JPH0920979A - Cathode electrode for magnetron sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure the uniformity of the film thickness distribution of a large- sized substrate having a large area by eliminating the asymmetry of the film thickness distribution and the decrease in the film thickness which arises at the substrate end in a cathode electrode for magnetron sputtering used for film formation on the large-area substrate. SOLUTION: This cathode electrode has a magnet device constituted by lining up at least one piece of magnet units which are magnet units (24) including a central magnet and peripheral magnets and generate tunnel-like magnetic lines of force for forming plasma on the surface of a target 17 in the moving direction thereof and a driving device (motor 34 and mechanism part) which moves this magnet device periodically back and forth. The cathode electrode is so constituted that a magnetic material (a magnetic shunt) 39 for adjusting the magnetic fields by the magnet device and making the discharge generated on the target uniform in at least one points at both ends in the forward and backward moving stage of the magnet device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode electrode for magnetron sputtering, and more particularly to a cathode electrode for a magnetron sputtering apparatus capable of depositing a uniform thin film on the surface of a large substrate having a large processing area.

[0002]

2. Description of the Related Art Heretofore, various types of electrode structures have been proposed for a sputtering apparatus, but among them, the magnetron type electrode structure is most often used industrially. The reason is that the deposition rate is high and the productivity is high. There are various types of conventional magnetron type electrodes, but at present, a flat plate magnetron cathode electrode having a planar shape, for example, a target having a rectangular shape is most industrially useful.

In recent years, it has been particularly demanded to form a film having a uniform area and a uniform film thickness distribution on a rectangular substrate having a large area for manufacturing a liquid crystal display device. Therefore, in the conventional sputtering device, the rectangular cathode electrode is fixed,
A method of forming a film by moving the rectangular substrate while passing it through the front surface of the cathode electrode has been adopted. However, such a device has a load lock chamber, a heating chamber, a buffer space for transportation,
Since it is composed of a sputtering chamber and the like, the apparatus as a whole tends to become huge.

Therefore, in recent years, a sputtering apparatus has begun to be used in which the substrate and the electrode facing the substrate are kept in a stationary positional relationship and the consumption region due to the etching of the target is widened. The structure of this magnetron cathode electrode is a technique in which the uniformity of the film thickness distribution and the uniformity of the etching distribution of the target are improved by reciprocally moving a plurality of magnet units with respect to the target (Japanese Patent Application No. Hei 10 (1999) -135242).
3-194298, Japanese Patent Application Laid-Open No. 5-239640), and similar examples in which a single magnet unit is moved (Japanese Patent Application Laid-Open No. 4-329874).
Japanese Patent Laid-Open No. Hei 5-9724).

[0005]

In the above sputtering apparatus, the uniformity of the film thickness distribution becomes a problem. The size of a substrate used for manufacturing a liquid crystal display device is increasing year by year, and recently, it is about to reach about 500 mm x 600 mm. Uniformity of film thickness distribution (±% value) is defined as (maximum film thickness-minimum film thickness) /
If defined as (maximum film thickness + minimum film thickness) x 100%, in order to use the substrate in the manufacture of liquid crystal display devices, the uniformity of the film thickness distribution within the substrate surface is about ± 5%. Need to

The problem of uniformity of film thickness distribution in the conventional sputtering apparatus will be described in detail with reference to FIG. FIG. 11 shows a vertical cross-sectional structure of a main part of a sputtering device for manufacturing a liquid crystal display device, which is configured by using a magnet device including a single magnet unit. In the figure, the Ar gas introduction mechanism, the vacuum exhaust system, the substrate transfer system, the target water cooling mechanism, the magnet drive mechanism, etc. are omitted, and only the basic configuration of the peripheral portion of the cathode electrode is shown. The rectangular target 101 and the glass substrate 102 are arranged to face each other in the vacuum container 103. Target 1
01 and the substrate 102 have a relatively large area. Around the target 101 and the substrate 102, a part 109 of a vacuum container held at the ground potential is provided.
In particular, a part of the vacuum container 1 is provided around the target 102.
A shield 108 attached to the lower side of 09 is arranged. The target 101 is held at a negative potential by the DC power supply 110. On the back side of the rectangular target 101, a tunnel-shaped annular magnetic field line 10 is formed on the target surface.
A single magnet unit 105 for forming 4 is installed. The magnet unit 105 has a rectangular shape having long sides in a direction perpendicular to the paper surface of FIG. 11, a rod-shaped central magnet is arranged at the center, and an annular peripheral magnet is arranged around the central magnet. The yoke 106 is installed on the back side.
The length of the long side of the magnet unit 105 is substantially the same as the length of the side of the target 105 in the direction perpendicular to FIG.
The surface of the central magnet is magnetized to, for example, the S pole and the surface of the peripheral magnetic pole is magnetized to, for example, the N pole. Also, the magnet unit 105
Are configured to reciprocate in the left-right direction in FIG. 11 by a magnet driving mechanism (not shown), and accordingly, are formed on the surface of the target 101 by the tunnel-shaped magnetic force lines 104, the introduced reaction gas, and the applied voltage. The annular plasma region also reciprocates left and right. By repeating the reciprocating motion of the plasma region, the entire surface of the target 101 can be etched.

