JP2017172039A - Sputtering target - Google Patents

Abstract

A sputtering target capable of performing DC (direct current) sputtering and capable of forming a uniform copper oxide film is provided. The volume ratio of the copper oxide phase is more than 80 vol% and not more than 90 vol%, and the copper oxide phase has a volume ratio of not more than 90 vol%. The variation is set to 50% or less, and the particle size of the metallic copper phase in the target structure is set in a range of 10 μm to 200 μm. Further, it preferably has the properties of a p-type semiconductor. [Selection diagram] None

Description

  The present invention relates to a sputtering target used when forming a copper oxide film.

Generally, as a conductive film used for a touch sensor or the like, one having a transparent conductor layer formed on both surfaces of the film and a metal layer formed on the surface of each transparent conductor layer is known. .
Here, in the above-mentioned conductive film, when wound in a roll shape, adjacent conductive films are in close contact with each other, and when the close conductive film is peeled off, the transparent conductor layer is scratched. There was a problem.

  Therefore, Patent Document 1 proposes a film in which an inorganic nanocoating layer is formed on a film substrate. In this film, the adhesion between adjacent films can be suppressed by the inorganic nanocoating layer. A copper oxide film can be applied as the inorganic nanocoating layer.

Examples of a method for forming a copper oxide film on the surface of a substrate such as a film include sputtering using a copper oxide target, and sputtering in the presence of oxygen gas using an oxygen-free copper target (reactivity A method of performing sputtering) is disclosed.
For example, Patent Document 2 proposes an oxygen-containing copper target for forming an oxygen-containing copper film.
Patent Document 3 discloses a sputtering target made of a Cu / Cu ₂ O composite alloy.

Special table 2014-529516 JP 2008-280545 A Japanese Patent Laid-Open No. 2001-210441

By the way, when sputtering is performed in the presence of oxygen gas using an oxygen-free copper target, the reaction between copper and oxygen cannot be sufficiently controlled, and it is difficult to form a uniform copper oxide film. Met.
When a copper oxide target is used, the resistance of the target itself is very high and DC (direct current) sputtering is difficult, so RF (high frequency) sputtering is usually performed. This RF (high frequency) sputtering has a problem that the film forming speed is low and the productivity is lowered.

Furthermore, in the oxygen-containing copper target described in Patent Document 2, since the oxygen content is small, the formed oxygen-containing copper film has the same characteristics as the metal copper film, and as a copper oxide film The characteristics of were insufficient.
Patent Document 3 describes that processing becomes difficult when the compounding ratio of Cu ₂ O exceeds 80 vol%. Furthermore, it is described that when the compounding ratio of Cu ₂ O increases, the resistance value of the formed wiring film increases. Therefore, in Patent Document 3, limiting the blending ratio of Cu ₂ O below 80 vol%.
As described in Patent Document 3, when the Cu ₂ O compounding ratio is 80 vol% or less and the content of metal Cu is high, the metal Cu phase is present in a network and the conductivity is low. It is secured. In the sputtering target having such a configuration, a copper oxide phase having a lower conductivity than that of metal Cu may cause abnormal discharge, and there is a possibility that sputtering cannot be stably performed.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a sputtering target capable of DC sputtering and capable of forming a uniform copper oxide film.

  In order to solve the above problems, the sputtering target of the present invention has a metallic copper phase and a copper oxide phase, and the volume fraction of the copper oxide phase is in the range of more than 80 vol% and 90 vol% or less. The variation of the resistance value on the target sputtering surface with respect to the average value is 50% or less, and the average particle size of the metallic copper phase in the target structure is in the range of 10 μm to 200 μm.

According to the sputtering target of the present invention, since the volume fraction of the copper oxide phase exceeds 80 vol%, the copper oxide phase is sufficiently present, and the copper oxide film can be obtained without performing sputtering in the presence of oxygen gas. Can be formed.
Moreover, since the volume ratio of the copper oxide phase is in the range of 90 vol% or less, and the particle size of the metal copper phase in the target structure is in the range of 10 μm or more and 200 μm or less, a relatively fine metal copper phase Are uniformly dispersed. The variation of the resistance value on the target sputtering surface with respect to the average value is 50% or less, and the variation in the resistance value of the target sputtering surface is small, so that the conductivity of the entire target is sufficiently ensured. Therefore, a copper oxide film can be stably formed by DC sputtering.

