JPS6046368A - Sputtering target - Google Patents

Abstract

PURPOSE:To increase a film forming amount per unit time, by forming a sputtering targed into a U-shape having an opening part directed to an object to be coated and arranging magnets to both sides of said target. CONSTITUTION:The target 1 in a sputtering apparatus is formed into a U-shape from side plates 4 and a bottom plate 5 and the opening part 1a thererof is directed to a substrate 3 to which a sputtering film is formed. In addition, a W tilament is attached to one end in the target 1 and anode plate 12 to the opposite side therein while magnets 2 each having a yoke are attached to the outer sides of said target 1. The substrate 3 is used as an anode and the target 1 is used as a cathode to apply voltage of 500-1,000V therebetween while a current is supplied to the filament to apply voltage between said filament and the anode plate 12. Glow discharge is generated between the target 1 and the substrate 3 and the molecule of the target 1 is generated but glow discharge is promoted by the thermoelectron from the filament and a large amount of the target molecules are uniformly collided with the substrate 3 by the restriction of the side plates 4 and the magnetic field due to the magnets 2 to form a vapor deposition film having a uniform thichkness at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sputtering target for use in sputtering.

As is well known, sputtering is a process in which plasma ions generated by glow discharge or arc emission collide with a flat target surface, and this impact causes atoms or molecules flying from the target to be deposited on the surface of the object to be coated. I am doing it. By the way, in the conventional sputtering equipment, it is difficult to improve the uniformity of the plasma generated near the target in the heat of summer and the spatial distribution of the plasma.
On top of this, there is the problem that the sputtering rate (in other words, the amount of coating per unit time is small and productivity is low).

On the other hand, in order to determine the plasma density, a magnetic flux is applied in the space near the radiation surface of the target between the target and the handle in a direction perpendicular to the direction of the heart valve. A device (a so-called magnetron type device) is known. However, with this type of device, it is difficult to provide a uniform magnetic flux distribution within the required spatial region near the target, and if the mako target is a ferromagnetic material, the magnetic flux is absorbed within the target. However, due to problems such as not being able to achieve the desired catch, it is not possible to improve productivity sufficiently.

In addition, a Nishiko device is known that heats a tungsten filament or the like toward a space where plasma is generated near the target, emitting thermoelectrons, and increases the plasma density by using the arc plasma of the Oki flow. Generating a uniform arc plasma over a surface requires advanced technology, and in order to achieve this, the equipment becomes complicated and expensive, resulting in a significant rise in production costs. To.

In view of the above problems, the invention was made with the aim of providing a sputtering target that can reduce production costs and improve sputtering efficiency, and in which component atoms are Some sputtering targets that emit molecules have a radiation surface that is formed into a curved surface with a U-shaped cross section or a concave cross section that opens toward the object to be coated.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIGS. 1 and 2 are diagrams showing an example of a sputtering apparatus using a sputtering target according to the invention. In these figures, numeral 1 is a cuget, 2 is a magnet, and 3 is a substrate.

The target 1 is formed into a U-shaped cross section by arranging two rectangular cargo plates 4, 4 in parallel and oriented directions, and connecting the downtown area in the long side direction with a bottom plate 5. This cuguette 1, which is installed with its U-shaped opening 1a facing the substrate 3, is made of a material having the same components as the coating to be formed by spackling. In this embodiment, pure iron is also used.

The outer part of the target 1 except for the opening 1a is covered with a shield 6. The shield 6 is formed by bending a plate of a conductive material (preferably a conductive and non-magnetic material) such as steel into a U-shaped cross section, and is spaced slightly apart from the outer surface of the target 1. It is placed in a state that
The target 1 is fixed to the shield 6 by using an insulating material 7 at its upper edge. A metal water cooling jacket (not shown) is provided between the outer surface of the target 1 and the inner surface of the shield 6 in close contact with the target 1, and the inside of this jacket serves as a cooling water passage 8 for cooling the target 1. There is.

The magnet 2.2 is also arranged along the outer surface of the side plate 4.4 of the target 1. One of these magnets 2, 2 is installed with its north pole facing the target 1, and the other magnet is installed with its south pole facing the target 1, and is firmly fixed by fixing means that is well illustrated. On the surface of each magnet 2.2 facing the target 1, there are magnet yokes 10, 1, respectively.
0 stands firm. Each yoke 10.10 is formed such that the distance between the target 1 and the yoke 10 is the smallest on the side of the opening 1a of the target 1, so that the magnetic flux due to the magnet 2.2 is directed toward the opening 1a of the target 1. The dense fabric is most effective near 1a.

