JPH11117066A - System and method for sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To almost uniformly progress the erosion of a target by respectively arranging bar-shaped magnets along a pait of edges of a target and executing the arrangement in such a manner that the magnet pole positions of a pair of magnets respectively change along the edges of the target. SOLUTION: Each magnet 10 is arranged along each edge along the longitudinal direction of a target 6, the shape in which, to one end in the longitudinal direction, the other end is twisted by one rotation is formed, and, it is decided that polarity is made different in both edges. Moreover, a pair of magnets 10 are rotated on both sides of the target 6 so as to synchronize around the respective axes by a rotary mechanism 13, by which the direction and strength of the magnetic lines of force continuously and timely change along the longitudinal direction of the target 6. Thus, plasma on the target face is confined, the plasma density increases, and the coating forming rate increases. Moreover, the plasma density on the target face is timely activated, and the ratio of erosion in the target 6 is made approximately uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron sputtering apparatus and a method as one of thin film forming techniques.

[0002]

2. Description of the Related Art Sputtering generally involves generating a plasma by causing a gas discharge in a low-vacuum atmosphere, causing positive ions of the plasma to collide with a target provided on a negative electrode called a cathode, and causing particles sputtered by the collision. Is a method of forming a thin film by adhering to a substrate.
This sputtering method is widely used in the film formation process because the control of the composition and the operation of the apparatus are relatively simple. However, the conventional sputtering method has a disadvantage that the thin film formation rate is lower than that of a vacuum evaporation method or the like.
For this reason, a magnetron sputtering method in which a permanent magnet or an electromagnet is used as a magnetic circuit to form a magnetic field near a target has been devised, thereby increasing the speed of forming a thin film. For mass production. The magnetron sputtering method has a problem in that the film thickness and film quality are non-uniform due to local erosion of the target. To solve this problem, a device for forming a uniform magnetic field perpendicular to the electric field has been devised. Have been.

FIG. 10 shows the structure of a conventional sputtering apparatus. FIG. 11 is a diagram of a sputtering electrode having a magnet on its target surface. 10, 101 is a chamber, 102 is a vacuum pump 120
Vacuum exhaust port of the chamber 101 evacuated by the
Reference numeral 3 denotes a gas introduction pipe to the chamber 101, and 104 denotes a gas flow controller attached to the gas introduction pipe 103. 10
Reference numeral 5 denotes a discharge gas introduced into the chamber 101 from the gas introduction pipe 103, which is usually argon gas. 106 is a target, 107 is a sputtering electrode, 108 is a power source for discharging, 109 is a magnet holder, 110 is a magnet, 11
1 is a substrate holder. Reference numeral 112 denotes a substrate on which a thin film is formed.

The operation of the above-structured sputtering apparatus will be described below. First, the inside of the chamber 101 is evacuated from the vacuum exhaust port 102 to about 10 ⁻⁷ Torr by the vacuum pump 120. next,
Gas inlet tube 10 connected to one end of the chamber 101
Then, the discharge gas 105 is introduced into the chamber 101 through the chamber 3, and the pressure in the chamber 101 is increased to 10 ^-3 to 10 ^-2 Torr.
Keep to the extent. When a negative voltage or a high frequency voltage is applied to the sputtering electrode 107 to which the target 106 is attached by a DC or high frequency sputtering power source 108, the electric field generated by the power source 108 and the magnet holder 1
The plasma generated by the discharge is generated in the vicinity of the surface of the target 106 by the action of the magnetic field of the magnet 110 housed in the substrate 09, a sputtering phenomenon occurs, and the sputtered particles released from the target 106 cause the sputtered particles on the substrate 112 placed on the substrate holder 111. A thin film is formed on the substrate.

[0005]

However, in the above conventional configuration, since the magnetic flux is directed in the same direction over the entire surface of the target, electrons in the plasma receive a force in the same direction over the entire surface of the target. Therefore, the density of electrons in the plasma becomes non-uniform in the target surface. As a result,
There is a problem that the erosion of the target in the direction of the force applied by the electrons progresses rapidly, and the erosion progresses in the reverse direction, and the erosion does not progress uniformly as the erosion progresses. As a result, not only is the material utilization efficiency of the target material extremely poor, but also a problem arises in that the film thickness uniformity of the thin film formed on the substrate surface cannot be ensured. An object of the present invention is to solve the above-mentioned problems and to provide a sputtering apparatus and method capable of causing erosion of a target to proceed substantially uniformly.

