JPH07157876A - Thin film forming device and ion-beam sputtering device - Google Patents

Abstract

PURPOSE:To provide a film forming device capable of increasing the amt. of thin film to be formed on the side wall and bottom at the time of forming a stepped film or a wiring film in the contact hole of a semiconductor device. CONSTITUTION:An ion-beam sputtering device consisting of a vacuum chamber 1, ion source 2, leader electrode 13, target 9, substrate holder 5, substrate 7, etc., is used to form a film on a stepped part or in a contact hole. The ion source 2 takes a turn around the substrate holder 5 so that the target 9 is irradiated with the drawn out ion beam, and a film is formed in the contact hole. Consequently, the amt. of film to be formed on the stepped part and the side wall and bottom of the contact hole is increased, and the film forming rate is increased in ion-beam sputtering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus and an ion beam sputtering apparatus, and more particularly, to a thin film forming apparatus and an ion beam sputtering apparatus suitable for forming a stepped portion such as a contact hole in forming a semiconductor element. Regarding

[0002]

2. Description of the Related Art There are several types of thin film forming apparatuses, one of which is a sputtering apparatus. In particular, a magnetron sputtering apparatus has a higher film forming speed than a conventional type apparatus. It is also used for production.

By the way, a substrate on which a thin film is formed is usually flat. However, a film is formed once, and as shown in FIG. 2, the film is made uneven, and after forming a contact hole of a semiconductor element, the hole is formed. A wiring film may be formed on the part. Conventionally, a film is also formed on the uneven step portion, bottom portion, or contact hole portion using a magnetron sputtering device.

In order to form a semiconductor element, an insulating film and a wiring film are formed in multiple layers.
For example, for forming aluminum film, a magnetron sputtering apparatus has been conventionally used.

A magnetron sputtering apparatus is disclosed in Japanese Patent Laid-Open No. 147063/1991.

[0006]

In the conventional magnetron sputtering method, when a thin film is to be formed on the step portion or the contact hole portion, the side wall of the step portion or the contact hole portion is compared with the film thickness deposited on the flat portion. However, there is a problem that the film thickness attached to the bottom is smaller than the film thickness attached to the flat part.

The present invention has been made in view of the above points,
The purpose thereof is to make the film thickness deposited on the step portion, the side wall of the contact hole portion, and the bottom portion larger than the conventionally obtained value.

[0008]

In order to achieve the above object, the present invention employs a means using an ion beam sputtering apparatus capable of forming a film in a high vacuum. Further, the substrate holder of the ion beam sputtering apparatus is made swingable so that the arrival efficiency of the sputtered particles to the step portion and the side wall portion of the hole portion is improved. Further, in order to increase the film forming speed of the ion beam sputtering, a cylindrical ion source is arranged on the outer peripheral portion of the substrate holder.

[0009]

The ion beam sputtering apparatus can form a film in a high vacuum as compared with the magnetron sputtering apparatus, so that the sputtered particles jumping from the target are directed to the substrate with good directivity. For this reason, the sputtered particles easily reach the bottom of the step portion and the bottom of the contact hole, and the film thickness in that region becomes thicker than that of the conventional device. Further, by swinging the substrate holder, the side wall can be directed toward the target, the number of sputtered particles flying to the side wall increases, and the film thickness on this part can be increased. In ion beam sputtering, by disposing a cylindrical ion source on the outer peripheral portion of the substrate holder, the extraction area of the ion beam is increased, and the action of irradiating the target with a large amount of the ion beam can increase the film formation rate.

[0010]

The present invention will be described below based on the illustrated embodiments.

FIG. 1 shows an embodiment of the present invention. FIG. 1 shows the configuration of an ion beam sputtering apparatus. As shown in the figure, a vacuum chamber 1 is connected to a vacuum exhaust system 4 via an ion source 2 and a gate valve 3.
Inside the substrate, a target 9 made of a material to be deposited is arranged on a substrate holder 5 supporting a substrate 7 and a target holder 8. The substrate holder 5 can be rotated by a drive mechanism 6, and the target holder 8 is water-cooled to cool the target 9.

A filament 10 is arranged inside the ion source 2, and a mass flow meter 11 for controlling the gas flow rate and a cylinder 12 filled with an inert gas such as argon (Ar) are connected. At the connecting portion between the ion source 2 and the vacuum chamber 1, an extraction electrode 13 composed of two or three sheets having a large number of holes is arranged. Reference numeral 14 is a neutralizer for neutralizing the ions extracted from the extraction electrode 13, and emits thermoelectrons.

Next, the operation of the present invention will be described.

After mounting the target 9 on the target holder 8 and disposing the substrate 7, the interiors of the vacuum chamber 1 and the ion source 2 are evacuated to a high vacuum by the vacuum evacuation system 4. Then, Ar gas is supplied from the cylinder 12 through the mass flow meter 11 at a constant amount, for example, several CCs per minute.

