JP2019183251A - Cu-Ni alloy sputtering target - Google Patents

Abstract

To provide a Cu-Ni alloy sputtering target capable of stably depositing a Cu-Ni alloy film having uniform thickness and composition.SOLUTION: A Cu-Ni alloy sputtering target composed of Ni, Cu, and inevitable impurities has a twin crystal ratio defined as L/L×100 of between 35% and 65% inclusive, wherein L is a total length of grain boundary between crystal grains having an orientation difference between neighboring grains of 5° or more and 180° or less and Lis a length of twin crystal grain boundary of grains having an orientation difference where three lattice points are identified when rotated around the (111) plane and the (110) plane of a face-centered cubic crystal.SELECTED DRAWING: None

Description

  The present invention relates to a Cu—Ni alloy sputtering target used when forming a thin film of Cu—Ni alloy containing Ni and the balance of Cu and inevitable impurities.

The Cu—Ni alloy described above is used as a wiring film for displays and the like because it is excellent in low reflection, heat resistance, and electrical characteristics as disclosed in Patent Document 1, for example. For example, as described in Patent Documents 2-4, it is also used as a base film for copper wiring.
Furthermore, in the Cu-Ni alloy containing 40-50 mass% Ni, since the temperature coefficient of resistance is small, for example, as shown in Patent Document 5, it is used as a thin film resistor for a strain gauge.
Moreover, since this Cu-Ni alloy has a large electromotive force, it is used as a thin film thermocouple and a compensating conductor as shown, for example, in Patent Documents 6-8.
Further, Cu—Ni alloys containing Ni of 22 mass% or less are also used as general electric resistors, low-temperature heating elements, and the like.

The thin film made of the Cu—Ni alloy as described above is formed by sputtering, for example. A Cu—Ni alloy sputtering target used in the sputtering method is conventionally manufactured by a melt casting method as shown in, for example, Patent Documents 9 and 10.
Patent Document 11 proposes a method for producing a sintered body of a Cu—Ni alloy.

JP 2017-005233 A Japanese Patent Laid-Open No. 05-251844 Japanese Patent Laid-Open No. 06-097616 JP 2010-199283 A Japanese Patent Laid-Open No. 04-346275 Japanese Patent Laid-Open No. 04-290245 JP-A-62-144074 Japanese Patent Laid-Open No. 06-104494 JP, 2006-029216, A JP 2012-193444 A Japanese Unexamined Patent Publication No. 05-051662

By the way, in the above-mentioned Cu—Ni alloy film, characteristics such as electric resistance vary when the film thickness and composition vary. For this reason, it is required to form a Cu—Ni alloy film having a uniform film thickness and composition.
Further, in the Cu—Ni alloy sputtering target, when the crystal grain size becomes coarse, abnormal discharge is likely to occur, and there is a possibility that the sputtering film formation cannot be performed stably.

  The present invention has been made in view of the above-described circumstances, and provides a Cu—Ni alloy sputtering target capable of stably forming a Cu—Ni alloy film having a uniform film thickness and composition. The purpose is to do.

In order to solve the above problems, the Cu—Ni alloy sputtering target of the present invention is a Cu—Ni alloy sputtering target containing Ni, with the balance being Cu and inevitable impurities, and the difference in orientation between adjacent crystal grains Is the total grain boundary length L, and the (111) plane and the (110) plane of the face-centered cubic crystal are the rotation axes. If the length of each grid point in the case of rotating is misorientation is confirmed three grain boundaries were the twin boundaries length L _T, twin defined by _L T _/ L × 100 The ratio is in the range of 35% to 65%.

According to the Cu—Ni alloy sputtering target having this configuration, since the twin ratio specified as described above is 35% or more, the variation in the sputtering rate on the sputtering surface is reduced, and the film thickness and composition are uniform. Cu-Ni alloy film can be formed.
In addition, since the twin ratio is set to 65% or less, the occurrence of abnormal discharge during sputtering can be suppressed, and the Cu—Ni alloy film can be stably formed.

