阅读说明：本技术 溅射靶材 (Sputtering target material ) 是由 森晓 熊谷训 谷雨 佐藤雄次 于 2019-10-23 设计创作，主要内容包括：本发明提供一种溅射靶材,含有合计5质量ppm以上且50质量ppm以下的范围的选自Ag、As、Pb、Sb、Bi、Cd、Sn、Ni、Fe中的一种或两种以上,剩余部分由Cu及不可避免的杂质构成,当通过电子背散射衍射法进行观察,将不包括双晶而以面积平均计算出的平均晶粒直径设为X1(μm),并将极图的强度的最大值设为X2时,满足式(1)：2500＞19×X1+290×X2,并且通过电子背散射衍射法测定的晶体取向的局部取向差(KAM)为2.0°以下,相对密度为95％以上。(The present invention provides a sputtering target material containing one or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe in a total amount of 5 to 50 mass ppm, the remainder being Cu and unavoidable impurities, wherein when an average crystal grain diameter calculated on an area average without including twins is X1(μm) and a maximum value of intensity of a pole figure is X2 As observed by an electron back scattering diffraction method, formula (1) is satisfied: 2500 > 19 XX 1+290 XX 2, and the crystal orientation measured by electron back scattering diffraction method has a local orientation difference (KAM) of 2.0 DEG or less and a relative density of 95% or more.)

1. A sputtering target material characterized by containing one or more kinds selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni and Fe in a total amount of 5 to 50 mass ppm, the remainder being Cu and unavoidable impurities,

when the sputtering target was observed by electron back scattering diffraction method, the average crystal grain diameter calculated by area average excluding twins was set to X1, and the maximum value of the intensity of the pole figure was set to X2,

satisfies formula (1): 2500 > 19 xX 1+290 xX 2, wherein the average grain diameter is in μm,

and the local orientation difference KAM of the crystal orientation measured by the electron back scattering diffraction method is 2.0 DEG or less,

the relative density of the sputtering target material is more than 95%.

2. The sputtering target according to claim 1,

the average GOS of the differences in crystal orientation between one measurement point and all other measurement points in the same crystal grain measured by the electron back scattering diffraction method is 4 DEG or less.

3. The sputtering target according to claim 1 or 2, wherein the sputtering target contains one or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe in a total amount within a range of 10 mass ppm or more and 50 mass ppm or less.

4. The sputtering target according to any one of claims 1 to 3,

when the sputtering target was observed by electron back scattering diffraction method, the average crystal grain diameter calculated by area average excluding twins was set to X1, and the maximum value of the intensity of the pole figure was set to X2,

satisfies formula (2): 1600 > 11 xx 1+280 xx 2, wherein the average grain diameter is in μm.

5. The sputtering target according to any one of claims 1 to 4,

the difference in local orientation KAM of crystal orientation measured by electron back scattering diffraction method is 1.5 DEG or less.

6. The sputtering target according to any one of claims 1 to 5, which is composed of a sintered body of copper powder.

Technical Field

The present invention relates to a sputtering target used for forming a copper film used as a wiring film or the like in, for example, a semiconductor device, a flat panel display such as a liquid crystal or organic EL panel, a touch panel, or the like.

The present application claims priority based on patent application No. 2019-000733 filed in japanese application at 7.1.2019, and the contents thereof are incorporated herein by reference.

Background

Conventionally, Al has been widely used as a wiring film for a semiconductor device, a flat panel display such as a liquid crystal or organic EL panel, or a touch panel. In recent years, wiring films having a lower resistance than conventional wiring films have been demanded in order to achieve finer wiring films (narrower wiring films) and thinner wiring films.

Therefore, with the miniaturization and thinning of the wiring film, a wiring film made of copper (Cu), which is a material having a lower specific resistance than Al, is provided.