[0006]

In order to achieve the above object, the present invention is configured as follows. First of the present invention
According to the aspect, in a sputtering apparatus that performs sputtering using a rectangular target, bar-shaped magnets are respectively arranged along a pair of edges of the target, and the magnetic pole positions of the pair of magnets are aligned along the edge of the target. And a sputtering apparatus characterized in that they are arranged so as to change each other. According to the second aspect of the present invention, the sputtering apparatus according to the first aspect, wherein the pair of magnets are spirally arranged in parallel with each other while maintaining a magnetic pole position where two different magnetic poles face each other. I will provide a. According to a third aspect of the present invention, there is provided the sputtering apparatus according to the first or second aspect, wherein magnetic poles of the pair of magnets are determined so that different poles face each other with a target interposed therebetween.

According to a fourth aspect of the present invention, the sputtering apparatus according to any one of the first to third aspects, further comprising a rotating mechanism for synchronously rotating the pair of magnets around the respective axes at the same speed. I will provide a. According to a fifth aspect of the present invention, there is provided the sputtering apparatus according to any one of the first to fourth aspects, wherein each of the magnets includes a plurality of rod-shaped magnets. According to the sixth aspect of the present invention, using a rectangular target, bar-shaped magnets are respectively arranged along a pair of edges of the target, and the magnetic pole positions of the pair of magnets are respectively set along the edges of the target. In the sputtering method in which the sputtering is performed in a state where the magnets are arranged so as to change, the sputtering is performed while rotating the magnet, and during the sputtering, the direction and density of the magnetic flux are changed with time, and the plasma density on the target surface is changed. Are roughly averaged over time. According to a seventh aspect of the present invention, when rotating the magnet,
A sputtering method according to a sixth aspect, wherein a magnet having two different magnetic poles arranged in a parallel and spiral shape is synchronously rotated at the same speed around each axis.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. (First Embodiment) FIG. 1 shows a structure of a sputtering apparatus for carrying out a sputtering method according to a first embodiment of the present invention. In FIG. 1, 1 is a vacuum chamber, 2 is a vacuum exhaust port provided in the chamber 1 and connected to a vacuum pump 20, 3 is a gas introduction pipe provided in the chamber 1, and 4 is a gas attached to the gas introduction pipe 3. It is a flow controller. Reference numeral 5 denotes a discharge gas introduced into the chamber 1 from the gas introduction pipe 3, which is usually argon gas. Reference numeral 6 denotes a rectangular target arranged at the upper part in the chamber 1, 7 denotes a sputtering electrode for supporting the target 6 attached to the upper surface of the chamber 1 via an insulator 80 on the lower surface, and 8 denotes a negative voltage to the sputtering electrode 7. Or, a direct current or high frequency power source for discharge for applying a high frequency voltage, 9 is a pair of magnet holders arranged in the chamber 1 and arranged along a pair of edges along the longitudinal direction of the target 6, and 10 is a pair of magnets It is a bar-shaped magnet held in the holders 9 and 9 and arranged along a pair of edges of the target 6. Reference numeral 11 denotes a substrate holder arranged in a lower part in the chamber 1 at a position facing the target 6. Reference numeral 12 denotes a substrate held on the upper surface of the substrate holder 11,
A thin film is formed on this substrate.

