured as a long rectangular flat plate extending in a direction perpendicular to the transfer direction of the substrate, and is arranged on the back side of the target and extends along the surface so as to be substantially perpendicular to the electric field near the target surface. The magnetic field generating means for forming a magnetic field is provided in a continuous shape corresponding to the entire back surface of the target, and the magnetic field generating means is configured such that the magnetic field is strong at both end regions in the longitudinal direction of the target. This is achieved using a sputtering device with special characteristics.

Embodiments of the present invention will be described in detail below.

[Embodiment]

FIG. 1 shows a schematic view of the main parts of a sputtering apparatus based on the present invention, and FIG. 2 is a schematic plan view showing the positional relationship between a target and a substrate.

As shown in FIGS. 1 and 2, the sputtering apparatus according to the present invention has a plurality of vacuum chambers each having an independent exhaust system 17, among which sputtering chambers 14 and 15 are provided consecutively. At .16, sputtering is performed continuously. The sputtering chambers 14.15.degree. 16 are separated and communicated by a gate valve 18. The plurality of substrate holders 7 guided by the transport rolls 11 forming a transport path are configured to be continuously transported into the sputtering chamber 14, 15, 16 at a constant speed. Furthermore, a rotatable turntable 6 holding circular plastic substrates A, B, and C, respectively, is provided below the main body of the substrate holder 7. The turntable 6 has a rotating shaft 8 at its center, the rotating shaft 8 passing through the main body of the substrate holder 7 and extending upward, and a pinion 9 near the upper end of the rotating shaft 8. is provided.

The pinion 9 engages a rack 10 fixed to the sputtering chamber 14, 15, 16, and the substrate holder 7
By moving along the conveyance rolls 11, the turntables 6 can be rotated in respective predetermined directions.

For example, in the sputtering chamber 15, a magnetron sputtering cathode 3 has a rectangular alloy target 1 made of RE gold metal 7M metal, which is a film forming material, at the bottom to enable magnetron discharge. Therefore, a permanent magnet 2 is arranged on the back side of the alloy target 1.

The alloy target 1 is formed into a single rectangular shape that is horizontally arranged and extends in a direction perpendicular to the direction in which the substrate holder 7 is transferred. A permanent magnet 2 is arranged on the back side of the alloy target 1, and the permanent magnet 2 can form a magnetic field along the surface of the target so as to be substantially perpendicular to the electric field in the vicinity of the surface. The permanent magnet 2 has an elongated rectangular S pole (the magnetic pole is indicated by a diagonal line and a dot in the figure) in the center, and a square annular gap 5 surrounding the S pole. It is constructed as one continuous magnet so that its poles are substantially flush with the outline of the target 1. However, in the Targetera) I, the magnetic field strength of the magnet is different between at least both end portions in the longitudinal direction of the target and the other portions, and for example, as shown in FIG. The structure is divided into three blocks, two end blocks 2a and 2b located on both sides of the central block 2b. The residual magnetic flux density of the magnet of the central block 2b is 0. 7 (T), and on the other hand, the residual magnetic flux density of the magnets at both end blocks 2a and 2c is 1.1 (T).
It is. This causes the permanent magnet 2 to move towards the target l.
The magnetic field at both end regions in the long plane direction becomes stronger.

Therefore, an inert gas such as argon (Ar) gas is introduced from the gas inlet 19 into the sputtering chamber 15 of the sputtering apparatus configured as described above, and sputtering power is appropriately applied to the alloy target 1. Then, the plastic substrates AB and C, on which dielectric layers have been formed in advance, are successively mounted on the substrate holder.

The substrate holder 7 is continuously transferred to the sputtering chamber 15, and a thin film is formed on the plastic substrates A, B, and C while the turntable 6 rotates within the sputtering chamber.

As described above, according to the present invention, the plurality of plastic substrates A, B, and C are held by the substrate holder 7 and sputtered while being continuously transferred, so that productivity can be improved. , the plastic substrates A, B, and C are rotated and transferred within the sputtering chamber 15, respectively. Further, the plasma density on each surface of the alloy target layer 1 during sputtering is higher on the surface portion corresponding to the end blocks 2a and 2c than on the surface portion corresponding to the center block 2b. That is, at both ends of the alloy target 1 in the longitudinal direction, more sputtered particles are scattered upward.