Here, in the Cu—Ni alloy sputtering target of the present invention, it is preferable that the Ni content is in the range of 16 mass% or more and 55 mass% or less, and the balance is Cu and inevitable impurities.
In this case, since the Ni content is 16 mass% or more, a Cu—Ni alloy film excellent in corrosion resistance can be formed. Further, since the Ni content is 55 mass% or less, a Cu—Ni alloy film with low electrical resistance can be formed. Therefore, it is possible to form a Cu—Ni alloy film particularly suitable for applications that require corrosion resistance and conductivity.

In the Cu—Ni alloy sputtering target of the present invention, the average crystal grain size is preferably in the range of 5 μm to 100 μm.
In this case, since the average crystal grain size is 100 μm or less, it is possible to sufficiently suppress the occurrence of abnormal discharge during sputtering film formation. Moreover, since the average crystal grain size is 5 μm or more, the manufacturing cost can be kept low.

  According to the present invention, it is possible to provide a Cu—Ni alloy sputtering target capable of stably forming a Cu—Ni alloy film having a uniform film thickness and composition.

It is a binary phase diagram of Cu and Ni. It is a schematic diagram which shows an example of the measurement result of the twin ratio of the Cu-Ni alloy sputtering target which is this embodiment. It is a flowchart which shows an example of the manufacturing method of the Cu-Ni alloy sputtering target which is this embodiment. It is a flowchart which shows an example of the manufacturing method of the Cu-Ni alloy sputtering target which is this embodiment. It is explanatory drawing which shows the measurement position of the twin ratio in the sputter | spatter surface of the Cu-Ni alloy sputtering target in an Example. It is explanatory drawing which shows the measurement position of the film thickness of the Cu-Ni alloy film in an Example.

Below, the Cu-Ni alloy sputtering target which concerns on one Embodiment of this invention is demonstrated.
The Cu—Ni alloy sputtering target of this embodiment is a Cu film used as a wiring film, a copper wiring base film, a strain gauge thin film resistor, a thin film thermocouple and a compensating conductor, a general electric resistor, a low-temperature heating element, and the like. -Used when forming a Ni alloy thin film.

  Note that the Cu—Ni alloy sputtering target according to the present embodiment may be a rectangular flat plate type sputtering target whose sputtering surface has a rectangular shape, or a circular plate type sputtering target whose sputtering surface has a circular shape. Good. Alternatively, a cylindrical sputtering target whose sputtering surface is a cylindrical surface may be used.

The Cu—Ni alloy sputtering target according to the present embodiment includes Ni and the balance is made of Cu and inevitable impurities. In addition, since Ni and Cu form a complete solid solution as shown in the binary phase diagram of FIG. 1, the content of Ni is appropriately set according to required characteristics such as corrosion resistance and electric resistance. It is preferable.
Here, in the Cu—Ni alloy sputtering target of the present embodiment, the Ni content is in the range of 16 mass% or more and 55 mass% or less, and the balance is made of Cu and inevitable impurities.

And in the Cu-Ni alloy sputtering target which is this embodiment, the length of the grain boundary formed between crystal grains in which the orientation difference between adjacent crystal grains is in the range of 5 ° to 180 ° The boundary length L is defined as the grain boundary length, which is an orientation difference in which three lattice points are confirmed when rotating with the (111) plane and the (110) plane of the face-centered cubic crystal as the rotation axis. When the grain boundary length L _T is set, the twin ratio defined by L _T / L × 100 is in the range of 35% to 65%.

Here, the twin ratio described above is calculated as follows. The structure is observed with an EBSD device, the orientation difference between adjacent crystal grains is measured using analysis software, and the grain boundary whose orientation difference is in the range of 5 ° to 180 ° is extracted. FIG. 2A is a diagram showing the grain boundary extraction result, and the black line shows the grain boundary. The length of the grain boundary thus extracted (black line in FIG. 2A) is measured, and the total grain boundary length L is calculated.
Next, a grain boundary which is an orientation difference in which three lattice points are confirmed when rotating with the (111) plane and the (110) plane of the face-centered cubic crystal as a rotation axis is extracted as a twin grain boundary. . FIG. 2B is a diagram showing the results of twin grain boundary extraction, and the black line shows twin grain boundaries. Thus the length of the extracted twin boundaries (black line in FIG. 2 (b)) was measured to calculate the twin boundaries length L _T.
Then, from the total grain boundary length L and twin boundaries length L _T which is calculated as described above, twinning ratio defined by L T _{/ L} × 100 is calculated.

