JPH0527490Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a sputtering device, in particular a reaction method that forms a thin film with excellent uniformity in film thickness and high purity on the surface of a molded object to be thin film. This invention relates to a magnetron cathode for sexual sputtering.

(Prior art) Conventionally, a thin film of ceramics such as titanium nitride has been used as a thin film forming body (hereinafter abbreviated as a substrate).
A reactive sputtering method is often used as a method for forming the film on the surface.

In such a reactive sputtering method, for example, pure titanium is sputter-evaporated with argon gas ions, and while a small amount of nitrogen gas is supplied as a reaction gas, the sputter-evaporated titanium atoms are reacted with the nitrogen gas. A method is known in which titanium nitride is produced by depositing a thin film of titanium nitride on the surface of a substrate.

There is also known a method of supplying a mixed gas in which predetermined amounts of the inert gas and reactive gas are mixed in advance.

Two examples of conventional sputtering devices used in the above sputtering method will be described below with reference to FIGS. 3 and 4.

First, an example of the first conventional technique will be explained below based on FIG. 3, which is an explanatory diagram of its configuration.

That is, a sealed tank 51 is disposed in which a cathode 52 is disposed inside the upper part and an anode 53 is disposed inside the lower part with their lower and upper surfaces facing each other.

A target 54 is provided on the lower surface of the cathode 52, and a substrate 56 is detachably provided on the upper surface of the anode 53.

In the lower part of the sealed tank 51, an injection hole 60 is inserted through the outer wall of the sealed tank 51 into the substrate 56.
A reactant gas supply pipe 59 is arranged in close proximity to
Further, an inert gas supply pipe 61 is disposed in the upper part of the sealed tank 51, penetrating its outer wall, and having an injection hole 62 close to the target 54.

Further, exhaust pipes 55 and 57 which penetrate through these walls and open at the inner surface of the sealed tank 51 are provided on the side wall opposite to the penetration position of the reaction gas supply pipe 59 at the bottom of the sealed tank 51 and on the lower wall thereof. is installed.

Then, the supply of gas is stopped to each of the reaction gas supply pipe 59 and the inert gas supply pipe 61,
Further, a valve 63 for adjusting the supply amount, and an exhaust valve 58 for exhausting the gas in the sealed tank 51 are interposed in each of the exhaust pipes 55 and 57.

Further, a shutter 65 parallel to the opposing surfaces of the two poles 52 and 53 is provided between the sealed tank 51 and the shutter 65 .
The structure is such that it is supported at the upper part of a support column 66 that is erected through the lower wall of the support column 66 so as to be swingable about the vertical direction of the support column 66.

Next, pure titanium was used as the target 54 and nitrogen gas (hereinafter abbreviated as N) was used as the reaction gas.
In addition, argon gas (hereinafter referred to as Ar) is used as an inert gas.
The operation of this technique when using the following will be explained below.

A predetermined amount of N is introduced into the sealed tank 51 from the reaction gas supply pipe 59 by adjusting the opening degree of the valve 63.
Further, when a voltage is applied to the cathode 52 and anode 53 while supplying a predetermined amount of Ar from the inert gas supply pipe 61, the target pure titanium 54 is evaporated in spatters by the action of Ar, and the evaporated titanium Atoms move toward substrate 56 . and,
The atoms react with nitrogen to become titanium nitride, which flies and adheres to the surface of the substrate 56, and a thin film of titanium nitride is formed on the surface of the substrate 56.

Then, when the thickness of the thin film reaches a predetermined thickness,
Application of voltage to both poles 52 and 53 is stopped,
The valves 63 of the supply pipes 59 and 61 for Ar and N are each closed, and the exhaust valve 58 is opened, so that the mixed gas present in the sealed tank 51 is transferred to the exhaust pipe 55.
and 57, and then, although not shown, the substrate 56 on which the thin film has been deposited is taken out from the take-out port of the substrate 56.