Incidentally, the change in the amount of scattering (evaporation amount) of sputtered particles does not suddenly change at the boundary line between the blocks 2a, 2b, and 2c, but gradually changes. Therefore, the sputtered particles adhering to the plastic substrates A, B, and C can be effectively prevented from increasing when the plastic substrate B is moved to the central position of the sputtering chamber 15 as in the conventional case. Since the same amount of sputtered particles as the plastic substrate B can be attached to the substrates passing through both ends of the sputtering chamber, such as the plastic substrates A and C, the attachment of the plastic substrates reduces the variation in film formation speed depending on the position. is eliminated, the film thickness distribution between the substrates can be made uniform, and of course the uniformity of the film thickness distribution within one substrate is also improved, making it possible to provide a magneto-optical disk with good dynamic characteristics.

In the embodiment described above, the permanent magnet 2 has a structure divided into three blocks, but the device of the present invention is not limited to this, and the device of the present invention may have a structure divided into four or more blocks in order to further gradually change the magnetic properties of the magnet. It may be.

In the embodiment described above, an alloy target made of RE gold and 7M metal was used, but the present invention is not limited to this, and other target materials may be used.

Further, in the embodiment described above, an example was shown in which one plastic substrate is attached to each turntable 6 of the substrate holder 7, and a total of three plastic substrates are mounted and transferred while rotating. The present invention is not limited to this, and it is possible to have more substrates.Also, a sufficient effect can be expected even if a plurality of substrates are attached to a substrate holder and the substrates are transferred while rotating or rotating. It goes without saying that it can be done.

〔Effect of the invention〕

As described above, since the sputtering apparatus of the present invention is configured to continuously perform sputtering to form a thin film on the substrate that is continuously transferred into the sputtering chamber, the sputtering apparatus of the present invention is configured to continuously perform sputtering to form a thin film on the substrate that is continuously transferred into the sputtering chamber. Not only can sputtering be performed continuously, which improves productivity, but in addition to this excellent productivity, the target is a long rectangular flat plate extending perpendicular to the direction of transport of the substrate. The magnets arranged on the back surface side of the target have a continuous shape that corresponds to the entire back surface of the target, and are configured so that the magnetic field is strong at both end regions in the longitudinal direction of the target. The amount of evaporation can be increased, so in order to form a thin film with a uniform thickness on multiple substrates held in a substrate holder, there is no need to increase the size of the target material in the longitudinal direction of the target as in the conventional method. It is possible to avoid differences in film thickness depending on the mounting position on the substrate holder, promote miniaturization of the sputtering chamber, eliminate variations in product quality, and save target material, resulting in extremely high production efficiency. I can do it.

〔Example〕

Hereinafter, the effects of the present invention can be further clarified with reference to Examples.

A sample magneto-optical disk was prepared using the sputtering apparatus of the present invention shown in FIGS. 1 to 3.

The alloy targeter l-1 is placed in the sputtering chamber 15, with a width of 13Q.
nm, length: 600mm, thickness: 5ff111 Tbts Fe7°Co? A material target 1 is arranged horizontally and installed in such a way that its longitudinal direction extends perpendicularly to the transport direction of the substrate. magnet 2
The center is the S pole and the outer periphery is the N pole, and the magnetic field strength in the direction perpendicular to the target surface at a distance of 5 mm from the center of the magnetic pole (N pole) on the target surface is 700 Gauss at the part corresponding to the center block 2b. Yes, 1000 Gauss in the parts corresponding to both end blocks 2a and 2c
Met.

Further, plastic substrates A, B, and C, each having a thickness of 1.2 m and a diameter of 130 mm, are mounted on the substrate holder 7 with a center distance of 150 mm, and the alloy target 1 and the plastic substrates A, B, and C are The vertical distance was 100 m+.

Then, the pressure inside the sputtering chamber 15 was set to 5X10-'T.
After evacuation to orr, 403 CCM of Ar gas was introduced from the gas inlet 19 and the gas pressure was set to 2.0 mTorr.
It was set as r. Next, 2.5kW is applied to the central target 1b.
Apply a discharge power (DC power) of 3. After applying a discharge power (DC power) of OKW to maintain sputter discharge, the substrate holder 7 transports the plastic substrates A, B, and C at a transport speed of 150 ym/min while rotating each of the plastic substrates A, B, and C at 2 rpm. Magnetic films were formed on plastic substrates A, B, and C. FIG. 4 shows the film thickness ratio at the substrate position in the left-right direction (horizontal direction and perpendicular to the substrate transport direction) of the sputtering chamber 15 at this time. Furthermore, after the film formation, Tb2. Fe7゜CoJ! The film thickness of I was measured using a step meter. The results are shown in Table 1.

