JPS63227773A - Formation of film by sputtering - Google Patents

Abstract

PURPOSE:To make the thickness and compsn. of a film uniform by arranging chemically different plural unit targets to form a rod target for sputtering, relatively rotating the target at the center of a tubular base materials in the axial center and carrying out sputtering. CONSTITUTION:A rod target 5 for sputtering is formed by arranging chemically different plural unit targets 5a, 5b in the longitudinal direction so that they are insulated from each other. While the target 5 is relatively rotated at the center of a tubular base material 4 in the axial center, sputtering is carried out to form a film on the inside of the base material 4.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is particularly directed to tubular substrates among semiconductor products and parts for general industrial equipment, and a surface coating consisting of a mixed composition or a mixed layer composition is applied to the inner circumferential surface of the tubular base material. (For example, magnetic film, wear-resistant film,
The present invention relates to a method of forming a hard film, etc.) by sputtering.

[Prior art] The sputtering film forming method uses a reduced pressure gas (for example, A
r) A blow discharge state is formed by arranging a target (cathode) and a substrate (anode) facing each other with a distance between them in an atmosphere and applying a high voltage between them, and plasma positive ions formed in the discharge space are This is a method in which sputtered particles are deposited on a substrate by colliding with the target surface and emitting them from the target surface. This method is relatively easy to operate and can form a uniform thin film, and it is also possible to form a film with any composition by combining the materials that make up the target. It is widely used as a film forming method in the electronics industry.

By the way, among the methods of forming an alloy film using sputtering, the composite target method and the continuous sputtering method are currently particularly widely used. In the composite target method, for example, as shown in FIG. 4.5 (both perspective views), a unit target piece 1a is made of two or more types of pure metals (two types in the figure).

1b are arranged alternately on a support plate 2, and the alloy composition constituting the sputtered film can be arbitrarily controlled by adjusting the ratio of the product of surface area and sputtering rate. can.

Further, the continuous sputtering method is, for example, as shown in FIG. 6 (explanatory cross-sectional diagram of main parts), using a main cathode target 1x and an auxiliary cathode target 1y, applying a high voltage to each through resistors Rx and Ry to perform sputtering. Then, the constituent metals of each target lx, ly are vapor-deposited on the inner surface of a tubular base material (anode) 3 arranged around these cathode targets 1x, 1y. At this time, the resistances RX and Ry
By changing the sputtering rate of the main cathode target 1x and the auxiliary cathode target 1y, it is possible to form an alloy film of any composition by controlling the resistances Rx and Ry according to the surface areas of these cathode targets lx and ly. can do. Also, if the auxiliary cathode switch sy is turned off during this sputtering, the main cathode target lx
When the main cathode switch Sx is turned off, only the metal particles are released when the main cathode switch Sx is turned off, and only the metal particles are released when the main cathode target 1y is attacked. Only the metal particles are released when attacked by plasma positive ions, and a film consisting only of the auxiliary cathode target metal can be formed.If these operations are appropriately combined, pure metals and various compositions can be formed. It is also possible to easily form a multilayer coating in which alloys of the following are laminated in layers.

[Problems to be Solved by the Invention] However, in the case of the composite target method as shown in FIG. Therefore, if you want to change the film composition, you have to prepare a composite target 1 with a surface area ratio according to the target film composition each time, which has the disadvantage of lacking flexibility. The production itself is also complicated and labor-intensive, resulting in high costs.

On the other hand, in the case of continuous sputtering method as shown in Fig. 6,
Since the auxiliary cathode target 1y is placed in the plasma space between the main cathode target 1x and the base material (ls! Contamination is unavoidable, and a gap must be provided in the arrangement part of the auxiliary cathode target 1y for the metal particles released from the main cathode target 1x to migrate toward the base material 3. Since the coating formed on the portion of the base material 3 facing the substrate 3 is thinner than other portions, there is also the problem that a uniform coating is not formed. Furthermore, if the auxiliary cathode target 1y is made larger, a shadow will be created on the inner surface of the base material 3, and the main cathode target metal concentration in this area will be low, resulting in uneven coating composition. It is hard to say that this is a method that can respond to the current situation where demands on sexuality are becoming increasingly strict.

The present invention was made in view of these circumstances, and its purpose is to simplify the structure of the target, to use only one target, and to control the sputtering conditions to reduce the thickness and thickness. It is an object of the present invention to provide a sputtering film forming method that can form a film with a uniform composition, and can also form a composite film having a laminated structure of any composition or an alloy film of any composition as required. That is.

