Sputtering Target and Method for Producing the Same

Abstract

To provide a Cu-Al binary alloy sputtering target with a high Al content that is suppressed in crack in a sputtering target, and to provide a method for manufacturing the same.SOLUTION: A sputtering target comprises a sintered compact including a Cu-Al binary alloy and the balance inevitable impurities, where the content (at%) of Cu and Al meets the relational expression of 0.48≤Al / (Cu+Al)≤0.70 and the relative density is 95% or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a sputtering target (hereinafter, may be simply referred to as "target") and a method for manufacturing the same. In particular, the present invention relates to a sputtering target containing a Cu—Al binary alloy and a method for manufacturing the same.

Background Art

[0002] Some semiconductor devices have a multilayer wiring structure, and the multilayer wiring structure includes conductor wiring, an insulating film, a diffusion barrier layer, and the like. Conventionally, pure Cu has often been used for conductor wiring. However, in recent years, with the miniaturization of wiring, new problems such as electrical resistance have emerged. Along with this, a search for new materials for conductor wiring has been underway.

[0003] Patent Document 1 discloses various intermetallic compounds as wiring materials, and discloses CuAl2 as one of them. Further, Patent Document 1 discloses depositing pure metal targets of Cu and Al by DC sputtering to form the intermetallic compound CuAl2.

[0004] Patent Document 2 discloses manufacturing a sputtering target of a CuAl alloy through processes such as forging and rolling for use as a wiring material.

[0005] Patent Document 3 proposes using a target in which Cu and Al metals are alternately combined with a fan-shaped target surface shape instead of a sputtering target of a CuAl alloy. As a result of film formation using this sputtering target, it is disclosed that Cu and Al are compositionally mixed to a desired concentration, and a Cu—Al alloy film equivalent to a sputtering target made of a Cu—Al alloy is obtained.

[0006] Furthermore, Patent Document 4 also discloses a method of forming a film using an Al chip as an additive on a Cu target as a target.

Prior Art Documents

Patent Document

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] Since the intermetallic compound CuAl2 has attracted attention as a new wiring material, a method of forming a wiring by sputtering has been explored. Here, co-sputtering two types of targets of pure Cu and pure Al as in Patent Document 1 is complicated, and it is necessary to adjust various sputtering conditions to form the desired intermetallic compound.

[0009] Therefore, it is advantageous that the intermetallic compound CuAl2 is already formed at the time of sputtering. That is, a target material of CuAl2 is desired.

[0010] However, as a result of the study by the present inventor, based on the same method (processes such as rolling and forging) as the method disclosed in Patent Document 2, instead of the ingot of CuAl (Al: 0.01 wt%, 10 wt%) described in Patent Document 2, after preparing an ingot of CuAl2 and performing processing such as rolling and forging on this, it was found that the material cracked and a sputtering target could not actually be manufactured. This is considered to be because the toughness has decreased in CuAl2 due to an increase in the Al content compared to the case of CuAl (Al: 0.01 wt%, 10 wt%) described in Patent Document 2. Therefore, conventionally, it has been virtually impossible to realize a Cu-Al binary alloy sputtering target with a high Al content.

[0011] In the methods of Patent Documents 3 and 4, since materials having different properties such as thermal expansion and contraction characteristics are in proximity, there is a high possibility of cracking when the sputtering target is heated or cooled or during processing. Also, since different materials are used, there is a high risk of impurities being mixed in during sputtering. Therefore, from the viewpoint of suppressing cracking of the sputtering target and suppressing the mixing of impurities during sputtering, a Cu—Al binary alloy sputtering target having a more uniform composition is desirable rather than a sputtering target in which different components are combined.

[0012] The present invention has been completed in view of the above problems, and in one embodiment, an object is to provide a Cu—Al binary alloy sputtering target having a high Al content that can suppress cracking of the sputtering target and a method for manufacturing the same.

Means for Solving the Problems

[0013] As a result of intensive studies, the present inventors have found that a Cu—Al binary alloy sputtering target having a high Al content can be realized by using a sintered body as the sputtering target. The present invention has been completed based on the above findings and is exemplified below.

