JPS6365754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sputtering apparatus for producing a thin film in a vacuum, and particularly to a sputtering apparatus that can prevent temperature rise and damage to a substrate.

Conventionally, a sputtering apparatus for producing thin films in large quantities has a total of three sputtering chambers 10 for producing thin films, a substrate tray insertion chamber 20, and a substrate tray removal chamber 30, as shown in the configuration example in FIG. It has a vacuum chamber that can independently evacuate and maintain a vacuum. The three vacuum chambers are connected through gate valves 22 and 32. Normally, the sputtering chamber 10 is kept under vacuum, and there is a substrate tray insertion chamber 20 and a substrate tray take-out chamber 30 for loading and unloading substrate trays. is released to the atmosphere by leak valves 24 and 34, or evacuated to the atmosphere through exhaust ports 23 and 33 by a pump (not shown) in the directions of arrows e and f. The substrate tray 11 loaded with substrates is first stored in the substrate tray insertion chamber 20, and then, with the entrance door 21 and gate valve 22 closed, it is moved from the exhaust port 23 in the direction of arrow e by a pump (not shown). Exhausted. When the pressure in the substrate tray insertion chamber 20 becomes sufficiently low, the gate valve 22 is opened, and the substrate trays 11 are placed on a rail (not shown) and sequentially fed into the sputtering chamber in the direction of arrow a. Here, a thin film is formed on the substrate and sent through the gate valve 32 in the direction of arrow b. The transferred substrates are finally sent to the substrate tray take-out chamber 30 and stored there. After all the substrate trays 11 initially stored in the substrate tray insertion chamber 20 are transferred to the substrate tray unloading chamber 30 via the sputtering chamber 10, the gate valve 32 is closed. Furthermore, the leak valve 34 is opened and exposed to the atmosphere. Then, the door 31 is opened and the substrate tray 11 can be taken out. A gas introduction hole 12 is provided in the sputtering chamber 10 in the direction of arrow c from a cylinder (not shown).
Gas is introduced through the exhaust port 13 and exhausted in the direction of the arrow d by a pump (not shown) through the exhaust port 13. As a result, a discharge state is maintained in the sputtering chamber with the introduced gas flow rate and exhaust gas flow rate balanced, making it suitable for sputtering.
It is maintained at a predetermined constant pressure in the range of 10 ^-3 Torr to 10 ^-2 Torr. Further, if necessary, a substrate heating lamp 17 is provided in the sputtering chamber, and the substrate tray is irradiated with heat rays to raise the temperature of the substrate before forming a thin film. In the sputtering chamber, three sputtering electrodes 14, 14', 14'' are installed along the direction of movement of the substrate tray, with targets 15, 15', 15'' attached to their upper parts, and insulators 16, 16', 14'', respectively. 16''. Each electrode has a sputter power source 41, 41', 41'' and a feed line 4 between the power source and the electrode.
2, 42', 42'' and connection between power supply and ground 4
A sputter power supply system consisting of 3, 43', and 43'' is connected and power is supplied.The substrate tray 11 faces the three targets 15, 15', and 15'' and moves sequentially to reach each target. A thin film is formed on the substrate by the deposition of spatter particles flying from the substrate. The material of each target may be the same or different depending on the purpose. In addition, in the figure, the number of electrodes is three, but
The present invention is effective for two or more, and there is no particular upper limit to the number.

FIG. 2 shows a specific configuration of the sputter electrode 14 in FIG. 1 as a representative of a plurality of sputter electrodes. The electrode 14 is connected to the electrode housing 1
40, a magnet assembly 50 and a target assembly 15 incorporated therein, and an opening 102 provided in the sputter chamber wall surface 101 via an insulator 16.
It is shaped so that the target surface 151 is exposed to the vacuum side from the inside, and is attached and fixed by a clamp mechanism using a plurality of screws (not shown). The target 15 includes a target plate 151, a target holding jig 152, and a target back plate 153.
It is fixed to the electrode housing 140 by bolts (not shown). A magnet assembly 50 consisting of a center magnet 52, an outer magnet 53, and a yoke 51 is disposed within the concave space 141 in the electrode housing.
is incorporated. Although not shown, cooling water is introduced into the space 141 from the outside of the housing and discharged to contact the target back plate 153, so that the heat generated on the surface of the target 151 during discharge is transferred through the cooling water. It is desirable to release it to the outside as a gas. Airtightness between the housing 140 and the target back plate 153 is maintained by an O-ring 142, and an airtightness between the electrode 14 and the insulator 16 is maintained by the O-ring 143, and an airtightness is maintained between the insulator 16 and the vacuum vessel wall 101 by the O-ring 143. The airtightness of each is maintained by an O-ring 144. On the other hand, a shield 144 is provided around the opening 102 to prevent the surface of the target 15 exposed to the vacuum side other than the target surface 151 that is originally intended for sputtering from being subjected to undesirable ion bombardment and being sputtered. and is fixed to the vacuum side of the vacuum container wall 101 by bolts (not shown).