The purpose of the shutter 65 is to clean the surfaces of the target 54 and the substrate 56 in the initial stage.

That is, Ar and N are supplied into the vacuum chamber 51, the shutter 65 is positioned between the two electrodes 52 and 53, and a negative voltage is applied to the anode 53 and a positive voltage to the cathode 52 to prevent foreign matter from adhering. The surface of the substrate 56 whose surface is contaminated is evaporated by spatter, and the atoms of the substrate 56 evaporated by the spatter are transferred to the shutter 6.
Shield with the surface of 5. Next, a positive voltage is applied to the anode 53 and a negative voltage is applied to the cathode 52 to sputter evaporate the surface of the target 54 whose surface is contaminated.
After shielding the spatter-evaporated atoms on the surface of the target 54 with a shutter 65 and cleaning the surfaces of the substrate 56 and the target 54, the shutter 65 is oscillated and evacuated from between the poles 52 and 53. As a result, a normal thin film is formed on the substrate 56.

Next, the differences between the second conventional technique example and the first conventional technique example will be explained below based on FIG. 4, which is an explanatory diagram of the configuration thereof.

That is, in the first conventional technique, the sealed tank 51
In contrast to supplying N and Ar through separate supply pipes, in this second conventional technique, predetermined amounts of each of the above gases are mixed in advance, and the mixed gas is supplied to the sealed tank 51.
The two poles 52,
Shutter 6 parallel to those opposing surfaces between 53 and 53
5 is retractably supported at the upper part of a support column 66 that extends through the lower wall of the sealed tank 51.

Therefore, the opening degree of the valve 63 is adjusted, and the mixed gas supplied from the mixed gas supply pipe 64 into the sealed tank 51 easily reaches the mounting position of the target 54, so that this technique is different from the first conventional technique. It has the same effect as the technique.

(Problems to be solved by the invention) The two examples of sputtering devices explained in the previous section are
All of these methods are often used because they are said to form thin films at a fast rate, but from the viewpoint of the uniformity of the thickness of the thin film deposited on the surface of the substrate, the homogeneity of the thin film, etc. It has problems as explained in the following.

That is, in the first conventional technique, there is a difference in the partial pressure of the reaction gas between the side where the reaction gas is supplied into the sealed tank and the side where the reaction gas is exhausted from the sealed tank. Gas diffusion is not always sufficient, and the reaction gas has poor uniformity. Therefore, there is a problem that the reaction with the sputtered evaporated substance becomes non-uniform, and the thickness of the thin film deposited on the surface of the substrate becomes non-uniform.

In addition, since the injection hole of the inert gas supply pipe is located close to the target, spatter may evaporate near the injection hole and mix with the atoms of the target, resulting in impurities on the surface of the substrate. There is a problem when a thin film is formed.

Furthermore, in the second conventional technique, a mixed gas is supplied. That is, predetermined amounts of Ar and N are mixed by diffusion before supply, but diffusion mixing can take about a week, making it difficult to change the mixing ratio of the mixed gas as needed, making it an urgent task. Another problem is that it is difficult to respond to changes in conditions.

Therefore, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a magnetron cathode for reactive sputtering which allows the gas mixture ratio to be changed appropriately as needed, has excellent film thickness uniformity, and is capable of depositing and forming a high-purity thin film on the surface of a substrate.

(Means for Solving the Problems) The structure of the magnetron cathode for reactive sputtering according to the present invention is that the magnetron cathode for reactive sputtering is provided with a plurality of magnets parallel to a target for sputtering the target. A plurality of inlet holes are provided for supplying a reactive gas from the outside of the target between the target and the magnet, and the reactive gas is injected into the target toward an inert gas in a sealed tank housing the target. It is characterized by having injection holes.

(Function) In the present invention, the magnetron cathode for sputtering is constructed as described above, so that a predetermined amount of reactive gas is supplied to the space between the inside of the target and the outside of the magnet through the introduction hole. The reactive gas filling the space is injected from a plurality of injection holes toward the outside of the target at the speed of sound.

