JP3126405B2 - Sputter deposition equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputter deposition apparatus, and more particularly to a sputter deposition apparatus suitable for forming a uniform and high-density plasma over a large area.

[0002]

2. Description of the Related Art Sputter deposition technology has been widely used in almost all fields, including the semiconductor industry, as one of means for forming thin films of various materials.
However, there are many problems such as substrate impact due to negative ions and δ electrons emitted from the target. Generally, a well-known magnetron sputtering method, a facing sputtering method, and the like are often used.

However, in these methods, in order to trap δ electrons, it is necessary to form a magnetic field of one hundred to several hundred gauss by a magnetic field generating means provided on the back surface of the electrode. These magnetic fields affect not only the vicinity of the target but also the surface of the film-forming substrate. In particular, when a magnetic film is formed, it greatly affects the direction in which magnetic domains are formed in the magnetic film. Furthermore, if the electrodes are enlarged or the distance between the electrodes is increased in order to increase the throughput, a larger magnetic field generator is required, and as a result, the magnetic field greatly affects the surroundings. On the other hand, reducing the internal stress of the film formed on the substrate is also an important issue.

As a method corresponding thereto, a well-known conventional sputtering method using a bipolar electrode is used, for example, for forming a magnetic film and a protective film for the magnetic film.

However, when the conventional sputter deposition apparatus is used, the film forming speed is not sufficient as compared with other methods. This is because it is difficult to limit the diffusion of the discharge plasma formed between the two electrodes, and the density of the plasma is reduced. As a result, compared to the magnetron method or the like, there is a problem that a sputtering rate of only a fraction is obtained and the throughput is low.

Therefore, it has been considered that the processing capacity is improved by enlarging the electrodes. However, with the enlargement of the electrodes, the diffusion of plasma from the region formed between the two electrodes to the outside becomes remarkable, and Since the confinement efficiency is reduced, the film formation rate is reduced, and the difference in the film thickness distribution between the central part and the peripheral part of the electrode is increased.

Techniques for solving the above problems include:
There is a technique described in the specification of Japanese Patent Application No. 62-196369 . This technique is a facing target sputtering method in which a magnet is arranged behind an electrode to prevent plasma diffusion.
However, in this method, a magnetic flux is formed in a direction perpendicular to the two electrodes, and the film is formed on the substrate surface while a magnetic field in the vertical direction is applied.

Further, US Pat. Pat. 3,669,86
The techniques disclosed in Patent Documents 0 and 4,673,482 attempt to form a film while arranging a yoke around a substrate in a vacuum vessel and applying a magnetic field parallel to the substrate surface to the substrate surface. It is.

There is also a technique described in Japanese Patent Application Laid-Open No. Hei 2-163373. This technique is a technique in which a plurality of magnetic devices having different magnetic properties are alternately provided in the circumferential direction near an outer peripheral surface of a space formed between a target electrode and a substrate electrode.

[0010]

SUMMARY OF THE INVENTION The above-mentioned JP-A-2-163 is disclosed.
According to the technique described in Japanese Patent No. 373, a cusp is formed by a magnetic device disposed near an outer peripheral surface of a space formed between a target electrode and a substrate electrode, and plasma is generated near the center of the outer peripheral surface of this space. Diffusion can be prevented. However, since no cusps are formed between the magnetic device and the target electrode and between the magnetic device and the substrate electrode, the diffusion of plasma cannot be prevented.

An object of the present invention is to provide a sputter deposition apparatus which improves plasma confinement efficiency without affecting a substrate by a magnetic field and makes the plasma density in a discharge space between two electrodes uniform. is there.

[0012]

An object of the present invention is to provide a sputter deposition apparatus having a target electrode and a substrate electrode opposed to the target electrode. Magnetic field generating means, second magnetic field generating means disposed near the outer periphery of the substrate electrode, and the two electrodes near the outer peripheral surface of a space formed between the target electrode and the substrate electrode And a third magnetic field generating means arranged along the outer peripheral surface at an intermediate position between the magnetic field generating means and the magnetic pole of the third magnetic field generating means. The polarities of the magnetic poles of the first and second magnetic field generating means facing each other can be achieved by different sputter deposition apparatuses.