Mako, in this example, as shown in Figure 1, Kugut 1
A tungsten filament 11 is provided at one end, and a positive electrode plate 12 is provided at the other end. It constitutes an arc plasma generator that supplies

In the above-mentioned sputtering apparatus, the substrate 3 is placed at a positive potential (usually 500 to
1000V) is applied. Now, a positive voltage is applied to the anode plate 12 of the arc plasma generator with respect to the tungsten filament 11, and a force is supplied to the tungsten filament 11 to heat it. There is.

Next, the operation of the above sputtering apparatus and the operation of the target 1 will be explained.

First, the atmosphere is reduced to a predetermined pressure, a voltage is applied between the target 1 and the substrate 3, electricity is applied to the tungsten filament 11 to heat it, and a voltage is applied between the tungsten filament 11 and the anode plate 32. Apply. As a result, plasma due to glow discharge or arc discharge is generated between the target 1 and the subduing force 3, and the ions of atoms or electrons collide with the surface of the target 1 to ionize and strike the metal atoms on the surface of the target 1. put out. A large number of metal ions released from the surface of target 1 are
Although the metal ions have momentum in various directions relative to the surface of the target 1, in the target 1 of the present invention, the scattering direction of metal ions is limited by the opening 1a. That is, the metal ions emitted from the bottom plate 5 of the target 1 with momentum in a direction substantially perpendicular to the plane of the bottom plate 5 jump out toward the substrate 3, and also have momentum in a direction other than perpendicular to the plane of the corner 6. The metal ions released by
, 4, the metal ions fly away from the target 1 with momentum in a direction that allows them to pass through the opening 1a. Furthermore, the direction in which the metal ions ejected from the side portion 4.4 of the target 1 is also restricted by the opening 1a. In other words, with the target as described above, it is necessary to give the substrate 3 the same directionality in the direction in which the atomic ions that are ejected from the target 1 are emitted.

In the above target 1, the plasma generated between it and the substrate 3 is surrounded by the side plate 4.4 and the paper board 5, and therefore the probability of plasma ions colliding with the target 1 is lower than that of the conventional flat plate. Since the target is significantly more cylindrical than a conventional target, the amount of ions emitted is increased compared to conventional targets.

In the sputtering apparatus described above, the arc plasma generator comprising the tungsten filament 11 and the anode plate 12 emits thermionic electrons into the space within the target 1 surrounded by the side plates 4, 4 and the bottom plate 5. It functions to facilitate discharge between the substrate 3 and promote an improvement in plasma density.

However, in the above sputtering device, the magnet 2.2 generates a high density magnetic field in the space near the opening 1a of the target 1 in a direction perpendicular to the direction of electric current generated between the target 1 and the substrate 3. let This magnetic field acts to focus the plasma generated between the target 1 and the substrate 3 in the vicinity of the target 1, suppressing the inflow of electric charge into the substrate 3,
It acts to prevent the temperature of the substrate 3 from rising.

However, according to the above-mentioned uninvented target, its cross section is U-shaped, the pole is concave, and the opening is directed toward the object to be coated, and the plasma is directed to the U-shaped or concave shape. Since the sputtered particles are generated on the inner surface of the target formed in a concave shape, a large number of particles are scattered by the plasma ion bombardment, and the flight direction of the sputtered constant is restricted by the opening. Since directionality is given to the object to be heated, the amount of film produced per unit time can be significantly increased, and a highly productive sputtering apparatus can therefore be realized.

In addition, the uninvented target can increase the plasma density and further improve the film formation rate by changing the flow rate of an arc plasma generator. By doing so, even if the target is a ferromagnetic material, the magnetic flux density applied by the magnet can be concentrated in the space near the opening of the target, and therefore the plasma can be focused by the magnetic flux, improving the efficiency of plasma utilization and It is possible to obtain effects such as being able to improve the effect of preventing charge from flowing into the substrate.

In the above embodiment, the target is formed by combining flat plates to have a concave cross section, but the present invention is not limited to this. It is also possible to make the curved surface of the letter shape into a curved shape.

The present invention will be explained in more detail by briefly giving an experimental example.

[Experimental Example 1, Distribution of Magnetic Flux Density] The target 1 shown in FIGS. 1 and 2 was formed using the materials and dimensions shown below.

・Material: Pure iron ・Thickness: 5mm ・Opening dimension: 30mm ・Height (inner glue): 70mm ・Length: 200mm Attach Naro Shield 6 made of a 2mm thick copper plate to the target 1 above, and steel plates 4 and 4. parallel to the outer surface of the
Permanent magnets 2, 2 provided with yokes 10.10 made of pure iron were arranged. The distance between the upper tip of the yoke 10.10 and the shield 6 is 3 mm.

