JPH021221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for forming a film by sputtering a target using ions.

(Prior Art) A method of forming a film using a sputtering phenomenon has been conventionally known. This will be explained with reference to FIG. First, from ion gun 1 to 500
A target 3 is irradiated with ions such as argon ions 2 emitted at an accelerating voltage of 1000V. At this time, sputtering is performed using argon ions 2, and the particles 4 constituting the target are ejected and deposited on the surface of the substrate 5, which is disposed facing the target 3 at a predetermined angle, thereby forming a film. However, since it is not possible to arrange the target and the substrate facing each other in parallel using such a film forming apparatus, the film deposition rate is high in the parts of the substrate that are close to the target, making it difficult to form a uniform film.

For this reason, Japanese Patent Publication No. 47-49987 discloses a method of using an ion beam deflection electrode to deflect the ion beam and irradiate the target. According to this method, sputtering and film deposition can be performed with the substrate placed parallel to and facing the target. However, in this method, since the ion beam is simply deflected and irradiated onto a predetermined region of the target using a deflection electrode, the film deposition rate increases only on the substrate region facing the sputtering region, depending on the directionality of the sputtered target particles. Therefore, there was a problem in that it was difficult to form a film with a uniform thickness. Moreover, since the erosion area formed by sputtering on the target is localized, there is a problem that the target becomes unusable in a short period of time.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems, and provides a film forming method that can deposit a film of uniform thickness and further improve target life. This is what I am trying to do.

[Structure of the Invention] (Means for Solving the Problems) The first invention of the present application irradiates a target with ions emitted from an ion gun, and forms a film on a substrate placed parallel to and facing the target. In the forming method, a plurality of the ion guns and electromagnets are arranged alternately on the same plane to form an annular body, and the annular body is arranged between the opposing target and the substrate, and the ion guns emitted from the ion guns are disposed between the target and the substrate. The ions deflected toward the target by the magnetic field of the electromagnet are irradiated, and at the same time, the current flowing through the coil of the electromagnet is changed while the ions are being irradiated onto the target, and the angle of ion deflection is changed over time so that different targets can be irradiated. This is a film forming method characterized in that target constituent particles sputtered from a region are deposited on the substrate.

A second invention of the present application is a method of irradiating a target with ions emitted from an ion gun and forming a film on a substrate placed parallel to and facing the target, in which the ion gun and the electromagnet are placed on the same plane. A plurality of ions are arranged alternately to form an annular body, and the annular body is arranged between the opposing target and the substrate, and the ions emitted from the ion gun are deflected toward the substrate by the magnetic field of the electromagnet. A step of cleaning the substrate surface by irradiating the target, deflecting the ions toward the target by the magnetic field of the electromagnet, and simultaneously changing the current flowing through the coil of the electromagnet while irradiating the target with ions, This film forming method comprises the step of depositing target constituent particles sputtered from different regions of the target on the substrate by changing the deflection angle over time.

A third invention of the present application provides a method for irradiating a target with ions emitted from an ion gun and forming a film on a substrate placed parallel to and facing the target, in which the ion gun and the electromagnet are placed on the same plane. A plurality of ions are arranged alternately to form a ring-shaped body, and the ring-shaped body is placed between the opposing target and the substrate, and the ions emitted from the ion gun are deflected toward the target by the magnetic field of the electromagnet and irradiated. At the same time, while the target is being irradiated with ions, the current flowing through the coil of the electromagnet is changed, and the deflection angle of the ions is changed over time, so that target constituent particles sputtered from different regions of the target are deposited on the substrate. and a step of deflecting and irradiating the ions toward the film on the substrate by the magnetic field of the electromagnet during film deposition.

(Operation) According to the first invention of the present application, in the method of irradiating a target with ions emitted from an ion gun and forming a film on a substrate disposed parallel to and facing the target, the ion gun and the electromagnet A plurality of ions are arranged alternately on the same plane to form a ring-shaped body, and the ring-shaped body is placed between the target and the substrate facing each other, and the ions emitted from the ion gun are directed to the target side by the magnetic field of the electromagnet. At the same time, while the target is being irradiated with ions, the current flowing through the coil of the electromagnet is changed, and the deflection angle of the ions is changed over time, so that the particles constituting the target sputtered from different regions of the target are By depositing it on a substrate, a film of uniform thickness can be formed. Moreover, by changing the deflection angle, the erosion area of the target can be expanded, and the life of the target can be improved.

