JPH11229125A - Target for sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a target for sputtering increased in using efficiency by a simple structure. SOLUTION: In a sputtering method, a target part is composed of combination of two of a part to be consumed by erosion and an outer frame part supporting it, and also, the compsns. of the both are made the same. Further, the area in which the part to be consumed by erosion (consumed part) is brought to contact with a backing plate is regulated to >=70% the area of the whole body of the target, and the are of this part is regulated to >=1.3 times the area on the side to be sputtered in the consumed part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering target in which the use efficiency of the target is improved by dividing a target portion and replacing only a portion where sputtering erosion occurs in an industrially used sputtering method.

[0002]

2. Description of the Related Art In a sputtering method, a single-piece target material is generally used as a target material. In order to increase the cooling efficiency, a metal such as copper having excellent thermal conductivity is coated on the surface opposite to the sputtering surface with indium. Bonding using a low-temperature brazing material such as However, the portion of the target consumed by sputtering (erosion portion) is not uniform with respect to the target. In particular, in magnetron sputtering with increased sputtering efficiency, electrons are concentrated on a specific orbit by a surface magnetic field applied to the target. Therefore, it tends to be consumed locally. Such non-uniform erosion significantly reduces target use efficiency, typically between 15 and
It is about 20%. Therefore, there is no other way but to recycle or discard the used target, and there has been a problem that the cost is extremely high especially when expensive metal is used.

[0003]

The problem to be solved by the present invention is to improve the use efficiency by using a specific combination of target structures.

[0004]

SUMMARY OF THE INVENTION The present invention has been devised in order to solve the above-mentioned problems, and separates a target into two parts, an outer frame part and a large erosion part. By replacing this part with the erosion part considered as a consumable material, it is possible to substantially increase the target use efficiency. At this time, the outer frame portion and the target erosion portion are made of the same material in order to reduce distortion caused by expansion of the target material due to thermal history during sputtering. FIG. 1 shows a cross-sectional view of a sputtering target according to the present invention. As described above, the present invention includes a consumable portion that receives erosion by sputtering and an outer frame portion that does not receive erosion. In the present invention, the area of the cooling surface where the consumable part is in contact with the backing plate (denoted by A in the figure) is 70% of the entire area of the target.
The above ratio is set. Furthermore, the area (A) of the cooling surface in the consumable part is set to be 1.3 times or more the area of the consumable part on the side to be sputtered (indicated by B in the drawing). After the erosion has progressed, replacing the erosion part can substantially improve the target use efficiency, thereby significantly reducing the target cost, and disposing of the used target. Recycling becomes easy, and it is extremely useful from the viewpoint of environmental problems. 2 are a top view of the present invention (the sputtering surface is the upper surface), FIG. 3 is a rear view (the cooling surface is the rear surface), and FIG. It shows a state of a cross section of a target portion when the erosion progresses and erosion occurs. When the tip of the erosion portion reaches the vicinity of the cooling surface, the sputtering can be continued by replacing only the consumable portion. Thereby, it is possible to improve the use efficiency of the consumable part.

[0005]

The target according to the present invention is composed of two parts, an outer frame part which is hardly affected by erosion and a consumable part (erosion part) which strongly receives erosion. When the erosion progresses, the consumable part is replaced. This improves the target use efficiency. At this time, the materials of the target outer frame portion and the consumable portion are made of the same material. As a result, the coefficients of thermal expansion of the two are made equal, and the deformation of the target during sputtering is suppressed. If the two are made of different materials, a difference occurs in the coefficient of thermal expansion, and the target is deformed by thermal deformation during sputtering, whereby the cooling of the target is deteriorated and melting occurs. Further, by making this material the same, it is possible to prevent impurities from being mixed even if the outer frame portion is sputtered.

Next, the area of the consumable part in contact with the cooling backing plate (denoted by A in FIG. 1) is 70% or more of the area of the entire target including the consumable part and the outer frame part in contact with the backing plate. To have a ratio. This is because the consumable portion undergoes severe sputtering erosion, so that the temperature rise is large, and if the area in contact with the cooling backing plate is not increased, deformation occurs due to heat. If this area is less than 70%, depending on the target material and sputtering conditions, the consumable part becomes extremely hot, thermally deformed, and there is a difference in expansion between the outer frame part where the temperature rise is relatively small. Also, the outer frame portion may be deformed.