FIG. 2 is a schematic diagram of a portion of the sputtering apparatus shown in FIG. As shown in FIG. 2, each magnet 10 is disposed outside the target 6 along each edge along the longitudinal direction of the rectangular target 6. Each magnet has a rectangular parallelepiped shape, and has a shape in which the other end is twisted one turn with respect to one end in the longitudinal direction, and the polarity is different at both ends of the magnet 10. That is, in FIG.
The S pole is arranged outside the upper end of the zero, the N pole is arranged inside, and the N pole is arranged outside the lower end and the S pole is arranged inside. On the other hand, in the right magnet 10,
Conversely, the N pole is arranged outside the upper end and the S pole is arranged inside, and the S pole is arranged outside the lower end and the N pole is arranged inside. Therefore, the polarities of the pair of magnets 10 facing each other across the target 6 are determined to be different. 2 and III-III in FIG.
As shown in FIG. 3 which is a cross section, on the upper side of the target 6, the left magnet 10 has an N pole facing the target 6, but the right magnet 10 has a different pole such that the S pole faces the target 6. They face each other with the target 6 interposed therebetween. In the middle part of the target 6, FIGS.
As shown in FIG. 4 which is an IV-IV cross section of FIG. 4, neither the S pole nor the N pole is opposed to the target 6 side of both the magnets 10, and the S pole is located on the upper side of FIG. It is located. Under the target 6 in FIG. 2, as shown in FIG. 2 and FIG. 5 which is a cross-sectional view taken along line VV of FIG. 2, the left magnet 10 has the S pole facing the target 6 but the right magnet 10 has the N magnet. The different poles are opposed to each other with the target 6 interposed therebetween such that the poles face the target 6.

The sputtering apparatus further includes a rotating mechanism 13 having a motor for synchronously rotating the magnets 10 around their respective axes and a control system therefor. Therefore, during the sputtering, the rotating mechanism 13
By rotating the pair of magnets 10, 10 on both sides of the target 6 in synchronization with each other around the respective axes, the direction and intensity of the magnetic force lines 91 change continuously along the longitudinal direction of the target 6, and the time Change.
With the above configuration, the pair of magnets 10, 10
At every point on the target 6 when the magnetic field is rotated synchronously, the strength and direction of the magnetic field change with time. That is, the magnetic field in the III-III section of FIG.
The magnetic field changes continuously as shown in FIG.

In FIG. 2, when the magnetic flux is directed to the right, electrons in the plasma receive a force directed downward in FIG. When the magnetic flux is directed to the left, the electrons in the plasma receive an upward force. Therefore, when the direction of the magnetic flux changes over time, the plasma on the target surface is confined, the density of the plasma can be increased, the erosion rate increases, and the film formation rate on the substrate increases. Further, the plasma density on the target surface is averaged over time, and as shown in FIG. 6, the eroded portion 6a of the target 6 becomes substantially uniform, and the utilization efficiency of the material increases. Note that the synchronous rotation direction of the magnets 10 may be any direction. This is preferable in order to achieve a general average. It is preferable that the pair of magnets 10 rotate at a speed of at least one rotation during the film formation time. Further, each magnet 10 preferably has a higher magnetic flux density generated on the target surface, and preferably has a density of, for example, approximately 100 gauss or more from the viewpoint of the film forming speed. The manner of twisting each magnet is not limited to the one shown in FIG.

(Second Embodiment) FIG. 7 shows a structure of a sputtering electrode of a sputtering apparatus for performing a sputtering method according to a second embodiment of the present invention. The general configuration is the same as that of the first embodiment, except that a pair of magnets 10a, 10a arranged along the edge of the target 6 is cylindrical, and the magnetic poles are arranged spirally. That is. For example, FIG.
In the upper part of the target 6, the left and right magnets 10a,
At the upper end of 10a, the S pole and the N pole oppose each other with the target 6 interposed therebetween. As going down the target 6, the N pole and the S pole oppose each other with the target 6 interposed therebetween, and the S pole and the N pole intersect with the target 6 Are arranged to face each other. Such an arrangement can be configured in this way when magnetizing the magnet. Therefore, as shown in FIG. 7, the magnet 1 is arranged along the edge of the target 6.
Oa and 10a can rotate around their respective axes by a mechanism similar to the rotation mechanism 13 of the first embodiment. That is, during sputtering, the magnetic field on the target surface changes with time from FIG. 8 (A) to (C) via (B), and returns to (A) in one cycle. With the above configuration, the intensity and direction of the magnetic field at all points on the target 6 change with time.

