TW202302890A - Ta-B sputtering target - Google Patents

Abstract

This Ta-B sputtering target contains Ta and B, and is characterized by having Ta-B compound particles comprising one or more kinds selected from among Ta2B, Ta3B2, Ta3B4, Ta5B6, TaB, and TaB2, wherein the abundance ratio of elementary substances of B in the B content is 50% or less.

Description

Ta-B sputtering target

The present invention relates to a Ta-B sputtering target used when forming a thin film containing Ta and B (hereinafter referred to as a Ta-B thin film). The present invention claims priority based on Japanese Patent Application No. 2021-015279 filed in Japan on February 2, 2021, and the contents thereof are incorporated herein.

In the past, for example, the above-mentioned Ta-B film (a nitride film containing Ta and B, or a film containing Ta and B oxide film). Here, in Patent Documents 1 and 2, it is proposed to use a sputtering target containing Ta and B (hereinafter referred to as a Ta-B sputtering target) to perform nitrogen-reactive film formation or oxygen-reactive film formation to form the above-mentioned The method of EUV absorbing film. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Publication No. WO2016/204051 [Patent Document 2] Japanese Patent No. 5760990

[Problem to be solved by the invention]

However, the Ta-B sputtering targets described in Patent Documents 1 and 2 are produced by mixing Ta powder and B powder and sintering them. For this reason, in the Ta-B sputtering target, it becomes the coexistence structure of the conductor Ta and the insulator B. When sputtering a film using such a Ta-B sputtering target, an abnormal discharge occurs starting from the insulator B, which causes dust. However, as mentioned above, since the EUV blank mask is used for forming fine wiring patterns, it is impossible to form a Ta-B film (a nitride film containing Ta and B) when dust is generated during sputtering film formation. , or oxide films containing Ta and B), doubts about the use of EUV absorbing films.

This invention is made in view of the above-mentioned circumstances, and provides a method that can suppress the generation of dust caused by abnormal discharge, and can stably form a Ta-B film (a nitride film containing Ta and B, or an oxide film containing Ta and B). Ta-B sputtering target for the purpose. [As a means to solve the problem]

In order to solve the above-mentioned problems, the Ta-B sputtering target of the present invention is _a Ta-B sputtering target containing Ta and B, _which contains _Ta2B , _{Ta3B2 , Ta3B4} , _Ta5B6 , The Ta-B compound particles formed by _one or two or more kinds of TaB and TaB are characterized in that the presence ratio of the monomer B in the contained B is 50% or less.

According to the Ta-B sputtering target of the present invention, through the Ta-B compound particles having a conductor, to ensure the B component, the existence ratio of the monomer B of the insulator in the contained B can be suppressed below 50%. When forming a film by sputtering, it can suppress the abnormal discharge caused by the monomer B, and suppress the generation of dust.

Here, in the Ta-B sputtering target of the present invention, the roundness of the aforementioned Ta-B compound particles is preferably 0.3 or more. At this time, when the roundness of the above-mentioned Ta-B compound particles is more than 0.3, the Ta-B compound particles can be suppressed from becoming acicular or trapezoidal, and the ends of the Ta-B compound particles during film formation by sputtering can be suppressed. The generation of abnormal discharge at the starting point can also suppress the generation of dust.

Moreover, in the Ta-B sputtering target of this invention, it is preferable that content of B exists in the range of 0.3 mass% or more and 10 mass% or less. At this time, because the content of B is within the above range, in the formed Ta-B thin film, optical properties suitable for EUV anti-reflection characteristics or absorption characteristics can be obtained, and Ta can be formed into a film that is especially suitable for EUV absorption films. -B film.

In addition, the Ta-B sputtering target of the present invention further contains one or more selected from Ta nitride, B nitride, Ta oxide, and B oxide, and the total content of N and O is 20 mass% or less Whichever is better. At this time, because it contains one or two or more selected from Ta nitride, B nitride, Ta oxide, and B oxide, it is not necessary to perform nitrogen-reactive film formation or oxygen-reactive film formation, and a film containing Ta and A nitride film of B, or an oxide film containing Ta and B. In addition, since the film can be formed without introducing reactive gas such as oxygen or nitrogen, it can be applied to ion beam sputtering which generates less dust. Moreover, since the total content of N and O is limited to less than 20mass%, in the formed Ta-B thin film, optical properties suitable for EUV anti-reflection characteristics or absorption characteristics can be obtained, and the film formation is especially suitable for EUV absorption Film Ta-B thin film.