Since an inert gas is present around the outer periphery of the target, the target is sputter-evaporated normally by the action of the inert gas, and the sputter-evaporated atoms of the target are sure to react with the reaction gas. , a thin film of the reaction product with excellent film thickness uniformity is deposited on the surface of the substrate.

Further, unlike the first conventional sputtering apparatus, there is no supply pipe for a reactive gas made of a different material from the target in the vicinity of the target, so the sputter-evaporated atoms in the supply pipe will not be scattered. Furthermore, by appropriately adjusting the supply amount of the reactive gas, the mixing ratio of the mixed gas can be easily changed.

(Example) An example of the present invention is shown in FIG. 1, which is a front sectional view thereof, and
The following description will be made based on FIG. 1 and FIG. 2 which is a cross-sectional view.

That is, the reference numeral 1 shown in FIG. 1 is a tubular support 1 whose upper end is open;
Four annular magnets 2 were supported at equal intervals in the vertical direction and with the same poles facing each other. And the magnet 2
A target support 3, which surrounds the target support 3 and has a canopy and has 4 eight vertical grooves continuous in the vertical direction of the outer periphery and circumferentially spaced at equal intervals, is erected concentrically with the support 1. A supply hole 5 was bored between the outside of the target support 3 and the inside of the target support 3 for supplying cooling water from below. Further, a target 6 made of 99.999% pure titanium having a cylindrical shape with a canopy is fitted onto the support 3, and the lower end surface is brought into contact with a surface formed at the base of the support 3. The upper end supported the lower surface of Target 6's canopy.

Seven sets of eight injection holes 7 are provided in the target 6 at equal intervals in the vertical direction of the target 6, which penetrate the wall of the target 6 radially at equal intervals around the radial center. , and the opening inside the target 6 of each injection hole 7 was aligned with the position of the vertical groove 4 provided around the support 3.

Further, in each lower part of the gas chamber 9 defined by the inner circumferential surface of the target 6 and the vertical groove 4, an introduction hole 8 for supplying N supplied from the outside of the lower part was bored. Further, a coaxial magnetron cathode 10, which has a structure in which the outer periphery of a target holder 3a whose lower part of the support 3 is fixed to an electrode 6a is surrounded by a shield 6b made of an insulating material, is substantially housed in a sealed tank 11 in a hermetically sealed manner.

Further, although not shown in the drawings, a substrate is provided around the outer periphery of the target 6, which can revolve around the target 6 and is detachable.

Therefore, when N is supplied to the gas chamber 9 from the introduction hole 8, the N is ejected from the injection hole 7 provided in the target 6.

Next, when an alternating current voltage is applied to the target 6, the substrate, etc., since Ar is already present around the outer periphery of the target 6, the target 6 made of titanium is spatter-evaporated by the Ar, and the spatter evaporates. The titanium and N react with each other to produce titanium nitride.

Then, the titanium nitride scatters toward the surface of the substrate disposed around the outer periphery of the target 6, and a thin film of titanium nitride is deposited on the surface of the substrate.

Therefore, in the conventional sputtering apparatus, the quality of the thin film was uneven by 20 to 30%, but in this example, a thin film having a stoichiometric composition could be formed over the entire surface of the substrate.

Furthermore, when forming a thin film, atoms sputtered and evaporated from the target holder 3a around the lower outer periphery of the target 6 are shielded by the shield 6b and do not scatter toward the substrate, so that they are not contained in the thin film formed on the substrate. The amount of impurities contained in sputtering is extremely small, corresponding to the purity of pure titanium, which is target 6. In contrast to conventional sputtering equipment, which has a purity of 99.5 to 99.9%, in the present invention, the purity is 99.5 to 99.9%.
It was 99.99%.

