Tantalum target material and preparation method and application thereof

Abstract

The invention belongs to the field of target material preparation, and particularly discloses a tantalum target material and a preparation method and application thereof. According to the method, stress annealing, multiple groups of cold forging and pressing and heat treatment, two-stage rolling, intermediate heat treatment and recrystallization annealing are sequentially carried out on the tantalum ingot, all the steps are matched with one another, so that grain distribution of the tantalum target is more uniform, grains are finer, and on the basis that good uniformity and film quality of sputtering film forming of the tantalum target are kept, the yield of the tantalum target is improved. The ratio of the average area of crystal grains with the {100} face oriented in the normal direction to the average area of crystal grains with the {111} face oriented in the normal direction is increased, the deposition rate of sputter coating is increased, and the purpose of improving the production efficiency of film forming is achieved.

Description

Technical Field

[0001] The invention belongs to the field of target material preparation, and in particular relates to a tantalum target material and a preparation method and application thereof. Background Art

[0002] In the chip manufacturing process, the raw material for the sputtering coating of the core process is high-purity metal target material. In the 65nm, 45nm and the most advanced 7nm line width process, copper (Cu) interconnection technology gradually replaces aluminum (Al) interconnection technology. Ta film, as a diffusion barrier layer for Cu interconnection, can prevent copper atoms from diffusing into the Si matrix to reduce the current density and the performance of components. Tantalum target material, as the raw material for sputtering Ta film, has gradually become one of the key raw materials in the semiconductor industry.

[0003] Tantalum targets are used in the preparation of semiconductor devices through magnetron sputtering. The principle is to use physical vapor deposition technology (PVD) to bombard tantalum targets with high pressure accelerated gaseous Ar ions, so that tantalum atoms or ion clusters on the tantalum targets are sputtered out and deposited on silicon wafers in the form of thin films. Tantalum is a body-centered cubic (BCC) metal and a high-layer dislocation metal. The internal structure, grain size and crystal orientation of tantalum targets have a great influence on the preparation and performance of integrated circuit metal films. Therefore, the quality of tantalum targets directly affects the quality of thin films formed by magnetron sputtering, and is also a key factor in determining whether the final tantalum target assembly can meet the needs of semiconductor sputtering. In the process of magnetron sputtering using tantalum targets, the following phenomena generally occur: (1) From the influence of grain orientation on sputtering rate (S), S{110}>S{100}>S{111}; (2) As the grain size increases, the film deposition rate tends to decrease; (3) Within the appropriate grain size range, the plasma impedance when the target is used is low, the film deposition rate is high and the film thickness uniformity is good. It can be found that the size, orientation and consistency of the grains affect the film deposition rate and film thickness uniformity. In addition, if the proportion of {110} or {100} is increased and the proportion of {111} is reduced at the appropriate grain size, the sputtering rate can be increased, the film formation rate can be increased, and the production efficiency can be improved. However, the control technology of grains and crystal orientation has always been a key difficulty in the industry.

[0004] For example, in patent document US2015 / 0211107A1, the ingot is hot forged, and the surface is coated with glass powder to protect the ingot, so as to improve the uniformity of the internal structure. This method is relatively complicated, and the uniformity of the structure is difficult to control. When the tantalum material is deformed by hot forging, the ingot is severely oxidized, which is difficult to achieve in production. Even if surface protection is used, the contact friction between the ingot and the mold during the strong deformation process will make the protective layer ineffective, and thermal deformation will increase the difficulty of dislocation accumulation, causing grain growth or poor uniformity, resulting in a low sputtering rate when sputtering thin films. Summary of the invention

[0005] In view of the problem in the prior art that it is difficult to control the crystal orientation of grains when preparing tantalum targets, resulting in a low sputtering rate of the target materials, the present invention provides a tantalum target material and a preparation method and application thereof.

