JPH0210863B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to sputtering targets for forming thin films of multi-component alloys or compounds.

BACKGROUND ART Examples of conventional targets for forming alloy thin films include those shown in FIG.

In other words, there is a target b in which a ring-shaped thin plate 14 of other constituent metals is placed on a disc-shaped target 10 made of a metal as the main component of the thin film, and a composite target c in which a metal ring 15 is embedded in the target surface. There is.

Problems to be Solved by the Invention However, with any composite target having such a configuration, if continuous sputtering is performed for a long period of time, the main component metal may not be sufficiently sputtered on the surface of the disk-shaped target inside the ring-shaped metal. What cannot be removed tends to accumulate as deposits 16. The components of this deposit 16 are spatter gas.
In the case of inert substances such as Ar and Ne, it is the main component metal of the target, but in the case of O ₂ and N ₂ etc., it is a compound thereof. Therefore, when this deposit accumulates, the composition of the target surface changes, and if the deposit has insulating properties, it becomes increasingly difficult for only the inside of the ring to be sputtered.

All of these phenomena cause fluctuations in the composition of the desired alloy thin film, and are particularly detrimental when attempting to obtain a stable composition during continuous sputtering over a long period of time in the manufacturing process.

Possible causes of this accumulation of deposits are as follows. Figure 5 shows the target of the high frequency magnetron sputtering device.
Once the incident sputtering gas ions 17 sputter the surface particles of the disc-shaped target, their energy is lost, but by gaining energy again by the electric field 18, the sputtering can be repeated many times. The orbit of sputtering gas ion 17 is
In the case of a magnetron sputter, it is determined by the direction of the electric and magnetic fields, but in FIG. 5, the trajectory is from the outside of the metal ring to the inside. Therefore, when sputtering gas ions enter the metal ring on the way from the outside to the inside, a current flows through the metal ring, and when the sputtering gas ions enter the metal ring, the potential decreases relatively. bring about an impact. Therefore, it is thought that the inside of the metal ring is less likely to be spattered, and even if it is spattered, the particles will come back and re-attach because the acceleration energy is small. At this time, in the case of reactive sputtering, some particles that have been sputtered may become attached as compounds, so
If the compound is an insulator, the inside of the metal ring will be more difficult to sputter, resulting in larger compositional fluctuations.

This phenomenon is the same even when the magnetic poles of the magnet 19 are reversed, and the trajectory of the sputtering gas ions is reversed depending on the polarity, so the re-deposition locations are reversed between the inside and outside of the metal ring. The only difference is that it becomes.

Furthermore, the same thing can be said when the eccentric magnet 19 revolves around the center of the target, as shown in FIG. 5, in order to increase the efficiency of use of the target.

The present invention has been made in view of these points, and it is an object of the present invention to form a uniform film composition of an alloy thin film on a substrate with a simple structure, and to obtain a stable composition even with continuous sputtering. .

Means for Solving the Problems The technical means of the present invention for solving the above-mentioned problems is to divide another metal ring to be placed or embedded on the target surface consisting of the main component of the thin film into multiple parts, so that the center line of the ring is It is placed at a position coaxial with the center of the target.

Effect The effect of this technical means is as follows.

That is, in the above configuration, since the metal ring on the target surface is multi-divided, the current flowing when sputtering gas ions are incident on the metal ring becomes extremely small. Therefore, the potential does not drop uniformly on the inside or outside of the metal ring, and the redeposition of spatter particles due to this is extremely reduced. Therefore, even if continuous sputtering is performed, an alloy thin film with a stable composition can be easily formed.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the accompanying drawings. In FIG. 1, a metal target body 2 of Te is bonded onto a backing plate 1 made of copper or stainless steel with a bonding layer 3 made of an alloy material mainly composed of In. On top of such a metal target 4, a metal different from Te,
For example, single metals such as Pd, In, Sn, Au, and Ge are placed as divided pieces 5 obtained by dividing a ring-shaped thin plate into 16 pieces. When all of these divided pieces 5 are lined up, they form a substantially ring shape and are arranged coaxially with respect to the center of the target. It is necessary that the gaps between each divided piece do not touch each other,
It was experimentally confirmed that there is no particular problem as long as the value is 0.5 mm or more.

With the target configuration as described above, even if sputtering gas ions are incident on a metal segment, the current that flows is limited to that range and does not reach the adjacent segment. Therefore, less current is lost,
There is also no relative potential drop inside the ring shape. With such a target, there were almost no attached particles, and a stable thin film composition was obtained.

For the reasons mentioned above, the larger the number of divided pieces, the greater the effect, but it was confirmed that if the number of divided pieces is 8 or more, the influence of the drop in potential is almost eliminated.

Furthermore, the arrangement of the divided pieces requires that the center line of the ring shape, which is the sum of all the divided pieces, is coaxial with the center of the disc target. this is,
The optimum diameter of the ring shape is determined theoretically from the relative positional relationship between the target and the substrate on which the thin film is formed, and by doing so, the composition in the radial direction on the substrate can be kept within a variation range of 2 to 3%. This is because it can be done as follows.

