JPH04371577A - Magnetron type sputtering device - Google Patents

Abstract

PURPOSE:To make a target small-sized and to reduce the consumption of power and cooling water by rotating the target. CONSTITUTION:The magnetron sputtering device 1 is provided with a cathode 12 contg. a magnetic field generator 14 and with a target 13 set on its upper surface and a wafer holder 15 arranged above the target 13. A driving part 16 is connected to the edge of the cathode 12 through a driving shaft 17, and the axial center of the shaft 17 is almost aligned with the perpendicular PL passing the center of a wafer 71 held by the holder 15.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron type sputtering apparatus.

0002

2. Description of the Related Art Metal films for semiconductor devices are mainly formed by sputtering. The thickness of the formed metal film is required to have a minimum value and a maximum value within ±5% of the set thickness. However, as wafers become larger in diameter, it becomes more difficult to satisfy this requirement. Therefore, film formation is performed using a magnetron sputtering device. In order to obtain a highly uniform film thickness distribution, the magnetron type sputtering apparatus 51 shown in FIG. 5 includes a rotating magnetic field generator (usually a permanent magnet) 53 inside the cathode 52. This magnetic field generator 53 is driven by a drive unit 55 via a rotation shaft 54.
For example, it is rotated in the direction of arrow C. The axis of the drive shaft 54 is aligned with a perpendicular line PL passing through the center of the wafer 71 held by the wafer holder 56. Further, the target 57 is formed to be slightly larger than the rotating diameter of the rotating magnetic field generator 53, and is installed on the upper surface of the cathode 52. Alternatively, the magnetic field generator 53 may be formed of a plurality of electromagnets instead of a permanent magnet. That is, a plurality of electromagnets each having an S pole and an N pole are arranged at a predetermined distance in the radial direction of the cathode around the perpendicular line PL. Electromagnets each having a south pole and a north pole are sequentially operated around the circumferential direction of the cathode to generate a magnetic field. Alternatively, as shown in FIG. 6, with the wafer holding surface 62a of the wafer holder 62 tilted with respect to the target surface 63a of the target 63, the wafer holder 62 is rotated, for example, in the direction of arrow A by the rotation driving section 64.

0003

[Problems to be Solved by the Invention] However, in the device for rotating the magnetic field generator and the device in which the magnetic field generator is formed by an electromagnet, as explained in the above-mentioned conventional technology, it is difficult to set the target to a diameter approximately twice the diameter of the wafer. must be formed. Therefore, the amount of power consumed during sputtering becomes extremely large, and the energy utilization efficiency per wafer becomes low. Also, a large amount of cooling water is required to cool the target. As a result, energy and water conservation cannot be achieved. Further, in a device that tilts and rotates a wafer holder with respect to a target, it is difficult to mount a wafer on the tilted wafer holder using a normal wafer transfer device. Therefore, a special wafer transfer device is required to automatically attach the wafer to the wafer holder, which increases the cost of the device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetron type sputtering apparatus that is energy-saving and water-saving, and is capable of automatically attaching and detaching wafers.

[0005]

SUMMARY OF THE INVENTION The present invention is a magnetron type sputtering apparatus that has been made to achieve the above object. In other words, it is a magnetron type sputtering apparatus that is equipped with a cathode that is equipped with a magnetic field generator and a target on the top surface, and a wafer holder that is placed above the target. A drive unit is provided to rotate the wafer, and the axis of the drive shaft is substantially aligned with a perpendicular line passing through the center of the wafer held in the wafer holder.

[0006]

[Operation] In the magnetron type sputtering apparatus having the above configuration, the cathode rotates about a perpendicular line passing through the center of the wafer, and a sputtered film is formed on the entire surface of the wafer using a target having a diameter approximately 1/2 of the wafer diameter. be done. Also, similar to the conventional device in which the magnetic field generator rotates, the magnetic field is applied almost uniformly to the wafer surface.

[0007]

Embodiment An embodiment of the present invention will be explained with reference to the schematic sectional view shown in FIG. As shown in the figure, a cathode 12 is provided inside a sputtering chamber 11 having a gas intake pipe 21 and an exhaust pipe 22. A target 13 is provided on the upper surface of the cathode 12. This target 13 is
It is formed into a disk shape with a diameter slightly smaller than the diameter of the cathode 12 and approximately 1/2 the diameter of the wafer 71 . A magnetic field generator 14 is provided inside the cathode 12 . This magnetic field generator 14 has, for example, N (S
) pole permanent magnet is arranged, and S is placed concentrically on the outside.
It is formed by arranging (N) pole permanent magnets. Furthermore, when the diameter of the target 13 is large, the magnetic field generator 14
In this case, a plurality of permanent magnets are arranged concentrically with a permanent magnet arranged in the center with alternating polarities. Further, inside the sputtering chamber 11, the target surface 13a and the wafer holding surface 15a are made almost parallel, and the target
A wafer holder 15 is installed above 3.

