JPS59229480A - Sputtering device - Google Patents

Abstract

PURPOSE:To provide a titled device which can form a film having particularly high deposition density and good quality with good uniformity by forming an electrode to be used as a cathode electrode or high frequency electrode into plural plane plates having a certain angle relative with each other and installing a flat plate-shaped target on these plural electrodes in tight contact therewith. CONSTITUTION:The above-mentioned electrode 41 is constituted of plural plane plates having a certain angle of inclination relative with each other and a flat plate-shaped target 42 is installed in tight contact with each electrode plate surface. The periphery of the electrode 41 and the target 42 is covered with an electrode shield 43. In the figure, 44 denotes a vacuum vessel, 45 a base plate support, 46 a base plate and 47 a shutter, respectively. When electric disharge is started from the electrode 41, target constituting atoms are driven off from the surface of the target 42 and the film of the atoms is formed on the base plate 46 attached on the support 45. The respective surfaces of the target 42 incline approximately at the same angle of inclination respectively to the surface of the plate 46. The target constituting atoms are therefore made incident at approximately the same quantity from the regions A and B of the target 45 to the entire surface of the plate 46, by which the thickness of the film on the plate 46 is made uniform and further the characteristic is made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a sputtering apparatus that knocks out target constituent atoms from a target surface by collision with high-energy ions and deposits these atoms on a substrate to form a thin film;
In particular, it relates to a sputtering apparatus equipped with electrodes and a target structure that can form a high-quality film with good uniformity at a high deposition rate, and can be applied, for example, to the manufacture of semiconductor devices.

[Background of the invention]

In recent years, the use of sputtering methods has rapidly increased in the production of semiconductor devices, which are undergoing rapid development. A conventional sputtering apparatus of this type has a configuration shown in FIG. In the vacuum chamber 11, a flat plate-shaped electrode 12 serving as a cathode or a high-frequency electrode and a target 13 are installed on the electrode 12'', and an electrode shield 14 is provided around the electrode 12 and the target 13. A substrate support stand 15 is placed in front of the substrate support 13 with a shutter 17 in between. After setting the substrate 16 on the substrate support stand 15, the vacuum chamber 11 is evacuated, and an inert gas such as Ar, 02 or N2 is evacuated.
When a predetermined amount of an active gas such as the like is introduced and a negative voltage or a high frequency voltage is applied to the electrode 12, a glow discharge occurs and high-energy ions are generated, which collide with the surface of the target 13 and the target constituent atoms are ejected. It will be done.

After continuing this state for a while, if the shutter 17 is removed,
A thin film containing target constituent atoms as a main component is formed on the substrate 16. In order to etch only the target 13 and prevent etching of the electrode 12, in a normal sputtering apparatus, the periphery of the electrode 12 is covered with an electrode shield 4.

It has become clear that conventional sputtering equipment, in which a flat target is placed on a flat electrode, has a number of problems when manufacturing rapidly evolving semiconductor devices.Problems The main reason why dots occur is that semiconductor substrates are becoming larger in diameter.
This will be explained using figures. Atoms ejected from the target 22 placed on the electrode 21'2 are deposited on the substrate 24 on the substrate support stand 23'2. In this case, approximately the same amount of target constituent atoms are incident on the area (a+b) in the center of the substrate 24 from the A area on the left side and the B area on the right side of the target 22, and the angle of incidence on the substrate surface is also , the distribution is symmetrical with respect to the normal. On the other hand, in region a or region b at the periphery of the substrate 24, many target constituent atoms from region A or region B of the target 22 are incident, respectively, and the incident angle distribution to the substrate surface is also different from the normal. It becomes asymmetrical. For these reasons, the thickness of the film formed on the substrate 24 is not uniform, and furthermore, the properties of the film are also non-uniform. Figure 3 shows the thickness distribution when a SiO2 film is formed using a conventional device, and the horizontal axis is the distance from the center of the substrate (c
m), and the vertical axis indicates the standardized film thickness. This third
From the figure, it can be seen that the deposit is thicker in the center of the substrate and becomes thinner towards the periphery. 3. Furthermore, in the sputtering method, targets with different properties are placed on the same electrode. Therefore, it is also extremely effective when forming a thin film consisting of the composition of each target. In this case, as shown in FIG. 2, targeters 22A and 22B having different properties are placed on the electrode 21, so that a thin film having the composition of the targets 22A and 22B is formed on the substrate 24.

