JPH06158297A - Sputtering target and its production - Google Patents

Abstract

PURPOSE:To prevent the separation of the target part from the supporting part of a sputtering target. CONSTITUTION:The target part 11 and supporting part of a sputtering target 10 are integrated by deep drawing. Consequently, the target part 11 is not separated in sputtering, a leakage due to pinholes, etc., is prevented, the material yield is increased, and the cost is reduced. A clearance is partly formed between a blank and a die in deep drawing to relieve the stress exerted on the target part in deep drawing, hence the crystal characteristic is not changed, and the target characteristic is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering target and a method for manufacturing the same, and more particularly, to a sputtering target in which a target portion and a supporting portion for supporting the target portion are integrally molded and a method for manufacturing the same.

[0002]

2. Description of the Related Art In an electronic device such as an LSI or a magnetic head, for example, a wiring whose main component is aluminum is
After being formed as a thin film of about 1 μm on the insulating layer, it is formed into a predetermined wiring pattern by lithography or the like.
A sputtering method is used for forming the thin film, and a sputtering target for this purpose is generally composed of a target member having a sputtering surface and a backing plate forming a target supporting member.

The structure of a conventional sputtering target will be described with reference to FIG. In the figure, the sputtering target is composed of a target member 3 and a backing plate 4 which forms a support member for the target member. The target member 3 is made of, for example, an aluminum alloy, has a diameter of 100 to 200 mm and a thickness of 1
It has a disk shape of about 0 mm.

The backing plate 4 is made of, for example, copper, stainless steel or aluminum, and has a disk-shaped top portion 4.
1, a skirt portion 42 extending in a hollow cylindrical or conical shape from the outer edge of the top portion 41 downward in the drawing, and a skirt portion 42 extending from a lower edge portion of the skirt portion 42 and arranged in parallel with the top portion 41. And a flange portion 43 to be formed. A bolt hole (not shown) for mounting is formed in the flange portion 43. The top 41 of the backing plate 4 has a sputter surface 3
The target member 3 is joined to the lower surface of the target member 3 on the side opposite to 1 via a solder material to support the target member.

In the sputtering target, the flange portion 43 of the backing plate 4 is generally bolted to a predetermined position on the outer wall of the vacuum chamber. The sputtering surface 31 of the target member 3 is irradiated with the ions accelerated in the vacuum chamber, and the atoms forming the target member are knocked out from the sputtering surface 31. The atoms are deposited on the wafer to form a thin film, which is directed to the wafer which is arranged to face the vacuum chamber. Cooling water is supplied to the internal space 5 of the backing plate 4 in order to prevent the temperature of the sputter surface 31 from rising.

[0006]

In the sputtering method, in recent years, in order to increase the thin film formation rate, a high sputtering power is adopted at the time of ion acceleration, and the target member tends to become larger and larger. For this reason, the temperature rise of the sputter surface becomes larger than that of the conventional one, and the temperature of the joint between the target member 3 and the backing plate 4 often rises above the melting point of the solder. In such a case, melting of the solder may cause the target member 3 to separate from the backing plate 4 and stop the sputtering.

Conventionally, in the case of a small sputtering target, a method is also adopted in which a thick plate is manufactured by plastic working such as forging, and this is processed into a deep plate shape by grinding etc., and the target portion and the supporting portion are integrally formed. Has been done. According to this method, the problem of peeling of the joint does not occur. But,
In this case, since the amount of material to be ground is extremely large, the time required for grinding is long, especially for large sputtering targets.
There is also a problem that the yield of the material is bad.

In order to prevent peeling at the joint between the target member and the backing plate, a method of joining both members by a welding method such as electron beam welding can be considered instead of solder joining. However, in the welding method, the members are melted at the time of joining, so that there is a possibility that pinholes are generated in the backing plate. The pinholes in the backing plate cause leakage due to high vacuum in the vacuum chamber and water pressure of cooling water during sputtering.

In view of the above, the present invention has a good yield of the material without fear of the target portion and the supporting portion being separated from each other even when a large temperature rise occurs, and the sputtering is less likely to occur during the sputtering. An object is to provide a target and a manufacturing method thereof.

[0010]

In order to achieve the above object, the sputtering target of the present invention is made of a metal or an alloy, is provided with a target portion and a support portion for supporting the target portion, and is formed from a single plate material. It is characterized by being drawn.

The method of manufacturing a sputtering target according to the present invention is the method of manufacturing a sputtering target made of a metal or an alloy, in which a target portion and a support portion for supporting the target portion are integrally formed by deep drawing a plate material. It is characterized by doing.

