JPH03138363A - Plasma beam sputtering device - Google Patents

Abstract

PURPOSE:To easily constitute the ion beam sputtering device adapted to a film forming method by using plasma flow for the sputtering of a target and allowing this plasma flow to be arbitrarily bent by the effect of magnetic fields. CONSTITUTION:Gases for plasma discharge and microwaves are respectively introduced into plasma forming chambers 21-1, 21-2 having magnet coils 25-1, 25-2 for forming ECR plasma around the chambers to form the plasma flows 28, 29. The progressing directions of the plasma flows 28, 29 are deflected by magnetic circuits 30, 31 to sputter the target 35 and to form the thin film on a substrate 33. The polarity of the coil 25-1 is set in the direction coinciding with the direction of the magnetic lines of force of the coil 30 and the coil 31 and the coil 25-2 are so set as to have the polarity in the direction opposite therefrom. The magnetic lines of force are then eventually directed from the plasma forming chamber 21-1 toward the target 35 and from the plasma forming chamber 21-2 toward the substrate 33. The degree of freedom in disposition of the target 33, the substrate 33 and the plasma forming source 20-1 is in creased in this way.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an apparatus for forming thin films of various materials on a sample substrate, and in particular, an apparatus for forming thin films of various materials using sputtering using high-density plasma. The present invention relates to a new plasma beam sputtering apparatus for forming at high speed and high efficiency.

[Conventional technology] Film formation and etching using plasma (ions) with highly reactive active particles whose kinetic energy can be controlled as a new process technology for creating next-generation materials and modifying the surface properties of materials. Plasma application technology is attracting attention as a technology. For example, for the development of future functional devices, multi-element film formation technology and film formation technology with excellent film properties are important, and as one of the sources of elements necessary for multi-element film formation. , a thin film forming method using a plasma generation source, and a plasma (ion) assisted NBa forming method in which plasma is irradiated at the same time as forming a thin film on a substrate are attracting attention. In other words, plasma is a source of (1) elements and (2)
) It is a useful means to assist in controlling the physical properties of membranes.

An example of the configuration of a conventional ion beam sputtering apparatus of this type is shown in FIG. In FIG. 6, 1 is an ion source for sputtering, 2 is a gas inlet to the ion source 1, 3 is an ion extraction electrode, and 4 is an ion beam extracted from the electrode 3. 5 is a sputtering target placed in the vacuum sample chamber 12, 6 is a cooling water passage to the target 5, 7 is a substrate holder placed in the vacuum sample chamber 12, and 8 is a substrate placed on the holder 7. Reference numeral 9 represents an assisting ion source, lO represents a gas inlet to the ion source 9, and 11 represents an ion beam from the ion source 9. 13 is a vacuum evacuation system for the vacuum sample chamber 12, and 14 is a gate valve for opening and closing the evacuation system 13.

An inert Ar gas or the like is introduced as a sputtering gas through a gas inlet 2 into an ion source 1 for sputtering to form a plasma. The ions in the plasma are extracted by the electrode 3.
Extracted as an ion beam 4 accelerated to 5 to 5 kV,
Irradiate target 5. By irradiating the target 5 with the ion beam 4, sputter particles are generated from the target 5, and the sputter particles are deposited on the substrate 8, thereby forming a film. This device has the feature that it can form a film on any compound or alloy by targeting the material you want to form a film on. Furthermore, while forming a film using sputtered particles, the assisting ion source 9
By irradiating the film with ion plasma, it is possible to control the physical properties of the film and synthesize new compounds.

[Problems to be Solved by the Invention] However, in such a configuration, the target 5 and the substrate 8
Because it was necessary to irradiate the ion beam with an ion beam that went straight to
Sputtering ion source 1, assisting ion source 9, substrate 8
Furthermore, there are various restrictions on the location of the target 5, its mounting direction, and its inclination, resulting in less freedom in device design. Therefore, the device configuration has become complicated, and it has been difficult to create a simple device configuration.

For example, if you try to adopt a configuration in which the substrate 8 and the target 5 are arranged horizontally or vertically, with the substrate 8 and the target 5 facing each other in parallel, the irradiation angle of the ion beam must be determined in advance.
The installation location and angle of ion source 1 had to be determined. For this reason, the substrate 8, the target 5. Once the positional relationship with the ion source 1 was set, there was almost no degree of freedom to change the relative positional relationship. Therefore, the substrate 8 and the target 5 are usually not properly arranged horizontally or vertically, but rather are arranged at a certain angle as shown in FIG. In this way, when the substrate 8 is arranged at a certain angle,
There was a problem that it was not easy to replace the board 8.

