JPH04143268A - Production of target - Google Patents

Abstract

PURPOSE:To efficiently produce a clean target at a low cost by joining a metal member as a material to be sputtered and a metal member as a support part in one body and removing the surface of the former member so that a clean surface is exposed. CONSTITUTION:A first metal member 1a as a material to be sputtered and a second metal member 1b of oxygen-free copper, etc., having high heat conductivity as a support part supporting the member 1a are placed opposite to each other while interposing a spacer having a high m.p. as required. Gunpowder 3 put on the member 1a with a buffer layer 2 in-between is exploded through an exploder 4 and the members 1a, 1b are joined in one body by explosive cladding to form a target 1. The layer 2 and the contaminated surface layer of the member 1a are then removed so that a clean surface is exposed. The member 1b is worked into a prescribed shape and the members 1a, 1b are washed to obtain a target 1 having the desired shape.

Description

[Detailed Description of the Invention] [Summary] Regarding the method for manufacturing a target, the method can be made cleaner than a target using a solder material made of a low-melting brazing material, and is more efficient at a lower cost than a -shaped target. The purpose of the present invention is to provide a method for manufacturing a target capable of forming a target. A step of joining and integrating a second metal member larger than the first metal member directly or through a spacer having a higher melting point than the first metal member, and removing the surface of the first metal member. The method is configured to include the steps of exposing at least the clean surface of the first metal member, and processing the second metal member into a predetermined shape.

[Industrial application field]

The present invention relates to a method for manufacturing a sputter target used when depositing a non-magnetic or magnetic metal thin film by sputtering, which is mainly used in the semiconductor field or magnetic disk-related field. Non-magnetic materials composed of alloy-based materials such as titanium, zirconium, tungsten, molybdenum, gold, tantalum, niobium, palladium-manganese, silver, zinc, ruthenium, tellurium, and alloys containing the above materials as main components. The present invention relates to a method for manufacturing a sputter target used when depositing a metal thin film by sputtering.

Furthermore, a method for manufacturing a sputter target used when depositing magnetic metal thin films such as chromium, nickel, and their alloys, and permalloy by sputtering;
This invention relates to a method for manufacturing a sputter target used when depositing metal thin films such as silicon compounds of titanium, tungsten, and molybdenum by the sputtering method.

Non-magnetic or magnetic thin metal films used mainly in the semiconductor field and magnetic disk-related fields are now often formed by sputtering.

On the other hand, the properties of the thin film are very sensitive to the atmosphere during film formation, and residual gas components such as oxygen, nitrogen, and water in the sputtering chamber that degrade the film quality must be removed using a high vacuum pump such as a Talio pump or turbo molecular pump. Film formation is carried out in a state in which these substances are completely excluded. Recently, the requirements for the above-mentioned properties of metal thin films have become more stringent, so it has become necessary to form films as quickly as possible.

By the way, it is possible to speed up film formation by increasing the power (DC/AC) input to the sputter target, but if excessive power is input, the target will begin to thermally deform and melt, making it impossible to maintain stable film formation. . Therefore, there is a need for a method for manufacturing a target having a structure that allows efficient cooling.

[Conventional technology]

FIG. 7 is a schematic cross-sectional view for explaining a conventional target structure that is currently widespread.

In FIG. 7, 31 is a target body, 32 is a heat exchange medium such as water, which serves as a cooling medium, 33 is a support plate, and 34 is a solder material made of brazing material whose melting point is lower than that of the target body 31.

The target with this structure consists of a target body 31 which becomes the material to be buffeted, its support plate 33 (copper or copper alloy, etc.), and a solder material 34 made of a low-melting brazing material (melting point is about 200°C).
It consists of Here, the support plate 33 is in contact with the heat exchange medium 32 from the back side, and has a high thermal conductivity, so it has a function of removing the amount of heat generated during sputtering to the outside of the system via the heat exchange medium 32.

Next, a method for manufacturing the target will be explained.