Here, in the sputtering target of this invention, it is preferable that the target has the property of a p-type semiconductor as a whole.
In this case, the metallic copper phase is dispersed in an island shape, and the copper oxide phase existing between these metallic copper phases contributes to the conductivity of the target as a p-type semiconductor, so that the target as a whole has the properties of a p-type semiconductor. Therefore, it is considered that conductivity can be ensured. This makes it possible to form a copper oxide film by DC sputtering without causing the copper oxide phase to cause abnormal discharge.
On the other hand, when the metal Cu phase is present in a network form and conductivity is ensured, the target as a whole does not have semiconductor properties. In the sputtering target having such a configuration, a copper oxide phase having a lower conductivity than metal Cu may cause abnormal discharge, and thus there is a possibility that stable sputtering cannot be performed.

Moreover, in the sputtering target of this invention, it is preferable that resistance value is 10 ohm * cm or less.
In this case, since the resistance value of the target is sufficiently low, DC sputtering can be reliably performed.

Furthermore, in the sputtering target of the present invention, as a result of X-ray diffraction analysis, the ratio I1 / I2 between the diffraction intensity I1 of CuO and the diffraction intensity I2 of Cu ₂ O is preferably 0.15 or less.
In this case, the existing ratio of CuO is small in the copper oxide phase and the existing ratio of Cu ₂ O is high. Here, since CuO reacts with metallic copper to produce Cu ₂ O, when the abundance ratio of CuO is high, metallic copper and CuO are not sufficiently reacted. For this reason, Cu ₂ O is uniformly dispersed by setting the abundance ratio of CuO in the copper oxide phase to 0.15 or less, and variation in resistance value in the target can be suppressed.

In the sputtering target of the present invention, as a result of X-ray photoelectron spectroscopy, the ratio IP1 / IP2 between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O is 0.03 or more and 0.4 or less. It is preferable to be within the range.
In this case, the ratio IP1 / IP2 between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O is 0.03 or more, and CuO is present in the copper oxide phase. The strength is improved and the occurrence of cracks during production can be suppressed. On the other hand, since IP1 / IP2 is 0.4 or less, the abundance ratio of CuO in the copper oxide phase is reduced, and variation in resistance value in the target can be suppressed.

Further, in the sputtering target of the present invention, the density is preferably in the range of 5.5 g / cm ³ or more and 7.5 g / cm ³ or less.
In this case, since the density is set to 5.5 g / cm ³ or more, voids existing on the target sputtering surface can be reduced, and occurrence of abnormal discharge during sputtering can be suppressed. Further, since the density is 7.5 g / cm ³ or less, the workability is improved and the sputtering target can be easily formed.

  According to the present invention, a sputtering target capable of DC sputtering and capable of forming a uniform copper oxide film can be provided.

It is explanatory drawing which shows the measurement position of the resistance value in the target sputtering surface of the sputtering target whose target shape is a flat plate and whose target sputtering surface is circular. It is explanatory drawing which shows the measurement position of the resistance value in the target sputtering surface of the sputtering target whose target shape is a flat plate and whose target sputtering surface is a rectangle. It is explanatory drawing which shows the measurement position of the resistance value in the target sputtering surface of the sputtering target whose target shape is a cylinder and whose target sputtering surface is a cylindrical outer peripheral surface. It is a figure which shows an example of the XRD result in this invention example 2 and the comparative example 1. FIG. It is a figure which shows an example of the XPS result in the example 16 of this invention.

