JPS6326359A - Sputtering apparatus - Google Patents

Abstract

PURPOSE:To prevent the generation of coarse particles and to improve the uniformity of the thickness of a film formed by sputtering by placing a shielding body which covers peripheral parts of the surfaces of cathodes to be sputtered so as to prevent the deposition of particles on the peripheral parts. CONSTITUTION:Electric power is independently impressed to cathodes 1, 2 to generate plasma, this plasma is confined in a line of magnetic force and particles of the material of the cathodes 1, 2 are generated by sputtering. The particles reach a wafer 14 and forms a film. Before the electric power is supplied, a shielding body 11 which covers peripheral parts of the surfaces of the cathodes 1, 2 to be sputtered is placed so as to prevent the deposition of generated coarse particles on the peripheral parts.

Description

Detailed Description of the Invention -1= [Technical Field of the Invention] The present invention relates to a sputtering apparatus used for film formation in an LSI manufacturing process, and particularly to a sputtering apparatus using a conical link as a target.

[Technical Background of the Invention and Problems Therein] Formation of an alloy film on a semiconductor wafer usually requires a pressure of 10-Torr to 10''.
Argon plasma is generated by applying a voltage between the anode and the cathode (target) in argon gas at about Torr, and the argon plasma is drawn near the target by a magnetic field that is perpendicular to the electric field and surrounding the cathode. A high-speed sputtering method is used in which the target material is efficiently spun by argon ions and deposited on the wafer. This type of high-speed sputtering method uses planar mcnetron, coaxial magnetron, etc. depending on the electrode shape, and it is possible to form a metal film with strong adhesion strength without increasing the wafer temperature, and has excellent step coverage on wafer steps. It has characteristics. In particular, the sputtering device with a double cathode structure using a conical ring shown in FIGS. 3 and 4 has a sufficiently expanded erosion diameter of the outer target, so step coverage in the periphery of a large-diameter wafer is good and second Because the deposition is performed using a double ring plasma, the uniformity of the film thickness distribution is excellent, and the film thickness reproducibility is also good.

As shown in FIG. 4, this sputtering apparatus uses an inverted conical ring-shaped outer galley l-] and a disc-link-shaped inner target 2 located within its inner diameter as cathodes, and connects the inner target 2 and the outer galley I-i to each other as cathodes. Anno-! between Inner Target 2!・Install electromagnets 6 and 7, and install electromagnet 8 outside the outer target 1. Then, the electromagnet 6 and the electromagnet 8 have the same magnetic pole, and the electromagnet 7
have different magnetic poles, argon ions (plasma) are confined within the lines of magnetic force formed between the electromagnets 6 and 8, and the electromagnets 7, thereby striking the target material, which is the cathode. In addition, the wafer 14 is Targera 1.
-1.2 is applied to the heater table 15, and heated by the thermocouple 16 and the heater element 17. Further, the argon gas is heated through argon force or the argon inlet 18 and introduced from the rear surface of the wafer.

The sputtering apparatus configured in this manner has the excellent features described above, but includes an outer target 1, an inner target galley 1-2. In both cases, as shown by the dotted line in FIG. 5, the central portion is consumed compared to the peripheral portion. Therefore, the entire surface of the target is not used effectively.

Furthermore, when performing sputtering on a large number of semiconductor wafers, the sputtered film formed on the semiconductor wafers is not uniform, and particles that appear to be large in diameter begin to adhere.
This may have been used as a guideline for the lifespan of the Targera I-, or as mentioned above, a large amount of the surrounding area of the Targera I- (cathode) remained, and effective utilization was desired. As a result of the inventor's study of this phenomenon, the following was discovered. That is,
It was found that some of the particles ejected by the sputtering phenomenon by argon ions were deposited on the surrounding area of the target particle itself and on the surrounding areas of other adjacent target particles 1-, as shown by the dotted line in FIG. When the next sputtered argon ions collide with the surrounding areas where these sputtered particles have been deposited, these particles become large-diameter particles and are ejected, reaching the wafer and having an unfavorable effect on uniform film formation. It turned out that it was.

[Purpose of the Invention] The present invention has been made in view of the above-mentioned conventional difficulties, and provides a sputtering apparatus that prevents the generation of large-diameter particles and has excellent uniformity in the thickness of the sputtered film sputtered onto the wafer surface. This is what I am trying to do.

[Summary of the Invention] To achieve the above object, the sputtering apparatus of the present invention sputters the sputtering material by bombarding the cathode on which the sputtering material is provided with excited ions. The present invention is characterized in that a wind shield is provided to cover the periphery of the sputtering surface of the cathode, and the wind shield forms a wall that prevents particles from flying from one cathode to another cathode. Furthermore, the wind shield has a cover portion that prevents particles emitted from the cathode from being deposited near the wind shield.

[Embodiments of the Invention] Hereinafter, embodiments of the apparatus of the present invention will be explained in detail with reference to FIG.