Next, an electric current is applied to the filament 10 to connect a power source (not shown) to the wall of the ion source 2 to cause arc discharge. The inside of the ion source 2 is in a plasma state in which Ar ions Ar + and electrons are mixed, and Ar + extracted by the electric field from the extraction electrode 13 is set to an arbitrary value between several hundred eV and 1500 eV, for example. The target 9 is irradiated with energy. The material of the target 9 is ejected from the target 9 as the sputtered particles 15 to reach the substrate 7 by the sputtering action.

Ion beam sputtering is capable of forming a film in a high vacuum (for example, 10 ⁻³ Pa) as compared with conventional magnetron sputtering. Therefore, sputtered particles in the vacuum chamber 1 before the substrate 7 arrives. There is almost no collision with gas and it flies with good directivity. Therefore, even if the film formed on the substrate shown in FIG. 2 has a step (16-a) or a contact hole (16-b), the bottom of the step is further formed when a thin film is further formed on these substrates. , Sputtered particles also reach the bottom of the pinhole.

This state is shown in FIG. FIG. 6 is an enlarged view of the contact hole portion 16-b of FIG. 2, and the sputtered particles reaching the hole portion form a film indicated by 17. Here, when the film thicknesses attached to the upper part (lower side in the figure) of the contact hole, the step part, and the bottom part are a, b, and c, b / a, c /
Both a are smaller than 1.

When a wiring film, such as an aluminum film, is formed in such a hole portion, the thickness of the film attached to the step portion and the bottom portion is smaller than the value attached to the upper portion of the pinhole, and particularly in conventional magnetron sputtering. The ratio b / a, c /
a was small.

On the contrary, when the ion beam sputtering shown in FIG. 1 was used, it was found that b / a and c / a were significantly increased as a result of the experiment.

In the case of a wiring film, the minimum value of the thickness of the wiring film formed on the step and bottom of the contact hole is determined by the current-carrying capacity, etc. Therefore, the larger b / a and c / a are, It can be said that it can be used efficiently. Since ion beam sputtering has a larger value than conventional magnetron sputtering, it is a very suitable method for forming a film on a contact hole.

FIG. 3 shows a different embodiment, in which the substrate holder 5
The angle formed by the target 9 and the target 9 changes with time, that is, a swinging mechanism is provided and rotation is possible.

In the case of this embodiment, a large amount of sputtered particles can fly to the wall portion of the step and contact hole shown in FIG. 2, and it is particularly effective in increasing the film formation amount on the wall portion. As described with reference to FIG. 6, it is effective to increase the value of b / a.

FIG. 4 shows a further different embodiment, in which the target holder 8, the target 9, the substrate holder 5 and the substrate 7 are arranged inside the vacuum chamber 1 as in the case of FIG. 2 is different in that it has a structure in which the substrate 2 surrounds the substrate holder 5 and makes one round. The ion source configured to make one round may be configured by disposing a plurality of divided ion sources.

In this ion beam sputtering, the extraction area of the ion beam can be made significantly larger than that of the conventional one. Therefore, a large amount of the ion beam is applied to the target 9,
The film forming speed can be increased.

By applying the ion beam sputtering apparatus to the film formation on the contact hole portion, there is an effect that the film formation amount on the bottom portion and the side wall portion of the contact hole can be increased and the film formation speed can be increased. Although not shown in FIG. 4,
A mechanism that allows the substrate holder to rotate and further swing can be added, and in this case also, there is an effect that the amount of film formation on the side wall can be increased.

FIG. 5 shows a further different embodiment, in which the substrate holder 5 and the substrate 7 are arranged inside the vacuum chamber 1, and the ion source 2 is arranged so as to go around the substrate holder 5 once. The target 9 is arranged in a conical shape inside the vacuum chamber 1. Alternatively, a plurality of targets composed of planes may be arranged in a V shape.

The ion beam of Ar extracted from the ion source 2 irradiates the target 9, and the particles sputtered by this are deposited as sputtered particles on the substrate 7 on the substrate 7.

As a configuration of the ion source and the target, a plurality of ion sources may be arranged around the substrate holder, and the same number of targets may be arranged at positions facing the ion source so that the sputtered particles reach the substrate. Good. In the ion beam sputtering apparatus having this configuration, the target area can be widened, a large amount of ion beam can be applied to the target, and the film formation speed can be increased. Further, some of the sputtered particles fly to the facing target, which has the effect of reducing the consumption of the target.

When the ion beam sputtering apparatus of this structure is used for forming a film on a step portion or a contact hole portion, sputtered particles fly over the entire circumference of the side wall portion.
In particular, it is effective to increase the efficiency of film deposition on the side wall.
Also in the configuration of FIG. 5, the substrate holder 5 can be swung or can rotate, and a larger amount of film can be formed on the bottom and side walls of the contact hole than in the conventional device. In addition, by using these ion beam sputtering devices to form a film on the contact hole portion, there is an effect that the film forming speed can be increased and the film on the side wall portion and the bottom portion can be thickened. When the target is arranged in a conical shape, sputtered particles fly to the side wall from all directions, so that the film in this portion can be thickened.