Below, the sputtering target which is one Embodiment of this invention is demonstrated. In addition, the sputtering target which is this embodiment is used when forming a copper oxide film.
The sputtering target which is this embodiment has a metallic copper phase and a copper oxide phase, and the volume ratio of the copper oxide phase exceeds 80 vol% and is within a range of 90 vol% or less. In the present embodiment, the Cu content is in the range of 70 atomic% to 74 atomic%.
The metallic copper phase is dispersed in an island shape in the target, and the average particle size of the metallic copper phase is in the range of 10 μm to 200 μm.
And in the sputtering target which is this embodiment, the dispersion | variation with respect to the average value of the resistance value in a target sputtering surface is 50% or less.

The copper oxide phase is mainly composed of Cu ₂ O, and CuO may partially exist. Here, in the sputtering target of the present embodiment, as a result of X-ray diffraction analysis (XRD), the ratio I1 / I2 between the diffraction intensity I1 of CuO and the diffraction intensity I2 of Cu ₂ O is 0.15 or less. ing.
Furthermore, in the sputtering target of the present embodiment, as a result of X-ray photoelectron spectroscopy (XPS), the ratio IP1 / IP2 between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O is 0.03 or more. It is within the range of 0.4 or less.

And in the sputtering target which is this embodiment, it has the property of a p-type semiconductor as the whole target.
Moreover, the resistance value of the sputtering target which is this embodiment is 10 Ω · cm or less.
Furthermore, in the sputtering target which is this embodiment, the density is in the range of 5.5 g / cm ³ or more and 7.5 g / cm ³ or less.

  Below, the volume ratio of the copper oxide phase in the sputtering target according to the present embodiment, the average particle diameter of the metal copper phase, the variation in resistance value, the diffraction intensity of X-ray diffraction analysis (XRD), and the X-ray photoelectron spectroscopy analysis (XPS) The reason why the peak intensity and density are defined as described above will be described.

(Volume ratio of the copper oxide phase: more than 80 vol%, 90 vol% or less)
In the sputtering target according to this embodiment, the copper oxide film is formed by DC sputtering, and the abundance ratio of the metal copper phase and the copper oxide phase is particularly important.
Here, when the volume ratio of the copper oxide phase is less than 80 vol%, a relatively large amount of metallic copper is present in the formed copper oxide film, and a copper oxide film having characteristics as copper oxide can be formed. There is a risk of disappearing.
On the other hand, when the volume ratio of the copper oxide phase exceeds 90 vol%, the resistance value of the entire target increases, and there is a possibility that DC sputtering cannot be performed. In the present embodiment, the metal copper phase is dispersed in islands, and the copper oxide phase existing between them acts as a p-type semiconductor that reacts with the metal copper phase and degenerates. If it is not dispersed, the resistance value of the entire target will increase.
For this reason, in this embodiment, the volume ratio of the copper oxide phase is set in the range of more than 80 vol% and 90 vol% or less.
In order to reliably form a copper oxide film having excellent characteristics, the volume ratio of the copper oxide phase is preferably 85 vol% or more. On the other hand, in order to further suppress the resistance value of the sputtering target, the volume ratio of the copper oxide phase is preferably 85 vol% or less. That is, it is preferable to appropriately adjust the volume ratio of the copper oxide phase in consideration of required characteristics or resistance values within the range of 80 vol% and 90 vol% or less of the volume ratio of the copper oxide phase.

(Average particle size of metallic copper phase: 10 μm or more and 200 μm or less)
In order to form a copper oxide film by DC sputtering, it is necessary to ensure conductivity throughout the target.
In this embodiment, since the average particle diameter of the metallic copper phase is relatively fine as 200 μm or less, the metallic copper phase is relatively uniformly dispersed. Here, in the present embodiment, as described above, the metal copper phase is dispersed in the form of islands, and the copper oxide phase existing between these acts as a p-type semiconductor. By being uniformly dispersed, conductivity can be ensured over the entire target, and DC sputtering can be performed stably.
Moreover, when manufacturing the sputtering target which is this embodiment, metal copper powder will be used, but by defining the average particle size of the metal copper phase to 10 μm or more, the particle size of the metal copper powder is excessively fine. Therefore, oxidation of the metal copper powder can be suppressed.
From the above, in this embodiment, the average particle diameter of the metallic copper phase is set within the range of 10 μm or more and 200 μm or less. In order to secure conductivity over the entire target and perform DC sputtering more stably, the upper limit of the average particle diameter of the metallic copper phase is preferably 150 μm or less, and more preferably 100 μm or less. Moreover, in order to suppress the oxidation of the raw metal copper powder with certainty, the lower limit of the average particle diameter of the metal copper phase is preferably 20 μm or more, and more preferably 30 μm or more.

