Recovery method of aluminum target material containing indium solder

Abstract

The invention provides a recovery method of an aluminum target material containing indium solder. The recovery method comprises the following steps: sequentially carrying out freezing treatment and sand blasting treatment on an aluminum target material containing indium solder, and recovering to obtain an aluminum matrix; wherein the sand blasting treatment medium comprises the following components in percentage by mass: 55%-65% of dry ice, 25%-35% of aluminum oxide powder and 10%-15% of boron nitride powder. According to the recovery method, firstly, the surface of the indium solder is embrittled through freezing treatment, a compact crack grid is formed, and the interface bonding strength of the aluminum matrix and the indium solder is reduced; and meanwhile, the mixture of the dry ice, the aluminum oxide powder and the boron nitride powder with the specific mass fraction is adopted as a medium for sand blasting treatment, the indium solder can be effectively stripped from the aluminum matrix, and damage to the aluminum matrix is small.

Description

Technical Field

[0001] This application relates to the technical field of target recycling and treatment, and particularly to a method for recycling an indium-containing solder aluminum target. Background Art

[0002] Sputtering process is a thin film deposition technology. By placing the target in a high vacuum environment and using ion bombardment on the target surface, the target atoms or molecules are sputtered out and deposited on the substrate to form a thin film. Indium is a metal with a low melting point (157 °C), and has good electrical conductivity and thermal conductivity, and is commonly used in electronic packaging and low-temperature solders.

[0003] When the sputtering target reaches the end of its service life, it needs to be peeled off from the backplane; however, the indium solder remaining on the welding surface is difficult to be completely peeled off, thus limiting the recycling and reuse of the target. Therefore, it is necessary to effectively remove the indium solder on the target surface to improve the recovery rate and purity of the target.

[0004] Traditional technologies mainly use methods such as melting method, chemical etching method and laser peeling method to remove the indium solder deposited on the surface of the aluminum target, but the indium residue is still relatively high and difficult to meet the requirements. Summary of the Invention

[0005] Based on this, this application provides a method for recycling an indium-containing solder aluminum target, which can efficiently recycle the aluminum matrix from the indium-containing solder aluminum target.

[0006] According to the first aspect of the embodiments of this application, a method for recycling an indium-containing solder aluminum target is provided, including the following steps:

[0007] The indium-containing solder aluminum target is sequentially subjected to freezing treatment and sandblasting treatment to recover the aluminum matrix;

[0008] Wherein, by mass fraction, the medium for the sandblasting treatment includes 55% - 65% dry ice, 25% - 35% alumina powder, and 10% - 15% boron nitride powder.

[0009] In some embodiments, the average particle size of the dry ice is 150 μm - 200 μm; and / or,

[0010] The average particle size of the alumina powder is 40 μm - 50 μm; and / or,

[0011] The average particle size of the boron nitride powder is 20 μm - 25 μm.

[0012] In some embodiments, the medium for the sandblasting treatment includes 58% - 63% dry ice, 25% - 30% alumina powder, and 12% - 15% boron nitride powder.

[0013] In some of these embodiments, the final temperature of the freezing treatment is -190°C to -200°C;

[0014] Optionally, the freezing treatment includes a first freezing treatment, a second freezing treatment, and a third freezing treatment performed in sequence; the temperature of the first freezing treatment is -75°C to -85°C; the temperature of the second freezing treatment is -140°C to -160°C; the temperature of the third freezing treatment is -190°C to -200°C.

[0015] In some of these embodiments, the steps of the first freezing treatment include: cooling at a rate of 10°C / min to 15°C / min to the final temperature of the first freezing treatment, and holding for 3 min to 5 min; and / or,

[0016] The steps of the second freezing treatment include: cooling from the final temperature of the first freezing treatment to the final temperature of the second freezing treatment at a rate of 15°C / min to 20°C / min, and holding for 3 min to 5 min; and / or,

[0017] The steps of the third freezing treatment include: cooling from the final temperature of the second freezing treatment to the final temperature of the third freezing treatment at a rate of 20°C / min to 25°C / min, and holding for 3 min to 5 min; and / or,

[0018] The total time of the freezing treatment is less than or equal to 30 min.

