Pulse electron impact energy field nanoscale polishing method for 5N and 6N pure aluminum target materials

Abstract

The invention discloses a 5N and 6N pure aluminum target material pulse electron impact energy field nanoscale polishing method which comprises the following steps: placing a pretreated high-purity aluminum target material in a pulse electron impact energy field equipment cavity, vacuumizing, and carrying out nanoscale polishing on the aluminum target material by adopting a generated pulse electron impact energy field; the action range diameter of the pulse electron energy field is 100-400 [mu] m, the energy density is 1.2-2.5 J / cm < 2 >, the distribution path is equal-interval Archimedes spiral, the spiral interval is 80-320 [mu] m, and the interval is smaller than the action range diameter of the energy field; and the polished aluminum target material is subjected to cleaning treatment. According to the method, the aluminum target material is polished through the pulse electron impact energy field, precise polishing of the surface of the target material is achieved by regulating and controlling the distribution path, the energy density, the action range, the pulse width and other process parameters of the pulse electron impact energy field, the surface roughness of the aluminum target material is reduced to the nanoscale, and support is provided for improving the film forming uniformity of sputter coating.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aluminum target material polishing method, and particularly relates to a 5N and 6N pure aluminum target material pulsed electron impact energy field nanoscale polishing method. BACKGROUND

[0002] As a key material for semiconductor device manufacturing, the quality of thin film material will seriously affect the performance of the final semiconductor device. Sputtering is the most commonly used method for preparing thin films at present, and the film forming quality of sputtering is closely related to the performance of the sputtering target material. The internal structure and surface quality of the target material will affect the performance of the thin film. The flatness of the target surface will affect the sputtering rate, sputtering uniformity and other properties during the sputtering process, and then affect the thickness uniformity, conductivity, thermal conductivity and other properties of the obtained thin film.

[0003] Polishing is one of the key technologies for preparing target materials, and has an important influence on the surface performance of the target material. The commonly used target polishing methods at present include mechanical methods such as turning, grinding and mechanical polishing, and chemical mechanical polishing method (CMP) combining chemical corrosion and mechanical grinding. However, the process flow of the above methods is complex, the whole process is semi-automatic or manual operation, the polishing efficiency is low, and there are certain differences in the quality of the finished products obtained by polishing.

[0004] Due to the soft texture of high-purity aluminum metal, when the above two polishing methods are used, the roughness of the metal surface will not decrease but increase, and even serious surface damage will be caused. In addition, during the chemical mechanical polishing process, chemical reagents are used, which will also have a certain impact on the environment. SUMMARY

[0005] The present application provides a 5N and 6N pure aluminum target material pulsed electron impact energy field nanoscale polishing method, which polishes the aluminum target material by using a pulsed electron impact energy field. By adjusting the distribution path, energy density, action range and pulse width of the pulsed electron impact energy field, the precision polishing of the target surface can be realized, and the stability of the process is greatly improved.

[0006] In order to solve the above technical problems, the present application provides a 5N and 6N pure aluminum target material pulsed electron impact energy field nanoscale polishing method, which comprises the following steps:

[0007] S1, placing the pretreated aluminum target material in the cavity of the pulsed electron impact energy field device, and then polishing the aluminum target material by using a pulsed electron impact energy field after vacuumizing;

[0008] The action range diameter of the pulsed electron impact energy field is 100-400 mu m, and the energy density is 1.2-2.5 J / cm 2 ;

[0009] The distribution path of the pulsed electron impact energy field is an equidistant Archimedean spiral, which moves from the edge of the aluminum target to the center position of the aluminum target;

[0010] The spacing between adjacent lines in the Archimedean spiral is 80-320 mu m, and the spacing is smaller than the action range diameter of the pulsed electron impact energy field;

[0011] S2, the aluminum target polished by the electron beam is cleaned.

[0012] The present application utilizes pulsed electron impact energy field to polish the aluminum target, utilizes high-energy charged particles to bombard the target surface, generates high-temperature temperature field on the metal surface, causes the metal surface to melt instantaneously, the molten metal flows to the surrounding to fill the defects such as grooves and pores on the surface of the material, when the pulse ends, the surface metal liquid cools rapidly, thereby forming a smooth mirror structure, effectively reducing the roughness of the target surface; a reinforcing layer can also be formed on the surface of the aluminum target, improving the surface hardness of the target, and improving the microstructure of the target surface.

[0013] In addition, the present application can realize the precision polishing of the target surface by adjusting the process parameters such as the distribution path, energy density, action range and pulse time of the pulsed electron impact energy field. Compared with the traditional aluminum target polishing method, the pulsed electron impact energy field polishing process greatly improves the surface quality and stability of the aluminum target, and reduces the surface roughness of the aluminum target to the nanometer level.