A driving section 16 for rotating the cathode 12 is provided outside the sputtering chamber 11. A drive shaft 17 provided in this drive section 16 is rotatably fitted into the sputtering chamber 11 . At this time, the axis of the drive shaft 17 is made to coincide with the perpendicular line PL passing through the center of the wafer 71 held by the wafer holder 15. Further, the edge side of the cathode 12 is attached to the tip of the drive shaft 17. Furthermore, cathode 1
A target 13 is installed on the upper surface of 2 so as not to intersect with the perpendicular line PL. Therefore, the cathode 12 is rotated by the drive unit 16 around the perpendicular line PL. As the cathode 12 rotates in this manner, in order to form a sputtered film on the entire surface of the wafer 71, the target 13 must be formed to have a diameter approximately half that of the target of the conventional magnetron type sputtering device (51). Bye. Further, the driving section 16 can also be provided inside the sputtering chamber 11.

Next, a case will be described in which, for example, an aluminum film is formed as a metal film on the wafer 71 using the magnetron type sputtering apparatus 1 having the above configuration. First, the wafer 71 is held in the wafer holder 15 by a normal method. Thereafter, while a reactive gas (for example, Ar) is supplied into the sputtering chamber 11 through the gas intake pipe 21, a portion of the supplied reactive gas is exhausted through the exhaust pipe 22 to maintain the interior of the sputtering chamber 11 at a predetermined pressure. Next, the drive unit 16 is driven to rotate the cathode 12, for example, in the direction of arrow A. Subsequently, DC power is applied to the cathode 12 from a power supply (not shown) to generate plasma from the reactive gas on the target 13. At this time, a magnetic field is generated on the target 13 by a magnetic field generator 14 provided inside the cathode 12. The reactant gas turned into plasma hits the aluminum target 13 while moving in a spiral motion due to the generated magnetic field, and repels the aluminum particles forming the target 13. The repelled aluminum particles adhere to the surface 71a of the wafer 71. In this way, an aluminum film is formed on the wafer 71. The film forming conditions at this time include, for example, argon (A
r), the flow rate was 40 sccm, the pressure in the sputtering chamber was 0.4 Pa, the strength of the magnetic field was 100 G, the rotation speed of the cathode was 30 rpm, and the injection D into the target 13.
Set C power to 6kW.

By rotating the magnetic field generator 14 together with the cathode 12 during sputtering,
Similar to the magnetron sputtering device (51) in which a magnetic field generator is rotated inside the cathode described in the conventional technology, the film thickness distribution of the film formed on the wafer 71 is similar to that in the vicinity of the center of the wafer 71. Although it is formed slightly thicker than the area near the area, it is within ±5% of the standard. Also, compared to the conventional magnetron type sputtering device (51), the diameter of the target 13 is approximately 1/2, so the amount of electric power applied to the cathode 12 is approximately 1/4, and the target 14 is cooled. The amount of cooling water will also be reduced to about 1/4. Furthermore, in the magnetron type sputtering apparatus 1,
Since the wafer holding surface 15a of the wafer holder 15 is not inclined, the wafer 71 can be attached to and removed from the wafer holder 15 using a normal automatic wafer transfer device (not shown).

Although the film thickness distribution of the film formed on the wafer 71 by the magnetron type sputtering apparatus 1 described in the above embodiment is within the standard, the film is formed slightly thinner at the edge of the wafer 71 than near the center. Therefore, in order to further improve the uniformity of the film thickness distribution, a magnetron type sputtering apparatus is installed in which the target surface 13a is inclined with respect to the wafer holding surface 15a of the wafer holder 15. - Explanation will be made using an enlarged cross-sectional view of section A.

As shown in the figure, the magnetron type sputtering apparatus 2 is similar to the embodiment described above except for the attachment of the cathode 12 to the drive shaft 17. Therefore, the sputtering chamber 11, cathode 12, target 13, magnetic field generator 14, wafer holder 15, drive unit 16
A detailed explanation of the drive shaft 17 and the drive shaft 17 will be omitted.

[0013] This magnetron type sputtering device 2
Now, the cathode 12 is attached to the drive shaft 17 so that it can rotate freely in the direction of arrow A and can be fixed at any position. As an example, shaft supports 23a and 23b for sandwiching the drive shaft 17 are provided on the lower surface of the edge side of the cathode 12.
will be established. Bearing holes 24a and 24b are formed in each of the shaft support parts 23a and 23b. Further, on both sides of the tip side of the drive shaft 17, there are shafts 25a orthogonal to the drive shaft 17.
, 25b. These shafts 25a and 25b have screws 2
6a and 26b are formed. Then, the shafts 25a, 25b are inserted into the holes 24a, 24b. By engaging the nuts 27a, 27b with the screws 26a, 26b, the shaft support part 23a,
23b to fix the cathode 12 to the drive shaft 17.

