JPH02197567A - Plasma sputtering device - Google Patents

Abstract

PURPOSE:To enhance depositing efficiency of sputtered atoms on the step part of the surface of the base plate for a sample by opposing the sputtering faces of targets between a plasma forming chamber and the base plate for the sample and thereby providing the space part and locating the atoms sputtered from the targets to the inside of this space part. CONSTITUTION:The nearly C-shaped cylindrical targets 8 facing inward in sectional view are provided just under a plasma pulling out window 5 in a sample chamber 2. The space part surrounded by the inner circumferential faces of the targets 8 is formed and negative voltage is impressed to the targets 8 by the earthing electrodes 8a. Plasma produced in a plasma forming chamber 1 is introduced into the space part via the pulling out window 5 along the lines M1 of magnetic force of the magnetic field formed by both an exciting coil 6 and the auxiliary exciting coils 6a, 6b. The positive ions in the plasma are accelerated allowed to collide against the surfaces of the targets 8 to sputter them. The atoms flown out by sputtering are ionized in the plasma and introduced to the surface of a base plate S for the sample together with plasma allowed to flow along the lines M1 of magnetic force and film formation is performed. Thereby film formation excellent in coating properties on the step of the surface is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering apparatus using plasma generated by microwaves.

[Conventional technology]

Generally, as a method for forming thin films on sample substrates in the manufacturing process of electronic devices such as semiconductor integrated circuits, chemical vapor deposition (CVD), which uses plasma generated mainly by high-frequency discharge, is used to form silicon-based thin films.
The apor deposition method has been used, and the sputtering method has mainly been used to form thin films of metals or metal compounds.

Among the CVD methods, electron cyclotron resonance (ECR:
Group 1 ectron yclotron Resona
CVD using plasma generated using
This method has been proposed as a method that has the advantage of obtaining dense film quality.

On the other hand, the sputtering method can easily supply metal atoms.

On the other hand, it was difficult to control the film, and there were also problems with the density of the film.

As a method to solve this problem, an ECRC sputtering method combining 1'CR plasma technology and sputtering method has been proposed (Japanese Patent Application Laid-open No. 47728/1983).

FIG. 4 is a schematic vertical cross-sectional view of a conventional ECRC sputtering apparatus, in which numeral 1 indicates a plasma generation chamber.

A microwave inlet 3 sealed with a quartz glass plate 3a is provided at the center of one side wall of the plasma generation chamber, and a plasma drawer window 5 is provided at the center of the other side wall facing the microwave inlet 3. A sample chamber 2 is arranged facing the window 5.

One end of a microwave waveguide 4 whose other end is connected to a high frequency oscillator (not shown) is connected to the microwave inlet 3, and surrounds the plasma generation chamber 1 and one end of the waveguide 4 connected thereto. The excitation coil 6 is arranged as shown in FIG.

Inside the sample chamber 2, there is a sample substrate V facing the plasma extraction window 3.
A sample stage 7 on which is placed is placed, and a sputtering target 8 is disposed in the sample chamber 2, facing the periphery immediately below the opening of the plasma extraction window 5, and is enclosed in a shield case 8a. The target 8 is covered with a shield case 8a on its upper, lower end surfaces, and outer peripheral surface except for its inner peripheral surface, and the negative electrode of a DC power source 9 is connected to this by passing through the shield case 8a. .

In such a conventional apparatus, after the pressure inside the plasma generation chamber 1 and the sample chamber 2 is reduced to a predetermined value, gas is supplied to these through a gas supply system (not shown), and the microwave waveguide 4 is Microwaves are introduced into the plasma generation chamber 1 through the plasma generation chamber 1, and a magnetic field is generated by energizing the excitation coil 6, thereby establishing an electron cyclotron resonance condition within the plasma generation chamber 1 and generating plasma. Plasma is generated by the plasma extraction window 5 due to the divergent magnetic field formed by the excitation coil 6.
is introduced into the sample chamber 2 through the sample chamber 2.

Ions in the plasma pass through the plasma extraction window 5 and enter the sample chamber 2.
When the atoms are introduced into the plasma, they are accelerated by the negative voltage applied to the target 8 and impact the surface of the target 8, causing the atoms of the target 8 to be sputtered and ejected into the plasma flow. , some of them lose electrons in the plasma and are ionized into the sample substrate S.
A film is formed by entering the beam.