(Variation with respect to the average resistance value on the target sputtering surface: 50% or less)
In the sputtering target according to the present embodiment, conductivity is ensured by dispersing the metal copper phase, and DC sputtering is possible. Here, when the variation with respect to the average value of the resistance value on the target sputtering surface exceeds 50%, the metal copper phase is not uniformly dispersed, and there is a possibility that the DC sputtering cannot be performed stably. In addition, abnormal discharge may occur during sputtering.
For this reason, in this embodiment, the variation with respect to the average resistance value on the target sputtering surface is set to 50% or less. In order to make it possible to carry out DC sputtering reliably by uniformly dispersing the copper metal phase, it is preferable to set the variation of the resistance value on the target sputtering surface to 40% or less, preferably 30% or less. More preferably.

Here, in the present embodiment, when the shape of the sputtering target is a flat plate and the target sputtering surface is circular, as shown in FIG. 1, it passes through the center (1) of the circle and the center of the circle. In addition, the resistance value is measured at five points (2), (3), (4), and (5) on the outer peripheral portions (2), (3), (4), and (5) on two straight lines orthogonal to each other. The variation with respect to is calculated | required.
When the shape of the sputtering target is a flat plate and the target sputtering surface is rectangular, as shown in FIG. 2, the intersection (1) where the diagonal lines intersect and the corners (2), (3) on each diagonal line ), (4), and (5), the resistance value is measured, and the variation with respect to the average value of the resistance value on the target sputtering surface is obtained by the following equation.
Further, when the shape of the sputtering target is a cylinder and the target sputtering surface is a cylindrical outer peripheral surface, as shown in FIG. 3, (1), (2) at intervals of 90 ° from the half point in the axis O direction to the outer peripheral direction. ), (3), and (4), the resistance value is measured, and the variation with respect to the average value of the resistance value on the target sputtering surface is obtained by the following equation.
(Variation)% = standard deviation / average value x 100

(Resistance value: 10Ω · cm or less)
In order to perform DC sputtering, in the sputtering target of this embodiment, the resistance value is preferably 10 Ω · cm or less, and more preferably 1 Ω · cm or less.
In addition, let the resistance value of the sputtering target in this embodiment be an average value of the measured value of the above-mentioned 5 points | pieces.

(Ratio of the diffraction intensity of CuO I1 and Cu ₂ O diffraction intensity I2 I1 / I2: 0.15 or less)
When manufacturing a sputtering target by sintering, CuO and metallic copper react to produce Cu ₂ O. Here, when the ratio I1 / I2 of the diffraction intensity I1 and Cu ₂ O diffraction intensity I2 of CuO is 0.15 or less, low existence ratio of CuO, metallic copper and the CuO is fully reacted Will be. For this reason, the dispersion | variation in resistance value within a target is suppressed and generation | occurrence | production of abnormal discharge is suppressed.
From the above, in this embodiment, the ratio I1 / I2 between the diffraction intensity I1 of CuO and the diffraction intensity I2 of Cu ₂ O is set to 0.15 or less. In order to suppress the variation of the resistance value and suppress the occurrence of abnormal discharge, the ratio I1 / I2 of the CuO diffraction intensity I1 and the Cu ₂ O diffraction intensity I2 should be 0.1 or less. Is preferable, and it is more preferable to set it as 0.05 or less.