The cathode 12 is tilted and attached to the drive shaft 17 so that the target surface 13a of the target 14 is tilted toward the drive shaft 17 with respect to the wafer holding surface 15a of the wafer holder 15. At this time, wafer holder 1
The inclination angle θ of the target surface 13a with respect to the plane parallel to the wafer holding surface 15a of No. 5 is appropriately set at an angle of 45° or less depending on the strength of the magnetic field generated by the magnetic field generator 14, the rotation speed of the cathode 12, etc. . If the cathode 12 is attached to the drive shaft 17 with the inclination angle θ exceeding 45°, the thickness of the film formed at the center of the wafer will be too thin, and the sputtering efficiency will be greatly reduced. therefore,
The inclination angle θ of the target surface 13a with respect to a plane parallel to the wafer holding surface 15a of the wafer holder 15 is determined by the magnetic field generator 14.
The angle is appropriately set to 45° or less depending on the strength of the magnetic field generated by the magnetic field, the rotating speed of the cathode, etc. An example of the conditions for forming an aluminum film on the wafer 71 is to use argon (Ar) as a reaction gas and set the flow rate to 40 sc.
cm, the pressure in the sputtering chamber is set to 0.4 Pa, the strength of the magnetic field is set to 100 G, the rotation speed of the cathode is set to 30 rpm, the DC power input to the target 14 is set to 6 kW, and the tilt angle θ of the cathode 12 is set to 10°. .

[0015] The magnetron type sputtering device 2
In this case, since the wafer holding surface 15a of the wafer holder 15 is not tilted, the wafer 71 can be attached to and removed from the wafer holder 15 using a normal automatic wafer transfer device. In addition, by tilting the target surface 13a and rotating the target 13, the central part side of the wafer 71 and the target 1
3 is further away than the distance between the edge side of the wafer 71 and the target 13. For this reason, the wafer 71
The amount of film formed on the center side of the area decreases. As a result, wafer 7
The film on the center side of the sputtering device 1 is no longer formed thickly, resulting in a film with even better film thickness uniformity than the film formed by the magnetron type sputtering apparatus 1 described above.

The magnetron type sputtering apparatus 1 explained in the above embodiment has a cathode 12 connected to a wafer holder 1.
Although the cathode 12 is rotatably provided around the perpendicular line PL passing through the center of the wafer 71 held in the wafer 5, the cathode 12 may be rotated around the perpendicular line PL as shown in FIG.

That is, the sputtering chamber 11 is provided with a driving section 31 whose revolution axis coincides with a perpendicular line PL passing through the center of the wafer 71 held by the wafer holder 15. The drive unit 31 includes, for example, a normal planetary gear device 32 and a motor 33 that drives the planetary gear device 32. The planetary gear device 32 includes a sun gear 34, an internal gear 35 disposed outside the sun gear 34, and a planetary gear meshed with both the sun gear 34 and the internal gear 35 and provided between the sun gear 34 and the internal gear 35. 36, and an arm 37 that rotatably connects the sun gear 34 and the planetary gear 36 together. Then, the sun gear 34 is attached to the drive shaft 38 of the motor 33, and the cathode 12 is attached to the planetary gear 36. Therefore, the cathode 12 revolves around the perpendicular line PL, for example in the direction of arrow C.

Even when the cathode 12 is revolved as described above, the diameter of the target 13 can be reduced to approximately 1/2, similarly to the magnetron type sputtering apparatus 1. Therefore, the amount of DC power applied to the cathode 12 can be reduced to approximately 1/4, and the amount of cooling water for cooling the target 13 can also be reduced to approximately 1/4. Furthermore, since the cathode 12 revolves, a magnetic field generated by a magnetic field generator (not shown) revolves around the wafer 71. Therefore, like the sputtered film formed using conventional equipment, the wafer 7
The thickness of the film formed in 1 becomes almost uniform.

[0019]

[Effects of the Invention] As explained above, according to the present invention,
A drive unit for rotating the cathode via a drive shaft was provided on the edge side of the cathode, and the axis of the drive shaft was aligned with the perpendicular line passing through the center of the wafer held in the wafer holder.
It becomes possible to form the target diameter to approximately 1/2 of the wafer diameter. Therefore, the amount of electric power applied to the target and the amount of cooling water used to cool the target can be significantly reduced. Therefore, energy and water can be saved. Further, since there is no need to tilt the wafer holder, the wafer can be attached to and removed from the wafer holder using a normal wafer transfer device.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an embodiment.

FIG. 2 is a schematic cross-sectional view of a sputtering apparatus with a tilted cathode.

FIG. 3 is an enlarged sectional view taken along line A-A in FIG. 2;

FIG. 4 is a schematic cross-sectional view of a sputtering device in which a cathode revolves.

FIG. 5 is a schematic cross-sectional view of a conventional example.

FIG. 6 is a schematic sectional view of a main part of another conventional example.

[Explanation of symbols]

1 Magnetron sputtering device 11 Sputtering chamber 12 Cathode 13 Target 14 Magnetic field generator 15 Wafer holder 16 Drive unit 17 Drive shaft 71 Wafer

Claims (1)

[Claims] 1. A magnetron-type sputtering apparatus that includes a cathode that is equipped with a magnetic field generator and a target on its upper surface, and a wafer holder that is placed above the target. 1. A magnetron sputtering apparatus, characterized in that a drive section for rotating the cathode is provided, and the axis of the drive shaft is substantially aligned with a perpendicular line passing through the center of the wafer held by the wafer holder.