The wiring film is generally formed in a vacuum atmosphere using a sputtering target. Here, when the film is formed using the sputtering target, abnormal discharge (arc discharge) may occur due to foreign matter in the sputtering target, and thus a uniform wiring film may not be formed. Here, the abnormal discharge is a phenomenon in which an abnormally large discharge is rapidly generated by a sudden and rapid flow of a very high current compared to that in the normal sputtering, and when such abnormal discharge is generated, it may cause generation of particles or cause unevenness in the film thickness of the wiring film. Therefore, it is desirable to avoid abnormal discharge during film formation as much as possible.

Therefore, the following patent documents 1 to 7 propose techniques for suppressing generation of abnormal discharge during film formation of a pure copper sputtering target.

Patent document 1 proposes a hot-rolled copper plate made of pure copper having a purity of 99.99 mass% or more, having an average crystal grain diameter of 40 μm or less, and having a limited (Σ 3+ Σ 9) grain boundary length ratio.

Patent document 2 proposes a high-purity copper sputtering target material in which the purity of Cu other than O, H, N, C is 99.99998 mass% or more, the upper limit of the content of Al, Si, Fe, S, Cl, O, H, N, and C is limited, and the ratio of the large-tilt-angle grain boundary length is limited.

Patent document 3 proposes a high-purity copper sputtering target material in which the purity of Cu other than O, H, N, C is 99.99998 mass% or more, the upper limit of the content of Al, Si, Fe, S, Cl, O, H, N, and C is limited, and the local orientation difference of the crystal orientation obtained by crystal orientation measurement using electron back scattering diffraction is limited.

Patent document 4 proposes a high-purity copper sputtering target material in which the purity of Cu other than O, H, N, C is 99.99998 mass% or more, the upper limit of the content of Al, Si, Fe, S, Cl, O, H, N, and C is limited, and the number of molecules of the off-gas emitted by the temperature-programmed desorption gas analyzer is limited.

Patent document 5 proposes a high-purity copper sputtering target material in which the purity of Cu other than O, H, N, C is 99.99998 mass% or more, the upper limit of the content of Al, Si, Fe, S, Cl, O, H, N, and C is limited, and the average value of the differences in crystal orientation between one measurement point and all other measurement points within the same grain, which are obtained by crystal orientation measurement using electron back scattering diffraction, is limited.

Patent document 6 proposes a high-purity copper sputtering target material in which the purity of Cu other than O, H, N, C is 99.99998 mass% or more, the upper limit of the content of Al, Si, Fe, S, Cl, O, H, N, and C is limited, and the area ratio of crystals having a plane orientation of < 113 > ± 10 ° on the sputtering surface of the target, which is obtained by crystal orientation measurement using electron back scattering diffraction, is limited.

Patent document 7 proposes a high-purity copper sputtering target material in which the purity of Cu other than O, H, N, C is 99.99998 mass% or more, the upper limit of the content of Al, Si, Fe, S, Cl, O, H, N, and C is limited, and H in the gas components emitted by a temperature-programmed desorption gas analyzer is limited₂Number of O gas molecules.

Patent document 1: japanese patent laid-open publication No. 2014-201814

Patent document 2: japanese patent laid-open publication No. 2017-043790

Patent document 3: japanese patent laid-open publication No. 2017-071832

Patent document 4: japanese patent laid-open publication No. 2017-071833

Patent document 5: japanese patent laid-open publication No. 2017-071834

Patent document 6: japanese patent laid-open publication No. 2017-150008

Patent document 7: japanese patent laid-open publication No. 2017-150010

In recent years, further densification of wiring films has been demanded in semiconductor devices, flat panel displays such as liquid crystal and organic EL panels, touch panels, and the like, and it has been required to stably form wiring films finer and thinner than ever before. In addition, in order to form a film more quickly, a high voltage needs to be applied, and in this case, generation of abnormal discharge needs to be suppressed.

In the inventions described in patent documents 1 to 7, the effect of suppressing abnormal discharge can be sufficiently recognized.

