JPS58221276A - Sputtering device - Google Patents

Abstract

PURPOSE:To assure the required amt. of the reactive gas in the erosion area near a target and to minimize the amt. of the reactive gas near a substrate, by forming the ejection ports for the reactive gas and a target shield into one body and disposing the same at the distance near the target. CONSTITUTION:A target 1 adhered onto a backing plate 201 is supported isolatedly by means of a support base 2 disposed on the base plate 12 of a bell-jar 11. A target shield 4 is disposed around the plate 12 and the target 1 isolatedly from the base 2. Ar is introduced through an introducing valve 9, and a reactive gas is ejected through an introducing valve 8 and an introducing pipe 801 directly to the target 1 from plural ejection ports 401 provided to the shield 4. Abnormal electric discharge is thus prevented and the partial pressure of the reactive gas is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a sputtering apparatus, and particularly to the structure of a target shield.

Technical background of the invention and its problems This is a method of attaching particles to a substrate to form a thin film. It has the advantage that thin films of oxides, nitrides, carbides, etc., which are difficult to form using vacuum evaporation, can be easily formed. In reality, however, the magnetron method, which uses magnets to create orthogonal electromagnetic fields on the target to increase the gas ionization efficiency and speed up the sputtering speed of the film, is common, and has been put into practical use and its industrial applications are expanding. ing. Argon (hereinafter referred to as Ar) is generally used as a gas for creating plasma.

Depending on the type of film to be formed, oxygen (hereinafter 02
In the case of nitrides, nitrogen is introduced, and in the case of carbides, a reactive gas such as methane is introduced in the form of Ar1C added.

Among films formed by sputtering, the following two methods are used to form, for example, an oxide film.

One is sputtering using a metal target in a mixed gas atmosphere of O2 and Ar. One method is sputtering with Ar using a target made from an oxide of the material. Generally, the former changes from a metal to an oxide depending on the proportion of 020 in Ar, and requires a large amount of 02. Although the latter has drawbacks such as difficulty in producing a highly pure and homogeneous oxide target, stable oxides can be sputtered in an Ar atmosphere and can be easily controlled. However, easily decomposed oxides require the introduction of a reactive gas, ie 02.

For example, in ZnO, TJO, 8nO, Ta, O, etc., the composition of the separated AI film deviates from its stoichiometry and changes from an insulator to a semiconductor. To prevent this, sputtering is performed in a mixed gas atmosphere of 0□ and Ar.

However, in general, the amount of reactive gas in the mixed gas atmosphere of reactive gas and Ar must be sufficient to maintain the stoichiometry of the deposited film and to suppress decomposition of the target surface. . However, increasing the amount of reactive gas in the sputtering apparatus, particularly between the substrate on which the film is to be formed and the target, slows down the film formation rate. As an example of this, T
The relationship between the oxygen partial pressure of a, O, and the sputtering rate is shown.

The sputtering conditions at this time are that the pressure of the mixed gas of o2 and Ar is 2.66X10-'Pa, the sputtering power is itcw, and the diameter of the target is 20oIII+.
This is the case when the test was carried out using a disc.

Furthermore, in general, on the target surface in the magnetron method, the concentration of plasma is generally high at the location where the magnetic field is parallel to the target, and sputtering is concentrated. This area is usually called the erosion area, and this area is mostly near the target and is usually thick. This area is especially prone to decomposition.

That is, if the amount of reactive gas is insufficient, this region becomes conductive and abnormal discharge such as arc discharge occurs, resulting in splash that is mixed into the film and eventually melts the target surface and causes cracks. Therefore, even if the rate of film formation by sputtering is slow, the amount of reactive gas in the sputtering apparatus must be increased to ensure the required amount of reactive gas in the erosion area near the target surface. That is, the reactive gas partial pressure within the sputtering apparatus becomes higher than necessary, and the film formation rate becomes slow.

Incidentally, an oil diffusion pump is usually used as a means for evacuation. This is the principle of boiling the gas before diffusion and ejecting it from a jet to exhaust gas molecules. Especially for reactive gases. When using a conventional sputtering apparatus, there is a drawback that the heated pre-diffusion reacts with the 02 and the deterioration of the oil is stopped. Moreover, even if a silicone system resistant to oxidation is used before diffusion, such deterioration is difficult to avoid and frequent replacement is required before diffusion. For example, the first
If sputtering is continued by introducing the amount of oxygen partial pressure 1.33×10 Pa shown in the figure, the lifetime before diffusion becomes approximately 1/4 to approximately IA of that when oxygen is not used. In other words, as the amount of O2 increases, the life before diffusion becomes shorter.
There were cases where l was used.

Purpose of the Invention The present invention is based on sputtering in a mixed gas atmosphere of reactive gas and Ar with a reactive gas partial pressure higher than necessary in order to prevent abnormal discharge such as arc discharge in the erosion area near the target. This was done in order to eliminate the drawback of slow film formation speed, by integrating the reactive gas nozzle and the target shield, and placing this integrated product close to the target to reduce the reactive gas in the erosion area near the target. The purpose of the present invention is to provide a sputtering apparatus that secures the necessary amount of reactive gas and minimizes the amount of reactive gas within the sputtering apparatus, especially near the substrate.