Mako, above the target 1, 50 mm apart from the opening 1a at the edge of the target 1, parallel to the target 1,
Made of glass, width 30mm, length 20mm
Place the 0mm board 3.

The density of the magnetic flux generated between the inner beams of the target 1 when a magnetic field of 2000 oersted is applied by the permanent magnets 2, 2, and the center of the upper end of the target side plate 4 (in the longitudinal direction in Fig. 3). To measure the leakage magnetic field at the central position).

The measured leakage magnetic field was 180 oersted. Further, the distribution of magnetic flux density at the center between the two plates 4, 4 of the target 1 is shown in FIG.

As can be seen from Fig. 3, according to the uninvented target, it is possible to apply a high density magnetic flux to the space near the opening 1a even if the target material is a ferromagnetic material such as pure iron. .

[Experimental Example 2, Measurement of film formation rate] Target 1, substrate 3, etc. used in Experimental Example 1 were subjected to a pressure of 1×1.
In an argon gas atmosphere of 0-3 to 1 x 10-2 Torr, a Narita voltage of 600 V was applied between the target 1 and the substrate 3 with the substrate 3 in the positive position. In this state, the current of the generated plasma discharge is maintained at 3A, and 20VA of power is supplied to the arc plasma generator (tungsten filament 11 and anode plate 12 in Fig. 1), and there are cases where this is not used. , the distribution of the insect retrieval speed of the pure iron coating with respect to the substrate 3 is added below.

FIG. 4 shows the distribution of film formation speed in the width direction of the target 1, and FIG. 5 shows the distribution of the film formation speed in the longitudinal direction of the target 1. Also, the fourth
In both FIG. 5, the solid line indicates the results obtained when an arc plasma generator is used, and the broken line indicates the results obtained when the arc plasma generator is not used.

As shown in Figure 4, in the uninvented target, the speed at which the film is removed onto the substrate is maximum at the center of the width of the target, and the flight direction of the particles snotted from the target is directed by the opening of the target. I understand that you should be concentrating on those who have been affected. Furthermore, as shown in FIG. 5, it can be seen that in the uninvented target, a substantially uniform film formation rate can be obtained in the length direction.

An embodiment of the present invention will be briefly shown.

Example (Formation of film on resin film) Using the same target as in Experimental Examples 1 and 2, form an iron film on a polyimide film.

As shown in FIG. 6, a semicircular columnar body is arranged parallel to the target 1 as the substrate 3', and the film F to be covered is placed on a supply roll that is stretched in both directions of the substrate 3'. 15, and the winding roll 16 is pulled out through the curved surface of the substrate 3'.
I made it wind up at a constant speed.

The sputtering conditions were the same as in Experimental Example 2, and the Mako film F had a thickness of 0.1 mm, a width of 200 nm, and a length of 5 m. The moving speed of film F is 10
cm/min.

The film F was treated over its entire length under the above conditions to form an iron coating on the surface.A uniform film with a thickness of 2000A was formed in the width direction with a width of 130nm at the center over the entire length of the obtained iron-coated film. After the iron coating was formed, we measured the strength of the iron coating and found that it had an Hc of 60e, indicating that it had excellent magnetic properties.

From the above results, the uninvented target is suitable for large-scale production, as it is capable of producing a homogeneous sputter coating on films, plate-like materials, etc. that have as much heat as the length of the target. I realized that it was something.

Figures 1 and 2 are views showing one embodiment of the target according to the invention, in which Figure 1 is a perspective view, Figure 2 is a front sectional view, and Figure 3 is a front sectional view. Figures 4 and 5 are diagrams showing the measurement results of the magnetic flux density in Experimental Example 1, and Figures 4 and 5 are diagrams showing the measurement results of the film formation rate distribution in Experimental Example 2. FIG. 5 is a diagram showing the velocity distribution in the height direction of the target, and FIG. 6 is a diagram showing the schematic configuration of the sputtering apparatus used in the example.

3... Sputter target, 1a... Opening, 2...
... Magnet, 3... Substrate, 11... Tungsten filament (arc plasma generator), 32... Anode plate (arc plasma generator).

Offender: Showa Denko Co., Ltd. Agent: Patent Attorney Masatake Shiga

Claims (1)

[Claims] 1. In a sputtering target that emits component atoms and molecules for several minutes upon plasma ion bombardment on a radiation surface directed toward the object to be coated, the radiation surface is directed toward the object to be coated. A sputtering target characterized by being formed into a curved surface with an open U-shaped cross section or a concave cross section; 2. A sputtering target comprising a magnet for generating a magnetic field between walls near the radiation surface. The sputtering target according to item 1. 3. The sputtering target according to claim 1 or 2, comprising an arc plasma generator that supplies electrons to a space near the radiation surface.