[0019] In some of these embodiments, in the sandblasting treatment, the pressure of the sandblasting is 1.2 MPa to 1.8 MPa; and / or,

[0020] In the sandblasting treatment, the distance between the nozzle of the spray gun used and the indium-containing solder aluminum target is 10 cm to 15 cm; and / or,

[0021] In the sandblasting treatment, the angle formed by the spray gun used and the indium-containing solder aluminum target is 65° to 75°.

[0022] In some of these embodiments, before the freezing treatment, the following steps are further included: performing plasma cleaning on the indium-containing solder aluminum target;

[0023] Optionally, the gases used for the plasma cleaning include argon and hydrogen;

[0024] Optionally, the power of the plasma cleaning is 380 W to 420 W, and the time is 8 min to 12 min.

[0025] In some of these embodiments, after the sandblasting treatment, the following steps are further included: performing electrolytic polishing treatment on the indium-containing solder aluminum target;

[0026] Optionally, the voltage of the electrolytic polishing treatment is 10V - 12V;

[0027] Optionally, the electrolytic solution for the electrolytic polishing treatment includes H3PO4 solution.

[0028] In some embodiments, after the electrolytic polishing treatment, the following steps are further included: performing vacuum annealing treatment on the indium-containing solder aluminum target;

[0029] Optionally, the temperature of the vacuum annealing treatment is 270°C - 290°C, and the time is 30min - 45min;

[0030] Optionally, the vacuum degree of the vacuum annealing treatment is less than or equal to 5×10 -4 Pa.

[0031] In some embodiments, after the electrolytic polishing treatment, the following steps are further included: performing hydrogen plasma reduction treatment on the indium-containing solder aluminum target;

[0032] Optionally, the temperature of the hydrogen plasma reduction treatment is 310°C - 330°C, and the time is 15min - 25min.

[0033] Compared with the traditional technology, the present application has the following beneficial effects:

[0034] In the above recycling method, first, the surface of the indium solder is embrittled and a dense crack grid is formed through freezing treatment, reducing the interfacial bonding strength between the aluminum matrix and the indium solder; meanwhile, a mixture of dry ice, alumina powder, and boron nitride powder with a specific mass fraction is used as the medium for sandblasting treatment. Among them, during the process of dry ice directly changing from solid state to gaseous state, there is a sharp expansion in volume, which can expand the cracks on the surface of the indium solder, thereby improving the separation efficiency between the aluminum matrix and the indium solder; alumina powder has a high hardness, which can cut and peel off the indium solder attached to the surface of the aluminum matrix; boron nitride powder has a high thermal conductivity, which can inhibit the temperature rise of the aluminum matrix, thereby reducing the change in the grain size of the aluminum matrix and reducing the reaction energy consumption at the same time; thus, after freezing treatment, combined with sandblasting treatment with a specific medium, the indium solder can be effectively peeled off from the aluminum matrix with less damage to the aluminum matrix. Detailed Embodiments

[0035] To make the above objects, features, and advantages of the present application more obvious and understandable, the specific embodiments of the present application are described in detail. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in this application can be obtained through the market or can be prepared by existing methods.

[0037] In this application, the terms "a plurality of", "multiple", "multiple times", "plurality of elements", etc., unless otherwise specified, mean greater than or equal to 2 in number. For example, "one or more" means one or greater than or equal to two.

[0038] In this application, terms such as "further", "even further", "particularly", etc. are used for descriptive purposes and represent differences in content, but should not be construed as limiting the scope of protection of this application.

[0039] In this application, "optionally", "optional", "option", mean that it can be present or absent, that is, it refers to any one of the two alternative schemes of "present" or "absent". If "optional" appears multiple times in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction relationship, each "optional" is independent of each other.

[0040] In this application, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, and also includes an open technical solution containing the listed features.