[0006] To achieve the above purpose, the following technical solutions are specifically included:

[0007] In one aspect, the present invention provides a method for preparing a tantalum target, comprising the following steps:

[0008] (1) annealing the tantalum ingot obtained by electron beam melting to obtain an annealed tantalum ingot;

[0009] (2) cold forging and heat treating the annealed tantalum ingot in sequence to obtain a forged tantalum ingot;

[0010] The number of times of sequentially performing the cold forging and heat treatment is ≥2; the cold forging includes sequentially performing upsetting and drawing;

[0011] (3) subjecting the forged tantalum ingot to first-stage cross rolling, heat treatment, and second-stage cross rolling in sequence to obtain a rolled tantalum ingot;

[0012] In the first stage cross rolling, more than 4 passes are rolled, and the rolling directions of two adjacent passes differ by 90°; in the second stage cross rolling, more than 4 passes are rolled, and the rolling direction of the first pass in the second stage cross rolling differs by 45° to 135° from the rolling direction in the first stage, and the rolling directions of two adjacent passes differ by 90°; the total deformation of the first stage cross rolling and the second stage cross rolling is 65%-90%;

[0013] (4) Annealing the rolled tantalum ingot under vacuum conditions to obtain a tantalum target; the annealing treatment adopts a step-by-step heating method.

[0014] The tantalum ingots obtained by electron beam melting are annealed to remove stress in the tantalum ingots and reduce the risk of subsequent forging cracking, providing a basis for grain refinement, reducing the {111} orientation and increasing the proportion of {100} oriented grains.

[0015] The tantalum ingot is cold forged, which includes upsetting and drawing. This method can break the coarse columnar crystals in the cast state of the tantalum ingot and refine the grains. The orientation distribution in the grains can be improved by controlling the two forging methods of upsetting and drawing and the deformation rate. Heat treatment is performed after cold forging, which controls the orientation distribution and proportion of {111}, {110}, and {100}, so as to intervene and optimize the crystal orientation control of subsequent rolling in advance. A combination of multiple cold forging and heat treatment is adopted, and the cold forging and heat treatment cooperate with each other to further refine the grains as a whole and increase their orientation degree.

[0016] Cross-rolling is performed in two stages and heat treatment is performed during the two-stage cross-rolling, and the rolling directions of the two stages are at a certain angle, which can further refine the grains, increase the area ratio of {100} and {111} orientations, and increase the sputtering rate.

[0017] The rolled tantalum target blank is annealed in a step-by-step heating manner to achieve recrystallization, further refine the grains, and increase the area ratio of the {100} and {111} orientations.

[0018] In the method of the present invention, the tantalum ingot is subjected to stress annealing, multiple groups of cold forging and heat treatment, two-stage rolling, intermediate heat treatment, and recrystallization annealing in sequence, and each step cooperates with each other to make the grain distribution of the tantalum target more uniform, the grains finer, and the proportion of {100} oriented grains can be increased, and the proportion of {111} oriented grains can be reduced. Therefore, the method of the present invention, when the tantalum target grain size is relatively suitable, by increasing the proportion of {100} oriented grains and reducing the proportion of {111} oriented grains, achieves the improvement of the deposition rate of the sputtering film of the tantalum target while maintaining the good uniformity and film quality of the sputtering film of the tantalum target, and improves the film production efficiency.

[0019] Preferably, the purity of the tantalum ingot obtained by electron beam melting is ≥99.99wt%, more preferably 99.99wt%-999.995wt%.

[0020] Preferably, in step (1), the temperature of the annealing treatment is 1000-1400° C., and the time of the annealing treatment is 1-3 hours.

[0021] The tantalum ingots obtained by electron beam melting are annealed to remove stress in the tantalum ingots, reduce the risk of subsequent forging cracking, and provide a basis for grain refinement, reducing the {111} orientation and increasing the proportion of {100} oriented grains. At the above-mentioned annealing temperature and time, the stress removal effect is better, the grain size is smaller, and the ratio of the grain area of ​​{100} orientation and {111} orientation is higher.

[0022] Preferably, in step (2), the cold forging and heat treatment are performed sequentially 2-4 times.

[0023] Preferably, in step (2), in the cold forging, the number of upsetting and drawing is 1-4 times in sequence, the deformation rate of each upsetting is 20%-50%, and the deformation rate of each drawing is 30%-70%; the temperature of the heat treatment is 1000-1300°C, and the time of the heat treatment is 1-4h.

[0024] Cold forging includes 1-4 times of upsetting and drawing, while controlling the deformation amount, which can further break up the coarse grains in all directions and achieve the purpose of grain refinement.

