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CN-116815138-B - Cobalt ruthenium target material and preparation method thereof

CN116815138BCN 116815138 BCN116815138 BCN 116815138BCN-116815138-B

Abstract

The invention relates to the technical field of semiconductors and discloses a cobalt ruthenium target material and a preparation method thereof, wherein a cobalt ingot with purity of 2N8 (99.8%) and a ruthenium ingot with purity of 3N (99.9%) are purified through vacuum distillation and arc melting to obtain a high-purity 4N (99.99%) cobalt ingot and a high-purity 4N (99.99%) ruthenium ingot, and then a rotary hot rolling process is adopted to obtain the cobalt ruthenium target material with uniform grain size and high grain orientation degree, so that the problems of uneven grain size, disordered grain orientation and the like of the target material prepared by the traditional rolling process are overcome. The preparation method has the advantages of simple preparation process, capability of greatly reducing the production period and the production cost, and suitability for mass production.

Inventors

  • LI XINRAN
  • WANG YONGKANG
  • JU YANPENG
  • WANG YONGCHAO
  • ZHAO ZELIANG
  • CHEN YUANBO
  • WANG HONGBO
  • ZHANG YAMENG
  • WANG TIANHUI
  • LIU BO

Assignees

  • 河南东微电子材料有限公司

Dates

Publication Date
20260508
Application Date
20230712

Claims (6)

  1. 1. The preparation method of the cobalt ruthenium target is characterized by comprising the following steps: Step 1, performing primary vacuum distillation on a cobalt ingot with the purity of 2N8 (99.8%) in a vacuum distillation furnace, performing secondary vacuum distillation on the cobalt ingot subjected to primary distillation, and performing vacuum arc melting on the cobalt ingot in an arc melting furnace to obtain a high-purity 4N (99.99%) cobalt ingot; step 2, vacuum distilling the ruthenium ingot with the purity of 3N (99.9%) in a vacuum distillation furnace, and then vacuum arc smelting the distilled ruthenium ingot in an arc smelting furnace to obtain a 4N (99.99%) ruthenium ingot with high purity; Step 3, respectively taking cobalt ingots and ruthenium ingots with the purity of 4N, mixing, and then carrying out vacuum smelting to obtain cobalt-ruthenium alloy liquid, and injecting the cobalt-ruthenium alloy liquid into a disc-shaped graphite die to obtain high-purity cobalt-ruthenium alloy round ingots; Step 4, carrying out multiple-time rotary hot rolling on the cobalt-ruthenium alloy round ingot obtained in the step3, wherein the rotation angle is 120 degrees, and rolling for 2-3 weeks to obtain a cobalt-ruthenium alloy plate blank; Step 5, annealing the cobalt-ruthenium alloy plate blank to obtain a cobalt-ruthenium target; in the step 4, after each rolling pass, the rolling direction is rotated by 120 degrees to perform next rolling, wherein each rolling pass is 1 week, and the rolling is 2-3 weeks; The total deformation of the cobalt-ruthenium alloy slab after hot rolling in the step 4 is 60% -80%, the grain size is 120+/-20 mu m, and the grain ratio of the grain orientation (0001) plane is 40% -60%; And in the step 4, the hot rolling temperature is 950-1350 ℃ and the hot rolling time is 8-20 min.
  2. 2. The method for preparing a cobalt ruthenium target according to claim 1, wherein the temperature of the primary distillation in the step 1 is 1500-1550 ℃, the vacuum degree is 1×10 -2 Pa, the temperature of the secondary distillation is 1550-1600 ℃, the vacuum degree is 1×10 -2 Pa, and the vacuum degree of arc melting is 1×10 -3 Pa.
  3. 3. The method for preparing a cobalt ruthenium target according to claim 1, wherein the distillation temperature in the step 2 is 2600-2700 ℃, the vacuum degree is 1×10 -3 Pa, and the vacuum degree of arc melting is 1×10 -3 Pa.
  4. 4. The method for preparing the cobalt-ruthenium target according to claim 1, wherein in the step 3, the atomic ratio of cobalt and ruthenium is (50% -80%) (20% -50%).
  5. 5. The method for preparing a cobalt ruthenium target according to claim 1, wherein the vacuum melting temperature in the step 3 is 1600-2000 ℃, the melting time is 2-4 hours, and the vacuum degree is 1 x 10 -3 Pa.
  6. 6. The method for preparing a cobalt ruthenium target according to claim 1, wherein the annealing temperature in the step 5 is 800-1000 ℃ and the annealing time is 2-4 hours.

