Shaping method of semiconductor metal rolling target material

Abstract

The invention discloses a shaping method for a semiconductor metal rolling target material, which is characterized in that for rolling target materials of different materials, corresponding shaping methods are selected for shaping processing according to the bending strength of the materials; according to the method, the ideal planeness is achieved by providing a multi-time shaping method for the rolled target blank, and the internal stress is released by adding intermediate annealing and other methods during multi-time shaping for a material with relatively high bending strength, so that the plasticity of the target material is improved, the shaping quality is ensured, the needed planeness is achieved, and secondary deformation is prevented; and cracking caused by overlarge deformation of one-time shaping is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of target material production methods, and in particular to a method for shaping semiconductor metal rolling target materials. Background Art

[0002] In today's semiconductor industry, target materials play a very important role. Target materials are the sputtering sources that form thin films on the surface of substrates or workpieces through the sputtering coating process in physical vapor deposition. The sputtering performance of target materials is also continuously improved as the requirements for product coating quality continue to improve. High-purity metal target materials are obtained through multiple process flows such as smelting, forging, rolling, shaping, heat treatment, welding and machining.

[0003] For semiconductor circular aluminum targets, copper targets, titanium targets and tantalum targets, they will bend and deform with the rollers during the rolling process. It is necessary to use pressure shaping to make the target material's flatness meet machining requirements and reduce material machining losses. In addition to adjusting the flatness, pressure shaping also requires stress release to prevent secondary deformation caused by stress release during subsequent processing. Therefore, shaping of the target material after rolling is an important process, which even directly affects product quality.

[0004] However, different target materials have different mechanical properties, and the corresponding shaping processes are also different. The current shaping process has many problems: 1. For some materials with high bending strength, one shaping cannot achieve the required flatness, and some even cannot achieve the required flatness after multiple shaping; 2. Secondary deformation may also occur during the processing after shaping; 3. For some brittle materials, the deformation amount of one shaping is too large during the shaping process, and cracking is likely to occur if the deformation exceeds the limit, which directly leads to scrapping. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a shaping method for semiconductor metal rolling targets. The present invention provides different shaping methods for rolling target blanks with different material properties, improves the target shaping effect, and improves the target quality and yield rate.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a shaping method for semiconductor metal rolling target material, for rolling targets of different materials, the corresponding shaping method is selected for shaping processing according to the bending strength and plasticity characteristics of the material;

[0007] Shaping method 1, shaping a semiconductor metal rolling target with a bending strength of 150-350MPa, firstly performing a pre-shaping treatment on the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is 45-100KN, the holding time is 10-15min, and the shaping amount of the pre-shaping pressurization treatment is controlled at 25-35%;

[0008] After the pressure is released, a secondary pressure holding treatment is performed to pressurize the circular semiconductor metal rolling target for the second time. The pressure of the secondary pressure holding treatment is 50-105KN, the pressure holding time is 10-15min, and the shaping amount of the secondary pressure holding treatment is controlled at 35%-45%;

[0009] After unloading the pressure, three pressure-holding treatments are performed, and the semiconductor metal rolling target is pressurized for the third time. The pressure of the three pressure-holding treatments is 55-110KN, the time is 10-15min, and the pressure-holding shaping amount is controlled at 25%-35%. After the semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m, the three pressure-holding treatments are stopped to complete the processing;

[0010] Shaping method 2, shaping the semiconductor metal rolling target with a bending strength of 350-650MPa, first pre-shaping the semiconductor metal rolling target, first pre-shaping the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is 100-180KN, the pressure holding time is 10-15min, and the pre-shaping amount is controlled at 25-35%,

[0011] Then, the semiconductor metal rolling target is heated at a temperature of 200-450°C for 20-40 minutes, and finally, a hot pressing treatment is performed while hot, and the pressure of the hot pressing treatment is 105-185KN for 10-15 minutes. The hot shaping amount is controlled at 65%-75%, and the semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m, and then the hot pressing treatment is stopped to complete the processing;

