A copper-phosphorus alloy target and its preparation method

Abstract

This invention provides a copper-phosphorus alloy target and its preparation method. The preparation method includes the following steps: sequentially subjecting a copper-phosphorus alloy billet to hot forging, forging and stretching, a first water cooling treatment, a first heat treatment, rolling, a second heat treatment, and a second water cooling treatment to obtain the copper-phosphorus alloy target; the phosphorus content in the copper-phosphorus alloy billet is 400-500 ppm. The preparation method provided by this invention can reduce internal defects in the copper-phosphorus alloy target, avoid abnormal grain structure, refine internal grains, improve grain uniformity, and thus improve the quality and performance of the copper-phosphorus alloy target.

Description

Technical Field

[0001] This invention belongs to the field of target manufacturing, specifically relating to a copper-phosphorus alloy target and its preparation method. Background Technology

[0002] Copper-phosphorus alloy targets are a special material that plays a crucial role in the metallization process of integrated circuits. Copper-phosphorus alloy targets can be used for electroplating copper conductors. The role of phosphorus is to form a black film on the surface of the copper anode during the electroplating process, allowing Cu atoms and ions to pass through while preventing other byproducts from passing through. When the copper-phosphorus alloy has small grains, it can also prevent fine copper particles from detaching from the anode. Furthermore, using high-quality phosphorus-copper anodes results in very uniform phosphorus distribution, fine crystal particles, and a compact structure. The "black phosphorus film" is neither too thick nor too thin, with moderate adhesion, ensuring reliable quality and effectively inhibiting the formation of monovalent copper ions. Due to the fine copper crystals and the moderate and uniform distribution of phosphorus content, there is very little anode sludge, and the anode bag is typically cleaned only every six months or more. This not only improves electroplating production efficiency but also saves on auxiliary raw materials such as anode bags.

[0003] Therefore, the requirements and demands for copper-phosphorus alloy targets are currently quite high. The current preparation methods for copper-phosphorus alloy targets involve multiple steps and technologies, including high-purity metallurgical purification, casting, powder sintering, microstructure control, heterogeneous welding, and optimized design of the target structure. CN 105506340A discloses a method for preparing a copper-phosphorus alloy anode, which includes: placing pure copper in a non-vacuum furnace; heating the non-vacuum furnace to melt the pure copper; performing a first heat treatment after the pure copper has melted; adding phosphorus sealed and coated with pure copper after the first heat treatment; and performing a second heat treatment after adding the phosphorus. This preparation method improves production efficiency, but the need to replenish phosphorus at the end of the preparation process makes it impossible to guarantee the internal microstructure uniformity of the resulting copper-phosphorus alloy anode.

[0004] CN 113857402A discloses a method for preparing a high-purity copper alloy target. The method includes sequentially performing a first forging and stretching treatment, a first heat treatment, a second forging and stretching treatment, a second heat treatment, a third forging and stretching treatment, a fourth forging and stretching treatment, a static pressing treatment, a rolling treatment, and a fourth heat treatment on the billet. While this method can improve the grain uniformity of the high-purity copper alloy target, it is not suitable for copper-phosphorus alloys.

[0005] In summary, how to provide a method for preparing copper-phosphorus alloy targets that reduces internal defects in copper targets, avoids abnormal grain structure, improves grain refinement, and thus improves the quality and performance of copper-phosphorus alloy targets has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a copper-phosphorus alloy target and its preparation method. The preparation method can reduce internal defects of the copper-phosphorus alloy target, avoid abnormal grain structure, refine internal grains, improve grain uniformity, and thus improve the quality and performance of the copper-phosphorus alloy target.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a copper-phosphorus alloy target, the method comprising the following steps:

[0009] The copper-phosphorus alloy billet is subjected to hot forging, forging and stretching, first water cooling, first heat treatment, rolling, second heat treatment and second water cooling in sequence to obtain the copper-phosphorus alloy target material.

[0010] The phosphorus content in the copper-phosphorus alloy billet is 400-500 ppm.