[0014] [1] A sputtering target composed of a sintered body containing a binary alloy of Cu and Al and the balance consisting of inevitable impurities, wherein the contents (at%) of Cu and Al satisfy the relational expression of 0.48 ≦ Al / (Cu + Al) ≦ 0.70, and the relative density is 95% or more. [2] When the Al content at a total of five points including the center position, the outer peripheral position, and the intermediate position in the middle of the sputtering surface of the sputtering target, which extends from the center to the outer periphery of the sputtering surface of the sputtering target and is arranged on two straight lines perpendicular to each other, is measured by inductively coupled plasma optical emission spectrometry, the difference between the maximum value and the minimum value of each content is 0.2 at% or less. The sputtering target according to [1]. [3] When analyzed with an X-ray diffractometer and quantitatively analyzed using the RIR (Reference Intensity Ratio) method for the result, the mass ratio of the total value of CuAl2 and CuAl is 95% or more. The sputtering target according to [1] or [2]. [4] The binary alloy of Cu and Al contains an intermetallic compound of CuAl2 and / or CuAl. The sputtering target according to any one of [1] to [3]. [5] The oxygen content is 50 to 1000 mass ppm. The sputtering target according to any one of [1] to [4]. [6] A method for manufacturing a sputtering target composed of a sintered body containing a binary alloy of Cu and Al, with the balance consisting of inevitable impurities, The content (at%) of Cu and Al in the sintered body satisfies the relational expression of 0.48 ≦ Al / (Cu + Al) ≦ 0.70, The method includes: A step of producing atomized powder, A step of sintering at least one of the atomized powder and the powder derived therefrom by hot pressing at a temperature of 550°C or higher And a method including this. [7] Before producing the atomized powder, the method further includes a step of producing an ingot so that the content (at%) of Cu and Al satisfies the relational expression of 0.48 ≦ Al / (Cu + Al) ≦ 0.70, The method according to [6], wherein the atomized powder is produced from the ingot. [8] The method according to [6] or [7], further comprising a step of further pulverizing the atomized powder before sintering. [9] The method according to any one of [6] to [8], wherein the binary alloy of Cu and Al contains an intermetallic compound of CuAl2 and / or CuAl. [Advantages of the Invention]

[0015] According to the present invention, it is possible to provide a Cu-Al binary alloy sputtering target having a high Al content and a method for producing the same, which can suppress cracking of the sputtering target. [Brief Description of the Drawings]

[0016]

Fig. 1

[0017] Next, embodiments of the present invention will be described. It should be understood that the present invention is not limited to the following embodiments, and that design changes, improvements, etc. can be appropriately made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0018] (1. Composition) In one embodiment, the present invention is a sputtering target composed of a sintered body containing a binary alloy of Cu and Al, with the balance consisting of inevitable impurities. The sputtering target may include a backing plate, and in addition to this, may include a bonding layer.

[0019] The shape of the sputtering target is not particularly limited, but may typically be a flat plate shape (for example, circular, rectangular, etc.).

[0020] In the sputtering target, the contents (at%) of Cu and Al satisfy the relational expression of 0.48 ≤ Al / (Cu + Al) ≤ 0.70.

[0021] By setting the content ratio of Al to be 48 at% or more and 70 at% or less with respect to the total content of Cu and Al, a conductor composed of an intermetallic compound of Cu and Al can be favorably formed. This conductor can be expected to have characteristics such as excellent conductivity and adhesion between the conductor and the insulator. From this perspective, with respect to the total content of Cu and Al, the content ratio of Al is preferably 50 at% or more, more preferably 55 at% or more, even more preferably 62 at% or more, and even more preferably 66 at% or more.

[0022] Also, from the same perspective, with respect to the total content of Cu and Al, the content ratio of Al is preferably 69 at% or less, and more preferably 68 at% or less.

[0023] The sputtering target preferably contains an intermetallic compound of CuAl2 and / or CuAl, and even more preferably, the sputtering target is an intermetallic compound of CuAl2 and / or CuAl. That is, it is even more preferable that the content of Cu and Al is Al / (Cu + Al) = 0.67 ± 0.02, or Al / (Cu + Al) = 0.50 ± 0.02, and even more preferably Al / (Cu + Al) = 0.67 ± 0.01, or Al / (Cu + Al) = 0.50 ± 0.01, and it is even more preferable that the content of Cu and Al is Al / (Cu + Al) = 0.67, or Al / (Cu + Al) = 0.50.