However, in the inventions described in these patent documents 1 to 7, since the copper is made of high-purity copper, crystal grains are likely to grow and coarsen due to a thermal process during sputtering and the like when used for a long time, and crystal orientation is likely to be biased toward preferential orientation, so that generation of abnormal discharge (arc discharge) during film formation cannot be sufficiently suppressed, and there is a possibility that a wiring film having a finer and thinner film cannot be efficiently and stably formed.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a sputtering target material capable of sufficiently suppressing the occurrence of abnormal discharge (arc discharge) during film formation even when used for a long time, and capable of efficiently and stably forming a copper film that is miniaturized and made thinner.

In order to solve the above problems, a sputtering target according to the present invention contains one or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe in a total amount of 5 mass ppm or more and 50 mass ppm or less, and the remainder is composed of Cu and unavoidable impurities, and when the sputtering target is observed by an electron back scattering diffraction method, the average crystal grain diameter calculated on an area average excluding twins is X1(μm), and the maximum value of the intensity of a pole figure is X2, formula (1) is satisfied: 2500 > 19 XX 1+290 XX 2, and the crystal orientation measured by electron back scattering diffraction method has a local orientation difference (KAM) of 2.0 DEG or less and a relative density of 95% or more.

In the sputtering target having this structure, when the sputtering target is observed by the electron back scattering diffraction method, the average crystal grain diameter calculated by area average excluding the twins is X1(μm), and the maximum value of the intensity of the pole figure is X2, formula (1) is satisfied: 2500 > 19 × X1+290 × X2, and therefore the average crystal grain size is sufficiently small and the crystal orientation is random, and therefore the occurrence of abnormal discharge during sputter film formation can be sufficiently suppressed.

Further, since the alloy contains one or more elements selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe in a total amount of 5 mass ppm or more and 50 mass ppm or less, and the remainder is made up of Cu and unavoidable impurities, the elements Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe can suppress the growth of crystal grains even when heated, and can suppress the deviation of crystal orientation to a preferred orientation. Therefore, even if the film is used for a long time, the generation of abnormal discharge (arc discharge) during film formation can be sufficiently suppressed. Further, since the total content of the above elements is limited to 50 mass ppm or less, the copper film after film formation can be suppressed from significantly decreasing in specific resistance, and can be suitably used as a wiring film or the like. Further, a region where the concentration of the additive element is locally high (additive element high concentration region) is less likely to appear on the target sputtering surface, and the occurrence of abnormal discharge due to the additive element high concentration region can be suppressed.

Further, since the local alignment difference (KAM) of the crystal orientation measured by the electron back scattering diffraction method is 2.0 ° or less, the strain in the crystal grains is small, the generation of secondary electrons during sputtering is stabilized, and the generation of abnormal discharge can be suppressed.

Further, since the relative density is 95% or more, the number of internal voids is small, and the generation of abnormal discharge due to the voids can be suppressed.

Here, in the sputtering target of the present invention, it is preferable that the average value (GOS) of the differences in crystal orientation between one measurement point and all other measurement points within the same crystal grain, as measured by the electron back scattering diffraction method, is 4 ° or less.

In this case, since the average value (GOS) of the local orientation differences of the crystal orientation between one measurement point and all other measurement points in the same crystal grain is 4 ° or less, the local orientation differences in the crystal grain are small, the generation of secondary electrons during sputtering is stabilized, and the generation of abnormal discharge can be suppressed.

The sputtering target of the present invention may contain one or two or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe in a total amount of 10 mass ppm to 50 mass ppm.

In this case, since one or two or more elements selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe are contained in a total amount of 10 mass ppm or more, the growth of crystal grains can be reliably suppressed even when the heating is performed by these Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe elements, and the deviation of crystal orientation to the preferred orientation can be more effectively suppressed.