[0041] In this application, regarding numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical values are considered continuous within the above numerical intervals, and include the two numerical endpoints of this numerical range (i.e., the minimum value and the maximum value), as well as each numerical value between these two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to integers within the numerical interval, it includes the two endpoint integers of this numerical range, as well as each integer between the two endpoints. In this article, it is equivalent to directly listing each integer. For example, t is an integer selected from 1 - 10, which means t is any integer selected from the integer group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0042] The temperature parameters in this application, unless otherwise specified, allow both constant temperature treatment and variation within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, ±1°C are allowed.

[0043] Some embodiments of this application provide a method for recycling an indium-containing solder aluminum target, comprising the following steps:

[0044] The indium-containing solder aluminum target is successively subjected to freezing treatment and sandblasting treatment to recover the aluminum matrix;

[0045] Among them, by mass fraction, the medium for sandblasting treatment includes 55% - 65% dry ice, 25% - 35% alumina powder, and 10% - 15% boron nitride powder.

[0046] In the above recycling method of this application, first, the surface of the indium solder layer is embrittled and a dense crack grid is formed through freezing treatment, reducing the interfacial bonding strength between the aluminum matrix and the indium solder; at the same time, a mixture of dry ice, alumina, and boron nitride with specific mass fractions is used as the medium for sandblasting treatment, which can effectively peel the indium solder from the aluminum matrix with less damage to the aluminum matrix.

[0047] Among them, during the process of dry ice directly changing from solid to gas at room temperature, there is a sharp expansion in volume (the volume expansion coefficient of dry ice is 1:700), which can expand the cracks on the surface of the indium solder layer, thereby improving the separation efficiency between the aluminum matrix and the indium solder; alumina has a high hardness (HV 2000), which can cut and peel the indium solder attached to the surface of the aluminum matrix; boron nitride has a high thermal conductivity (400 W / m·K), which can inhibit the temperature rise of the aluminum matrix, thereby reducing the change in the grain size of the aluminum matrix and reducing the reaction energy consumption at the same time.

[0048] In some of these embodiments, the sandblasting treatment is carried out at room temperature; for example, the temperature of the sandblasting treatment can be 18°C - 35°C.

[0049] In some of these embodiments, the mass content of the indium solder in the indium-containing solder aluminum target is 2% - 5%.

[0050] As an example, the mass fraction of dry ice in the medium for sandblasting can be 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, or any value within the range formed by any two of the above point values. The mass fraction of alumina powder can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, or any value within the range formed by any two of the above point values. The mass fraction of boron nitride powder can be 10%, 11%, 12%, 13%, 14%, 15%, or any value within the range formed by any two of the above point values.

[0051] Furthermore, the medium for sandblasting includes 58% - 63% dry ice, 25% - 30% alumina powder, and 12% - 15% boron nitride powder.

[0052] In some embodiments, the average particle size of dry ice is 150μm - 200μm. As an example, the average particle size of dry ice can be 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, or any value within the range formed by any two of the above point values.

[0053] In some embodiments, the average particle size of alumina powder is 40μm - 50μm. As an example, the average particle size of alumina powder can be 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, or any value within the range formed by any two of the above point values.

[0054] In some embodiments, the average particle size of boron nitride powder is. As an example, the average particle size of boron nitride powder can be 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, or any value within the range formed by any two of the above point values.

[0055] It can be understood that controlling the average particle sizes of dry ice, alumina powder, and boron nitride powder within the above ranges can effectively cut the indium solder on the surface of the aluminum matrix without significantly increasing the surface roughness of the aluminum matrix, thereby reducing the workload of subsequent grinding and polishing treatments.

[0056] In some embodiments, the final temperature of the freezing treatment is -200°C to -190°C.

[0057] In some embodiments, the freezing treatment includes a first freezing treatment, a second freezing treatment, and a third freezing treatment performed in sequence;

[0058] The temperature of the first freezing treatment is -75°C to -85°C; the temperature of the second freezing treatment is -140°C to -160°C; the temperature of the third freezing treatment is -190°C to -200°C.

