JPH07150347A - Sputtering device having collimator - Google Patents

Abstract

PURPOSE:To deal with a change in an aspect ratio occurring in adhesion of sputtered particles in apertures during film formation by forming a collimator to a structure in which two pieces of members fit freely vertically movably to each other and varying the length of the apertures. CONSTITUTION:The collimator 7 installed between a target material and semiconductor substrate 4 in a vacuum vessel 1 is composed of first and second collimating members 5 and 6. The apertures 17 of the collimator 7 are formed by cylindrical parts 15 of the second collimating member 6 fitted and inserted into the many cylindrical parts 15 of the first collimating member 5. The first collimating member 5 is fixed and the second collimating member 6 is vertically moved via bellows 23 by using a motor 18 outside the vacuum vessel 1 to put the cylindrical parts 16 in and out, by which the length of the apertures of the collimator 7 is changed and the prescribed aspect ratio is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering device having a collimator.

[0002]

2. Description of the Related Art As the degree of integration of a semiconductor integrated circuit device increases, the diameter of a contact hole 33 formed in an insulating film on the main surface of a semiconductor substrate 4 shown in FIG.
It becomes fine with m. Then, a barrier metal film 31 and a wiring film 32 are formed here by a sputtering apparatus, but the directions of the sputtered particles are not constant and are scattered in various directions.
The bottom coverage ratio defined by (thickness b at the bottom of the contact hole) / (thickness a at the surface) becomes low, and the thickness b at the bottom of the contact hole 33 becomes small, so that the contact resistance of the wiring becomes large. I will end up. If the contact resistance is large, the power consumption of the integrated circuit increases and the processing speed becomes slow.

In order to solve this problem, a collimator for eliminating sputtered particles scattered in an oblique direction out of sputtered particles scattered from the target material is arranged between the target material and the semiconductor substrate as shown in FIG. Such a sputtering device is disclosed in, for example, Japanese Patent Laid-Open No. 1-116070.

That is, in FIG. 4, a semiconductor substrate 4 and a target 3 are arranged in a vacuum processing chamber 1 which is evacuated by a vacuum pump 2, and a collimator 11 having a large number of openings 12 is arranged between them. . Among the sputtered particles 8 scattered from the target 3 in various directions, the oblique sputtered particles 9 obliquely scattered do not adhere to the inner wall of the opening 12 of the collimator 11 and reach the semiconductor substrate 4. On the other hand, the vertically sputtered particles 10 scattered in the vertical direction pass through the openings 12 of the collimator 11 and reach the semiconductor substrate 4. By disposing the collimator 11 in this way, a film is formed by the vertically sputtered particles 10,
The bottom film thickness of the contact hole and the surface film thickness can be made substantially equal.

[0005]

However, in the above technique, as the film formation progresses, the diameter x of the opening portion becomes narrower due to the sputtered particles adhering to the inner wall of the opening portion 12 (the depth y of the opening portion). The aspect ratio of the opening 12 defined by / (diameter x of the opening) changes. If the aspect ratio changes, the film forming conditions change, and if it is necessary to perform the film forming from the film forming start to the film forming completion under the same condition, it becomes impossible.

Alternatively, if the number of times of film formation processing is repeated, the aspect ratio changes for the above reason, and it becomes impossible to set the film formation operation under a predetermined film formation condition.

On the other hand, on the contrary, when it is necessary to change the film forming conditions on the way, the aspect ratio A (y) shown in FIG.
_The collimator 11 ′ having a ratio of 1 / x) to the collimator 1 having a predetermined aspect ratio B (y ₂ / x) shown in FIG.
Although it has to be changed to 1 ″, this predetermined change cannot be easily made in the conventional sputtering apparatus.

In the prior art, it is necessary to break the vacuum, that is, to return the inside of the vacuum processing chamber from the vacuum state to the atmospheric state in order to remove the inconvenience and change the collimation. However, when the atmosphere is returned to the atmosphere in this way, the sputtered film adhered to the inner wall of the vacuum processing chamber is peeled off and the semiconductor substrate is adversely affected when it is processed later.