Table 1 As is clear from Table 1, the variation in film thickness is ±2.0%.
Very good results were obtained.

Next, as a comparison with the above-mentioned Example 1, a conventional sputtering apparatus as shown in FIGS. 5 and 6 was used.

The alloy target 123 is placed in the sputtering chamber 127 with a width of 1
A piece of Tbtx Fe, 27mm, length: 610m, thickness = 5 cm. Co? It is arranged horizontally in a rectangular configuration of material and is installed in such a way that its longitudinal direction extends perpendicularly to the transport direction of the substrate. Also, thickness: 1.2 mm, 1 film = 130 gu plastic substrate A
, B, and C are each mounted on the substrate holder 121 with a center distance of 150 am+, and the vertical distance between the alloy target 123 and the plastic substrates AB, C is 100 am+.
[It was set as 11.]

Then, the pressure inside the sputtering chamber 15 was set to 5X10-'T.
After evacuation to orr, 403 CCM of Ar gas was introduced from the gas inlet 19 and the gas pressure was set to 2.0 mTorr.
It was set as r. Next, 8. Ok
After applying a discharge power (DC power) of W to maintain sputter discharge, the substrate holder 7 rotates each of the plastic substrates A, B, and C at 2 rpm while
The plastic substrates A and B were transferred at a transport speed of 0 trtm/min.

A magnetic film was formed on C. The sputtering chamber 1 at this time
FIG. 7 shows the film thickness ratio at the substrate position of No. 27 in the left-right direction (horizontal direction and perpendicular to the substrate transport direction). Further, after the film formation, Tb23Fe adhered to each of the substrates. Co
The thickness of the 7 films was measured using a step meter. The results are shown in Table 2.

Table 2 As can be seen from Tables 1 and 2 as well as FIGS. 4 and 7, in the conventional case, the variation in film thickness was about ±40%, but in the embodiment of the present invention, the variation was ±40%. Much better results were obtained within 2.0%.

[Brief explanation of drawings]

FIG. 1 is a schematic view of the main parts of a sputtering apparatus based on the present invention, FIG. 2 is a schematic plan view showing the positional relationship between the target and the substrate, FIG. 3 is a plan view showing the magnetic pole shape, and FIG. A distribution diagram showing the relationship between the substrate position in the left-right direction of the sputtering chamber (horizontal direction and perpendicular to the substrate transport direction) and the film thickness ratio in the embodiment of the present invention. Sputtering equipment, Fig. 6 is a plan view showing the magnetic pole shape of a conventional cathode magnet, Fig. 7 is a sputtering chamber horizontal direction in the conventional equipment (horizontal direction perpendicular to the substrate conveyance direction)
FIG. 3 is a distribution diagram showing the relationship between substrate position and film thickness ratio. (Symbols in the figure) 1... Alloy target, 2.20... Permanent magnet, 2a, 2c... Both end blocks, 2b... Center block, 3... Magnetron sputter cathode, 4... Target power supply, 5.25... Gap, 6... Turntable, 7... Substrate holder 8... Rotating shaft, 9...
Pinion, 10...Rack, 11...Transportation roll, 14.15.16...Sputtering chamber, 17...Exhaust system, 18...Gate valve,
19...Gas inlet, 120...Transport roll, 121...Substrate holder,
122... Magnetron sputter cathode, 123
... Alloy target, 124 ... Permanent magnet, 125 ... Plastic substrate, 126, 127.128 ... Sputtering chamber, 12
9...Shutter 130...Sputter power supply, 1
31...Gate valve. (Three idiots) Figure F Figure 擾pus村^ A1 Quantity Cm #I) Procedural amendment flat bottom October 5, 1 year

Claims (1)

[Claims] In order to form a thin film on a substrate that is continuously transferred into a sputtering chamber, a sputtering apparatus that performs continuous sputtering using a target placed opposite to the substrate, in which the target is magnetic field generating means, which is configured as a long rectangular flat plate extending in a direction orthogonal to the target, and is arranged on the back side of the target and forms a magnetic field along the surface of the target so as to be substantially orthogonal to the electric field near the target surface; are provided in a continuous shape corresponding to the entire rear surface of the target, and the magnetic field generating means is configured such that the magnetic field is stronger at both end regions in the longitudinal direction of the target.