[0012] Shaping method 3, shaping the semiconductor metal rolling target with a bending strength of more than 650MPa, first pre-shaping the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is ≥180KN, the holding time is 10-15min, the pre-shaping amount is controlled at 15-25%, and then the target is heated to relieve stress, the heating temperature is 400-700℃, the time is 30-50min, and then hot holding treatment is performed while hot, the hot holding pressure treatment pressure is ≥185KN, the holding time is 10-15min, and the shaping amount is controlled at 45%-55%,

[0013] The target is shaped to a flatness of ≤1mm and then subjected to intermediate annealing treatment. The annealing temperature of the intermediate annealing treatment is 400-700°C and the intermediate annealing time is 40-60min.

[0014] Finally, the secondary heat holding treatment is performed again while hot, and the pressure of the heat holding treatment is ≥190KN. The semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m while hot, and then the secondary heat holding treatment is stopped. The shaping amount is controlled at 25%-35%, and the processing is completed;

[0015] Shaping method 4, a semiconductor metal rolling target with a bending strength less than 150MPa is shaped by direct pressure shaping. The semiconductor metal rolling target with a bending strength less than 150MPa is placed on the workbench of a hydraulic press, and the semiconductor metal rolling target is gradually pressurized by the pressure head of the hydraulic press. The shaping pressure applied by the pressure head is determined by the following pressure control formula: shaping pressure = σ*4W / L, σ is the bending strength, L is the span, and W is the section modulus of the sample. According to standard YB / T5349-2014, W = bh 2 / 6, b is the line width of the contact between the material and the pressure head, h is the material thickness, the material is in the shape of a round pancake, when the shaping pressure is maximum, b = material diameter D, span L is equal to D, until the target flatness of the semiconductor metal rolling target is ≤0.3mm / m, the shaping amount is 100%, and the processing is completed.

[0016] In a further technical solution, in the shaping method 2, the heat-holding treatment while hot is performed within 30 seconds after the heat treatment is completed. In the shaping method 3, the heat-holding treatment while hot is performed within 30 seconds after the heat treatment is completed; and the secondary heat-holding treatment while hot is performed within 30 seconds after the intermediate annealing treatment is completed.

[0017] In a further technical solution, the shaping method 4, according to the rolling characteristics, the maximum concave-convex point of the semiconductor metal rolling target is 1 / 2 diameter of the semiconductor metal rolling target, the pressure calculation selects the thickness of the semiconductor metal rolling target as 20mm, the shaping pressure is greater than the calculated value, the shaping pressure is determined by the pressure control formula to be 40kN, the shaping pressure is increased to 45KN pressure value and then maintained for 5-10 minutes, the shaping amount is 100%, the target flatness of the metal rolling target is ≤0.3mm / m, and the processing is completed.

[0018] Compared with the prior art, the advantages of the present invention are as follows: the present invention provides a method of multiple shaping for rolling target blanks to achieve ideal flatness, and for materials that are difficult to shape, intermediate annealing and other methods are added between multiple shapings to release internal stress, improve the plasticity of the target material, ensure the shaping quality, achieve the required flatness, prevent secondary deformation, and prevent cracking caused by excessive deformation in one shaping.

[0019] In addition, for materials with poor plasticity, in order to prevent excessive shaping in one time, which may cause target material cracking under cold working hardening conditions, or for materials with high bending strength, it is difficult to shape them to the required flatness in one time, or they may deform after shaping, multiple shaping methods are adopted to achieve the ideal flatness, and intermediate annealing is added between multiple shaping to release internal stress, improve target material plasticity, and ensure shaping quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the cold pressurization shaping of the target material according to the present invention.