[0014] At the same time, the pulsed electron impact energy field polishing process is completed in a vacuum environment, and the oxygen content in the environment is extremely low, which can effectively prevent the problem of oxidation of high-purity aluminum target during polishing.

[0015] When the energy of the pulsed electron impact energy field is too high, crater and ring mountain structures appear on the metal surface, increasing the surface roughness of the aluminum target and reducing the flatness of the material surface, affecting the subsequent sputtering and coating process; when the energy is too low, the metal surface cannot be effectively melted, and effective polishing cannot be achieved, therefore, the energy density of the pulsed electron impact energy field is limited to 1.2-2.5 J / cm 2 .

[0016] The distribution path of the pulsed electron impact energy field is limited to an equidistant Archimedean spiral, and through the cooperation between the spacing between the spirals and the action range diameter of the energy field, the full coverage and uniformity of the pulsed electron impact energy field polishing are realized.

[0017] Further, in S1, the vacuum degree is < 6.67*10 -3 pa.

[0018] Further, in S1, the pulse width of the pulsed electron impact energy field is 100-200 ns.

[0019] Further, in S1, the movement of the pulsed electron impact energy field is realized by the movement of the pulsed electron energy generating device.

[0020] Further, the pulsed electron impact energy field generating device is located above the aluminum target and moves at a speed of 1-4 mm / min.

[0021] Further, in S2, the cleaning liquid for the cleaning treatment is ethanol or water.

[0022] Further, in S1, the pretreatment includes sequentially arranged coarse polishing, cleaning and drying steps.

[0023] Further, the coarse polishing specifically comprises: coarse polishing the surface of the aluminum target by sandpaper with a mesh number of 400-2000. Preferably, sandpaper with a mesh number from small to large is used for coarse polishing in sequence.

[0024] Further, the cleaning specifically comprises: placing the aluminum target in the cleaning liquid for ultrasonic cleaning for 10-20 min.

[0025] Further, the drying specifically comprises: dehydration, blow-drying and vacuum drying treatment of the aluminum target.

[0026] Advantages of the present application:

[0027] The present application utilizes the pulsed electron impact energy field to polish the aluminum target, and by adjusting the distribution path, energy density, action range, pulse width and other process parameters of the pulsed electron impact energy field, the precision polishing of the target surface is realized, and the surface roughness of the aluminum target is reduced to the nanometer level, which provides support for improving the film uniformity of sputtering film.

[0028] The pulsed electron impact energy field polishing method of the present application has a short process flow and simple process operation, and improves the stability and efficiency of aluminum target polishing.

[0029] The pulsed electron beam polishing method of the present application does not require a large amount of polishing liquid chemical reagent, which is conducive to environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described below are only part of the embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0031] Figure 1 is the distribution path schematic diagram of the pulse electron impact energy field generating device of the embodiment 1 of the present application;

[0032] Figure 2 is the three-dimensional topography diagram of the polished aluminum target material obtained in the embodiment 3 of the present application;

[0033] Figure 3 is the three-dimensional topography diagram of the polished aluminum target material obtained in the comparative example 2 of the present application. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be described clearly and completely in combination with the specific embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative effort are within the protection scope of the present application.

[0035] The embodiment provides a pulse electron impact energy field nanoscale polishing method for 5N and 6N pure aluminum target material, which comprises the following steps:

[0036] S1, placing the pretreated aluminum target material in the cavity of the pulse electron impact energy field device, and then performing electron beam polishing on the aluminum target material by using the pulse electron impact energy field after vacuumizing;

[0037] The action range diameter of the pulse electron impact energy field is 100-400 μm, and the energy density is 1.2-2.5 J / cm 2 The distribution path of the pulse electron impact energy field is an equidistant Archimedes spiral, which moves from the edge of the aluminum target material to the center position of the aluminum target material. The distance between the adjacent lines in the Archimedes spiral is 80-320 μm, and the distance is smaller than the action range diameter of the pulse electron impact energy field.

[0038] S2, cleaning the polished aluminum target material.