In addition, in the Ta-B sputtering target of the present invention, the total content of Fe, Ni, Cr, Cu, Na, and K as metal impurities is preferably 10000 massppm or less. At this time, the total content of Fe, Ni, Cr, Cu, Na, and K of metal impurities is limited to less than 10,000 massppm, which can suppress the occurrence of abnormal discharge starting from metal impurities during sputtering film formation, and can also suppress dust. of the generation.

Moreover, in the Ta-B sputtering target of this invention, it is preferable that the average crystal particle diameter is 50 micrometers or less. At this time, since the average crystal particle size is limited to 50 μm or less, even if sputtering is performed, unevenness that is difficult to occur on the sputtered surface can be further suppressed from generating abnormal discharge during sputtering film formation, and can further suppress the generation of dust.

Moreover, in the Ta-B sputtering target of this invention, it is preferable that surface roughness Ra (arithmetic mean roughness) is 1.6 micrometers or less. In this case, since the surface roughness Ra is 1.6 μm or less, the occurrence of abnormal discharge during film formation by sputtering can be further suppressed, and the generation of dust can be further suppressed.

Also, in the Ta-B sputtering target of the present invention, the density ratio is preferably 90% or more. At this time, the density ratio is more than 90% and the voids are less, so that the occurrence of abnormal discharge during sputtering film formation can be further suppressed, and the generation of dust can be further suppressed.

Moreover, in the Ta-B sputtering target of this invention, it is preferable that resistivity is 1 Ωcm or less. In this case, since the resistivity is 1 Ωcm or less, sufficient electrical conductivity can be ensured, the occurrence of abnormal discharge during film formation by sputtering can be further suppressed, and the generation of dust can be further suppressed. [Invention effect]

According to the present invention, it is possible to provide Ta-B sputtering that suppresses the generation of dust caused by abnormal discharge and can stably form a Ta-B film (a nitride film containing Ta and B, or an oxide film containing Ta and B). target.

Hereinafter, it demonstrates referring drawings attached to the Ta-B sputtering target which concerns on embodiment of this invention. The Ta-B sputtering target of this embodiment is used, for example, to form a Ta-B film (a nitride film containing Ta and B, or a film containing Ta and the oxide film of B).

However, in the Ta-B sputtering target of the present embodiment, the shape is not limited, and it may be a rectangular plate-shaped sputtering target whose sputtering surface is rectangular, or a disc-shaped sputtering target whose sputtering surface is circular. Plated target. Alternatively, a cylindrical sputtering target whose sputtering surface becomes a cylindrical surface may also be used.

Regarding the Ta-B sputtering target of this embodiment, there is a Ta-B compound formed by one or more kinds selected from Ta ₂ B, Ta ₃ B ₂ , Ta ₃ B ₄ , Ta ₅ B ₆ , TaB, and TaB ₂ particle. Ta is contained in the Ta-B sputtering target as a main component. For the Ta-B sputtering target as a whole, it is preferable to contain 80 mass% or more and 99.9 mass% or less. And, in the Ta—B sputtering target of this embodiment, the abundance ratio of the monomer B which does not combine with Ta among B contained is 50% or less. That is, in the Ta—B sputtering target of this embodiment, 50% or more of contained B exists in the form of a compound.

However, the abundance ratio of the monomer B in the contained B was calculated from the peak intensity ratio of the XRD measurement as shown in FIG. 1 and FIG. 2 . That is, XRD measurement is carried out, as shown in the following formula (1), the peak intensity attributable to monomer B is divided by the sum of the peak intensity attributable to the Ta-B compound and the peak intensity attributable to monomer B, and multiplied by The ratio above 100 is taken as the presence ratio (%) of monomer B. However, the areas for measuring the peak intensities of the monomer B and the Ta-B compound are shown below. (1) Formula: Existence ratio of monomer B (%)={(B monomer)/(Ta-B compound+B monomer)} Monomer B: (104) face Ta ₂ B: (211) face Ta ₃ B ₂ : (201) plane Ta ₃ B ₄ : (031) plane Ta ₅ B ₆ : (510) plane TaB: (021) plane TaB ₂ : (101) plane