[0011] This invention processes raw copper-phosphorus alloy billets into high-quality copper-phosphorus alloy targets through a series of steps including hot forging, forging stretching, two heat treatments, and rolling. The forging stretching process breaks down the original coarse dendritic and columnar grains into fine grains, compacting and welding segregation, porosity, pores, and inclusions within the copper-phosphorus alloy billet, resulting in a denser microstructure. The heat treatment process eliminates residual stress caused by extrusion within the copper-phosphorus alloy billet, appropriately reducing the hardness and brittleness of the resulting copper target, increasing its plasticity, reducing deformation and cracking tendency in subsequent processes, and further improving grain size uniformity.

[0012] Furthermore, by incorporating a rolling process between the first and second heat treatments, this invention not only aims to press the raw material into a target material of a specific shape, but also facilitates pressing after the initial grain refinement during the first heat treatment. This avoids overall cracking of the target blank caused by pressing before the first heat treatment. Pressing before the second heat treatment effectively prevents the difficulty in controlling the pressed shape after further grain refinement following the second heat treatment. Moreover, the pressing step effectively fills new pores and cracks that appear after grain refinement and microstructure adjustment following the first heat treatment, which is also beneficial for optimizing the target material's performance.

[0013] As a preferred embodiment of the present invention, the temperature of the hot forging treatment is 480 to 520°C, for example, it can be 480°C, 485°C, 490°C, 495°C, 500°C, 505°C, 510°C, 515°C or 520°C, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0014] Preferably, the holding time for the hot forging treatment is 50 to 80 minutes, for example, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes or 80 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] In this invention, the function of hot forging is as follows: hot forging at a certain temperature not only changes the shape of the ingot and destroys the original coarse grains, but also makes the copper-phosphorus alloy less prone to cracking. If the temperature is too high, the grains after forging will be too large, and the grain structure cannot be effectively controlled, resulting in the grains becoming larger when they are re-formed during heat treatment. If the temperature is too low, the copper-phosphorus alloy will crack due to deformation during forging, or the deformation will be insufficient, failing to meet the requirements for grain breakage.

[0016] As a preferred embodiment of the present invention, the forging process includes sequential drawing and upsetting.

[0017] Preferably, the lengthening to 180-200% of the original copper-phosphorus alloy billet length, for example, can be 180%, 184%, 188%, 192%, 196% or 200%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the upsetting is to 80% to 100% of the length of the original copper-phosphorus alloy billet, for example, 80%, 84%, 88%, 92%, 96% or 100%, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] In this invention, the purpose of the forging and stretching process is to break the original coarse dendritic grains and columnar grains into fine grains.

[0020] As a preferred embodiment of the present invention, the temperature of the first heat treatment is 335 to 365°C, for example, it can be 335°C, 340°C, 345°C, 350°C, 355°C, 360°C or 365°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the holding time of the first heat treatment is 110 to 130 minutes, for example, it can be 110 minutes, 114 minutes, 118 minutes, 122 minutes, 126 minutes or 130 minutes, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0022] As a preferred embodiment of the present invention, the rolling temperature is 20 to 30°C, for example, 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the deformation amount of the rolling process is 60-70%, for example, it can be 60%, 62%, 64%, 66%, 68% or 70%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] As a preferred embodiment of the present invention, the temperature of the second heat treatment is 580 to 620°C, for example, it can be 580°C, 585°C, 590°C, 595°C, 600°C, 605°C, 610°C, 615°C or 620°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] Preferably, the holding time of the second heat treatment is 50 to 70 minutes, for example, 50 minutes, 54 minutes, 58 minutes, 62 minutes, 66 minutes or 70 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] As a preferred embodiment of the present invention, the process between the first heat treatment and the rolling process further includes: removing edge material.

[0027] It is worth noting that the removal of edge material described in this invention refers to removing the defective portions at both ends of the blank.

[0028] As a preferred embodiment of the present invention, the temperature of the first water cooling treatment is 20 to 30°C, for example, it can be 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the first water cooling treatment time is 15-20 minutes, for example, it can be 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the temperature of the second water cooling treatment is 20 to 30°C, for example, it can be 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the second water cooling treatment time is 15-20 minutes, for example, it can be 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] The preparation method of the present invention further includes: taking a sample of the target material after the second water cooling treatment for metallographic analysis, and then performing mechanical processing such as rolling to obtain the target target material.