(Ratio IP1 / IP2: 0.03 or more and 0.4 or less of peak intensity IP1 of CuO and peak intensity IP2 of Cu and Cu ₂ O in X-ray photoelectron spectroscopy (XPS))
When the sputtering target is manufactured by sintering as described above, CuO and metallic copper react to produce Cu ₂ O. Here, when the ratio IP1 / IP between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O in X-ray photoelectron spectroscopy (XPS) is 0.03 or more, CuO is present in the copper oxide phase. As a result, the strength of the sintered body is improved, and the occurrence of cracks during production can be suppressed. On the other hand, when IP1 / IP is 0.4 or less, the metal copper and CuO are sufficiently reacted, so that variation in resistance value is suppressed in the target and occurrence of abnormal discharge is suppressed. The
From the above, in this embodiment, the ratio IP1 / IP2 between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O in the X-ray photoelectron spectroscopy (XPS) is 0.03 or more and 0.4 or less. It is set within the range. In order to improve the strength of the sintered body and reliably suppress cracking during production, the lower limit of the above IP1 / IP2 is preferably 0.05 or more, and more preferably 0.1 or more. Further preferred. Further, in order to reliably suppress the variation in resistance value and suppress the occurrence of abnormal discharge, the upper limit of the above-mentioned IP1 / IP2 is preferably set to 0.3 or less, and more preferably to 0.2 or less. preferable.
As shown in FIG. 5, since it is difficult to separate the Cu peak and the Cu ₂ O peak in X-ray photoelectron spectroscopy (XPS), the peak intensities IP2 of Cu and Cu ₂ O are used. The CuO abundance ratio is specified.

(Density: 5.5 g / cm ³ or more and 7.5 g / cm ³ or less)
When the density of the sputtering target is 5.5 g / cm ³ or more, voids existing on the target sputtering surface can be reduced, and occurrence of abnormal discharge during sputtering can be suppressed. On the other hand, if the density of the sputtering target is 7.5 g / cm ³ or less, the workability is improved and the sputtering target is easily formed.
Therefore, in this embodiment, defines the density of the sputtering target in the range of 5.5 g / cm ³ or more 7.5 g / cm ³ or less.
In order to reliably suppress abnormal discharge during sputtering, the lower limit of the density of the sputtering target is preferably 6.0 g / cm ³ or more, and more preferably 6.2 g / cm ³ or more. Further, in order to reliably ensure the workability of the sputtering target, it is preferable that the upper limit of the density of the sputtering target and 7.0 g / cm ³ or less, and more preferably set to 6.8 g / cm ³ or less.

(Manufacturing method of sputtering target)
Next, the manufacturing method of the sputtering target which is this embodiment is demonstrated.
First, copper metal powder and copper oxide powder are prepared. Here, it is preferable to use a metal copper powder having a purity of 4N or more. Moreover, it becomes possible to control the average particle diameter of the metallic copper phase in the sputtering target by adjusting the particle diameter of the metallic copper powder. Specifically, it is preferable that the average particle diameter of the metallic copper powder is in the range of 10 μm to 200 μm.
As the copper oxide powder, CuO powder, Cu ₂ O powder, and it is possible to use these mixed powder. It is preferable to use CuO powder and Cu ₂ O powder having a purity of 2N or more. The average particle size of the CuO powder and Cu ₂ O powder is preferably in the range of 1 μm to 30 μm.

  Next, the weighed metal copper powder and copper oxide powder are mixed by a mixing device such as a ball mill, a Henschel mixer, a rocking mixer, etc. to obtain a raw material powder. At this time, in order to prevent oxidation of the copper metal powder, the atmosphere in the mixing apparatus is preferably an inert gas atmosphere such as Ar.

Next, the raw material powder described above is used to sinter by hot pressing or the like to obtain a sintered body. The sputtering target which is this embodiment is manufactured by machining the obtained sintered compact. The sintering temperature is preferably 600 ° C. or more and 900 ° C. or less, the holding time is preferably 30 min or more and 600 min or less, and the pressing pressure is preferably 10 MPa or more and 50 MPa or less.
Here, when CuO powder is used as the copper oxide powder, the reaction between CuO and Cu can be promoted by setting the sintering temperature to 720 ° C. or higher, and the CuO existing ratio in the sputtering target can be increased. It becomes possible to reduce.