Moreover, in the Ta-B sputtering target of this embodiment, it is preferable that the roundness of a Ta-B compound particle is 0.3 or more. However, the roundness of the Ta-B compound particles is defined by the following formula from the area and perimeter of the Ta-B compound particles when observing the Ta-B sputtering target. Circularity=4π×(area)/(circumference) ² For example, the circularity of Ta-B compound particles is calculated from the image obtained by observing the Ta-B sputtering target through the above formula. This image is preferably obtained from the surface of the Ta-B sputtering target in an area ranging from 10,000 μm ² to 100,000 μm ² . The calculation of the true circularity can be performed based on the images of a plurality of Ta-B compound particles. At this time, the average of the roundness of the plural numbers can be taken as the roundness of the Ta-B compound particles.

Here, an example of the microstructure observation photograph of the Ta-B sputtering target of this embodiment is shown in FIG. 3 . In this Fig. 3, the white part is the monomer Ta, the dark part other than the white part is the Ta-B compound particle ( _TaB2 in Fig. 3), and the black part is the void.

Moreover, in the Ta-B sputtering target of this embodiment, it is preferable that content of B exists in the range of 0.3 mass% or more and 10 mass% or less. Furthermore, in the Ta-B sputtering target of this embodiment, it is preferable that the total content of Fe, Ni, Cr, Cu, Na, and K of metal impurities is 10000 massppm or less.

In addition, _{in the} Ta _- B sputtering target of the present _embodiment , further containing ) of one or more, preferably with a total content of N and O below 20mass%.

Furthermore, in the Ta-B sputtering target of this embodiment, it is preferable that the average crystal particle diameter is 50 micrometers or less. Moreover, in the Ta-B sputtering target of embodiment, it is preferable that surface roughness Ra is 1.6 micrometers or less.

Furthermore, in the Ta-B sputtering target of this embodiment, it is preferable that the density ratio is 90% or more. Moreover, in the Ta-B sputtering target of embodiment, it is preferable that resistivity is 1 Ωcm or less.

In the following, in the Ta-B sputtering target of this embodiment, the Ta-B compound particles, the phase composition, the abundance ratio of monomer B in B, the roundness of the Ta-B compound particles, and the B content , Ta or B nitrides and oxides, content of metal impurities, average crystal particle size, surface roughness Ra, density ratio, and resistivity, showing the reasons specified above.

(Ta-B Compound Particles) The Ta-B sputtering target according to the present embodiment contains one species selected from Ta ₂ B, Ta ₃ B ₂ , Ta ₃ B ₄ , Ta ₅ B ₆ , TaB, and TaB ₂ as described above. Or two or more kinds of Ta-B compound particles formed. Since these Ta-B compound particles are electrical conductors, by containing B as the Ta-B compound particles, it is possible to suppress the occurrence of abnormal discharge during sputtering film formation. The area ratio of the Ta-B compound particles on the sputtering surface is 50%-99%, preferably 60%-97%, more preferably 70%-95%.

(Existence ratio of monomer B) As described above, by containing B in the Ta—B compound particles as a conductor, the abundance ratio of the monomer B in the insulator can be reduced, and the occurrence of abnormal discharge during sputtering film formation can be suppressed. Therefore, in this embodiment, the abundance ratio of the monomer B contained in B of a Ta-B sputtering target is made into 50 % or less. However, in order to further suppress the occurrence of abnormal discharge during film formation by sputtering, the ratio of monomer B contained in B is preferably 20% or less, more preferably 10% or less, more preferably 5% or less. Although not particularly limited, the lower limit of the abundance ratio of B may be 0.1%.

(Circularity of Ta-B Compound Particles) The above-mentioned Ta-B compound particles may be acicular or trapezoidal depending on the conditions at the time of production. When the Ta-B compound particles are in the shape of needles or trapezoids, there is a possibility that an abnormal discharge may occur at the end of these structures as a starting point during film formation by sputtering. Therefore, in order to further suppress abnormal discharge during film formation by sputtering, it is preferable to set the roundness (4π×(area)/(circumference) ² ) of Ta—B compound particles to 0.3 or more. However, the roundness of the Ta-B compound particles is preferably at least 0.4, more preferably at least 0.5. Although not particularly limited, the upper limit of the roundness of the Ta-B compound particles may be 1.0.

(Content of B) In the Ta-B sputtering target of this embodiment, when the content of B is within the range of 0.3 mass% or more and 10 mass% or less, the reflection and absorption characteristics of EUV in the formed Ta-B thin film can be sufficiently ensured. Therefore, in this embodiment, the content of B is preferably in the range of 0.3 mass% or more and 10 mass% or less. However, the content of B is preferably 0.5 mass% or more, more preferably 1.0 mass% or more, more preferably 1.3 mass% or more. Also, the content of B is preferably 5.0 mass% or less, more preferably 3.0 mass% or less, more preferably 2.0 mass% or less.

(Nitrides and oxides of Ta or B) When the Ta-B sputtering target of this embodiment contains one or more kinds selected from Ta nitrides, B nitrides, Ta oxides, and B oxides, it is not necessary to perform nitrogen-reactive film formation or oxygen-reactive film formation. For film formation, it can form a nitride film containing Ta and B, or an oxide film containing Ta and B. Then, by limiting the total content of N and O to less than 20mass%, the formed Ta-B thin film can sufficiently ensure EUV reflection and absorption characteristics. However, the total content of N and O is preferably at most 15 mass%, more preferably at most 12 mass%. The lower limit of the total content of N and O is not particularly limited, but it is preferably 0.5 mass% or more, more preferably 1.0 mass% or more.

(Content of metal impurities) In the Ta-B sputtering target of this embodiment, the total content of Fe, Ni, Cr, Cu, Na, and K as metal impurities is limited to a low level, which can suppress the abnormality starting from the metal impurities during sputtering film formation. generation of discharge. Therefore, in this embodiment, it is preferable to limit the total content of Fe, Ni, Cr, Cu, Na, and K as metal impurities to 10000 massppm or less. However, the total content of Fe, Ni, Cr, Cu, Na, and K of metal impurities is preferably 1000 massppm or less. More preferably, it is 500 massppm or less. Although not particularly limited, the lower limit of the total content of metal impurities may be 10 massppm.

(average crystal particle diameter) In the Ta-B sputtering target of this embodiment, since the average crystal grain size is reduced, even if sputtering is performed, unevenness hardly occurs on the sputtering surface, and the occurrence of abnormal discharge during sputtering film formation can be further suppressed. Therefore, in this embodiment, it is preferable to limit the average crystal particle size to 50 μm or less. Also, the average crystal particle diameter is preferably 30 μm or less, more preferably 20 μm or less. Although not particularly limited, the lower limit of the average crystal particle size may be 0.1 μm.

(surface roughness Ra) In the Ta-B sputtering target of the present embodiment, by reducing the surface roughness (arithmetic mean roughness) Ra, the occurrence of abnormal discharge during sputtering film formation can be further suppressed. Therefore, in this embodiment, it is preferable that the surface roughness Ra is limited to 1.6 μm or less. In addition, the surface roughness Ra is preferably 1.2 μm or less, more preferably 0.6 μm or less. Although not particularly limited, the lower limit of the surface roughness Ra may be 0.01 μm.

(density ratio) In the Ta-B sputtering target of this embodiment, by increasing the density ratio, the internal voids are reduced, and the occurrence of abnormal discharge during sputtering film formation can be further suppressed. Therefore, in this embodiment, the density ratio is preferably 90% or more. However, the density ratio is preferably at least 95%, more preferably at least 97%. Although not particularly limited, the upper limit of the density ratio may be 100%.

(resistivity) In the Ta-B sputtering target of this embodiment, by containing the above-mentioned Ta-B compound particles, by suppressing the abundance ratio of the monomer B of the insulator to 50% or less, the resistivity becomes low, and the electrical conductivity can be sufficiently ensured. It also suppresses the occurrence of abnormal discharge during sputtering film formation. Therefore, in this embodiment, it is preferable to limit the resistivity to 1 Ωcm or less. However, the resistivity is preferably 0.1 Ωcm or less, more preferably 0.01 Ωcm or less. Although not particularly limited, the lower limit of the resistivity may be 0.001 Ωcm.

Next, an example of the manufacturing method of the Ta-B sputtering target of this Embodiment mentioned above is demonstrated with reference to FIG. 4. FIG.