  Further, in the Cu—Ni alloy sputtering target according to the present embodiment, the average crystal grain size is in the range of 5 μm to 100 μm.

  The reason why the twin ratio, the average crystal grain size, and the component composition are defined as described above in the Cu—Ni alloy sputtering target according to this embodiment will be described below.

(Twin ratio)
In the Cu—Ni alloy sputtering target, by reducing the crystal grain size, the difference in the sputtering rate is leveled, the sputtering rate is stabilized over the entire sputtering surface, and uniform film formation becomes possible. However, making the crystal grain size finer than necessary leads to an increase in manufacturing cost and is difficult to realize industrially.
Here, when the twin ratio is high in the Cu—Ni alloy sputtering target, the sputtering rate is stabilized over the entire sputtering surface even if the crystal grain size is the same. Therefore, uniform film formation is possible without making the crystal grain size finer than necessary.

In the Cu—Ni alloy sputtering target, when the twin ratio is less than 35%, the sputtering rate may not be stabilized over the entire sputtering surface. On the other hand, if the twin ratio exceeds 65%, abnormal discharge may occur during sputtering.
For this reason, the twin ratio of the Cu—Ni alloy sputtering target according to the present embodiment is set in the range of 35% to 65%.
In order to further stabilize the sputtering rate over the entire sputtering surface, the lower limit of the twin rate is preferably 40% or more, more preferably 45% or more, while abnormal discharge during sputtering is prevented. In order to further suppress the above, the upper limit of the twin ratio is preferably 60% or less, and more preferably 55% or less.

(Average crystal grain size)
As described above, in the Cu—Ni alloy sputtering target, it is possible to stabilize the sputtering rate over the entire sputtering surface by reducing the crystal grain size. In addition, when the crystal grain size becomes coarse, abnormal discharge may occur during sputtering film formation.
For this reason, in this embodiment, in order to further stabilize the sputtering rate over the entire sputtering surface and suppress the occurrence of abnormal discharge during sputtering film formation, the average crystal grain size is preferably set to 100 μm or less. On the other hand, in order to further suppress the increase in production cost, it is preferable that the average crystal grain size is 5 μm or more.
The lower limit of the average crystal grain size is preferably 10 μm or more, and more preferably 20 μm or more. The upper limit of the average crystal grain size is preferably 80 μm or less, and more preferably 50 μm or less.

(Component composition)
As described above, since Ni and Cu form a complete solid solution, it is possible to control characteristics such as electrical resistance and corrosion resistance of the Cu—Ni alloy film by adjusting the Ni content. For this reason, the Ni content in the Cu—Ni alloy sputtering target is set according to the required characteristics of the formed Cu—Ni alloy film.
Here, when forming a Cu—Ni alloy film sufficiently excellent in corrosion resistance, the Ni content in the Cu—Ni alloy sputtering target is preferably 16 mass% or more. On the other hand, when the electrical resistance of the Cu—Ni alloy film is kept low to ensure conductivity, the Ni content in the Cu—Ni alloy sputtering target is preferably 55 mass% or less, and thus produced. The specific resistance value of the Cu—Ni alloy sputtering target is 5 × 10 ⁻⁴ Ωcm or less.
In addition, when forming a Cu-Ni alloy film having further excellent corrosion resistance, the lower limit of the Ni content in the Cu-Ni alloy sputtering target is preferably 20 mass% or more, and more preferably 25 mass% or more. preferable. On the other hand, when the electrical resistance of the Cu—Ni alloy film is further suppressed, the upper limit of the Ni content in the Cu—Ni alloy sputtering target is preferably 50 mass% or less, and preferably 45 mass% or less.