In addition, it takes about one hour to break the vacuum in the vacuum processing chamber and evacuate the vacuum chamber to a desired degree of vacuum again, including the collimator replacement work, and the man-hours are wasted.

[0010]

The feature of the present invention is that the sputter particles scattered from the target material are disposed between the target material and the semiconductor substrate so as to exclude sputter particles scattered in an oblique direction. In the sputter device having a collimator, the collimator is a sputter device having a collimator in which the depth of the collimator opening can be changed by combining the first collimator member and the second collimator member. Here, the collimating aperture portion is composed of a cylindrical portion of the first collimating member and a cylindrical portion of the second collimating member inserted therein, and the collimating opening portion is formed by inserting and removing the both cylindrical portions. The depth of can be changed. Further, the target material, the semiconductor substrate, and the first and second collimating members are arranged in a vacuum processing chamber, a driving means is arranged outside the vacuum processing chamber, and the driving means is arranged to be the first means via a vacuum bellows. And one of the second collimating members.

[0011]

The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing a sputtering apparatus according to an embodiment of the present invention. The vacuum processing chamber 1 is evacuated to a high vacuum by a vacuum pump 2, a sputtering gas is introduced, and a high voltage is applied between the target 3 and the semiconductor substrate 4 as an anode, thereby performing sputtering.

The vertically sputtered particles 10 are predominantly placed on the semiconductor substrate 4 by disposing the obliquely sputtered particles 9 (FIG. 4) among the sputtered particles 8 scattered from the target 3 which are arranged between the target 3 and the semiconductor substrate 4. The collimator 7 of this embodiment for sputtering and film-forming on it is composed of a first collimator member 5 and a second collimator member 6, and is provided with a large number of cylindrical portions 15 of the first collimator member 5. A large number of apertures 17 of the collimator 7 are formed by the cylindrical portion 16 of the second collimating member 6 inserted into each of them, and the depth of the collimator opening 17 is formed by taking in and out both the cylindrical portions 15 and 16. The aspect ratio is changed by changing y.

That is, by fixing the first collimating member 5 and drivingly adjusting the second collimating member 6 in the vertical direction in the figure, the depth y of the opening 17 of the collimator 7 is adjusted, 2 (A) state aspect ratio A (y ₁ /
x) is the aspect ratio B (y ₂ / x) in the state of FIG.
Change while maintaining the vacuum state.

This driving is performed by using a motor 18 and moving a screw shaft 22 coupled to the second collimating member 6 up and down through a pinion 19, a first gear 20, and a second gear 21. This drive unit is provided on the outside of the vacuum processing chamber 1 on the atmosphere side in order to prevent dust generation inside the vacuum processing chamber 1.
A plurality of vacuum bellows 23 are installed along the outer periphery of the collimating member 6 at equal intervals, and the up and down moving parts connect the second collimating member 6 and the envelope of the vacuum processing chamber 1 to each other. Isolate the vacuum from the atmosphere.

FIG. 2 is a sectional view showing a state of the opening 17 of the collimator 7 formed by combining the first and second collimating members 5 and 6, and FIG. 3 is a sectional perspective view thereof.

2 (A) and 3 (A) show the case in which the second collimating member 6 is raised the most, the cylindrical portion 15 of the first collimating member 5 and the cylindrical shape of the second collimating member 6 are shown. The part 16 and the first part 2 are overlapped with each other.
The depth y ₁ of the opening portion 17 of the collimator 7 formed by the collimator members 5 and 6 becomes minimum and the aspect ratio y ₁ /
x becomes the minimum. On the other hand, FIGS. 2 (B) and 3 (B) show the case where the second collimating member 6 is lowered most, and the height of the lower end of the cylindrical portion 15 of the first collimating member 5 and the second collimating member 6 are the same. The heights of the upper ends of the cylindrical portions 16 of the first and second collimating members 5, 5 become the same.
The depth y ₂ of the aperture 17 of the collimator 7 made of 6 becomes maximum, and the aspect ratio y ₂ / x becomes maximum.