Using the above sputtering apparatus, for example, 450 mm
FIG. 12 shows an example of film thickness distribution when a film is formed on a rectangular substrate 102 having a size of x550 mm. Figure 12 shows a film thickness of 400m
It is standardized within the range of m x 500 mm and is expressed by contour lines, and the numbers in the figure represent the percentage of film thickness. As can be seen at a glance, thick portions 107 appear on the upper right and lower left of the substrate 102. Shortening the distance between the target 101 and the substrate 102 further accentuates this asymmetry.

The above-mentioned film thickness distribution appears because the discharge itself is originally biased. The phenomenon of uneven discharge is not due to the asymmetric structure of the film forming chamber. Even if the symmetry of the film forming chamber itself is improved, similar asymmetry occurs in the film thickness distribution. Furthermore, if the polarities of the magnetic poles of the magnet unit 105 installed on the back of the target 101 are reversed (the central magnet is the N pole and the peripheral magnets are the S poles), the bias of the discharge is also changed, and the thick film location is at the upper left. And will appear in the lower right. Therefore, the phenomenon that the discharge is biased is presumed to be related to the drift motion of electrons generated in the plasma generated by the magnetron discharge, but its detailed generation mechanism is unknown.

Further, in the film thickness distribution of FIG. 12, the film thickness distribution uniformity is about ± 10%, which does not satisfy the condition of ± 5% uniformity required for manufacturing a liquid crystal display device. In particular, the film thickness is greatly reduced at the left and right ends of the substrate. FIG.
In the sputtering apparatus shown in (1), the magnet unit 105 is moved to a position close to the end of the target 101 in order to make the etched region of the target as large as possible.
Therefore, the plasma formed along the tunnel-shaped magnetic force lines 104 is attenuated by the ground potential shield 107 existing at the end of the target. As a result, the substrate 10
The phenomenon that the film thickness is reduced occurs at the peripheral portion of 2. In order to prevent this, the magnet unit 105 may be kept away from the shield 108 at the end of the target, but since the area to be etched of the target 101 is reduced and the effective area is also reduced, the film is formed within a predetermined substrate area. Uniformity of thickness distribution cannot be ensured. Further, since a region where etching does not occur occurs around the target 101, a film is deposited at this portion, and this eventually peels off to cause particles. Further, if the area of the target 101 is widened to ensure the uniformity of the film thickness distribution, there is a drawback that the entire apparatus becomes large.

As described above, the problem was pointed out by taking as an example the cathode electrode for a large-sized magnetron sputtering provided with the magnet device including the single magnet unit. This problem is targeted at the magnet device including a plurality of magnet units. On the other hand, a large-sized cathode electrode configured to reciprocate similarly occurs, which is a big problem.

An object of the present invention is to solve the above problems, and in a magnetron sputtering cathode electrode used for a large area substrate, eliminates the asymmetry of the film thickness distribution and the film thickness reduction that occurs at the substrate end, It is to provide a cathode electrode for magnetron sputtering capable of ensuring a uniform film thickness distribution on a large substrate having a large size.

[0012]

The cathode electrode for magnetron sputtering according to the first aspect of the present invention (corresponding to claim 1) comprises a target and a target for achieving the above object.
A magnet device including a magnet unit that includes a central magnet and peripheral magnets and forms a tunnel-shaped magnetic field line on a target; and a drive device (motor and mechanism unit) that periodically reciprocates the magnet device are provided. A magnetic body (magnetic shunt) is arranged at a diagonal position corresponding to each of the two ends of the reciprocating process so as to adjust the magnetic field generated by the magnet device and thereby equalize the discharge generated on the target. .

According to the first aspect of the present invention, when the magnetic body (magnetic shunt) is arranged at a predetermined position, the magnet unit of the magnet device approaches the magnetic body, and preferably becomes a state where they overlap. The magnetic field weakens the magnetic field on the target formed by the magnet unit. In the annular and tunnel-shaped magnetic field on the target, the velocity of electron drift motion increases in the region where the magnetic field is weakened, and the residence time of electrons is shortened, so that the ion density, that is, the plasma density is reduced. As a result, the original tendency of the plasma density to rise in the region can be suppressed, the bias phenomenon of discharge can be eliminated, and a bias-free plasma region can be generated on the upper surface of the target. By creating such plasma generation regions at both ends of the target,
In the thin film formed on the large-area substrate, it is possible to eliminate the occurrence of a thick film portion in the film thickness distribution, which has been a problem in the past, and to make the film thickness distribution uniform.

According to a second aspect of the present invention (corresponding to claim 2), in the first aspect of the invention, the magnet device includes a single magnet unit, and the longitudinal direction of the magnet unit intersects the movement direction of the magnet device. Arranged to do so. Since the number of magnet units is small, the structure is simple.