Furthermore, in the reactive ion beam sputtering apparatus, as shown in FIG. 6, assisting ions are irradiated onto the substrate 8 along with the sputtered particles. It was difficult to configure an apparatus to irradiate the substrate 8 at a fixed angle (for example, vertical irradiation).

As described above, the directions of the incident sputtered particles and ion particles are different, and the fact that the direction of the particles incident on the substrate 8 cannot be made perpendicular is a major constraint in forming a high-quality film suitable for the purpose. .

Furthermore, if a device M is configured in which a plurality of targets and ion sources are installed, the configuration becomes extremely complicated, which is a major constraint on the development and progress of ion beam sputtering devices. That is, there is a demand for a loading configuration that allows flexibility in the installation of targets, substrates, and ion sources. If such an apparatus configuration becomes possible, it is expected that ion beam sputtering technology will advance rapidly.

Therefore, an object of the present invention is to maintain the direction of both the sputtered particles and assisting charged particles perpendicular to the substrate even if the substrate and target that face each other in parallel are placed horizontally or vertically. It is an object of the present invention to provide a plasma beam sputtering apparatus having a new configuration with a large degree of freedom without imposing restrictions on the installation position.

[Means for Solving the Problems J] In order to achieve such objects, the present invention provides a plasma generation source that generates plasma, a vacuum sample chamber hermetically coupled to the plasma generation source, a target part disposed in the vacuum sample chamber and emitting sputtered particles by irradiation with a plasma flow from the plasma generation source; and a substrate holder having a substrate on which a film is generated by the particles from the target part; The apparatus is characterized by comprising a plasma flow control section that changes the direction of the plasma flow so that the plasma flow from the plasma generation source is irradiated onto the target section.

[Function] Conventional ion beam sputtering equipment is configured to irradiate the target with a straight-travelling ion beam to obtain sputtered particles, and at the same time irradiate the substrate with a straight-travelling assist ion beam. There were major constraints on the geometry between the sources. Moreover, it was difficult to configure an apparatus for irradiating sputtered particles and assisting ions with directionality perpendicular to the substrate. In particular, an apparatus configuration in which the substrate and target are arranged horizontally or vertically facing each other in parallel has not been realized.

In contrast, in the present invention, plasma is used instead of ions, and the plasma can be bent in any direction by the action of a 6n field, so that the plasma flow has a large angle (for example, perpendicular) to the substrate or target. It has also been made possible to irradiate substrates and targets. Therefore, it is possible to easily configure an apparatus in which a substrate and a target that face each other in parallel are installed horizontally or vertically. Moreover, the directions of the sputtered particles and the assisting charged particles can be aligned and irradiated perpendicularly to the substrate. Furthermore, since two or more plasma streams can be superimposed and the direction of each individual plasma stream can be controlled, a highly flexible device configuration is possible. In particular, the present invention is effective for a plasma generation source that generates plasma using a magnetic field having lines of magnetic force in the same direction as the plasma flow, such as an ECR plasma generation source.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

[Example 1] Fig. 1 is a diagram showing the configuration of the first example of the present invention, in which 20-1 and 20-2 are ECR plasma generation sources, 21-
1,212 is a plasma generation chamber, 22-1.22-2 is a waveguide coupled to the plasma generation chamber 20-1.20-2,
23-1.23-2 is the microwave inlet, 24-1
．． 24-2 is a plasma discharge gas inlet connected to the plasma generation chamber 21-1.21-2, 25-1.25
-2 is a magnet coil for ECR plasma generation arranged around the plasma generation chamber 21-1.21-2, 26
-1.26-2 is a plasma limiter installed in the plasma generation chamber 21-1.21-2, and 27-1.27-2 is an ECR plasma generation source for controlling the ion energy in the plasma at low voltage. It is an insulator for applying voltage to 20-1 and 20-2. 28.29 is
Plasma flow from the plasma generation source 20-1, 20-2, 30.31 is a magnetic circuit for plasma flow control that changes the direction of the plasma flow, and the plasma generation chamber 20
Substrate holder 32. in vacuum sample chamber 39 so as to deflect the traveling direction of plasma flow 28.29 emitted from -1.20-2. It is assumed that the target holder 34 is disposed around the target holder 34. 32 is a substrate holder placed in the vacuum sample chamber 39;
33 is a substrate placed in the holder 32; 34 is a target holder placed on the opposite side of the substrate holder 32 with respect to the axis connecting the plasma generation sources 20-1 and 20-2 in the vacuum sample chamber 39; 35; is a sputtering target placed on the holder 34, and 36 is an ion acceleration bias voltage applied to the holder 32. 37 is a sputtered particle, and 38 is a heater installed in the substrate holder 32. Plasma generation sources 20-1, 20-2 and vacuum sample chamber 39
and are connected airtightly.