[0033] As a preferred embodiment of the present invention, the method for preparing the copper-phosphorus alloy target provided in the first aspect of the present invention includes sequentially processing a copper-phosphorus alloy billet with a phosphorus content of 400-500 ppm:

[0034] Hot forging treatment: The temperature of the hot forging treatment is 480-520℃, and the holding time is 50-80 min;

[0035] Forging and stretching process: The forging and stretching process involves first drawing the billet to 180-200% of its original length, and then upsetting it to 80-100% of its original length.

[0036] First water cooling treatment: The temperature of the first water cooling treatment is 20-30℃, and the time is 15-20 minutes;

[0037] First heat treatment: The temperature of the first heat treatment is 335-365℃, and the holding time is 110-130 min;

[0038] Rolling treatment: The deformation amount of the rolling treatment is 60-70%;

[0039] Second heat treatment: The temperature of the second heat treatment is 580-620℃, and the holding time is 50-70 min;

[0040] Second water cooling treatment: The temperature of the second water cooling treatment is 20-30℃, and the time is 15-20 minutes.

[0041] Secondly, the present invention provides a copper-phosphorus alloy target material, which is prepared by the method for preparing copper-phosphorus alloy targets provided in the first aspect.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The preparation method provided by the present invention can reduce the internal defects of the copper-phosphorus alloy target, avoid abnormal grain structure, refine the internal grains, improve grain uniformity, and thus improve the quality and performance of the copper-phosphorus alloy target.

[0044] (2) The preparation method provided by the present invention is simple and low in cost. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] Example 1

[0047] This embodiment provides a copper-phosphorus alloy target material, the preparation method of which includes sequentially processing a copper-phosphorus alloy billet with a phosphorus content of 450 ppm:

[0048] Hot forging treatment: The temperature of the hot forging treatment is 500℃, and the holding time is 60min;

[0049] Forging and stretching process: The forging and stretching process involves first drawing the billet to 190% of its original length, and then upsetting it to 90% of its original length.

[0050] First water cooling treatment: The temperature of the first water cooling treatment is 25℃, and the time is 17.5min;

[0051] First heat treatment: The temperature of the first heat treatment is 350℃, and the holding time is 120min;

[0052] Rolling treatment: The deformation amount of the rolling treatment is 65%;

[0053] Second heat treatment: The temperature of the second heat treatment is 600℃, and the holding time is 60min;

[0054] Second water cooling treatment: The temperature of the second water cooling treatment is 25℃ and the time is 17.5min.

[0055] Example 2

[0056] This embodiment provides a copper-phosphorus alloy target material, the preparation method of which includes sequentially processing a copper-phosphorus alloy billet with a phosphorus content of 500 ppm:

[0057] Hot forging treatment: The temperature of the hot forging treatment is 480℃, and the holding time is 80min;

[0058] Forging and stretching process: The forging and stretching process involves first drawing the billet to 180% of its original length, and then upsetting it to 80% of its original length.

[0059] First water cooling treatment: The temperature of the first water cooling treatment is 20℃, and the time is 20min;

[0060] First heat treatment: The temperature of the first heat treatment is 335℃, and the holding time is 130min;

[0061] Rolling treatment: The deformation amount of the rolling treatment is 60%;

[0062] Second heat treatment: The temperature of the second heat treatment is 580℃, and the holding time is 70min;

[0063] Second water cooling treatment: The temperature of the second water cooling treatment is 20℃ and the time is 20min.

[0064] Example 3

[0065] This embodiment provides a copper-phosphorus alloy target material, the preparation method of which includes sequentially processing a copper-phosphorus alloy billet with a phosphorus content of 400 ppm:

[0066] Hot forging treatment: The temperature of the hot forging treatment is 520℃, and the holding time is 50min;

[0067] Forging and stretching process: The forging and stretching process involves first drawing the billet to 200% of its original length, and then upsetting it to 100% of its original length.

[0068] First water cooling treatment: The temperature of the first water cooling treatment is 30℃, and the time is 15min;

[0069] First heat treatment: The temperature of the first heat treatment is 365℃, and the holding time is 110min;

[0070] Rolling treatment: The deformation amount of the rolling treatment is 70%;

[0071] Second heat treatment: The temperature of the second heat treatment is 620℃, and the holding time is 50min;

[0072] Second water cooling treatment: The temperature of the second water cooling treatment is 30℃ and the time is 15min.