In particular, in the manufacturing process, the above-mentioned coaxial arrangement is essential in order to arrange a large number of substrates on a disk target and improve mass productivity with one sputtering process. For example, if the height from the target surface to the substrate surface is 90 mm and the eccentric distance from the center of the target to the center of the substrate is 90 mm, the optimum radius of the ring shape is approximately 40 mm. Therefore, by changing the width of the ring around this diameter,
The composition ratio of a desired thin film can be finely adjusted. Regarding the uniformity of the thin film, it is not only possible when the plasma discharge area is fixed on the same axis, but also when the discharge area is rotated about the target center because it is a ring shape with a constant width centered on the optimal radius. , the composition ratio of the target body and the divided pieces is stable, and a product with no particular problems in terms of characteristics can be obtained.

As for the material of the target body as mentioned above,
In addition to Te, Al, Ag, Au, Bi, Cu, Ge, In, Ni,
Single metals such as Si, Sn, Ti, Zn, Al ₂ O ₃ ,
_{Bi2O3 ,} CdS, _{In2O3 ,} ITO, PbO, SiC, _{Si3N4 ,}
There are alloys, compounds, and nonmetallic materials such as SiO ₂ , SnO ₂ , TiC, TiO ₂ , ZnS, and ZnSe.

Similarly, as the material for the metal segment placed on the target surface, in addition to Pd, In, Sn, Au, Ge, etc., the above-mentioned single metals, compounds, and other materials may be used. These materials are selected so that the material that constitutes the main component of the alloy or compound thin film is selected for the target body, and the material that is a minor component of the other material is selected as the material for the divided pieces.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows the same structure as in the first embodiment.
There is a metal target of Te, on which the divided pieces A, B, 8, and 9 made of two types of single metals different from Te, for example, Sn and Ge, do not touch each other and their centers are coaxial. placed above.
The size of these divided pieces is determined by the composition ratio of the thin film, and they can be of various sizes, but in order to make the composition of the thin film uniform, it is necessary to match each divided piece to the type of metal. They must be arranged alternately and in good order.

Next, a third embodiment of the present invention will be described with reference to the drawings. Figure 3 shows 3
Divided pieces a, b, c of seed elemental metals Au, Sn, Ge,
11, 12, and 13 are placed in different ring shapes, and each divided piece is arranged coaxially with respect to the center of a disc-shaped target.

The width of these ring-shaped divided pieces is selected in accordance with the composition ratio, with the diameter of the substrate being uniform in the radial direction. It is preferable that the position of each ring-shaped divided piece be determined on the inside or outside side, taking into consideration the spatter rate of the single metal. for example,
For materials with a high sputtering rate, such as Au, it is easier to make the composition distribution uniform if the material is placed at a position away from the substrate on which the thin film is formed, that is, at a position closer to the inside of the target.

In this embodiment as well, the ring-shaped divided pieces do not come into contact with each other and are subdivided, so that compositional fluctuations do not occur due to a drop in potential.

In each of the above embodiments, a case has been described in which a single metal is placed on a disk-shaped target, but it goes without saying that the same effect as described above can be obtained even when a single metal is embedded in the target surface.

Effects of the Invention The present invention provides a method for attaching a divided piece of metal, which is one of the constituent components of an alloy or compound thin film, on a target body and which forms part of a ring shape having a constant width, coaxially with respect to the center of the target. to be placed,
It is possible to form a uniform thin film and to obtain a stable composition even when subjected to continuous sputtering for a long time.

Furthermore, the present invention provides a sputtering target that has a long life even when used for long periods of time in the manufacturing process, and has great effects in stably producing high-quality thin films.

[Brief explanation of drawings]

FIG. 1 is a plan view of a target in a first embodiment of the present invention, FIG. 2 is a plan view of a target in a second embodiment of the present invention, and FIG. 3 is a plan view of a target in a third embodiment of the present invention.
4a, b, and c are plan views and cross-sectional views of the target in the conventional example, and FIG. 5 is a perspective view showing the principle of accumulation of deposits in the conventional example. . DESCRIPTION OF SYMBOLS 1... Bucking plate, 2... Target body, 3... Bonding layer, 5... Ring-shaped divided piece, 8, 9... Ring-shaped divided piece A, B, 11~
13...Ring-shaped divided pieces a, b, c.

Claims (1)

[Claims] 1. A ring-shaped target body comprising a target body made of metal, alloy, or compound, and a plurality of divided pieces of metal or alloy, each of the plurality of divided pieces having a constant width. A sputtering target, in which the divided piece is placed or embedded so as to form a part of the target body and to be coaxial with the center of the target body. 2. The sputtering target according to claim 1, wherein a plurality of divided pieces made of two or more types of metals or alloys are arranged alternately and in an order according to the type of metal. 3. The sputtering target according to claim 1, wherein each of the plurality of divided pieces made of two or more types of metals or alloys is arranged in multiple different ring shapes.