JPH02254158A - Thin film forming device - Google Patents

Abstract

PURPOSE:To prevent the damage of the film on a substrate by the bombardment of a negative electrifying body by disposing magnets on the rear surface of a negative potential electrode, such as target, of the thin film forming device, such as sputtering device, and providing an acceleration area for preventing the impact of the electrifying body, such as negative ion, generated from the target by the magnetic lines of force thereof. CONSTITUTION:The substrate 41 mounted to a holder 42 is carried into a vacuum treating chamber 11 and a high voltage is impressed by an electric power supplying means 50 to the substrate 41 as a positive electrode and an electrode 20 mounted with the target 21 consisting of a film forming material as a negative electrode to effect a glow discharge in the presence of gas, such as Ar, introduced from an introducing port 72 to bombard the target 21 by the Ar ions, by which the thin film is formed as positive ions on the substrate. The magnets 32, 33 are mounted on the rear surface of the electrode 20 and the acceleration area 36 for preventing the bombardment by the negative ions of the large mass generated from the target 21 is formed by the magnetic lines 35 of force thereof, by which the damage and nonuniformity of the formed film by the bombardment of the negative electrifying body are prevented and the excellent film is formed on the surface of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a thin film device that utilizes discharge, and is particularly effective when applied to cases where it is desired to avoid the adverse effects of negatively charged bodies generated on the discharge surface.

(Prior art) Equipment that uses electrical discharge includes sputtering equipment, CVD equipment, etching equipment, surface modification equipment, etc. (hereinafter referred to simply as thin film equipment)
There is. These techniques have achieved excellent results by skillfully utilizing plasma generated by electrical discharge. In particular, devices that combine this with a magnetic field have succeeded in obtaining high-density plasma and speeding up processing. Some examples of these are also described in "Fundamentals of Thin Film Creation" by Tatsuo Asamaki in the Nikkan Kogyo Shimbun series.

(Problems to be Solved by the Invention 2) These devices have electrode surfaces at a negative potential, especially devices whose electrode surfaces are made of oxides or alloys, which have a large mass and are negatively charged. The body is easy to develop. This is also stated, for example, in the paper below.

1) A. Benninghoven and L.
Weidmann, 5urf.

Sci, 41 (1978) 4832) J, J
Cuomo, R.J., Gambino, J.M.
E., Harperand J., D. Kuptsis,
J, Vac, Sci, Technol.

15 (1978) 28].

To give a few examples, when the thin film to be formed is an oxide, the amount of 0- ions becomes large, especially when oxygen is present in the atmosphere.

Furthermore, when it is desired to obtain a thin film of an alloy of Au and Sm, a large amount of Au- ions are generated.

In conventional devices, these ions are accelerated by the electric field between the electrodes and mainly flow into the positive potential electrode, and in most cases do not have any adverse effect on thin film processing. Some examples are listed below.

In sputtering equipment, these negative ions impact the object to be processed (hereinafter referred to as the substrate) placed opposite to it, destroying the crystals of the thin film, deteriorating the film quality, or in extreme cases, causing damage to the entire surface of the substrate or There are times when the thin film does not adhere to some areas. In the CVD apparatus, it is possible to measure the direction of the film formation rate by using these negative ions, but this causes the same drawbacks as mentioned above.

In an etching device, as in other devices, ions are accelerated in various directions, but eventually impurities flow into the object to be processed due to sputtering that occurs in the inflow region where ions flow. It can become an impurity in the thin film, or it can cause damage in a broader sense by altering the quality of the thin film or element. The same applies to surface modification equipment.

(Object of the Invention) An object of the present invention is to provide a thin film device that solves these drawbacks.

(Means to Solve the Problem) In this invention, an acceleration region ``'' is provided to prevent ion shock generated by an electrode with a negative potential, and the charged body is accelerated in a direction that does not cause problems, thereby causing crystal destruction and destruction. Solve defects such as deterioration of film quality and lack of film adhesion. When it is desired to eliminate the influence of impurities caused by the sputtered material in the inflow region of the charged body, this can be done by providing a means for preventing it, for example, a deceleration electrode that decelerates the ions.

(Function) The charged body generated at the negative potential electrode is brought to a place other than the area where thin film processing is desired by the acceleration area for shock prevention.
Where thin film processing is desired, excellent processing can be performed using only desirable particles.

・4 For example, when forming a film by sputtering, especially when creating a multi-component thin film such as an oxide high-temperature superconductor, negative ions are taken elsewhere, and the sputtered material is brought onto the substrate to produce an excellent material. make a thin film.

In CVD, etching, and surface modification, target neutrals such as radicals are flowed in at L7 to prevent charged objects from flowing onto the object to be processed, which is placed facing a negative potential electrode. process.

(Example) Next, this invention will be explained in detail with reference to the drawings.

The embodiments shown in FIG. 1 (a schematic front cross-sectional view of the device) and FIG.
0, means 30 for setting a magnetic field, means 40 for holding the substrate
, means 50 for supplying electric power, means 60 for exhausting air, and means 70 for introducing gas.