When applying a film forming process to a sample using the sputtering apparatus described above, in order to form a thin film of a high quality metal or metal compound more stably, Japanese Patent Laid-Open No. 60-50167 discloses a method in which the shape of the target is made into a cylindrical shape. discloses a sputtering apparatus having a configuration in which the sputtering surface of this target intersects a part of the plasma flow. This increased the target current, making it possible to improve the film formation speed and film formation characteristics. Also, JP-A-61
Japanese Patent No. 114518 discloses a sputtering device that further increases target current by using magnetron discharge in addition to ECR discharge.

[Problem to be solved by the invention]

By the way, in the conventional sputtering apparatus described above, the atoms sputtered from the target 8 are usually electrically neutral and fly straight onto the sample substrate S without being affected by magnetic fields or electric fields.

Therefore, in the step portion on the surface of the sample substrate, no film is formed on the side surface of the step which is in the shadow with respect to the flying direction of the sputtered particles, and the entire surface including the step side wall is uniformly coated with a film, or Surface depressions cannot be filled with sputtered material.

The present invention was made to solve this problem, and its purpose is to efficiently ionize sputtered atoms before they reach the sample substrate and control the energy and movement direction of the sputtered particles. It is an object of the present invention to provide a sputtering apparatus that allows sputtered atoms to adhere to a stepped portion of a surface of a sample substrate with high efficiency.

[Means to solve the problem]

A sputtering apparatus according to the present invention according to claim 1 includes a plasma generation chamber that generates a plasma flow using microwaves;
In a sputtering apparatus having a sample chamber into which a plasma flow is introduced from the plasma generation chamber through a plasma extraction window, a sample substrate in the sample chamber, and a sputtering target, a sputtering target is provided between the plasma generation chamber and the sample substrate. A space is provided in which a part or all of the Svanter surface faces each other, and the plasma flow is guided into the space to sputter the target, thereby confining the sputtered neutral particles. It is characterized by the following.

Moreover, the sputtering apparatus according to the present invention according to claim 2 includes:
The sputtering apparatus according to claim 1, further comprising means for forming a magnetic field within the space for guiding the plasma flow.

Furthermore, the sputtering apparatus according to the present invention according to claim 3 is the sputtering apparatus according to claim 1 or 2, comprising:
A sputtering apparatus according to the present invention according to claim 4 is characterized by having an RF high frequency power source for inducing self-bias by applying radio frequency (RF high frequency) to a sample substrate, The sputtering apparatus is characterized by having an electric scraper for applying RF high frequency waves on the surface of the microwave introduction window on the outside of the plasma generation chamber.

[Effect]

In the apparatus of the present invention according to claim 1, a target is sputtered with a plasma flow guided into the space, and the sputtered atoms are brought into contact with plasma in the space to be ionized, and then the sputtered atoms are ionized as a plasma flow. It is guided to the sample substrate and attached to the surface of the sample substrate. This improves the adhesion efficiency of sputtered atoms to the step portion on the surface of the sample substrate.

Further, in the apparatus of the present invention according to claim 2, a plasma flow is reliably guided within the localized space by a magnetic field, thereby improving ionization efficiency.

In addition, in the apparatus of the present invention according to claim 3, the magnetic field is induced on the surface of the sample substrate by a high frequency source in the RF high frequency region for sputtered particles or ions in plasma that are ionized and have a magnetic field controlled by an electric field. , which controls the kinetic energy and direction of movement of ions by applying a self-bias electric field.
Controls the film thickness and film adhesion characteristics of the produced film.

In addition, in the apparatus of the present invention according to claim 4, in order to prevent the conductive film from adhering to the microwave introduction window and obstructing the introduction of microwaves during sputtering metal film deposition, etc., the RF
The conductive film is removed by bias sputtering.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof.

FIG. 1 is a schematic vertical cross-sectional view of a sputtering apparatus according to the present invention, and a plasma generation chamber indicated by 1 in the figure is configured to function as a microwave cavity resonator.
A microwave inlet 3 sealed with quartz glass 3a is provided at the center of the upper wall, and a plasma extraction window 5 is provided at the center of the lower wall. A sample chamber 2 is arranged facing the plasma extraction window 5, and a plasma generation chamber l is connected to the sample chamber 2.
An excitation coil 6 is disposed to surround one end of the microwave waveguide 4 connected thereto. The other end of the microwave waveguide 4 is connected to a high frequency oscillator (not shown), and microwaves emitted from the high frequency oscillator are introduced into the plasma generation chamber 1.