According to a third aspect of the present invention (corresponding to claim 3), in the second aspect of the invention, a relatively thin yoke that covers the entire lower surface is provided below the magnet unit, and a reciprocating step of the magnet device is performed. A yoke corresponding to half of the magnet unit is provided at a position corresponding to both ends of the magnet unit, and when the magnet unit is located at either end of the reciprocating motion process, the magnetic field outside the magnet unit is strengthened and other movements are performed. In the process, the magnetic fields generated by the magnet units are formed in the same distribution state. This increases the plasma density at the left and right ends of the target. The plasma density thus increased and the plasma attenuation caused by the shield described in the prior art are balanced,
As a result, the plasma density generated over the entire surface of the target can be kept constant without depending on the position of the magnet unit, that is, the magnet assembly in the reciprocating motion. This makes it possible to eliminate the tendency for the film thickness to decrease at the edge of the substrate.

According to a fourth aspect of the present invention (corresponding to claim 4), in the second aspect of the invention, magnets for strengthening a magnetic field outside the magnet unit are provided at positions corresponding to both ends of the reciprocating process of the magnet device. I did it.

According to a fifth aspect of the present invention (corresponding to claim 5), in the first aspect of the invention, the magnet device includes a plurality of magnet units, and each of the magnet units has a longitudinal direction in a direction of movement of the magnet device. They are arranged side by side in the movement direction so as to intersect. By thus increasing the number of magnet units in the magnet device, the area of the plasma region formed on the target can be increased.

According to a sixth aspect of the present invention (corresponding to claim 6), in the fifth aspect, the magnetic pole width of the outer portion of the peripheral magnets of the magnet units located on the outermost sides of the magnet device is changed to the magnetic pole width of the inner portion. And a yoke is provided only on the inner half of the magnet unit, and yokes corresponding to the outer half of the magnet unit are provided at the positions corresponding to both ends of the reciprocating motion process of the magnet device. The magnetic field outside the magnet unit located at the end is strengthened when the magnet device is located at any one of the positions, and the magnetic fields by all the magnet units are configured to be in the same state in the other motion steps.

In the sixth aspect of the present invention, in the magnet device composed of a plurality of magnet units, that is, the magnet assembly is made to reciprocate, the outermost magnet unit is located at the center. When moving near the center of the target compared to the magnet unit, it generates an annular magnetic field on the target that is almost equal to other magnet units, and strengthens the magnetic field outside the annular magnetic field near the left and right ends of the target. I did it. by this,
Increase the plasma density at the left and right edges of the target. This increased plasma density balances the plasma attenuation due to the shield described in the prior art with the result that the entire surface of the target is independent of the position of the magnet unit or magnet assembly in the reciprocating motion. It is possible to keep the density of plasma generated over a constant range. This makes it possible to eliminate the tendency for the film thickness to decrease at the edge of the substrate.

A seventh aspect of the present invention (corresponding to claim 7) is the relatively thin yoke according to the fifth aspect, wherein a plurality of magnet units having the same form are covered with the entire lower surface on the lower side. And a yoke corresponding to the outer half of the outermost magnet unit is provided at a position corresponding to both ends of the reciprocating process of the magnet device, and the magnet device is located at either end of the reciprocating process. At this time, the magnetic field outside the magnet unit located at the end is strengthened, and the magnetic fields by all the magnet units are in the same state in the other motion steps. In the present invention, the same shape is used for the plurality of magnet units. Also, even if a plurality of magnet units have the same shape, a thin yoke is used, and when the magnet device is located at both ends in the process of its reciprocating motion, a portion that strengthens the magnetic force is created based on the above configuration. The same operation as the sixth aspect of the invention described above occurs.

According to an eighth aspect of the present invention (corresponding to claim 8), in the fifth aspect of the invention, a magnet unit disposed outside the magnet device is provided at a position corresponding to both ends of the reciprocating process of the magnet device. It is configured to provide a magnet that enhances the outer magnetic field. The plurality of magnet units have the same structure or different structures.

In the eighth aspect of the present invention as well, basically the sixth aspect of the present invention is used.
The same effect as the invention of When the magnet device, that is, the magnet assembly, reaches the positions of the left and right end portions of the target, the outer magnetic field lines, that is, the magnetic field strength of the outer portion of the magnet unit arranged on the outermost side by the magnets arranged at the end portions and the magnets. It becomes stronger, which increases the plasma density generated at the left and right ends of the target. In the target area other than both ends, all the magnetic fields of the multiple magnet units are substantially equal, so the plasma densities of each part are equal, and a thin film with a uniform film thickness distribution should be formed on a large-area substrate. You can

In a ninth aspect of the present invention (corresponding to claim 9), in the first aspect of the invention, the magnetic body is preferably a soft magnetic body. By using a soft magnetic material, the magnetic field generated in the magnet unit can be weakened.