(Raw material powder preparation process S01) Prepare Ta powder with a purity of 99.9 mass% or higher and Ta-B compound powder with a purity of 99 mass% or higher. Also, Ta nitride powder, Ta oxide powder, B nitride powder, and B oxide powder with a purity of 99 mass% or more are prepared as needed. However, the average particle diameter of each of these raw material powders is preferably within a range of 0.1 μm or more and 50 μm or less. Here, the Ta-B compound powder should be acid-washed with aqua regia to remove metal impurities, washed with pure water, and then vacuum-dried to fully dry. In addition, the Ta-B compound powder may be pulverized by a ball mill or a jet mill in order to improve sinterability. The pulverization of the jet mill is to make the air volume of the jet mill more than 0.3m ³ /min and the pressure to be more than 0.6MPa.

(Raw material powder mixing project S02) The above raw material powders (Ta powder, Ta-B compound powder, Ta nitride powder, Ta oxide powder, B nitride powder, B oxide powder) were weighed to a specific ratio and mixed with a ball mill. The ball mill system can be wet or dry, for more uniform mixing, it is better to use wet.

(Sintering Engineering S03) Next, the mixed powder mixed as above is filled in a molding container, and the mixture is sintered by heating and pressing to obtain a sintered body. However, in this embodiment, sintering is performed by hot isostatic pressing (HIP). The sintering temperature of this sintering process S03 is in the range of 400°C to 2000°C, and the holding time of the sintering temperature is in the range of 60 minutes to 300 minutes. In addition, the pressurized pressure of the sintering process S03 is 25MPa or more. Here, in this embodiment, the sintering temperature is preferably 1000°C or higher, more preferably 1500°C or higher. Also, the sintering temperature is preferably lower than 1900°C, more preferably lower than 1800°C. Furthermore, the pressurized pressure is preferably 35 MPa or higher, more preferably 100 MPa or higher.

(Processing Engineering S04) Then, the obtained sintered body is mechanically processed to obtain a Ta-B sputtering target with a specific size. However, the Ta-B sputtering target is better to reduce the surface roughness Ra by mirror-finishing the abrasive grains.

Through the above process, the Ta-B sputtering target of this embodiment is manufactured.

According to the Ta-B sputtering target according to the present embodiment with the above structure, one or both of the conductors are selected from Ta ₂ B, Ta ₃ B ₂ , Ta ₃ B ₄ , Ta ₅ B ₆ , TaB, and TaB ₂ . At the same time, it can suppress the existence ratio of the monomer B of the insulator to less than 50% at the same time as the above-mentioned Ta-B compound particles. Therefore, during sputtering film formation, it can suppress the abnormal discharge caused by the monomer B and suppress the formation of dust. produce. Therefore, it is possible to form a Ta-B thin film that can be used as an EUV absorbing film for an EUV blank mask for forming fine wiring patterns.

In the Ta-B sputtering target of this embodiment, when the roundness of the Ta-B compound particles is 0.3 or more, the contained Ta-B compound particles can be suppressed from becoming acicular or trapezoidal, and the sputtering film formation can be suppressed. The end of the Ta-B compound particle is the starting point for the generation of abnormal discharge, and it can also suppress the generation of dust.

In the Ta-B sputtering target of this embodiment, when the content of B is in the range of 0.3 mass% or more and 10 mass% or less, in the formed Ta-B thin film, the decrease of the EUV reflective function can be suppressed, and the film can be formed. Especially suitable for Ta-B thin film of EUV absorbing film.

When the Ta-B sputtering target of this embodiment contains one or more kinds selected from Ta nitrides, B nitrides, Ta oxides, and B oxides, it is not necessary to perform nitrogen-reactive film formation or oxygen-reactive film formation. For film formation, it can form a nitride film containing Ta and B, or an oxide film containing Ta and B. Then, ion beam sputtering with less generation of dust can be applied. In addition, in the Ta-B sputtering target of this embodiment, the total content of N and O is limited to 20 mass% or less. In the Ta-B film formed into the film, the decrease of the EUV reflection function can be suppressed, and it is especially suitable for film formation. Ta-B film for EUV absorbing film.

