JP3898318B2 - Sputtering equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetron sputtering equipment, which is one of the thin-film forming technique.
[0002]
[Prior art]
The sputtering method generally generates a plasma by causing a gas discharge in a low vacuum atmosphere, collides the cation of the plasma with a target installed on a negative electrode called a cathode, and the particles sputtered by the collision adhere to the substrate. This is a method for producing a thin film. This sputtering method is widely used in the film formation process because the composition control and the operation of the apparatus are relatively simple.
[0003]
However, the conventional sputtering method has a drawback that the thin film formation rate is slower than the vacuum deposition method or the like. For this reason, a magnetron sputtering method has been devised that uses a permanent magnet or an electromagnet as a magnetic circuit to form a magnetic field in the vicinity of the target, thereby improving the formation rate of the thin film, and by the sputtering method in the manufacturing process of semiconductor components and electronic components. Mass production of thin film formation has become possible.
[0004]
FIG. 18 is a sectional view showing a schematic configuration of an example of a conventional magnetron sputtering apparatus. 18, 101 is a chamber, 102 is a vacuum exhaust port of the chamber 101 evacuated by a vacuum pump (not shown), 103 is a gas introduction pipe to the chamber 101, and 104 is a gas flow rate attached to the gas introduction pipe 103. It is a controller. A discharge gas 105 is introduced into the chamber 101 from the gas introduction tube 103, and argon gas is usually used. 106 is a target, 107 is a sputtering electrode, 108 is a power source for discharge, and 110 is a magnet disposed on the back surface of the target 106. Reference numeral 111 denotes a substrate holder. Reference numeral 112 denotes a substrate on which a thin film is formed.
[0005]
The operation of the sputtering apparatus configured as described above will be described below. First, the chamber 101 is evacuated from the vacuum exhaust port 102 to about 10 ⁻⁷ Torr with a vacuum pump. Next, the discharge gas 105 is introduced into the chamber 101 through the gas introduction pipe 103 connected to one end of the chamber 101, and the pressure in the chamber 101 is maintained at about 10 ⁻³ to 10 ⁻² Torr. 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 supply 108, the electric field generated by the power supply 108 and the magnetic field generated by the magnet 110 disposed on the back surface of the target 106. As a result, ring-shaped plasma is generated near the surface of the target 106, causing a sputtering phenomenon, and a thin film is formed on the substrate 112 placed on the substrate holder 111 by the sputtered particles emitted from the target 106.
[0006]
The magnetron sputtering method has a problem that the film thickness and film quality are not uniform due to local erosion of the target. To solve this problem, for example, as described in JP-A-7-11440 Devices have been devised that generate a uniform magnetic field orthogonal to the electric field. FIG. 19 is a cross-sectional view showing a schematic configuration of an example of a sputtering apparatus that forms a uniform magnetic field orthogonal to a conventional electric field. In FIG. 19, 101 is a chamber, 102 is a vacuum exhaust port of the chamber 101 evacuated by a vacuum pump (not shown), 103 is a gas introduction pipe to the chamber 101, and 104 is a gas flow rate attached to the gas introduction pipe 103. It is a controller. A discharge gas 105 is introduced into the chamber 101 from the gas introduction tube 103, and argon gas is usually used. 106 is a target, 107 is a sputtering electrode, 108 is a power source for discharge, 109 is a magnet holder, and 110 is a magnet and is accommodated in the magnet holder 109. Reference numeral 111 denotes a substrate holder. Reference numeral 112 denotes a substrate on which a thin film is formed.
[0007]
The operation is substantially the same as that of the magnetron sputtering apparatus, but the plasma due to the discharge is generated over the entire surface of the target.
[0008]
On the other hand, as another configuration for forming a magnetic field orthogonal to the electric field, as described in detail in “Thin Film Handbook” (Japan Society for the Promotion of Science, Thin Film 131st Committee, Ohmsha, p. 186), coaxial cylindrical magnetron sputtering. There is a device. A cylindrical target and a cylindrical substrate holder are disposed so as to surround the target, and a substrate is disposed on the inner wall of the substrate holder. The magnetic field is configured to be generated in parallel with the target surface so as to surround the target, and the electric field and the magnetic field can be substantially orthogonal to each other.