Next, the manufacturing method of the Cu-Ni alloy sputtering target which is this embodiment is demonstrated.
In this embodiment, a Cu—Ni alloy sputtering target is manufactured by a melt casting method or a powder sintering method. For this reason, below, the melt casting method and the manufacturing method by a powder sintering method are each demonstrated.

  First, the manufacturing method of the Cu-Ni alloy sputtering target by the melt casting method is demonstrated using the flowchart of FIG.

(Melting casting process S01)
Cu raw material and Ni raw material are weighed so as to have a predetermined mixing ratio. Here, it is preferable to use a Cu raw material having a purity of 99.99 mass% or more. Moreover, it is preferable to use a Ni raw material having a purity of 99.9 mass% or more. Specifically, oxygen-free copper is preferably used as the Cu material, and electrolytic Ni is preferably used as the Ni material.

The Cu raw material and Ni raw material weighed as described above are charged into a melting furnace and melted. The Cu raw material and Ni raw material are dissolved in a vacuum or in an inert gas atmosphere (Ar, N _2, etc.). When performed in a vacuum, the degree of vacuum is preferably 10 Pa or less. When performing in an inert gas atmosphere, it is preferable to perform vacuum replacement up to 10 Pa or less and then introduce an inert gas.
In addition, when melt | dissolving in air | atmosphere atmosphere, it is preferable to make a molten metal surface into a reducing atmosphere by using a carbon crucible or covering a molten metal surface with carbon powder etc.

  Then, the obtained molten metal is poured into a mold to obtain a Cu—Ni alloy ingot. The casting method is not particularly limited. In order to reduce the manufacturing cost, it is preferable to apply a continuous casting method, a semi-continuous casting method, or the like.

(Hot rolling process S02)
Next, hot rolling is performed on the obtained Cu—Ni alloy ingot to obtain a hot rolled material.
Here, the twin ratio described above changes depending on the hot rolling temperature and the total processing rate in the hot rolling step S02.

When the hot rolling temperature is less than 600 ° C., the twin ratio may be higher than necessary. On the other hand, when the hot rolling temperature exceeds 1050 ° C., the twin ratio may not be improved.
For this reason, in this embodiment, the hot rolling temperature is set in the range of 600 ° C. or higher and 1050 ° C. or lower.
In addition, it is preferable that the minimum of hot rolling temperature shall be 650 degreeC or more, and it is more preferable to set it as 700 degreeC or more. On the other hand, the upper limit of the hot rolling temperature is preferably 1000 ° C. or less, and more preferably 950 ° C. or less.

Moreover, there exists a possibility that a twin rate cannot be improved as the total processing rate in hot rolling process S02 is less than 70%.
For this reason, in this embodiment, the total processing rate in the hot rolling step S02 is set to 70% or more.
The total processing rate in the hot rolling step S02 is preferably 75% or more, and more preferably 80% or more.

Furthermore, in the hot rolling step S02, it is possible to suppress variation in twin ratio by suppressing the processing rate per pass to be low.
For this reason, in this embodiment, the processing rate per pass in the hot rolling step S02 is set to 15% or less.
The processing rate per pass in the hot rolling step S02 is preferably 14% or less, and more preferably 12% or less.

(Plastic processing step S03)
Next, if necessary, the hot-rolled material is subjected to plastic working such as cold working or leveler processing to obtain a plastic working material. Also in this plastic working step S03, it is preferable to limit the working rate per pass to 15% or less.

(Heat treatment step S04)
Next, heat treatment is performed on the hot-rolled material or the plastic processed material. If necessary, the plastic working step S03 and the heat treatment step S04 may be repeated.
Here, in the final heat treatment step S04, the heat treatment temperature is preferably in the range of 800 ° C. to 1000 ° C., and the holding time at the heat treatment temperature is preferably in the range of 0.5 hour to 2 hours. By performing the final heat treatment under such conditions, the crystal grain size can be reduced.
The lower limit of the heat treatment temperature in the final heat treatment step S04 is preferably 820 ° C. or higher, and more preferably 850 ° C. or higher. Further, the upper limit of the heat treatment temperature in the final heat treatment step S04 is preferably 980 ° C. or less, and more preferably 950 ° C. or less.
Furthermore, the lower limit of the holding time of the final heat treatment step S04 is preferably 0.7 hours or more, and more preferably 0.8 hours or more. Further, the upper limit of the holding time of the final heat treatment step S04 is preferably 1.8 hours or less, and more preferably 1.5 hours or less.

(Machining process S05)
After performing the final heat treatment, a Cu—Ni alloy sputtering target having a predetermined shape and size is obtained by machining.

  Next, the manufacturing method of the Cu-Ni alloy sputtering target by a powder sintering method is demonstrated using the flowchart of FIG.

(Cu-Ni alloy powder forming step S11)
Cu raw material and Ni raw material are weighed so as to have a predetermined mixing ratio. Here, it is preferable to use a Cu raw material having a purity of 99.99 mass% or more. Moreover, it is preferable to use a Ni raw material having a purity of 99.9 mass% or more. Specifically, oxygen-free copper is preferably used as the Cu material, and electrolytic Ni is preferably used as the Ni material.

The Cu raw material and Ni raw material weighed as described above are filled in a crucible and heated to dissolve. Here, as a material for the crucible, ceramic refractories such as alumina, mullite, magnesia, zirconia, or carbon can be used. For example, it is placed in an alumina crucible and set in a gas atomizer. After melt | dissolving Cu raw material and Ni raw material in a vacuum atmosphere, Ar gas is injected while dropping molten metal from a nozzle, and gas atomized powder is produced. After cooling, the obtained gas atomized powder is classified by sieving to obtain a Cu—Ni alloy powder having a predetermined particle size. In the present embodiment, the particle size of the Cu—Ni alloy powder is in the range of 5 μm to 300 μm.
The nozzle hole diameter is preferably in the range of 0.5 mm to 5.0 mm, and the Ar gas injection gas pressure is preferably in the range of 1 MPa to 10 MPa.

(Sintering step S12)
Next, the obtained Cu—Ni alloy powder is pressurized and heated to obtain a sintered body having a predetermined shape.
In addition, about the sintering method in sintering process S12, a hot isostatic pressing method (HIP), a hot press method (HP), etc. are applicable, for example. In this embodiment, a hot isostatic pressing method (HIP) is applied.
Here, the twin ratio described above changes depending on the pressurizing pressure and sintering temperature in the sintering step S12.

If the pressure applied in the sintering step S12 is less than 50 MPa, the twin ratio may not be improved. On the other hand, when the pressurizing pressure in the sintering step S12 exceeds 150 MPa, the twin ratio may be higher than necessary.
For this reason, in this embodiment, the pressurization pressure in sintering process S12 is set in the range of 50 MPa or more and 150 MPa or less.
In addition, it is preferable that the minimum of the pressurization pressure in sintering process S12 shall be 65 Mpa or more, and it is more preferable to set it as 80 Mpa or more. On the other hand, the upper limit of the pressure applied in the sintering step S12 is preferably 135 MPa or less, and more preferably 120 MPa or less.

Moreover, when the sintering temperature in sintering process S12 is less than 800 degreeC, there exists a possibility that a twin ratio cannot be improved. On the other hand, when the sintering temperature in the sintering step S12 exceeds 1200 ° C., the twin ratio may be higher than necessary.
For this reason, in this embodiment, the sintering temperature in sintering process S12 is set in the range of 800 degreeC or more and 1200 degrees C or less.
In addition, it is preferable that the minimum of the sintering temperature in sintering process S12 shall be 850 degreeC or more, and it is more preferable to set it as 900 degreeC or more. On the other hand, the upper limit of the sintering temperature in the sintering step S12 is preferably 1150 ° C. or less, and more preferably 1100 ° C. or less.

  The holding time at the sintering temperature in the sintering step S12 is preferably in the range of 1 hour to 6 hours.

(Machining process S13)
A Cu—Ni alloy sputtering target having a predetermined shape and size is obtained by performing machining on the sintered body obtained in the sintering step S12.

  According to the Cu—Ni alloy sputtering target of the present embodiment configured as described above, since the twin rate is 35% or more, the variation in the sputtering rate on the sputtering surface is reduced, and a uniform film is formed. A Cu—Ni alloy film having a thickness and composition can be formed. On the other hand, since the twin ratio is 65% or less, the occurrence of abnormal discharge during sputtering can be suppressed, and the Cu—Ni alloy film can be stably formed.

  Furthermore, in the Cu—Ni alloy sputtering target according to this embodiment, when the Ni content is 16 mass% or more, a Cu—Ni alloy film having excellent corrosion resistance can be formed. In addition, when the Ni content is 55 mass% or less, a Cu—Ni alloy film with low electrical resistance can be formed. Therefore, it is possible to form a Cu—Ni alloy film particularly suitable for applications that require corrosion resistance and conductivity.

  In addition, in the Cu—Ni alloy sputtering target according to the present embodiment, when the average crystal grain size is 100 μm or less, the sputtering rate can be further stabilized over the entire sputtering surface, and abnormal discharge occurs during sputtering film formation. Can be further suppressed. On the other hand, when the average crystal grain size is 5 μm or more, an increase in manufacturing cost can be suppressed.

Furthermore, in this embodiment, when manufacturing a Cu-Ni alloy sputtering target by melt casting, the hot rolling temperature in the hot rolling step S02 is in the range of 600 ° C to 1050 ° C, and the total processing rate is 70. % Or more, the above-mentioned twin ratio can be made 35% to 65%.
In the final heat treatment step S04, the heat treatment temperature is in the range of 800 ° C. to 1000 ° C., and the holding time at the heat treatment temperature is in the range of 0.5 hours to 2 hours, so the average crystal grain size is 100 μm. It can be as follows.
Furthermore, since the working rate per pass is limited to 15% or less in the hot rolling step S02 and the plastic working step S03, variation in twin ratio can be suppressed.

  Moreover, in this embodiment, when manufacturing a Cu-Ni alloy sputtering target by a powder sintering method, the pressurization pressure in sintering process S12 shall be in the range of 50 Mpa or more and 150 Mpa or less, and sintering in sintering process S12 Since the temperature is in the range of 800 ° C. or more and 1200 ° C. or less, the above-described twin rate can be made 35% or more and 65% or less.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, in the present embodiment, the melt casting method shown in FIG. 3 and the powder sintering method shown in FIG. 4 have been described as examples of the method for producing a Cu—Ni alloy sputtering target, but the present invention is limited to this. There is no particular limitation on the manufacturing method as long as the twin rate is in the range of 35% to 65%.

  Below, the result of the evaluation test evaluated about the Cu-Ni alloy sputtering target of this invention mentioned above is demonstrated.

First, Cu-Ni alloy sputtering targets of Invention Examples 1 to 10 and Comparative Examples 1 and 2 were produced by a melt casting method as follows.
Oxygen-free copper having a purity of 99.99 mass% was prepared as a Cu raw material, and electrolytic Ni having a purity of 99.9% or more was prepared as a Ni raw material. This was weighed so as to have the composition shown in Table 1.
The weighed Cu raw material and Ni raw material were charged into a vacuum melting furnace and melted under the condition of a vacuum degree of 10 Pa. The obtained molten metal was cast into a mold to prepare a Cu—Ni alloy ingot.
Next, this Cu—Ni alloy ingot was subjected to hot rolling under the conditions shown in Table 1 and a final heat treatment.
The obtained plate material was machined to obtain a Cu—Ni alloy sputtering target having a width of 150 mm × a length of 500 mm × a thickness of 15 mm.

In addition, Cu-Ni alloy sputtering targets of Invention Examples 11 to 17 and Comparative Examples 11 and 12 were produced by a powder sintering method as follows.
Prepare oxygen free copper with a purity of 99.99 mass% as a Cu raw material, and electrolytic Ni with a purity of 99.9% or more as a Ni raw material, put this in an alumina crucible and set it in a gas atomizer, and an injection temperature of 1550 ° C. By performing atomization under conditions of a jet gas pressure of 5 MPa and a nozzle diameter of 1.5 mm, Cu—Ni alloy powders having the compositions and particle sizes shown in Table 2 were obtained.
The obtained Cu—Ni alloy powder was pressed and heated by the HIP method under the conditions shown in Table 2 to obtain a sintered body.
The obtained sintered body was machined to obtain a Cu—Ni alloy sputtering target having a width of 150 mm × a length of 500 mm × a thickness of 15 mm.