[0059] It can be understood that in some examples, the temperature of the third freezing treatment is the final temperature of the freezing treatment.

[0060] As an example, the temperature of the first freezing treatment can be -75°C, -76°C, -77°C, -78°C, -79°C, -80°C, -81°C, -82°C, -83°C, -84°C, -85°C, or any value within the range formed by any two of the above point values. The temperature of the second freezing treatment can be -140°C, -141°C, -142°C, -143°C, -144°C, -145°C, -146°C, -147°C, -148°C, -149°C, -150°C, -151°C, -152°C, -153°C, -154°C, -155°C, -156°C, -157°C, -158°C, -159°C, -160°C, or any value within the range formed by any two of the above point values. The temperature of the third freezing treatment can be -190°C, -191°C, -192°C, -193°C, -194°C, -195°C, -196°C, -197°C, -198°C, -199°C, -200°C, or any value within the range formed by any two of the above point values.

[0061] In some examples, the temperature of the first freezing treatment is -80°C, the temperature of the second freezing treatment is -150°C, and the temperature of the third freezing treatment is -196°C.

[0062] In some of these embodiments, the steps of the first freezing treatment include: cooling to the final temperature of the first freezing treatment at a rate of 10°C / min to 15°C / min and holding for 3 min to 5 min.

[0063] As an example, the cooling rate of the first freezing treatment can be 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min, 15°C / min, or any value within the range formed by any two of the above point values. The holding time of the first freezing treatment can be 3 min, 4 min, 5 min, or any value within the range formed by any two of the above point values.

[0064] In some of these embodiments, the steps of the second freezing treatment include: cooling from the final temperature of the first freezing treatment to the final temperature of the second freezing treatment at a rate of 15°C / min to 20°C / min and holding for 3 min to 5 min.

[0065] As an example, the cooling rate of the second freezing treatment can be 15°C / min, 16°C / min, 17°C / min, 18°C / min, 19°C / min, 20°C / min, or any value within the range formed by any two of the above point values. The heat preservation time of the second freezing treatment can be 3 min, 4 min, 5 min, or any value within the range formed by any two of the above point values.

[0066] In some embodiments, the steps of the third freezing treatment include: cooling from the final temperature of the second freezing treatment to the final temperature of the third freezing treatment at a rate of 20°C / min to 25°C / min, and keeping warm for 3 min to 5 min.

[0067] The cooling rate of the third freezing treatment can be 20°C / min, 21°C / min, 22°C / min, 23°C / min, 24°C / min, 25°C / min, or any value within the range formed by any two of the above point values. The heat preservation time of the third freezing treatment can be 3 min, 4 min, 5 min, or any value within the range formed by any two of the above point values.

[0068] In some embodiments, the total time of the freezing treatment is less than or equal to 30 min. As an example, the total time of the freezing treatment can be 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, or any value within the range formed by any two of the above point values.

[0069] Furthermore, the total time of the freezing treatment can be 1 min to 30 min.

[0070] It can be understood that the total time of the freezing treatment refers to the total duration including heating and heat preservation, and effective freezing of the aluminum target can be achieved within the above range.

[0071] The present application performs the freezing treatment by means of staged cooling, which can form an orthogonal crack grid on the surface of the indium solder layer, and the density of the cracks exceeds 250 cracks / mm 2, which is three times that of the traditional liquid nitrogen freezing method, can greatly reduce the interfacial bonding strength between the aluminum substrate and the indium solder layer; at the same time, by maintaining a certain period of time at the end temperature after cooling in each stage, the internal stress of the aluminum substrate can be effectively eliminated, making the internal residual stress of the aluminum substrate less than 40 MPa. In this way, through the freezing treatment, the indium solder layer can be more easily peeled off from the surface of the aluminum substrate in this application.

[0072] It can be understood that by controlling the cooling rates of the first freezing treatment, the second freezing treatment, and the third freezing treatment within the above specific ranges, the internal stress distribution of the aluminum substrate can be made more uniform, thereby reducing the difficulty of peeling between the aluminum substrate and the indium solder layer.