The sputtering apparatus of this example has a double cathode structure including a substantially conical ring-shaped outer target galley l-1 and a disk ring-shaped inner target 2 located within the inner diameter of the outer target galley l-1. On the back side of each target 1.2 a cooling area 3.4 is provided, for example in which cooling water is circulated. A first electromagnet 5 is disposed within the inner diameter of the inner target 2, a ring-shaped second electromagnet 6 is disposed between the outer target 1 and the inner target 2, and a ring-shaped third electromagnet is disposed outside the outer circumference of the outer target galley l-2. electromagnets 7 are installed respectively. The first electromagnet 5 and the third electromagnet 7 are set to the same magnetic pole, and the second electromagnet 6 is set to a different magnetic pole, and both are magnetically shielded by a shield body 8.9.10 attached to the back side. .

Further, a wind shield 11 is attached to the second electromagnet 6 by screws or the like.

More fixed. As shown in FIG. 2, the wind shield 11 has a column part 12 for attaching to the electromagnet 6 and a cover part 13 having a generally doglegged cross section. Pillar part 12 and cover part 13
A part of the outer target] to the inner target 2
The outer target 1 forms a wall that prevents particles from flying from the inner target 2 to the outer target 1.

Further, the cover portion 3 prevents particles emitted from the outer target 1 from depositing on its peripheral portion 1a, and prevents particles emitted from the inner target 2 from depositing on its peripheral portion 2a. . In this case, the particles are deposited on the surface of the cover part 13. When plasma ions are input to the cathode material deposited on the surface of the cover part 13, this cathode material seems to be sputtered as in the case of the prior art, but the cover part 13 is moved away from the cathode surface and moved to a different position. Therefore, the magnetic field formed to confine plasma ions in the vicinity of the cathode surface hardly diffuses to the cover portion, or has weak energy, so a strong sputtering effect does not occur. Note that the pillar portion 12 and the cover portion 13 may be formed integrally. or,
The wind shield 11 is made of a conductor, and is electrically and magnetically
It is integrated with the electromagnet 6. Wafer 14 is Targera 1-1
．． It is set on a heater table 15 opposite to 2, and is heated to a constant temperature by a thermocouple and heater elements 1 to 1.

In the sputtering apparatus configured in this manner, independent power is applied to each cathode (outer target galley 1-1 and inner target 2) to generate double plasma, which is applied by the first electromagnetic force 5 and the second electromagnetic force 5. Confined within the lines of magnetic force generated between the electromagnet 6 and between the second electromagnet 6 and the third electromagnet 7, 1.2
Efficiently knocks out target material particles from the surface of the
Sputtering is performed on the second wafer 14 of the heater table 15. At this time, due to the presence of the wind shield 11, particles fly from the outer target 1 to the inner target plate 1 to 2, and from the inner target plates 1 to 2 to the outer target plate 1-1. This prevents particles from flying into the target area, and also prevents the particles knocked out from being deposited onto the peripheral parts 1a and 2a of each target layer 1-.

Note that the shape of the wind shield 11 is not limited to the shape of this embodiment, and can be arbitrarily changed within the scope of the claims.

[Effects of the Invention] As is clear from the above embodiments, in the sputtering apparatus of the present invention, particles are prevented from flying between the outer target and the inner target, and particles are prevented from flying into the periphery of both targets. Since the wind shield is provided with a structure that prevents the deposition of particles, the deposition of particles around the target and the accompanying generation of large-diameter particles are prevented. Therefore, only small-diameter particles ejected from the target surface by the plasma reach the wafer, making it possible to form a more uniform film.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the sputtering apparatus of the present invention, Fig. 2 is an enlarged view of the same main part, Figs. 3 and 4 are a front view and a sectional view of a conventional sputtering apparatus, respectively, and Fig. 5 is a diagram showing target wear. It is a figure showing a state. 1...Outer target galley 1-1a...Inner periphery 2...Inner target 2a...Outer periphery 3.4...Cooling area 5... ......First electromagnet 6...Second electromagnet 7...Third electromagnet 8.9.10...・・Shield body 11 ・・・・・ Wind shield 12 ・・・Column part (wall part) 13 ・・・・・
...Cover part 14 ...Wafer 15 ... Heater table representative Patent attorney Moritani -O Figure 3 Figure 4 Figure 1 Skin Gin 2 Figure 5 18゛ ``5 16 kan' m.

Claims (1)

[Scope of Claims] 1. In a sputtering apparatus that sputters the sputtering material by bombarding a cathode with a sputtering machine with excited ions, a shielding member is provided to cover the peripheral part of the sputtering surface of the cathode. A sputtering device characterized in that: 2. The sputtering device according to claim 1, wherein the shielding member forms a wall portion that prevents particles sputtered from the cathode from flying to the adjacent cathodes. Device. 3. The shielding body has a cover portion that prevents particles sputtered from the cathode from being deposited near the original cathode.
The sputtering apparatus according to item 1 or 2.