[0025] Preferably, in step (3), in the first stage cross-rolling, 6 to 20 passes are performed; in the second stage cross-rolling, 6 to 20 passes are performed.

[0026] In each stage, increasing the number of rolling passes can further refine the grains to a certain extent, but the process cycle is increased. Within the above range of passes, both the grain refinement effect and the benefit can be taken into account.

[0027] Preferably, in step (3), the temperature of the heat treatment is 900-1200° C., and the time of the heat treatment is 1-3 h.

[0028] Preferably, in step (3), in the first-stage cross-rolling and the second-stage cross-rolling, the rolling rates are each selected from 10-50 m / min, and the rolling mill diameters are each selected from above 500 mm.

[0029] Preferably, in step (4), the annealing temperature is 900-1200°C, the annealing time is 2-4h, and the step heating method specifically includes the following steps: heating from room temperature to 300-500°C within 1-3h, and keeping warm for 1-2h; then continuing to heat to 900-1200°C within 2-4h, and keeping warm for 2-4h.

[0030] The step-by-step heating method under the above conditions is better in terms of grain refinement.

[0031] Preferably, in step (4), the vacuum degree of the vacuum condition is less than or equal to 5×e -3 Pa.

[0032] On the other hand, the present invention provides a tantalum target material obtained by the preparation method of the tantalum target material.

[0033] Preferably, the average particle size of the tantalum target grains is 60-100 μm, and the structure of the tantalum target on a cross section perpendicular to the sputtering surface is observed using electron backscatter diffraction. The average area of ​​the grains oriented along the normal direction of the {111} plane is 10%-26.5%, and the average area of ​​the grains oriented along the normal direction of the {100} plane is 25%-55%.

[0034] Preferably, in the tantalum target material, the ratio of the average area of ​​the grains oriented along the normal direction of the {100} plane to the average area of ​​the grains oriented along the normal direction of the {111} plane is 1.5-1.9.

[0035] In addition, the present invention also provides an application of the tantalum target material in the preparation of integrated circuits.

[0036] The tantalum target material of the present invention has uniformly distributed grains, a suitable average grain size, a high proportion of {100} grain orientation, a low proportion of {111} grain orientation, a high deposition rate and uniformity of sputtering coating, and a high film production efficiency. The film forming speed can be appropriately increased under high-power sputtering conditions, which meets the requirements of semiconductor sputtering and can further improve the client's use effect and the competitiveness of integrated circuit processing companies.

[0037] Compared with the prior art, the present invention has the following beneficial effects: in the method of the present invention, the tantalum ingot is subjected to stress annealing, multiple groups of cold forging and heat treatment, two-stage rolling and intermediate heat treatment, and recrystallization annealing in sequence, and each step cooperates with each other, so that the grain distribution of the tantalum target is more uniform and the grains are finer. On the basis of maintaining good uniformity and film quality of the sputtering film of the tantalum target, the ratio of the average area of ​​the grains oriented along the normal direction of the {100} plane to the average area of ​​the grains oriented along the normal direction of the {111} plane is increased, the deposition rate of the sputtering coating is increased, and the purpose of improving the production efficiency of the film is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the phase structure diagram of the tantalum target material in Example 1.

[0039] Figure 2 This is the phase structure diagram of the tantalum target of Example 1 analyzed by the EBSD method. DETAILED DESCRIPTION

[0040] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below through specific examples. The test methods used in the examples and / or comparative examples are conventional methods unless otherwise specified; the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0041] The tantalum ingot obtained by electron beam melting used below has a purity of 99.995wt%, and the contents of W, Mo, and Nb are less than 10ppm. In the electron beam melting preparation process, the electron beam melting main high voltage is 35-50KV, the secondary high voltage is 1-3KV, the emission current is 2-5A, the temperature is 2800-3200℃, and the time is 3-6h. The same tantalum ingot is used in each embodiment and comparative example.