[0073] In some of these embodiments, during the sandblasting treatment, the pressure of the sandblasting is 1.2 MPa to 1.8 MPa. As an example, the pressure of the sandblasting can be 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, or any value within the range formed by any two of the above point values.

[0074] In some of these embodiments, during the sandblasting treatment, the distance between the nozzle of the spray gun used and the indium solder-containing aluminum target is 10 cm to 15 cm. As an example, the distance between the nozzle of the spray gun and the indium solder-containing aluminum target can be 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, or any value within the range formed by any two of the above point values.

[0075] In some of these embodiments, during the sandblasting treatment, the included angle formed by the spray gun used and the indium solder-containing aluminum target is 65° to 75°. As an example, the included angle formed by the spray gun and the indium solder-containing aluminum target can be 65°, 66°, 67°, 68°, 69°, 70°, 71°, 72°, 73°, 74°, 75°, or any value within the range formed by any two of the above point values.

[0076] In some of these embodiments, before the freezing treatment, the following steps are further included: performing plasma cleaning on the indium solder-containing aluminum target.

[0077] In some examples, the gases used for plasma cleaning include argon and hydrogen. Further, the volume ratio of argon to hydrogen is 9:1.

[0078] In some examples, the power of the plasma cleaning is 380 W to 420 W, and the time is 8 min to 12 min.

[0079] As an example, the power of plasma cleaning can be 380W, 390W, 400W, 410W, 420W, or any value within the range formed by any two of the above point values. The time of plasma cleaning can be 8min, 9min, 10min, 11min, 12min, or any value within the range formed by any two of the above point values.

[0080] Surface pretreatment of the aluminum target of indium solder by plasma cleaning can effectively remove oxides and organic pollutants on the surface of the aluminum target.

[0081] In some of these embodiments, after the sandblasting treatment, the following steps are further included: electrolytic polishing treatment of the aluminum target containing indium solder;

[0082] In some examples, the voltage of the electrolytic polishing treatment is 10V - 12V. As an example, the voltage of the electrolytic polishing treatment can be 10V, 11V, 12V, or any value within the range formed by any two of the above point values.

[0083] In some examples, the electrolytic solution for the electrolytic polishing treatment includes H3PO4 solution.

[0084] It can be understood that through the electrolytic polishing treatment, the oxide layer on the surface of the aluminum substrate can be removed, and at the same time, the surface of the aluminum substrate can be polished smoothly to reduce its roughness.

[0085] In some of these embodiments, after the electrolytic polishing treatment, the following steps are further included: vacuum annealing treatment of the aluminum target containing indium solder.

[0086] In some of these embodiments, the temperature of the vacuum annealing treatment is 270°C - 290°C, and the time is 30min - 45min. As an example, the temperature of the vacuum annealing treatment can be 270°C, 271°C, 272°C, 273°C, 274°C, 275°C, 276°C, 277°C, 278°C, 279°C, 280°C, 281°C, 282°C, 283°C, 284°C, 285°C, 286°C, 287°C, 288°C, 289°C, 290°C, or any value within the range formed by any two of the above point values. The time of the vacuum annealing treatment can be 30min, 31min, 32min, 33min, 34min, 35min, 36min, 37min, 38min, 39min, 40min, 41min, 42min, 43min, 44min, 45min, or any value within the range formed by any two of the above point values.

[0087] It can be understood that by performing vacuum annealing treatment on the cold-worked aluminum target, the grain size in the aluminum substrate can be restored, and the deviation from the original size is less than 1%.

[0088] In some of these embodiments, the degree of vacuum in the vacuum annealing treatment is less than or equal to 5×10 -4 Pa.

[0089] In some of these embodiments, after the electrolytic polishing treatment, the following steps are further included: performing a hydrogen plasma reduction treatment on the indium-containing solder aluminum target.

[0090] In some of these embodiments, the temperature of the hydrogen plasma reduction treatment is 310°C to 330°C, and the time is 15 min to 25 min.