[0039] The embodiment utilizes a pulsed electron impact energy field to polish an aluminum target, utilizes high-energy charged particles to bombard the surface of the target, generates a high-temperature temperature field on the metal surface, causes the metal surface to instantaneously melt, and the molten metal flows to fill the defects such as grooves and pores on the surface of the material. When the pulse ends, the surface metal liquid rapidly cools, thereby forming a smooth mirror surface structure, effectively reducing the roughness of the target surface; a strengthening layer can also be formed on the surface of the aluminum target to improve the surface hardness of the target and improve the microstructure of the target surface; by adjusting the process parameters such as the distribution path, energy density, action range, and pulse time of the pulsed electron impact energy field, the precision polishing of the target surface can be realized. Compared with the traditional aluminum target polishing method, the pulsed electron beam polishing process greatly improves the surface quality and stability of the aluminum target, and reduces the surface roughness of the aluminum target to the nanometer level; at the same time, the pulsed electron beam impact energy field polishing process is completed in a vacuum environment, and the oxygen content in the environment is extremely low, which can effectively prevent the oxidation of high-purity aluminum targets during the polishing process; when the energy of the energy field is too high, crater and ring mountain structures appear on the metal surface, increasing the surface roughness of the aluminum target and reducing the flatness of the material surface, affecting the subsequent sputtering and film coating process; when the energy is too low, the metal surface cannot be effectively melted, and the polishing purpose cannot be achieved, therefore, the energy density of the pulsed electron beam is limited to 1.2-2.5 J / cm 2 ; the distribution path of the pulsed electron impact energy field is limited to an Archimedes spiral, and through the cooperation between the pitch between the spirals and the two parameters of the pulsed electron impact energy field, full coverage and uniformity of the pulsed electron impact energy field polishing are realized.

[0040] As a preferred embodiment, in S1, the vacuum degree is <6.67x10 -3 pa; the pulse width of the pulsed electron impact energy field is 100-200 ns; the distribution of the pulsed electron impact energy field is realized by moving the pulsed electron impact energy field generating device, and the pulsed electron impact energy field generating device is located above the aluminum target and moves at a speed of 1-4 mm / min.

[0041] As a preferred embodiment, in S2, the cleaning liquid for the cleaning treatment is ethanol or water.

[0042] As a preferred embodiment, in S1, the pretreatment includes sequentially arranged rough polishing, cleaning, and drying steps; the rough polishing specifically comprises rough polishing the surface of the aluminum target by using sandpaper with a mesh number of 400-2000, preferably, sequentially using sandpaper with mesh numbers of 400, 800, 1000, and 2000; the cleaning specifically comprises ultrasonic cleaning the aluminum target in a water-based cleaning liquid for 10-20 min; and the drying specifically comprises dehydration, blow drying, and vacuum drying treatment of the aluminum target.

[0043] Example 1

[0044] This example relates to a method for nanoscale polishing of 5N and 6N pure aluminum target material by pulsed electron impact energy field, comprising the following steps:

[0045] (1) Roughly grinding the surface of the high-purity aluminum target material with sandpaper of 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in turn;

[0046] (2) Cleaning the target material after rough grinding using an ultrasonic cleaning machine. During ultrasonic cleaning, the cleaning agent is a water-based cleaning solvent, and the cleaning time is 20 minutes;

[0047] (3) Dehydrating, drying and vacuum drying the cleaned target material;

[0048] (4) Placing the dried target material into the vacuum chamber of the pulsed electron impact energy field device, and vacuumizing to a vacuum degree P < 6.67 x 10 -3 pa;

[0049] (5) Polishing the target material according to the process parameter setting, wherein the action range diameter of the pulsed electron impact energy field is 200 μm, the energy density of the pulsed electron impact energy field is 2.5 J / cm 2 , the pulse width of the pulsed electron impact energy field is 200 ns, and the pulsed electron impact energy field generating device moves from the edge of the aluminum target material to the center position of the aluminum target material according to an equidistant Archimedes spiral (referring to Figure 1 ) at a moving speed of 2 mm / min and a line interval of 160 μm;

[0050] (6) After polishing, opening the vacuum chamber of the pulsed electron impact energy field device, taking out the target material, and checking the surface quality;

[0051] (7) Cleaning the surface of the target material with water to obtain a smooth high-purity aluminum target material.

[0052] The polished high-purity aluminum target material obtained in Example 1 is tested for surface roughness using a MarSurf S1 surface profiler, and the surface roughness Ra is measured to be 55 nm. It can be seen that the aluminum target material surface of nanoscale can be obtained by the polishing process of this example 1.