A tenth aspect of the present invention (corresponding to claim 10) is
In the eighth invention, the soft magnetic material is formed so as to have portions having different thicknesses. By varying the thickness, the degree of weakening the magnetic field can be adjusted.

The eleventh invention (corresponding to claim 11) is
In the first aspect of the present invention, the magnetic body is preferably a magnet.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

1 and 2 show the structure of a first embodiment of a cathode electrode for magnetron sputtering according to the present invention. FIG. 1 is a longitudinal sectional view of a main part, and FIG. 2 is a view of the cathode electrode portion in FIG. 1 as viewed from below. In these figures, an opening 13 is formed in a wall 12 of a vacuum container 11 which forms a processing chamber for processing the surface of a substrate. The wall portion 12 is, for example, a lower wall, and the cathode electrode is installed using the rectangular opening portion 13 formed therein. A cathode body 15 is attached to the opening 13 via an insulating spacer 14. The cathode body 15 has a rectangular tubular shape along the entire circumference of the edge of the opening 13, and
A back plate 16 is attached to the open end of the processing chamber 5 (on the upper side in FIG. 1) so as to cover the opening. The cathode body 15 and the back plate 16 form a part of a wall portion of the vacuum container 11 that forms a processing chamber, and the cathode body 15 and the back plate 16 separate the atmosphere side from the inside of the vacuum container 11.

A target 17 of a predetermined material is adhered to the surface of the back plate 16 with a low melting point brazing material such as indium.
A shield 18 is provided around the target 17 to prevent portions other than the target from being etched. A water cooling jacket 19 for cooling the back plate 16 and the target 17 is provided on the atmosphere side of the back plate 16. In order to uniformly cool the entire back plate 16 inside the water cooling jacket 19, water channels 19 are formed over the entire area.
a is provided, cooling water is introduced from the water introduction pipe 20, and used cooling water is discharged from the water discharge pipe 21. Behind the water cooling jacket 19, a magnet unit 24 including a magnet portion 22 and a yoke 23 is arranged.
The structure of the magnet portion 22 in the magnet unit 24 is the same as that of the conventional magnet unit. That is, it is composed of a central magnet (for example, the surface has an S pole) having a substantially rod shape, and a substantially rectangular annular peripheral magnet (for example, the surface has an N pole) arranged around the central magnet. The long side of the magnet portion 22 is orthogonal to the paper surface of FIG. As shown in FIG. 2, the length of the long side of the magnet unit 24 is the length of the target 17 indicated by the broken line.
The length of the short side of the magnet unit 24 is substantially equal to that of the target unit 17, and the short side of the magnet unit 24 extends along the long side of the target 17.

The magnet unit 24 is fixed on the magnet base 25. The magnet bases 25 are arranged in parallel.
It is constrained by the guide rail 26 of the book and is provided so as to be capable of reciprocating in the left-right direction in FIGS. 1 and 2. In this way, the magnet unit 24 is arranged so that its longitudinal direction is substantially orthogonal to the reciprocating direction. A tip of an arm 27 is rotatably coupled to a magnet base 25 on which the magnet unit 24 is mounted by a coupling pin 28, and a base end of the arm 27 is rotatably coupled to a front end of an upright column 29. Further, the middle part of the arm 27 is rotated by the other arm 30 to rotate the rotating disk 3
Connected to 1. Arms 27 at both ends of arm 30
The connecting pin 32 with and the connecting pin 33 with the rotating disk 31 are rotatable. The rotating disk 31 is attached to the drive shaft of the motor 34. When the rotary disk 31 rotates due to the rotation of the drive shaft of the motor 34, the arm 27 moves in a fan-shaped manner with the support post 29 as a fulcrum as shown by an arrow 35, and the magnet base 25 is swung left and right. A plurality of holes 36 for fixing the coupling pins 33 are provided on the rotating disk 31.
The swinging distance of the magnet base 25 can be changed by changing the mounting position of.

The back surface of the back plate 16, that is, the entire back surface of the cathode electrode is covered with a cathode cover 37. The motor 34 is fixed to the cathode cover 37, and
Is erected on the cathode cover 37. Cathode body 15, back plate 16, target 17, water cooling jacket 19
Are electrically coupled to each other and insulated from other parts, and the parts are supplied with power from an external power supply 38.

In this embodiment, a magnetic shunt 39 made of a soft magnetic material is provided on the back side of the water cooling jacket 19. The magnetic shunt 39 is
As shown in FIG. 3, a soft magnetic material such as SUS 430 is used.
3 thin plates with different shapes (thickness 0.1 m
m) Constructed by stacking 39a, 39b, 39c. The thin plates 39a to 39c are arranged in this order from the side of the water cooling jacket 19 and stacked. The magnetic shunts 39 are attached to the upper right and lower left of the water cooling jacket 19 as shown in FIG. When viewed above the target 17 having a rectangular shape, the two magnetic shunts 39 are arranged at positions at both ends of the diagonal line connecting the upper right corner and the lower left corner.
This mounting position corresponds to the position of the biased discharge that occurs in the conventional cathode electrode for sputtering, that is, the position where the thick film portion 107 is formed in the film thickness distribution on the substrate 102 shown in FIG.