[0024] If a target material of an intermetallic compound of CuAl2 or CuAl can be produced, there is no need to separately produce pure metal targets of Cu and Al for forming a CuAl2 wiring material or a CuAl wiring material, and there is also less risk of impurities being mixed in during sputtering. Therefore, the purity of the sputtering target of the present embodiment is preferably 4N (99.99 mass%) or more, more preferably 4N5 (99.995 mass%) or more, and even more preferably 5N (99.999 mass%) or more.

[0025] Here, the purity of the sputtering target being 4N (99.99 mass%) or higher means that when the composition is analyzed by glow discharge mass spectrometry (GDMS), the total amount of Na, P, S, K, Ca, Cr, Fe, Ni, As, Ag, Sb, Bi, Th, and U contained in the sputtering target is less than 0.01 mass% (100 mass ppm).

[0026] In addition, when manufacturing a sputtering target from an ingot composed of an intermetallic compound of Cu and Al as described later, the contents of Cu and Al can be the contents of Cu and Al in the ingot. When measuring from the product sputtering target, the composition of the sputtering target can be measured by inductively coupled plasma optical emission spectrometry (ICP - OES).

[0027] The oxygen content of the sputtering target is not particularly limited, but from the manufacturing process, 50 mass ppm or more is inevitable, and 1500 mass ppm or less is preferable. Typically, the lower limit of the oxygen content may be 200 mass ppm or more, or 500 mass ppm or more, and the upper limit of the oxygen content may be 1000 mass ppm or less. The oxygen content of the sputtering target is measured by an inert gas fusion - infrared absorption method (for example, TCH600 manufactured by LECO).

[0028] (2. Relative density) In one embodiment, the sputtering target of the present invention has a relative density of 95% or higher. By increasing the relative density of the target, the occurrence of cracks during processing or sputtering of the sputtering target can be suppressed. Also, a higher relative density of the target is preferable for performing stable sputtering with less arcing. The relative density is preferably 97% or higher, more preferably 98% or higher, and even more preferably 99% or higher. There is no particular upper limit for the relative density, but for example, it can be 100% or less, or 99.9% or less, or 99.5% or less, or 99.0% or less.

[0029] The relative density is calculated by the formula: relative density = measured density ÷ theoretical density × 100 (%). Here, the measured density is the value obtained by dividing the weight by the volume, and the volume is measured by the Archimedes method. The theoretical density is calculated by weighted average assuming that the entire sputtering target consists of CuAl2 (θ phase) and CuAl (η phase), with the theoretical density of CuAl2 (θ phase) being 4.35 g / cm 3 and the theoretical density of CuAl (η phase) being 5.36 g / cm 3 . Note that the ratios of CuAl2 (θ phase) and CuAl (η phase) are calculated from the composition of the sputtering target. The relative density calculated using this theoretical density may exceed 100%.

[0030] From the perspective of suppressing crack generation during the processing or sputtering of the sputtering target, a higher relative density is desirable. However, simply melting Cu and Al, or a Cu - Al alloy and casting an ingot, even if the relative density can be increased, is prone to cracking during cutting or fixing, making it difficult to obtain a sputtering target as a product. As will be described later, the present invention can first realize a Cu - Al binary alloy sputtering target with a high relative density and low crack susceptibility by producing atomized powder and sintering this atomized powder and the like under predetermined conditions.

[0031] (3. Composition uniformity) In one embodiment of the present invention, when the Al content at a total of five points including the center position, the outer peripheral position, and the intermediate position in the middle of the sputtering surface of a flat sputtering target, which extend from the center to the outer periphery of the sputtering surface and are arranged on two straight lines perpendicular to each other, is measured by ICP-OES, the difference between the maximum value and the minimum value of each content is preferably 0.2 at% or less. Here, the outer peripheral position is a position that is 1 / 8 of the length from the center to the outermost periphery in the direction from the outermost periphery of the sputtering target toward the center. The intermediate position in the middle between the center position and the outer peripheral position is a position at the center point of the straight line connecting the center position and the outer peripheral position. In this way, since the difference in the Al content at the measurement points is small and the compositional uniformity is high, the composition of the sputtering target becomes uniform at each location, which is useful for forming a uniform conductive layer.

[0032] From this perspective, it is more preferable that the difference between the maximum value and the minimum value of the Al content measured based on the above method is 0.1 at% or less. This compositional uniformity cannot be achieved, for example, in a sputtering target in which single Cu and single Al are alternately arranged or mixed, but it is possible to achieve a high level of homogenization by producing atomized powder as described later.

[0033] Here, referring to FIG. 1 for explanation, when the sputtering surface of the sputtering target is circular, its center A is the center of the circle, and the five points of the center position A, the outer peripheral positions E and C, and the intermediate positions B and D in the middle are arranged in an L shape. The outer peripheral positions E and C are positions that are 1 / 8 of the length from the center A to the outermost periphery in the direction from the outermost periphery of the sputtering target toward the center A. When the sputtering surface of the sputtering target is rectangular, its center is the intersection of the diagonals.

[0034] (4. Crystal Structure) The crystal structure of the sputtering target can be specified by analyzing it with an XRD (X-ray diffractometer) with respect to the sputtering surface. The mass ratio of each crystal phase can be obtained by performing quantitative analysis using the RIR (Reference Intensity Ratio) method on the results of the XRD analysis. Here, the RIR method is a method for obtaining the mass ratio of a crystal phase from the ratio of the RIR value and the value of the strongest peak intensity of each crystal phase obtained from the results of XRD. When crystal phases A, B, C, ··· are included in the sputtering target, the mass ratio X A is calculated by the following formula. X A =I A k A / (I A k A +I B k B +I C k C +···) Here, I represents the intensity of the strongest peak of the X-ray of each crystal phase, and k represents the RIR value of each crystal phase. As the RIR value, the value described in the powder diffraction file (PDF) database of the International Center for Diffraction Data can be used. By performing quantitative analysis using the RIR method, quantitative values of each phase of Cu, Al, CuAl2, and CuAl can be obtained. Therefore, the mass ratio of the total value of CuAl2 + CuAl can also be obtained.

[0035] The mass ratio of the total value of CuAl2 + CuAl is preferably 95% or more, more preferably 98% or more. Thereby, a conductor made of an intermetallic compound of Cu and Al can be favorably formed. Further, when CuAl2 is the main phase, the mass ratio of CuAl2 is preferably 70% or more, more preferably 90% or more, and even more preferably 95% or more. Here, the main phase means the most abundant crystal phase among the crystal phases contained in the sputtering target. When CuAl is the main phase, the mass ratio of CuAl is preferably 70% or more, more preferably 90% or more, and even more preferably 95% or more. Thereby, a conductor made of an intermetallic compound of Cu and Al can be favorably formed. Furthermore, in a preferred embodiment of the present invention, the mass ratio of the total value of CuAl2 + CuAl is 100%, that is, no Cu single phase or Al single phase is included.

[0036] (5. Manufacturing method) If the sputtering target of the present invention is composed of a sintered body, the specific manufacturing method is not limited, but the manufacturing method in one embodiment includes at least the following steps. · A step of producing atomized powder, and · A step of sintering at least one of the atomized powder and the powder derived therefrom by hot pressing at a temperature of 550°C or higher.

[0037] More preferably, an ingot may be produced so that the contents of Cu and Al (at%) satisfy the relational expression of 0.48 ≤ Al / (Cu + Al) ≤ 0.70, and atomized powder may be produced from the ingot. Further, the atomized powder may be further pulverized, and after the pulverization, it may be sintered by hot pressing.

[0038] Hereinafter, each step will be described in detail.

[0039] Step 5-1 of producing an ingot As described below, it is not always necessary to prepare an ingot as long as atomized powder that is a raw material for a Cu-Al binary alloy can be produced. However, in some embodiments of the present invention, it is preferable to prepare an ingot by melting desired Cu and Al or melting a desired Cu-Al alloy so that the content (at%) of Cu and Al satisfies the relational expression of 0.48 ≦ Al / (Cu + Al) ≦ 0.70. In that case, the material to be melted can be selected according to the above-described final target components. For example, when the target component is CuAl2, a CuAl2 alloy may be melted, or Cu and Al may be charged and melted so that the atomic ratio of Cu and Al becomes 1:2. By melting and preparing an ingot, the raw materials can be stirred once to promote homogenization.

[0040] The melting temperature is not particularly limited, but is preferably 800 to 1000 °C, and more preferably 850 to 950 °C.

[0041] The molten metal can be poured into a mold to produce a desired ingot.

[0042] Step 5-2 of producing atomized powder from the ingot Atomization treatment can be performed on the obtained ingot to obtain atomized powder. Although it is preferable to use the above ingot as a raw material, there is no particular limitation as long as atomized powder having a desired atomic ratio of Cu and Al can be produced. For example, when the target component is CuAl2, Cu and Al may be charged into an atomization device and melted so that the atomic ratio becomes 1:2 to produce atomized powder. By making powder by atomization treatment, it can be used for hot pressing in a subsequent process, and the target can be manufactured. Further, by producing atomized powder, homogenization of the material can be promoted.

[0043] Atomization processes include disk atomization, water atomization, gas atomization, etc., among which gas atomization is preferred. The conditions for gas atomization are not particularly limited, but the temperature of the atomization process is preferably 700 to 900 °C, more preferably 750 to 850 °C. The gas pressure is also not particularly limited, but 1 to 10 MPa is preferred, and 3 to 7 MPa is more preferred.

[0044] Step 5-3 of pulverizing the atomized powder The atomized powder may then be subjected to hot pressing to form a sintered body. In another embodiment, the atomized powder may be further pulverized and then subjected to hot pressing. This can improve the relative density of the target. And by improving the relative density, the sputtering characteristics can be improved.

[0045] The means for pulverization is not particularly limited, but a known mechanical pulverizer can be used (for example, a tabletop impact pulverizer (for example, SP Mill manufactured by NWLaboratory)).

[0046] The particle size of the atomized powder or the powder obtained by pulverizing the atomized powder (particle size D50 at 50% cumulative frequency based on volume in the measurement of particle size distribution by laser diffraction method) is preferably adjusted to be about 35 μm to 45 μm. If the step of pulverizing the atomized powder is not carried out, the particle size of the atomized powder may be larger than the above range, for example, 45 μm to 100 μm.

[0047] Step 5-4 of hot pressing The atomized powder or the powder obtained by pulverizing the atomized powder is put into a hot press container, and a sintered body can be obtained by performing hot pressing. As the conditions for hot pressing, it is carried out at at least 550 °C or higher. By performing it at 550 °C or higher, the workability is improved (for example, the possibility of cracking during manufacturing can be reduced). Also, by performing it at 550 °C or higher, the relative density is also improved. The upper limit of the temperature is not particularly limited, but it is 700 °C or lower, typically 600 °C or lower. More preferably, it is 560 - 580 °C.

[0048] The pressure is not particularly limited, but 200 - 450 kgf / cm 2 is preferable, and 250 - 350 kgf / cm 2 is more preferable. Also, the holding time is not particularly limited, but 3 - 8 hours is preferable, and 5 - 6 hours is more preferable.

[0049] Step 5-5 of other processes After a sintered body is obtained by hot pressing, other processing treatments may be appropriately performed. For example, hot isostatic pressing may be performed to further improve the relative density. Also, in order to finish the sintered body into the shape of a product for shipment, machining such as grinding and / or cutting may be appropriately performed. And the sintered body may be bonded to a backing plate to finish the final product. The conditions for these other processes are not particularly limited, and conditions known in the art may be appropriately adopted.

[0050] Note that, as described above, in the above manufacturing method, since the powder is sintered, it may not include a rolling process and a forging process.

[0051] The sputtering target according to one embodiment of the present invention is excellent in workability and has little possibility of cracking with respect to processing during manufacturing (for example, grinding, cutting, etc.). Also, since the relative density is relatively high, wetting with grinding oil or the like can be avoided. Also, since it is manufactured as a sintered body, it is not necessary to perform a rolling process and a forging process, and the possibility of cracking caused by these rolling and forging processes can be eliminated.

[0052] Furthermore, the sputtering target according to an embodiment of the present invention is also excellent in material uniformity. For example, there are few irregularities in appearance (e.g., color irregularities). For example, when observing the structure by means such as SEM, there are few shading differences depending on the observation location.

Examples

[0053] Hereinafter, the present invention will be specifically described by way of examples. However, the description here is for illustrative purposes only and is not intended to be limiting.

[0054] (Examples 1 to 3, Comparative Examples 1, 2) An ingot was produced by melting a CuAl2 intermetallic compound with a composition of Al 66.7 at% ± 0.5 at% and the balance being Cu and inevitable impurities (900 °C). Next, atomization treatment (gas atomization) was performed on the ingots of Examples 1 to 3 and Comparative Example 2. The temperature of the atomization treatment was 780 °C and the gas pressure was 5 MPa. In some examples (Example 1), the obtained atomized powder was further pulverized by an SP mill. The D50 of the particles before pulverization was 75 μm, and the D50 of the particles after pulverization was 40 μm. However, for Comparative Example 1, after producing the ingot, attempts were made to produce a sputtering target by rolling and forging without performing atomization treatment or the like.

[0055] (Example 4) An ingot was produced by melting an intermetallic compound of Cu and Al with a composition of Al 62.7 at% ± 0.5 at% and the balance being Cu and inevitable impurities (900 °C). Next, atomization treatment (gas atomization) was performed on the ingot. The temperature of the atomization treatment was 780 °C and the gas pressure was 5 MPa.

[0056] (Example 5) An ingot was produced by melting a CuAl intermetallic compound with a composition of Al 50 at% ± 0.5 at% and the balance being Cu and inevitable impurities (at 900 °C). Next, atomization treatment (gas atomization) was performed on the ingot. The temperature of the atomization treatment was 780 °C and the gas pressure was 5 MPa.

[0057] The obtained powder was hot-pressed under the conditions of a temperature of 570 °C (550 °C, 555 °C in some examples and 525 °C in some comparative examples), 250 - 350 kgf / cm 2 , and a holding time of 5 - 6 hours to obtain a circular sintered body with a thickness of 16 - 17 mm and a diameter of 460 mm. Finally, each sintered body was processed by cutting, grinding, etc. The presence or absence of cracks was confirmed at that time.

[0058] The relative density of the obtained sintered body was measured as described above. As the theoretical density, except for Examples 4 and 5, the values obtained by weighted averaging with the ratios of CuAl2 (θ phase) and CuAl (η phase) being 97.5 vol% and 2.5 vol% respectively (4.38 g / cm 3 ) were used. In Example 4, the theoretical density was 4.39 g / cm 3 , and in Example 5, the relative density was measured in the same manner except that the theoretical density of CuAl (η phase) of 5.36 g / cm 3 was used.

[0059] Also, the purity and oxygen content of the sintered body were measured as described above. Note that for Comparative Examples 1 and 2, the workability was poor and they could not be used as sputtering targets, so the measurement of purity and oxygen content was not performed.

[0060] Also, in the sintered compacts of Example 2 and Example 5, about 10 g of samples were cut out from each of the five points A to E shown in FIG. 1 as described above. Then, the Al content of each sample was measured by ICP-OES (manufactured by Agilent Technologies, Agilent 5110 ICP-OES). Specifically, assuming that point A is the center position, points B and D are the intermediate positions, and points C and E are the outer peripheral positions, care was taken to cut out only the samples within 5 mm centered on these points when cutting out the samples. When calculating the difference between the maximum value and the minimum value of each content, it was 0.1 at% in Example 2 and Example 5.

[0061] Also, the sputter surfaces of the sintered compacts of Example 2, Example 4, and Example 5 were analyzed by an X-ray diffractometer (manufactured by Rigaku, model MiniFlex600), and the RIR (Reference Intensity Ratio) method was applied to quantify CuAl2 (θ phase) and CuAl (η phase). The calculation method was obtained by dividing the value obtained by multiplying the integrated intensity of the strongest peak of each phase in the diffraction pattern obtained by the X-ray diffractometer by the RIR value by the sum of the values obtained by multiplying the integrated intensity of the strongest peak of each phase by the RIR value. As the RIR values, the values described in the powder diffraction file (PDF) database of the International Center for Diffraction Data were used (ICSD Nos. 01-071-5027 and 03-065-1228). Specifically, 2.74 (No. 01-071-5027) was used as the RIR value of CuAl2 (θ phase), and 2.06 (No. 03-065-1228) was used as the RIR value of CuAl (η phase). The analysis conditions were set as follows. · X-ray source: CuKα ray · Measurement range: 2θ = 10° to 90° · Step: 0.01° · Scan speed: 20.0° / min · Detector: High-speed one-dimensional detector D / teX Ultra · Tube voltage: 40 kV · Tube current: 30 mA

[0062] The manufacturing conditions and evaluation contents of each example and comparative example are shown in Tables 1 to 3.