  In the sputtering target according to the present embodiment configured as described above, since the volume fraction of the copper oxide phase exceeds 80 vol%, the copper oxide phase is sufficiently present and sputtered in the presence of oxygen gas. Even if it does not perform, a copper oxide film | membrane can be formed into a film. Moreover, since the volume ratio of the copper oxide phase is in the range of 90 vol% or less and the particle size of the metal copper phase in the target structure is in the range of 10 μm or more and 200 μm or less, the metal copper phase is relatively uniform. Thus, the conductivity of the entire target is ensured. Thereby, a copper oxide film can be formed by DC sputtering.

  Moreover, in the sputtering target which is this embodiment, since the average particle diameter of the metallic copper phase is 200 μm or less, the metallic copper phase is finely dispersed in the target, and the entire target is conductive. Can be secured. Thereby, DC sputtering can be performed stably. On the other hand, since the average particle diameter of the metallic copper phase is 10 μm or more, it is not necessary to excessively reduce the particle diameter of the metallic copper powder at the time of target production, and the oxidation of the metallic copper powder can be suppressed. Good ligation can be performed.

  Furthermore, in this embodiment, since the variation with respect to the average value of the specific resistance value on the target sputtering surface is 50% or less, sufficient conductivity is ensured as a whole target, which is stabilized by DC sputtering. Thus, a copper oxide film can be formed.

  In the present embodiment, the metal copper phase is dispersed in an island shape, and the copper oxide phase existing between these metal copper phases reacts with the metal copper phase to act as a degenerate p-type semiconductor, The target as a whole has the properties of a p-type semiconductor, and it is considered that conductivity is ensured. Therefore, a copper oxide film can be formed by DC sputtering.

Furthermore, in this embodiment, since the resistance value of the sputtering target is 10 Ω · cm or less, DC sputtering can be reliably performed.
In the present embodiment, as a result of X-ray diffraction analysis (XRD), the ratio I1 / I2 between the diffraction intensity I1 of CuO and the diffraction intensity I2 of Cu ₂ O is 0.15 or less. Cu ₂ O is uniformly dispersed as a copper phase, and variation in resistance value in the target can be suppressed.

Furthermore, in the present embodiment, as a result of X-ray photoelectron spectroscopy, the ratio IP1 / IP2 between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O is 0.03 or more. The strength of the body is improved and the occurrence of cracks during production can be suppressed. Moreover, since IP1 / IP2 is 0.4 or less, the abundance ratio of CuO is reduced in the copper oxide phase, and variation in resistance value in the target can be suppressed.

Furthermore, in the sputtering target which is this embodiment, since the density is 5.5 g / cm ³ or more, the occurrence of abnormal discharge during sputtering can be suppressed. On the other hand, since the density is 7.5 g / cm ³ or less, workability is ensured, and this sputtering target can be molded well.

  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.

  Below, the result of the confirmation experiment performed in order to confirm the effectiveness of this invention is demonstrated.

(Sputtering target)
As raw material powder, metallic copper powder (purity: 99.9 mass% or more, average particle diameter is described in Table 1), CuO powder (purity: 99 mass% or more, average particle diameter 5 μm), Cu ₂ O powder (purity: 99 mass%) Thus, an average particle size of 3 μm was prepared.
These raw materials were weighed so as to have the molar ratios shown in Table 1, and placed in a container of a ball mill apparatus having an Ar gas atmosphere. The weighed raw materials and zirconia balls (diameter: 3 times the weight of the raw materials). 5 mm) and mixed for 3 hours.
After the obtained raw material powder is sieved, it is filled into a hot press flat plate and a cylindrical mold, and the flat plate shape is cylindrical for 3 hours at a sintering temperature shown in Table 1 under a pressure of 200 kgf / cm ^2. The shape was held for 5 hours.
The obtained sintered body was machined to produce a sputtering target for evaluation (126 mm × 178 mm × 6 mm, cylindrical shape: (φ155 mm−φ135 mm) × 150 mmL). The following items were evaluated. The evaluation results are shown in Tables 1 and 2.