[0053] Example 2

[0054] This example relates to a method for nanoscale polishing of 5N and 6N pure aluminum target material by pulsed electron impact energy field, comprising the following steps:

[0055] (1) Roughly grinding the surface of the high-purity aluminum target material with sandpaper of 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in turn;

[0056] (2) the target material after rough grinding is cleaned by using an ultrasonic cleaning machine, the cleaning agent is a water-based cleaning solvent, and the cleaning time is 15 min;

[0057] (3) the cleaned target material is subjected to dehydration, blow-drying and vacuum drying treatment;

[0058] (4) the dried target material is placed in a vacuum chamber of a pulsed electron impact energy field device, and vacuumized to a vacuum degree P < 6.67 x 10 -3 pa;

[0059] (5) the target material is subjected to pulsed electron impact energy field polishing according to process parameter setting, wherein the action range diameter of the pulsed electron impact energy field is 400 μm, the energy density of the pulsed electron impact energy field is 1.8 J / cm 2 , the pulse width of the pulsed electron impact energy field is 150 ns, and the pulsed electron impact energy field generating device moves from the edge of the aluminum target material to the center position of the aluminum target material at an equal interval according to an Archimedes spiral (referring to Figure 1 ), and the moving speed is 4 mm / min, and the line interval is 320 μm;

[0060] (6) after polishing, the vacuum chamber of the pulsed electron impact energy field device is opened, the target material is taken out, and the surface quality is checked;

[0061] (7) the surface of the target material is cleaned with water to obtain a smooth high-purity aluminum target material.

[0062] The polished high-purity aluminum target material obtained in Example 2 is subjected to surface roughness testing by using a MarSurf S1 surface profiler, and the surface roughness Ra is 180 nm. It can be seen that the aluminum target material surface of nanometer level can be obtained by the polishing process of this Example 2.

[0063] Example 3

[0064] This example relates to a pulsed electron impact energy field nanometer polishing method of 5N and 6N pure aluminum target material, comprising the following steps:

[0065] (1) the surface of the high-purity aluminum target material is roughened by using sandpaper with mesh numbers of 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in sequence;

[0066] (2) the target material after rough grinding is cleaned by using an ultrasonic cleaning machine, the cleaning agent is a water-based cleaning solvent, and the cleaning time is 10 min;

[0067] (3) the cleaned target material is subjected to dehydration, blow-drying and vacuum drying treatment;

[0068] (4) Put the dried target into the vacuum chamber of the pulsed electron impact energy field device, and vacuumize to a vacuum degree P < 6.67 x 10 -3 pa;

[0069] (5) Perform pulsed electron impact energy field polishing on the target according to the process parameter setting, wherein the action range diameter of the pulsed electron impact energy field is 100 μm, the energy density of the pulsed electron impact energy field is 1.2 J / cm 2 , the pulse width of the pulsed electron impact energy field is 100 ns, and the pulsed electron impact energy field generating device moves from the edge of the aluminum target to the center position of the aluminum target at an equal interval Archimedes spiral (referring to Figure 1 ) at a moving speed of 1 mm / min and a line interval of 80 μm;

[0070] (6) After polishing, open the vacuum chamber of the pulsed electron impact energy field device, take out the target, and check the surface quality;

[0071] (7) Wash the surface of the target with water to obtain a smooth high-purity aluminum target.

[0072] The polished high-purity aluminum target obtained in Example 3 is subjected to surface roughness testing using a MarSurf S1 surface profiler, and the surface roughness Ra is measured to be 30 nm. It can be seen that the aluminum target surface of nanometer level can be obtained by the polishing process of Example 3. A three-dimensional laser microscopic imaging system produced by Japan Keyence is used to test the surface of the high-purity aluminum target, and a three-dimensional topography map of the polished target is obtained, referring to Figure 2 .

[0073] Comparative Example 1

[0074] The comparative example provides a polishing method of an aluminum target, comprising the following steps:

[0075] (1) Grind the high-purity aluminum target with sandpaper with mesh numbers of 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in sequence;

[0076] (2) Use a metallographic sample grinding and polishing machine to polish the target preliminarily ground in step (1), the polishing machine rotates at a speed of 500 r / min, the polishing time is 20 min, and the selected polishing cloth is velvet polishing cloth;

[0077] (3) Wash the surface of the target with water to obtain a smooth high-purity aluminum target.

[0078] The polished high-purity aluminum target obtained in Comparative Example 1 is subjected to surface roughness testing using a MarSurf S1 surface profiler, and the surface roughness Ra is measured to be 1460 nm, which is more than 40 times the surface roughness of the high-purity aluminum target obtained in Example 3.