[0042] Example 1

[0043] A method for preparing a tantalum target comprises the following steps:

[0044] (1) annealing the tantalum ingot obtained by electron beam melting at 1300° C. and keeping the temperature for 2 hours to obtain an annealed tantalum ingot;

[0045] (2) The annealed tantalum ingot is subjected to a combination of cold forging and heat treatment twice in sequence to obtain a forged tantalum ingot; the forging environment temperature is maintained at 0-30° C., which belongs to cold forging and includes the following specific steps:

[0046] (2-1) The annealed tantalum ingot is subjected to the first upsetting, and the upsetting deformation rate is 50%; the first drawing, and the drawing deformation rate is 70%; the second upsetting, and the upsetting deformation rate is 50%; the second drawing, and the drawing deformation rate is 70%; the third upsetting, and the upsetting deformation rate is 50%; the third drawing, and the drawing deformation rate is 70%;

[0047] (2-2) heat treatment at 1150°C for 2h;

[0048] (2-3) The annealed tantalum ingot is subjected to the first upsetting, with an upsetting deformation rate of 50%; the first drawing, with a drawing deformation rate of 70%; the second upsetting, with an upsetting deformation rate of 50%; the second drawing, with a drawing deformation rate of 70%; the third upsetting, with an upsetting deformation rate of 50%; the third drawing, with a drawing deformation rate of 70%;

[0049] (2-4) heat treatment at 1150°C for 2 h;

[0050] (3) subjecting the forged tantalum ingot to first-stage cross rolling, heat treatment, and second-stage cross rolling in sequence to obtain a rolled tantalum ingot;

[0051] Among them, the rolling mill selects rollers with a diameter of more than 500mm, the rolling speed is 25m / min, and the rolling environment temperature is maintained at 0-30℃, which belongs to cold rolling; the specific process is as follows:

[0052] (3-1) In the first stage of cross rolling, the first pass is rolled in the 0° direction (the pressing amount each time is 1-10 mm, the same below), the second pass is rolled in the 90° direction, the third pass is rolled in the 0° direction, the fourth pass is rolled in the 90° direction, and so on. The rolling directions of the two adjacent passes differ by 90°, and a total of 8 passes are rolled;

[0053] (3-2) performing heat treatment at a temperature of 1000° C. for 2 h;

[0054] (3-3) In the second stage of cross rolling, the first pass is rolled in the direction of 135° (or in the direction forming an angle of 135° with the direction of 90°), the second pass is rolled in the direction of 225° (forming an angle of 90° with the previous pass), the third pass is rolled in the direction of 135°, the fourth pass is rolled in the direction of 225°, and so on. The rolling directions of two adjacent passes differ by 90°, and a total of 8 passes are rolled. The total deformation in the first stage of cross rolling and the second stage of cross rolling is 75%;

[0055] (4) The rolled tantalum ingot is placed under vacuum conditions (vacuum degree ≤ 5*E -3 Pa), annealing at 1100° C. to obtain a tantalum target;

[0056] The annealing treatment adopts a step-by-step heating method, which specifically includes the following steps:

[0057] The temperature was raised from room temperature (20°C) to 350°C within 2 hours and kept at this temperature for 1 hour; the temperature was further raised to 1100°C within 3 hours and kept at this temperature for 3 hours.

[0058] Example 2

[0059] The difference between this embodiment and embodiment 1 is that the annealing temperature in step (1) of this embodiment is 1000° C., and the rest of the process is the same.

[0060] Example 3

[0061] The difference between this embodiment and embodiment 1 is that the annealing temperature in step (1) of this embodiment is 1400° C., and the rest of the process is the same.

[0062] Example 4

[0063] The difference between this embodiment and embodiment 1 is that in step (2) of this embodiment, a combination of cold forging and heat treatment is performed three times in sequence, and the rest of the process is the same.

[0064] Example 5

[0065] The difference between this embodiment and embodiment 1 is that in step (2) of this embodiment, a combination of cold forging and heat treatment is performed four times in sequence, and the rest of the process is the same.

[0066] Example 6

[0067] The difference between this embodiment and embodiment 1 is that in this embodiment, in the combined treatment of cold forging and heat treatment in step (2), the heat treatment temperature is 1000° C., and the rest of the process is the same.

[0068] Example 7

[0069] The difference between this embodiment and embodiment 1 is that in this embodiment, in the combined treatment of cold forging and heat treatment in step (2), the heat treatment temperature is 1300° C., and the rest of the process is the same.

