Method for producing high-purity aluminum-silicon-copper target blanks

Abstract

The application belongs to the technical field of metal processing, and discloses a preparation method of high-purity aluminum-silicon-copper target blank, which comprises the following steps: sequentially heating and pretreating, upsetting forging, multi-direction rolling, heat treating high-purity aluminum-silicon-copper cast ingot, and obtaining the high-purity aluminum-silicon-copper target blank. The cast ingot obtained through the above method has uniform internal structure, uniform grain size distribution and no cracks. Moreover, the process provided by the application is simple, short in completion time, low in cost, and beneficial to industrialized popularization and application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal processing, and particularly relates to a preparation method of high-purity aluminum-silicon-copper target blank. BACKGROUND

[0002] In the production process of semiconductor chips and TFT-LCDs, the most critical step is physical vapor deposition. One of the most important consumables of the magnetron sputtering equipment commonly used in physical vapor deposition is metal target material. The largest amount of metal target material is aluminum and its alloy target material. The purity of the main metal of the target material, the size and uniformity of the crystal grains will affect the sputtering quality. In the process of preparing aluminum-silicon-copper alloy, due to the large particles of raw materials such as silicon and copper, which are easy to deposit at the bottom of the furnace, the melting time is long and the composition uniformity is difficult to control, the aluminum-silicon-copper alloy ingot often appears segregation, uneven grain, crack and other phenomena. SUMMARY

[0003] In view of the problems existing in the prior art, the purpose of the present application is to provide a preparation method of high-purity aluminum-silicon-copper target blank.

[0004] The present application provides the following specific technical solutions.

[0005] A preparation method of high-purity aluminum-silicon-copper target blank, comprising the following steps: sequentially heating pretreatment, upsetting forging, multi-directional rolling, heat treatment of high-purity aluminum-silicon-copper ingot, to obtain high-purity aluminum-silicon-copper target blank.

[0006] In a further preferred embodiment, the temperature of the heating pretreatment is 180-250 DEG C, and the time is 2-3 h.

[0007] In a further preferred embodiment, the upsetting forging is performed for more than or equal to 3 times, and heating pretreatment is performed before each upsetting forging.

[0008] In a further preferred embodiment, after the upsetting forging, the total deformation of the high-purity aluminum-silicon-copper ingot is more than or equal to 80%.

[0009] In a further preferred embodiment, the cooling mode of the upsetting forging is ice water cooling.

[0010] In a further preferred embodiment, the temperature of the multi-directional rolling is room temperature.

[0011] In a further preferred embodiment, the multi-directional rolling is performed for more than or equal to 3 times, and the single pass amount of depression is more than or equal to 1 mm.

[0012] In a further preferred embodiment, the total deformation of the high-purity aluminum-silicon-copper ingot in the multi-directional rolling is 5-10%.

[0013] In a further preferred embodiment, the cooling mode between the rolling passes is ice water cooling.

[0014] In a further preferred embodiment, the temperature of the heat treatment is 450-500℃ and the time is 2-3h.

[0015] In a further preferred embodiment, the heat treatment is followed by cooling in ice water.

[0016] The technical solution provided by the present application has the following obvious beneficial effects:

[0017] The steps for processing high-purity aluminum-silicon-copper ingots provided by the present application are simple, easy to operate and easy to implement.

[0018] The high-purity aluminum-silicon-copper target blank obtained by the process provided by the present application has a uniform internal structure, a grain size of less than 150μm and a uniform grain size distribution, and no cracks.

[0019] The process provided by the present application has a simple process flow, a short completion time, low cost and is conducive to industrialized popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The metallographic microscope picture of the target blank obtained in Example 1.

[0021] Figure 2 The metallographic microscope picture of the sample obtained in Comparative Example 1-1.

[0022] Figure 3 The metallographic microscope picture of the target blank obtained in Example 2.

[0023] Figure 4 The metallographic microscope picture of the sample obtained in Comparative Example 2-1.

[0024] Figure 5 The metallographic microscope picture of the target blank obtained in Example 3.

[0025] Figure 6 The metallographic microscope picture of the sample obtained in Comparative Example 3-1.

[0026] Figure 7 The metallographic microscope picture of the sample obtained in Comparative Example 3-2. DETAILED DESCRIPTION

[0027] Aluminum-silicon-copper alloy ingots often have segregation, uneven grain size and cracks, and cannot be used as target material. The present application provides a process for processing high-purity aluminum-silicon-copper alloy ingots, and the processed ingots have a uniform internal structure, a uniform grain size distribution and no cracks, and can be used as target material.

[0028] Specifically, the technical solution provided by the present application is as follows:

[0029] The application discloses a preparation method of a high-purity aluminum silicon copper target blank, which comprises the following steps: sequentially performing heating pretreatment, upsetting forging, multi-directional rolling and heat treatment on a high-purity aluminum silicon copper cast ingot to obtain the high-purity aluminum silicon copper target blank.

[0030] Before the upsetting forging, the high-purity aluminum silicon copper cast ingot is first subjected to heating pretreatment. After the heating pretreatment, the hardness of the high-purity aluminum silicon copper cast ingot is reduced, plastic deformation is easier to be performed, and the broken grains in the plastic deformation process are facilitated. In the specific embodiment of the application, the temperature of the heating pretreatment is 180-250 DEG C, and the time is 2-3 h.

[0031] After the heating pretreatment, the cast ingot is subjected to upsetting forging. It is found through research that, after the upsetting forging, the grain boundaries of the grains of the cast ingot are in a broken state under a metallographic microscope, and it is easier to form fine grains in the subsequent heat treatment process. In the specific embodiment of the application, the upsetting forging is performed for more than or equal to 3 times, and heating pretreatment is performed before each upsetting forging.

[0032] After the upsetting forging, the cast ingot is cooled in ice water. The cooling mode is very important for preparing the target blank with fine grains. The cooling of the cast ingot in ice water can inhibit the recovery of the grain size of the originally broken grains due to the stress increase after the upsetting.

[0033] In the application, the total deformation amount of the high-purity aluminum silicon copper cast ingot after the upsetting forging is more than or equal to 80%. The greater the deformation amount of the upsetting forging, the better the broken effect of the grain boundaries, and the more uniform and fine the grains after the heat treatment, which is more conducive to improving the sputtering rate of the target material.

[0034] After the upsetting forging, the cast ingot is further rolled. The rolling is used to repair the forging marks and make the surface of the target blank smooth, and also used to increase the deformation amount and break the grains to a greater extent. In the specific embodiment of the application, the multi-directional rolling is performed at room temperature, and the number of the multi-directional rolling is more than or equal to 3 times, and the single-pass depression amount is more than or equal to 1 mm. Further, in the specific embodiment of the application, the total deformation amount of the high-purity aluminum silicon copper cast ingot in the multi-directional rolling is 5-10%.

[0035] The cooling mode between the rolling passes is still ice water cooling, which prevents the recovery of the grain size under the action of stress.

[0036] After the rolling, the ingot is further heat treated. During the heat treatment, the broken grains will nucleate and grow, releasing the stress of plastic deformation and preventing the target material from cracking during sputtering. After the heat treatment, the workpiece is still cooled in ice water to prevent the grains from growing again. In the specific embodiment of the present application, the temperature of the heat treatment is 450-500°C. At this heat treatment temperature, the stress in the ingot is released more completely, which is beneficial to avoiding the generation of cracks in the ingot. The time of the heat treatment can be adaptively adjusted according to the effect of the heat treatment. In the specific embodiment of the present application, the time of the heat treatment is 2-3h.

[0037] In general, each technical step in the heating pretreatment-upsetting forging-rolling-heat treatment process adopted in the present application is closely linked, so that the high-purity aluminum silicon copper target blank with uniform composition, uniform grain size and no cracks can be obtained.

[0038] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present application is not limited to the following specific embodiments.

[0039] Unless otherwise defined, all the professional terms used below have the same meaning as generally understood by those skilled in the art. The professional terms used in this paper are only for the purpose of describing the specific embodiments and are not intended to limit the scope of protection of the present application.

[0040] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0041] Example 1

[0042] Forging:

[0043] The high-purity aluminum silicon copper ingot is heated and pretreated at 250°C for 2h, and then upset forging is performed by using an air hammer;

[0044] The number of times of upset forging is 3, and after each upsetting, the ingot is reheated and pretreated before continuing to upset, and then the workpiece is cooled in ice water after forging.

[0045] The total deformation of upset forging is 80%.

[0046] Rolling:

[0047] Room temperature multi-directional rolling is adopted, and the workpiece is cooled in ice water between passes, the single pass reduction amount is controlled to be 1mm, the workpiece is rolled for 3 passes, and the total deformation is 5%.

[0048] Recrystallization heat treatment:

[0049] The workpiece after rolling is heat treated at 450°C for 2h, the workpiece is put into the box furnace after the furnace is raised to the required temperature, and then the workpiece is cooled in ice water after the heat treatment.

[0050] Figure 1 The metallographic microscope picture of the sample shows that the average grain size of the sample is about 66 μm.