Furthermore, in this example, by adjusting the supply amounts of Ar and N, the supply ratio of both gases can be easily changed, so it is possible to generate titanium nitride commensurate with the sputter evaporation amount of titanium. It has also become possible to improve the efficiency of forming titanium thin films on the surface of substrates.

In addition, cooling water is supplied between the inside of the support 3 and the outside of the magnet 2 when forming a thin film.
Since the temperature needs to be about 300°C, the purpose is to prevent the performance of the magnet 2 from deteriorating due to such high temperatures.

In this embodiment, N was supplied to the gas chamber 9 from the introduction hole 8, but a mixed gas prepared by mixing predetermined amounts of Ar and N in advance was supplied from the introduction hole 8 to the gas chamber 9. In addition, an Ar introduction hole may be provided in addition to the introduction hole 8, and a gas mixing chamber may be provided inside the electrode 6a.
It is also possible to supply and mix Ar and N into the gas chamber 9.

Furthermore, although this example describes an example in which a thin film of titanium nitride is deposited and formed on the surface of a substrate, the present invention can also be applied to other materials such as titanium carbide, titanium oxide, aluminum nitride, zirconia, and silicon oxide. Able to adapt.

Furthermore, in the target 6 of the present invention, a plurality of injection holes 7 are bored on its outer periphery, and an annular target ring with radial grooves carved around the radial center on one end surface is stacked in a stacked manner. The target 6 can also be constructed using the following methods.

In the above embodiment, an example of a cylindrical magnetron cathode was explained, but the configuration of the present invention can also be applied to the reactive sputtering device of the flat electrode facing type explained in the section of the prior art. can.

(Effects of the invention) The magnetron cathode for reactive sputtering of the invention has an introduction hole for supplying a reactive gas between the target and the magnet, and also spouts the reactive gas outward from the inside of the target. It has a configuration with multiple injection holes.

Since the present invention has the above-mentioned configuration, the mixing ratio of the mixed gas in the sealed tank can be easily changed by appropriately adjusting the supply amount of the reactive gas. Not only is it easier to adapt to changes, but it is also possible to supply a reaction gas that matches the amount of sputtering evaporation of the target using inert gas, allowing reaction products to be generated more efficiently. It has also had the effect of making it possible.

Furthermore, since an inert gas is present around the outer periphery of the target, the target is sputter-evaporated by the inert gas, and the atoms of the sputter-evaporated target react with the reactive gas ejected from the injection hole to reliably become reaction products which are scattered outward from the target. As a result, a thin film of reaction products with excellent film thickness uniformity can be deposited on the surface of a substrate disposed around the outer periphery of the target.

Furthermore, since there is no supply pipe for a reaction gas made of a material different from that of the target in the vicinity of the target, it has become possible to deposit and form a highly pure thin film on the surface of the substrate.

Therefore, according to the present invention, the gas mixture ratio can be changed as necessary, the thickness is excellent in uniformity, and a highly pure thin film can be deposited on the surface of the substrate. We were able to realize an excellent and useful magnetron cathode for reactive sputtering.

[Brief description of the drawings]

FIG. 1 is a front cross-sectional view of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken from FIG. FIG. 3 is a configuration explanatory diagram of a second reactive sputtering device. 1... Post, 2... Annular magnet, 3... Target support, 3a... Target holder, 4... Vertical groove,
5...Cooling water supply hole, 6...Target, 6b...
... Shield, 7 ... Injection hole, 8 ... Nitrogen gas introduction hole, 9 ... Gas chamber, 10 ... Coaxial magnetron cathode, 11 ... Sealed tank.

Claims (1)

[Scope of utility model registration request] A magnetron cathode for reactive sputtering is provided with a plurality of magnets for sputtering the target in parallel with the target, and an introduction hole is provided for supplying a reactive gas from the outside of the target between the target and the magnet. ,
A magnetron cathode for reactive sputtering, characterized in that the target is provided with a plurality of injection holes for injecting reactive gas toward an inert gas in a sealed tank containing the target.