Further, in the sputtering target of the present invention, it is preferable that when the sputtering target is observed by an electron back scattering diffraction method, and an average crystal grain diameter calculated by area average excluding twins is X1(μm), and a maximum value of intensity of a pole figure is X2, formula (2) is satisfied: 1600 > 11 XX 1+280 XX 2.

In this case, when the sputtering target is observed by the electron back scattering diffraction method, the average crystal grain diameter calculated by area averaging excluding the twins is X1(μm), and the maximum value of the intensity of the pole figure is X2, formula (2) is satisfied: 1600 > 11 × X1+280 × X2, the average crystal grain size further decreases and the crystal orientation is more random, thereby further suppressing the occurrence of abnormal discharge during sputter film formation.

In the sputtering target of the present invention, the local misorientation (KAM) of the crystal orientation measured by the electron back scattering diffraction method may be 1.5 ° or less.

In this case, the strain in the grains is further reduced, the generation of secondary electrons during sputtering is further stabilized, and the generation of abnormal discharge can be further effectively suppressed.

The sputtering target of the present invention may be composed of a sintered body of copper powder.

In this case, the average crystal grain size X1 of the sputtering target can be reduced by adjusting the particle size of the copper powder to be the raw material. Further, the orientation of the crystal is likely to be random, and the maximum value X2 of the intensity of the pole figure becomes small. Therefore, the occurrence of abnormal discharge during sputter film formation can be more reliably suppressed.

According to the present invention, it is possible to provide a sputtering target material capable of sufficiently suppressing the occurrence of abnormal discharge (arc discharge) during film formation even when used for a long time, and capable of efficiently and stably forming a copper film that is miniaturized and made thin.

Detailed Description

A sputtering target according to an embodiment of the present invention will be described below.

The sputtering target of the present embodiment is used for forming a copper film on a substrate, which is used as a wiring film in a semiconductor device, a flat panel display such as a liquid crystal or organic EL panel, a touch panel, or the like.

The sputtering target of the present embodiment has the following composition: contains one or more kinds selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni and Fe in a total amount of 5 to 50 mass ppm, and the balance is Cu and unavoidable impurities.

In the sputtering target of the present embodiment, when the average crystal grain diameter calculated by area averaging, excluding twins, is X1(μm) and the maximum value of the intensity of the pole figure is X2 as observed by the electron back scattering diffraction method, formula (1) is satisfied: 2500 > 19 XX 1+290 XX 2.

In the sputtering target of the present embodiment, the local alignment difference (KAM) of the crystal orientation measured by the electron back scattering diffraction method is 2.0 ° or less.

In the sputtering target of the present embodiment, the relative density is 95% or more.

In the sputtering target of the present embodiment, it is preferable that the average value (GOS) of the differences in crystal orientation between one measurement point and all other measurement points within the same crystal grain, as measured by the electron back scattering diffraction method, is 4 ° or less.

The following is a description of the reason why the sputtering target of the present embodiment defines the composition, the relational expression between the average crystal grain diameter and the maximum value of the intensity of the pole figure, the local orientation difference (KAM) of the crystal orientation measured by the electron back scattering diffraction method, and the average value (GOS) of the crystal orientation difference between one measurement point and all other measurement points in the same crystal grain measured by the electron back scattering diffraction method, as described above.

(one or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni and Fe)

The elements Ag, As, Pb, Sb, Bi, Cd, Sn, Ni and Fe have the function of inhibiting the growth of crystal grains by adding a trace amount of the elements to pure copper. Therefore, it is possible to suppress the coarsening of crystal grains and the deviation of crystal orientation to the preferred growth orientation due to the thermal process at the time of sputtering. On the other hand, if the Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe are excessively contained, the specific resistance value of the copper film after film formation increases, and the characteristics As a wiring film may become insufficient. Further, there is a possibility that a region where the concentration of the additive element is high (additive element high concentration region) and a region where the concentration of the additive element is low (additive element low concentration region) are generated on the target sputtering surface, and electric charges are accumulated in the additive element high concentration region, thereby easily causing abnormal discharge.