Description

Cobalt ruthenium target material and preparation method thereof Technical Field The invention relates to the technical field of semiconductors, in particular to a cobalt ruthenium target and a preparation method thereof. Background The semiconductor sputtering target materials such as cobalt, ruthenium and the like are widely applied to the fields of information storage, semiconductor chips and the like, physical vapor deposition technology is adopted, gaseous ions are accelerated to bombard the target materials under high pressure, atoms of the target materials are sputtered, thin film deposition is achieved on the surface of a silicon wafer, and the requirements for the sputtering target materials such as cobalt, ruthenium and the like are rapidly increased along with rapid development of the semiconductor industry in recent years. The performance of a semiconductor integrated circuit metal film is primarily dependent on the grain size and grain orientation of the target. At present, the grain size and grain orientation of the target material are mainly adjusted and controlled through homogenization treatment, thermomechanical processing, recrystallization annealing and other processes. The purity requirement of cobalt for the cobalt-based sputtering target material for the semiconductor is more than 4N (99.99%), high-purity cobalt powder is usually sintered into blocks, then high-purity cobalt ingots are obtained through a high-vacuum electron beam smelting furnace, and finally plastic deformation, annealing and back plate welding are carried out, so that a finished product is obtained, but the problems of uneven grain size, disordered grain orientation and the like of the target material prepared by the traditional rolling process can occur, and therefore, the novel efficient preparation method is adopted, and the cobalt-ruthenium target material with uniform grain size and high grain orientation degree has important significance. Disclosure of Invention The invention solves the technical problems of uneven grain size, disordered grain orientation and the like of a target prepared by the traditional rolling process, and the cobalt ruthenium target with uniform grain size and high grain orientation degree can be obtained by adopting a rotary hot rolling method. The technical scheme of the invention is as follows: the preparation method of the cobalt ruthenium target comprises the following steps: and step 1, performing primary vacuum distillation on a cobalt ingot with the purity of 2N8 (99.8%) in a vacuum distillation furnace, performing secondary vacuum distillation on the cobalt ingot subjected to primary distillation, and performing vacuum arc melting on the cobalt ingot in an arc melting furnace to obtain a high-purity 4N (99.99%) cobalt ingot. And 2, carrying out vacuum distillation on the ruthenium ingot with the purity of 3N (99.9%) in a vacuum distillation furnace, and then carrying out vacuum arc melting on the distilled ruthenium ingot in an arc melting furnace to obtain the 4N (99.99%) ruthenium ingot with high purity. And 3, respectively taking cobalt ingots and ruthenium ingots with the purity of 4N, mixing, and then carrying out vacuum smelting to obtain cobalt-ruthenium alloy liquid, and injecting the cobalt-ruthenium alloy liquid into a disc-shaped graphite die to obtain high-purity cobalt-ruthenium alloy round ingots. And 4, carrying out multiple-time rotary hot rolling on the cobalt-ruthenium alloy round ingot obtained in the step 1, wherein the rotation angle is 120 degrees, and rolling for 2-3 weeks to obtain a cobalt-ruthenium alloy plate blank. And 5, annealing the cobalt-ruthenium alloy plate blank to obtain the cobalt-ruthenium target. Preferably, the temperature of the primary distillation in the step 1 is 1500-1550 ℃, the vacuum degree is 1 multiplied by 10 -2 Pa, the temperature of the secondary distillation is 1550-1600 ℃, the vacuum degree is 1 multiplied by 10 -2 Pa, and the vacuum degree of arc melting is 1 multiplied by 10 -3 Pa. Preferably, the distillation temperature in the step 2 is 2600-2700 ℃, the vacuum degree is 1×10 -3 Pa, and the vacuum degree of arc melting is 1×10 -3 Pa. Preferably, in the step 3, the atomic ratio of cobalt and ruthenium is (50% -80%) (20% -50%). Preferably, the vacuum melting temperature in the step 3 is 1600-2000 ℃, the melting time is 2-4 h, and the vacuum degree is 1×10 -3 Pa. Preferably, in the step 4, the rolling direction is rotated by 120 ° for next rolling after each rolling pass, and each rolling pass is 1 week for three times, and the rolling is 2-3 weeks. Preferably, the total deformation of the cobalt-ruthenium alloy slab after hot rolling in the step 4 is 60% -80%, the grain size is 120+ -20 μm, and the grain ratio of the grain orientation (0001) plane is 40% -60%. Preferably, the hot rolling temperature in the step 4 is 950-1350 ℃ and the hot rolling time is 8-20 min. Preferably, the annealing temperature in the step 5 is 800-10