According to the second aspect of the present invention, prior to film deposition on a substrate, ions emitted from an ion gun are deflected toward the substrate by the magnetic field of an electromagnet and irradiated, thereby cleaning the substrate surface uniformly. It is possible to form a film with a suitable thickness and improved adhesion strength and electrical contact resistance to the substrate. especially,
When applied to a device having a fine contact hole (1 μm or less), a film can be formed satisfactorily up to the inside of the contact hole.

Furthermore, according to the third aspect of the present invention, the ions emitted from the ion gun during film deposition are deflected and irradiated onto the film side on the substrate by the magnetic field of the electromagnet, thereby depositing the film with a uniform thickness and in a stepwise manner. Film formation with improved coverage can be performed. In particular, when applied to a device having a fine (1 to 2 μm) contact hole, the contact hole can be satisfactorily filled with a film. In this case, the ratio of film deposition rate to ion etching rate is 10~
A range of 50 is recommended.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example 1 In FIG. 1, a is a plan view of a film forming apparatus used in this example, and FIG. 1b is a sectional view taken along line BB in FIG. 1a. Reference numerals 11 ₁ to 11 ₆ in the figure indicate ion guns having an angle of, for example, 30 degrees and arranged in a ring with a pitch of 30 degrees. These ion guns 11 ₁ to 11 ₆ emit argon ions horizontally toward their centers. Moreover, each of the ion guns 11 ₁
An electromagnet with an angle of 30 degrees between 11 ₆ and 12 ₁
12 ₆ are placed. Such an ion gun 11 ₁
11 ₆ and electromagnets 12 ₁ to 12 ₆ form an annular body. A target 13 made of an aluminum-silicon alloy and having a diameter of 15 mm, for example, is arranged above the hollow portions of the ion guns 11 ₁ to 11 ₆ and the electromagnets 12 ₁ to 12 ₆ . Furthermore, below the hollow portions of the ion guns 11 ₁ to 11 ₆ and the electromagnets 12 ₁ to 12 ₆ , a support member 14 is disposed parallel to and opposite to the target 13 at a distance of 75 mm. These ion guns 11 ₁ to 11 ₆ and electromagnets 12
₁ to 12 ₆ , the target 13 and the support member 14 are placed in a vacuum container (not shown).

Next, a film forming method will be explained using the film forming apparatus described above.

First, a wafer 1 as a substrate is placed on the support member 14.
5 was fixed. Next, each ion gun 11 ₁ to 1
1 ₆ to emit argon ions with an accelerating voltage of 1000V, and at the same time, each electromagnet 1
2 ₁ to 12 ₆ are turned on and those electromagnets 12 ₁ to 1 are turned on.
The argon ions were deflected upward in a perpendicular direction by a magnetic field from ₂₆ and irradiated onto the target 13. Further, by changing the current flowing through the coils of each of the electromagnets 12 ₁ to 12 ₆ and changing the deflection angle of the argon ions, the area of the ions irradiated onto the target 13 was changed. By such irradiation with argon ions, aluminum alloy particles 16 were sputtered from the target 13, and an aluminum alloy film 17 was formed on the wafer 15 placed opposite the target 13.

When the thickness variation of the aluminum alloy film on the wafer was investigated, it was found to be 5%, confirming that an aluminum alloy film with a uniform thickness was formed. Further, by changing the deflection angle of the argon ions and changing the area of the ions irradiated onto the target 13,
The erosion area 18 was expanded, and the life of the target 13 could be extended by about 50% compared to the case where the irradiation area of the target with argon ions was not changed.