[0091] As an example, the temperature of the hydrogen plasma reduction treatment can be 310°C, 311°C, 312°C, 313°C, 314°C, 315°C, 316°C, 317°C, 318°C, 319°C, 320°C, 321°C, 322°C, 323°C, 324°C, 325°C, 326°C, 327°C, 328°C, 329°C, 330°C, or any value within the range formed by any two of the above point values. The time of the hydrogen plasma reduction treatment can be 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, or any value within the range formed by any two of the above point values.

[0092] It can be understood that the hydrogen plasma reduction treatment can effectively remove the oxides on the surface of the aluminum matrix, thereby further reducing the oxygen content on the surface of the aluminum matrix.

[0093] In some of these embodiments, after the electrolytic polishing treatment, a vacuum annealing treatment and a hydrogen plasma reduction treatment are sequentially performed.

[0094] It can be understood that precise control of the surface microstructure of the aluminum matrix can be achieved through the electrolytic polishing treatment, the vacuum annealing treatment, and the hydrogen plasma reduction treatment.

[0095] In the method for recycling the indium-containing solder aluminum target of the present application, each step acts synergistically, and finally the surface damage depth of the recovered aluminum matrix is ≤0.3 μm, the oxygen content is ≤0.08 at%, the aluminum grain size recovery rate is ≥99%, and the indium residue content is ≤0.003 wt%. At the same time, when using the method of the present application to recycle the aluminum matrix, the treatment time only needs 20 min to 30 min, and the unit energy consumption only needs 6.0 kWh / Kg to 7.5 kWh / Kg, which is significantly faster and more efficient compared with the traditional method.

[0096] The present application will be further described below in conjunction with specific embodiments and comparative examples, but it should not be construed as a limitation on the protection scope of the present application. The raw materials involved in the following specific embodiments, unless otherwise specified, can all be obtained commercially. The instruments used, unless otherwise specified, can all be obtained commercially. The processes involved, unless otherwise specified, are all conventional selections for those skilled in the art.

[0097] Example 1

[0098] (1)Surface activation treatment: The aluminum target containing indium solder is subjected to plasma cleaning using a mixed gas of argon and hydrogen (the volume ratio of argon to hydrogen is 9:1); the power of plasma cleaning is 400 W and the time is 10 min. Among them, the content of indium solder in the aluminum target is about 2.5 wt%.

[0099] (2)Gradient freezing treatment: Cool from 25 °C to -80 °C at a rate of 13 °C / min and hold for 3 min; cool from -80 °C to -150 °C at a rate of 17 °C / min and hold for 3 min; cool from -150 °C to -196 °C at a rate of 20 °C / min and hold for 5 min; the total time of gradient freezing treatment is 25 min.

[0100] (3)Sandblasting treatment: At room temperature, by mass fraction, 60% of dry ice with an average particle size of 175 μm, 30% of alumina powder with an average particle size of 45 μm, and 10% of boron nitride powder with an average particle size of 23 μm are mixed as the sandblasting medium. The sandblasting pressure is 1.8 MPa, the distance between the nozzle of the spray gun and the surface of the aluminum target is 12 cm, and the angle between the spray gun and the surface of the aluminum target is 70°.

[0101] (4)Electropolishing treatment: Using H3PO4 solution as the electrolyte, treat at a voltage of 10 V for 5 min.

[0102] (5)Vacuum annealing treatment: Treat at a vacuum degree of 4×10 -4 Pa and a temperature of 280 °C for 35 min.

[0103] Based on the treatments in the above steps (1) to (5), an aluminum matrix is recovered.

[0104] Example 2

[0105] It is basically the same as Example 1, except that the ratio of the sandblasting medium in step (3) is different. Specifically, by mass fraction, the sandblasting medium in Example 2 includes 57% dry ice, 28% alumina powder, and 15% boron nitride powder.

[0106] Example 3

[0107] Basically the same as Example 1, except that after step (5), it further includes a step of hydrogen plasma reduction treatment. Specifically as follows:

[0108] (6) Carry out hydrogen plasma reduction treatment on the indium-containing solder aluminum target at a temperature of 320 °C for 20 min.