First, the target body 31, which is a material to be sputtered, and the support plate 33 (copper, copper alloy, etc.) that constitutes a support part are formed into a predetermined shape.

Next, a solder material 34 made of a low-melting brazing material using an alloy containing indium or tin as a main component is placed between the surface (back surface) opposite to the sputtering surface of the target body 31, which is the material to be sputtered, and the support plate 33. 10 to 100 μm), 2
The target body 31 and the support plate 33 are attached by applying pressure while heating to about 00°C.

After removing the brazing material protruding from the periphery, a desired target body can be obtained by cleaning and removing the contamination layer on the surface of the attached target body 31. Note that whether or not the solder material 34 made of brazing material is uniformly adhered over the entire surface is confirmed by inspecting with X-rays or ultrasonic waves.

There are also examples of manufacturing targets without low-melting brazing materials. Normally, only a portion of the material to be sputtered needs to be used as the material to be sputtered, but in this case, even the support plate can be made from a material with the same composition and purity as the target material. be.

This target that does not use low melting point brazing material is made by fitting and inserting the sputter target into a support frame that is cooled with a heat exchange medium instead of a support plate, and when electric power is applied, the target thermally expands and its side parts form the support frame. It is intended to be cooled by placing it in close contact with the

Next, FIG. 8 is a schematic sectional view of a target for explaining a conventional example in which no other low melting point brazing material is used. In FIG. 8, the same reference numerals as in FIG. 7 indicate the same or corresponding parts, 41 is a packing, and 42 is a support frame.

This method is generally called a direct cooling method because the target 31 is directly cooled by the heat exchange medium 32. The target main body 31 is airtightly fixed to a support frame 42 via a gasket 41 (for example, an O-ring) at the peripheral edge of the back surface to maintain a vacuum atmosphere, and is cooled by direct contact with the heat exchange medium 32 from the back surface. It is.

[Problem to be solved by the invention]

In the conventional example using the conventional brazing material shown in FIG. It has the advantage that it can be formed into a predetermined and relatively simple shape, but if too much power is applied even when using this low melting point brazing material, the brazing material will start to melt and contaminate the vacuum atmosphere. It may deteriorate the quality of the thin film being formed, and in some cases, if the target 31 starts to peel off, abnormal discharge may occur and the target may slip off the support plate, and there is a risk of contamination from the brazing material, so it cannot be poured into the target. Electric power is limited to a range that does not melt the brazing material, so no improvement in film quality can be expected; - Low melting point brazing material is used, so the ultimate vacuum of the sputtering device cannot be increased; ■ Low melting brazing material is used. The joining process is mostly done manually and is difficult to automate, and it also has various drawbacks, such as the need to inspect each target to see if the brazing material is evenly joined over the entire surface of the target. .

On the other hand, in the above-mentioned conventional integrated type without brazing material, ■When using the thermal expansion of the target, the dimensional accuracy of the target and support frame is extremely strict, and the coefficient of thermal expansion is also taken into consideration for targets of different compositions. It is quite difficult to achieve stable cooling unless the dimensions are changed.Furthermore, in this case, cooling is achieved at the side of the target, so the side has to be made larger, which limits the shape. Furthermore,
Since the target is not fixed, the deposits on it are likely to peel off due to its expansion and contraction, and it is difficult to exhaust the gas in the minute gap between the target and the support frame, and it takes time to exhaust it to a high vacuum. , Second, in the case of direct-cooled targets, depending on the type of target, it is easy to be corroded by the heat exchange medium (usually water), which may reduce the cooling efficiency of the target during long-term use or prevent the target from being attached or detached. Sometimes they are easily scratched, and if the sealing surface is scratched, it becomes difficult to maintain an airtight seal on the surface that comes into contact with the heat exchange medium.
■In the case of precious metal targets or high-purity targets, there are various disadvantages such as the target cost being too high and ■Depending on the material, such as tungsten-molybdenum, it is difficult to process it into complicated shapes. there were.