Example 2 First, the wafer 1 as a substrate is placed on the support member 14.
5 was fixed. Next, each ion gun 11 ₁ to 1
At the same time, applying an ion current to ₁₆ to emit argon ions with an accelerating voltage of 200V, each electromagnet 12
₁ to 12 ₆ are turned on and those electromagnets 12 ₁ to 12 ₆ are turned on.
The surface of the wafer 15 was cleaned by deflecting the argon ions in a downward right angle direction using a magnetic field and irradiating the wafer 15 with the argon ions. Subsequently, the ion current applied to each of the ion guns 11 ₁ to 11 ₆ is increased to emit argon ions with an acceleration voltage of 1000 V, and at the same time, the deflection direction of the argon ions is directed upward by the magnetic field from each of the electromagnets 12 ₁ to 12 ₆ . The target 13 was irradiated in a direction perpendicular to the target. In addition, each electromagnet 12
By changing the current flowing through the coils ₁ to 12 ₆ and changing the deflection angle of the argon ions, the area of the ions irradiated onto the target 13 was changed. By such irradiation with argon ions, aluminum alloy particles 16 are sputtered from the target 13, and an aluminum alloy film 1 is formed on the wafer 15 placed facing the target 13.
7 was formed.

When the thickness variation of the aluminum alloy film on the wafer was investigated, it was found to be 5%, confirming that an aluminum alloy film with a uniform thickness was formed. Furthermore, an aluminum alloy film with improved adhesion strength and electrical contact resistance to the wafer could be formed.

Example 3 First, the wafer 1 as a substrate is placed on the support member 14.
5 was fixed. Next, each ion gun 11 ₁ to 1
1 ₆ to emit argon ions with an accelerating voltage of 1000V, and at the same time, each electromagnet 1
2 ₁ to 12 ₆ are turned on and those electromagnets 12 ₁ to 12 6 are turned on.
The magnetic field from ₁₂₆ deflects the argon ions in an upward orthogonal direction to the target 13.
was irradiated. Further, by changing the current flowing through the coils of each of the electromagnets 12 ₁ to 12 ₆ and changing the deflection angle of the argon ions, the area of the ions irradiated onto the target 13 was changed. By this irradiation with argon ions, aluminum alloy particles 16 were sputtered from the target 13, and the aluminum alloy was deposited on the wafer 15 placed opposite the target 13. Subsequently, during the deposition of the aluminum alloy, the ion current applied to each ion gun 11 ₁ to 11 ₆ is lowered,
At the same time, argon ions with an accelerating voltage of 200 V are emitted, and the argon ions are deflected downward at right angles by the magnetic fields from the electromagnets 12 ₁ to 12 ₆ and irradiated onto the wafer 15, thereby removing the aluminum deposited on the surface of the wafer 15. An aluminum alloy film 17 was formed on the wafer 15 by periodically performing an etching operation to thin the alloy film.

When the thickness variation of the aluminum alloy film on the wafer was investigated, it was found to be 5%, confirming that an aluminum alloy film with a uniform thickness was formed. Furthermore, the step coverage of the aluminum alloy film deposited on the wafer has been dramatically improved.

In the above embodiment, film formation was performed using the film forming apparatus shown in FIGS. 1a and 2b, but the film forming apparatus shown in FIGS.
Film formation may be performed using the film forming apparatus shown in b. That is, 11 ₁ ' to 11 ₆ ' in the figure are, for example, 30
It is an ion gun arranged in a ring with a pitch of 30 degrees. These ion guns 11 ₁ ' to 11
₆ ' emits argon ions horizontally towards their center. Furthermore, electromagnets 12 ₁ to 12 ₆ having an angle of 30 degrees are arranged between the ion guns 11 _{1 ′} to 11 ₆ ′. The ion guns 11 ₁ to 11 ₆ and the electromagnets 12 ₁ to 12 ₆ form an annular body. The ion gun 11 ₁ ′~
Inside the hollow parts of 11 ₆ ' and electromagnets 12 ₁ to 12 ₆ ,
For example, a target 13 made of aluminum-silicon alloy and having a diameter of 15 mm is arranged. Furthermore,
An annular deflection plate 19 having an open upper surface and an inner circumferential surface is arranged below each of the ion guns 11 ₁ ′ to 11 ₆ ′. And each of the ion guns 11 ₁ ′ to 11
₆ ' and below the hollow parts of the electromagnets 12 ₁ to 12 ₆ ,
A support member 14 is disposed parallel to the target 13 and facing it at a distance of 75 mm. The ion guns 11 ₁ to 11 ₆ , the electromagnets 12 ₁ to 12 ₆ , the target 13, the support member 14, and the deflection plate 19 are arranged in a vacuum container (not shown).