[0070] Example 8

[0071] The difference between this embodiment and embodiment 1 is that the heat treatment temperature in step (3-2) of this embodiment is 900°C.

[0072] Example 9

[0073] The difference between this embodiment and embodiment 1 is that the heat treatment temperature in step (3-2) of this embodiment is 1200° C., and the rest of the process is the same.

[0074] Comparative Example 1

[0075] The difference between this comparative example and Example 1 is that this comparative example lacks step (1) annealing treatment, and the rest of the processes are the same.

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 1 is that in step (2) of this comparative example, only one combined treatment of cold forging and heat treatment is performed, and the rest of the processes are the same.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 1 is that in step (2) of this comparative example, a combined treatment method of cold forging and heat treatment is not adopted, only cold forging is performed without heat treatment, and the rest of the process is the same.

[0080] Comparative Example 4

[0081] The difference between this comparative example and Example 1 is that in step (3) of this comparative example, the direction of the cross-rolling in the second stage is the same as that in the first stage, which are combinations of 0° and 90° directions in sequence, and the rest of the process is the same.

[0082] Comparative Example 5

[0083] The difference between this comparative example and Example 1 is that in step (3) of this comparative example, no heat treatment is performed, and the rest of the process is the same.

[0084] Comparative Example 6

[0085] The difference between this comparative example and Example 1 is that in step (4) of this comparative example, a step-by-step heating method is not used, but the temperature is directly raised from room temperature to 1100° C. within 5 hours and kept at this temperature for 3 hours.

[0086] Tantalum target testing:

[0087] (1) Grain size: Use a metallographic microscope and analysis software to measure the average grain size;

[0088] (2) {100} and {111} orientation ratio: The test was conducted using SEM and EBSD (electron backscatter diffraction) devices to obtain the organizational data diagram of the rolling surface normal (ND) direction of the cross section perpendicular to the target sputtering surface, and the analysis software was used to analyze the {100} and {111} orientations and issue a report, and the average area ratio of the grains of the two orientations was calculated; wherein, the grains with the {111} plane oriented along the ND include the grains with an orientation deviation of the {111} plane within 15° relative to the rolling surface normal (ND), and the grains with the {100} plane oriented along the ND include the grains with an orientation deviation of the {100} plane within 15° relative to the rolling surface normal (ND).

[0089] Table 1

[0090]

[0091] It can be seen from the above embodiments that the average grain size of the tantalum target material prepared by the present invention is 60-100 μm, and the structure of the tantalum target material on a cross section perpendicular to the sputtering surface is observed by electron backscatter diffraction. The average area of ​​the grains oriented along the normal direction of the {111} plane is 10%-26.5%, and the ratio of the average area of ​​the grains oriented along the normal direction of the {100} plane to the average area of ​​the grains oriented along the normal direction of the {111} plane is 1.5-1.9.

[0092] It can be seen from Example 1 and Comparative Example 1 that the tantalum ingot obtained by electron beam melting is annealed to remove stress in the tantalum ingot, reduce the risk of subsequent forging cracking, refine the grains, and significantly increase the ratio of the grain area of ​​{100} orientation to {111} orientation. And it can be seen from Examples 1-3 that the annealing temperature has a certain influence on the grain size of the tantalum target and the ratio of the grain area of ​​{100} orientation to {111} orientation. When the annealing temperature is 1000-1400°C, the grain size of the tantalum target is smaller and the ratio of the grain area of ​​{100} orientation to {111} orientation is higher.

[0093] It can be seen from the comparison between Example 1 and Comparative Example 2 that the number of cold forging and heat treatment needs to reach ≥2 times, so as to effectively refine the grains and increase the ratio of the grain area of ​​{100} orientation and {111} orientation. And it can be seen from Examples 1 and 4-5 that continuing to increase the number of cold forging and heat treatment to 4 times can still maintain a smaller grain size and a higher ratio of the grain area of ​​{100} orientation and {111} orientation. Continuing to increase the number will significantly increase the working hours and the efficiency is not high. And it can be seen from Examples 1 and 6-7 that the temperature of the heat treatment after cold forging has a certain effect on the grain size of the tantalum target and the ratio of the grain area of ​​{100} orientation and {111} orientation. At the intermediate heat treatment temperature of 1000-1300°C, the grain size of the tantalum target is smaller and the ratio of the grain area of ​​{100} orientation and {111} orientation is higher.