In this configuration, an example using an ECR plasma generation source was shown. ECR plasma generates plasma through the interaction of microwaves and a magnetic field, and the ECR condition is 875 Gauss for a 2.45 GHz microwave. Magnetic field distribution is important in order to generate uniform and high-density plasma, and in consideration of the propagation of microwaves in the plasma, the magnetic coils 25-1 and 25-2 each generate a magnetic field of 875 Gauss or more. can occur. Since the direction of the magnetic lines of force of this magnetic field is perpendicular to the electric field of the microwave, it is the direction in which the illustrated plasma flows 28 and 29 flow.

In this way, ECR plasma generation source 20-1.20-2
uses a relatively high magnetic field and the direction of the magnetic field lines matches the direction in which the plasma flow 28.29 is emitted, so by placing another magnetic circuit 30.31 near this This plasma can be easily bent. That is, as shown in FIG. 1, the magnet coils 30 are arranged in a direction that is substantially orthogonal to each other, and the direction of the lines of magnetic force is the same as the direction of the lines of magnetic force of the magnet coil 25-1 used in the ECR plasma generation source 20-1. By doing so, the plasma flow 28 is bent in the direction of the target 35, as shown in the figure, and the target 35 can be irradiated with plasma perpendicularly. On the other hand, magnet coil 3
If the direction of the magnetic field lines at 0 is reversed, they will be bent in the opposite direction.

Therefore, the magnetic coil 25- of the ECR plasma source 20-1 is aligned in the direction that matches the direction of the magnetic field lines of the magnet coil 30.
1, and the magnetic coil 31 of the substrate part and the magnetic coil 25-2 of the plasma generation source 20-2 are set so that the polarity is in the opposite direction, the lines of magnetic force are set in the plasma generation chamber 21-1. The plasma is directed from the plasma generation chamber 21-2 toward the target 35 and from the plasma generation chamber 21-2 toward the substrate 33.

As the electrons move along the magnetic field lines, the ions are also pulled in that direction, and the plasma flow is apparently bent along the upper magnetic field lines. That is, as shown in FIG. 1, the plasma stream 28 comes to irradiate the target 35,
The plasma stream 29 now irradiates the substrate 33 .

Of course, it is also possible to change the direction of the plasma flow 28, 29 toward the substrate 33 or the target 35 by changing the direction and polarity of the current in the magnetic coil of the plasma generation source 20-1, 20-2. For example, as shown in FIG. 2, it is possible to irradiate the target 35 with plasma flows from both plasma generation sources 20-1 and 20-2 to improve the ion current on the target 35 and the uniformity of ion irradiation. It is possible.

In the explanation of FIG. 1, the magnetic circuit 30.3 for plasma control
1 shows an example using a magnetic coil, but E
Magnet coil 25 used in CR plasma generation source
-1.25-2 magnetic lines of force should be directed toward the target or substrate, and it is of course possible to use permanent magnets, and in some cases, the purpose can be achieved by placing soft iron or the like near the substrate.

In addition, in the example of FIG. 1, the plasma generation source 20-1°20
Although an example in which the angle between -2 and the substrate 33 is nearly perpendicular is shown, the present invention is not limited to this angle. For example, if this angle is small, the plasma flow will be more easily bent. Although the case where the magnetic circuits 30 and 31 are fixed is shown, the target 35. By moving the magnet coils 30, 31 near the substrate 33 in the in-plane direction, the plasma flow reaching the target 35 and the substrate 33 can be made spatially uniform.

By applying a negative bias voltage 36 of several hundred ν to several kV to this target portion 35, the plasma flow 28
The ions therein are accelerated and collide with the target 35, whereby constituent elements are sputtered from the target 35 toward the substrate 33. Thereby, a desired film is deposited on the substrate 33.

To give an example of film formation, the sputter target is composed of a desired compound, alloy, etc.
7, ZnO, ^II, Ga, Zn, Si, Ti, In
, Mo, etc. from the plasma generation source, 0□, N2.
By supplying plasma such as ASH4, PH5゜B2Ha, Kr,
Various types of films can be formed, including compound semiconductors such as GaAs and GaAρ^S, and film quality controlled by plasma irradiation with inert gas.