As described above, it is not realistic to use an integrated target in mass production in terms of cost and processability.

Each of the conventional examples has these problems and is difficult to use as a target for stably forming a high quality gold lK thin film.

As mentioned above, in the conventional target manufacturing method, there was no way to reduce thermal resistance while achieving both the advantage of not using a brazing material and workability.

Therefore, the present invention provides a target that can be made cleaner than a target using a soldering material made of a low melting point brazing material, and more efficient at a lower cost than an integrated target (manufacture of a target that can form a target). The purpose is to provide a method.

[Means to solve the problem]

In order to achieve the above-mentioned object, the method for manufacturing a target according to the present invention provides a method for manufacturing a first metal member, which is a material to be sputtered, whose thermal conductivity is higher than that of the first metal member, which is a supporting part that supports the first metal member. A step of joining and integrating the second metal member, which is also larger, either directly or via a spacer having a higher melting point than the first metal member, and removing the surface of the first metal member to form a second metal member. exposing at least the clean surface of the member;
The method includes a step of processing the second metal member into a predetermined shape.

In order to achieve the above object, the method for manufacturing a target according to the present invention includes a second metal member having a higher thermal conductivity than the first metal member, which serves as a support portion for supporting a first metal member, which is a material to be sputtered.
a step of processing a metal member into a predetermined shape, and integrating the first metal member by joining it directly onto the second metal member or via a spacer having a higher melting point than the first metal member. and a step of removing the surface of the first metal member to expose at least a clean surface of the first metal member.

The first metal member according to the present invention includes aluminum or an aluminum-based alloy, titanium, zirconium, tungsten, molybdenum, gold, tantalum, niobium, palladium,
Manganese, silver, zinc, ruthenium, tellurium, and alloys containing the above metals as main components, chromium, nickel, and metals consisting of their alloys, or magnetic metals such as permalloy, and silicon compounds of titanium, tungsten, and molybdenum. Examples include metals containing at least one of the following.

The second metal member according to the present invention may be made of copper, titanium, iron, aluminum, or an alloy containing the above-mentioned metals as a main component. In this case, it is preferable to have good heat conduction and high mechanical strength.

In the present invention, the melting point of the first metal member may be lower than the melting point of the second metal member, and in this case, the second metal member that becomes the support part becomes the material to be sputtered. This is preferable because it can be made more difficult to melt due to heat than the first metal member.

In the present invention, the method of joining the first metal member and the second metal member includes the explosion bonding method as shown in FIG.
b) As shown in <HIP method, as shown in Figure 6(C) <HO
T ROLL method and Figure 6(d) 4. : As shown <HO
Examples include the T PRESS method.

C action] In the present invention, as shown in FIG. 1, a first metal member 1a serving as a substrate to be spun and a second metal member 1b serving as a supporting portion of the first metal member 1a are, for example, They are joined using the explosive bonding method, and the two are joined together at the interface. Specifically, the first metal member 1 that becomes the material to be sputtered
a and the second metal member 1b that will become the support part are processed into a relatively simple shape and then joined and integrated, and then additional machining is performed to make the target into the final shape, that is, the surface of the first metal part 13. to expose the clean surface of the first metal member 13,
After the second metal member 1b is processed into a predetermined shape, it is finally cleaned.

Therefore, it is easier to process than the conventional integrated target material, and the target can be formed efficiently at low cost. In the final cleaning process, low melting point brazing material is not used, so compared to conventional manufacturing methods, there is no elution of brazing material, so cleaning with organic solvents can be done while heating, and cleaning chemicals can be selected. can be made more clean than before.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a diagram illustrating an embodiment of the method for manufacturing a target according to the present invention. In FIG. 1, 1a is a first metal member to be sputtered, and 1b is a first metal member 1.
a second metal member serving as a support portion that supports a; l a target composed of a first metal member 1a and a second metal member 1b; 2 a buffer layer that buffers the upper surface of the first metal member 1a; 3 is gunpowder and 4 is a detonator.