As is clear from the above, in the present embodiment, the total content of one or two or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe is limited to a range of 5 mass ppm or more and 50 mass ppm or less.

In order to reliably suppress the growth of crystal grains, the lower limit of the total content of one or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe is preferably 10 mass ppm or more, more preferably 15 mass ppm or more, and still more preferably 20 mass ppm or more. On the other hand, in order to further suppress an increase in the specific resistance value of the copper film to be formed and further suppress the generation of abnormal discharge due to the high concentration region of the additive element, the upper limit of the total content of one or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe is preferably 40 mass ppm or less, and more preferably 35 mass ppm or less.

(relation of average crystal grain diameter to maximum value of intensity of pole figure)

In order to suppress abnormal discharge during sputtering, it is preferable that the crystal grain size is fine and the crystal orientation is random.

In the present embodiment, a sputtering test using various sputtering targets was performed, and it was confirmed that, as a result of a multiple regression calculation using the average crystal grain size X1(μm) and the maximum value X2 of the intensity of a pole figure indicating the orientation of crystal orientation as explanatory variables and the number of abnormal discharges as target variables, the following equation (1) was satisfied: 2500 > 19 XX 1+290 XX 2, and the number of abnormal discharges during sputtering can be sufficiently reduced. The average crystal grain size X1 is a value obtained by observing the crystal grain size by Electron Back Scattering Diffraction (EBSD) method and calculating the average area excluding the twins.

Here, in order to further reduce the number of abnormal discharges, 19 × X1+290 × X2 is preferably less than 2200, and more preferably less than 2000.

In the embodiment, the average crystal grain diameter X1(μm) and the maximum value X2 of the intensity of the pole figure more preferably satisfy formula (2): 1600 > 11 XX 1+280 XX 2.

(local orientation difference of crystal orientation)

When the local Misorientation (KernelAverage Misorientation): KAM) of the crystal orientation measured by the electron back scattering diffraction method (EBSD method) exceeds 2.0 °, the strain in the crystal grains is large, and therefore, in the region where the strain is present, the generation of secondary electrons during sputtering may become unstable.

Therefore, in the present embodiment, the local alignment difference (KAM) of the crystal orientation measured by the electron back scattering diffraction method is set to 2.0 ° or less, whereby the strain in the crystal grains can be reduced and the generation of secondary electrons during sputtering can be stabilized.

In order to reliably stabilize the generation of secondary electrons during sputtering, the KAM is preferably 1.5 ° or less, more preferably 1.0 ° or less, and still more preferably 0.7 ° or less.

(relative Density)

If the relative density of the sputtering target is low, a large number of pores are present inside, and abnormal discharge may occur due to the pores during sputtering film formation.

Therefore, in the present embodiment, the relative density of the sputtering target is set to 95% or more.

The relative density of the sputtering target is preferably 97% or more, and more preferably 98% or more.

(average value of crystal orientation differences between one measurement point and all other measurement points within the same grain)

When the average value (GOS) of the differences in crystal orientation between one measurement point and all other measurement points in the same crystal grain, as measured by the electron back scattering diffraction method (EBSD method), exceeds 4 °, the strain is large, and therefore the generation of secondary electrons during sputtering may become unstable in a region where the strain is present.

Therefore, in the present embodiment, the average value (GOS) of the differences in crystal orientation between one measurement point and all other measurement points in the same crystal grain, as measured by the electron back scattering diffraction method, is set to 4 ° or less, whereby the strain in the crystal grain can be reduced and the generation of secondary electrons during sputtering can be stabilized.

In order to reliably stabilize the generation of secondary electrons during sputtering, the GOS is preferably 3 ° or less.

Next, a method for manufacturing a sputtering target according to the present embodiment will be described. The sputtering target of the present embodiment can be produced by a melt casting method and a powder sintering method.

