JPH05243181A - Sputtering device - Google Patents

Abstract

PURPOSE:To provide a sputtering device provided with a collimator which enables only a vertical component of atoms emitted from a target to impinge on a substrate, where the sputtering device is used for forming a thin film on the substrate, a film attached to the collimator is prevented from separating from the collimator and attaching to the substrate, and a contact hole is well filled with the thin film. CONSTITUTION:Two films 1 where holes are provided corresponding to each other are arranged between a target 4 and a substrate 5, a film feed mechanism 2 which feeds the films 1 so as to make holes provided to the films 1 correspond to each other, and a film take-up mechanism 3 are provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sputtering apparatus for forming a thin film on a substrate.

[0002]

2. Description of the Related Art Aluminum alloys, tungsten, etc. are used as wiring materials for semiconductor integrated circuits. These metal films are often formed using a sputtering method.

However, as shown in FIG. 4, irregularities such as a step 15 and a contact hole 16 are usually present on the semiconductor substrate 14. When the wiring 17 made of aluminum or the like is formed by using the normal sputtering method, as shown in FIG. 4, the aluminum film in the step portion 15 and the contact hole portion 16 is formed.
The coverage of 17 becomes insufficient, the current density increases in these regions, and disconnection or the like due to electromigration may occur.

Several contact hole burying techniques have been proposed in order to solve such problems.
One of them is a method of filling the contact hole with tungsten by the selective CVD method. Although this method is a simple process, selectivity is not always certain. Further, when the metal exposed at the bottom of the contact hole is aluminum, the tungsten hexafluoride (WF ₆ ) gas used for selective growth of tungsten by the CVD method reacts with the aluminum, and the aluminum surface has 3 fluorine. A film of aluminum fluoride (AlF ₃ ) is formed, making it difficult to make electrical contact. Therefore, prior to the growth of the interlayer insulating film 18, it is necessary to form a film of tungsten or the like on the aluminum surface by using the sputtering method. As another method, there is a method in which a blanket tungsten layer is formed on the interlayer insulating film 18 including the inside of the contact hole 16 and the tungsten layer is removed by etching from a region excluding the contact hole. This method is a reliable method although the process is complicated. However, since the blanket tungsten layer formed by the CVD method has poor adhesion to the oxide film, an adhesion layer such as a titanium-tungsten (Ti-W) film is previously formed on the interlayer insulating film 18 by using the sputtering method. However, there is a drawback that the process cost is increased.

Therefore, there is a demand for a technique for filling contact holes by using a sputtering method capable of forming a film having relatively good adhesion. In the sputtering method, the atoms that fly out from the target due to the collision of ions follow the so-called cosine law, so the target atoms are incident and deposited on the substrate from all directions. Therefore, as shown in FIG. 4, the atomic flux incident on the interlayer insulating film 18 surrounding the contact hole 16 is larger than the atomic flux incident on the bottom portion / side portion of the contact hole 16. Furthermore, the atomic flux that should be incident on the bottom and sides during growth is the interlayer insulating film that surrounds the contact hole 16.
As it is shadowed by the film grown on 18,
The film thickness that grows on the bottom and sides becomes thinner.

In order to make the amount of atomic flux reaching the bottom of the contact hole and the flat part of the substrate the same, it is necessary to remove components other than the flux perpendicular to the substrate out of the atomic flux that jumps out of the target and reaches the substrate. Good. Rossnagel 〔J. Vac. Sci. Technol. A9 (2) 261
(1991)] et al., As shown in FIG.
It has been announced that the contact hole is filled when a thin film is formed only by the vertical component by providing the collimator 11 between the substrate 2 and the substrate 13. Note that they have proposed a method of moving the substrate to prevent shadowing by the collimator itself.

[0007]

In the method of Rossnagel et al., The atoms flying from the target 12 constantly grow in the collimator 11. Therefore, when this method is applied to a so-called single-wafer sputtering apparatus, the collimator 11 is thick. A film is formed and the shape of the collimator 11 changes. Furthermore, when forming a film with relatively poor adhesion such as tungsten,
The film adhering to the collimator 11 is peeled off, which adheres on the substrate 13 and causes a decrease in yield and reliability of the semiconductor device formed on the substrate.

An object of the present invention is to eliminate these drawbacks, and has a collimator that allows only vertical components of atoms flying from a target to be incident on the substrate, and the film attached to this collimator peels off onto the substrate. It is an object of the present invention to provide a sputtering apparatus that can satisfactorily fill a contact hole without sticking to the surface.

[0009]

The above object is to provide at least two films (1) each having a corresponding hole between a target (4) and a substrate (5). A film supply mechanism (2) and a film storage mechanism (3) for moving the at least two films (1) so that the holes formed in each of the films correspond to each other. It is achieved by a sputtering device. The film (1) is preferably an aluminum film, an aluminum alloy film or a polyimide film.