[0021] Markings in the figure:

[0022] 1. Plastic surgery platform

[0023] 2. Target

[0024] 3. Hydraulic press head DETAILED DESCRIPTION

[0025] A shaping method for semiconductor metal rolling target material, for rolling target materials of different materials, the corresponding shaping method is selected for shaping processing according to the bending strength and plasticity characteristics of the material;

[0026] Shaping method 1, shaping a semiconductor metal rolling target with a bending strength of 150-350MPa, firstly performing a pre-shaping treatment on the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is 45-100KN, the holding time is 10-15min, and the shaping amount of the pre-shaping pressurization treatment is controlled at 25-35%;

[0027] After the pressure is released, a secondary pressure holding treatment is performed to pressurize the semiconductor metal rolling target for the second time. The pressure of the secondary pressure holding treatment is 50-105KN, the pressure holding time is 10-15min, and the shaping amount of the secondary pressure holding treatment is controlled at 35%-45%;

[0028] After the pressure is released, three pressure-holding treatments are performed, and the semiconductor metal rolling target is pressurized for the third time. The pressure of the three pressure-holding treatments is 55-110KN, the time is 10-15min, and the pressure-holding shaping amount is controlled at 25%-35%. After the semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m, the three pressure-holding treatments are stopped to complete the processing;

[0029] Shaping method 2, shaping the semiconductor metal rolling target with a bending strength of 350-650MPa, first pre-shaping the semiconductor metal rolling target, first pre-shaping the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is 100-180KN, the pressure holding time is 10-15min, and the pre-shaping amount is controlled at 25-35%,

[0030] Then, the semiconductor metal rolling target is heat treated at a temperature of 200-450°C and a time of 20-40 minutes. Within 30 seconds after the heat treatment is completed, a hot holding pressure treatment is performed while hot. The pressure of the hot holding pressure treatment is 105-185KN and the holding pressure is 10-15 minutes. The hot shaping amount is controlled at 65%-75%. After the semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m, the hot holding pressure treatment is stopped to complete the processing;

[0031] Shaping method 3, shaping the semiconductor metal rolling target with a bending strength of ≥650MPa, first pre-shaping the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is ≥180KN, the holding time is 10-15min, the pre-shaping amount is controlled at 15-25%, and then the target is heat treated at a temperature of 400-700℃ and a time of 30-50min. After the heat treatment is completed, hot holding treatment is performed while hot within 30 seconds, the pressure of the hot holding treatment is ≥185KN, the holding time is 10-15min, and the shaping amount is controlled at 45%-55%.

[0032] The target is shaped to a flatness of ≤1mm and then subjected to intermediate annealing treatment. The annealing temperature of the intermediate annealing treatment is 400-700°C and the intermediate annealing time is 40-60min.

[0033] After completing the intermediate annealing treatment, a secondary heat holding treatment is performed while hot within 30 seconds. The semiconductor metal rolling target is shaped while hot at a pressure of ≥190KN to a flatness of ≤0.3mm / m, and then the secondary heat holding treatment is stopped. The shaping amount is controlled at 25%-35% to complete the processing.

[0034] Shaping method 4, for semiconductor metal rolling targets with a bending strength of less than 150MPa, direct pressure shaping is used to shape the semiconductor metal rolling targets with a bending strength of less than 150MPa. The semiconductor metal rolling targets with a bending strength of less than 150MPa are placed on the workbench of a hydraulic press, and the semiconductor metal rolling targets are gradually pressurized by the pressure head of the hydraulic press. The shaping pressure applied by the pressure head is determined by the following pressure control formula: shaping pressure = σ*4W / L, referring to standard YB / T5349-2014, where σ is the bending strength, L is the span, and W is the section modulus of the specimen, where W = bh2 / 6, b is the line width of the contact between the material and the pressure head. When the shaping pressure is the largest, b = material diameter D. At this time, the span L is also equal to D. h is the material thickness. The material shape of the semiconductor metal rolling target is a round pancake. According to the rolling characteristics, the maximum concave and convex point of the semiconductor metal rolling target is close to 1 / 2 of the diameter. The pressure calculation in this article selects the target thickness of 20mm, and the shaping pressure needs to be greater than the calculated value. The shaping pressure is determined to be 40kN by the pressure control formula. After the shaping pressure increases to 45KN, the pressure is maintained for 10-15min until the target flatness of the semiconductor metal rolling target is ≤0.3mm / m, the shaping amount is 100%, and the processing is completed.