Hereinafter, a method for producing a sputtering target composed of an ingot-shaped material produced by a melt casting method and a method for producing a sputtering target composed of a sintered body produced by a powder sintering method will be described.

(melt casting method)

Electrolytic copper having a copper purity of 99.99 mass% or more is prepared and subjected to electrolytic purification. The electrolytic copper was used as an anode, a titanium plate was used as a cathode, and the anode and the cathode were immersed in an electrolytic solution to perform electrolysis. Among them, an electrolyte prepared by diluting copper nitrate as a reagent with water and further adding hydrochloric acid was used. Thus, by adding hydrochloric acid to the copper nitrate electrolytic solution, generation of nitrous acid gas can be suppressed, and the amount of impurities in the electrolytic copper plating can be reduced (see japanese patent No. 3102177). By performing such electrolytic purification, high-purity copper having a Cu purity of 99.99998 mass% or more, excluding O, H, N, C, can be obtained.

Next, this high-purity copper is melted in a vacuum melting furnace As a melting raw material, and elements Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe are added to the obtained copper melt so that the total content thereof is in the range of 5 mass ppm or more and 50 mass ppm or less, followed by casting to produce a copper ingot having the above composition.

The obtained copper ingot is hot forged at a temperature ranging from 700 ℃ to 900 ℃. Thereby, the cast structure is broken to adjust to a structure having equiaxed grains.

Then, the hot forged material is hot-rolled at a temperature ranging from 700 ℃ to 900 ℃ to refine the crystal grain size. The reduction ratio per pass in the hot rolling is preferably in the range of 5% to 15%.

Then, the hot rolled material is subjected to warm working in a temperature range of 100 ℃ to 200 ℃. The working ratio per pass in the warm working is preferably in the range of 5% to 10%.

Subsequently, the warm worked material is subjected to cold rolling. In order to refine the crystal grains, it is effective to randomize the crystal orientation and reduce the strain in the crystal grains, and to obtain a large rolling reduction at the time of cold rolling. This makes it easy to cause recrystallization in the heat treatment after cold working to be performed subsequently, and reduces the strain in the grains. Therefore, the rolling reduction in the first rolling pass is preferably in the range of 15% to 25%. The rolling reduction in the entire rolling is preferably 40% or more.

Subsequently, the cold worked material is subjected to a recrystallization heat treatment. The heat treatment temperature is preferably 250 ℃ to 350 ℃ inclusive, and the holding time is preferably 2 hours to 3 hours inclusive.

Further, by repeating the cold working and the heat treatment a plurality of times, it is possible to refine crystal grains, randomize crystal orientation, and reduce strain in the crystal grains.

Then, a sputtering target having a predetermined size is produced by machining. As described above, a sputtering target material made of an ingot processing material was produced. In addition, in the sputtering target material composed of the ingot processing material manufactured by the melt casting method, the number of pores existing inside is small, and the relative density is 95% or more.

(powder sintering method)

High-purity copper having a copper purity of 99.9999 mass% or more is melted, and Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe elements are added so that the total content is in the range of 5 mass ppm or more and 50 mass ppm or less, and cast to obtain a copper ingot. The copper ingot was rolled to form an anode plate. Then, a rolled sheet of high-purity copper having a copper purity of 99.9999 mass% or more was used as a cathode plate.

The anode plate and the cathode plate were immersed in a copper sulfate solution, and a direct current was passed under normal electrolysis conditions to obtain electrolytic copper powder. The electrolytic powder obtained was subjected to acid washing/neutralization, dehydration, drying, and sieving to obtain electrolytic copper powder having a predetermined average particle size, which was then put into a cylindrical container together with a surfactant and subjected to rotary mixing for 48 hours. Thus, a raw material copper powder was obtained.

The obtained raw material copper powder was filled in a graphite mold, placed in a hot press, and sintered, thereby obtaining a sintered body. Here, the sintering conditions were as follows: an atmosphere in vacuum, a load in the range of 10MPa to 20MPa, a temperature rise rate in the range of 5 ℃/min to 20 ℃/min, a holding temperature in the range of 850 ℃ to 1050 ℃, and a holding time in the range of 1 hour to 2 hours.