To explain the method of forming a film using the above-mentioned apparatus, first, a wafer 15 as a substrate is fixed on the support member 14. Next, each ion gun 1
Applying ion current to 1 ₁ ′ to 11 ₆ ′ and accelerating voltage
At the same time as releasing 1000V argon ions,
Each electromagnet 12 ₁ to 12 ₆ is turned on. As a result, the argon ions are transferred to each of the electromagnets 12 ₁ to 12 ₆
and is deflected approximately 180 degrees by an annular deflection plate 19,
The target 13 is irradiated. Further, the current flowing through the coils of each of the electromagnets 12 ₁ to 12 ₆ is changed,
By changing the deflection angle of the argon ions, the area of the ions irradiated onto the target 13 was changed. By irradiating with these argon ions,
Aluminum alloy particles 16 from target 13
is sputtered, and an aluminum alloy film 17 is formed on the wafer 15 placed opposite the target 13. Also by this method, an aluminum alloy film having a uniform thickness can be formed as in the first embodiment described above. Further, as in Examples 2 and 3, cleaning of the wafer with argon ions and periodic irradiation of the wafer with argon ions during film deposition can be performed.

In the above embodiment, an electromagnet was used for ion deflection, but a superconducting magnet may be used to create an even stronger magnetic field.

In the above embodiment, a target made of an aluminum alloy was used, but the film may be formed using other materials such as quartz or a compound. When a target made of a non-conductive material such as quartz is used, when the target is irradiated with positive ions such as argon ions, the target becomes electrically charged. In such a case, charging can be prevented by irradiating the target with anions such as electrons at the same time as cations. In addition, when forming a film made of a compound, oxygen ions are used if the compound is an oxide, nitrogen ions are used if the compound is a nitride,
By using argon in combination, it is possible to match the stoichiometric ratio. Furthermore, during film formation, a gas for adjusting the stoichiometric ratio or a gas containing a doping substance into the deposited film may be introduced into the target surface or the space where sputter particles are scattered.

[Effects of the Invention] As detailed above, according to the first invention of the present application, it is possible to provide a film forming method that allows film deposition of uniform thickness and further improves target life. Further, according to the second invention of the present application, it is possible to provide a film forming method that enables film deposition of uniform thickness, improves target life, and improves adhesion strength to a substrate and electrical contact resistance. Furthermore, according to the third aspect of the present invention, it is possible to provide a film forming method that allows film deposition of uniform thickness, improves target life, and improves step coverage.

[Brief explanation of drawings]

FIG. 1a is a schematic plan view showing one form of the film forming apparatus used in the embodiment of the present invention, FIG. 1b is a cross-sectional view taken along the line BB in FIG. A schematic plan view showing another form of the film forming apparatus used in the example, FIG.
FIG. 3 is a schematic diagram showing a conventional film forming apparatus. 11 ₁ to 11 ₆ , 11 ₁ ′ to 11 ₆ ′...Ion gun, 1
2 ₁ to 12 ₆ ...electromagnet, 13...target, 14...
Supporting member, 15... Wafer, 17... Aluminum alloy film, 18... Erosion area.

Claims (1)

[Claims] 1. Deflecting the first ions emitted from the ion gun by an ion deflecting means and irradiating the target with the first ions,
A method for forming a film of the constituent particles of the target on a substrate, characterized in that, before forming the film, the surface of the substrate is cleaned by irradiating with second ions in advance. 2. The film forming method according to claim 1, wherein the second ion is the same type of ion as the first ion. 3. The film forming method according to claim 1, wherein the substrate is at least a semiconductor substrate. 4. A plurality of the ion guns and the electromagnets are arranged alternately on the same plane to form a ring-shaped body, and the ring-shaped body is arranged between the facing target and the base body and irradiated with the first ions. The film forming method according to claim 1, characterized in that: