Preparation method of tantalum target blank with high uniformity of tissue texture

Abstract

The invention discloses a preparation method of a tantalum target blank with a highly-uniform structure, which comprises the following steps: sequentially carrying out primary forging, secondary forging and tertiary forging on high-purity tantalum subjected to electron beam melting, and then carrying out primary cross rolling on the high-purity tantalum subjected to tertiary forging to obtain an intermediate target blank; and finally, the middle target blank is averagely segmented in the thickness direction and then subjected to secondary cross rolling, and the tantalum target blank is obtained. The tantalum target blank prepared through the method is fine in microstructure and uniform in orientation distribution, the average grain size is smaller than or equal to 60 micrometers in the thickness direction of the tantalum target blank, the {100} texture proportion is larger than or equal to 35%, the {111} texture proportion is smaller than or equal to 30%, the diameter of the prepared tantalum target blank is larger than or equal to 500 mm, the thickness of the prepared tantalum target blank is larger than or equal to 10 mm, and the sputtering coating requirement of 12-inch wafers can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of sputtering target blank preparation, and in particular relates to a method for preparing a tantalum target blank with highly uniform organizational texture. Background Art

[0002] The semiconductor industry is a strategic, basic and leading industry for the national economic and social development. In recent years, driven by the market, policy support and external pressure, my country's semiconductor industry has developed rapidly and its overall strength has been significantly improved. Tantalum targets are widely used in the large-scale semiconductor industry as sputtering thin film materials for diffusion barrier layers in silicon chips and copper interconnection processes. Tantalum targets for semiconductors have high technical requirements and are difficult to prepare. Three key technologies need to be overcome during the preparation process: (1) purity ≥ 99.995% (4N5); (2) average grain size ≤ 80μm; (3) uniform distribution of the three textures {100}, {111} and {110}, without obvious texture bands. However, during the rolling process, tantalum targets are prone to form a texture gradient in which the surface layer is dominated by {100} texture and the core is dominated by {111} texture in the thickness direction. The sputtering rate of {111} texture is the slowest, which affects the production efficiency and the uniformity of film thickness, and thus affects the performance of semiconductor devices.

[0003] CN117144308A discloses a method for preparing tantalum target blanks by DS continuous rolling, wherein the tantalum target blanks are continuously rolled by multiple working rollers with different diameters, thereby simplifying the process, reducing the proportion of {111} texture, and achieving uniform distribution of {100} and {111} textures. However, the method has too high requirements on the equipment, requiring multiple high-precision rolling mills to run simultaneously, and the thickness of the tantalum target blanks prepared by the method is relatively small, which makes it difficult to meet the industrial production requirements of the tantalum target blanks. CN115029668B discloses a method for preparing high-performance tantalum sputtering targets by stacking, wherein the method fixes two intermediate tantalum target blanks by electron beam welding for cumulative cross-stacking. Although a tantalum target with uniform texture distribution is obtained, the flatness requirements of the intermediate tantalum target blanks are relatively high, and the welding parts are prone to cracking during the rolling process, which has an adverse effect on the stability of industrial production. It is urgent to propose a method for preparing tantalum target blanks with highly uniform organizational texture to meet industrial production requirements. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a tantalum target blank with highly uniform texture in view of the above-mentioned deficiencies of the prior art. The method controls the deformation amount during forging and rolling and adopts step-wise annealing and other means to make the prepared tantalum target blank have a small average grain size and uniform texture distribution, a high proportion of {100} texture and a low proportion of {111} texture, thereby meeting the process requirements of 12-inch wafer sputtering coating.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a tantalum target blank with high uniformity of structure and texture, characterized in that it comprises the following steps:

[0006] Step 1: One-time forging: The high-purity tantalum after electron beam melting is forged on a hydraulic press, and then subjected to high-temperature annealing treatment;

[0007] Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and then subjected to medium temperature annealing;

[0008] Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and then subjected to low-temperature annealing treatment;

[0009] Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross rolled on a rolling mill, and then subjected to medium temperature short time annealing to obtain an intermediate target blank;

[0010] Step 5, cutting the intermediate target blank: perform wire cutting along 1 / 2 of the thickness of the intermediate target blank in step 4, and divide the intermediate target blank into two groups evenly;

[0011] Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and then subjected to low temperature and long time annealing treatment to obtain a tantalum target blank.

[0012] The above-mentioned method for preparing a tantalum target blank with highly uniform organizational texture is characterized in that the purity of the high-purity tantalum in step one is 5N, and the tonnage of the hydraulic press is 2000T.