Here, the sintering conditions are set so that the relative density of the sintered body becomes 95% or more.

Then, a sputtering target having a predetermined size is produced by machining. As described above, a sputtering target composed of a sintered body was produced.

As described above, the sputtering target of the present embodiment is manufactured.

According to the sputtering target of the present embodiment having the above configuration, when the average crystal grain diameter calculated by area average excluding the twins is X1(μm) and the maximum value of the intensity of the pole figure is X2 as observed by the electron back scattering diffraction method (EBSD method), expression (1) is satisfied: 2500 > 19 XX 1+290 XX 2, so the average crystal grain diameter is sufficiently small, and the crystal orientation is random, so the generation of abnormal discharge during sputter film formation can be sufficiently suppressed.

And, when the average crystal grain diameter X1(μm) and the maximum value X2 of the intensity of the pole figure satisfy formula (2): when 1600 > 11 × X1+280 × X2, the average crystal grain diameter is smaller and the crystal orientation is more random, so that the occurrence of abnormal discharge during sputter film formation can be further suppressed.

In addition, since the sputtering target material of the present embodiment contains one or two or more elements selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe in a total amount of 5 mass ppm or more and 50 mass ppm or less, and the remainder is made up of Cu and unavoidable impurities, the Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe elements can suppress the growth of crystal grains even when heated, and can suppress the deviation of crystal orientation to a preferred orientation. Therefore, even if the film is used for a long time, the generation of abnormal discharge (arc discharge) during film formation can be sufficiently suppressed.

Further, the copper film formed can be suppressed from significantly decreasing in specific resistance, and can be suitably used as a wiring film or the like.

In addition, when one or two or more selected from Ag, As, Pb, Sb, Bi, Cd, Sn, Ni, and Fe are contained in a total amount of 10 mass ppm or more, the growth of crystal grains during heating can be more reliably suppressed.

In the sputtering target of the present embodiment, since the local orientation difference (KAM) of the crystal orientation measured by the electron back scattering diffraction method (EBSD method) is 2.0 ° or less, the strain in the crystal grains is small, the generation of secondary electrons during sputtering is stable, and the generation of abnormal discharge can be suppressed.

When the local alignment difference (KAM) of the crystal orientation measured by the electron back scattering diffraction method (EBSD method) is 1.5 ° or less, the generation of secondary electrons during sputtering is further stabilized, and the generation of abnormal discharge can be reliably suppressed.

In the sputtering target of the present embodiment, since the relative density is set to 95% or more, voids existing inside the sputtering target are small, and the occurrence of abnormal discharge due to voids at the time of sputter film formation can be suppressed.

In the sputtering target of the present embodiment, when the average value (GOS) of the differences in crystal orientation between one measurement point and all other measurement points in the same crystal grain measured by the electron back scattering diffraction method (EBSD method) is 4 ° or less, the local differences in orientation in the crystal grain are small, the generation of secondary electrons during sputtering is stabilized, and the generation of abnormal discharge can be suppressed.

In the sputtering target of the present embodiment, when the sputtering target is composed of a sintered body of copper powder, the average crystal grain diameter X1 of the sputtering target can be reduced by adjusting the particle diameter of the copper powder serving as a raw material, the orientation of the crystal is easily random, and the maximum value X2 of the intensity of the pole figure is small. Therefore, the occurrence of abnormal discharge during sputter film formation can be more reliably suppressed.

While the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and modifications can be made as appropriate without departing from the technical spirit of the present invention.

In the present embodiment, a sputtering target for forming a copper film as a wiring film is described as an example, but the present invention is not limited thereto, and can be applied to a case where a copper film is used for other applications.

The manufacturing method is not limited to this embodiment, and the optical fiber can be manufactured by another manufacturing method.