Next, a method for manufacturing the target will be explained.

Here, a case will be described in which a disk-shaped target is manufactured from a rectangular member, but the same applies to cases in which targets of other shapes are manufactured.

First, as shown in FIG. 1(a), a first metal member 1a that will be the material to be sputtered and a second metal member 1b that will be the support thereof are processed in advance into a relatively simple shape, and the bonding surface is Wash it. Here, the first metal member 1a and the second metal member ib both have a length of 1000 m, a width of 500 cm, and a thickness of 1
It is processed into a 3m flat plate. The second metal member 1b is made of, for example, oxygen-free copper, and has higher thermal conductivity and mechanical strength than the first metal member 1a, which is made of, for example, Af-1% Si.

Next, as shown in FIG. 1(b), the first metal member 1a
A buffer layer 2 is provided on the upper surface of the first metal member 1a with the second metal member 1b facing each other at an interval of 3 to 5 squares, and the explosive 3 is evenly placed on the buffer layer 2 to form a detonator at the end. 4, the first metal member 1a is struck and joined to the second metal member 1b by the impact of the explosion, and the first metal member 1
a and a second metal member 1b.
is formed. At this time, the bonding interface between the first metal member 1a and the second metal member 1b has a regular waveform with an amplitude and period of about 1 square. Therefore, it was found that the contact area between the two at this portion was larger than when using a conventional solder material made of a low melting point brazing material. Furthermore, from the evaluation of tensile strength, it was confirmed that the mechanical strength of this part was comparable to that of other parts.

Next, as shown in FIG. 1(c), the buffer layer 2 on the first metal member 1a and the first metal member 1a are cut out to be larger than the final shape, and the explosive layer 2 on the first metal member 1a is made of explosive 3 used for explosion bonding. Approximately 3 m of the surface contamination layer is removed to expose the clean surface of the first metal member 1a, and at the same time, additional machining is carried out so that the outer diameter of the target has a final shape of 250 mm and a maximum thickness of 1 Om.

Next, as shown in FIG. 1(d), the second metal member 1b
At the same time, approximately 3 layers of surface contamination are removed to reveal a clean surface.
Additional machining was performed to obtain the final shape with an outer diameter of 260 tm and a maximum thickness of 15 fl, and at the same time, the seal portion was also machined.

Then, as shown in FIG. 1(e), the desired target 1 can be obtained by cleaning the target 1-1 that has reached its final shape. In addition, in the case of the conventional target manufacturing method using solder material made of low melting point brazing material, the temperature and pressure conditions during bonding are less severe than those in the present invention, and the degree of surface deformation and contamination is reduced. Since the shapes of the first metal member 1a and the second metal member 1b in the process shown in FIG. 1(a) are almost the same as in the final product,
In the conventional target manufacturing method, the above-mentioned Figure 1 (C),
The step shown in (d) is not performed.

FIG. 2 is a schematic diagram of the cathode section when the target thus manufactured is attached to a sputtering device. In FIG. 2, the same symbols as in FIG. 1 indicate the same or corresponding parts,
5 is a heat exchange medium made of water or the like, 6 is a support frame for the entire cathode assembly including magnets, etc., 6a is a flange, 7 is a packing (0 ring), 8 is an electromagnet, 9 is a flow path for the heat exchange medium 5, 9a is the heat exchange medium 5 population, and 9b is the heat exchange medium 5 outlet.

Specifically, a substrate to be processed is placed at a position facing the target 1 (not shown). The support frame 6 has a flange 6a at its opening, and a magnet 8 and its heat exchange medium 5, etc. are arranged inside. Then, the casing is airtightly fixed to the flange 6a via the gasket 7.Furthermore, the flange 6a is fixed to a sputter chamber (not shown), and the l
The interchamber is evacuated using a high vacuum pump (not shown) such as a cryopump or a turbomolecular pump until a high vacuum of o-8 to 10-'TorrO is achieved. The electromagnet 8 confines plasma near the sputtering surface of the target 1 by its magnetic field, thereby increasing sputtering efficiency (known magnetron sputtering method). A heat exchange medium flow path 9 connected to an inlet 9a and an outlet 9b of the heat exchange medium 5 is formed on the bottom surface of the support frame 6.