[0109] Example 4

[0110] Basically the same as Example 1, except that the ratio of the medium for sandblasting treatment in step (3) is different. Specifically, by mass fraction, the sandblasting medium in Example 4 includes 63% dry ice, 25% alumina powder, and 12% boron nitride powder.

[0111] Example 5

[0112] Basically the same as Example 1, except that the freezing treatment in step (2) is a two-stage freezing treatment. Specifically as follows:

[0113] (2) Gradient freezing treatment: Cool down from 25 °C to -80 °C at a rate of 15 °C / min, and then cool down from -80 °C to -196 °C at a rate of 25 °C / min, and hold for 5 min.

[0114] Example 6

[0115] Basically the same as Example 1, except that the freezing treatment in step (2) is to directly cool down to -196 °C and hold for 50 min.

[0116] Comparative Example 1

[0117] Basically the same as Example 1, except that steps (2) and (3) are different. Specifically as follows:

[0118] (2) Freezing treatment: Directly cool down to -196 °C and hold for 50 min.

[0119] (3) Sandblasting treatment: At room temperature, use 175 μm dry ice as the sandblasting medium, the sandblasting pressure is 1.8 MPa, the distance between the nozzle of the spray gun and the surface of the aluminum target is 12 cm, and the angle between the spray gun and the surface of the aluminum target is 70°.

[0120] Comparative Example 2

[0121] (1) Use a diamond tool to perform turning on the indium-containing solder aluminum target: The turning depth is the average thickness of the solder layer, and the turning speed is 1.5 m / s; after turning, use a water-based emulsion for cooling.

[0122] (2) Pickling treatment: Use a 7 wt% HNO3 solution and carry out pickling by ultrasonic (frequency 40 Hz) for 60 min at room temperature.

[0123] After the treatment in the above steps (1)-(2), an aluminum matrix is recovered.

[0124] Comparative Example 3

[0125] It is basically the same as Example 1, except that the ratio of the media for sandblasting treatment in step (3) is different. Specifically, by mass fraction, the sandblasting medium in Comparative Example 3 includes 60% dry ice, 35% alumina powder, and 5% boron nitride powder.

[0126] The properties of the aluminum matrices recovered in the above examples and comparative examples are tested respectively. Among them, the indium solder residue amount is detected by inductively coupled plasma mass spectrometry (ICP-MS); the damage depth of the aluminum matrix is detected by scanning electron microscopy (SEM); the grain size recovery rate is calculated by electron backscatter diffraction (EBSD); the residue target recovery rate is calculated according to the mass of the residue target; the oxygen content on the surface of the aluminum matrix is tested by X-ray photoelectron spectroscopy (XPS); the surface roughness is tested by atomic force microscopy (AFM); the test results are shown in Table 1.

[0127] Table 1

[0128]

[0129] As can be seen from the above table, in Comparative Example 1, the combination of one-step cooling and freezing treatment and sandblasting treatment with pure dry ice is adopted, and the indium residue amount on the surface of the finally recovered aluminum matrix is 0.28 wt%, and the damage depth is 5.36 μm, and its performance is much lower than that of the aluminum matrices recovered in Examples 1-5 of the present application.

[0130] In Comparative Example 2, the traditional mechanical peeling method is adopted for recovery, and the final aluminum recovery rate is only 50%, and the oxygen content on the surface of the aluminum matrix is 2.5 at%, which does not meet the standards of the Semiconductor Equipment and Materials International (SEMI).

[0131] In Comparative Example 3, the mass content of boron nitride powder is only 5%, and the damage depth on the surface of the finally recovered aluminum matrix reaches 1.85 μm, the surface roughness is 0.23 μm, and the grain size recovery rate is only 90.5%.