[0009]
[Problems to be solved by the invention]
However, in the conventional configuration as shown in FIG. 18, since the magnetic flux is directed in the same direction over the entire surface of the target, the 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 plane. As a result, erosion of the target in the direction of the force received by the electrons progresses rapidly, and in the reverse direction, the erosion progresses slowly, and the erosion does not progress uniformly. As a result, not only the material utilization efficiency of the target material is extremely bad, but also the problem that the film thickness uniformity of the thin film formed on the substrate surface cannot be ensured occurs.
[0010]
Further, in the conventional configuration shown in FIG. 19, charged particles (ions, electrons) in the plasma jump out of the target without being confined on the target. As a result, the plasma density is lowered and the film formation rate is slow.
[0011]
On the other hand, in the coaxial cylindrical magnetron sputtering apparatus, the charged particles (ions, electrons) in the plasma are confined in a closed path surrounding the target, with the electric field and the magnetic field orthogonal to each other over the entire surface of the cylindrical target. The problem of uneven or reduced speed can be avoided. However, since the target is a column type and the substrate holder is a cylinder type, the shape and size of the substrate are limited. In particular, when the substrate becomes large, the sputtering apparatus becomes very large with this, causing a problem that the practicality is lost.
[0012]
An object of the present invention is to solve the above-mentioned problems, and to provide a sputtering apparatus that can progress the erosion of a target substantially uniformly and increase the formation speed of a thin film.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0014]
The sputtering apparatus of the present invention is a sputtering apparatus that performs sputtering using a flat target (6), and generates a magnetic field that generates a magnetic field substantially parallel to the flat target (6) on both the front and back sides of the flat target (6). And a film is formed by sputtering on both the front and back surfaces of the flat plate target (6).
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0017]
(Embodiment 1)
FIG. 1 is a cross-sectional view showing a schematic configuration of an example of a sputtering apparatus for performing the sputtering method according to the 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 communicated with a vacuum pump (not shown), 3 is a gas introduction pipe provided in the chamber 1, 4 is a gas introduction pipe 3 It is a gas flow controller attached. Reference numeral 5 denotes a discharge gas introduced into the chamber 1 from the gas introduction tube 3, and argon gas is usually used. 6 is a rectangular target disposed in the chamber 1, 7 is a sputtering electrode for supporting the target 6 attached to the chamber 1 via insulators 80 and 81, and 8 is a negative voltage or a high-frequency voltage applied to the sputtering electrode 7. A direct current or high frequency power source for discharge, a pair of magnet holders 9 arranged in the chamber 1 and along a pair of edges along the longitudinal direction of the target 6, and 21 held in the pair of magnet holders 9 The magnetic field 51 is formed by ring-shaped magnets arranged along a pair of edges of the target 6. Reference numerals 11 a and 11 b denote substrate holders disposed at positions facing both the front and back surfaces of the target 6 in the chamber 1. Reference numerals 12a and 12b denote substrates held by the substrate holders 11a and 11b, respectively, on which thin films are formed.
[0018]
FIG. 2 is an exploded perspective view showing a schematic configuration of a portion of the sputtering electrode 7 in the sputtering apparatus shown in FIG.
[0019]
In FIG. 2, 21 is a ring-shaped magnet. Reference numeral 22 denotes one of target constituent members made of a target material, and is provided with a cooling water channel 23. A lid 24 for closing the water channel is made of the same material as the target constituent member 22 and is fastened to the target constituent member 22 via a metal seal 25. That is, the target 6 includes a target constituent member 22, a cooling water channel 23, a lid 24, and a metal seal 25. Reference numeral 26 denotes a water passage for guiding the cooling water to the target 6 and is connected to the lid 24 via an insulator 27. Reference numeral 28 denotes an earth shield. Reference numeral 29 denotes power supply wiring, one of which is connected to the target 6 and the other is connected to a sputtering power source (not shown).
[0020]
By configuring as described above, a magnetic field substantially parallel to the target surface can be generated on the target 6 on the entire surface of the target and the pair of side surfaces. Further, the electric field is similarly formed on the entire front and back surfaces of the target and the pair of side surfaces by the power applied to the target 6.
[0021]
FIG. 3 is a perspective view schematically showing the state in the vicinity of the target 6 and shows a magnetic field 51 formed on the target and a moving direction 52 of electrons in the plasma. At this time, the plasma formed on the target is formed on the entire surface of the target, and the plasma is formed so as to surround the target 6. Electrons in the plasma are confined in a closed path by the action of an electric field and a magnetic field. As a result, the target erosion progresses substantially uniformly, the plasma density is improved, and the thin film formation rate is improved.