According to such a configuration, the directions of the sputtered particles 37 from the target 35 and the plasma flow 29 from the plasma generation source 20-2 can be made to match, so that the plasma generation source 20-1, 20-2 can be aligned with the substrate. 33, and can be installed at any angle including vertically. As a result, in combination with various supply sources, it becomes possible to form a film with high quality and high quality. In particular, by using vertical incidence, the particles are directed perpendicularly to the substrate 33, so that a homogeneous film can be formed within the plane of the substrate, and it is also possible to form a film in recesses such as grooves.

Films using plasma can form high-quality films at low temperatures due to the bombardment of ions in the plasma, and it is presumed that the effect is greatest in the vertical direction. In general, a configuration in which particles are incident perpendicularly provides a good uniformity of the film, and the density of particles supplied is higher than in the case where the particles are incident at an angle, so that the growth rate can be increased. Furthermore, when the plasma is perpendicular to the substrate, the plasma sheath can be made uniform over the entire substrate, so high frequency bias and DC bias can be stably applied. In this way, the physical properties of the film can be controlled more precisely.

Furthermore, by tilting the central axis of the magnetic coil 30.31 for plasma flow control near the target 35 or near the substrate 33, the angle of the plasma flow incident on the target or substrate can be changed, thereby changing the amount and distribution of sputtered particles. can be changed. As an example, the plasma flow control circuit 30 is shown in FIG.

Further, although the case where the number of plasma generation sources is two has been described so far, the apparatus can be easily constructed even if three or more plasma generation sources are arranged around the vacuum sample chamber 39. For example, as shown in Figure 3, the outer diameter is 50 cm.
If the outer diameter of the plasma generation sources 20 is 20 cm, about six plasma generation sources 20 can be easily installed around the vacuum sample chamber 39. Here, -1°-2 in each reference numeral shown in the first figure is omitted to indicate the same portion.

By changing the polarity of the magnetic coil 25 of this plasma generation source 20, a plasma flow can be selectively guided onto the substrate 33 or onto the target 35. Therefore, whereas conventionally it was difficult to simultaneously irradiate plasma onto the same target or the same substrate using multiple plasma generation sources, with this configuration, plasma from multiple plasma generation sources can be irradiated simultaneously. can be easily overlapped and irradiated onto a substrate or target. In this way, it becomes very easy to improve plasma density and uniformity and to supply various gas species. It is also effective to dedicate each plasma generation source to each gas used so as to prevent contaminants from entering.

Similarly, one device can perform (1) substrate cleaning, (2) various film formation, (3) etching, (4) plasma assist,
(5) Various treatments such as doping can be performed, and each supply source can be used exclusively for supplying a certain element, so high-quality plasma processing with less contaminants can be performed.

[Example 2] Figure 4 shows another example of the present invention, which uses a plasma generation source that does not have magnetic lines of force in the direction of plasma progression or that generates plasma with a weak magnetic field. This is an example of a configuration when

In FIG. 4, 40.41 is a plasma generation source, 42.
43417' is an auxiliary magnetic circuit for plasma control arranged surrounding the plasma flow 28.29; 44.45 is a magnetic circuit for plasma flow control using a permanent magnet; Attach it to the substrate holder 32.

The configuration and operation of this embodiment are exactly the same as those shown in FIG. 1, and a magnetic field is generated by magnetic circuits 42 and 44 so that lines of magnetic force are generated from the plasma generation source 40 toward the target 35. On the other hand, a magnetic field is generated by the magnetic circuits 43 and 45 so that the lines of magnetic force are directed from the plasma generation source 41 toward the substrate 33.

Therefore, the plasma generated by the plasma generation source 40 is caused by the plasma flow 28 in FIG. 4 due to the action of this magnetic field.
As shown, it is bent in the direction of the target 35.

Similarly, the plasma generated by the plasma generation source 41 is
As shown by the plasma stream 29 in FIG. 4, it is bent toward the substrate 33. That is, the operation is exactly the same as in the case of FIG.

[Embodiment 3] FIG. 5 shows another embodiment of the present invention, which is an example of ion-assisted deposition or ion beam mixing in which film formation is performed while simultaneously irradiating an accelerated ion beam.

Here, the assisting plasma generation source 20-2 in FIG.
An ion source 46 is installed instead. In this example, an ECR ion source configuration is shown as the ion source 46, but other ion sources may be used. In the figure, 47 is an ion extraction electrode system provided in the plasma generation chamber 21 constituting the ion source 46, and an example of three electrodes is shown. 48 is an ion beam extracted from the ion extraction electrode 47.