3a, b, and c are a sectional view, a plan view, and a perspective view, respectively, for explaining the operation of the magnet assembly 50 provided in the housing of FIG. 2. FIG. In these figures, the magnetic pole of the center magnet 52 closer to the target back plate 153 is the N pole, and the magnetic pole of the outer circumferential magnet 53 closer to the target back plate is the S pole.
It is considered to be extreme. Therefore, lines of magnetic force are formed starting from the central magnetic pole and reaching the outer magnetic pole as indicated by the arrow 54. Although the figure can only show a finite number of magnetic lines of force, in reality it is infinite. As a result, in the sputter electrode provided with the magnet assembly, countless lines of magnetic force are arranged in an annular manner on the surface of the target 15 shown in FIG. 2, emanating from the center and entering the outer periphery. In this state, when a high voltage negative with respect to the ground potential is applied to the sputter electrode, the combination of the electric field perpendicular to the target surface and the magnetic field having the shape described above causes the electrons to move along the target surface in an annular shape of magnetic lines of force. Perform a circular drift motion along the arrangement. As a result, low voltage and large current discharge is achieved, making it possible to fabricate sputtered films at high speed. Furthermore, FIG. 4 shows the trajectory of electron drift motion on the target surface. In the figure, the electron is connected to the ring line 55
Perform a drift motion in the direction of the arrow along.

FIG. 5a shows the locus of drift motion of electrons on each target surface when sputtering is performed by simultaneously supplying power to three sputter electrodes in the conventional example of FIG. 1. As can be seen in the figure, as a result of arranging three sputter electrodes in parallel with magnet assemblies of the same configuration, the trajectories α and β of drift electrons in adjacent targets 15 and 15', which are close and parallel to each other, are as follows. The traveling direction of the electrons becomes opposite. Target 1 also adjacent
Trajectories γ and δ of drift electrons 5' and 15'' that are close and parallel are in opposite directions.As a result, electrons in adjacent trajectories repel each other. As a result, the rotating electron groups mutually target other electron groups15,
15', 15'' surfaces toward the substrate tray 11. Therefore, if a thin film is produced in such a state, the temperature of the substrate tray will only increase due to the strong impact of electrons. In addition, the thin film element function is also seriously damaged.The temperature rise and the degree of damage are shown in Figure 1.
This is much larger than would be expected from the case where a thin film was produced by supplying power to only one sputter electrode 14. Moreover, FIG. 5b shows the relative positional relationship of the three magnet assemblies in the electrode arrangement of FIG. 5a and the lines of magnetic force generated thereby. As can be seen from this figure, unlike the case in which there is only one magnet assembly in Figure 3a, when the same magnet assemblies 50, 50', 50'' are arranged in parallel, the lines of magnetic force influence each other and the adjacent The lines of magnetic force generated in the spaces A and A' between the matching magnet assemblies repel each other.As a result, lines of magnetic force 56 and 56' that connect between the target surface and the substrate tray are generated in the spaces A and A' inside the sputtering device. It will be understood that this causes electrons to easily enter the substrate tray side along these lines of magnetic force when discharging, resulting in an adverse effect.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to avoid making the configurations of the magnet assemblies arranged in a plurality of sputter electrodes all the same, and to make the magnet assemblies in adjacent sputter electrodes the same as the center magnet. By reversing the direction of the magnetic poles of the outer circumferential magnet, the energy of electrons incident on the substrate surface from plasma during sputtering is lowered, and temperature rise and damage to the substrate caused by impact of electrons on the substrate surface is prevented. The purpose of the present invention is to provide a sputtering device that can perform sputtering.

According to the present invention, there is provided a vacuum container equipped with a pump for evacuation, a substrate holder in the vacuum container to which a substrate for processing a thin film is attached, and a substrate holder in the vacuum container facing the substrate. a plurality of sputtering electrodes with planar targets disposed for depositing a film on the substrate, and a gas for supplying gas to the vacuum vessel and, on the other hand, maintaining an appropriate pressure within the vacuum vessel while evacuating the vessel. In sputter mounting, which consists of a control system and a sputter power supply system that supplies power to the plurality of sputter electrodes, each of the plurality of sputter electrodes having the planar target has an electron restraining force due to an electromagnetic field on its plane. As a result, a closed annular locus of electron drift motion is formed, and each sputter electrode is arranged so that the directions of electron drift motion on the target surface are parallel to each other in the same direction at the nearest location of the adjacent electrodes. A sputtering device characterized in that the sputtering devices are arranged is obtained.