Summary of the Invention According to the sputtering apparatus of the present invention, a reactive gas ejection port and a target shield are integrated, and this integrated structure is placed close to the target to reduce the required amount of reactive gas in the erosion area near the target. The amount of reactive gas in the sputtering equipment, especially near the substrate, is minimized while ensuring the same. This increased the rate of film formation by sputtering.

Embodiment of the Invention An embodiment of the sputtering apparatus of the present invention will be described below with reference to FIG.

Targeter consisting of an insulated conductor supporting a target (1) glued onto a backing plate (201)
Support stand (2) is arranged on the base plate α of the Kaheru jar αθ. A target shield 4) is disposed around the backing plate (201) and the target (1), keeping the target support stand (2) and the target shielding structure stable. This target shield responsibility 4) Ba target (1
), and this substrate holder (6) is placed on the base plate (17J) by a holder support rod (7).
r is introduced into the sputtering apparatus from the Ar introduction valve (9), but the reactive gas, for example 02, is introduced from the reactive gas introduction valve (9).
8) and passes through a reactive gas introduction pipe (801), and is sprayed directly onto the target (1) from a plurality of spout ports (not shown) provided in the target shield (4). In this way, the required concentration of reactive gas in the erosion area near the target (1) is ensured, the partial pressure of the reactive gas between the substrate (5) and the target (1) is lower than in the conventional method, and the film formation rate is increased. Faster than the conventional method. Also, the vacuum evacuation inside the sputtering equipment is:
'This is carried out using an oil diffusion pump (not shown) through the opening (3).

Next, the plurality of ejection ports of the target shield element 4) will be explained with reference to FIGS. 3 and 4. In FIG. 3, a plurality of jet ports (401) are provided in the cylindrical portion (404) of the target shield (4). Furthermore, the cylindrical part (40
There is an outer edge (402) on the target support stand (2) side of 4).
is formed. A support hole (403) for attaching to the target support stand (2) is provided on this outer edge (402). In Figure 4, the target shield (4
) is a cylinder with both ends open, and inside the cylinder are a target (1) glued to a backing plate (201) with adhesive N(101)- and a packing plate L/-t (201).
) is inserted. This target shield (4)
The gap between (1) and Targera) is approximately 2 to 3 degrees. In addition, the cylindrical part (404) of the target shield (4)
The wall is hollow (405), and the reactive gas introduction tube (801)
The reactive gas can be sprayed onto the target (1) from the spray hole (401) having a diameter of approximately 1 to 2 m. For example, a disc-shaped Targera with a diameter of approximately 200 m)
(1) The number of ejection holes (401) is the highest at 8 to 16 degrees, and reactive gas is efficiently supplied to the erosion area near the target surface of the magnetron method.
The purpose of preventing abnormal discharges such as arc discharges is achieved with a minimum amount of reactive gas compared to conventional methods. According to this method, the effect of suppressing the decomposition of the target surface was obtained even if the partial pressure of the reactive gas was lower than that in the conventional case. For example, the conventional pressure was 1.33×10 Pa, but with the present invention it is 6.
．． 65XIOPa would have been fine. In other words, by securing the necessary amount of reactive gas partial pressure near the target and applying a higher reactive gas partial pressure between the substrate and the target than before, the film formation rate by sputtering becomes faster than conventional methods. Ta. Furthermore, the sputtering speed with the same power was improved, and the life of the diffusion oil in the exhaust system was also extended, especially when 02 was used as the reactive gas.

Next, another embodiment of the present invention will be described with reference to FIG.

The target shield (4) in FIG. 5 is basically the same as the target shield (4) of the embodiment, except that the shape is rectangular. This target shield (4
) is intended to be applied to large rectangular targets.

Furthermore, in one embodiment of the present invention, the reactive gas, Ar and the inlet pipe (
It goes without saying that the sputtering apparatus of the present invention may be introduced from the sputtering device (according to the sputtering device of the present invention), the reactive gas outlet and the target shield are integrated, and this integrated product is placed at a close distance to the target. This makes it possible to supply the minimum necessary amount of reactive gas to the target.

This prevents abnormal discharges such as -gamma discharges occurring in the erosion area near the target, lowers the reactive gas partial pressure in the sputtering apparatus, and increases the speed of film formation by sputtering.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between 'rato' oxygen gas pressure and sputtering speed, Fig. 2 is a block diagram of a sputtering apparatus according to an embodiment of the present invention, and Fig. 3 is an enlarged view of the main parts of Fig. 2. , 4th
The figure is an enlarged schematic view of the main part of FIG. 2, and FIG. 5 is a perspective view of a target shield according to another embodiment ff1J of the present invention used for a rectangular target. (1)...Target, (2)...Target support, (4)...Target shield, sauce...Base plate, (401)...Ejection port. Agent Patent attorney Kensuke Chika (and 1 other person) (11
) Third factor Figure 1 Figure 2 Figure 4 Figure 5 μ/ l, o/ δL μj

Claims (1)

[Claims] In a sputtering apparatus, the target shield includes a target support made of a conductor placed on a base plate, a target placed on the target support, and a target shield that prevents electric discharge from going around the target. A sputtering device characterized by having a plurality of spouting ports that spout out.