[0035] The present invention provides a method for multiple shaping of rolled target blanks to achieve ideal flatness. For materials with greater bending strength, intermediate annealing and other methods are added between multiple shaping to release internal stress, improve the plasticity of the target material, ensure the shaping quality, achieve the required flatness, prevent secondary deformation, and prevent cracking caused by excessive deformation in one shaping.

[0036] 1. For the rolling target blank, the method of pre-shaping + final shaping and multiple shaping can prevent excessive shaping at one time and avoid cracking caused by cold working hardening state.

[0037] 2. Reshaping after heat treatment can release internal stress, improve material plasticity, and ensure that the flatness after shaping reaches ≤0.3mm / m. Reaching this flatness requirement can improve the utilization rate of materials during machining.

[0038] 3. Designing different shaping methods according to the different bending strengths of aluminum, copper, titanium and tantalum can solve the problem of shaping cracking, the problem of secondary deformation in the subsequent processing process, and the situation where the bending strength is too high to be shaped.

[0039] Example 1

[0040] The aluminum target with a bending strength of 100Mpa and a thickness of 20mm was shaped. The flatness before shaping was 2mm / m. The aluminum target was directly cold-pressed with a cold pressing pressure of 30KN and maintained at pressure for 10min. It was directly shaped to a flatness of ≤0.3mm / m to complete the shaping process.

[0041] Example 2

[0042] The copper rolling target with a bending strength of 280MPa and a thickness of 20mm was shaped. The flatness before shaping was 4mm / m. It was pre-pressurized to 80KN and maintained for 10min to pre-shape it to a flatness of 2.8mm. After the pressure was released, it was re-pressurized to 85KN for a second time and maintained for 15min until the flatness was ≤1.2mm / m. After the pressure was released, it was re-pressurized to 90KN for a third time and maintained for 15min until the flatness was ≤0.3mm / m to complete the shaping process.

[0043] Example 3

[0044] The 20mm thick titanium rolled target with a bending strength of 550MPa was shaped. The flatness before shaping was 6mm / m. It was pre-shaped to a flatness of 4.2mm by pre-applying a pressure of 150KN and holding the pressure for 10min. The target was then heat treated at 350℃ for 30min. While hot, it was pressurized at 75KN for 15min until the flatness was ≤0.3mm / m to complete the shaping process.

[0045] Example 4

[0046] A 20mm thick rolled tantalum target with a bending strength of 710Mpa was shaped by pre-pressurizing it with 195KN and then maintaining the pressure for 10 minutes until the target flatness reached 6.4mm / m. The target was then heat treated at 550℃ for 40min, and then maintained under pressure at 200KN for 15min while hot, shaped to a flatness of ≤1.2mm. An intermediate annealing treatment was then performed at 650℃ for 50min, and then maintained under pressure at 205KN for 15min while hot, shaped to a flatness of ≤0.3mm / m to complete the shaping process.

[0047] Table 1 shows the data comparison of the targets prepared by the shaping methods of Examples 1 to 4.

[0048]

[0049] Table 1 - Data comparison table.