[0013] The above-mentioned method for preparing a tantalum target blank with highly uniform organizational texture is characterized in that the specific process of the one forging in step one includes: performing multiple upsetting passes on the high-purity tantalum along the axial direction to 1 / 2 of the original height, and then performing multiple drawing passes to the original height, each of the upsetting and drawing passes is a large deformation, and the deformation amount of each pass is 18% to 20%; the temperature of the high-temperature annealing treatment in step one is 1220°C to 1280°C, and the insulation time is 1h.

[0014] The above-mentioned method for preparing a tantalum target blank with highly uniform organizational texture is characterized in that the specific process of the secondary forging in step 2 includes: performing multiple upsetting passes on the high-purity tantalum along the axial direction to 1 / 2 of the original height, and then performing multiple drawing passes to the original height, each of the upsetting and drawing passes is a medium deformation, and the deformation amount of each pass is 12% to 13%; the temperature of the medium-temperature annealing treatment in step 2 is 1120°C to 1180°C, and the insulation time is 1h.

[0015] The above-mentioned method for preparing a tantalum target blank with highly uniform tissue texture is characterized in that the specific process of the three forgings in step three includes: multiple upsetting of the high-purity tantalum along the axial direction to 1 / 2 of the original height, and then multiple drawing to the original height, each of the upsetting and drawing is a small deformation, and the deformation amount of each pass is 8% to 10%; the temperature of the low-temperature annealing treatment in step three is 1020°C to 1080°C, and the insulation time is 1h.

[0016] The above-mentioned method for preparing a tantalum target blank with highly uniform organizational texture is characterized in that the roller diameter of the rolling mill in step 4 is 400 mm to 600 mm.

[0017] The above-mentioned method for preparing a tantalum target blank with highly uniform organizational texture is characterized in that the specific process of the cross-rolling described in step four includes: after each rolling pass is completed, the high-purity tantalum is rotated 90° clockwise along the normal for the next rolling pass, each pass is a larger deformation, the deformation amount is 14% to 16%, and the total deformation amount of one cross-rolling is 45% to 50%; the temperature of the medium-temperature short-time annealing treatment described in step four is 1120°C to 1180°C, and the insulation time is 20min to 40min.

[0018] The above-mentioned method for preparing a tantalum target blank with highly uniform tissue texture is characterized in that during the wire cutting process in step five, the cutting surface should be smooth and free of burrs.

[0019] The above-mentioned method for preparing a tantalum target blank with highly uniform tissue texture is characterized in that the specific process of the secondary cross rolling described in step six includes: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal for the next rolling pass, each pass is a small deformation, the deformation amount is 8% to 10%, and the total deformation amount of the secondary cross rolling is 50% to 60%; the temperature of the low-temperature long-time annealing treatment described in step six is ​​1020°C to 1080°C, and the insulation time is 1.5h to 2.5h.

[0020] The above-mentioned method for preparing a tantalum target blank with highly uniform tissue texture is characterized in that the tissue texture of the tantalum target blank in step six is ​​evenly distributed, the average grain size is ≤60μm, the {100} texture accounts for ≥35%, and the {111} texture accounts for ≤30%; the diameter of the tantalum target blank is ≥500mm and the thickness is ≥10mm.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The core structure of high-purity tantalum after electron beam melting is coarse, and it needs to go through multiple forging processes to break the core grains. During the drawing process of high-purity tantalum, the edges are subjected to large deformation and have good fluidity; the core is subjected to small deformation and has poor fluidity, so it is easy to have "shrinkage" defects during forging. The present invention adopts a step-by-step forging and annealing process. The use of large deformation in each pass of the first forging is beneficial to the stress on the core, and the deformation is transferred to the core, so that the large grains in the core are broken, thereby reducing the occurrence of macro defects such as "shrinkage". High-temperature annealing after the first forging can completely eliminate the deformed grains and allow the deformed grains to fully complete recrystallization. The use of small and medium deformation in each pass of the second and third forging can reduce the occurrence of macro crack defects caused by stress concentration during the forging process. Medium and low temperature annealing after the second and third forging is beneficial to slow down the transitional growth of grains and refine the grain size.