In the second embodiment, the same effect as in the first embodiment can be obtained, and as shown in FIG. 9, the eroded portion 6a of the target 6 in the sputtering method according to the second embodiment is Usage efficiency can be further improved. The rotation directions of the magnets 10a, 10a may be any directions, but the pair of magnets need not necessarily be limited to the same rotation direction. However, it is preferable that the rotational speeds of the pair of magnets 10a and 10a be constant and the rotational speeds of the pair of magnets 10 and 10 be the same in order to substantially average the plasma density over time. Further, each magnet is not limited to a single magnet, and as shown in FIG. 12, a plurality of magnets 10f, 10b, 10
One twisted magnet may be constituted by a combination of c, 10d, and 10e. It is not necessary to rotate each magnet, but it is preferable to rotate each magnet in order to improve the efficiency of using the target. Further, each magnet is not limited to a permanent magnet, and there is no problem even if it is an electromagnet.

[0014]

As described above, according to the present invention, the plasma density on the target surface is substantially uniform, the erosion of the target is substantially uniform, the utilization efficiency of the target material is improved, and the target material is formed on the substrate. This has the advantageous effect that the production rate of the thin film can be improved and uniformity of the film thickness can be ensured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a sputtering apparatus for performing a sputtering method according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a structure near a sputtering electrode of the sputtering apparatus according to the first embodiment.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is a sectional view taken along line VV of FIG. 2;

FIG. 6 is a cross-sectional view illustrating an eroded shape of a target of the sputtering apparatus according to the first embodiment.

FIG. 7 is a schematic diagram showing a structure near a sputtering electrode of a sputtering apparatus for performing a sputtering method according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a time change of a magnetic flux density on a target surface of a sputtering apparatus according to a second embodiment.

FIG. 9 is a cross-sectional view showing the eroded shape of a target of the sputtering apparatus according to the second embodiment.

FIG. 10 is a schematic sectional view showing a conventional sputtering apparatus.

FIG. 11 is a diagram of a conventional sputtering electrode having a magnet on the surface of a target.

FIG. 12 is a schematic view illustrating a structure near a sputtering electrode of a sputtering apparatus according to a modification of the second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Vacuum exhaust port 3 Gas introduction pipe 4 Gas flow controller 5 Discharge gas 6 Target 6a Erosion part 7 Sputtering electrode 8 DC or high frequency power supply 9 Magnet holder 10, 10a Magnet arranged along a pair of edges of target 10b, 10c, 10d, 10e, 10f Plural magnets 11 Substrate holder 12 Substrate 13 Rotation mechanism

Claims (7)

[Claims] 1. A sputtering apparatus for performing sputtering using a rectangular target (6), wherein rod-shaped magnets (10) are respectively arranged along a pair of edges of the target (6), and magnetic poles of the pair of magnets are provided. A sputtering apparatus, wherein the positions are arranged so as to change along the edge of the target. 2. The sputtering apparatus according to claim 1, wherein the pair of magnets (10) are arranged spirally in parallel with each other while maintaining a magnetic pole position where two different magnetic poles face each other. 3. The sputtering apparatus according to claim 1, wherein the magnetic poles of the pair of magnets (10) are determined such that different poles face each other with the target (6) interposed therebetween. 4. A rotation mechanism (13) for synchronously rotating the pair of magnets (10) around their respective axes at the same speed.
The sputtering apparatus according to any one of claims 1 to 3, further comprising: 5. The sputtering apparatus according to claim 1, wherein each of said magnets (10) is constituted by a plurality of rod-shaped magnets. 6. A rod-shaped magnet (1) using a rectangular target (6) along a pair of edges of the target (6).
0) is arranged, and the sputtering is performed in a state where the magnetic pole positions of the pair of magnets are arranged so as to change along the edge of the target, respectively. A sputtering method, wherein the direction and density of magnetic flux are changed with time so that the plasma density on the target surface is substantially averaged over time. 7. The sputtering method according to claim 6, wherein, when the magnet is rotated, magnets having two different magnetic poles arranged in parallel and spirally are synchronously rotated at the same speed around their respective axes. .