[Means for Solving the Problems] The configuration of the present invention that has achieved the above object is to arrange a rod-shaped sputtering target at the axial center of the tubular base material and to form a sputtering coating on the inner circumferential surface of the tubular base material. In the method of forming a rod-shaped sputtering target,
A plurality of chemically different unit target materials are arranged longitudinally and insulated from each other, and the rod-shaped sputtering target thus constructed is arranged concentrically and relatively to the tubular base material. The gist is that sputtering is performed while rotating.

[Operations and Examples] FIG. 1 is a partially cutaway perspective explanatory view showing a typical example of the present invention. This is an improved method of forming a sputtering film on the inner circumferential surface of the tubular base material 4 (the above-mentioned continuous sputtering method). Therefore, although not shown in this figure, a tubular base material 4, a rod-shaped sputtering target 5, etc. are placed in a vacuum chamber, and sputtering is performed in a reduced pressure atmosphere of approximately 10-' to 10-' Torr in the presence of Ar gas, etc. The operation is the same as the conventional method.

The unique structure of the present invention is that the rod-shaped sputtering target 5 is composed of a plurality of chemically different (two in the figure) unit target materials 5a and 5b, which are connected longitudinally and mutually. The sputtering operation is performed while rotating rod-shaped sputtering targets 5, which are arranged in an insulating manner (6 in the figure indicates an insulating material), concentrically and relative to the axis of the tubular base material 4. That is, the unit target materials 5a and 5b are insulatively combined.
are connected to a high-voltage power source V and the tubular base material 4 via variable resistors Ra, Rb and switches Sa, Sb, respectively, as shown in the figure, so that the voltage between the unit target materials 5a, 5b and the tubular base material 4 can be varied. The tubular base material 4 is relatively rotated while being controlled by resistors Ra and Rh, and the constituent materials of the unit target materials 5a and 5b are sputtered and adhered to the inner peripheral surface of the tubular base material 4. At this time, unit target materials 5a, 5 formed on the inner peripheral surface of the tubular base material 4
The film formation speeds Va and Vb of the material constituting b can be expressed by the following equations.

ω However, ω: Rotation speed (each speed) of the tubular base material 4 Sa; Sputtering rate of the unit target material 5a Sb Sputtering rate of the two unit target materials, 5b Va: Voltage between the unit target material 5a and the tubular base material 4 ■b : Voltage between unit target material 5b and tubular base material 4 αa: Surface area ratio of mini unit target a αb = Surface area ratio of unit target material 5b Therefore, when ω is small, the unit target configuration is proportional to the rotational speed of tubular base material 4 Material 5a, 5
Since the deposition rate of each of b is fast, each of them is deposited on the inner surface of the base material 4 separately and with a time difference, and as a result, each of the films is deposited alternately to form a layered film. On the other hand, when ω becomes large, the rotational speed of the tubular base material 4 is fast, so even if each unit target constituent material 5a and Sb themselves are sputtered separately, the time difference in reaching the inner surface of the base material 4 can be practically ignored. Since the amount is so small that there is no time to form separate layers, a film is formed in a mixed state, and a film in an alloy state is formed.

Each constituent material 5a when each unit target constituent material 5a, 5b is formed alternately as a layered film.

hl, 5b-Vb-ab To obtain such a film thickness ratio, the respective applied voltage ratios vb h
h-5a ・ αa Also, when ω is increased to form an alloy film, the combination Ab
Sb/vb/ab may be used to form a coating having such an alloy ratio.

Vb Ab-5a・αa As described above, according to the present invention, even when using targets 5 of the same configuration, it is possible to make the coating either layered or alloyed by changing the relative rotational speed of the tubular base material 4. Moreover, by adjusting the applied voltage ratio during operation, the film thickness ratio of the layered coating or the alloy composition of the alloy coating can be arbitrarily adjusted. When forming a layered film, for example, by turning on and off the switches Sa and Sb in FIG.
It is also possible to alternately form the coatings by Sa and Sb. If this method is used, the coating times for each layer do not overlap, so the purity of each layer can be increased, and the thickness of each layer can also be adjusted according to the switches Sa, Sb. In addition to being able to arbitrarily adjust the switching time, it is also possible to form a single layer coating consisting only of the unit target constituent material 5a or 5b, if necessary. And if you combine the various film formation methods mentioned above,
Films with various laminated structures consisting of a combination of a single metal layer and an alloy layer can be easily formed, and the combinations can be expanded infinitely.

By the way, in FIG. 1, the unit target material 5a.