Even when the film formation progresses and sputtered particles adhere to the inside of the opening to reduce the diameter x of the opening, the film formation is continued under a certain condition while maintaining a constant aspect ratio. 2B and FIG. 3B side, and gradually drive in the directions of FIG. 2A and FIG. 3A according to the progress of film formation to reduce y. All you have to do is go.

On the other hand, when it is necessary to change the film forming conditions on the way, it is necessary to change between the state shown in FIGS. 2A and 3A and the state shown in FIGS. 2B and 3B. It may be driven so as to be changed to a predetermined state between each time.

In any case, the depth y of the opening 17 of the collimator 7 can be adjusted while maintaining the vacuum inside the vacuum processing chamber 1.

In the above embodiment, the structure in which the upper first collimating member 5 is fixed and the lower second collimating member 6 is moved has been illustrated, but the upper first collimating member 5 is moved and the lower second collimating member 5 is moved. The second collimating member 6 may be fixed. Further, both collimating members 5 and 6 may be movable according to circumstances.

[0022]

As described above, according to the present invention, a collimator for forming a uniform film thickness on a height portion of a semiconductor substrate by vertically sputtered particles is constituted by a combination of two collimating members, and an opening portion thereof is formed. Since the depth of can be arbitrarily changed, it is possible to always maintain a constant aspect ratio against changes over time.

Further, there is an effect that different predetermined aspect ratios can be dealt with depending on the film forming conditions.

Further, since the aspect ratio can be maintained constant or the aspect ratio can be changed while the vacuum processing chamber is maintained in vacuum, dust due to peeling of the sputtered film adhering to the inner wall of the vacuum processing chamber can be eliminated. It is possible to prevent waste of man-hours without causing adverse effects.

[Brief description of drawings]

FIG. 1 is a sectional view showing an outline of a sputtering apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the operation of the collimator according to the embodiment of the present invention.

FIG. 3 is a sectional perspective view showing the operation of the collimator according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a conventional sputtering device.

FIG. 5 is a cross-sectional view illustrating a state in which a contact hole of a semiconductor substrate is formed by sputtering.

FIG. 6 is a sectional view showing a conventional collimator.

[Explanation of symbols]

 1 Vacuum Processing Chamber 2 Vacuum Pump 3 Target 4 Semiconductor Substrate 5 First Collimating Member 6 Second Collimating Member 7 Collimating 8 Sputtered Particles 9 Oblique Sputtering Particles 10 Vertical Sputtering Particles 11 (11 ′, 11 ″) Collimating 12 Collimating 11 Hole portion 15 of the first collimator member 5 cylindrical portion 16 second collimator member 6 cylindrical portion 17 collimator 7 hole portion 18 motor 19 pinion 20 first gear 21 second gear 22 shaft 23 Vacuum bellows 31 Barrier metal film 32 Wiring film 33 Contact hole

Claims (3)

[Claims] 1. A sputtering apparatus having a collimator arranged between a target material and a semiconductor substrate so as to exclude sputter particles scattered in an oblique direction out of sputter particles scattered from the target material. Is a sputtering apparatus having a collimator, characterized in that the depth of the collimating opening can be changed by combining the first collimating member and the second collimating member. 2. The collimating aperture portion is composed of a cylindrical portion of the first collimating member and a cylindrical portion of the second collimating member inserted into the collimating opening portion, and the collimator is formed by inserting and removing the both cylindrical portions. The sputtering apparatus having a collimator according to claim 1, wherein the depth of the opening is changed. 3. The target material, the semiconductor substrate, and the first and second collimating members are arranged in a vacuum processing chamber, driving means is arranged outside the vacuum processing chamber, and the driving means is arranged via a vacuum bellows. The sputtering apparatus having a collimator according to claim 1 or 2, which is coupled to one of the first and second collimating members.