[0010]

As shown in FIG. 1, at least two, and in the figure, three film-like collimators 1 are arranged between the target 4 and the substrate 5. As shown in FIG. 2, for example, a hole having a diameter of 5 mm is formed on each of the films by 10 m.
If the film is formed in a grid pattern with a pitch of m and the distance between the films is 15 mm, performance almost equivalent to that of a collimator with an aspect ratio of 6 can be obtained. If the film-like collimator 1 is grown by sputtering while continuously moving in synchronization with the holes formed in each film so as to correspond to each other, the amount of target atoms deposited on the collimator 1 is significantly reduced. . Therefore, unlike the conventional case, the deposit is not separated from the collimator, and the contact hole can be satisfactorily filled even in the single-wafer sputtering apparatus.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sputtering apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a view of a sputtering chamber of a single-wafer type magnetron sputtering apparatus as viewed from above. Reference numeral 8 denotes a vacuum chamber having an argon gas inlet, and although not shown in the figure, a vacuum exhaust system is connected to the lower part. Reference numeral 4 denotes a tungsten target having a diameter of 200 mm and a thickness of 10 mm, which is joined to a backing plate 7 cooled by cooling water with indium-based solder. Reference numeral 9 is a magnet for magnetron sputtering. 5 is the diameter at which the thin film is formed 1
The substrate is a 00 mm substrate, is fixed to a wafer chuck 6 having a heating means, and is held parallel to the target 4 during sputter growth. The substrate transfer mechanism is omitted in FIG. Reference numeral 1 is a collimator film according to the gist of the present invention, 2 is a collimator supply mechanism for supplying the collimator film 1, and 3 is a collimator storage mechanism for winding the collimator film 1. The collimator film 1 is composed of three aluminum films each having a width of 225 mm and a thickness of 15 μm, and as shown in FIG. 2, holes having a diameter of 5 mm are formed in a grid pattern with a pitch of 10 mm. The aluminum film wound by a roller having a length of 100 m is loaded into the collimator supply mechanism 2. The rollers of the collimator storage mechanism 3 can wind the collimator film 1 at a constant speed that can be arbitrarily set by a drive mechanism provided on the atmosphere side through vacuum rotation introduction. Three
The collimator films 1 are kept at a distance of 15 mm from each other in the area facing the target 4, and the holes formed in the film are moved so as to correspond to each other.

When the sputtering was carried out at a sputtering power of 5 kW, a sputtering gas pressure of 1.5 mTorr and a substrate temperature of 300 ° C., a collimator moving speed of 1 mm / sec was appropriate. Further, in the case of this sputter power, 0.5 μm
It took 100 seconds to grow a thick tungsten film. Therefore, when a 100 m long collimator film is used, it is possible to grow a tungsten film on 1000 substrates.

Further, using this device, the diameter is 0.8 μm.
I was able to almost completely fill the contact hole. The particle density on the substrate is 0.2 μm.
It was confirmed that the number of particles was 50 or less, which was the same as when the collimator was not used, that is, the state before the contact hole was filled, and that the use of the collimator did not cause contamination.

Although an aluminum film is used as the collimator film in this example, a heat-resistant film such as polyimide, which is an insulator, can be used. Collimator film 1 on the front of target 4
Since a metal film grows in the vacuum chamber, if the rollers of the collimator supply mechanism 2 and the storage mechanism 3 in contact with the collimator film 1 are grounded to the vacuum chamber 8, the collimator film effectively functions as an anode for magnetron discharge. .

[0016]

As described above, in the sputtering apparatus according to the present invention, at least two film-like collimators having holes corresponding to each other are arranged between the target and the substrate, Since the sputtering is carried out while continuously moving this, only the vertical component of the atomic flux from the target is supplied to the substrate, and the amount of target atoms adhering to the collimator is reduced so that delamination does not occur. It became possible to satisfactorily embed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a sputtering apparatus having a collimator according to the present invention.

FIG. 2 is a diagram showing an example of dimensions of holes formed in a film collimator.

FIG. 3 is a diagram illustrating the principle of a conventional collimator sputtering method.

FIG. 4 is a diagram showing the coverage of an aluminum film grown by a conventional sputtering method.

[Explanation of symbols]

 1 film collimator 2 collimator supply mechanism 3 collimator storage mechanism 4 target 5 substrate 6 wafer chuck 7 backing plate 8 vacuum chamber 9 magnet 11 collimator 12 target 13/14 substrate 15 step 16 contact hole 17 aluminum wiring 18 interlayer insulation film

Claims (2)

[Claims] 1. At least two films (1) each having holes corresponding to each other are provided between a target (4) and a substrate (5), and the at least two films (1). ) Is moved so that the holes formed in each of the films correspond to each other, a film supply mechanism (2) and a film storage mechanism (3)
And a sputtering apparatus. 2. The sputtering apparatus according to claim 1, wherein the film (1) is an aluminum film, an aluminum alloy film or a polyimide film.