  About the Cu-Ni alloy sputtering target obtained as described above, the component composition, twin ratio, average crystal grain size, abnormal discharge, and film uniformity (film thickness, composition) were evaluated as follows. The evaluation results are shown in Tables 3 and 4.

(Component composition)
A measurement sample was collected from the obtained Cu—Ni alloy sputtering target, and the Ni content was measured using an XRF apparatus (ZSX Primus II manufactured by Rigaku Corporation). About Cu and other components, it described as a remainder.

(Twin ratio)
The sputtering surface of the obtained Cu—Ni alloy sputtering target is the observation surface, the structure is observed using an EBSD device (TSL Solutions OIM Data Collection 5), and the orientation difference between adjacent crystal grains is determined using analysis software. Measured, grain boundaries whose orientation difference was in the range of 5 ° to 180 ° were extracted, and the total grain boundary length L was calculated.
In addition, a grain boundary that is an orientation difference in which three lattice points are confirmed when rotating with the (111) plane and the (110) plane of a face-centered cubic crystal as a rotation axis is extracted as a twin grain boundary, to calculate the twin boundaries length L _T.
Then, from the total grain boundary length L and twin boundaries length L _T which is calculated as described above, it was calculated twinning ratio defined by L T _{/ L} × 100.

  In addition, about twin ratio, as shown in FIG. 5, in the sputter | spatter surface of a Cu-Ni alloy sputtering target, the intersection (1) where a diagonal cross | intersects, and the corner | angular part (2), (3) on each diagonal, Measure twin ratios at 5 points (4) and (5), and display the average value of twin ratios measured at 5 points and the difference between the maximum and minimum values as variations in Tables 3 and 4. did. The corners (2), (3), (4), and (5) were within the range of 10% or less of the total diagonal length from the corners toward the inside.

(Average crystal grain size)
A measurement sample was taken from the obtained Cu—Ni alloy sputtering target, the sputtered surface was polished, the microstructure was observed with an optical microscope, the crystal grain size was measured by JIS H 0501: 1986 (cutting method), and the average was measured. The crystal grain size was calculated.

(Abnormal discharge)
A Cu—Ni alloy sputtering target was soldered to a backing plate made of oxygen-free copper, and this was mounted on a magnetron DC sputtering apparatus.
Next, film formation by a sputtering method was performed continuously for 60 minutes under the following sputtering conditions. During the sputtering film formation, the number of occurrences of abnormal discharge was counted using an arc counter attached to the power source of the DC sputtering apparatus.
Ultimate vacuum: 5 × 10 ⁻⁵ Pa
Ar gas pressure: 0.3 Pa
Sputter output: DC 1000W

(Membrane uniformity)
The uniformity of the Cu—Ni alloy film formed using the Cu—Ni alloy sputtering target of the present invention example and the comparative example was evaluated by the film thickness and the composition.

The film thickness was evaluated as follows.
A Cu—Ni alloy sputtering target was soldered to a backing plate made of oxygen-free copper, and this was mounted on a magnetron DC sputtering apparatus. A 100 mm square glass substrate was prepared, and sputtering film formation was performed on the surface of the glass substrate with a target film thickness of 100 nm under the following conditions.
Distance between target and substrate: 60mm
Ultimate vacuum: 5 × 10 ⁻⁵ Pa
Ar gas pressure: 0.3 Pa
Sputter output: DC 1000W

  About the formed Cu-Ni alloy film, as shown in FIG. 6, the intersection (1) where the diagonal lines intersect and the corners (2), (3), (4), (5) on each diagonal line At five points, each film thickness was measured using a level difference measuring device. The difference between the maximum value and the minimum value of the measured film thickness is shown in Tables 3 and 4 as “film thickness difference”. The corners (2), (3), (4), and (5) were within the range of 10% or less of the total diagonal length from the corners toward the inside.