All of the first, second and third magnetic field generating means may be permanent magnets, or at least one of them may be a permanent magnet.

[0014]

The lines of magnetic force concentrate between the magnetic pole of the first magnetic field generating means and the magnetic pole of the third magnetic field generating means. Similarly, the second
Lines of magnetic force concentrate between the magnetic pole of the third magnetic field generating means and the magnetic pole of the third magnetic field generating means. As a result, a cusp-shaped magnetic field is formed in the vicinity of the outer peripheral surface of the space formed between the target electrode and the substrate electrode. Therefore, when electrons and ions in the plasma generated in the discharge space attempt to diffuse outward, the electrons and ions move perpendicular to both the direction of movement of the electrons and ions and the direction of the cusp magnetic field component perpendicular to the direction of movement. In the direction, the above electrons and ions receive the force from the magnetic field and bend in the direction of movement, making it difficult to diffuse, promote re-ionization of plasma, and prevent a sharp decrease in plasma density near the electrode outer periphery. In addition, the plasma density in the film formation space can be improved. As a result, the film forming speed is improved, and the throughput is improved.

[0015]

Next, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view of a sputter deposition apparatus 100 according to the first embodiment. As shown in FIG. 1, a target 2 is mainly held in a vacuum vessel 1, and a target electrode 3 serving as a cathode and a substrate 4 on which a film is formed are held when sputtering discharge is performed. And a substrate electrode 5 serving as an anode when performing the above.

The target electrode 3 and the substrate electrode 5 are insulated from the vacuum vessel 1 by insulators 11 and 12, respectively. Sputtering power is supplied from the high frequency power supplies 22 and 24 via the matching boxes 21 and 23. The electrode for sputtering may be a DC power supply instead of a high-frequency power supply depending on a film forming material. Further, the substrate electrode may be directly grounded.

The sputtering gas is introduced into the vacuum chamber through the gas inlet 6. The gas in the vacuum vessel is exhausted by a cryopump 9 attached via a gate valve 8 attached to an exhaust section of the vacuum vessel.

As shown in FIG. 1, this embodiment is characterized in that a magnetic field generating means 30 is arranged near the outer periphery of the target electrode 3 and a magnetic field generating means 31 is arranged near the outer periphery of the substrate electrode 5. The magnetic field generating means 32 is disposed along the outer peripheral surface at a position between the two electrodes near the outer peripheral surface of the space formed between the target electrode 3 and the substrate electrode 5. As the magnetic field generating means, a permanent magnet may be used. Also, the magnetic field generating means 30, 31
May be either inside or outside the electrode near the outer periphery of the electrodes 3 and 5, respectively. From the viewpoint of efficiency, the inside is preferable.

The magnetic field generating means 30, 31, 32
The polarities of the magnetic poles are different for the opposite magnetic poles. For example, as shown in FIG.
If the inner magnetic pole is an N pole, the outer magnetic pole is an S pole. The magnetic field generating means 32 needs to have the same magnetic pole in the circumferential direction. This is because the magnetic field generating means 3
This is because the magnetic path 33 (indicated by a broken line in FIG. 1) of the magnetic force lines from 0 and 31 is collected at the magnetic pole of the magnetic field generating means 32.

Next, the shape of the magnetic field generating means 32 will be described with reference to FIG. FIG. 2 is a perspective view of the magnetic field generating means 32. The shapes of the magnetic field generating means 32 are shown in FIGS.
As shown in FIG.
As shown in (e), it may be annular, and as shown in (c) of the figure, it is an aggregate in which a plurality of magnets are combined and has a shape as shown in (a) or (b). It may be what is.