(Volume ratio of the copper oxide phase in the target)
The concentration (atomic%) of copper in the target is measured by a titration method, and the remainder is calculated as oxygen. The volume fraction with copper was calculated on the assumption that the calculated oxygen was present as the total amount of Cu ₂ O. In addition, since it does not consider about a void | hole, the volume ratio here excludes a void | hole.

(Target composition)
The concentration of copper in the target was measured by a titration method, and the remainder was calculated as oxygen.

(Membrane composition)
The concentration of copper in the film was measured by a titration method, and the remainder was calculated as oxygen.

(Target density)
The density was calculated from the weight and dimensions.

(Target resistance value)
The resistivity of the sputtering target was measured with a resistance measuring device. If it is a flat plate shape, about five measurement points (1-5) in the target sputtering surface as shown in FIGS. 1 and 2, if it is a cylindrical shape, it is in the target sputtering surface as shown in FIG. The resistivity was measured at the four measurement points (1 to 4). Table 2 shows the measured average values of the in-plane resistivity. In this measurement, a resistivity (Ω · cm) was measured by a four-probe method using a low resistivity meter (Loresta-GP) manufactured by Mitsubishi Chemical Corporation as a resistance measuring device. The measurement temperature was 23 ± 5 ° C., and the humidity was 50 ± 20%.
(Variation)% = standard deviation / average value x 100

(Pn determination)
About the sputtering target, PN determination was performed with the PN determination device. If it is a flat plate shape, about one measurement point (1) in the target sputtering surface as shown in FIGS. 1 and 2, if it is a cylindrical shape, 1 in the target sputtering surface as shown in FIG. PN determination was performed for the measurement point at the location (1). The determination results are shown in Table 2. In this measurement, PN determination using a PN determination device (MODEL PN-01) manufactured by NP Corporation was used as the PN determination device, and PN determination was performed using a thermoelectromotive force probe. The measurement temperature was 23 ± 5 ° C., and the humidity was 50 ± 20%.

(Particle size of metallic copper phase)
The size of the metal copper phase particles in the structure of the sputtering target was confirmed from the IQ map obtained by EBSD. In addition, the IQ map observed the cross-sectional range of 500 micrometers x 750 micrometers, and measured the particle size quantitatively.
In addition, EBSD collected the pattern using OIM Data Collection of TSL Solutions, Inc., and calculated the particle size using OIM Analysis 5.31 manufactured by the company.

(X-ray diffraction analysis)
X-ray diffraction analysis (XRD) was performed under the following conditions. The intensity ratio was calculated with the intensity of the 111 plane of CuO as I1 and the intensity of the 200 plane of Cu ₂ O as I2. An example of the analysis result is shown in FIG.
Preparation of sample: The sample was polished with SiC-Paper (grit 180) and used as a measurement sample.
Equipment: Rigaku Electric (RINT-Ultima / PC)
Tube: Cu
Tube voltage: 40 kV
Tube current: 40 mA
Scanning range (2θ): 5 ° -80 °
Slit size: Divergence (DS) 2/3 degree, Scattering (SS) 2/3 degree, Light reception (RS) 0.8mm
Measurement step width: 0.02 degrees at 2θ Scan speed: 2 degrees per minute Sample stage rotation speed: 30 rpm

(X-ray photoelectron spectroscopy)
X-ray photoelectron spectroscopy (XPS) was performed under the following conditions. The measurement surface of the measurement sample was polished with polishing paper # 2000, and analyzed by performing Ar sputtering from the outermost surface. In addition, this measurement was performed 20 minutes after the start of sputtering, and Cu2p3 / 2 spectrum data was used. An example of the analysis result is shown in FIG.
Device: ULVAC-PHI PHI5000 VersaProbeII
X-ray source: Monochromated AlKα 50W
Path energy: 187.85 eV (Survey), 46.95, 58.7 eV (Profile)
Measurement interval: 0.8 eV / step (Survey), 0.1, 0.125 eV / step (Profile)
Photoelectron extraction angle with respect to sample surface: 45 deg
Analysis area: About 200μmφ

(Cracking during manufacturing)
Twenty sputtering targets were prepared under the above-described conditions, and the number of cracks generated at that time was counted.

