Sputtering target assembly and film

Abstract

Provided is a tungsten sputtering target assembly having improved peel strength. In one example, the invention provides the following invention. A sputtering target assembly is a sputtering target assembly provided with a target, a backing plate, and an insert, the target is composed of W, the backing plate contains Ti or a Ti alloy, the insert contains Cu or a Cu alloy, and the average particle diameter of the target is 20 μm or more.

Description

Technical Field

[0001] This invention relates to a sputtering target assembly and a film. Specifically, this invention relates to a tungsten sputtering target assembly and a film prepared using the same. Background Technology

[0002] In recent years, low resistivity has become a requirement in electrode and wiring materials. Tungsten is being considered as a material to meet this requirement.

[0003] Patent Document 1 discloses a tungsten sputtering target capable of forming a tungsten film with low resistivity. Specifically, Patent Document 1 discloses a tungsten sputtering target with an average particle size exceeding 100 μm in order to obtain a tungsten film with low resistivity.

[0004] Patent Document 2 discloses a sputtering target assembly. In this sputtering target assembly, the target and backing plate are joined by an insert. Furthermore, it discloses the principle that metals such as W, Mo, Ti, Ta, Zr, Nb, Al, and Ti, and their alloys, can be used as target materials. Moreover, it discloses the principle that Al, Ag, Cu, Ni, or their alloys can be used as inserts. Furthermore, it discloses the principle that Al and Al alloys, OFC (oxygen-free copper), Cu alloys, Ti, Ti alloys, and SUS (stainless steel) can be used as backing plates.

[0005] [Previous Technical Documents] [Patent Literature] [Patent Document 1]: Japanese Patent Application Publication No. 2019-090071 [Patent Document 2]: Japanese Patent Application Publication No. 2000-239837. Summary of the Invention

[0006] In sputtering target assemblies, it is important to ensure the peel strength between the target and the backing plate. This is especially true in tungsten sputtering target assemblies, where there is room for improvement in the peel strength between the target and the backing plate.

[0007] The purpose of this invention is to provide a tungsten sputtering target assembly with improved peel strength.

[0008] To achieve the above objectives, in one example, the present invention includes the following invention.

[0009] (Invention 1) A sputtering target assembly comprising a target, a backplate, and an insert. The target is composed of W. The backplate contains Ti or a Ti alloy. The insert contains Cu or a Cu alloy. The average particle size of the target is over 20 μm.

[0010] (Invention 2) As in the sputtering target assembly of Invention 1, the target is circular. The lowest peel strength measured at four points in the outer peripheral region of the target and the backplate was 6 kgf / mm². 2 above.

[0011] (Invention 3) As in the sputtering target assembly of Invention 2, the average peel strength of 10 points across the entire region of the target and the backplate, as measured, is 6 kgf / mm². 2 above.

[0012] (Invention 4) The sputtering target assembly described in any one of inventions 1 to 3, wherein the mating surface of the target is free of machining marks.

[0013] (Invention 5) The sputtering target assembly described in any one of inventions 1 to 4, wherein the insert is composed of Cu and unavoidable impurities, and the purity of Cu is 99.9% by mass or more.

[0014] (Invention 6) The sputtering target assembly described in any one of inventions 1 to 5, wherein the insert is composed of Cu and unavoidable impurities, and the oxygen content is less than 10 ppm by mass.

[0015] (Invention 7) A film made using the sputtering target assembly described in any one of inventions 1 to 6.

[0016] In one example, in the invention described above, the insert contains Cu or a Cu alloy. This improves the peel strength between the target and the backing plate. Attached Figure Description

[0017] [ Figure 1 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0018] [ Figure 2 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0019] [ Figure 3 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0020] [ Figure 4 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0021] [ Figure 5[] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0022] [ Figure 6 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0023] [ Figure 7 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0024] [ Figure 8 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment.

[0025] [ Figure 9 [] indicates the location where the peel strength is measured in a sputtering target assembly of one embodiment. Detailed Implementation

[0026] The following describes specific embodiments for carrying out the invention. This description is intended to facilitate understanding of the invention and is not intended to limit the scope of the invention.

[0027] 1. Sputtering target assembly In one embodiment, the present invention relates to a sputtering target assembly. The sputtering target assembly includes at least a target, a backplate, and an insert.

[0028] 1-1. Target (shape) The shape of the target is not particularly limited, but it is typically a flat plate. Preferably, the shape of the target when viewed from above is either rectangular (e.g., square, rectangle, etc.) or circular, and more preferably circular.

[0029] (composition) The target is made of tungsten (W).

[0030] (Impurities) However, the target may contain unavoidable impurities in addition to tungsten. The types of unavoidable impurities are not particularly limited; for example, they may be one or more selected from the group consisting of carbon and oxygen. The upper limit of the amount of unavoidable impurities is not particularly limited; for example, it may be 50 ppm by mass or less, preferably 30 ppm by mass or less, more preferably 20 ppm by mass or less, and most preferably 10 ppm by mass or less. Preferably, the oxygen content in the unavoidable impurities is 10 ppm by mass or less. The lower limit of the amount of unavoidable impurities is not particularly limited; for example, it may be 0 ppm by mass or more, typically 1 ppm by mass or more.

[0031] By suppressing the amount of unavoidable impurities (especially carbon and oxygen), the effect of impurities on the resistivity of the tungsten film is reduced.

[0032] There are no particular limitations on the methods for determining unavoidable impurities; well-known methods in the field can be implemented. For example, carbon concentration can be determined by preparing a sample from the target or from a material of the same origin as the target (e.g., scrap material), and then using a carbon analysis apparatus [LECO, CSLS600] with an inactive gas fusion method. Similarly, oxygen concentration can be determined by preparing a sample from the target or from a material of the same origin as the target (e.g., scrap material), and then using an oxygen-nitrogen simultaneous analysis apparatus [LECO, TC-600] with an inactive gas fusion method.

[0033] (purity) As described above, the target is made of tungsten. The purity of the target is not particularly limited, but can be 99.999% by mass (5N) or higher, preferably 99.9999% by mass (6N) or higher. By achieving high purity, a tungsten film with low resistivity can be formed.

[0034] (Surface shape) When the target is flat, it has two surfaces. The first surface is the side to be sputtered, and the second surface is the bonding surface, i.e., the back plate side. The surface shape of the second surface is not particularly limited.

[0035] In a preferred embodiment, the second surface is free of machining marks. Furthermore, in this specification, the term "free of machining marks" means that there are no recesses, and / or even if recesses exist, their depth is less than 0.05 mm. The depth value of the recess can be, for example, a value measured by a depth gauge. Moreover, the location for depth measurement is not particularly limited; for example, a straight line of a specific length (e.g., 5 cm) can be drawn at any point on the surface, and the observed recesses can be measured along this line. Furthermore, when multiple recesses exist along the straight line, the average depth of each recess can be calculated.

[0036] (Relative density) The relative density of the target is not particularly limited, but can be, for example, 99.2% or higher. This is because a lower gas content in the target reduces the resistivity of the film during formation. Furthermore, it also suppresses dust generation caused by abnormal discharge. The relative density of the target is preferably 99.5% or higher, more preferably 99.7% or higher, and even more preferably 99.9% or higher.

[0037] The relative density described in this specification refers to the ratio of measured density to theoretical density. Measured density refers to the value obtained using the Archimedes method with pure water as the solvent. The theoretical density is the theoretical density when the tungsten content is 100%.

[0038] 1-2. Back panel The backplate contains Ti or a Ti alloy. In a preferred embodiment, the backplate is made of Ti or a Ti alloy. When the backplate contains Ti or is made of Ti, the term "Ti" refers to pure Ti. However, the Ti in the backplate may also contain unavoidable impurities (e.g., 2N5 or higher).

[0039] Ti and Ti alloys can help prevent cracking by reducing warping during diffusion bonding with the target.