[0063]

Table 1

[0064]

Table 2

[0065]

Table 3

[0066] In Examples 1 to 5, no cracking occurred, and the target could be manufactured as a product. Moreover, the relative density was 95% or more. Furthermore, the sputtering target of the present invention was resistant to repeated heating and cooling, and cracking was less likely to occur during sputtering. Also, from the analysis of the compositions of Examples 2 and 5, the Al content was almost the same at each measurement location, and although not shown in Table 2, the remainder at each measurement location was found to be Cu. That is, it was found that the sputtering target of the present invention had good uniformity in the composition of Cu and Al. Note that, as shown in Table 2, the elemental composition ratio of the finally produced sputtering target may slightly differ from the composition ratio of the raw materials.

[0067] Comparative Example 1 is an example in which, after melting to produce an ingot, an attempt was made to produce it by rolling and forging. Cracking occurred during the cutting and fixing of the ingot before reaching rolling and forging.

[0068] In Comparative Example 2, atomized powder was produced after melting to produce an ingot under the same conditions as in Examples 2 to 3. However, since the hot press temperature was too low, cracking and wetting by grinding oil occurred during the final product finishing processes (cutting, grinding).

[0069] In Example 1, after producing atomized powder, further grinding was performed, so the relative density in the final product was improved compared to Example 2.

[0070] Furthermore, as can be seen from Table 3, the intermetallic compound of Cu and Al can be formed without problems in the present invention. Also, in Examples 2 and 4, since a large amount of CuAl2 (θ phase) can be formed, it is considered advantageous for forming a sputter film with a relatively uniform CuAl2 composition. In Example 5, since a large amount of CuAl (η phase) can be formed, it is considered advantageous for forming a sputter film with a relatively uniform CuAl composition. As shown in Table 3, in these examples, the mass ratio of the total value of CuAl2 + CuAl is 100%, that is, there is no Cu single phase or Al single phase.

[0071] As described above, specific embodiments of the present invention have been described. Each of the above embodiments is merely a specific example of the present invention, and the present invention is not limited to these embodiments. For example, the technical features disclosed in one of the above embodiments can be applied to other embodiments.

Claims

1. A sputtering target composed of a sintered body containing a binary alloy of Cu and Al, with the balance consisting of inevitable impurities, wherein the content (at%) of Cu and Al satisfies the relational expression of 0.48 ≦ Al / (Cu + Al) ≦ 0.70, and the relative density is 95% or more.

2. When the content of Al at a total of 5 points including the center position, outer peripheral position, and intermediate positions in the middle of the sputtering surface of the sputtering target, which extend from the center to the outer periphery of the sputtering surface and are arranged on two straight lines perpendicular to each other, is measured by inductively coupled plasma optical emission spectrometry, the difference between the maximum value and the minimum value of each content is 0.2 at% or less. The sputtering target according to Claim 1.

3. When analyzed with an X-ray diffractometer and quantitatively analyzed using the RIR (Reference Intensity Ratio) method for the results, CuAl 2 The sputtering target according to claim 1 or 2, wherein the mass ratio of the total value of CuAl and CuAl is 95% or more.

4. The binary alloy of Cu and Al is CuAl 2 The sputtering target according to any one of claims 1 to 3, comprising an intermetallic compound of CuAl and / or CuAl

5. The sputtering target according to any one of Claims 1 to 4, wherein the oxygen content is 50 to 1000 mass ppm.

6. A method for manufacturing a sputtering target composed of a sintered body containing a binary alloy of Cu and Al, with the balance consisting of inevitable impurities, wherein the content (at%) of Cu and Al in the sintered body satisfies the relational expression of 0.48 ≦ Al / (Cu + Al) ≦ 0.70, the method includes a step of producing atomized powder, and a step of sintering at least one of the atomized powder and the powder derived therefrom by hot pressing at a temperature of 550°C or higher.

7. Before producing the atomized powder, the method further includes a step of producing an ingot such that the content (at%) of Cu and Al satisfies the relational expression of 0.48 ≦ Al / (Cu + Al) ≦ 0.70, and producing the atomized powder from the ingot. The method according to Claim 6.

8. The method according to Claim 6 or 7, further including a step of further pulverizing the atomized powder before sintering.

9. The binary alloy of Cu and Al is CuAl 2 The method according to any one of claims 6 to 8, comprising an intermetallic compound of CuAl and / or CuAl.

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