[0073] Example 4

[0074] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0075] In this embodiment, the temperature of the hot forging process is adjusted to 450°C.

[0076] Example 5

[0077] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0078] In this embodiment, the temperature of the hot forging process is adjusted to 550°C.

[0079] Example 6

[0080] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0081] In this embodiment, the forging and stretching process is adjusted as follows: first, the billet is drawn to 150% of its original length, and then it is uptaken to 50% of its original length.

[0082] Example 7

[0083] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0084] In this embodiment, the forging and stretching process is adjusted as follows: first, the billet is drawn to 200% of its original length, and then it is uptaken to 150% of its original length.

[0085] Example 8

[0086] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0087] In this embodiment, the temperature of the first heat treatment is adjusted to 300°C.

[0088] Example 9

[0089] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0090] In this embodiment, the temperature of the first heat treatment is adjusted to 400℃.

[0091] Example 10

[0092] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0093] In this embodiment, the temperature of the second heat treatment is adjusted to 520°C.

[0094] Example 11

[0095] This embodiment provides a copper-phosphorus alloy target material, the only difference between the preparation method of the copper-phosphorus alloy target material and that of Embodiment 1 is:

[0096] In this embodiment, the temperature of the second heat treatment is adjusted to 660°C.

[0097] Comparative Example 1

[0098] This comparative example provides a copper-phosphorus alloy target, the preparation method of which differs from that of Example 1 only in that:

[0099] The second heat treatment process is omitted in this comparative example.

[0100] Comparative Example 2

[0101] This comparative example provides a copper-phosphorus alloy target, the preparation method of which differs from that of Example 1 only in that:

[0102] This comparative example adds a forging and stretching process before the second heat treatment. The forging and stretching process is as follows: first, the billet is drawn to 200% of the original copper-phosphorus alloy billet length, and then it is upheaded to 100% of the original copper-phosphorus alloy billet length.

[0103] Comparative Example 3

[0104] This comparative example provides a copper-phosphorus alloy target, the preparation method of which differs from that of Example 1 only in that:

[0105] The rolling process is omitted in this comparative example.

[0106] Comparative Example 4

[0107] This comparative example provides a copper-phosphorus alloy target, the preparation method of which differs from that of Example 1 only in that:

[0108] The phosphorus content in the copper-phosphorus alloy billet described in this comparative example was adjusted to 800 ppm.

[0109] Comparative Example 5

[0110] This comparative example provides a copper-phosphorus alloy target, the preparation method of which differs from that of Example 1 only in that:

[0111] In this comparative example, the phosphorus content in the copper-phosphorus alloy billet was adjusted to 200 ppm.

[0112] The performance of the copper-phosphorus alloy targets provided in the above embodiments and comparative examples was tested, and the results are shown in Table 1:

[0113] The method for detecting the uniformity of the microstructure includes: using a conductivity meter to characterize the internal microstructure uniformity of the copper-phosphorus alloy target; the greater the fluctuation in conductivity, the worse the uniformity of the target; generally, fluctuations exceeding ±10% are considered to indicate non-uniform microstructure, while fluctuations not exceeding ±10% are considered to indicate uniform microstructure; testing the conductivity fluctuations of N targets, with uniformity calculated as (number of uniform targets / N) × 100%; and using C-SCAN, employing ultrasonic flaw detection principles, to achieve qualitative, locational, quantitative, and non-destructive evaluation of defects.

[0114] Table 1

[0115] Average grain size / μm Tissue homogeneity / % Are there any defects? Example 1 65.7 99 none Example 2 68.2 99 none Example 3 67.3 99 none Example 4 105.0 90 none Example 5 120.2 93 none Example 6 130.5 90 exist Example 7 111.3 5 none Example 8 120.2 90 none Example 9 150.5 88 none Example 10 210.2 89 none Example 11 270.5 85 none Comparative Example 1 420.5 20 exist Comparative Example 2 - - - Comparative Example 3 505.2 0 exist Comparative Example 4 50 80 none Comparative Example 5 130 80 none

[0116] Based on Table 1, the following points can be concluded:

[0117] (1) Comprehensive analysis of Examples 1-3 shows that the copper-phosphorus alloy target material obtained by the preparation method provided by the present invention has a smaller micro-grain size, a more uniform internal structure, and no internal defects.