In the Ta-B sputtering target of this embodiment, when the total content of Fe, Ni, Cr, Cu, Na, and K of metal impurities is 10000 massppm or less, it is possible to suppress the abnormality starting from the metal impurities during sputtering film formation. The generation of discharge can suppress the generation of dust.

In the Ta-B sputtering target of this embodiment, when the average crystal grain size is 50 μm or less, even if sputtering is performed, unevenness is hardly produced on the sputtering surface, and the occurrence of abnormal discharge during sputtering film formation can be further suppressed. It can also suppress the generation of dust.

In the Ta-B sputtering target of the present embodiment, when the surface roughness Ra is 1.6 μm or less, the occurrence of abnormal discharge during sputtering film formation can be further suppressed, and the generation of dust can be further suppressed.

In the Ta-B sputtering target of this embodiment, when the density ratio is 90% or more, there are few internal voids, and the occurrence of abnormal discharge during sputtering film formation can be further suppressed, and the generation of dust can be further suppressed.

In the Ta-B sputtering target of this embodiment, when the resistivity is 1Ωcm or less, the electrical conductivity can be ensured sufficiently, and the occurrence of abnormal discharge during sputtering film formation can be further suppressed, and the generation of dust can be further suppressed.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably without departing from the range of the technical idea of this invention. For example, in this embodiment, although the sintered body obtained by the hot isostatic pressing method (HIP) was demonstrated, it is not limited to this, The sintered body can also be obtained by the heat press method (HP). [Example]

Hereinafter, the results of confirmation experiments carried out to confirm the effectiveness of the present invention will be described.

Prepare Ta powder with a purity of 99.9mass% average particle diameter of 5 μm, B powder with a purity of 99mass% of an average particle diameter of 15.5 μm, and Ta-B compound powder with a purity of 99mass% of an average particle diameter of 8 μm (TaB ₂ powder), and a purity of 99mass% TaN powder with an average particle diameter of 3.7 μm, and Ta ₂ O ₅ powder with a purity of 99.9mass% and an average particle diameter of 3.6 μm, and BN powder with a purity of 99.9mass% and an average particle diameter of 0.8 μm, and a powder with a purity of 99mass% and an average particle diameter of 1.2 μm _{B2O3 powder} . However, the Ta-B compound powder (TaB ₂ powder) was acid-washed with nonyl water before mixing in order to remove metal impurities, and after washing with pure water, it was sufficiently dried by vacuum drying.

The above-mentioned raw material powders were weighed into the compounding ratio shown in Table 1, and mixed by a wet ball mill.

After removing the balls with a sieve, put the mixed powder in a carbon forming mold with an inner diameter of ϕ135mm, and use a heating and pressing device (HP) in a vacuum environment. Under the conditions of sintering temperature and pressure load shown in Table 1, Pressure sintering was carried out for 3 hours. Fill the above mixed powder into the SPCC mold of ϕ160mm, use (HIP), and carry out pressure sintering for 3 hours under the conditions of sintering temperature and pressure load shown in Table 1.

The surface of the obtained sintered body was rough-cut with diamond grindstone #100, and then finished with #400. Also, if necessary, the surface of the sintered body is subjected to mirror-finishing by abrasive grains. Thereby, the Ta-B sputtering target of the example of this invention and a comparative example was obtained.

The following items were evaluated about the obtained Ta-B sputtering target. The evaluation results are shown in Tables 2 to 4.

(XRD measurement) For the sputtering surface of the obtained Ta-B sputtering target, perform XRD measurement, and there will be sharp peaks belonging to Ta ₂ B, Ta ₃ B ₂ , Ta ₃ B ₄ , Ta ₅ B ₆ , TaB, and TaB ₂ , it was evaluated as "presence" of Ta-B compound particles. Also, divide the peak intensity attributable to monomer B by the sum of the peak intensity attributable to Ta-B compound and the peak intensity attributable to monomer B, and multiply the ratio by 100, as "existence of monomer B Compare(%)". At this time, the peak used for the Ta-B compound is the strongest. However, when the peak intensity of the Ta-B compound cannot be obtained, the abundance ratio (%) of the monomer B is 100%.