5b to the common high voltage power supply V, and the variable resistors Ra,
Although an example has been shown in which the voltage ratio is adjusted by Rb, it is of course also possible to connect a high voltage power source to each of the unit target materials 5a and 5b and control the voltage with the tubular base material 4 individually. In addition, although the figure shows an example in which the axes of the rod-shaped target 5 and the tubular base material 4 are set vertically and rotated relative to each other,
As shown in FIG. 2 (schematic front view), the axis can be set horizontally and rotated (7 in the figure indicates a rotating roller), and instead of rotating the tubular base material 4, a rod-shaped target 5 can be used. It is also possible to rotate them, or in some cases, it is also possible to rotate both of them simultaneously in opposite directions or in the same direction at different speeds.

FIGS. 3(A) to 3(F) show various modified examples of the rod-shaped target 5 used in the present invention (all are cross-sectional views)
FIG. 3(A) shows four types of unit target materials 5a to 5d each having a fan-shaped cross section, which are insulatively assembled via an insulating material 6.
It is designed to be able to form an alloy coating consisting of the following components or a laminated coating consisting of four types of metals.
Seeds or five or more types of unit target materials 5a, 5b,.
It is also effective to create a composite target by combining... When using these targets 5, if voltage is applied to all unit target materials 5a, 5b...
In addition to forming a coating consisting of a mixture of components according to the number of combinations of unit target materials, by selecting the unit target material to which voltage is applied, it is possible to form a coating consisting of a mixture of two to three or more components from a single component coating to an arbitrary composition consisting of two to three or more components. It becomes possible to form a film of FIG. 3(B) is an example in which the cross-sectional shape of the entire target 5 is hexagonal, and for the same purpose, it is rectangular.

Of course, polygonal shapes such as pentagons and octagons are also possible. FIG. 3(C) shows an example in which a rod-shaped target 5 is constructed by attaching three types of arc-shaped unit target materials 5a, 5b, and 5c around a rod-shaped insulating material 6. Also, Figure 3 (D
) is an example in which the surface area of the unit target materials 5a and 5b is changed, and it is also effective to adopt such a configuration depending on the target film composition and the sputtering rate. Figures 3(E) and 3(F) are examples in which two or three types of unit target materials 5a, 5b, and 5c are arranged alternately in the circumferential direction, and are excellent for forming an alloy film with a uniform composition. It has a great effect.

As described above, there are many possible combinations of the rod-shaped targets 5 used in the present invention, and all of them are included within the technical scope of the present invention. Furthermore, as is known as the coaxial magnetron sputtering method, there is a method of increasing the discharge efficiency by forming a magnetic field on a bar-shaped target in a direction perpendicular to the electrolysis. Of course, it is also possible to use a magnetic field to improve the discharge efficiency by inserting a magnetic field.

[Effects of the Invention] The present invention is configured as described above, and its effects are summarized as follows.

(1) By changing the presence or absence of voltage application to each unit target material, the magnitude of the applied voltage, or the relative rotational speed of the tubular base material, it is possible to freely select the alloy coating or laminated coating, as well as the alloy composition and lamination. The thickness ratio etc. can be easily changed, and a wide variety of sputtering films can be formed.

(2) Multiple layers of coatings can be formed continuously in a single chamber, which not only greatly simplifies the work but also promotes miniaturization of the apparatus.

(3) Since each unit target material faces the tubular base material independently, there are problems such as non-uniform film thickness and non-uniform composition due to the occurrence of "shadows" as pointed out in the continuous sputtering method in Figure 6. This does not occur at all, and it is possible to obtain an ideal sputtered coating according to the setting conditions.

[Brief explanation of the drawing]

Fig. 1.2 is a partially broken perspective explanatory view and schematic front view showing an embodiment of the present invention, and Fig. 3 (A) to (F) are schematic cross-sectional views showing modified examples of the rod-shaped target 5 used in the present invention. 4 and 5 are perspective views illustrating a composite target used in the composite target method, and FIG. 6 is an explanatory diagram showing a continuous sputtering method. 1... Composite target la, lb... Unit target piece 2... Support plate 1x... Main cathode target 1y... Auxiliary cathode target Rx, Ry... Resistor 3... Tubular base material (
Anode) Sx, Sy... Switch 4... Tubular base material 5... Sputtering target 5a, 5b, 5c, 5d ``One unit target material 6...
・Insulating material Ra, Rb...variable resistor Sa,
Sb...Switch V...High voltage power supply 7...Rotating roller

Claims (1)

[Claims] In a method of forming a sputtering film on the inner circumferential surface of a tubular substrate by disposing a rod-shaped sputtering target at the axial center of the tubular substrate, the rod-shaped sputtering target comprises a plurality of chemically different unit target materials in length. A sputtering film characterized in that the rod-shaped sputtering target configured in this manner is arranged in a dielectrically insulating manner and is sputtered while rotating the rod-shaped sputtering target relatively and concentrically with respect to the tubular base material. Formation method.