In the magnetic shunt 39 constructed by stacking the thin plates 39a, 39b, 39c, the thickness of each part differs depending on the stacked state of the thin plates. That is, the thickness of the portion where each thin plate exists independently is 0.1 mm, the thickness of the portion where the two thin plates overlap is 0.2 mm, and the thickness of the portion where the three thin plates overlap is 0.3 mm. Three thin plates 39a ~
The portion where 39c is overlapped is the magnetic shunt 39.
The thickest part of the arrow corresponds to the corner of the target 17. This corner corresponds to the location where the film thickness is thickest in the film thickness distribution on the substrate.

According to the present embodiment, by providing the two magnetic shunts 39 at the above-mentioned positions, when the magnet unit 24 reciprocating left and right reaches the mounting position of the magnetic shunt 39, the magnetic field generated from the magnet unit 24 is generated. Can be weakened by the magnetic shunt 39. Therefore, the tunnel-shaped magnetic field generated on the target surface by the magnet unit 24 becomes weak. The ability of the magnetic shunt 39 to weaken the magnetic field of the magnet unit 24 depends on the magnetic shunt 39.
It depends on the thickness of each part. That is, the greater the thickness of the magnetic shunt 39, the greater the degree to which the magnetic field is weakened.

The electric field is E (which is a vector), and the magnetic field is B.
When expressed by (which is a vector), in the magnetron discharge, the electrons make a drift motion of E × B, and the speed of this drift motion is expressed as E / B. Therefore, when the magnetic field B generated by the magnet unit 24 is reduced by the magnetic shunt 39, the velocity of electron drift motion is increased. Therefore, in the region where the magnetic shunt 39 is present, the residence time of electrons is shortened, which reduces the ion density and the plasma density. For this reason, there is a tendency that the plasma density at the location, which originally existed, increases (discharging bias phenomenon).
Can be canceled by the action of the magnetic shunt 39. As a result, a uniform annular plasma is generated on the upper surface of the target 17, and the target 17 can be etched more uniformly by reciprocating the plasma, and the film thickness distribution of the thin film formed on the substrate can be increased. Can be made uniform.

The shape, arrangement position, and thickness of the magnetic shunt 39 are not limited to those described above, and can be appropriately determined according to the state of nonuniformity of the distribution of the thin film formed on the substrate. The configuration of the magnetic shunt 39 is not limited to the configuration in which three thin plates are stacked as described above, and the magnetic shunt 39 may be formed of a single plate material or may be configured by combining other numbers of thin plates. Further, as the magnetic material forming the magnetic shunt 39, any material can be used as long as it can weaken the tunnel-shaped magnetic field generated by the magnet unit 24 to a required degree. For example, a magnet can be used.

In the above embodiment, since the magnet device that reciprocates with respect to the target is made by using the single magnet unit, the structure can be simplified.

FIGS. 4 and 5 show the structure of a second embodiment of the cathode electrode for magnetron sputtering according to the present invention. FIG. 4 is a vertical cross-sectional view of a main part, and FIG. 5 is an external perspective view of a magnet device including a plurality of magnet units. 4 and 5, elements that are substantially the same as the elements described in FIG. 1 are given the same reference numerals.

In the second embodiment, as in the first embodiment, the magnetic shunt 39 is installed in order to obtain a uniform film thickness distribution on the substrate by canceling the bias of the discharge generated on the target. There is. The shape, material, configuration, installation location, etc. of the magnetic shunt 39 are the same as those in the first embodiment.

In the present embodiment, the magnet device further comprises, for example, four magnet units 51, 52. The four magnet units are arranged and fixed on a large magnet base 53 such that their long sides are parallel to each other. An example of the arrangement state is apparent in FIG. 5, which is a perspective view seen from the upper side. In this way, the four magnet units are arranged side by side so that their longitudinal directions are orthogonal to the reciprocating direction. The two magnet units 51 are arranged in the central portion, and the two magnet units 52 are arranged outside of both sides thereof. A structure of a magnet device formed on the magnet base 53 using four magnet units will be referred to as a magnet assembly. The configuration of the two magnet units 51 located at the center among the four magnet units is the same as that of the magnet unit 24 of the first embodiment. That is, the rod-shaped central magnet 51a whose top surface is the S pole, and the central magnet 5
1a and a rectangular ring-shaped peripheral magnet 51b having an N pole on the upper surface, and a peripheral magnet 51b on the lower side.
The rectangular yoke 54 is arranged over the entire surface so as to match the rectangular shape of. The magnet unit 51 has a bilaterally symmetrical shape in its planar shape.