However, the DB card numbers of the monomer B and the Ta-B compound and the crystal plane of the main peak are shown below. Monomer B: DB card number 01-074-5416, crystal face (104) Ta ₂ B: DB card number 01-089-7191, crystal face (211) Ta ₃ B ₂ : DB card number 01-072-9378, Crystal face (201) Ta ₃ B ₄ : DB card number 01-089-3916, crystal face (031) Ta ₅ B ₆ : DB card number 01-080-0733, crystal face (510) TaB: DB card number 01- 089-2310, crystal face (021) TaB ₂ : DB card number 00-038-1462, crystal face (101)

(Content of B) A measurement sample was taken from the obtained Ta-B sputtering target, and the collected measurement sample was dissolved in ammonium fluoride aqueous solution, and ICP-AES analysis was performed to measure the B content (mass%) contained in the Ta-B sputtering target.

(N, O content) 1 g of a measurement sample was collected from the obtained Ta-B sputtering target, and the N,O content (mass%) was measured by a nitrogen and oxygen analyzer of LECO Company.

(Content of metal impurities) A measurement sample was collected from the obtained Ta-B sputtering target, and the collected measurement sample was dissolved in an ammonium fluoride aqueous solution, and analyzed by ICP-AES to measure the content (massppm) of Fe, Ni, Cr, and Cu. Furthermore, Na and K content (massppm) were measured using flame photometry. Then, the total content of these metal impurities was calculated.

(Roundness of Ta-B compound particles) Observation samples were collected from the obtained Ta-B sputtering target, and the sputtered surface was subjected to CP processing, and the area of 10,800 μm ² (90 μm×120 μm) was magnified by 1000 times through EPMA , photography compo like. The obtained image was binarized using the image analysis software imageJ, and only the area containing B was colored. The whitest area in the image is Ta, and the other components are considered to contain B components. The domain containing B means that when Ta-B compound particles exist, it is the domain of B contained in Ta-B compound particles or the domain of B contained in Ta-B compound particles and monomer B, and Ta-B compound particles do not exist In this case, it is the domain of B contained in the monomer B. For the coloring field, use the Shape Descriptors function to calculate the roundness (4π×(area)/(circumference) ² ) of the selected Ta-B compound particles. Among the obtained results, the average value of the roundness of Ta-B compound particles having a particle area of 1 μm ² or more was obtained. Carry out the same calculation for 5 arbitrary positions of the observed sample by using this operation, and obtain the average value.

(Average Particle Size) Observation samples were taken from the obtained Ta-B sputtering target, the sputtered surface was subjected to CP processing, and a COMPO image was taken at a magnification of 1000 times by EPMA in an area of 10,800 μm ² (90 μm×120 μm). Use the Find maxima function of the image analysis software imageJ to divide the particles from the maximum point in the particle range of the observed tissue of the sample, and use the Analyze particle function to measure the particle diameter of the obtained image, and calculate the average value. Carry out the same calculation for 5 arbitrary positions of the observed sample by using this operation, and obtain the average value.

(Density ratio) Calculate the density of the sintered body from the size and weight of the obtained Ta-B sputtering target (ϕ135mm, thickness 5mm). Divide the ratio of the dimensional density by the calculated density, and record it in the table as "Density Ratio". However, the calculated density is calculated according to the following formula. Calculated density (g/cm ³ )=100/{Ta preparation amount (mass%)/Ta density (g/cm ³ )+B preparation amount (mass%)/B density (g/cm ³ )+TaB compound preparation amount (mass%)/TaB compound density (g/cm ³ )+Additive preparation amount (mass%)/Additive density (g/cm ³ )} However, the additive system is TaN, BN, Ta ₂ O ₅ , B ₂ O ₃ .

(resistivity) For 5 places at any position on the sputtering surface of the obtained Ta-B sputtering target (ϕ135mm, thickness 5mm), use a low resistivity meter (Loresta-GP) manufactured by Mitsubishi Chemical Co., Ltd., and use the four-probe method The average value of the measured values is recorded in the table. The temperature at the time of measurement is 23±5°C, and the humidity is 50±20%. However, as a probe for measurement, an ASP probe was used.