[0051] Comparative Example 1-1

[0052] Comparative Example 1-1 differs from Example 1 in that there is no heating pretreatment step before upsetting forging. Figure 2 The metallographic microscope picture of the sample obtained from Comparative Example 1-1 shows that the average grain size of the sample is about 1000 μm.

[0053] Example 2

[0054] Forging:

[0055] The high-purity aluminum-silicon-copper ingot is heated at 200°C for 2 h for heating pretreatment, and then is subjected to upsetting forging by using an air hammer;

[0056] The upsetting forging is performed 4 times, and after each upsetting, the workpiece is heated for reheating pretreatment and then is subjected to upsetting, and the workpiece is cooled by ice water after each forging;

[0057] The total deformation of the upsetting forging is 90%.

[0058] Rolling:

[0059] The workpiece is subjected to multi-pass rolling at room temperature, and is cooled by ice water between passes, the single-pass reduction is controlled to be 1.5 mm, the rolling is performed 4 passes, and the total deformation is 8%.

[0060] Recrystallization heat treatment:

[0061] The workpiece after rolling is heated at 500°C for 2 h, and after the oven is heated to the required temperature, the workpiece is put into the oven, and is cooled by ice water after the heating.

[0062] Figure 3 The metallographic microscope picture of the sample shows that the average grain size of the sample is about 120 μm.

[0063] Comparative Example 2-1

[0064] Comparative Example 2-1 differs from Example 2 only in that the cooling method after forging is natural cooling in air.

[0065] Figure 4 The metallographic microscope picture of the sample obtained from Comparative Example 2-1 shows that the average grain size of the sample is about 165 μm.

[0066] Example 3

[0067] Forging:

[0068] The high-purity aluminum-silicon-copper ingot is heated at 180°C for 3 h for heating pretreatment, and then is subjected to upsetting forging by using an air hammer;

[0069] The upsetting forging is 3 times, and each time is continued after the pre-treatment of reheat and then upsetting, and the ice water cooling after forging.

[0070] The total deformation of upsetting forging is 85%;

[0071] Rolling:

[0072] The room temperature multi-directional rolling is adopted, the ice water cooling is adopted between passes, the single pass down pressure amount is controlled to be 2mm, the rolling is 3 passes, and the total deformation is 10%.

[0073] Recrystallization heat treatment:

[0074] The workpiece after rolling is placed into the box furnace after the box furnace is raised to the required temperature, and the ice water cooling is adopted after the heat preservation.

[0075] Figure 5 The metallographic microscope picture of the sample is obtained, and the average grain size of the sample is about 70μm.

[0076] Comparative Example 3-1

[0077] The difference between Comparative Example 3-1 and Comparative Example 3 is that the heat treatment temperature is 530℃.

[0078] Figure 6 The metallographic microscope picture of the sample obtained in Comparative Example 3-1 is obtained, and the grain size is too large to be counted.

[0079] Comparative Example 3-2

[0080] The difference between Comparative Example 3-2 and Comparative Example 3 is that the heat treatment temperature is 400℃.

[0081] Figure 7 The metallographic microscope picture of the sample obtained in Comparative Example 3-2 is obtained, and the grain boundary is not completely smooth, the stress release is not complete, and the target cracking possibility is increased in the target sputtering process.

[0082] The above only describes the preferred embodiments of the present application, and it should be noted that the ordinary skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method for preparing a high-purity aluminum-silicon-copper target blank, characterized in that, Includes the following steps: The high-purity aluminum-silicon-copper ingot is obtained by sequentially heating and pretreatment, upsetting and forging, multi-directional rolling and heat treatment. The upsetting forging is performed ≥3 times, and a heat pretreatment is performed before each upsetting forging; after the upsetting forging, the total deformation of the high-purity aluminum-silicon-copper ingot is more than 80%; The cooling method for the upsetting forging is ice water cooling; The total deformation during the multi-directional rolling of the high-purity aluminum-silicon-copper ingot is 5-10%; The heat treatment is performed at a temperature of 450~500℃ for 2~3 hours. After heat treatment, it is cooled in ice water.

2. The method for preparing a high-purity aluminum-silicon-copper target blank as described in claim 1, characterized in that, The heating pretreatment temperature is 180~250℃, and the time is 2~3h.

3. The method for preparing a high-purity aluminum-silicon-copper target blank as described in claim 1, characterized in that, The temperature of the multi-directional rolling is room temperature; the number of multi-directional rolling processes is ≥3 times, and the single-pass pressing amount is ≥1mm.

4. The method for preparing a high-purity aluminum-silicon-copper target blank as described in claim 1, characterized in that, The cooling method between the multi-directional rolling passes is ice water cooling.

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