Next, examples of the sputtering apparatus according to the present invention will be described with reference to the drawings.

In this embodiment, the three sputter electrodes 14, 14' and 1 in the sputter apparatus shown in FIG.
4″, sputter electrodes 14, 1, respectively.
4'a and 14'' are used. Of these, the electrodes 14 and 14'' on both sides incorporate magnet assemblies 50 and 50'' of the same configuration as shown in FIG. 14'a has a built-in magnet assembly 50'a configured as shown in FIG. 6a.The other configurations are the same as in FIG. The explanation will be given with reference to the same symbols as in the figure.Now,
In FIG. 6a showing the configuration of the magnet assembly 50'a,
The magnetic pole of the center magnet 52'a on the yoke 51'a on the side closer to the target substrate is the S pole, and the magnetic pole of the outer peripheral magnet 53'a on the side closer to the target back plate is the N pole. Therefore, compared to the case of the magnet assembly of FIG. 3a, the direction of the magnetic field lines is reversed, starting from the outer magnetic pole and reaching the central magnetic pole. In addition, Fig. 6b shows
Figure 6a shows a plan view of the magnet assembly of Figure 6a; Furthermore, FIG. 7 shows the trajectory of the drift motion of electrons on the target surface when discharging is carried out by incorporating the magnet assembly 50'a shown in FIGS. 6a and 6b into the housing 140a of the sputter electrode 14'a. . In the figure,
Please note that the arrow indicating the direction in which the electrons travel is in the opposite direction to that in FIG. 4.

FIG. 8a shows the three sputter electrodes 14, 1
4'a and 14'', the trajectory of electron drift motion on each target surface is shown when sputtering is performed by simultaneously supplying power to three electrodes.Compared with Fig. 5a, 3 Target 15'a in the center among the targets
Please note that the direction of the arrow indicating the traveling direction of the electrons in the drift locus 55'a above is reversed. As a result, adjacent targets 15 and 1
The drift electron trajectories α and β', which are close to each other and parallel to each other, have the same traveling direction, and are also close to and parallel to the adjacent targets 15'a and 15''. The trajectory γ' and δ of the drift electrons have the same traveling direction. Therefore, the mutual repulsion of the rotating group of electrons that was occurring is suppressed, and sputtering can be performed by applying power to multiple electrodes at the same time. However, damage due to temperature rise and electron bombardment of the substrate can be kept sufficiently low.
FIG. 3 is a diagram showing the relative relationship between individual magnet assemblies and lines of magnetic force generated thereby. Unlike the case in FIG. 5b, the lines of magnetic force occurring in the spaces A and A' between adjacent magnet assemblies do not repel each other, but exit from one pole and enter the other pole. As a result, almost no magnetic lines of force connecting the target surface and the substrate tray are formed in the spaces A and A' within the sputtering apparatus. Therefore, even if three sputter electrodes are arranged side by side, a phenomenon in which a large number of electrons are incident on the substrate tray does not occur.

For example, using a conventional sputtering device having the electrode arrangement shown in FIG. 5b, an argon pressure of 2×10 ^-3 Torr,
Applied voltage of each electrode 400V, total discharge current of each electrode approx.
When sputtering is carried out under the conditions of 2.7A,
The electron current flowing into the tray 11 is equal to the total discharge current.
It turned out to be over 90%. On the other hand, in the sputtering apparatus having the electrode arrangement shown in FIG. 8b, which is an embodiment of the present invention, even under the same conditions, the tray
1, it was confirmed that only 10% or less of the total discharge current flows into the electron current. In the present invention, since the flow of electron current into the tray is suppressed, temperature rise and damage to the substrate are also suppressed accordingly.

The conventional electrode device described above and the electrode device of the present invention will be compared using an actual example. The target was ^copper , the length of the substrate was 150 mm, the width was 50 mm, When using ABS plastic resin with a thickness of 3 mm and soda glass, with conventional sputtering equipment, the center of the ABS plastic resin became convex by 10 mm. Furthermore, the copper film on the soda glass lacked the original luster of copper and turned black. On the other hand, when the sputtering device of the embodiment of the present invention is used, the deformation of the central part of the ABS plastic resin is within 0.5 mm, and considering the initial variation in measurement accuracy, it can be said that there is no deformation. In addition, a copper film on soda glass with metallic luster was obtained.

In addition, in the above embodiment, the case where three sputter electrodes are arranged is shown as an example, but
The number of sputter electrodes is not limited to this. Further, the shape of the sputter electrodes is not limited to a rectangular shape, but may be arranged in a circular shape, for example, as shown in targets 15b, 15'b and 15"b in FIG.