[0023] 2. Conventional rolling methods easily cause serious {111} texture in the core of high-purity tantalum. The present invention adopts cross-rolling, which can weaken the {111} texture in the core to a certain extent. The use of a larger deformation amount in each pass of a cross-rolling is conducive to the rolling force penetrating into the core, and the subsequent short-term annealing at a medium temperature prevents grain growth. The intermediate target blank cutting method is adopted to perform an average cut along 1 / 2 of the thickness of the intermediate target blank, so that the core position of the intermediate target blank becomes the edge position after the cutting is completed, which is conducive to the uniformity of the edge structure and the core structure after the second cross-rolling is completed. After the second cross-rolling, a low-temperature long-term annealing is used to allow the rolled deformed grains to recrystallize in the form of subcrystal nucleation, thereby suppressing the formation of {111} recrystallization texture and retaining more {100} recrystallization texture.

[0024] 3. The present invention controls key parameters such as deformation amount and annealing temperature during the processing and adopts an intermediate target blank cutting method to prepare a tantalum target blank with fine microstructure and uniform texture distribution. The {100} texture of the tantalum target blank accounts for ≥35%, the {111} texture accounts for ≤30%, and the average grain size along the thickness direction of the tantalum target blank is ≤60μm. The prepared tantalum target blank has a diameter of ≥500mm and a thickness of ≥10mm, which can meet the sputtering coating requirements of 12-inch wafers.

[0025] 4. The method of the present invention is not limited by equipment and has high production efficiency. It can be used for mass production of tantalum target blanks. The prepared tantalum target blanks have few macroscopic defects and processing waste, and the defect and waste ratio is less than 5%. The yield is high and the production cost can be greatly reduced.

[0026] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the preparation process of the tantalum target blank of the present invention.

[0028] Figure 2 This is a statistical chart of the average grain size of the tantalum target blanks prepared in Examples 1 to 6 of the present invention.

[0029] Figure 3 This is the orientation distribution diagram of the edge of the tantalum target blank along the thickness direction prepared in Example 1 of the present invention.

[0030] Figure 4 This is the orientation distribution diagram of the center of the tantalum target blank along the thickness direction prepared in Example 1 of the present invention.

[0031] Figure 5 This is the orientation distribution diagram of the edge along the thickness direction of the tantalum target blank prepared in Example 2 of the present invention.

[0032] Figure 6 This is the orientation distribution diagram of the center of the tantalum target blank along the thickness direction prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0033] The schematic diagram of the process for preparing a tantalum target blank with a highly uniform texture is as follows: Figure 1 As shown, it includes: performing primary forging, secondary forging and tertiary forging on the high-purity tantalum melted by electron beam in sequence, and then performing cross-rolling on the high-purity tantalum after tertiary forging to obtain an intermediate target blank; finally, the intermediate target blank is evenly cut in the thickness direction and cross-rolled twice to obtain a tantalum target blank.

[0034] Example 1

[0035] This embodiment provides a method for preparing a tantalum target blank with a highly uniform texture, comprising the following steps:

[0036] Step 1, one-time forging: the high-purity tantalum after electron beam melting is forged once on a hydraulic press, and the high-purity tantalum is subjected to high-temperature annealing after the one-time forging; the purity of the high-purity tantalum is 5N; the tonnage of the hydraulic press is 2000T; the specific process of the one-time forging is: the high-purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is a large deformation, and the deformation amount of each pass is 18%; the temperature of the high-temperature annealing treatment is 1220°C, and the holding time is 1h;

[0037] Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and after the secondary forging is completed, the high purity tantalum is subjected to medium temperature annealing; the specific process of the secondary forging is: the high purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is medium deformation, and the deformation amount of each pass is 12%; the temperature of the medium temperature annealing treatment is 1120°C, and the holding time is 1h;

[0038] Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and the high-purity tantalum is subjected to low-temperature annealing treatment after the three-time forging is completed; the specific process of the three-time forging is: the high-purity tantalum is upset for multiple times along the axial direction to 1 / 2 of the original height, and then drawn for multiple times to the original height, each of the upsetting and drawing passes is a small deformation, and the deformation amount of each pass is 8%; the temperature of the low-temperature annealing treatment is 1020°C, and the holding time is 1h;

[0039] Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross-rolled on the rolling mill, and after the one cross rolling is completed, the high purity tantalum is subjected to medium temperature short time annealing to obtain an intermediate target blank; the roller diameter of the rolling mill is 400mm; the specific process of the one cross rolling is as follows: after each rolling pass is completed, the high purity tantalum is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a larger deformation, the deformation amount of the pass is 14%, and the total deformation amount of the one cross rolling is 45%; the temperature of the medium temperature short time annealing treatment is 1120°C, and the holding time is 20min;