Finally, the area of the part where the consumable part and the backing plate are in contact (indicated by A in FIG. 1) is 1.3 of the area of the consumable part on the side to be sputtered (indicated by B in FIG. 1). Be more than twice. This is also necessary in order to efficiently cool the heating by sputtering similarly to the above. If this area is less than 1.3 times, the area of the part to be cooled becomes too small as compared with the area of the part to be sputtered, and the consumable part is heated, which may cause deformation of the target. If the cooling surface of the consumable portion is at least 1.3 times as large as the sputtering surface, cooling is sufficiently performed and thermal deformation of the target is suppressed. Further, in order to suppress the thermal deformation as described above as much as possible, it is effective to improve the heat transfer between the cooled backing plate and the target, and from that viewpoint, as in the invention of the present inventors, The cooling effect can be improved by sandwiching a thin plate or foil of aluminum and their alloys between the target and the backing plate.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The object to be coated by the present method is not particularly limited, such as a plate and a powder. A method of coating particles (powder) by sputtering is possible according to, for example, JP-A-2-153068 filed by the present inventors. For details, put the predetermined powder in the rotating barrel,
Coating can be performed by applying the sputtered particles while stirring. The present invention is also effective when a reactive sputtering method is used for coating an oxide, a nitride, a carbide, or the like. In addition, the outer frame portion according to the present invention can be repeatedly used (reused) even after sputtering if there is no damage. Such a method is inexpensive and easy, and its effects are not limited to reduction of target cost and improvement of target use efficiency, but also improvement of manufacturing process efficiency, improvement of equipment maintenance, improvement of product quality, There are industrially very large targets, such as improved recyclability of the target.

[0009]

[Example 1] Ti was sputtered on a glass substrate at an output of 1 kW and a sputtering pressure of 1 × 10 ^-2 Torr (1.3 Pa). FIG. 5 shows the relationship between the accumulated sputtering power per target and the usage efficiency of the target consumable part. The target used in this example was:
The total area (S) is 90cm ² , the area of the cooling surface of the consumable part (S1)
There 70cm ^2, an area of the portion to be sputtered of the consumable section (S2) was 50 cm ^2. The target thickness is 10mm
It is. From the figure, one consumable part was replaced when the total power reached 70 kWh. The figure also shows the usage efficiency obtained from the change in weight of the entire target including the outer frame of the target. From these results, according to the present invention, the use efficiency of the consumable part can be improved to 55%, and the use efficiency of the entire target improves as the consumable part is replaced, and when the power amount is 150 kWh, It was found to be improved to about 40%. In addition, the usage efficiency in the case of using the conventional integrally molded target material was about 20%. Therefore, it can be seen that the target use efficiency can be improved twice or more by this method.

[Example 2] Coating was performed by the sputtering method under the same conditions as in Example 1. At this time, the total area (S) of the target was 90 cm ² , the area (S1) of the cooling surface of the consumable part was changed, and the relationship between the S1 / S ratio (expressed in%) and the thermal deformation of the target was examined. The area (S2) of the consumable part to be sputtered is 70% of S1, and the target thickness is 10 mm. At this time, when the sputtering power amount was 50 kWh, the case where the target was thermally deformed was evaluated as x, and the case where the target was not thermally deformed was evaluated as ○.
The result is shown in FIG. From this result, it can be seen that no thermal deformation occurs when S1 is 70% or more of S as in the present invention.

[Example 3] Coating was performed by the sputtering method under the same conditions as in Example 2. At this time, the total area (S) of the target was 90 cm ² , the area (S1) of the cooling surface of the consumable part was 75 cm ^2, and the area (S2) of the sputtered part of the consumable part was changed. The target thickness is 10 mm. At this time, the relationship between the S1 / S2 ratio and the thermal deformation of the target was examined in the same manner as in Example 2. The result is shown in FIG. From this result, it is understood that thermal deformation does not occur when S1 / S2 is 1.3 or more as in the present invention.

[0012]

As described above, according to the present invention, the effective use efficiency of an effective target can be improved inexpensively and easily. The above effects have many advantages such as reduction of target cost, improvement of work efficiency, simplification of maintenance management of manufacturing equipment, improvement of product quality, and improvement of recyclability of used target. large.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a target (a side cross-sectional view of FIG. 2) illustrating the present invention.

FIG. 2 is a schematic top view of a target according to the present invention.

FIG. 3 is a schematic rear view of a target according to the present invention.

FIG. 4 is a schematic cross-sectional view of a target when erosion progresses in the present invention.

FIG. 5 summarizes the results of Example 1.

FIG. 6 summarizes the results of Example 2.

FIG. 7 summarizes the results of Example 3.

Continuing from the front page (72) Inventor Yosuke Tanaka 1 at 7-Takaya-Shinmachi, Ichikawa-city, Chiba Prefecture Inside Nisshin Steel R & D Co., Ltd. Steel Technology Co., Ltd.

Claims (1)

[Claims] The sputtering target is composed of a combination material of a portion consumed by erosion and an outer frame portion supporting the same, and the composition of both is the same, and the area of the sputtering target in contact with the cooling backing plate is: The ratio of the area where the consumable part contacts the backing plate is 70% or more, and the area where the consumable part contacts the backing plate is at least 1.3 times the area of the part that does not contact the backing plate, and the target erosion proceeds. After that, the consumable part can be replaced with a sputtering target.