The composition was evaluated as follows.
A Cu—Ni alloy sputtering target was soldered to a backing plate made of oxygen-free copper, and this was mounted on a magnetron DC sputtering apparatus. A 100 mm square glass substrate was prepared, and sputter deposition was performed three times on the surface of the glass substrate with a target film thickness of 300 nm under the following conditions.
Ultimate vacuum: 5 × 10 ⁻⁵ Pa
Ar gas pressure: 0.3 Pa
Sputter output: DC 1000W

The Cu-Ni alloy film thus formed was measured for Cu and Ni concentrations with an XRF apparatus (ZSX Primus II manufactured by Rigaku Corporation), and the Ni concentration was normalized by the following formula. The Cu and Ni concentrations are calculated from the detected intensities of Cu and Ni using a calibration curve.
Ni normalized concentration = Ni concentration / (Ni concentration + Cu concentration) × 100
This is performed every three film formations, and the difference between the maximum value and the minimum value of the Ni normalized concentration is shown in Tables 3 and 4 as “composition difference”.

In the comparative casting method in which the total processing rate in the hot rolling process was 60% in the melt casting method, the twinning ratio was as low as 30%. For this reason, the film thickness difference and the composition difference are large, and a uniform film cannot be formed.
In the comparative casting method in which the hot rolling temperature in the hot rolling process was 400 ° C. in the melt casting method, the twinning ratio was as high as 70%. The average crystal grain size was 120 μm. For this reason, the film thickness difference is large and a uniform film cannot be formed. In addition, the number of abnormal discharges was relatively large.

In the powder sintering method, in Comparative Example 11 in which the pressure applied in the sintering step was 10 MPa, the twinning ratio was as low as 31%. For this reason, the film thickness difference and the composition difference are large, and a uniform film cannot be formed.
In the powder sintering method, in Comparative Example 12 in which the pressure applied in the sintering process was 200 MPa, the twinning ratio was as high as 69%. For this reason, the film thickness difference is large and a uniform film cannot be formed.

  On the other hand, according to Invention Examples 1 to 10 manufactured by the melt casting method and Invention Examples 11 to 17 manufactured by the powder sintering method, the twin ratio is 35% or more and 65% or less. The film thickness was within the range, the film thickness difference and the composition difference were relatively small, and a uniform film could be formed.

In the inventive examples 1 to 10 manufactured by the melt casting method, the inventive examples 1 to 4 and 6 to 10 in which the processing rate of one pass is 15%, the processing rate of one pass is set to 20%. Compared to Example 5 of the present invention, variation in twin ratio was suppressed.
In addition, Examples 1 to 6 and 8 to 10 of the present invention having a final heat treatment temperature of 1000 ° C. or lower can reduce the average crystal grain size compared to Example 7 of the present invention having a final heat treatment temperature of 1100 ° C. became.

  From the above, according to the example of the present invention, it is possible to provide a Cu—Ni alloy sputtering target capable of stably forming a Cu—Ni alloy film having a uniform film thickness and composition. confirmed.

Claims (3)

A Cu-Ni alloy sputtering target containing Ni, the balance being Cu and inevitable impurities,
The length of a grain boundary formed between crystal grains in which the orientation difference between adjacent crystal grains is in the range of 5 ° to 180 ° is the total grain boundary length L, and the (111) plane of the face-centered cubic crystal and (110) when the respective grid point the length of the grain boundary is a misorientation is confirmed three when rotating the plane as the rotation axis and the twin boundaries length L _T, L _{T /} L A Cu—Ni alloy sputtering target, wherein the twin ratio defined by × 100 is in the range of 35% to 65%.   The Cu-Ni alloy sputtering target according to claim 1, wherein the Ni content is in the range of 16 mass% or more and 55 mass% or less, and the balance is composed of Cu and inevitable impurities.   The Cu-Ni alloy sputtering target according to claim 1 or 2, wherein an average crystal grain size is in a range of 5 µm to 100 µm.