[0040] Step 5, cutting the intermediate target blank: perform wire cutting along 1 / 2 of the thickness of the intermediate target blank in step 4, and divide the intermediate target blank into two groups evenly; during the wire cutting process, the cutting surface should be smooth and free of burrs;

[0041] Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and after the secondary cross rolling is completed, the intermediate target blank is subjected to low-temperature long-time annealing treatment to obtain a tantalum target blank; the specific process of the secondary cross rolling is as follows: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal for the next rolling pass, each pass is a small deformation, the deformation amount of the pass is 8%, and the total deformation amount of the secondary cross rolling is 50%; the temperature of the low-temperature long-time annealing treatment is 1020°C, and the insulation time is 1.5h; the diameter of the tantalum target blank is ≥500mm, the thickness is ≥10mm, and the proportion of defects and waste is <5%.

[0042] The proportions of {100} texture and {111} texture of the tantalum target blank prepared in Example 1 are shown in Table 1. It can be seen that the proportion of {100} texture is 40% and the proportion of {111} texture is 21%. The average grain size statistics of the tantalum target blank are shown in Figure 2 , it can be seen that the average grain size is 55.2μm. Figure 3 and Figure 4 These are the orientation distribution diagrams of the edge and core of the tantalum target blank in Example 1 along the thickness direction. It can be seen that the {100} orientation and {111} orientation of the edge and core along the thickness direction are evenly distributed, and no texture band is generated. The prepared tantalum target blank can meet the sputtering coating requirements of 12-inch wafers.

[0043] Example 2

[0044] This embodiment provides a method for preparing a tantalum target blank with a highly uniform texture, comprising the following steps:

[0045] Step 1, one-time forging: the high-purity tantalum after electron beam melting is forged once on a hydraulic press, and the high-purity tantalum is subjected to high-temperature annealing after the one-time forging; the purity of the high-purity tantalum is 5N; the tonnage of the hydraulic press is 2000T; the specific process of the one-time forging is: the high-purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is a large deformation, and the deformation amount of each pass is 18%; the temperature of the high-temperature annealing treatment is 1250°C, and the holding time is 1h;

[0046] Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and after the secondary forging is completed, the high purity tantalum is subjected to medium temperature annealing; the specific process of the secondary forging is: the high purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is medium deformation, and the deformation amount of each pass is 12%; the temperature of the medium temperature annealing treatment is 1140°C, and the holding time is 1h;

[0047] Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and the high-purity tantalum is subjected to low-temperature annealing treatment after the three-time forging is completed; the specific process of the three-time forging is: the high-purity tantalum is upset multiple times along the axial direction to 1 / 2 of the original height, and then drawn multiple times to the original height, each of the upsetting and drawing passes is a small deformation, and the deformation amount of each pass is 8%; the temperature of the low-temperature annealing treatment is 1060°C, and the holding time is 1h;

[0048] Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross-rolled on the rolling mill, and after the one cross rolling is completed, the high purity tantalum is subjected to medium temperature short time annealing to obtain an intermediate target blank; the roller diameter of the rolling mill is 400mm; the specific process of the one cross rolling is as follows: after each rolling pass is completed, the high purity tantalum is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a larger deformation, the deformation amount of the pass is 14%, and the total deformation amount of the one cross rolling is 48%; the temperature of the medium temperature short time annealing treatment is 1140°C, and the holding time is 30min;

[0049] Step 5, cutting the intermediate target blank: perform wire cutting on the intermediate target blank described in step 4 along 1 / 2 of the thickness, and divide the intermediate target blank into two groups evenly; during the wire cutting process, the cutting surface should be smooth and free of burrs.

[0050] Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and after the secondary cross rolling is completed, the intermediate target blank is subjected to low-temperature long-time annealing treatment to obtain a tantalum target blank; the specific process of the secondary cross rolling is as follows: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal for the next rolling pass, each pass is a small deformation, the deformation amount of the pass is 9%, and the total deformation amount of the secondary cross rolling is 53%; the temperature of the low-temperature long-time annealing treatment is 1060°C, and the insulation time is 1.5h; the diameter of the tantalum target blank is ≥500mm, the thickness is ≥10mm, and the proportion of defects and waste is <5%.