The two magnet units 52 located outside the magnet unit 51 are partially different in shape and configuration. That is, in the magnet unit 52, the central magnet 52a has magnetic poles of the same shape and polarity (S pole), and the peripheral magnet 52b is not symmetrical in plan view, but the width of the long side portion 52b-1 located outside is inward. It has a shape larger than the width of the long side portion 52b-2 located and has a magnetic pole of N pole. Further, the yoke 5 arranged on the lower side
5 is the width of the peripheral magnet 52b (length in the short side direction)
Of the peripheral magnet 52b and the central magnet 52a.

With the above-described form and structure, the magnet unit 52 can generate a tunnel-like magnetic field of uniform strength on the target surface even if no yoke is present in the outer lower half. it can. As a configuration for ensuring the uniformity of the tunnel-shaped magnetic field strength, it is possible to increase the magnetization strength of the magnet on the side where the yoke does not exist while maintaining the same shape. In this embodiment, the magnetic field strengths of the four magnet units 51 and 52 forming the magnet assembly are set to be substantially equal to each other.

The mechanism for reciprocating the entire magnet assembly is different from that of the first embodiment. The magnet base 53 on which the four magnet units are mounted is connected to the rotating disk 31 via the connecting pin 56, the arm 57, and the connecting pin 58. The rotating disk 31 is attached to the drive shaft of the motor 34, and is rotated by the rotation of the drive shaft of the motor 34, so that the magnet assembly (entire magnet unit) is swung left and right. The swing amplitude of this embodiment is smaller than that of the single magnet unit of the first embodiment.

In the present embodiment, further, two fixed yokes 59 made of a soft magnetic material are attached to the cathode body 15 via the support portion 60. This fixed yoke 5
The outermost magnet units 52 on both sides are located just behind the magnet unit at the moment when the magnet units 52 on the outermost sides are closest to the end of the target 17, and are arranged so as to act as a yoke of the magnet unit. However, at this time, a narrow gap is set between the fixed yoke 59 and the magnet portion. With such a configuration, when the outer magnet unit 52 approaches the left and right ends of the target 17, the magnet unit 5
2 increases the magnetic field intensity generated. Moreover, of the magnetic fields generated from the magnet unit 52, the magnetic field strength on the side closer to the target end portion is further increased. Thereby, the plasma density around the end of the target 17 can be increased.

On the other hand, as described in the problems of the prior art,
The phenomenon in which the plasma formed along the tunnel-shaped magnetic field lines is attenuated by the shield 18 existing at the end of the target still exists. Therefore, the factor of increasing the plasma density based on the above-described configuration and the factor of decreasing the plasma density due to the shield 18 are just balanced, and the plasma is irrespective of the position of the magnet unit during rocking. The density is constant. As a result, it is possible to prevent the film thickness from decreasing at the edge of the substrate and form a thin film having a uniform film thickness distribution on the substrate.

Further, in the above embodiment, since the magnet device is constructed by using a plurality of magnet units, plasma is always formed over a wide area on the target surface.
The number of sputtered atoms that are perpendicularly incident on the substrate is overwhelmingly large, which makes the structure of the film deposited on the substrate dense and forms a good quality film.

FIGS. 6 and 7 show the structure of the third embodiment of the cathode electrode for magnetron sputtering according to the present invention. FIG. 6 is a vertical cross-sectional view of a main part, and FIG. 7 is an external perspective view showing a positional relationship between a magnet assembly including a plurality of magnet units and a fixed magnet. In FIGS. 6 and 7, elements that are substantially the same as the elements described in the above figures are given the same reference numerals. The third embodiment is a modification of the second embodiment.

In the present embodiment, four magnet units 61 of the same shape having a symmetrical shape are arranged side by side. The magnet unit 61 has substantially the same structure as the magnet unit 51. Further, two fixed magnets 62 formed of a permanent magnet material are attached to the cathode body 15 via the support portion 60. The shapes and relative positions of the magnet unit 61 and the fixed magnet 62 are clarified by FIG.
Here, even when the position of the magnet unit located outside is closest to the end of the target 17, the fixed magnet 62
It is set so that a narrow gap exists between the magnet unit 61 and the magnet unit 61. The polarity of the fixed magnet 62 is the same as that of the magnet unit 6
It has the same polarity as that of the No. 1 peripheral magnet. Note that, also in the present embodiment, the magnetic shunt 39 for correcting the asymmetry of the film thickness distribution as in the first and second embodiments.
Is installed.

By adopting the above configuration, the tunnel-shaped magnetic field can be formed on the surface of the target 17 only by the fixed magnet 62 during the period when the distance between the outer magnet unit 61 and the fixed magnet 62 is large. Therefore, the magnetron discharge is formed only by the four magnet units 61. On the other hand, as the position of the outer magnet unit 61 approaches the end of the target 17, the width of the peripheral magnets of the outer magnet unit 61 effectively increases.
The magnetic field strength at the end of the target increases. As a result, similarly to the case of the second embodiment, it is possible to compensate for the phenomenon in which the plasma formed along the tunnel-shaped magnetic lines of force is attenuated by the shield 18 existing at the end of the target. Therefore, it is possible to prevent the film thickness from decreasing at the edge portion of the substrate and form a thin film having a uniform film thickness distribution on the substrate. FIG. 8 shows a film thickness distribution of a thin film actually formed by using the cathode electrode for magnetron sputtering according to the present embodiment. It was a conventional problem,
The disadvantages such as the asymmetric distribution and the reduction of the film thickness at the left and right edges of the substrate are solved, and the uniformity of the film thickness distribution is about ± 5%.