The plasma flow 28 from the plasma generation source 20 is connected to the magnetic circuit 3
0, it is bent in the direction of the target 35. The target 35 is thereby irradiated with the plasma stream 20. The sputtered particles from this target 35
By simultaneously irradiating the substrate 33 with the energy-controlled ion beam 48 while forming a film thereon, a functional high quality film can be formed.

Ion beam assisted deposition, or dynamic ion beam mixing, involves irradiating ions at the same time as film formation, which improves the density of the film.

By controlling physical properties such as stress and adhesion, and by implanting relatively high ions, we can form an alloy film and eliminate the interface, resulting in a strong film that is extremely integrated with the base material and has excellent properties. This is a method of forming a film. For example, Ti,
While forming a film with sputtered particles from a target such as Al1, Si, B6Si, etc., by irradiating N beam from the ion source side at 1 to 49 kV under the control of the extraction electrode system, TiN, Al1N, SiJ< , 8
N etc. are formed. In particular, this method is effective for embedding metal, insulating films, etc. into recesses such as trenches when manufacturing LSIs and the like.

In addition, as described in Example 2, substrate cleaning, film formation,
By sequentially performing processes such as etching and doping without breaking the vacuum, space and time can be made more efficient.

[Effects of the Invention] As described above, according to the present invention, the plasma flow from the plasma generation source can be bent onto the target and, if necessary, toward the substrate.
This method has the advantage that there is a large degree of freedom in the arrangement of the substrate and the plasma generation source, and that an ion beam sputtering apparatus adapted to the intended film formation method can be easily constructed.

In particular, a reactive ion beam sputtering system can be configured when the target and substrate are arranged horizontally or vertically, facing each other in parallel, which not only allows high-speed formation of a film of good quality, but also makes it easy to replace the substrate. This makes it effective as an automated in-process device.

The apparatus of the present invention can be applied to (1) multi-component film formation, (2) plasma/ion assisted deposition, (3) on-beam mixing, (4) ion-doped film formation, etc. using a plasma generation source. Useful. Alternatively, the present invention is also useful as an apparatus that combines processes such as (1) substrate cleaning, (2) various film formations, (3) etching, and (4) doping.

[Brief explanation of the drawing]

1 to 5 are diagrams showing the configuration of various embodiments of the ion beam sputtering apparatus of the present invention, and FIG. 6 is a diagram showing an example of the configuration of a conventional reactive ion beam sputtering apparatus. 1... Ion source for sputtering, 2.10... Gas inlet, 3... Extraction electrode system, 4.11.48... Ion beam, 5.35... Target, 6. ...Cooling water, 7.32...Substrate holder, 8.33...Substrate, 9...Ion source for assist, 12.39...Vacuum sample chamber, 13...Evacuation system, 14 ...Gate valve, 20...ECR plasma generation source, 21...Plasma generation chamber, 22...Waveguide, 23...Microwave inlet, 24...Gas inlet, 25... - Magnet coil, 26... Plasma limiter, 27... Insulator, 28.29... Plasma flow, 30.31... Magnetic circuit for controlling plasma flow, 34...
- Target holder, 36... Bias voltage, 37... Sputtered particles, 38... Heater for heating the substrate, 40.41... Plasma generation source, 4243... Auxiliary magnetic circuit for plasma flow control, 44.
45... Magnetic circuit for plasma flow control, 46... Ion source for assist, 47... Extraction electrode system.

Claims (1)

[Scope of Claims] 1) A plasma generation source that generates plasma; a vacuum sample chamber that is airtightly coupled to the plasma generation source; a target section that emits sputtered particles by irradiation with a plasma stream; a substrate holder on which a substrate on which a film is generated by the particles from the target section is disposed; and a plasma stream from the plasma generation source that irradiates the target section. A plasma beam sputtering apparatus characterized by comprising a plasma flow control section that changes the direction of the plasma flow as shown in FIG. 2) Plasma beam sputtering according to claim 1, characterized in that a magnetic circuit for controlling the plasma flow from the plasma generation source is arranged in the vicinity of the substrate so as to deflect the plasma flow in the direction of the substrate. Device. 3) The plasma beam sputtering apparatus according to claim 1, further comprising an auxiliary magnetic circuit disposed near the plasma generation source for controlling the plasma flow. 4) Claim characterized in that there are two or more plasma generation sources, and at least one of the plasma flows from the two or more plasma generation sources is deflected to irradiate the substrate. 1. The plasma beam sputtering apparatus according to 1.