[0051] The proportions of {100} texture and {111} texture of the tantalum target blank prepared in Example 2 are shown in Table 1. It can be seen that the proportion of {100} texture is 44% and the proportion of {111} texture is 26%. The average grain size statistics of the tantalum target blank are shown in Figure 2 , it can be seen that the average grain size is 41.3μm. Figure 5 and Figure 6 These are the orientation distribution diagrams of the edge and core of the tantalum target blank in Example 2 along the thickness direction. It can be seen that the {100} orientation and {111} orientation of the edge and core along the thickness direction are evenly distributed, and no texture band is generated. The prepared tantalum target blank can meet the sputtering coating requirements of 12-inch wafers.

[0052] Example 3

[0053] This embodiment provides a method for preparing a tantalum target blank with a highly uniform texture, comprising the following steps:

[0054] Step 1, one-time forging: the high-purity tantalum after electron beam melting is forged once on a hydraulic press, and the high-purity tantalum is subjected to high-temperature annealing after the one-time forging; the purity of the high-purity tantalum is 5N; the tonnage of the hydraulic press is 2000T; the specific process of the one-time forging is: the high-purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is a large deformation, and the deformation amount of each pass is 18%; the temperature of the high-temperature annealing treatment is 1230°C, and the holding time is 1h;

[0055] Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and after the secondary forging is completed, the high purity tantalum is subjected to medium temperature annealing; the specific process of the secondary forging is: the high purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is medium deformation, and the deformation amount of each pass is 13%; the temperature of the medium temperature annealing treatment is 1160°C, and the holding time is 1h;

[0056] Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and the high-purity tantalum is subjected to low-temperature annealing treatment after the three-time forging is completed; the specific process of the three-time forging is: the high-purity tantalum is upset for multiple times along the axial direction to 1 / 2 of the original height, and then drawn for multiple times to the original height, each of the upsetting and drawing passes is a small deformation, and the deformation amount of each pass is 9%; the temperature of the low-temperature annealing treatment is 1030°C, and the holding time is 1h;

[0057] Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross-rolled on the rolling mill, and after the one cross rolling is completed, the high purity tantalum is subjected to medium temperature short time annealing to obtain an intermediate target blank; the roller diameter of the rolling mill is 500mm; the specific process of the one cross rolling is as follows: after each rolling pass is completed, the high purity tantalum is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a larger deformation, the deformation amount of the pass is 15%, and the total deformation amount of the one cross rolling is 45%; the temperature of the medium temperature short time annealing treatment is 1150°C, and the holding time is 20min;

[0058] Step 5, cutting the intermediate target blank: perform wire cutting along 1 / 2 of the thickness of the intermediate target blank in step 4, and divide the intermediate target blank into two groups evenly; during the wire cutting process, the cutting surface should be smooth and free of burrs;

[0059] Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and after the secondary cross rolling is completed, the intermediate target blank is subjected to low-temperature long-time annealing treatment to obtain a tantalum target blank; the specific process of the secondary cross rolling is as follows: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal for the next rolling pass, each pass is a small deformation, the deformation amount of the pass is 9%, and the total deformation amount of the secondary cross rolling is 53%; the temperature of the low-temperature long-time annealing treatment is 1060°C, and the insulation time is 2h; the diameter of the tantalum target blank is ≥500mm, the thickness is ≥10mm, and the proportion of defects and waste is <5%.

[0060] The proportions of {100} texture and {111} texture of the tantalum target blank prepared in Example 3 are shown in Table 1. It can be seen that the proportion of {100} texture is 42% and the proportion of {111} texture is 18%. The average grain size statistics of the tantalum target blank are shown in Figure 2 , it can be seen that the average grain size is 47.6μm. The {100} orientation and {111} orientation of the tantalum target blank are evenly distributed in the edge and core along the thickness direction, and no texture band is generated. The prepared tantalum target blank can meet the sputtering coating requirements of 12-inch wafers.

[0061] Example 4

[0062] This embodiment provides a method for preparing a tantalum target blank with a highly uniform texture, comprising the following steps:

[0063] Step 1, one-time forging: the high-purity tantalum after electron beam melting is forged once on a hydraulic press, and the high-purity tantalum is subjected to high-temperature annealing after the one-time forging is completed; the purity of the high-purity tantalum is 5N; the tonnage of the hydraulic press is 2000T; the specific process of the one-time forging is: the high-purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is a large deformation, and the deformation amount of each pass is 20%; the temperature of the high-temperature annealing treatment is 1250°C, and the holding time is 1h;