Next, the operation of forming a film using the sputter deposition apparatus 100 according to the present embodiment will be described with reference to FIG. FIG. 8 shows the magnetic field generating means 3
FIG. 2 is an explanatory diagram showing the operation of 0, 31, and 32, and is an example of a magnetic field distribution in the right half of the sputter deposition apparatus 100 shown in FIG. Dashed lines 33 are equipotential lines, and are indicated by indicating the directions of magnetic force lines.

In order to form plasma, first, a discharge gas is supplied from a gas inlet 6 into a space (discharge space 10) formed between the target electrode 3 and the substrate electrode 5. Then, the high frequency power supplies for sputtering 22 and 24
By applying a voltage to the two electrodes 3 and 5, a discharge plasma is induced in the discharge space 10.

At this time, in the conventional conventional inter-electrode discharge, the discharge plasma density decreases rapidly as it goes radially outward from the center. Therefore, the film formed for this purpose is thicker at the center and thinner at the outer side, and this tendency tends to become more remarkable as the input power density increases.

However, in the sputter deposition apparatus 100 according to the present embodiment, as shown in FIG. Plasma discharge space 1
Diffusion outside 0 can be prevented. As a result, the plasma density distribution in the discharge space 10 can be made uniform, and the uniformity of the formed film is also improved.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 3 is a sectional view of a sputter deposition apparatus 200 according to the second embodiment. The basic configuration of the sputter deposition apparatus 200 according to the present embodiment is shown in FIG.
Sputter deposition apparatus 10 according to the first embodiment shown in FIG.
Since the basic configuration is the same as the basic configuration of 0, the description is omitted.
The features of the sputter deposition apparatus 200 according to the present embodiment reside in the position where the magnetic field generating means is disposed and the provision of the magnetic path material.

As shown in FIG. 3, the magnetic field generating means 35 such as a magnet is arranged along the outer wall surface at a position near the outer wall surface of the vacuum vessel 1 and between the two electrodes 3 and 5. As shown in FIG. 3, the magnetic path members 39, 40, 41, 42, and 50 are used as yokes so that the magnetic field lines shown in FIG. 8 are formed near the outer peripheral portion of the discharge space 10. Used. The magnetic path member 39 is provided along the outer wall of the vacuum vessel 1. The magnetic path member 40 is disposed at a position where the magnetic path member 39 is magnetically connected to the magnetic path member 50 disposed near the outer peripheral portion of the substrate electrode 5. Further, the magnetic path member 41 is arranged at a position where the magnetic path member 39 and the magnetic path member 50 arranged near the outer peripheral portion of the target electrode 3 are magnetically connected. Further, the magnetic path member 40 is disposed at a position where the magnetic field generating means 35 disposed outside the vacuum chamber and the magnetic path member 50 are magnetically connected.

The operation of the magnetic field lines 51 from the magnetic field generating means 35 in the sputter deposition apparatus 200 according to the present embodiment is different from the sputter deposition apparatus according to the first embodiment in that plasma generated in the discharge space 10 is confined. 1
Since it is the same as the case of 00, its description is omitted.

A special effect of the sputter deposition apparatus 200 according to the present embodiment is that the magnetic field generating means 35 is disposed outside the vacuum chamber 1 and the magnetic path material 39 is used in the vacuum chamber 1 so that the magnetic field generating means 35 is used. The means 35 is not affected by the plasma, and can prevent the magnetic field generating means 35 from deteriorating due to heat.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 4 is a sectional view of a sputter deposition apparatus 300 according to the third embodiment. The basic configuration of the sputter deposition apparatus 300 according to this embodiment is shown in FIG.
Sputter deposition apparatus 20 according to the second embodiment shown in FIG.
Since the basic configuration is the same as the basic configuration of 0, the description is omitted.
The feature of the sputter deposition apparatus 300 according to the present embodiment resides in that the coil 36 is used as the magnetic field generating means.
The coil 36 is arranged along the outer wall of the vacuum vessel 1 as shown in FIG.

As a result of using the coil 36 as the magnetic field generating means, the magnetomotive force can be easily changed only by changing the current value of the coil power supply 42.
It can be easily changed according to the discharge conditions.