The spacing between the support frame 6 and the electromagnet 8 is 5 to 10 squares.

That is, this embodiment relates to a method for manufacturing a sputter target used to stably deposit a high-quality metal thin film by sputtering, and the following effects can be expected compared to conventional manufacturing methods.

■A target made of a material that is difficult to process is used to process the first metal member 1a, which will be the material to be sputtered, and the second metal member 1b, which will serve as the support material, into a relatively simple shape and then join them together. can be manufactured.

(2) Since the first metal member 1a serving as the material to be sputtered and the second metal member 1b serving as the support material are separated, the target can be manufactured at a lower cost than an integrated target.

■Compared to the conventional manufacturing method using solder material made of low-melting point brazing material, cleaning with organic solvents can be performed even while heating because there is no elution of brazing material, and cleaning chemicals can be selected more freely. The target can be made cleaner than before.

■Multiple targets can be manufactured at the same time by joining pieces of approximately 1m x 2m in size and cutting them to a predetermined size after joining, so compared to the conventional manufacturing method of each item using raw material, the target The manufacturing process can be automated and operated efficiently.

In the above embodiment, the first metal member 1a and the second metal member 1b are joined by the explosive bonding method, which is preferable in terms of mechanical strength since it can produce long objects (even if there is dirt on the joint surface). However, the present invention is not limited to this, and as shown in FIG. Since it can be joined in layers, it is preferable in terms of mass production. Specifically, as shown in FIG. 3(a), a first metal member 1a serving as the material to be sputtered (Al-1%Si) and a second metal member serving as the support portion (oxygen-free copper) are used. After processing 1b into a relatively simple shape in advance and cleaning the bonding surfaces, as shown in FIG. The first metal member 1a and the second metal member 1b are heated to a temperature of 300 to 550°C,
Bonding is performed using HOT PRESS for 60 minutes. At this time, there are 2 parts between the first metal member 1a and the second metal member 1b.
A diffusion layer 16 of about .mu.m is formed. Note that subsequent additional machining and cleaning steps for the first metal member 1a and second metal member 1b are the same as in the explosion bonding method.

Furthermore, as shown in FIG. 4, bonding may be performed by the HIP method, which is also preferable in terms of mass production, since it is possible to bond in many layers, similar to the HOTPRESS method.

Specifically, as shown in FIG. 4(a), a first metal member 1a serving as a material to be sputtered (A l -1%Si) and a second metal member serving as a support portion (oxygen-free copper) are used. 1b is processed into a relatively simple shape in advance and the joint surfaces are cleaned, and then the first metal member 1a and the second metal member 1b are brought into contact with each other, but not joined, as shown in FIG. 4(b). A buffer material 15 for preventing mutual diffusion is sandwiched between the first metal member 1a and the second metal member 1b. Next, as shown in FIG. 4(c), the temperature within the casing 17 is, for example, 350 to 550.
℃ and a pressure of 1000 kgf/-, the first metal member 1a and the second metal member 1b are
join. Note that subsequent additional machining and cleaning steps for the first metal member 1a and second metal member 1b are the same as in the explosion bonding method.

Further, the first metal member 1a and the second metal member 1b are
For example, 100 to 350°C by the OT ROLL method.
The bonding may be performed by passing it through a heated roll, and in this case, a long object can be formed, which is preferable.

In addition, in the present invention, an alloy whose main component is aluminum (
Aluminum alloy) containing at least 2% (wt%) or more of silicon (AA'-3i, Alt-3i-X) or 1 to 10% of magnesium (Al-Mg, Al
-Mg-X), hard materials are difficult to bond to the copper support plate by explosive bonding. Especially in such cases, pure aluminum
A spacer made of silver or titanium may be inserted between the first metal member and the second metal member to perform explosion bonding.