[0079] Comparative Example 2

[0080] This comparative example provides a polishing method for an aluminum target, comprising the following steps:

[0081] (1) The high-purity aluminum target was polished with sandpaper of 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in sequence;

[0082] (2) The target material after rough grinding is cleaned using an ultrasonic cleaning machine. During ultrasonic cleaning, the cleaning agent is a water-based cleaning solvent, and the cleaning time is 10 minutes;

[0083] (3) Dehydrating, drying and vacuum drying the cleaned target;

[0084] (4) Polishing the target material using an orbital polishing machine: Install the polishing pad on the polishing disc, place the dried target material on the polishing head of the polishing machine, open the polishing liquid valve, and after the polishing liquid is completely soaked, the polishing head and the polishing disc start to rotate to polish the target material; wherein, during the polishing process, the pressure applied to the polishing head is 2 psi, the polishing head speed is 70 rpm, the polishing disc speed is 85 rpm, the polishing time is 5 min, and the polishing liquid flow rate is 150 mL / min; the polishing liquid used is composed of: 1 wt% nano α-Al2O3 particles, 0.5 wt% lactic acid, 1 wt% H2O2 oxidant and water, and the pH is adjusted to 3.5;

[0085] (5) After polishing is completed, the target material is taken out and the surface of the target material is cleaned with water to obtain a high-purity aluminum target material with a smooth surface.

[0086] The surface roughness of the polished high-purity aluminum target obtained in Comparative Example 2 was tested using a MarSurf S1 surface profiler, and the surface roughness Ra was measured to be 260 nm, which was significantly greater than the surface roughness of the high-purity aluminum target obtained in Example 2. The surface of the high-purity aluminum target was tested using a three-dimensional laser microscopy system produced by Keyence Japan to obtain a three-dimensional morphology image after polishing. Figure 3 ,and Figure 2 In comparison, it can be seen that the roughness of the aluminum target obtained in Comparative Example 2 is significantly higher than that of the aluminum target obtained in Example 3, and the comparative example process requires a large amount of polishing agent chemical reagents, which seriously pollutes the environment.

[0087] In summary, the present application utilizes the pulse electron impact energy field to polish the aluminum target material, and through regulating and controlling the distribution path, energy density, action range, pulse width and other process parameters of the pulse electron impact energy field, the precise polishing of the target material surface is realized, the surface roughness of the aluminum target material is reduced to the nanometer level, and the film uniformity of sputtering film is improved; the pulse electron impact energy field polishing method has short process flow and simple process operation, and the stability and efficiency of the aluminum target material polishing are improved; the pulse electron beam polishing method does not need a large number of polishing liquid chemicals, and is conducive to environmental protection.

[0088] The present application has been described in detail with reference to specific embodiments and exemplary examples, but these descriptions are not to be construed as limiting the present application. Those skilled in the art understand that various equivalent substitutions, modifications or improvements can be made to the technical solutions and embodiments of the present application without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The scope of protection of the present application is subject to the appended claims.

Claims

1. A method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field, characterized in that: The steps include: S1. Placing the pretreated aluminum target in a pulsed electron impact energy field device cavity, evacuating the cavity, and performing nano-level polishing on the surface of the aluminum target using the generated pulsed electron impact energy field; The pulse electron impact energy field has a diameter of 100-400 μm and an energy density of 1.2-2.5 J / cm 2 ; The distribution path of the pulse electron impact energy field is an equally spaced Archimedean spiral, moving from the edge of the aluminum target to the center of the aluminum target; The spacing between adjacent lines in the Archimedean spiral is 80-320 μm, and the spacing is smaller than the diameter of the range of action of the pulse electron impact energy field; S2. Cleaning the polished aluminum target.

2. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 1, characterized in that: In S1, the vacuum is evacuated to a vacuum degree of <6.67×10 -3 pa.

3. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 1, characterized in that: In S1, the pulse width of the pulse electron impact energy field is 100-200 ns.

4. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 1, characterized in that: In S1, the movement of the pulse electron impact energy field is achieved by moving the pulse electron energy generating device.

5. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 4, characterized in that: The pulse electron energy generating device is located above the aluminum target and moves at a speed of 1-4 mm / min.

6. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 1, characterized in that: In S2, the cleaning liquid used in the cleaning process is ethanol or water.

7. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 1, characterized in that: In S1, the pretreatment includes sequentially arranged steps of rough polishing, cleaning and drying.

8. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 7, characterized in that: The rough polishing specifically includes: rough polishing the surface of the aluminum target material by using sandpaper with a mesh number of 400-2000.

9. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 7, wherein: The cleaning specifically includes placing the aluminum target in a cleaning solution and ultrasonically cleaning the target for 10-20 minutes.

10. The method for nano-level polishing of 5N and 6N pure aluminum targets using a pulsed electron impact energy field as claimed in claim 7, characterized in that: The drying specifically includes: dehydrating, blowing and vacuum drying the aluminum target.

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