An experimental example using the sputter deposition apparatus 300 according to the fourth embodiment will be described below. As shown in FIG. 4, by providing a cusp magnetic field near the outer peripheral portion of the discharge space 10, the film forming rate is increased from 300 ° / min to 520 °.
/ Min, it is possible to increase the speed by about 70%. Also,
With an 8-inch target diameter, the film formation distribution was ± 19% to ± 3% in the range of φ160, and the uniform distribution area within 3% was increased by 2.5 times or more.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 5 is a sectional view of a sputter deposition apparatus 400 according to the fourth embodiment. The basic configuration of the sputter deposition apparatus 400 according to this embodiment is shown in FIG.
Sputter deposition apparatus 30 according to the third embodiment shown in FIG.
Since the basic configuration is the same as the basic configuration of 0, the description is omitted.
The feature of the sputter deposition apparatus 400 according to the present embodiment is that, as shown in FIG. 5, the coils 37 and 38 used as the magnetic field generating means include the target electrode side magnetic path coil 37 and the substrate electrode side magnetic path coil 38. In that they can be independently adjusted by the coil power supplies 44 and 45, respectively.

The lines of magnetic force when the coils used as the magnetic field generating means are divided into two upper and lower systems will be described. A dashed line 55 indicates magnetic lines of magnetic flux excited in the magnetic path material 56 by the coil power supply 44 and the target electrode side magnetic path coil 37. Similarly, the magnetic flux is also excited by the coil power supply 45 and the substrate-electrode-side magnetic path coil 38. That is, the strengths of the upper and lower coils 37 and 38 are adjusted by the power sources 44 and 45.
Thus, the magnetic field shape and the magnetic flux density according to various process modes can be obtained since the adjustment can be made independently.
Further, the discharge state can be monitored and adjusted according to the process conditions.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 6 is a sectional view of a sputter deposition apparatus 500 according to the fifth embodiment. The basic configuration of a sputter deposition apparatus 500 according to this embodiment is shown in FIG.
Sputter deposition apparatus 10 according to the first embodiment shown in FIG.
Since the basic configuration is the same as the basic configuration of 0, the description is omitted.
The feature of the sputter deposition apparatus 500 according to the present embodiment lies in that the cathode-side magnetic field generating means is also used as a sputtering magnet. As shown in FIG. 6, two cathode-side magnetic field generating means are provided near the outer peripheral portion of the target electrode 3 (in FIG. 6, the magnetic field generating means is not shown near the outer peripheral portion because the magnetic field generating means is emphasized and shown). Permanent magnet 6
Magnetic field generating means such as 1 and 62 are arranged.

The operation of the two permanent magnets 61 and 62 will be described. From the S pole of the permanent magnet 61, the magnetic flux is directed to the N pole of the permanent magnet 62, and
The magnetic flux 64 is also directed to the pole. From the S pole of this permanent magnet 61 to N
The magnetic flux 64 directed to the pole is called leakage magnetic flux and does not contribute to the magnetron magnetic field. However, by arranging the permanent magnet 63 at the position shown in FIG. 6, a part of the leakage magnetic flux 64 can be collected, so that a magnetic wall can be formed near the outer peripheral portion of the discharge space 10. As a result, it is possible to prevent the plasma formed in the discharge space 10 from diffusing to the outside of the discharge space 10.

Further, in order to increase the above effect, it is necessary to make the generated magnetic flux of the permanent magnet 61 larger than that of the permanent magnet 62.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 7 is a sectional view of a sputter deposition apparatus 600 according to the sixth embodiment. The basic configuration of the sputter deposition apparatus 600 according to the present embodiment is shown in FIG.
Sputter deposition apparatus 50 according to the fifth embodiment shown in FIG.
Since the basic configuration is the same as the basic configuration of 0, the description is omitted.
The feature of the sputter deposition apparatus 600 according to the present embodiment is that no magnetic field generating means is arranged near the outer peripheral portion of the substrate electrode 5. As shown in the figure, even without disposing the magnetic field generating means near the outer peripheral portion of the substrate electrode 5, an effect similar to that of the sputter deposition apparatus 500 shown in FIG. 6 can be obtained. Therefore, there is an effect that the structure of the substrate electrode 5 can be simplified.