[0064] Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and after the secondary forging is completed, the high purity tantalum is subjected to medium temperature annealing; the specific process of the secondary forging is: the high purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is medium deformation, and the deformation amount of each pass is 13%; the temperature of the medium temperature annealing treatment is 1150°C, and the holding time is 1h;

[0065] Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and the high-purity tantalum is subjected to low-temperature annealing treatment after the three-time forging is completed; the specific process of the three-time forging is: the high-purity tantalum is upset for multiple times along the axial direction to 1 / 2 of the original height, and then drawn for multiple times to the original height, each of the upsetting and drawing passes is a small deformation, and the deformation amount of each pass is 8%; the temperature of the low-temperature annealing treatment is 1080°C, and the holding time is 1h;

[0066] Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross-rolled on the rolling mill, and after the one cross rolling is completed, the high purity tantalum is subjected to medium temperature short time annealing to obtain an intermediate target blank; the roller diameter of the rolling mill is 500mm; the specific process of the one cross rolling is as follows: after each rolling pass is completed, the high purity tantalum is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a larger deformation, the deformation amount of the pass is 15%, and the total deformation amount of the one cross rolling is 48%; the temperature of the medium temperature short time annealing treatment is 1160°C, and the holding time is 40min;

[0067] Step 5, cutting the intermediate target blank: perform wire cutting along 1 / 2 of the thickness of the intermediate target blank in step 4, and divide the intermediate target blank into two groups evenly; during the wire cutting process, the cutting surface should be smooth and free of burrs;

[0068] Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and after the secondary cross rolling is completed, the intermediate target blank is subjected to low-temperature long-time annealing treatment to obtain a tantalum target blank; the specific process of the secondary cross rolling is as follows: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal for the next rolling pass, each pass is a small deformation, the deformation amount of the pass is 10%, and the total deformation amount of the secondary cross rolling is 60%; the temperature of the low-temperature long-time annealing treatment is 1080°C, and the insulation time is 2h; the diameter of the tantalum target blank is ≥500mm, the thickness is ≥10mm, and the proportion of defects and waste is <5%.

[0069] The proportions of {100} texture and {111} texture of the tantalum target blank prepared in Example 4 are shown in Table 1. It can be seen that the proportion of {100} texture is 37%, and the proportion of {111} texture is 23%. The average grain size statistics of the tantalum target blank are shown in Figure 2 , it can be seen that the average grain size is 52.1μm. The {100} orientation and {111} orientation of the tantalum target blank are evenly distributed in the edge and core along the thickness direction, and no texture band is generated. The prepared tantalum target blank can meet the sputtering coating requirements of 12-inch wafers.

[0070] Example 5

[0071] This embodiment provides a method for preparing a tantalum target blank with a highly uniform texture, comprising the following steps:

[0072] Step 1, one-time forging: the high-purity tantalum after electron beam melting is forged once on a hydraulic press, and the high-purity tantalum is subjected to high-temperature annealing after the one-time forging is completed; the purity of the high-purity tantalum is 5N; the tonnage of the hydraulic press is 2000T; the specific process of the one-time forging is: the high-purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is a large deformation, and the deformation amount of each pass is 19%; the temperature of the high-temperature annealing treatment is 1280°C, and the holding time is 1h;

[0073] Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and after the secondary forging is completed, the high purity tantalum is subjected to medium temperature annealing; the specific process of the secondary forging is: the high purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is medium deformation, and the deformation amount of each pass is 12%; the temperature of the medium temperature annealing treatment is 1160°C, and the holding time is 1h;

[0074] Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and the high-purity tantalum is subjected to low-temperature annealing treatment after the three-time forging is completed; the specific process of the three-time forging is: the high-purity tantalum is upset multiple times along the axial direction to 1 / 2 of the original height, and then drawn multiple times to the original height, each of the upsetting and drawing passes is a small deformation, and the deformation amount of each pass is 10%; the temperature of the low-temperature annealing treatment is 1080°C, and the holding time is 1h;

[0075] Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross-rolled on the rolling mill, and after the one cross rolling is completed, the high purity tantalum is subjected to medium temperature short time annealing to obtain an intermediate target blank; the roller diameter of the rolling mill is 600mm; the specific process of the one cross rolling is as follows: after each rolling pass is completed, the high purity tantalum is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a larger deformation, the deformation amount of the pass is 16%, and the total deformation amount of the one cross rolling is 50%; the temperature of the medium temperature short time annealing treatment is 1160°C, and the holding time is 40min;