Claims

1. A method for shaping a semiconductor metal rolling target, characterized in that: For rolling targets of different materials, the corresponding shaping method is selected for shaping according to the bending strength and plasticity characteristics of the material; Shaping method 1, shaping a semiconductor metal rolling target with a bending strength of 150-350MPa, firstly performing a pre-shaping treatment on the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is 45-100KN, the holding time is 10-15min, and the shaping amount of the pre-shaping pressurization treatment is controlled at 25-35%; After the pressure is released, a secondary pressure holding treatment is performed to pressurize the circular semiconductor metal rolling target for the second time. The pressure of the secondary pressure holding treatment is 50-105KN, the pressure holding time is 10-15min, and the shaping amount of the secondary pressure holding treatment is controlled at 35%-45%; After unloading the pressure, three pressure-holding treatments are performed, and the semiconductor metal rolling target is pressurized for the third time. The pressure of the three pressure-holding treatments is 55-110KN, the time is 10-15min, and the pressure-holding shaping amount is controlled at 25%-35%. After the semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m, the three pressure-holding treatments are stopped to complete the processing; Shaping method 2, shaping the semiconductor metal rolling target with a bending strength of 350-650MPa, first pre-shaping the semiconductor metal rolling target, first pre-shaping the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is 100-180KN, the pressure holding time is 10-15min, and the pre-shaping amount is controlled at 25-35%, Then, the semiconductor metal rolling target is heated at a temperature of 200-450°C for 20-40 minutes, and finally, a hot pressing treatment is performed while hot, and the pressure of the hot pressing treatment is 105-185KN for 10-15 minutes. The hot shaping amount is controlled at 65%-75%, and the semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m, and then the hot pressing treatment is stopped to complete the processing; Shaping method 3, shaping the semiconductor metal rolling target with a bending strength of more than 650MPa, first pre-shaping the semiconductor metal rolling target, the pre-shaping treatment is to pre-pressurize the semiconductor metal rolling target, the pre-shaping pressure is ≥180KN, the holding time is 10-15min, the pre-shaping amount is controlled at 15-25%, and then the target is heated to relieve stress, the heating temperature is 400-700℃, the time is 30-50min, and then hot holding treatment is performed while hot, the hot holding pressure treatment pressure is ≥185KN, the holding time is 10-15min, and the shaping amount is controlled at 45%-55%, The target is shaped to a flatness of ≤1mm and then subjected to intermediate annealing. The annealing temperature of the intermediate annealing is 400-700°C and the intermediate annealing time is 40-60min. Finally, a secondary heat holding and pressing treatment is performed while hot. The pressure of the heat holding and pressing treatment is ≥190KN. The semiconductor metal rolling target is shaped to a flatness of ≤0.3mm / m while hot, and then the secondary heat holding and pressing treatment is stopped. The shaping amount is controlled at 25%-35% to complete the processing.

2. A method for shaping a semiconductor metal rolling target according to claim 1, characterized in that: The shaping method 2, The heat-maintaining and pressing treatment while hot is performed within 30 seconds after the heat treatment is completed.

3. The method for shaping a semiconductor metal rolling target according to claim 1, characterized in that: The shaping method 3, The heat-maintaining and pressing treatment while hot is performed within 30 seconds after the heat treatment is completed; The secondary heat-maintaining treatment while hot is performed within 30 seconds after the intermediate annealing treatment is completed.

4. A method for shaping a semiconductor metal rolling target according to any one of claims 1 to 3, characterized in that: Including shaping method 4, Shaping method 4, for semiconductor metal rolling targets with a bending strength of less than 150 MPa, direct pressure shaping is used to shape the semiconductor metal rolling targets with a bending strength of less than 150 MPa. The semiconductor metal rolling targets with a bending strength of less than 150 MPa are placed on the workbench of a hydraulic press, and the semiconductor metal rolling targets are gradually pressurized by the pressure head of the hydraulic press. The shaping pressure applied by the pressure head is determined by the following pressure control formula: shaping pressure = σ*4W / L, σ is the bending strength, L is the span, and W is the section modulus of the sample, until the target flatness of the semiconductor metal rolling target is ≤0.3 mm / m, the shaping amount is 100%, and the processing is completed.

5. A method for shaping a semiconductor metal rolling target according to claim 4, characterized in that: The shaping method 4, according to standard YB / T5349-2014, W = bh 2 / 6, b is the line width of contact between the material and the pressure head, h is the material thickness, the material is in the shape of a round pancake, when the shaping pressure is maximum, b = material diameter D, and the span L is equal to D.

6. A method for shaping a semiconductor metal rolling target according to claim 5, characterized in that: The shaping method 4, according to the rolling characteristics, the maximum concave-convex point of the semiconductor metal rolling target is 1 / 2 diameter of the semiconductor metal rolling target, the pressure calculation selects the thickness of the semiconductor metal rolling target as 20mm, the shaping pressure is greater than the calculated value, the shaping pressure is determined to be 40kN by the pressure control formula, the shaping pressure is increased to 45KN pressure value and then maintained for 5-10min, the shaping amount is 100%, the target flatness of the metal rolling target is ≤0.3mm / m, and the processing is completed.

Images