FIG. 10 is a perspective view showing the arrangement of targets for explaining another example of the sputter electrode according to the present invention. In this figure, a cylindrical substrate holder 11 shown by a two-dot chain line into which a substrate is inserted.
1 rotates around its central axis 112. On the surfaces of the three targets 15c, 15'c, 15''c placed outside the substrate holder, electrons have trajectories shown by annular lines 55c, 55'c, 55''c with arrows, respectively. A drifting movement is performed. Further, FIG. 11 is a plan view showing the arrangement of targets for explaining still another example of the sputter electrode according to the present invention. According to this example, six circular targets 15
-1 to 15-6 are arranged around the center point A at equal intervals on the same plane. Six circular lines 55-1 to 55-5 each have an arrow on each target surface.
A drift motion of electrons having a trajectory as shown by 5-6 is performed. Note that the substrates not shown in this figure are mounted on a substrate holder placed parallel to the surface where the target is placed, and the six substrates are rotated around an axis perpendicular to the center point A. The spatter particles are deposited on itself. This forms a thin film on the substrate.

As is clear from the above description, according to the present invention, by reversing the direction of the magnetic poles of the center magnet and the outer peripheral magnet in the magnet assemblies in adjacent sputter electrodes among the plurality of sputter electrodes, It is possible to suppress the electron energy incident on the substrate surface from the plasma, thereby preventing unnecessary temperature rise and damage to the substrate, and is highly effective in improving the yield rate for thin film processing.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an example of the configuration of a conventional sputtering device incorporating a plurality of sputtering electrodes, and FIG. 2 shows a specific configuration of the sputtering electrode 14 in FIG. 1 as a representative of the plurality of sputtering electrodes. 3A, 3B, and 3C are a sectional view, a top view, and a perspective view, respectively, for explaining the operation of the magnet assembly 50 provided in the housing of FIG. 2, and FIG. Figure 5a shows the trajectory of drift motion of electrons on the target surface shown in Figure 5. Figure 5a shows the trajectory of each target surface when sputtering is performed by simultaneously supplying power to three sputter electrodes in the conventional example of Figure 1. Figure 5b is a diagram showing the locus of the drift motion of electrons in Figure 5a, and Figure 5b is a diagram showing the relative positional relationship of the three magnet assemblies in the electrode arrangement of Figure 5a and the lines of magnetic force generated thereby. Figures a and b illustrate the first embodiment of the invention.
A cross-sectional view and a plan view, respectively, showing the structure of a magnet assembly applied in place of the central sputter electrode of the three in the figure, FIG.
Figure 8a shows the trajectory of drift motion on the target surface when discharging is carried out by incorporating a magnet assembly into the housing of the sputter electrode 14'a. Figure 8b shows the locus of the drift movement of electrons on the target surface when power is supplied to three electrodes at the same time with the arrangement of the three magnets in the electrode arrangement of Figure 8a. FIG. 9 shows the drift motion of electrons on the corresponding target surface when the three sputter electrodes in the embodiment of the present invention are circular in shape. FIG. 10 is a perspective view showing the shape and arrangement of targets to explain another example of the sputter electrode according to the present invention, and FIG. 11 illustrates still another example of the sputter electrode according to the present invention. 1 is a plan view showing the shape and arrangement of targets for sputtering. In the figure, 10 is a sputtering chamber, 11 is a substrate tray, 14, 14', 14'a, 14'' are sputtering electrodes, and 15, 15', 15' a, 15'' is the target, 50, 50', 50'a, 50'' is the magnet assembly,
51 and 51'a are yokes, 52 and 52'a are center magnets, 53 and 53'a are outer peripheral magnets, and 140 is a housing.

Claims (1)

[Claims] 1. A vacuum container equipped with a pump for evacuation, a substrate holder in the vacuum container to which a substrate for processing a thin film is attached, and a substrate holder placed on the substrate opposite to the substrate in the vacuum container. a plurality of sputtering electrodes having planar targets arranged for coating, and supplying gas to the vacuum vessel;
On the other hand, in a sputtering apparatus comprising a gas control system for appropriately maintaining the pressure inside the vacuum vessel while evacuating the vessel, and a sputter power supply system for supplying power to the plurality of sputter electrodes, a plurality of sputters each having the planar target are provided. On each electrode, a closed ring-shaped locus of drift motion of electrons is formed by the electron restraining force caused by the electromagnetic field on each electrode.
A sputtering device characterized in that each of the sputtering electrodes is arranged so that the directions of drift motion of electrons on the target surface are the same and parallel to each other at the nearest location of the adjacent electrodes.