[0132] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0133] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A method for recovering an aluminum target material containing indium solder, characterized in that: The steps include: The aluminum target material containing indium solder is subjected to freezing treatment and sandblasting treatment in sequence, and an aluminum matrix is ​​recovered; Wherein, by mass fraction, the medium for sandblasting includes 55% to 65% dry ice, 25% to 35% alumina powder and 10% to 15% boron nitride powder.

2. The method for recovering an aluminum target material containing indium solder according to claim 1, characterized in that: The average particle size of the dry ice is 150 μm to 200 μm; and / or, The average particle size of the alumina powder is 40 μm to 50 μm; and / or, The average particle size of the boron nitride powder is 20 μm to 25 μm.

3. The method for recovering an aluminum target material containing indium solder according to claim 1, characterized in that: The medium for sandblasting includes 58% to 63% dry ice, 25% to 30% alumina powder and 12% to 15% boron nitride powder.

4. The method for recovering an aluminum target material containing indium solder according to any one of claims 1 to 3, characterized in that: The final temperature of the freezing treatment is -190°C to -200°C; Optionally, the freezing treatment includes a first freezing treatment, a second freezing treatment and a third freezing treatment performed in sequence; the temperature of the first freezing treatment is -75℃~-85℃; the temperature of the second freezing treatment is -140℃~-160℃; the temperature of the third freezing treatment is -190℃~-200℃.

5. The method for recovering an aluminum target material containing indium solder according to claim 4, characterized in that: The first freezing treatment step comprises: cooling at a rate of 10°C / min to 15°C / min to the final temperature of the first freezing treatment, and keeping the temperature for 3min to 5min; and / or, The second freezing treatment step comprises: cooling from the final temperature of the first freezing treatment to the final temperature of the second freezing treatment at a rate of 15°C / min to 20°C / min, and keeping the temperature for 3min to 5min; and / or, The step of the third freezing treatment comprises: cooling from the final temperature of the second freezing treatment to the final temperature of the third freezing treatment at a rate of 20°C / min to 25°C / min, and keeping the temperature for 3min to 5min; and / or, The total time of the freezing treatment is less than or equal to 30 minutes.

6. The method for recovering an aluminum target material containing indium solder according to any one of claims 1 to 3 and 5, characterized in that: In the sandblasting process, the sandblasting pressure is 1.2MPa~1.8MPa; and / or, In the sandblasting process, the distance between the nozzle of the spray gun used and the aluminum target material containing indium solder is 10 cm to 15 cm; and / or, In the sandblasting process, the angle formed by the spray gun used and the aluminum target material containing indium solder is 65° to 75°.

7. The method for recovering an aluminum target material containing indium solder according to any one of claims 1 to 3 and 5, characterized in that: Before the freezing treatment, the method further includes the following steps: plasma cleaning the aluminum target material containing the indium solder; Optionally, the gas used for plasma cleaning includes argon and hydrogen; Optionally, the power of the plasma cleaning is 380W~420W, and the time is 8min~12min.

8. The method for recovering an aluminum target material containing indium solder according to any one of claims 1 to 3 and 5, characterized in that: After the sandblasting treatment, the method further comprises the following steps: electrolytic polishing the aluminum target material containing the indium solder; Optionally, the voltage of the electrolytic polishing treatment is 10V~12V; Optionally, the electrolytic solution of the electrolytic polishing treatment includes a H3PO4 solution.

9. The method for recovering an aluminum target material containing indium solder according to claim 8, characterized in that: After the electrolytic polishing treatment, the method further includes the following steps: vacuum annealing the aluminum target material containing the indium solder; Optionally, the vacuum annealing treatment is performed at a temperature of 270° C. to 290° C. and for a time of 30 min to 45 min; Optionally, the vacuum degree of the vacuum annealing treatment is less than or equal to 5×10 -4 Pa.

10. The method for recovering an aluminum target material containing indium solder according to claim 8, characterized in that: After the electrolytic polishing treatment, the method further includes the following steps: performing a hydrogen plasma reduction treatment on the aluminum target material containing the indium solder; Optionally, the temperature of the hydrogen plasma reduction treatment is 310° C. to 330° C., and the time is 15 min to 25 min.

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