The vacuum container 10 includes a processing chamber 11, a pre-evacuation chamber 12, a valve 13 separating the compartments, and a door 14 of the pre-evacuation chamber. Each room No. 4 is evacuated by exhaust systems 61 and 62 of exhaust means 60. It is desirable that the processing chamber 11 be evacuated to as high a degree of vacuum as possible. The transport mechanism 15 (
Indicated only by arrows. A number of practical examples are given in the aforementioned book, Fundamentals of Thin Film Preparation J.

The electrode 20 is an electrode plate 21 (which serves as a target in sputtering equipment, and materials suitable for each purpose are used in CVD, etching, surface modification, etc., such as SiC, alumina,
(Aβ etc. are used), container 22, shield 23, insulator 24, introduction pipe 25 for introducing date and time, refrigerant introduction pipe 26
, the same discharge pipe 27, and a surface 28 for generating electric discharge.

The means 30 for setting a magnetic field includes magnets 32, 33 and a yoke 3.
4. A pole piece 31 (provided if necessary) generates a group of magnetic lines of force 35 that generates an endless L-channel discharge. During discharge, high-density electrons are wrapped inside this group of magnetic lines of force.

The means 40 for holding the substrate includes a substrate 41, a holder 421 .
It consists of an insulator 43, an electric power or refrigerant introduction pipe 44, and a power source 45 (direct current, alternating current, RF, microwave, etc., and a wide variety of power sources that can provide both positive and negative potentials can be used). Operate while maintaining the required potential.

The means 50 for supplying power includes a power source 51 and a matching box 52 .

The means 70 for introducing gas consists of an /A amount control valve 71 and a gas cylinder 72. Although this embodiment is configured with only one system of introduction means, multiple systems may be used if necessary.

The device operates like a conventional thin film device.

Here, we will particularly describe the case where a B a Y Cu, 0-based superconducting thin film is created by sputtering. Electrode plate 2
1 in diameter 1. OOmm Y+ Baz Cu3.07
A thin film was formed using a −α target under the following sputtering conditions. In addition, a similar conventional sputtering apparatus, No. 9]
A thin film was also created under the same conditions in the example.

Plate power and frequency 150 W 13.56 M
Hz Distance between target substrates 30M Substrate material MgO Substrate temperature 300°C Introduced gas Ar 50% 0 □ 50% Target 1 ~ Composition Y, Baz Cu30α The following drawbacks were discovered in the conventional sputtering apparatus.

(1) A thin film is not attached to a portion 411 on the substrate 4 that corresponds to the ion acceleration direction 371.

(2) The composition of the thin film attached to the portion 410 of the substrate 41 facing the center of the targets 1 to 21 also changed slightly, with C11 increasing and Ba decreasing.

On the other hand, in the device of the present invention, since the acceleration direction 37 is radial and the charged body is accelerated toward the outside of the substrate 41, there is no possibility that a thin film will not be deposited on the substrate 41. It was possible to apply a thin film uniformly over the entire surface of the substrate. There was almost no change in the composition of the thin film, and a good thin film could be created. According to the conventional method, the critical temperature Tc at which the electrical resistance becomes zero was 75°, but with the Svantha film made according to the present invention under the same film forming conditions, it was possible to obtain a critical temperature Tc of 83°K.

The reason why such remarkable good results were obtained is considered to be due to the following reasons.

Cations such as Ar”, O” and 02゛ are targets 21
When the target material is sputtered, negative ions, mainly 0-, are generated. On the other hand, on or near the surface of the target 21, a group of magnetic lines of force 35 exist, inside which a large number of electrons are trapped and form a space charge. (where the magnetic field lines intersect).

Therefore, the space potential gradually increases h along the direction of this mountain.
rise That is, the main electric field of the discharge is formed in the direction opposite to the arrow 37 or 371. ○− generated on the target surface
is accelerated in the direction along arrow 37 or 371.

In the conventional sputtering apparatus, the 0'' accelerated in the direction along the arrow 371 impacts the substrate, so that no thin film is formed on the impacted portion 411 on the substrate 41, but in the present invention, the acceleration direction is 37 are provided so as to run radially so as not to intersect with the substrate 21, so this does not occur, and the thin layer 37 is provided over the entire surface of the substrate 41.
I was able to make a model. In other words, the area surrounded by the magnetic field lines 35 forms an acceleration area to prevent impact by 0'' ions,
The negatively charged body is mainly accelerated in the direction of arrow 37. Where this 0-ion is at the anode potential of the discharge (
For example, when it flows into the inner wall of the vacuum chamber 11, it sputters the substance on the surface and adheres to the surface of the object to be processed, becoming an impurity. If you want to avoid this, you can decelerate the ions by providing a deceleration electrode 161 as shown in FIG. The spatter can be prevented.

In addition, 0- ions are generated over the entire surface of the target. In conventional sputtering equipment, these O- ions impact the entire surface, although weakly, so that the composition changes slightly over the entire surface of the substrate. However, in the present invention, this effect or disadvantage is also attenuated, so that compositional changes are further improved.