However, in that case, the 22
The compositions of A and 22B are the same, and one composition becomes insufficient in the peripheral area.

As described above, conventional sputtering apparatuses have problems with the uniformity of film thickness, film characteristics, and film composition. To solve this problem, the caliber of the target can be increased,
Alternatively, measures have been taken to impart complex movements such as rotation and revolution to the substrate.

However, the former method of increasing the diameter of the target has the problem that it is difficult to increase the diameter of a high-quality target and becomes extremely expensive as the diameter increases, while the latter method gives motion to the substrate. In this method, the vacuum chamber must be made thicker, which creates new problems such as difficulty in maintaining the inside of the chamber at a high vacuum and a slowing of the film formation rate.

As mentioned above, with conventional sputtering equipment, it is difficult to form a high-quality film with good uniformity at a high deposition rate. However, it is necessary to increase the time required to evacuate the vacuum chamber to a high vacuum, and there is a problem in that the cost required for forming the thin film becomes high.

[Object of the Invention] An object of the present invention is to provide a sputtering apparatus having a configuration that can solve the above-mentioned problems of conventional apparatuses.

[Summary of the invention]

A feature of the present invention is that the electrode serving as the cathode electrode or the high-frequency electrode is formed of a plurality of flat plates that are inclined at a certain angle to each other, and a flat target is placed closely on the plurality of electrode plates. be.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.8 Figure 4 is a sectional view showing an embodiment of the present invention, in which a plurality of cathode electrodes or high frequency electrodes (hereinafter referred to as electrodes) 41 are arranged at a certain angle of inclination to each other. These multi-electrode plates are made up of flat plates.
A flat target 42 is installed along each electrode plate surface so as to be in close contact with each other while forming an inclination angle, and the peripheral portions of these electrodes and the target are covered with an electrode shield 43.

The other reference numerals are parts having the same structure as the conventional one, and 44 is a vacuum chamber, 45 is a substrate support stand, 46 is a substrate, and 47 is a shutter. FIG. 5 shows the relative positional relationship between the target and the substrate. In FIG. 5, when a target 52 is placed on an electrode 51 and discharge is started, atoms constituting the target are knocked out from the surface of the target 52.
A film of the atoms is formed on the substrate 54 attached to the substrate support 53. The electrode 51 is composed of a plurality of flat plates that are inclined at a certain angle to each other, and each of these electrode plates is arranged so that the angle of inclination is approximately the same as that of the surface of the substrate 54, so that the electrode 51 is closely attached to the electrode 51. target 5
2 also has a polyhedral shape corresponding to the number of electrodes, and each surface thereof is inclined at approximately the same angle with respect to the surface of the substrate 54. Therefore, substantially the same amount of target constituent atoms are incident from the illustrated regions A and B of the target 52 over the entire surface of the substrate 54, and the incident angle onto the substrate surface is also distributed symmetrically with respect to the normal line. For this reason, the first
Compared to the conventional apparatus shown in FIG. 2 and FIG. 2, the thickness of the film on the substrate is uniform, and the characteristics of the film are also uniform. 6th
The figure shows the thickness distribution of the membrane when the electrode consists of two flat plates. In this case, the angle of inclination between the two planar plates is 20 degrees. The thickness of the film is significantly more uniform than the distribution obtained by the conventional device shown in FIG.

In the above embodiment, the same target is attached on the electrode 51, but the present invention further provides a method for attaching the same target on the electrode 51.

It is also extremely effective when a plurality of targets of different quality are installed and a thin film made of the compositions of those targets is obtained. That is, in FIG. 5, the target installed in area A and the target installed in area B are targets with different compositions. A thin film containing both the composition of the region and the composition of the region is obtained. In this case, since the target in area A and the target in area B face the substrate 54 at approximately the same angle of inclination, the compositions of A and B are the same over the entire surface of the substrate 54, and a film with a uniform composition is formed. can get.

As shown in Fig. 4, remarkable uniformity in film thickness, film properties, and film composition is achieved according to the embodiment shown in Fig. 4, and as a result, it is no longer possible to apply complex movements to the substrate, which were required in the conventional method. There is no need to apply it, and there is an advantage that the film formation rate can be increased. Furthermore, according to this embodiment, a high-quality film can be uniformly formed using a small target, so there is an advantage that the cost required for target formation can be reduced.