[0038]

According to the present invention, since a magnetic wall can be formed near the outer peripheral portion of the discharge space, the discharge plasma density in the electrode can be increased and maintained uniformly. As a result, the film forming rate can be improved, that is, the throughput can be improved. Also, a large area discharge electrode can be formed with an extremely good distribution.

[Brief description of the drawings]

FIG. 1 shows a sputter deposition apparatus 1 according to a first embodiment.
Cross section of 00

FIG. 2 is a perspective view of a magnetic field generating means.

FIG. 3 shows a sputter deposition apparatus 2 according to a second embodiment.
Cross section of 00

FIG. 4 shows a sputter deposition apparatus 3 according to a third embodiment.
Cross section of 00

FIG. 5 shows a sputter deposition apparatus 4 according to a fourth embodiment.
Cross section of 00

FIG. 6 shows a sputter deposition apparatus 5 according to a fifth embodiment.
Cross section of 00

FIG. 7 shows a sputter deposition apparatus 6 according to a sixth embodiment.
Cross section of 00

FIG. 8 is an explanatory diagram showing the operation of the magnetic field generating means.

[Explanation of symbols]

1 vacuum chamber, 2 target, 3 target electrode, 4
... substrate, 5 ... substrate electrode, 6 ... gas inlet, 10 ... discharge space, 30, 31, 32, 61, 62, 63 ... permanent magnet,
33, 64: magnetic field lines, 36: coil, 37: target electrode side magnetic path coil, 38: substrate electrode side magnetic path coil,
44, 45: coil power supply, 39, 40, 56: magnetic path material.

Continuation of front page (56) References JP-A-55-91975 (JP, A) JP-A-61-60881 (JP, A) JP-A-63-65072 (JP, A) JP-A-64-55815 (JP) , A) JP-B 60-12426 (JP, B2) JP-B 63-43466 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58

Claims (4)

(57) [Claims] 1. A sputter deposition apparatus comprising: a target electrode; and a substrate electrode disposed opposite to the target electrode. A first magnetic field generating means disposed near an outer periphery of the target electrode; A second magnetic field generating means disposed in the vicinity of the outer periphery of the electrode; and a second magnetic field generating means disposed between the two electrodes in the vicinity of the outer periphery of the space formed between the target electrode and the substrate electrode. And a third magnetic field generating means disposed along the sputter deposition apparatus. 2. The polarity of a magnetic pole of said third magnetic field generating means,
2. The sputter deposition apparatus according to claim 1, wherein the polarities of the magnetic poles of the first and second magnetic field generating means opposite to the magnetic poles of the third magnetic field generating means are different from each other. 3. A sputter deposition apparatus provided with a target electrode and a substrate electrode arranged opposite to the target electrode in a vacuum vessel capable of evacuating, wherein the two electrodes are provided near an outer wall surface of the vacuum vessel. A magnetic field generating means disposed along the outer wall surface at an intermediate position between the electrodes, and formed near the outer peripheral portion of the target electrode and the outer peripheral portion of the substrate electrode, and sandwiched between the target electrode and the substrate electrode. A magnetic path for magnetically connecting a location near the outer peripheral surface of the space to be formed and along the outer peripheral surface between the two electrodes with a magnetic field generated by the magnetic field generating means.
Sputtering deposition apparatus characterized by being configured to include a timber, the. 4. The magnetic field generating means comprises two magnetic field generating means, and one magnetic field generating means generates the vicinity of the outer peripheral portion of the target electrode and the location along the outer peripheral surface from the magnetic field generating means. The other magnetic field generating means magnetically connects the vicinity of the outer peripheral portion of the substrate electrode and a location along the outer peripheral surface with a magnetic field generated from the magnetic field generating means. The sputter deposition apparatus according to claim 3, wherein: