JPS5924185B2 - sputtering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sputtering apparatus, and particularly to a magnetron sputtering apparatus that operates stably at low pressure.

Conventional sputtering equipment is an internal cathode type magnetron sputtering equipment called a cylindrical post magnetron, as shown in Figure 1, which can produce a coating with good adhesion and relatively uniformity, and has relatively good operation. do.

Reference numeral 10 indicates two anodes arranged separately.

Reference numeral 20 denotes a cathode, which is a plate-shaped portion 2 disposed inside each of the two anodes 10.

a and two plate-shaped parts 2. A rod-shaped portion 2 is fixed to the center of each of a. Consists of b. Reference numeral 30 denotes lines of magnetic force, and the magnetic field is substantially uniform within a space that has a discharge sustaining effect and is divided by a cylinder formed by extending the inner surfaces of the two cathode plate parts 2OA and the two anodes 10 in the longitudinal direction. , and magnetic field lines 3
0 is the rod-shaped part 2 of the cathode.

It is parallel to the axis of b. Electrons are trapped in orthogonal electromagnetic fields in the space that has a discharge sustaining effect, and the trapped electrons ionize molecules of the working gas in the space, and the generated ions are transferred to the rod-shaped part 2 of the cathode. b to sputter the surface material, and the sputtered material is deposited on an object disposed around the outer periphery of the space having a discharge sustaining effect,
Coating is performed. This magnetron sputtering equipment can be installed to isolate the discharge space and the object to be coated, so there is no wasted heat input to the object to be coated, and coating can be performed while maintaining a low temperature. It has the advantage that it can be applied to coating objects that change or deform at high temperatures, such as steel, but it requires a large amount of energy to flow into the rod-shaped part of the cathode, resulting in low energy efficiency and a lower pressure limit that makes it impossible to discharge. The drawback was that it was limited to high values. The drawbacks of the prior art will be explained in more detail with reference to FIGS. 2 and 3.

FIG. 2 is a diagram showing the discharge characteristics of the device shown in FIG. 1, showing the rod-shaped portion 2 of the cathode. It shows the relationship between the current density J flowing into b and the discharge voltage, that is, the potential difference Va between the anode 10 and the cathode 20. In the figure, the numbers shown in mT units indicate the strength of the magnetic field in mysterilla units, and the letters in Pa units indicate the magnitude of pressure in pascal units. It is known from FIG. 2 that the discharge voltage Va is approximately 1.5 KV, and the rod-shaped portion 2 of the cathode. It can be seen that the energy of the ions incident on b is 1.5 Ke or less. In sputtering, the energy with the best yield is determined depending on the substance to be sputtered and the type of working gas, but in general, the energy of the ions is between 1 and 5Ke.
The yield is maximum when . The fact that the maximum energy of the incident ions is 1.5 KeV means that many ions reach the cathode bar 2 below 1 KeV, which results in a low sputtering yield. b, and it can be seen that the amount of spatter relative to the incident energy is limited to a low level. As a result, not only is the energy efficiency of sputtering low and limited, but also a large amount of energy is required in order to make the same amount of material sputtered. There is a danger that as a result of flowing into b, the temperature thereof will rise. This is the first drawback of conventional magnetron sputtering equipment. FIG. 3 is a diagram showing the relationship between the working gas pressure P and the discharge voltage a, obtained under the condition that the discharge current is constant. The figure shows that by increasing the magnetic field, it is possible to discharge to a low pressure.
The lower limit of the pressure that can be discharged is approximately 4×10 −2 Pa. The material deposited on the object to be coated is the sputtered cathode rod 2. In addition to the surface substance b, working gas may be mixed in, and in order to reduce the mixing of working gas molecules, it is desirable to reduce the working gas pressure P as much as possible, but conventional magnetron sputtering equipment The second drawback is that the lower limit of the pressure at which discharge can occur is limited to a high value as described above. SUMMARY OF THE INVENTION An object of the present invention is to provide a sputtering device that has high sputtering energy efficiency and can extremely lower the lower limit of the pressure that can be discharged.

The present invention improves the stability of the discharge by arranging the anode along the entire length of the center electrode in the longitudinal direction, thereby increasing the discharge voltage, increasing the energy efficiency of sputtering, and lowering the lower limit of the pressure that can be discharged. This objective was achieved by making it possible to achieve a very low temperature, and at the same time, the sputtered material could be effectively used for coating. Examples of the present invention will be described in detail below. FIG. 4 is a sectional view of a sputtering apparatus showing an embodiment of the present invention. Reference numeral 1 denotes two parallel plate-shaped end pads, which are arranged perpendicularly to the end pads between the end pads 1, and at least the surface of which is formed with a central electrode 2 made of a desired sputtering material and a cathode K. Configure.

5 are two annular anode end members arranged parallel to each other,
Eight blade bodies 6 are fixed between the two anode end members 5,
The anode end member 5 and the blade body 6 together constitute an anode, and the anode A is spaced apart from the cathode K over the entire length in the longitudinal direction except for the vicinity of the end pad 1 of the center electrode 2. It will be arranged as follows.

A magnet 7 applies a magnetic field substantially parallel to the axis of the central electrode 2 to the space surrounded by the cathode K and the anode A.

8 and 9 are conductor pillars fixed to an insulating support 10,
The conductor 8 is a conductive path to the cathode K via a power supply terminal (not shown) connected to the flange 11, and also supports the cathode K.

The conductor column 9 is a conductive path to the anode Δ via the power supply terminal (not shown) connected to the flange 11, and supports the anode A. Thus, the anode Δ and the cathode K are supported insulated from each other, and a discharge voltage a is applied between them.
can be applied, and a magnetron sputtering device is configured. The anode end member 5 and the blade body 6 constituting the anode, that is, the anode has a gap configured so that more than half of the center electrode 2 can be directly viewed from the outside, except for the longitudinal ends of the anode. . In this embodiment, this gap is formed in a linear shape. The effects of the present invention will be explained with reference to the embodiments of the present invention shown in FIGS. 4 and 5. The anode Δ is arranged around the center electrode 2 over its entire length except for the vicinity of the end pad 1. This has the effect of significantly improving the stability of discharge.

That is, in the present invention, the electron group formed in the anode internal space that characterizes magnetron discharge is stabilized by the presence of the anode, which is previously disposed outside the entire discharge space, and the first
The present invention suppresses instability near the outer periphery of the electron group due to the absence of an anode within the wide gap between the two annular anodes 3 shown in the figure, thereby stabilizing the discharge. That is, since the end pad 1 constitutes the cathode K at both ends of the anode A together with the center electrode 2, a potential barrier against electrons is created near both ends of the anode A facing the end pad 1, and the magnetic field by the magnet 7 is By this action, the electron group can be confined in the anode internal space and the magnetro 7 discharge can be maintained stably. As a result of this action, firstly, the discharge is stable even if the discharge voltage is increased, and if necessary, 5K
V or higher, and the energy of the ions bombarding the center electrode can be increased, resulting in an effect of improving the energy efficiency of sputtering. This effect can be further enhanced by increasing the strength of the magnetic duck created by the magnet 7. Second
The effect of this is that the lower limit of the working gas pressure at which discharge is possible can be made very low, and discharge is possible even when the pressure is lowered to the border of the ultrasonic vacuum region of the high vacuum region. The sputtering apparatus of the present invention constructed in this manner maintains the effect of increasing the energy efficiency of the sputtering ratio by providing a gap in which more than half of the center electrode can be directly viewed from the outside of the anode. . Although the anode shown as an example in FIGS. 4 and 5 has linear voids, it has the effect of not impairing the uniformity of the coating, but for that purpose, voids of other shapes may be used. If uniformity is not an issue, the voids may be linear.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the main parts showing an example of a conventional magnetron sputtering device, Figure 2 is a diagram showing the relationship between the current density flowing into the center electrode and the discharge voltage, and Figure 3 is the working gas pressure. FIG. 4 is a sectional view of a sputtering apparatus showing an embodiment of the present invention, and FIG. 5 is a sectional view taken along line MM in FIG. 4. 1... End pad, 2... Center electrode, 3... Annular anode, 4... Line of magnetic force, 5... Anode end Member, 6... Wing body, 7
...Magnet, 8,9...Conductor column, 10.
...Support, K...Cathode, A...
·anode.

Claims (1)

[Claims] 1. A cathode is constituted by a tubular anode, first and second end hats provided close to the tube end of the anode, and the first and second end hats. a center electrode made of a material that is held by end hats and extends to the axial center of the anode, and whose surface is sputtered; and a magnetic field generator that applies a magnetic field parallel to the axial center of the anode tube. A sputtering apparatus comprising: a gap provided around the outer periphery of the anode through which 1/2 or more of the center electrode can be directly viewed from the outside of the anode. 2. The sputtering apparatus according to claim 1, wherein the outer periphery of the anode is formed of a wire. 3. The sputtering apparatus according to claim 1, wherein the outer periphery of the anode is formed of a spiral wire body.