In the third embodiment described above, four magnet units 61 of the same shape having a bilaterally symmetrical shape are used, but four magnet units having different shapes as shown in FIG. 5 can also be used.

FIG. 9 shows a fourth embodiment of the cathode electrode for magnetron sputtering according to the present invention, which is the same as the embodiment described in FIGS. 6 and 7 in that the magnet device includes a plurality of magnet units of the same form. This is the same as the embodiment described in FIG. 4 in that fixed yokes are provided at both ends of the reciprocating process. 9, FIG. 6, FIG.
Elements that are substantially the same as the elements indicated by are denoted by the same reference numerals, and detailed description thereof will be omitted. In the present embodiment, the four magnet units 61, all having the same form, have the magnet base 7 having a larger thickness than the magnet base 53 described above.
1 is arranged via a relatively thin yoke 72 having the same form. Each of the four magnet units 61 has the same shape and is arranged on a yoke 72 that covers the entire lower surface thereof. The other configuration is substantially the same as the configuration described in FIG. According to the configuration of this embodiment,
When the motor 34 is operated to reciprocate the entire magnet assembly by the reciprocating mechanism so that either end of the magnet base 71 comes closest to the fixed yoke 59,
The strength of the magnetic field generated by the outermost magnet unit 61 increases under the influence of the fixed yoke 59. Moreover, of the magnetic fields generated from the magnet unit 61, the magnetic field strength on the side closer to the target end portion increases. Thereby, the plasma density around the edge of the target 17 can be increased.

FIG. 10 shows a fifth embodiment of a cathode electrode for magnetron sputtering according to the present invention, which is a modification of the embodiment of FIG. 9 in consideration of the configuration of the embodiment of FIG. 10, elements that are substantially the same as the elements shown in FIGS. 1 and 9 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the present embodiment, one magnet unit 24 includes a magnet base 81 having a relatively large thickness.
Is disposed on the above via a relatively thin yoke 72. Other configurations are substantially the same as the configurations of the embodiment described with reference to FIGS. 1 and 9. According to the configuration of this embodiment, the motor unit 34 is operated, the reciprocating mechanism reciprocates the magnet unit 24, and when the magnet unit 24 is in the closest state to any of the fixed yokes 59, the magnet unit 2
4 and a part of each of the yokes 72 overlap the fixed yoke 59, so that the magnetic field strength generated by the magnet unit 24 increases under the influence of the fixed yoke 59. That is, the magnetic field strength on the side closer to the target end portion is further increased. Thereby, the plasma density around the edge of the target 17 can be increased. In this embodiment, it can be made with a simple structure for construction with a single magnet unit 24.

Further, as shown in FIG. 1 or FIG. 10, in the structure in which the magnet device is provided with a single magnet unit, the magnets 62 as shown in FIGS. 6 and 7 are provided at both ends of the reciprocating magnet device. It is also possible to adopt a configuration in which is provided.

In each of the above-described embodiments, the number of magnet units in the magnet device including the magnet unit arranged below the target is arbitrary and may be one or two or more. The configuration of each magnet unit and the configuration around it are determined according to the purpose, as described in each embodiment. Further, the mounting position of the magnetic shunt configured by using the magnetic material is not limited to the position of the water cooling jacket. It can be attached at any position as long as it exists in a position that achieves the operation described in each embodiment.

[0054]

As is apparent from the above description, according to the present invention, in a cathode electrode of a magnetron sputtering apparatus for forming a thin film on a rectangular substrate having a large area used for a large-sized liquid crystal display apparatus, a target electrode is diagonally aligned. By providing a magnetic body (magnetic shunt) at the position of the target, the magnetic device is provided so as to reciprocate below the target, and the magnetic field at the end of the target surface formed by the magnet unit included in the magnetic device. Since it was configured to adjust to the optimum state, it is necessary to correct the bias of the discharge generated on the target and make the plasma density uniform over the entire surface of the target, and to ensure the uniformity of the film thickness distribution on the large rectangular substrate. You can

Further, since the structure for increasing the strength of the magnetic field generated in the outermost magnet unit when the magnet device arrives at the end of the target is provided, the target is caused by the shield member arranged near the end of the target. It is possible to prevent the plasma density from being attenuated at the edges and further ensure the uniformity of the film thickness distribution of the thin film formed on the large rectangular substrate.

When the magnet device has a single magnet unit, the structure can be simplified as a whole, and when the magnet device is composed of a plurality of magnet units, plasma is always formed over a large area on the target surface. Since the number of sputtered atoms that are vertically incident on the substrate is increased, the film structure becomes dense and a good quality film can be formed on the substrate.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a cathode electrode for magnetron sputtering according to a first embodiment of the present invention.