[0040] Furthermore, specific examples of Ti alloys include Ti-6Al-4V, etc. Additionally, the upper limit of the coefficient of thermal expansion of Ti alloys is preferably 11 × 10⁻⁶. -6 Below / ℃, and preferably 9×10 -6 / ℃ or below. The above upper limit range is also suitable for the thermal expansion coefficient of backplates containing Ti or Ti alloys.

[0041] 1-3. Embedded objects The insert is located between the target and the backplate, serving to bond materials that cannot be joined by the target and backplate alone, preventing breakage, etc. In one embodiment, the insert contains Cu or a Cu alloy. In a preferred embodiment, the insert is made of Cu or a Cu alloy. Cu or Cu alloys are suitable for promoting the bonding of a tungsten target to a backplate containing Ti or a Ti alloy. Furthermore, Cu or Cu alloys are metals with relatively high melting points. Therefore, the bonding of the target and backplate can be performed at higher temperatures (e.g., pressing). Moreover, by performing the process at higher temperatures, the peel strength between the target and the backplate is improved.

[0042] Furthermore, there are no particular limitations on the inlay containing Cu or Cu alloys. For example, the Cu content in the Cu alloy or the Cu content in the inlay is preferably 80% by mass or more, and more preferably 90% by mass or more. The melting point of the Cu or Cu alloy used in the inlay, or the melting point of the inlay containing them, is 1000°C to 1200°C. In addition, specific examples of Cu alloys include, for example, red brass (e.g., JIS H 3100, C2100, JIS H 3100, C2200, etc.).

[0043] Preferably, the insert is made of Cu. However, the insert may contain unavoidable impurities in addition to Cu.

[0044] The purity of Cu in the insert is preferably high. For example, the purity of Cu can be 99.9% by mass or more, preferably 99.90% by mass or more, more preferably 99.95% by mass or more, and most preferably 99.99% by mass or more.

[0045] Cu, for example, includes the following: tough copper, oxygen-free copper, etc. Among them, oxygen-free copper is preferred. Oxygen-free copper may be, for example, a specific Cu according to Japanese Industrial Standards, namely JIS H 3100, C1020, JIS H 3510, or C1011. Alternatively, oxygen-free copper may be, for example, a specific Cu in the UNS (unified numbering system) database, namely C10100, C10200, or C11000.

[0046] Increasing purity can improve the peel strength between the target and the backing plate. In a particularly preferred example, reducing the amount of oxygen as an impurity can improve the peel strength between the target and the backing plate.

[0047] When the intercalation is composed of Cu, the upper limit of the oxygen content, which is an unavoidable impurity, can be 100 ppm by mass or less, preferably 10 ppm by mass or less. The lower limit of the oxygen content is not particularly limited; for example, it can be 0 ppm by mass or more, typically 1 ppm by mass or more. The oxygen concentration can be determined by preparing a sample from the intercalation and then using an oxygen-nitrogen simultaneous analysis apparatus [LECO, TC-600] on the sample, employing the inactive gas melting method.

[0048] 1-4. Target particle size As described above, the target is made of tungsten. Here, the average grain size of the tungsten crystals is 20 μm or more. By having an average grain size of at least a specified value, the resistivity can be sufficiently reduced during film formation. For reasons that significantly lower resistivity is sometimes required in the semiconductor field, the lower limit of the average grain size of the tungsten crystals is preferably 30 μm or more, more preferably 40 μm or more, and most preferably 100 μm or more. The upper limit of the average grain size is not particularly limited, and for example, it can be 300 μm or less.

[0049] In this specification, the average grain size of tungsten crystals refers to the value measured based on the cutting method of JIS G 0551:2013. Specifically, the average grain size of tungsten crystals refers to the value obtained according to the following procedure: • The target surface was etched using a 0.5 mol / L sodium hydroxide aqueous solution.

[0050] • Use an optical microscope to observe the tissue on the target surface and save the tissue image data.

[0051] • Draw three parallel straight lines in the tissue image. Furthermore, the length of each line is not particularly limited, but is preferably a length containing at least 10 or more crystal particles.

[0052] • Calculate L / N using the number of particles (N) on each straight line and the total length of the line (L), and take the average of the calculation results as the average particle size of the observed part.