[0030]

According to the present invention described above, by using an ion beam sputtering apparatus in which sputtered particles fly with a good directivity, the film thickness on the step portion or the side wall portion to the contact hole of the semiconductor element and the bottom portion Can be made thicker than the conventional device, which is very effective in forming a semiconductor element, for example. In addition, by swinging or rotating the substrate holder, there is an effect that the amount of film formed on the film forming portion on the side wall can be increased.

Further, in the ion beam sputtering apparatus, the ion source is formed so as to surround the substrate holder so that a large amount of ion beam can be generated, and the film forming speed can be significantly increased as compared with the conventional case. effective.

By arranging the targets in a conical shape with the ion source having the same structure, there is an effect that the target area is widened and the film formation speed can be greatly increased.

[Brief description of drawings]

FIG. 1 is a sectional view of an ion beam sputtering apparatus showing an embodiment of the present invention.

FIG. 2 is a sectional view illustrating a substrate unique to the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the present invention.

FIG. 6 is a partial cross-sectional view showing a hole portion of FIG. 2 in an enlarged manner.

[Explanation of symbols]

1 ... Vacuum chamber, 2 ... Ion source, 3 ... Gate valve, 4 ...
Vacuum evacuation system, 5 ... Substrate holder, 6 ... Driving mechanism, 7 ... Substrate, 8 ... Target holder, 9 ... Target, 10 ... Filament, 13 ... Extraction electrode, 16-b ... Contact hole, 17 ... Membrane.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Kaneko 882 Ichige, Katsuta City, Ibaraki Prefecture Hitachi Ltd. Measuring Instruments Division

Claims (8)

[Claims] 1. A cross section of a thin film formed on a substrate has a step or a hole such as a contact hole, and a means for forming a further thin film on the thin film is provided in a vacuum chamber and in the vacuum chamber. Supported target, a substrate holder for supporting a substrate on which thin particles are formed by particles sputtered by sputtering the target, and an ion for the target supported by the vacuum chamber for sputtering the target. A thin film forming apparatus, which is an ion beam sputtering apparatus including an ion source for irradiating a beam. 2. The thin film forming apparatus according to claim 1, wherein the substrate holder is an ion beam sputtering apparatus that swings and / or rotates about a target. 3. A vacuum chamber, a target provided in the vacuum chamber, a substrate holder for supporting a substrate on which a thin film is formed by adhering particles ejected by sputtering the target, and the vacuum chamber. And an ion source for irradiating the target with an ion beam in order to sputter the target. An ion beam sputtering apparatus comprising: an ion source for irradiating the target with an ion beam; Alternatively, there is a thin film in which a contact hole is formed, and a further thin film is formed on the thin film by adhering particles that fly out by sputtering the target, and an ion beam sputtering apparatus. 4. The thin film forming apparatus according to claim 3, wherein the substrate holder is an ion beam sputtering apparatus that swings and / or rotates about a target. 5. A vacuum chamber, a target provided in the vacuum chamber, a substrate holder for supporting a substrate on which a thin film is formed by adhering particles ejected by sputtering the target, and the vacuum chamber. In an ion beam sputtering apparatus comprising an ion source for irradiating the target with an ion beam to sputter the target, in an outer peripheral portion of the substrate holder inside the vacuum chamber,
An ion source that surrounds the substrate holder is arranged so as to surround the substrate holder, and a target arranged opposite to the substrate is irradiated with the ion beam extracted from the ion source. There is a thin film in which a step or contact hole is formed in the cross section by applying an appropriate treatment, and it is possible to form a further thin film on the thin film by attaching particles that have jumped out by sputtering the target. Characteristic ion beam sputtering equipment. 6. The ion beam sputtering apparatus according to claim 5, wherein the ion source which surrounds the substrate holder and makes a round comprises a plurality of divided ion sources. 7. The ion beam sputtering apparatus according to claim 5, wherein the substrate holder swings or rotates about a target. 8. A vacuum chamber, a target provided in the vacuum chamber, a substrate holder for supporting a substrate on which a thin film is formed by adhering particles ejected by sputtering the target, and the vacuum chamber. In an ion beam sputtering apparatus comprising an ion source for irradiating the target with an ion beam to sputter the target, in an outer peripheral portion of the substrate holder inside the vacuum chamber,
An ion source is arranged so as to encircle the substrate holder, and a target arranged facing the substrate has a conical shape.
Alternatively, the thin film has a V-shape formed of a large number of planes, and there is a thin film having a step or a contact hole formed in its cross section on the substrate from the beginning or by performing an appropriate treatment. An ion beam sputtering apparatus characterized in that a further thin film is formed on the thin film by adhering the particles that have jumped out.