[0094] It can be seen from the comparison between Example 1 and Comparative Examples 4-5 that in step (3), the two stages of cross rolling must adopt different directions, and heat treatment must be added between the two stages of cross rolling, otherwise it is impossible to effectively refine the grains and increase the ratio of the grain areas of the {100} orientation and the {111} orientation. And it can be seen from Examples 1 and 8-9 that the temperature of the intermediate heat treatment in this stage has a certain influence on the grain size of the tantalum target and the ratio of the grain areas of the {100} orientation and the {111} orientation. When the intermediate heat treatment temperature is 900-1200°C, the grain size of the tantalum target is smaller and the ratio of the grain areas of the {100} orientation and the {111} orientation is higher.

[0095] It can be seen from the comparison between Example 1 and Comparative Example 6 that the step-by-step heating method can achieve recrystallization and further refine the grains.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a tantalum target, characterized in that: The steps include: (1) annealing the tantalum ingot obtained by electron beam melting to obtain an annealed tantalum ingot; (2) cold forging and heat treating the annealed tantalum ingot in sequence to obtain a forged tantalum ingot; The number of times of sequentially performing the cold forging and heat treatment is ≥2; the cold forging includes sequentially performing upsetting and drawing; (3) subjecting the forged tantalum ingot to first-stage cross rolling, heat treatment, and second-stage cross rolling in sequence to obtain a rolled tantalum ingot; In the first stage cross rolling, more than 4 passes are rolled, and the rolling directions of two adjacent passes differ by 90°; in the second stage cross rolling, more than 4 passes are rolled, and the rolling direction of the first pass in the second stage cross rolling differs by 45° to 135° from the rolling direction in the first stage, and the rolling directions of two adjacent passes differ by 90°; the total deformation of the first stage cross rolling and the second stage cross rolling is 65%-90%; (4) Annealing the rolled tantalum ingot under vacuum conditions to obtain a tantalum target; the annealing treatment adopts a step-by-step heating method.

2. The method for preparing a tantalum target according to claim 1, characterized in that: In step (1), the temperature of the annealing treatment is 1000-1400° C., and the time of the annealing treatment is 1-3 hours.

3. The method for preparing a tantalum target material according to claim 1, characterized in that: In step (2), the cold forging and heat treatment are performed sequentially 2-4 times.

4. The method for preparing a tantalum target material according to claim 1, wherein: In step (2), during the cold forging, upsetting and drawing are performed 1-4 times in sequence, the deformation rate of each upsetting is 20%-50%, and the deformation rate of each drawing is 30%-70%; the temperature of the heat treatment is 1000-1300°C, and the time of the heat treatment is 1-4h.

5. The method for preparing a tantalum target according to claim 1, wherein: In step (3), in the first stage cross rolling, 6 to 20 passes are performed; in the second stage cross rolling, 6 to 20 passes are performed.

6. The method for preparing a tantalum target material according to claim 1, characterized in that: In step (3), the temperature of the heat treatment is 900-1200° C., and the time of the heat treatment is 1-3 hours.

7. The method for preparing a tantalum target according to claim 1, characterized in that: In step (4), the annealing temperature is 900-1200°C, the annealing time is 2-4h, and the step heating method specifically includes the following steps: heating from room temperature to 300-500°C within 1-3h, and keeping warm for 1-2h; then continuing to heat to 900-1200°C within 2-4h, and keeping warm for 2-4h.

8. A tantalum target material obtained by the method for preparing a tantalum target material according to any one of claims 1 to 7.

9. The tantalum target material according to claim 8, characterized in that The average particle size of the tantalum target grains is 60-100 μm. The structure of the tantalum target on a cross section perpendicular to the sputtering surface is observed using electron backscatter diffraction. The average area of ​​the grains oriented along the normal direction of the {111} plane is 10%-26.5%, and the average area of ​​the grains oriented along the normal direction of the {100} plane is 25%-55%.

10. Use of the tantalum target material according to claim 8 or 9 in the preparation of integrated circuits.

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