The material of the sputtering target of the present invention and the sputtering target manufactured by the method of manufacturing the sputtering target of the present invention are not particularly limited, and metals such as aluminum and titanium or various alloys are used as the material. it can.

If a clearance is provided between the portion formed as the target portion and the mold in the final step of the deep drawing process, the stress applied to the target portion is particularly reduced and the crystal in this portion is reduced. Changes in crystal characteristics such as grain size and crystal orientation can be suppressed to an extremely small level.

In one embodiment of the present invention, aluminum or aluminum alloy is used as a material, and deep drawing is performed on this material. In this case, in the molded product, the crystal characteristic of the target portion is particularly maintained in a good range, and a sputtering target that enables a good thin film formation can be obtained.

[0015]

Since the sputtering target formed by deep drawing from a single plate material is integrally formed, there is no fear of peeling of the target portion and the supporting portion due to the temperature rise during sputtering, and the deep drawing forming is also possible. The amount of grinding required for finishing to a predetermined size later is also small, and there is no fear of pinholes. Further, in deep drawing with a shallow drawing depth, the stress applied to the target portion can be made relatively small, so that the crystal characteristics of the material can be maintained relatively easily in the target portion.

[0016]

The present invention will be further described with reference to the drawings. Figure 1
FIG. 3 is an axial cross-sectional view of a sputtering target according to an example of the present invention. In the figure, the sputtering target 10 of this embodiment is made of an integrally molded aluminum alloy, and includes a disk-shaped target portion 11, a hollow cylindrical or frustoconical skirt portion 12 and a flange portion 13. Composed of and. As an aluminum alloy, for example, Si is 1 wt% and Cu is 0.5.
An alloy composed of wt%, the balance being Al and a slight amount of impurities can be used. The material of the sputtering target is
It can be appropriately selected depending on the intended wiring composition. For example, in addition to the aluminum alloy used in this embodiment, aluminum used as a wiring material for LSI or the like, or an alloy such as titanium used as a barrier metal is used.

As for the size of the sputtering target, for example, in the target portion 11, the diameter of the sputtering surface is about 30.
The skirt portion has a thickness of about 18 mm, and the flange portion 13 has an outer diameter of about 400 mm and a thickness of about 10 mm. The height from the sputter surface to the bottom surface of the flange portion 13 is about 50 mm. By adopting deep drawing, an extremely large integrally formed sputtering target can be obtained at a relatively low cost.

In the sputtering target of the above-mentioned embodiment, unlike the conventional sputtering target by solder bonding, the target portion and the supporting portion are integrally molded, so that the temperature of the bonding portion during high-speed ion irradiation with high sputtering power is high. When the temperature rises, the target portion is not likely to peel from the support portion. Further, unlike a sputtering target joined by electron beam welding or the like, there is no possibility of pinholes, and therefore, it is possible to withstand high vacuum in the vacuum chamber and pressure of cooling water. Furthermore, unlike the conventional integrally molded sputtering target, the amount of grinding after drawing is small, so
Good material yield

Further, in the conventional integrally formed sputtering target, plastic working such as forging is generally adopted in order to obtain a material having a large thickness. Therefore, it is difficult to maintain the crystal characteristics such as the crystal grain size and the crystal orientation of the material even after the plastic working, and an integrally formed sputtering target capable of forming a thin film with good quality cannot be obtained. However, in the sputtering target of the above embodiment, the crystal characteristics of the material can be easily maintained by deep drawing, and the crystal characteristics of the target portion can be maintained well, so that a uniform and high-quality thin film can be formed.

In the aluminum alloy sputtering target of the above embodiment, for example, the average value of the crystal grain size in the plate material forming the material is about 0.7 mm and its standard deviation σ.
Is controlled to about 1.0. Such control is, for example,
450 ° C. to 60 for ingots produced by the continuous casting method
It can be obtained by performing heating for 5 hours or more at a temperature of 0 ° C. and performing a predetermined heat treatment such as rapid cooling with water. The average crystal grain size and standard deviation obtained in the material change little even after deep drawing at the target portion, and the characteristics close to the above values are maintained.

In order to form a uniform thin film, the crystal grain size of the target portion is preferably, for example, an average crystal grain size of 2.0 mm or less and a standard deviation σ of 1.3 or less. In the conventional integrally formed target of the forged product, even if the crystal grain size or the like of the material formed by the continuous casting method or the like is controlled, the crystal characteristics change during the plastic working due to the subsequent forging. The average grain size is about 3.2 mm, and the standard deviation σ is about 1.5. However, in the sputtering target of the present invention, the change in the crystal characteristics before and after the draw forming can be suppressed to a small level as described above, so that it is easy to control the crystal grain size within the preferable range.