[0076] Step 5, cutting the intermediate target blank: perform wire cutting along 1 / 2 of the thickness of the intermediate target blank in step 4, and divide the intermediate target blank into two groups evenly; during the wire cutting process, the cutting surface should be smooth and free of burrs;

[0077] Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and after the secondary cross rolling is completed, the intermediate target blank is subjected to low-temperature long-time annealing treatment to obtain a tantalum target blank; the specific process of the secondary cross rolling is as follows: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal for the next rolling pass, each pass is a small deformation, the deformation amount of the pass is 10%, and the total deformation amount of the secondary cross rolling is 60%; the temperature of the low-temperature long-time annealing treatment is 1060°C, and the insulation time is 2.5h; the diameter of the tantalum target blank is ≥500mm, the thickness is ≥10mm, and the proportion of defects and waste is <5%.

[0078] The proportions of {100} texture and {111} texture of the tantalum target blank prepared in Example 5 are shown in Table 1. It can be seen that the proportion of {100} texture is 36%, and the proportion of {111} texture is 20%. The average grain size statistics of the tantalum target blank are shown in Figure 2 , it can be seen that the average grain size is 45.8μm. The {100} orientation and {111} orientation of the tantalum target blank are evenly distributed in the edge and core along the thickness direction, and no texture band is generated. The prepared tantalum target blank can meet the sputtering coating requirements of 12-inch wafers.

[0079] Example 6

[0080] This embodiment provides a method for preparing a tantalum target blank with a highly uniform texture, comprising the following steps:

[0081] Step 1, one-time forging: the high-purity tantalum after electron beam melting is forged once on a hydraulic press, and the high-purity tantalum is subjected to high-temperature annealing after the one-time forging; the purity of the high-purity tantalum is 5N; the tonnage of the hydraulic press is 2000T; the specific process of the one-time forging is: the high-purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is a large deformation, and the deformation amount of each pass is 20%; the temperature of the high-temperature annealing treatment is 1280°C, and the holding time is 1h;

[0082] Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and after the secondary forging is completed, the high purity tantalum is subjected to medium temperature annealing; the specific process of the secondary forging is: the high purity tantalum is subjected to multiple upsettings along the axial direction to 1 / 2 of the original height, and then is subjected to multiple drawing to the original height, each of the upsetting and drawing is medium deformation, and the deformation amount of each pass is 13%; the temperature of the medium temperature annealing treatment is 1180°C, and the holding time is 1h;

[0083] Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and the high-purity tantalum is subjected to low-temperature annealing treatment after the three-time forging is completed; the specific process of the three-time forging is: the high-purity tantalum is upset for multiple times along the axial direction to 1 / 2 of the original height, and then drawn for multiple times to the original height, each of the upsetting and drawing is a small deformation, and the deformation amount of each pass is 10%; the temperature of the low-temperature annealing treatment is 1060°C, and the holding time is 1h;

[0084] Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross-rolled on the rolling mill, and after the one cross rolling is completed, the high purity tantalum is subjected to medium temperature short time annealing to obtain an intermediate target blank; the roller diameter of the rolling mill is 600mm; the specific process of the one cross rolling is as follows: after each rolling pass is completed, the high purity tantalum is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a larger deformation, the deformation amount of the pass is 16%, and the total deformation amount of the one cross rolling is 50%; the temperature of the medium temperature short time annealing treatment is 1180°C, and the holding time is 30min;

[0085] Step 5, cutting the intermediate target blank: perform wire cutting along 1 / 2 of the thickness of the intermediate target blank in step 4, and divide the intermediate target blank into two groups evenly; during the wire cutting process, the cutting surface should be smooth and free of burrs;

[0086] Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and after the secondary cross rolling is completed, the intermediate target blank is subjected to low-temperature long-time annealing treatment to obtain a tantalum target blank; the specific process of the secondary cross rolling is as follows: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal for the next rolling pass, each pass is a small deformation, the deformation amount of the pass is 10%, and the total deformation amount of the secondary cross rolling is 60%; the temperature of the low-temperature long-time annealing treatment is 1080°C, and the insulation time is 2.5h; the diameter of the tantalum target blank is ≥500mm, the thickness is ≥10mm, and the proportion of defects and waste is <5%.