Further, the excitation coil 6 is connected to a DC power supply (not shown), and is configured to form a magnetic field for generating plasma in the plasma generation chamber 1 and to form a diverging magnetic field toward the sample chamber 2 side.

As for the magnetic field, a magnetic field strength that satisfies the electron cyclotron resonance conditions is advantageous for effective generation of plasma.

A sample stage 7 is disposed in the sample chamber 2 at a position facing the plasma extraction window 5, and a sample substrate S is placed on this stage. Further, an auxiliary excitation coil 6b for adjusting the magnetic field distribution in the vicinity of the sample stand 7 is disposed below the sample stand 7.

In the sample chamber 2, a target 8 formed in a substantially C-shaped cylindrical shape with an inward cross-sectional view is provided directly below the plasma extraction window 5. A space is formed. The target 8 is surrounded and supported by a ground electrode 8a having a similar shape over its upper, lower end surfaces and outer peripheral surface except for its inner peripheral surface, and the negative electrode of a sputtering power source 9 is connected to the target 8. A negative voltage of about -300V to -800V is applied to the target 8 by self-biasing using a DC power source or a high frequency power source, and ions in the plasma are drawn toward the inner peripheral surface of the target 8 to perform sputtering.

In addition, the sample chamber 2 in the part where this target 8 is provided
An auxiliary coil 6a is arranged around the outer periphery of the coil 6a.

In such an apparatus of the present invention, the plasma generation chamber 1. After the sample chamber 2 is evacuated and the pressure is reduced to a predetermined value, a meter gas, for example, is introduced into the plasma generation chamber 1 from a gas supply system (not shown), and microwaves are introduced into the plasma generation chamber 1 through the microwave waveguide 4. At the same time, a magnetic field is formed by the excitation coil 6 to establish an electron cyclotron resonance condition in the plasma generation chamber 1 to generate plasma, and the divergent magnetic field formed by the excitation coil 6 causes the plasma to be drawn out through the plasma extraction window 5. is introduced into the sample chamber 2 through the sample chamber 2.

In FIG. 1, M1 is an excitation coil 6, an auxiliary excitation coil 6a,
6b is the line of magnetic force of the magnetic field. As a result of the plasma being introduced into the space surrounded by the inner peripheral surface of the target 8 at a position past the plasma extraction window 5 along the lines of magnetic force of the magnetic field formed by the excitation coil 6, the Ar+ ions in the meter plasma have a negative voltage. is attracted to the target 8 to which is applied, and collides with the surface of the target 8 in an accelerated state,
Sputter this.

Atoms sputtered and ejected from the target 8 lose electrons in the plasma in or around the space, are ionized, and are guided to the surface of the sample substrate S together with the plasma flowing along the lines of magnetic force, resulting in efficient film formation. It will be done.

In the above embodiment, the auxiliary excitation coil 6a reliably guides the plasma flow toward the inner peripheral surface of the target 8, so that the plasma density around the target 8 is high, the target current density is increased, and the deposition rate is also increased. This increases the size and improves plasma usage efficiency.

Further, by adjusting the magnetic field distribution in the vicinity of the sample stand by using the auxiliary excitation coil 6b disposed below the sample stand 7, the plasma flow can be made uniform, and a uniform film can be formed. Furthermore, the sample stage 7 is made of ceramic or other insulating material,
An electrode 7a is buried inside, and an RF power source 7c is connected to this electrode via a matching box 7b to generate an RF bias on the sample substrate S, thereby making it possible to control the energy and directionality of sputtered atoms.

This improves step coverage, that is, step coverage performance.

FIG. 2 is a schematic vertical cross-sectional view showing another embodiment of the present invention, in which a flat cylindrical spatter whose inner wall is open to the plasma flow is provided between the plasma generation chamber 1 and the sample chamber 2. Room 1
0 is provided, and targets 8, 8 are disposed around the sputtering chamber 1O on the outer periphery of the plasma generation chamber 1 and the sample chamber 2, facing each other on the upper and lower sides thereof, and this part is similar to the above. It becomes the space part of. A negative voltage is applied to the target 8.8 by the sputtering power supply 9, and as described above, ions in the plasma are drawn toward the inner peripheral surface of the target 8.8 to perform sputtering. This target 8
．． A pancake-shaped auxiliary coil 10a is installed on the plasma generation chamber 1 side outside the portion where 8 is provided, and an auxiliary coil 10b of the same type is installed on the sample chamber 2 side.