At this time, the spacer has a higher melting point than the target material. In the bonding process, in order to prevent contamination of the target material, the copper support plate and the spacer are first bonded by explosive bonding, and then the target material is bonded by explosive bonding.

Alternatively, a first metal member serving as a high-purity aluminum alloy target material and a second metal member made of pure aluminum with low purity and a spacer may be explosively bonded.

The present invention is not limited to explosion bonding, but a material that is compatible with both, such as pure silver, titanium, or nickel, is used between the first metal member 1a made of an aluminum alloy target material and a copper support plate. For example, real roll bonding may be performed using a spacer made of.

In each of the above embodiments, the first metal member 1a and the second metal member 1b are joined, the clean surface of the first metal member 1a is exposed, and then the second metal member 1b is processed into a predetermined shape. Although the case has been described, the present invention is not limited to this, and as shown in FIG. The first metal member 1a and the second metal member 1b may be joined to expose the clean surface of the first metal member 1a. In this case, the first metal member 1a, which is the material to be sputtered,
This can prevent further contamination. in particular,
As shown in FIG. 5(a), the first metal member 1a is rolled and processed into a disk shape, and a second metal member 1b serving as a support part is attached to the surface opposite to the joint surface with a heat exchange medium. After forming a groove for flowing the metal material 5, the first metal member 1a and the second metal member 1b are joined by explosion bonding, as shown in FIGS. 5(b) and 5(c). At this time, a deformation preventing table 18 that loosely engages with the second metal member 1b serving as a jacket type support portion is prepared to prevent the second metal member 1b from being mechanically deformed during explosion bonding. Then, machining is performed using the method described above.

〔Effect of the invention〕

According to the present invention, there is an effect that the target can be made cleaner than a target using a solder material made of a low melting point brazing material, and the target can be formed more efficiently at a lower cost than an integrated target. .

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining a method for manufacturing a target of one embodiment, Fig. 2 is a sectional view of a target part for explaining one embodiment, and Figs. 3 to 5 are diagrams for manufacturing targets of other embodiments. FIG. 6 is a diagram explaining each joining method in the present invention. FIG. 7 is a schematic sectional view of a target portion of a conventional example. FIG. 8 is a target for explaining another conventional example. FIG. 1a--First metal member, 1b--Second metal member, 1--Target. Figure for explaining the method for manufacturing a target of one embodiment - A sectional view of the target part for explaining the embodiment Figure 3 Diagram for explaining the method for manufacturing the target of another embodiment Figure 3 Manufacturing of the target for another embodiment Figure 4 (C) explaining the method

Claims (3)

[Claims] (1) The thermal conductivity of the first metal member (1a), which is the material to be sputtered, is higher than that of the first metal member (1a), which is the support part that supports the first metal member (1a). directly on the second metal member (1b) or on the first metal member (1b).
a) a step of joining and integrating via a spacer having a higher melting point than that of the first metal member (1a); and a step of removing the surface of the first metal member (1a).
A method for manufacturing a target, comprising: exposing at least a clean surface of the second metal member (1a); and processing the second metal member (1b) into a predetermined shape. (2) The thermal conductivity of the support part that supports the first metal member (1a), which is the material to be sputtered, is higher than that of the first metal member (1a).
a) Processing a larger second metal member (1b) into a predetermined shape; and converting the first metal member (1a) into the second metal member (1b).
a step of joining directly or through a spacer having a higher melting point than the first metal member (1a) to integrate the first metal member; and removing the surface of the first metal member (1a) to form the first metal member. A method for manufacturing a target, comprising the step of (1a) of exposing at least the clean surface. (3) The method for manufacturing a target according to claim 1 or 2, wherein the melting point of the first metal member (1a) is lower than the melting point of the second metal member (1b).