(Number of abnormal discharges)
About the obtained sputtering target, the frequency | count of abnormal discharge generation | occurrence | production at the time of sputtering was measured in the following procedures.
In the flat sputtering target, a film formation test was performed under the following film formation conditions.
Power supply: DC600W
Total pressure: 0.4Pa
Sputtering gas: Ar = 50 sccm
Target-substrate (TS) distance: 70mm
In addition, a film formation test was performed on the cylindrical sputtering target under the following film formation conditions.
Target size: (φ155mm-φ135mm) × 150mmL (4 divisions)
Power supply: DC2000W
Total pressure: 0.4Pa
Sputtering gas: Ar = 160 sccm
Target-substrate (TS) distance: 60mm
Sputtering was performed for 1 hour under the above film formation conditions, and the number of occurrences of abnormal discharge was automatically measured by an arcing counter attached to the sputtering power supply.

(Membrane resistance)
In this measurement, sheet resistance (Ω / sq) was measured by a four-probe method using a low resistivity meter (Loresta-GP) manufactured by Mitsubishi Chemical Corporation as a resistance measuring device. The measurement temperature was 23 ± 5 ° C., and the humidity was 50 ± 20%.
The sample used for the measurement was produced under the above sputtering conditions. The film was formed on a glass substrate with a target film thickness of 200 nm.

In Comparative Example 1 and Comparative Example 3 in which the volume fraction of the copper oxide phase exceeded 90 vol%, the resistance value was high and DC sputtering could not be performed.
In Comparative Example 2 and Comparative Example 4 in which the volume ratio of the copper oxide phase was 80 vol% or less, the resistance value of the formed copper oxide film was low, and the characteristics as the copper oxide film were insufficient.

In Comparative Example 5 in which the variation with respect to the average resistance value on the target sputtering surface exceeded 50%, the number of abnormal discharges was large, and stable sputtering could not be performed.
In Comparative Example 6 in which the particle size of the metallic copper phase is less than 10 μm, the number of abnormal discharges was large, and stable sputtering could not be performed.
In Comparative Example 7 in which the particle size of the metallic copper phase exceeds 200 μm, the number of abnormal discharges was large, and stable sputtering could not be performed.

On the other hand, according to the example of the present invention, it was confirmed that a resistance value is low, DC sputtering is possible, and a copper oxide film having excellent characteristics can be formed.
Further, as a result of X-ray photoelectron spectroscopic analysis, the ratio IP1 / IP2 between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O was in the range of 0.03 or more and 0.4 or less. In -3, 7, 8, 10-14, 16, 17 it was confirmed that the occurrence of cracks during production was suppressed.

Claims (6)

It has a metal copper phase and a copper oxide phase, and the volume ratio of the copper oxide phase is in the range of more than 80 vol% and 90 vol% or less,
The variation with respect to the average value of the resistance value on the target sputtering surface is 50% or less,
A sputtering target, wherein an average particle diameter of the metallic copper phase in the target structure is in a range of 10 μm or more and 200 μm or less.   The sputtering target according to claim 1, which has a p-type semiconductor property.   The sputtering target according to claim 1, wherein the resistance value is 10 Ω · cm or less. The sputtering target according to any one of claims 1 to 3, the ratio I1 / I2 of the diffraction intensity I1 and Cu ₂ O diffraction intensity I2 of CuO is equal to or more than 0.15. As a result of X-ray photoelectron spectroscopy, the ratio IP1 / IP2 between the peak intensity IP1 of CuO and the peak intensity IP2 of Cu and Cu ₂ O is in the range of 0.03 to 0.4. The sputtering target according to any one of claims 1 to 4. 6. The sputtering target according to claim 1, wherein the density is in a range of 5.5 g / cm ³ or more and 7.5 g / cm ³ or less.

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