[0087] The proportions of {100} texture and {111} texture of the tantalum target blank prepared in Example 6 are shown in Table 1. It can be seen that the proportion of {100} texture is 39%, and the proportion of {111} texture is 24%. The average grain size statistics of the tantalum target blank are shown in Figure 2 , it can be seen that the average grain size is 47.2μm. The {100} orientation and {111} orientation of the tantalum target blank are evenly distributed in the edge and core along the thickness direction, and no texture band is generated. The prepared tantalum target blank can meet the sputtering coating requirements of 12-inch wafers.

[0088] Table 1 The proportion of {100} texture and {111} texture of tantalum target blanks prepared in Examples 1 to 6

[0089] {100}Texture ratio {111} Texture ratio Example 1 40％ 21％ Example 2 44％ 26％ Example 3 42％ 18％ Example 4 37％ 23％ Example 5 36％ 20％ Example 6 39％ 24％

[0090] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a tantalum target blank with a highly uniform texture, characterized in that: The following steps are involved: Step 1: One-time forging: The high-purity tantalum after electron beam melting is forged on a hydraulic press, and then subjected to high-temperature annealing treatment; Step 2, secondary forging: the high purity tantalum after high temperature annealing in step 1 is subjected to secondary forging, and then subjected to medium temperature annealing; Step 3, three-time forging: the high-purity tantalum after the medium-temperature annealing treatment in step 2 is forged three times, and then subjected to low-temperature annealing treatment; Step 4, one cross rolling: the high purity tantalum after low temperature annealing in step 3 is cross rolled on a rolling mill, and then subjected to medium temperature short time annealing to obtain an intermediate target blank; Step 5, cutting the intermediate target blank: perform wire cutting along 1 / 2 of the thickness of the intermediate target blank in step 4, and divide the intermediate target blank into two groups evenly; Step six, secondary cross rolling: the intermediate target blank cut in step five is subjected to secondary cross rolling, and then subjected to low temperature and long time annealing treatment to obtain a tantalum target blank.

2. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The purity of the high-purity tantalum in step 1 is 5N, and the tonnage of the hydraulic press is 2000T.

3. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The specific process of the one forging in step one includes: performing multiple upsetting of the high-purity tantalum along the axial direction to 1 / 2 of the original height, and then performing multiple drawing to the original height, wherein each of the upsetting and drawing is a large deformation, and the deformation amount of each pass is 18% to 20%; the temperature of the high-temperature annealing treatment in step one is 1220°C to 1280°C, and the holding time is 1h.

4. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The specific process of the secondary forging described in step 2 includes: performing multiple upsetting passes on the high-purity tantalum along the axial direction to 1 / 2 of the original height, and then performing multiple drawing passes to the original height, wherein each of the upsetting and drawing passes is a medium deformation, and the deformation amount of each pass is 12% to 13%; the temperature of the medium-temperature annealing treatment described in step 2 is 1120°C to 1180°C, and the holding time is 1h.

5. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The specific process of the three forgings in step three includes: performing multiple upsetting of the high-purity tantalum along the axial direction to 1 / 2 of the original height, and then performing multiple drawing to the original height, wherein each of the upsetting and drawing is a small deformation, and the deformation amount of each pass is 8% to 10%; the temperature of the low-temperature annealing treatment in step three is 1020°C to 1080°C, and the holding time is 1h.

6. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The roller diameter of the rolling mill described in step 4 is 400mm to 600mm.

7. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The specific process of the cross rolling described in step 4 includes: after each rolling pass is completed, the high-purity tantalum is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a large deformation, the deformation amount is 14% to 16%, and the total deformation amount of one cross rolling is 45% to 50%; the temperature of the medium-temperature short-time annealing treatment described in step 4 is 1120°C to 1180°C, and the insulation time is 20min to 40min.

8. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: During the wire cutting process described in step 5, the cutting surface should be smooth and free of burrs.

9. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The specific process of the secondary cross rolling described in step six includes: after each rolling pass is completed, the intermediate target blank is rotated 90° clockwise along the normal direction for the next rolling pass, each pass is a small deformation, the deformation amount is 8% to 10%, and the total deformation amount of the secondary cross rolling is 50% to 60%; the temperature of the low-temperature long-time annealing treatment described in step six is ​​1020℃ to 1080℃, and the insulation time is 1.5h to 2.5h.

10. The method for preparing a tantalum target blank with a highly uniform texture according to claim 1, characterized in that: The tissue texture of the tantalum target blank described in step six is ​​evenly distributed, the average grain size is ≤60μm, the {100} texture accounts for ≥35%, and the {111} texture accounts for ≤30%; the diameter of the tantalum target blank is ≥500mm and the thickness is ≥10mm.

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