[0053] 1-5. Peel strength of sputtering target assembly In one embodiment of the present invention, the sputtering target assembly exhibits high peel strength between the target and the backing plate.

[0054] In the case of target-backplate bonding, high bonding strength in the peripheral region is particularly important. The reasons for this include: the area of ​​the peripheral region is larger than that of the central region, and the higher bonding strength in the larger area greatly contributes to improving the bonding strength between the target and the backplate.

[0055] From this perspective, in one embodiment of the invention, the minimum peel strength measured at four points in the peripheral region of the target and backing plate can be 6 kgf / mm². 2 above.

[0056] The four points to be measured are determined according to the following procedure when the target is circular.

[0057] (A) such as Figure 1 As shown, draw two mutually orthogonal straight lines (the first line and the second line) that pass through the center of the circle.

[0058] (B) such as Figure 2 As shown, on the first straight line, a specific distance from the center of the circle ( Figure 1 The point at a distance of 8R / 10 from the circle (where R is the radius).

[0059] (C) such as Figure 2 As shown, draw a perpendicular line (the third line) from that point that is orthogonal to the first line.

[0060] (D) such as Figure 2 As shown, from the intersection of the first line and the third line, two points (the first measurement point and the second measurement point) are identified along the third line as 1R / 10.

[0061] (E) On the second straight line, the same procedure as (B) to (D) above is performed to identify two points (the third measurement site and the fourth measurement site) that are 1R / 10.

[0062] like Figure 3 As shown, in the case of a rectangle, the distance from the center to the vertex can be considered as the radius R of the circular pattern described above, and procedures (A) to (E) can be performed accordingly. Alternatively, as... Figure 4 As shown, in the case of a rectangle, the distance from the center to each side can be considered as the radius R of the circular pattern described above, and the procedures (A) to (E) described above can be performed. Furthermore, test pieces can be collected from these measurement locations, and tensile tests can be performed on each test piece, using the minimum strength.

[0063] In one embodiment, the minimum peel strength measured at four points in the outer peripheral region of the target and backing plate of the present invention, as described above, can be 6 kgf / mm². 2 The above is preferably 8 kgf / mm 2 That's all. There's no specific upper limit; it can be 10 kgf / mm. 2 the following.

[0064] In another embodiment, when the target and backplate are joined, it is preferable that the joining strength is high not only in the outer peripheral region but also throughout the entire region.

[0065] From this perspective, the average peel strength measured at 10 points across the entire area of ​​the target and backing plate can be 6 kgf / mm². 2 The above is preferably 8 kgf / mm 2 That's all. There is no specific upper limit; it can be 12 kgf / mm. 2 the following.

[0066] The 10 points used for measurement are set up in a circular pattern as follows (refer to...). Figure 5 and Figure 6 ).

[0067] (a) Perform the procedures for the above-mentioned four specific measurement objects (measurement sites 1 to 4).

[0068] (b) Change “8R / 10” to “5R / 10” in the procedure (A) to (E) for the four specific measurement objects mentioned above and implement it (for measurement sites 5 to 8).

[0069] (c) Change “8R / 10” to “1R / 10” in the procedure (A) to (D) for the two specific measurement objects mentioned above and implement it (measurement sites 9 to 10).

[0070] On the other hand, in the case of rectangles, such as squares, as Figure 7 As shown, the distance from the center to the vertex can be considered as the radius R of the circular pattern described above, and the procedures described in (a) to (c) can be performed accordingly. Alternatively, in the case of a rectangle, such as a square, as... Figure 8 As shown, the distance from the center to each side can be considered as the radius R of the circular pattern described above, and procedures (a) to (c) can be performed accordingly. Furthermore, test pieces can be collected from these measurement locations, and tensile tests can be performed on each piece, with the average strength used. Moreover, when the target is rectangular, procedure (c) can be performed on either the long or short side. Typically, procedure (c) is performed on the long side (see...). Figure 9 ).

[0071] The tensile test shall be performed as follows.

[0072] • Prepare a test specimen of a laminate consisting of a target, insert, and backing plate, and determine the maximum load (kgf) for target and backing plate peeling. The test speed is set to 0.5 mm / min.

[0073] • Divide the measured maximum load by the bonding area (mm²) 2 ).

[0074] There are no particular limitations on the machine used for tensile testing. For example, tensile test specimens with a diameter of 6 mm can be made, and the peel strength can be measured using an Autograph AG-100kNX plus precision universal testing machine manufactured by Shimadzu Corporation. Furthermore, the tensile test specimens are made in a manner that includes the target, insert, and backing plate, and that each mating surface is parallel to the surface of the tensile test specimen.

[0075] The target of the present invention in one embodiment has the aforementioned peel strength, a feature that is particularly useful when the target particle size is large (e.g., an average particle size of 40 μm or more, preferably 100 μm or more). While a large target particle size offers the advantage of lower electrical resistance, it also tends to result in lower target strength and a higher likelihood of breakage. Methods to reduce breakage include eliminating stress concentration points. However, a shape without stress concentration points results in a reduction in the bonding strength between the target and the backing plate. The target of the present invention in one embodiment helps to avoid or compensate for this reduction in bonding strength.

[0076] 2. Manufacturing method In one embodiment, the present invention relates to a method for manufacturing the above-described sputtering target assembly.

[0077] The above method may include, for example, the following steps.

[0078] • Steps for providing the target, insert, and backplate • The steps of sequentially stacking the target, insert, and backing plate from top to bottom and performing HIP (hot isostatic pressing) bonding. The above method may include steps other than those described above. For example, the above method may also include a step of machining (e.g., cutting, surface finishing, surface roughening, etc.) either the target or the backing plate. For example, the above method may further include a process of coating other components onto the surface of either the target or the backing plate. Alternatively, the above method may further include a process of forming a layer composed of other components on the surface of either the target or the backing plate.

[0079] 2-1. Target Manufacturing The steps of providing the target, insert, and backing plate may include manufacturing the target. The target can also be manufactured by melt casting. In this case, further processing such as rolling and cutting can be performed. Alternatively, the target can be manufactured by sintering powder. Preferably, the target is manufactured by powder sintering.

[0080] When a target is manufactured by powder sintering, there are no particular limitations on the manufacturing conditions, and manufacturing conditions known in the art can be used.

[0081] Preferably, the following procedures may include powder sintering.

[0082] • Implement HP (Hot Press) • Implement HIP or calendering treatment First, the HP step involves filling a mold with tungsten powder as raw material and applying a load to it for heat treatment. The tungsten powder used here is preferably tungsten powder with a particle size of 5 μm or less. In the HP step, the temperature is increased at an appropriate heating rate, and a load suitable for each temperature range is applied to raise the temperature to the HP temperature, which is then maintained at the HP temperature for a specified time. The heating rate is preferably about 2 to 10 °C / min. In this HP step, the load applied is preferably adjusted and varied appropriately in the temperature range of 600 to less than 1200 °C and in the temperature range above 1200 °C. Degassing occurs in the initial stage of heating in the HP step; therefore, if a high load is applied during this process, sintering will occur without sufficient degassing, resulting in a sintered body that is not dense and contains a large amount of residual gases such as oxygen. To address this, in the HP step, a lower load is applied in the low-temperature range, and a higher load is applied in the high-temperature range, thereby increasing the density of the sintered body and producing a sintered body with low residual oxygen content. Specifically, the preferred load-bearing pressure in the temperature range of 600 to below 1200°C is 80 to 150 kgf / cm². 2 The load-bearing pressure in the temperature range above 1200℃ is set at 200~350 kgf / cm². 2 The holding time is approximately 1600–1900 °C. Furthermore, in the heating step, repeatedly holding the temperature at a certain time for a specific duration is effective in obtaining a randomly oriented sintered body with high density. The preferred HP temperature is approximately 1600–1900 °C. If the HP temperature is too low, the density will not increase sufficiently; if it is too high, it will hinder the formation of a carbide layer on the tungsten surface, which is undesirable. If the heating rate is too fast, degassing in the HP step will not be sufficient, which is also undesirable. It is known that a slow heating rate will also lead to reduced productivity. The holding time in this step is approximately 30–480 minutes, which can be adjusted appropriately based on factors such as temperature. The holding time at the HP temperature can also be set and adjusted in the same way. A vacuum environment is preferred for the HP step.

[0083] Regarding the HP-treated molded body, in order to increase the average grain size of the tungsten crystals and achieve high density, it is effective to perform HIP treatment on the HP-treated molded body. In one embodiment, the HIP treatment temperature can be 1600°C or higher, and the treatment time can be 2 hours or higher. Preferably, the HIP treatment temperature can be 1800°C or higher, and the treatment time can be 5 hours or higher. By setting the HIP treatment conditions to the above-preferred conditions, a tungsten sputtering target with an average tungsten crystal grain size exceeding 100 μm can be obtained. The HIP treatment pressure can be 1600–1900 kgf / cm². 2 Adjustments are made for standardization. There is no particular upper limit to the temperature during HIP treatment, but for cost reasons, it is preferably below 2200°C. There is no particular upper limit to the time of HIP treatment, but for cost reasons, it is preferably below 8 hours. The environment for HIP treatment is preferably a non-reactive environment such as an argon atmosphere.

[0084] 2-2. Manufacturing of the sputtering target assembly After the target is manufactured, the target, insert, and backplate are assembled to create a sputtering target assembly. Specifically, the target, insert, and backplate are sequentially stacked from top to bottom and then subjected to HIP (High-Intensity Interconnect) treatment to bond them together.

[0085] Regarding the conditions for HIP treatment, the pressure during HIP treatment can range from 1000 to 2200 kgf / cm². 2 Adjusted to the standard, the preferred pressure for HIP treatment is 1700 kgf / cm². 2 The above. Furthermore, the temperature can be 400°C or higher, preferably 500°C or higher. There is no particular limitation on the upper limit, but it is preferably set to a temperature not exceeding the melting point of at least one of the insert and the backing plate, for example, 800°C or lower.

[0086] The duration can be 2 hours or more, preferably 4 hours or more. There is no specific upper limit; for example, it can be less than 10 hours.

[0087] 3. Application The above-described sputtering target assembly can be used for the purpose of forming thin films by sputtering. Therefore, in one embodiment, the present invention relates to tungsten films prepared using the above-described sputtering target assembly and methods for manufacturing the same. Preferably, in one embodiment, the present invention relates to semiconductors having tungsten films prepared using the above-described sputtering target assembly and methods for manufacturing the same.

[0088] For example, the manufacturing method may include steps such as arranging the substrate and sputtering target assembly in opposite directions within a chamber, introducing an inactive gas (e.g., Ar), and applying a voltage to form a thin film.

[0089] The sputtering target assembly in one embodiment of the present invention has high peel strength. Therefore, the sputtering target assembly in one embodiment of the present invention is advantageous in suppressing the generation of defects during sputtering.

[0090] [Example] Prepare various targets made of tungsten. Specifically, prepare multiple targets made of tungsten with various average particle sizes (for the method of measuring particle size, refer to "1-4. Particle Size of Targets"). Furthermore, in Examples 1, 3, and Comparative Examples 1, 2, the optical microscope was set to 200x magnification, and three straight lines of approximately 475 μm were drawn. The L / N ratio was calculated, and the average of each calculation result was taken as the average particle size, calculated in 5 μm increments (for example, 25 μm for particles larger than or equal to 22.5 μm but less than 27.5 μm, and 30 μm for particles larger than or equal to 27.5 μm but less than 32.5 μm). In Examples 2, 4, 5, and Comparative Example 3, the optical microscope was set to 50x magnification, and three straight lines of approximately 1900 μm were drawn. The L / N ratio was calculated, and the average of each calculation result was taken as the average particle size, calculated in 5 μm increments.

[0091] Regarding the inserts, inserts made of Al (Comparative Examples 1 and 2) and inserts made of Cu (Examples 1 to 5 and Comparative Example 3) were prepared. The inserts made of Cu were made of oxygen-free copper (JIS H 3100, C1020) and tough copper (JIS H3100, C1100).

[0092] Furthermore, in Comparative Example 1, in order to strengthen the bonding between the target and the backplate, the bonding surface on the target side was machined using the method described in WO 2016 / 017432.

[0093] Regarding the backplate, a backplate made of CuZn was prepared (Comparative Examples 1-3, Cu 63% by mass, Zn 37% by mass), a backplate made of Ti (Examples 1-4), and a backplate made of Ti alloy (specifically, Ti-6Al-4V) (Example 5).

[0094] Based on the conditions shown in Table 1, the target, insert, and backing plate are stacked sequentially from top to bottom. The stack is then subjected to HIP treatment. The HIP treatment pressure is set to 1800 kgf / mm². 2 The heating rate was set to 100–300 °C / h. The ambient atmosphere was set to argon. The temperature and time were set to the conditions shown in Table 1.

[0095] After bonding using HIP treatment, the self-sputtered target assembly, in Figure 5Sample pieces were cut from the indicated locations. Furthermore, for each sample piece, the peel strength was measured by stretching it at a speed of 0.5 mm / min along a direction perpendicular to the mating surface of the target, etc. The instrument used for this measurement was an Autograph AG-100kNX plus precision universal testing machine manufactured by Shimadzu Corporation.

[0096] Take the four points in the outer perimeter region (refer to) Figure 1 and Figure 2 The lowest peel strength at the time of measurement, and 10 points in all areas (refer to) Figure 5 and Figure 6 The average peel strength measured is shown in Table 1.

[0097] [Table 1] Compared to the comparative example where the insert is made of Al, sufficient strength is ensured in the peripheral region of the sputtering target assembly where the insert is made of Cu. Furthermore, in some embodiments, improved strength is also observed in the entire region. Additionally, unlike Comparative Example 1, no surface finishing was performed in Comparative Example 2. As a result, it was impossible to fabricate a sample in Comparative Example 2.

[0098] Furthermore, unlike Comparative Example 1, no embossing was performed in Example 1. Nevertheless, comparing the results of Comparative Example 1 and Example 1, Example 1 showed superior minimum peel strength at four points in the outer peripheral region compared to Comparative Example 1. Therefore, it is demonstrated that bond strengthening can be achieved based on the insert and backing plate used in the examples, as well as the HIP conditions for bonding. Furthermore, comparing the results of Example 4 and Comparative Example 3, it is demonstrated that the effect of preventing cracking can be improved through an appropriate combination of insert material and backing plate. Moreover, as shown in Example 5, it is demonstrated that the same effect is achieved even when the backing plate is a Ti alloy.

[0099] The specific embodiments of the invention have been described above. The above embodiments are merely specific examples, and the 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. Furthermore, unless otherwise specified, the order of some steps may be changed with other steps, or further steps may be added between specific two steps. The scope of the invention is defined by the scope of the claims.

Claims

1. A sputtering target assembly, comprising a target, a backing plate, and an insert. The target is composed of W. The backplate contains Ti or a Ti alloy. The insert contains Cu or a Cu alloy. The average particle size of the target is over 20 μm.

2. The sputtering target assembly as described in claim 1, wherein, The target is circular, and the lowest peel strength measured at four points on the outer periphery of the target and the backing plate was 6 kgf / mm². 2 above.

3. The sputtering target assembly as described in claim 2, wherein, The average peel strength measured at 10 points across the entire area of ​​the target and backplate was 6 kgf / mm². 2 above.

4. The sputtering target assembly as described in any one of claims 1 to 3, wherein, The mating surface of the target has no machining marks.

5. The sputtering target assembly as described in any one of claims 1 to 4, wherein, The insert consists of Cu and unavoidable impurities, with the Cu having a purity of 99.9% by mass or higher.

6. The sputtering target assembly as described in any one of claims 1 to 5, wherein, The insert consists of Cu and unavoidable impurities, with an oxygen content of less than 10 ppm by mass.

7. A film prepared using the sputtering target assembly according to any one of claims 1 to 6.

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