Preparation method and application of silver alloy target material

Abstract

The invention provides a preparation method and application of a silver alloy target material. According to the preparation method disclosed by the invention, a powder metallurgy process is adopted, the mixed powder of the silver powder and the alloy elements is subjected to alloy smelting and water atomization powder preparation, the compact metal ingot is obtained through compression molding and sintering, and the sintered metal ingot is subjected to calendering processing, so that the silver and the alloy target material of the silver with the required size can be obtained. Compared with the silver and alloy smelting ingot forming process, the powder process can efficiently obtain the uniform and fine-grain silver metal target blank, the traditional multi-pass large-deformation forging process is avoided, and alloy elements are evenly distributed. The invention further provides application of the prepared silver alloy target material in preparation of semiconductor devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy targets, and in particular relates to a preparation method and application of a silver alloy target. Background Art

[0002] As semiconductor devices develop towards high power and high integration, heat dissipation has become one of the key factors restricting device performance and reliability. As an important component of semiconductor devices, the backside metallization system can effectively reduce thermal resistance and improve heat dissipation efficiency by depositing a metal film on the device surface, thereby ensuring long-term stable operation of the device. A typical backside metallization system usually consists of an ohmic contact layer, a diffusion barrier layer, and a conductive layer. The conductive layer is located at the outermost layer of the structure and needs to carry large currents during device operation, so it has high requirements for the electrical and thermal conductivity of the material.

[0003] Silver (Ag) is an ideal choice for conductive layer materials due to its excellent electrical and thermal conductivity. Compared with other precious metals (such as gold, platinum, etc.), silver has a cost advantage and is therefore widely used in semiconductor back metallization systems. Currently, common Ag metallization systems include Ti / Ni / Ag, V / Ni / Ag, etc. These systems usually use magnetron sputtering to deposit metal films on the chip surface. The sputtering process has high requirements on the microstructure of the target material. Fine-grained targets can improve sputtering efficiency, and the uniformity of grain size helps to obtain films with consistent thickness distribution, thereby improving device performance and reliability.

[0004] However, there are still many problems in the preparation process of existing silver targets. Currently, silver and its alloy targets on the market are mainly obtained by melting silver ingots and then rolling them. During the smelting process, due to the large difference in density between some alloying elements (such as B, Ni, Ti, etc.) and silver, and the low solid solubility under liquid phase conditions, it is easy to cause uneven distribution of alloying elements, affecting the uniformity of the target. In addition, in order to obtain a fine-grained structure, it is usually necessary to perform multi-pass, multi-directional large-deformation plastic processing on the silver ingot, which not only increases the complexity of the process, but may also cause uneven internal structure of the target material, affecting the quality of the sputtered film. The limitations of the traditional melting-rolling process are mainly reflected in the following aspects: 1. Uneven distribution of alloying elements: During the smelting process, alloying elements are prone to segregation, resulting in uneven target composition, affecting the performance consistency of the sputtered film. 2. Coarse grains: The grain size of cast silver ingots is usually large, and large deformation plastic processing is required to refine the grains, but the process is complicated and it is difficult to ensure the uniformity of the grain size. 3. Low processing efficiency: Multiple rolling passes not only increase production costs, but may also cause stress concentration inside the target material, affecting subsequent processing and sputtering performance.

[0005] Therefore, there is an urgent need to develop a new preparation process to address the shortcomings of traditional melting-rolling methods in silver target production. An ideal process should achieve a uniform distribution of alloying elements while simultaneously obtaining a fine-grained structure, thereby improving the target's sputtering efficiency and film quality. Based on this, the present invention proposes a novel silver target preparation method designed to optimize the target's microstructure and enhance the performance of semiconductor backside metallization systems. Summary of the Invention

[0006] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the present invention provides a method for preparing a silver alloy target material, which adopts a powder metallurgy process to alloy smelting and water atomization powdering of silver powder and a mixed powder of alloy elements, and then sintering the mixture through pressing, forming, and obtaining a densified metal ingot. The sintered metal ingot is then subjected to rolling processing to obtain silver and its alloy target materials of the required size. Compared with the process of smelting silver and its alloys into ingots, the powder process can efficiently obtain uniform and fine-grained silver metal target blanks, avoiding the traditional multi-pass large deformation forging process and making the alloy elements more evenly distributed.