This phenomenon also occurs in the absence of a magnetic field. For example, if the target y) is used for a long time, a dent as shown in FIG. 9 211 will appear on its surface. The 〇- group accelerated by the electric field generated in the direction perpendicular to the surface of the recess 211 is focused on the plate 41 as shown by the diagonal line 361 due to a kind of lens effect, and the thin film is also blocked at the concentrated portion. In this case, it is desirable to take measures such as the embodiment shown in FIG. 3, which will be described below.

FIG. 3 shows another embodiment. In this embodiment, the central magnet 32 is tilted, and the acceleration direction 3 described above is
The radiation angle of No. 7 is tilted even more strongly. The surface of this electrode may be a convex surface as shown by the broken line 211, a concave surface as shown at 212, a flat surface, or a surface of other shapes.

This can be done when a magnetic field is used, or when there is no magnetic field, by providing an acceleration region for shock prevention using only an electric field, the negatively charged object can be accelerated in the desired direction. The body may be detached from the substrate and removed.

FIG. 4 shows a cross-sectional view of only the magnet portion of the target portion of an example using another second magnetic device. In this embodiment, 82 is a central magnet, 83 is a surrounding magnet, 84 is a yoke, and 85 is a line of magnetic force. In this embodiment, the radial acceleration direction 37 is realized by the lines of magnetic force 35 and 85 that repel each other.

FIG. 5 shows another example similar to that shown in FIG. 4 (2). In this embodiment, substantially similar to the embodiment of FIG. 4, the second magnetic device consists of a single magnet 82''. In the embodiment of FIGS. An efficient magnetic field can be set.

FIG. 6 and FIG. 7 further show diagrams similar to FIG. 4 of other embodiments, respectively. In these embodiments, the negatively charged body is accelerated in the outer circumferential direction in FIG. 6 and in the centripetal direction in FIG. 7 by magnets that attract each other, thereby preventing impact on the substrate. In the case of FIG. 7, it is suitable to arrange the substrates along the outer periphery or to use a donut-shaped substrate.

FIG. 8 shows yet another embodiment.

In this embodiment, the electrode 20 is rectangular.

A chain line 39 indicates a line of intersection between the arrow 37 in the acceleration direction in each of the figures described above and the surface of the electrode. In this way, the shape of the electrode can be made into any shape. The shape of the electrode surface can also be freely designed.

Although various embodiments have been described, the following does not have a limiting meaning in any way, and many changes are possible, and individual elemental technologies in the embodiments of this specification can be used in other embodiments. can be incorporated or combined. For example, the surface shape of the electrode in FIG. 3 can be superimposed on the electrodes in other figures. Furthermore, it is of course possible to incorporate or combine various conventionally known techniques into the apparatus of the present invention.

Furthermore, although permanent magnets were used to set the magnetic field in ``2'', it is also possible to use electromagnets to achieve the lines of magnetic force shown in the figure, and it can be designed to suit the purpose. It is also possible to add various types of control by processing the magnetic field while roughly changing it. Furthermore, the shape of the magnetic field is not limited to that shown in the drawings, and various shapes are possible.

=-For boat fishing, it is often convenient for the lines of magnetic force to have many parts parallel to the surface of the electrode, since this will impact the electrode uniformly. It can be seen that the embodiments of FIGS. 4 and 5 have more of the above-mentioned parallel parts than the other examples. It is also an important embodiment of the present invention to use the third and fourth magnetic means or to design the magnetic field setting means 30 accordingly.

Further, when it is desired to make the processing distribution a predetermined value (for example, uniform), it is also possible to move the means 30 for setting the magnetic field inside the electrode 20. The method of movement is not limited to simple uniaxial rotation, but may also be an eccentric link, vertical movement, or a combination of these.

(Effects of the Invention) According to the present invention, it is possible to significantly reduce the impact on the object to be processed due to the negatively charged bodies generated in the electrode and the plasma, resulting in excellent film formation, thin film processing, surface modification, etc. It can be carried out.

[Brief explanation of drawings]

Figures 1 and 2, Figure 3, Figure 4, Figure 5, Figure 6,
7 and 8 are diagrams showing an embodiment of the present invention, and FIG. 9 is a diagram showing an embodiment of the invention, respectively.
The figure shows an example of a conventional device. In the figure, 10 is a vacuum container,
20 is an electrode, 27 is a surface for causing discharge, 30 is a means for setting a magnetic field, 36 is an acceleration region for preventing impact, 40
50 is a means for supplying power; 6 is a stage for holding a substrate;
0 is a means for exhausting air, and 70 is a means for introducing gas.

Claims (2)

[Claims] (1) A vacuum container that can create a vacuum inside, an electrode that has a surface for generating a discharge inside the container, an acceleration region near the surface to prevent impact, and a magnetic field that generates a tunnel-shaped discharge. a means for setting a substrate near the electrode, a means for supplying power to the electrode, a means for evacuating the inside of the vacuum container, and a means for introducing gas. . (2) The thin film device according to claim (1), wherein the acceleration region for preventing impact is formed by an electric field.