(Sputtering characteristics) The obtained Ta-B sputtering target (ϕ135 mm, thickness 5 mm) was joined to a support plate made of Cu using In solder. Then, equip a sputtering device equipped with a particle monitor device (ISPM manufactured by Wexx Co., Ltd.), vacuum suction to 5 × 10 ^-4 Pa or less, and implement it under the conditions of Ar flow rate 30 sccm, pressure 0.67 Pa, and DC 615W for 12 hours. Sputtering. After 12 hours of sputtering, the number of abnormal discharges that were sputtered under the same conditions for 1 hour was counted by the arc counting function of the DC power supply (RPG-50 manufactured by mks company). In addition, simultaneously with the measurement of abnormal discharge, the number of dust in sputtering was measured with a dust monitor device. At this time, the total number of 5 types of measurement data with a dust size of 250nm or more and less than 600nm, 600nm or more and less than 1000nm, 1000nm or more and less than 3000nm, 3000nm or more and less than 3600nm, and 3600nm or more is used as the amount of particles in sputtering , Recorded in the table of the embodiment.

(Membrane Composition Analysis) A film with a thickness of 50 nm was formed on a Si substrate with a size of 20 mm x 20 mm under the same sputtering conditions as the abnormal discharge measurement. For the film-formed Si substrate, the quantitative analysis of the XPS device was carried out, and the quantitative values of B, N, and O obtained were recorded in Table 4.

In Comparative Example 1, no Ta-B compound particles were contained, and the abundance ratio of the monomer B was 100%. In Comparative Example 2, although a sharp peak attributed to _TaB was observed through XRD measurement, the abundance ratio of monomer B was 58%. In these comparative examples 1 and 2, abnormal discharges occurred many times during sputtering film formation, and the number of dust generated was also large.

On the other hand, in Examples 1 to 7 of the present invention, Ta-B compound particles were contained, and the abundance ratio of the monomer B was 50% or less. In addition, in Examples 1, 2, and 4 to 7 of the present invention, the abundance ratio of the monomer B contained in B was 0%. In Example 3 of the present invention, the presence ratio of monomer B contained in B is 42%, in Example 8 of the present invention, the presence ratio of monomer B contained in B is 13%, and in Example 9 of the present invention , the presence ratio of monomer B contained in B is 5%. In Examples 1 to 9 of the present invention, during sputtering film formation, the generation of abnormal discharge was suppressed, and the number of dust generated was reduced.

From the above, according to the examples of the present invention, it can be confirmed that the generation of dust caused by abnormal discharge can be suppressed, and the Ta-B thin film (nitride thin film containing Ta and B, or oxide thin film containing Ta and B) can be stably formed. etc.) Ta-B sputtering target.

[FIG. 1] It is a figure which shows the XRD measurement result of the Ta-B sputtering target concerning one embodiment of this invention. [ Fig. 2] Fig. 2 is a graph showing the XRD measurement results of a Ta-B sputtering target according to one embodiment of the present invention. [ Fig. 3] Fig. 3 is an observation photograph of a structure of a Ta-B sputtering target according to an embodiment of the present invention. [FIG. 4] It is a flow chart which shows the manufacturing method of the Ta-B sputtering target concerning one embodiment of this invention.

Claims (9)

A Ta-B sputtering target, which is a Ta-B sputtering target containing Ta and B, and is characterized in that it is selected from Ta ₂ B, Ta ₃ B ₂ , Ta ₃ B ₄ , Ta ₅ B ₆ , TaB, TaB ₂ One or more kinds of Ta-B compound particles formed, the ratio of monomer B contained in B is 50% or less. The Ta-B sputtering target according to claim 1, wherein the roundness of the Ta-B compound particles is 0.3 or more. The Ta-B sputtering target according to claim 1 or 2, wherein the content of B is within the range of 0.3 mass% to 10 mass%. The Ta-B sputtering target according to any one of claims 1 to 3, wherein it contains one or more of Ta nitrides, B nitrides, Ta oxides, B oxides, N and O The total content is 20 mass% or less. The Ta-B sputtering target according to any one of claims 1 to 4, wherein the total content of Fe, Ni, Cr, Cu, Na, and K as metal impurities is 10,000 massppm or less. The Ta-B sputtering target according to any one of claims 1 to 5, wherein the average crystal grain size is 50 μm or less. The Ta-B sputtering target according to any one of claims 1 to 6, wherein the surface roughness Ra is 1.6 μm or less. The Ta-B sputtering target according to any one of claims 1 to 7, wherein the density ratio is 90% or more. The Ta-B sputtering target according to any one of claims 1 to 8, wherein the resistivity is 1Ωcm or less.

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