In sputtering apparatuses, a magnetic field is generally applied from the outside in order to focus the plasma and improve the film formation rate. Depending on the method of applying a magnetic field, sputtering apparatuses are classified into diode type and magnetron type. The former method applies a magnetic field approximately perpendicular to the surface of the target, while the latter method applies a magnetic field parallel to the surface of the target. In the present invention, when a diode system is employed, a magnetic field can be applied all at once using an electromagnet using a permanent magnet or a Helmholtz coil.

On the other hand, when the magnetron system is employed, as shown in an embodiment in FIG. 7, a group of permanent magnets is built into the electrode so that a plurality of pairs of permanent magnets 72 are arranged on the back surface of the target 71. If sputtering is performed in this state,
A parallel magnetic field is applied to the target surface, and the target surface 73 in this field region is significantly etched, increasing the rate of film formation.

Furthermore, in the present invention, it is also effective to provide a plurality of shutters. FIG. 8 shows a case where two shutters 84 and 85 are arranged so that they have approximately the same inclination angle with respect to the substrate 87. In FIG. 8, after placing targets 82 and 83 with different properties on the electrode 81,
A film is formed on the substrate 87 on the substrate support 86 by opening and closing the shutters 84 and 85. At this time, by temporally controlling the opening and closing of the shutters 84 and 85, the target 82.
A film having a composition of 83 can be formed, and the composition can be easily controlled. Furthermore, as shown in FIG.
Since the surfaces 2.83 are also inclined at approximately the same angle with respect to the surface of the substrate 87, the composition of the formed film can be made uniform over the entire surface of the substrate 87.

The optimal inclination angle between the plurality of planar plates constituting the electrode of the present invention is 10 degrees to 90 degrees (that is, the inclination angle of each planar plate to the substrate is 5 degrees to 45 degrees). 10
If it is less than 100%, the effect of the present invention will not be achieved. On the other hand, 9
When the temperature exceeds 0 degrees, problems such as a decrease in the film formation rate arise. Furthermore, the number, size, and shape of the flat plates in the electrode of the present invention can be arbitrarily selected depending on the purpose.

In addition, in the above-mentioned practical examples, the explanation has been made assuming that the substrate is fixed, but the present invention can also be applied to the case where a thin film is formed by moving the substrate as in the conventional apparatus, and a great effect can be produced. can be done.

〔Effect of the invention〕

As explained above, according to the present invention, there is an advantage that a high-quality thin film can be formed with a uniform thickness at high speed, and that the manufacturing cost can be reduced.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional apparatus, Fig. 2 is an explanatory diagram of a film forming mechanism in the conventional apparatus, Fig. 3 is a distribution diagram of the thickness of a film formed by the conventional apparatus, and Fig. 4 is an embodiment of the present invention. A sectional view of the example, FIG. 5 is an explanatory diagram of the film forming mechanism in FIG. 4, and FIG. 6 is a distribution diagram of the thickness of the film formed by the apparatus of the embodiment of the present invention.
FIG. 7 is a sectional view showing another embodiment of the present invention, and FIG. 8 is a diagram showing an embodiment of the present invention in which a plurality of shutters are provided. Explanation of symbols 11.44...Vacuum chamber 12, 2], 41, 51, 74.81...Electrode 13, 22.42.52.71.82...Target 14.43...Electrode shield 15, 23.45.53.86...Substrate support stand 16.
24, 46, 54, 87...substrate 17, 4.
7.84, 85...Shutter 72...Permanent magnet 73...Target surface Patent applicant Nippon Telegraph and Telephone Public Corporation patent attorney Junnosuke Nakamura 38 Spear 5 Figure 53? 1 in figure 6 (1J'l31y) distance*# (c shoulder) spear figure 7 7゜zusii "'

Claims (3)

[Claims] (1) A substrate placed on a substrate support stand and a target placed on a cathode electrode or high-frequency electrode are placed in a vacuum chamber, facing each other via a shutter, and collision of high-energy ions generated by applying voltage to the electrodes occurs. In a sputtering device that forms a thin film by ejecting atoms constituting the target from the target surface and depositing these atoms on a substrate, the electrodes are formed from a plurality of flat plates that are inclined at a certain angle to each other, and the electrodes are formed on these multiple electrode plates. A sputtering device characterized by flat targets placed in close contact with each other. (2) The sputtering apparatus according to claim 1, wherein each of the planar plate electrodes is a planar plate electrode that includes a plurality of permanent magnets or electromagnets that supply a magnetic field to the target. (3) The sputtering apparatus according to claim 1, wherein the shutter is composed of a plurality of shutter plates, each of which is inclined at the same angle with respect to the substrate.