[0118] (2) Comprehensive analysis of Examples 1 and Examples 4-11 shows that changes in the process parameters of each step in the preparation method of the present invention will affect the uniformity of the target material or the grain size.

[0119] When the temperature of the hot forging process is too high, the grains will become larger; when the temperature is too low, the uniformity will be poor.

[0120] When the elongation or upsetting ratio is reduced during the forging and stretching process, it will result in insufficient grain breakage and excessively large grains; if the upsetting ratio is increased, it will lead to defects in the alloy.

[0121] If the temperature of the first heat treatment is too high, the grains will be too large; if the temperature is too low, the grains will not crystallize completely.

[0122] If the temperature of the second heat treatment is too high, the grains will be too large; if the temperature is too low, the grains will not crystallize completely.

[0123] (3) Comprehensive analysis of Example 1 and Comparative Examples 1-3 shows that adjusting the process in the preparation method of the present invention will affect the uniformity of the structure or the grain size of the obtained target material.

[0124] Omitting the second heat treatment process will result in grains not crystallizing; omitting the rolling process will result in defects; adding a secondary forging process will result in alloy breakage.

[0125] (4) Comprehensive analysis of Example 1 and Comparative Examples 4-5 shows that the determination of process parameters in the preparation method provided by the present invention is only applicable to copper-phosphorus alloys with a phosphorus content of 400-500 ppm.

[0126] When the phosphorus content is too high, it will result in grains that are too small; when the phosphorus content is too low, it will result in grains that are too large.

[0127] In summary, the preparation method provided by the present invention can reduce internal defects of the copper-phosphorus alloy target, avoid abnormal grain structure, refine internal grains, improve grain uniformity, and thus improve the quality and performance of the copper-phosphorus alloy target.

[0128] The applicant declares that the detailed process equipment and process flow of this invention are illustrated through the above embodiments, but this invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that this invention must rely on the above detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

Claims

1. A method for preparing a copper-phosphorus alloy target, characterized in that, The preparation method includes the following steps: The copper-phosphorus alloy billet is subjected to hot forging, forging and stretching, first water cooling, first heat treatment, rolling, second heat treatment and second water cooling in sequence to obtain the copper-phosphorus alloy target material. The phosphorus content in the copper-phosphorus alloy billet is 400~500ppm; The hot forging temperature is 480~520℃, and the holding time of the hot forging is 50~80min; The forging process includes sequential drawing and upsetting, wherein the drawing is performed to 180-200% of the original copper-phosphorus alloy billet length, and the upsetting is performed to 80-100% of the original copper-phosphorus alloy billet length. The temperature of the first heat treatment is 335~365℃, and the holding time is 110~130min; The rolling temperature is 20~30℃, and the deformation amount of the rolling process is 60~70%. The second heat treatment temperature is 580~620℃, and the holding time is 50~70min.

2. The preparation method according to claim 1, characterized in that, Between the first heat treatment and the rolling process, the process further includes: removing edge material.

3. The preparation method according to claim 1, characterized in that, The temperature of the first water cooling treatment is 20~30℃.

4. The preparation method according to claim 1, characterized in that, The first water cooling treatment takes 15 to 20 minutes.

5. The preparation method according to claim 1, characterized in that, The temperature of the second water cooling treatment is 20~30℃.

6. The preparation method according to claim 1, characterized in that, The second water cooling process takes 15-20 minutes.

7. The preparation method according to claim 1, characterized in that, The preparation method includes sequentially processing a copper-phosphorus alloy billet with a phosphorus content of 400-500 ppm: Hot forging treatment: The temperature of the hot forging treatment is 480~520℃, and the holding time is 50~80min; Forging and stretching process: The forging and stretching process involves first drawing the billet to 180-200% of its original length, and then upsetting it to 80-100% of its original length. First water cooling treatment: The temperature of the first water cooling treatment is 20~30℃, and the time is 15-20min; First heat treatment: The temperature of the first heat treatment is 335~365℃, and the holding time is 110~130min; Rolling treatment: The deformation amount of the rolling treatment is 60~70%; Second heat treatment: The temperature of the second heat treatment is 580~620℃, and the holding time is 50~70min; Second water cooling treatment: The temperature of the second water cooling treatment is 20~30℃, and the time is 15-20min.