In such an embodiment, in the sample chamber 2, the auxiliary excitation coil 10b operates the excitation coil 6 and the excitation coil 10.
A magnetic field is formed in the opposite direction to the magnetic field caused by a. As a result, the plasma flow introduced along the magnetic field formed by the excitation coil 6 and the excitation coil 10a is directed to the plasma extraction window 5.
It is bent toward the sputtering chamber 10 at a position after passing through the sputtering chamber 10, and the plasma flow is introduced into a space surrounded by the inner peripheral surfaces of the targets 8, 8 in the sputtering chamber 10. As a result, similar to the embodiment shown in FIG. 1, the sputtered atoms ejected from the target 8 lose electrons in the plasma in or around the sputtering chamber 10 and are ionized, guided to the surface of the sample substrate S, and efficiently A good film is formed.

The other configurations and functions of the apparatus of the present invention shown in FIG. 2 are substantially the same as those of the embodiment shown in FIG.

FIG. 3 is a schematic vertical sectional view of the microwave introduction window of the present invention according to claim 4, and shows an embodiment in which RF high frequency waves are applied to the microwave introduction window. 31 is an RF electrode, 11b is a matching box, and llc is an RF power source.

〔Effect of the invention〕

As described above, in the sputtering apparatus of the invention according to claim 1, there is provided a space between the plasma generation chamber and the sample substrate, which has a portion in which a part or all of the sputtering surfaces of the target face each other. Since the sputtered atoms from the target are localized within the space, the sputtered particles do not fly directly onto the surface of the sample substrate, and the sputtered atoms are efficiently ionized. Adhesion efficiency to surface step portions is improved. Furthermore, since the sputtering apparatus of the invention according to claim 2 is provided with means for forming a magnetic field for guiding the plasma flow into the space, the plasma flow is more reliably guided into the space and neutral sputtered particles are removed. is localized.

This increases the plasma density around the target,
The ionization rate of sputtered atoms and the adhesion efficiency to the stepped portions of the sample substrate surface are improved.

In addition, in the sputtering apparatus of the present invention according to claim 3, ions in the plasma or sputtered particles that have been ionized and are controlled by a magnetic field or an electric field are induced by a high frequency source in the RF high frequency region on the surface of the sample substrate. By applying a self-bias electric field to control the kinetic energy and direction of motion of the ions, it is possible to control the film thickness and film adhesion characteristics of the produced film.

In addition, in the sputtering apparatus of the present invention according to claim 4, it is possible to prevent the conductive film from adhering to the microwave introduction window and hindering the introduction of the microwave 9 in metal film sputtering, etc., and to provide stable performance for a long time. This has the effect that it is possible to carry out controlled operations.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a sputtering apparatus according to the present invention, FIG. 2 is a schematic vertical cross-sectional view showing another embodiment of the present invention, and FIG. FIG. 4 is a schematic longitudinal sectional view of a window and a schematic longitudinal sectional view of a conventional sputtering apparatus. l...Plasma generation chamber 2...Sample chamber 5...
・Plasma drawer window 8...Target patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono Funeral map of husband's funeral

Claims (1)

[Claims] 1. A plasma generation chamber that generates plasma using microwaves, a sample chamber that introduces a plasma flow from the plasma generation chamber through a plasma extraction window, and a sample substrate and a sputtering target in the sample chamber. In the sputtering apparatus, a space is provided between the plasma generation chamber and the sample substrate, and the space has a part such that part or all of the sputtering surfaces of the targets face each other, and the plasma is formed in the space. A sputtering apparatus characterized in that the neutral particles sputtered by sputtering of the target are localized in the space and ionized by guiding the target. 2. The sputtering apparatus according to claim 1, further comprising means for forming a magnetic field in the space for guiding the plasma flow. 3. The sputtering apparatus according to claim 1 or 2, further comprising an RF high-frequency power source for inducing self-bias by applying RF high-frequency waves to the sample substrate. 4. On the outside surface of the plasma generation chamber of the microwave introduction window,
Claims 1 and 2 include electrodes for applying RF high frequency waves.
Or the sputtering apparatus according to claim 3.