[0022]
FIG. 4 shows the magnetic flux density on the AA ′ line in FIG. 3 as an example. FIG. 5 shows the deposition rate distribution of the thin film formed on the substrate at this time. Further, FIG. 6 schematically shows a state after erosion of the target 6 in a vertical section including the line AA ′ of FIG. 3.
[0023]
As can be seen from the above, according to the present embodiment, a high film formation rate can be realized, target erosion can be made substantially uniform, and material utilization efficiency increases.
[0024]
Further, as an effect of the present embodiment, as shown in FIG. 6, since target erosion proceeds on both the front and back surfaces of the target, a film can be simultaneously formed on two substrates with respect to one sputtering electrode. The point is mentioned.
[0025]
(Embodiment 2)
FIG. 7: is a perspective view which shows schematic structure of an example of the sputtering electrode of the sputtering device for enforcing the sputtering method concerning Embodiment 2 of this invention. The general configuration is the same as in the first embodiment, except that a pair of ring magnets 21 arranged along the edge of the target 6 is composed of a plurality of magnets, and each magnet is different. It is that it is comprised so that intensity | strength of can be changed.
[0026]
In the present embodiment, in the example of FIG. 7, the ring-shaped magnet 21 is composed of 12 magnets, and the magnets 21a, 21b, 21c, 21d, 21e, 21f, 21g, 21h, 21i, 21j, 21k, 21l The ratio of magnet strength was 2: 1.5: 1.5: 1: 2: 2: 2: 1.5: 1.5: 1: 2: 2.
[0027]
FIG. 8 shows an example of the magnetic flux density on the BB ′ line in FIG. 7, and the magnetic field strength along the direction of the outer product of the electric field generated by the sputtering power supply 8 and the magnetic field generated by the ring magnet 21. Is continuously weakening.
[0028]
With the configuration as described above, it is possible to substantially eliminate the plasma bias accompanying the movement of electrons along the BB ′ line, and to make the plasma density substantially uniform over the entire surface of the target.
[0029]
FIG. 9 shows an example of the formation rate distribution of the film formed on the substrate in this embodiment. FIG. 10 shows a state after erosion of the target 6 in a vertical section including the line BB ′ of FIG.
[0030]
In the second embodiment, the same effects as in the first embodiment can be obtained, and the film thickness uniformity and the material utilization efficiency can be further improved as shown in FIGS.
[0031]
(Embodiment 3)
FIG. 11: is sectional drawing which shows schematic structure of an example of the sputtering device for enforcing the sputtering method concerning Embodiment 3 of this invention. The general configuration is the same as in the first and second embodiments, except that a ring-shaped magnet 31 having substantially the same shape as the magnet is installed at a position between the pair of ring-shaped magnets 21, and That is, the ring-shaped magnet 21 is configured to move along a different edge from the pair of edges of the target 6 along which the ring-shaped magnet 21 is aligned.
[0032]
In FIG. 11, the ring-shaped magnet 31 is accommodated in the magnet holder 30. The magnet holder 30 is held by a shaft 32. The shaft 32 is connected to the ball screw 33, and the shaft 32 is moved in the left-right direction on the paper surface as the ball screw 33 rotates. One end of the ball screw 33 is held by a housing 34 having a bearing, and the other end is held by a housing 35 having a bearing and an oil seal. The ball screw 33 is rotationally driven by a motor 36. The two motors 36 are synchronously controlled by the control unit 37.
[0033]
FIG. 12 is a perspective view schematically showing a schematic configuration in the vicinity of the sputtering electrode of FIG. With the above configuration, the ring-shaped magnet 31 moves in the directions 61 and 62, and the distance from the pair of ring-shaped magnets 21 arranged along the pair of edges of the target 6 can be continuously changed.
[0034]
FIG. 13 shows an example of the relationship between the distance between the ring-shaped magnets 21 and 21 and the normalized formation speed of the film formed on the substrate. As shown in FIG. 13, as the distance between the magnets increases, the film formation rate decreases. That is, when the size of the substrate 12 is large and the target 6 is large, the distance between the magnets increases and the film formation rate decreases as shown in FIG.