FIG. 2 is a view of the cathode electrode viewed from the lower side in FIG.

FIG. 3 is a diagram for explaining the configuration of a magnetic shunt.

FIG. 4 is a vertical sectional view of a cathode electrode for magnetron sputtering according to a second embodiment of the present invention.

FIG. 5 is an external perspective view showing a magnet assembly according to a second embodiment.

FIG. 6 is a vertical sectional view of a cathode electrode for magnetron sputtering according to a third embodiment of the present invention.

FIG. 7 is an external perspective view showing a magnet assembly and a fixed magnet of a third embodiment.

FIG. 8 is a diagram showing a film thickness distribution of a thin film formed on a substrate by a magnetron sputtering cathode electrode according to a third embodiment.

FIG. 9 is a vertical sectional view of a cathode electrode for magnetron sputtering according to a fourth embodiment of the present invention.

FIG. 10 is a vertical sectional view of a cathode electrode for magnetron sputtering according to a fifth embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view showing a main structure of a conventional magnetron sputtering apparatus for a large area substrate.

12 is a diagram showing a film thickness distribution of a thin film formed on a substrate by the conventional sputtering device shown in FIG.

[Explanation of reference numerals] 11 vacuum container 15 cathode body 16 back plate 17 target 18 shield 19 water cooling jacket 22 magnet part 23 yoke 25 magnet unit 39 magnetic shunt 51, 52 magnetic unit 51a, 52a central magnet 51b, 52b peripheral magnets 54, 55 Yoke 61 Magnet unit 62 Fixed magnet

Claims (11)

[Claims] 1. A magnetron comprising a target, a magnet device including a magnet unit including a central magnet and a peripheral magnet for forming tunnel-like magnetic force lines on the target, and a drive device for periodically reciprocating the magnet device. In the cathode electrode for sputtering, a magnetic body that adjusts the magnetic field by the magnet device and equalizes the discharge generated on the target is disposed at a position diagonally located at both ends of the reciprocating process of the magnet device. A characteristic cathode electrode for magnetron sputtering. 2. The magnet device according to claim 1, wherein the magnet device includes a single magnet unit, and the magnet unit is arranged such that a longitudinal direction thereof intersects a movement direction of the magnet device. Cathode electrode for magnetron sputtering. 3. A relatively thin yoke is provided on the lower side of the magnet unit so as to cover the entire lower surface of the magnet unit, and a half of the magnet unit is provided at a position corresponding to both ends of the reciprocating process of the magnet device. And a magnetic field outside the magnet unit is strengthened when the magnet unit is located at either of the both ends of the reciprocating motion step, and the magnetic field by the magnet unit is equal in other motion steps. The cathode electrode for magnetron sputtering according to claim 2, which is formed by: 4. The cathode electrode for magnetron sputtering according to claim 2, wherein magnets for strengthening a magnetic field outside the magnet unit are provided at positions corresponding to the both ends of the reciprocating process of the magnet device. . 5. The magnet device includes a plurality of the magnet units, and the magnet units are arranged side by side in the movement direction such that their longitudinal directions intersect the movement direction of the magnet device. The cathode electrode for magnetron sputtering according to claim 1. 6. The magnetic pole width of the outer portion of the peripheral magnets of the magnet units located on both outermost sides of the magnet device is larger than the magnetic pole width of the inner portion, and a yoke is provided only on the inner half of the magnet unit. At the same time, a yoke corresponding to the outer half of the magnet unit is provided at a position corresponding to the both ends of the reciprocating process of the magnet device, and the magnet device is located at either of the both ends of the reciprocating process. At this time, the magnetic field outside the magnet unit located at the end is strengthened, and the magnetic fields by all the magnet units are in the same state in the other motion steps, and the cathode for magnetron sputtering according to claim 5. electrode. 7. A relatively thin yoke that covers the entire lower surface is provided on the lower side of all of the plurality of magnet units, and the outermost portion is provided at a position corresponding to both ends of the reciprocating process of the magnet device. A yoke corresponding to the outer half of the located magnet unit is provided, and when the magnet device is located at either of the both ends of the reciprocating process, the magnetic field outside the magnet unit located at the end is strengthened. The cathode electrode for magnetron sputtering according to claim 5, wherein the magnetic fields of all the magnet units are in the same state in the other motion steps. 8. A magnet for strengthening an outer magnetic field by a magnet unit arranged outside the magnet device is provided at a position corresponding to the both ends of the reciprocating process of the magnet device. 5. The cathode electrode for magnetron sputtering according to item 5. 9. The cathode electrode for magnetron sputtering according to claim 1, wherein the magnetic material is a soft magnetic material. 10. The cathode electrode for magnetron sputtering according to claim 9, wherein the soft magnetic material has portions having different thicknesses. 11. The cathode electrode for magnetron sputtering according to claim 1, wherein the magnetic body is a magnet.