Next, a method of manufacturing the sputtering target of the embodiment of the present invention will be described. First, a predetermined heat treatment is performed, and an aluminum alloy plate material having a thickness of about 25 mm, for example, whose crystal characteristics are controlled as described above by rolling is formed. A disk-shaped blank having a diameter of about 500 mm is formed from this plate material, and this is subjected to deep drawing.

FIG. 2 is a sectional view schematically showing the final stage of drawing in the step of deep drawing the blank. A disk-shaped aluminum alloy blank is deep-drawn by a die including an upper die 21 and a lower die 22. For example, steel is used as the material of the mold. As shown in the drawing, even in the final stage of deep drawing, the bottom surface of the recess of the lower die 22 and the aluminum alloy 23
A small clearance 24 is provided between the lower surface of the blank portion and the lower surface of the blank portion.

Due to the clearance 24, the stress applied to the target portion having the sputter surface in the aluminum alloy 23 to be drawn can be made smaller than that in the ordinary deep drawing. That is, in this deep drawing, since the supporting portion mainly composed of the flange portion and the skirt portion receives the compressive stress and almost no compressive stress is applied to the target portion, the crystal characteristic formed during the material processing as the aluminum alloy is Almost the same is maintained after drawing.

The deep-drawn target 23 is processed into a predetermined shape by grinding and finishing, and then washed to obtain a product. In the grinding process, the target portion 11
(Fig. 1) is ground to a thickness of about 5 mm and has a thickness of 20
It is about mm. As a result, the corner R generated during the press work is scraped off and the sputtered surface is processed into a flat surface. The outer and inner peripheral portions of the skirt portion 12 and the lower and upper surfaces of the flange portion 13 are similarly ground, so that the final skirt portion 12 has a thickness of, for example, about 18 mm, and the flange portion 13 has a thickness of, for example, about 10 mm. It In this way, machining with the same dimensional accuracy as the conventional integrally formed sputtering target is performed.

Conventionally, there has been no example of integrally forming a target portion or a target member of a sputtering target and a backing plate forming a supporting portion by deep drawing. However, according to the method for manufacturing a sputtering target of the present invention, by adopting integral molding by deep drawing, there is no fear of peeling or leakage during sputtering, and an extremely large sputtering target can be easily manufactured, and its manufacturing cost is reduced. Reduction is possible.

Further, according to the manufacturing method of the aluminum alloy sputtering target of the above-mentioned embodiment, the change of the crystal characteristic on the sputtered surface can be made particularly small by adopting the deep drawing method excluding the compressive stress applied to the target portion. The good crystal characteristics during material processing can be maintained almost as they are, and a sputtering target capable of forming a good thin film can be manufactured.

In the sputtering target of the above embodiment, since the drawing depth is not so deep, the stress applied to the skirt portion and the flange portion is relatively small, the work hardening is unlikely to occur, and the strength is sufficient. A support portion is formed.

Needless to say, the configurations of the above embodiments are merely examples, and various modifications and variations are possible. For example, the shape of the target portion is not limited to the disk shape, and various shapes can be adopted.

[0030]

As described above, according to the present invention,
At the time of sputtering, there is no risk of peeling between the target part and the supporting part and leakage due to pinholes, etc., and because the material yield is good, it is possible to perform highly reliable sputtering and easy sputtering. A target and its manufacturing method can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a sputtering target according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a final step of deep drawing in the method of manufacturing the sputtering target according to the embodiment of the present invention.

FIG. 3 is a sectional view of a conventional sputtering target.

[Explanation of symbols]

 10: Sputtering target 11: Target part 12: Skirt part 13: Flange part 21, 22: Mold 24: Clearance

Claims (5)

[Claims] 1. A sputtering target made of a metal or an alloy, comprising a target portion and a supporting portion for supporting the target portion, and formed by deep drawing from a single plate material. 2. The sputtering target according to claim 1, which is made of aluminum or an aluminum alloy. 3. The sputtering target according to claim 2, wherein the average value of the crystal grain size of at least the target portion is 2.0 mm or less and the standard deviation thereof is 1.3 or less. 4. A method of manufacturing a sputtering target made of a metal or an alloy, characterized in that a plate material is deep-drawn to integrally form a target portion and a support portion for supporting the target portion. Method. 5. The method of manufacturing a sputtering target according to claim 4, wherein a clearance is provided between a plate material portion forming the target portion and one of the molds in the final step of the deep drawing. .