[0035]
In this embodiment, even when a large target is used, the ring-shaped magnet 31 can be installed to prevent a decrease in the film formation rate. Further, during film formation, as shown in FIG. 14, the ring magnet 31 is moved in the order of (A) → (B) → (C) → (B) → (A) → (B) →. A substantially uniform erosion over the entire surface is obtained.
[0036]
In the third embodiment, the same effect as in the first embodiment can be obtained, and a film can be formed on a large substrate without reducing the film formation speed.
[0037]
(Embodiment 4)
FIG. 15: is sectional drawing which shows an example of schematic structure of the sputtering electrode vicinity of the sputtering device for enforcing the sputtering method concerning Embodiment 4. In FIG. The general configuration is the same as that of the first embodiment, except that the target 6 is divided into targets 6a and 6b, connected via an insulator 82, and power is supplied to the targets 6a and 6b, respectively. The power sources 8a and 8b to be supplied are connected, and the ring magnet 31 having substantially the same shape as the ring magnet 21 is along the edges of the targets 6a and 6b and faces the pair of ring magnets 21. The magnet holder 30 that is disposed and accommodates the ring-shaped magnet 31 is fixed to the chamber 1 (not shown) via the shaft 38.
[0038]
FIG. 16 is a perspective view showing a schematic configuration in the vicinity of the sputtering electrode of FIG. With the above configuration, sputtering can be performed without weakening the magnetic field on the target even when the target is enlarged, and a reduction in the formation rate can be prevented.
[0039]
In the fourth embodiment, the same effect as in the first embodiment can be obtained, and a thin film can be formed on a large substrate without reducing the formation speed.
[0040]
In the present embodiment, the number of target divisions is two, but there is no problem even if the number of target divisions is three or more. However, since the increase in the number of target divisions reduces the surface area of the target surface facing the substrate, it depends on the substrate size, but is preferably within about 5.
[0041]
(Embodiment 5)
FIG. 17: is sectional drawing which shows schematic structure of the sputtering device for enforcing the sputtering method concerning Embodiment 5 of this invention. Although the general configuration is the same as that of the first embodiment, the difference is that the substrate holders 91a and 91b holding the substrates 12a and 12b can be moved in front of the target, and the position adjacent to the chamber 1 Are provided with chambers 95 and 96 through gate valves 94a and 94b.
[0042]
After film formation on the substrates 12a and 12b in the chamber 95, the gate valve 94a is opened, the substrate holders 91a and 91b are transferred into the chamber 1 by the moving means 92 of the substrate holder, and the gate valve 94a is closed. Thereafter, a film is formed while continuing to move the substrate holders 91a and 91b. Thereafter, the gate valve 94 b is opened, the substrate holders 91 a and 91 b are transferred into the chamber 96, and another type of film is formed in the chamber 96. The moving means 92 may be a well-known device, and for example, a mechanism that rotates a rail and a gear installed thereon by a motor can be used.
[0043]
With the above configuration, the thickness of the film formed on the substrate can be made substantially uniform. In addition, a multilayer film can be formed on the substrate.
[0044]
In the fifth embodiment, the same effects as in the first embodiment can be obtained, and the film thickness of the film formed on the substrate can be made more uniform. In addition, many kinds of multilayer films can be formed on the substrate.
[0045]
In the present embodiment, an example in which a film is formed in the chambers 95 and 96 adjacent to the chamber 1 has been described, but there is no problem even if other vacuum processing functions such as preliminary exhaust and heating are performed.
[0046]
【The invention's effect】
As described above, according to the present invention, the plasma density on the target surface is substantially uniform, the target erosion is substantially uniform, the utilization efficiency of the target material is improved, and the generation of a thin film formed on the substrate is generated. The advantageous effect that the speed is improved and the uniformity of the film thickness can be secured is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of an example of a sputtering apparatus for performing a sputtering method according to Embodiment 1 of the present invention.
FIG. 2 is an exploded perspective view showing a schematic configuration in the vicinity of a sputtering electrode of the sputtering apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a diagram schematically showing a magnetic field near a target 6 and a moving direction of electrons in plasma in the first embodiment of the present invention.
4 is a diagram showing an example of a magnetic flux density on a target surface on the AA ′ line in FIG. 3; FIG.
5 is a diagram showing an example of a formation rate distribution of a thin film formed on a substrate in Embodiment 1. FIG.
6 is a cross-sectional view schematically showing an erosion state of a target of the sputtering apparatus in the first embodiment. FIG.
FIG. 7 is a schematic perspective view showing an example of a structure in the vicinity of a sputtering electrode of a sputtering apparatus for performing a sputtering method according to a second embodiment of the present invention.
8 is a diagram showing an example of the magnetic flux density on the target surface on the BB ′ line in FIG. 7; FIG.
FIG. 9 is a diagram showing an example of a formation rate distribution of a film formed on a substrate in the second embodiment.
FIG. 10 is a cross-sectional view schematically showing an erosion state of a target of a sputtering apparatus in a second embodiment.
FIG. 11 is a cross-sectional view showing a schematic configuration of an example of a sputtering apparatus for performing a sputtering method according to Embodiment 3 of the present invention.
FIG. 12 is a schematic perspective view showing an example of a structure in the vicinity of a sputtering electrode of a sputtering apparatus for performing a sputtering method according to a third embodiment of the present invention.
FIG. 13 is a diagram showing an example of the relationship between the distance between magnets and the film formation speed.
14A to 14C are diagrams each showing an example of a state of movement of a ring-shaped magnet of a sputtering apparatus in Embodiment 3. FIG.
FIG. 15 is a cross-sectional view showing an example of a schematic configuration in the vicinity of a sputtering electrode of a sputtering apparatus for performing a sputtering method according to a fourth embodiment of the present invention.
FIG. 16 is a schematic perspective view showing an example of a structure in the vicinity of a sputtering electrode of a sputtering apparatus for performing a sputtering method according to a fourth embodiment of the present invention.
FIG. 17 is a cross-sectional view showing a schematic configuration of an example of a sputtering apparatus for performing a sputtering method according to a fifth embodiment of the present invention.
FIG. 18 is a cross-sectional view showing a schematic configuration of an example of a conventional magnetron sputtering apparatus.
FIG. 19 is a cross-sectional view showing a schematic configuration of an example of a sputtering apparatus having a magnet on the surface of a conventional target.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Vacuum exhaust port 3 Gas introduction pipe 4 Gas flow rate controller 5 Discharge gas 6, 6a, 6b Target 7 Sputtering electrodes 8, 8a, 8b Discharge power supply 9 Magnet holder 11a, 11b Substrate holder 12a, 12b Substrate 21 Ring -Shaped magnet 22 Target component member 23 Cooling water channel 24 Lid 25 Metal seal 26 Water channel 27 Insulator 28 Earth shield 29 Power supply wiring 30 Magnet holder 31 Ring-shaped magnet 32 Shaft 33 Ball screw 34 Housing 35 Housing 36 Motor 37 Control unit 38 Shaft 51 Magnetic field 52 Electron moving direction in plasma 80, 81, 82 Insulator 91 a, 91 b Substrate holder 92 Moving means 94 a, 94 b Gate valve 95, 96 Chamber 101 Chamber 102 Vacuum exhaust port 103 Gas introduction pipe 1 4 gas flow controller 105 a discharge gas 106 Target 107 sputtering electrode 108 discharge power supply 109 magnet holder 110 magnets 111 a substrate holder 112 substrate

Claims (7)

A sputtering apparatus for performing sputtering using a flat target, have a magnetic field generating means for generating the flat target and substantially parallel magnetic field on both sides of the planar target, film formation by sputtering on the front and back surfaces of the flat plate target Sputtering apparatus characterized by performing . 2. The sputtering apparatus according to claim 1 , wherein a pair of ring-shaped magnets are respectively arranged along a pair of edges of the flat plate target. The sputtering apparatus according to claim 2 , wherein the ring-shaped magnet is composed of a divided permanent magnet or an electromagnet. The sputtering apparatus according to claim 3 , wherein the individual permanent magnets or electromagnets constituting the ring-shaped magnet have different intensities. The sputtering apparatus according to any one of claims 2 to 4 , wherein a ring-shaped magnet having substantially the same shape as the ring-shaped magnet is installed at a position sandwiched between the pair of ring-shaped magnets. The sputtering apparatus according to claim 5 , wherein the ring-shaped magnet is installed so as to be movable between a pair of ring-shaped magnets sandwiching the magnet. The sputtering apparatus according to any one of claims 1 to 6 , wherein the flat plate target is configured by bonding a plurality of targets, and a ring-shaped magnet is disposed along the bonding surface. apparatus.

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