[0007] The present invention also provides a silver alloy target.

[0008] The present invention also provides an application of a silver alloy target in the preparation of semiconductor devices.

[0009] A first aspect of the present invention provides a method for preparing a silver alloy target, comprising the following steps:

[0010] S1: silver powder and alloy element powder are alloyed in a medium frequency induction furnace to obtain a silver alloy liquid;

[0011] S2: introducing the silver alloy liquid into a tundish, the silver alloy liquid flows into an atomizer through the tundish, the silver alloy liquid is broken into metal droplets by atomized water, and forms alloy powder after cooling;

[0012] S3: introducing hydrogen to dry the alloy powder and then cooling it in the furnace;

[0013] S4: The alloy powder processed in step S3 is placed into a mold and hot-pressed and sintered in a vacuum hot-pressing sintering furnace to obtain a silver alloy ingot;

[0014] S5: rolling the silver alloy ingot and then annealing it to obtain the silver alloy target;

[0015] During the rolling process, the voids inside the silver alloy ingot are gradually healed.

[0016] A technical solution in the method for preparing a silver alloy target of the present invention has at least the following beneficial effects:

[0017] This method uses powder metallurgy to smelt and atomize a mixture of silver and alloying elements. This process is followed by compaction, shaping, and sintering to produce a densified ingot. This sintered ingot is then rolled to produce silver and alloy targets of the desired size. Compared to traditional silver and alloy ingot smelting, the powder process efficiently produces uniform, fine-grained silver targets, avoiding the traditional multi-pass, high-deformation forging process and ensuring a more uniform distribution of alloying elements.

[0018] In the present invention, grain size can be expressed by grain size grade, and generally considered fine grains are those with a grain size of 5 to 8. The silver alloy target of the present invention has a grain size greater than grade 7, and "fine grain" means a grain size less than 32 microns.

[0019] Sintered bodies produced by powder metallurgy have high porosity defects but relatively fine grain size. Conventional calendering uses large deformations to break up coarse grains within the smelt, followed by high-temperature heat treatment to achieve a fine-grained structure. The present invention, however, differs from conventional calendering in that the calendering process heals the voids within the sintered body (i.e., the silver alloy ingot), thereby increasing the density of the sintered body.

[0020] The preparation method of the present invention has no clear requirements on the processing deformation amount and the heat treatment temperature. The grain size depends on the particle size of the powder prepared by water atomization and the sintering process.

[0021] Because the present invention eliminates the need for high-deformation forging to break up coarse grains within the smelt, it avoids internal fatigue damage to the metal ingot caused by repeated high-deformation upsetting and forging, which can lead to cracks and affect the overall mechanical properties of the blank. The preparation method also improves the density of the sintered body and has no strict restrictions on alloying elements, making it a relatively simple process for obtaining highly dense, fine-grained silver alloy targets.

[0022] According to some embodiments of the present invention, the purity of the silver powder is 99.99%.

[0023] According to some embodiments of the present invention, in step S1, silver powder and alloying element powders are alloyed in a medium-frequency induction furnace. Argon is used as a shielding gas during the alloy smelting process to prevent alloying element loss. The smelting process ensures that the silver and alloying elements are uniformly mixed in the liquid phase, and the alloy liquid is kept fluid during the water atomization powder preparation process to prevent phenomena such as flotation and segregation of the alloying elements.

[0024] According to some embodiments of the present invention, in step S1, silver powder and alloy element powder are alloyed in a medium frequency induction furnace, and the mass ratio of the silver powder is ≥80%.

[0025] According to some embodiments of the present invention, the alloy element powder includes at least one of Ti powder, Ni powder, Au powder, Cu powder, Zn powder and In powder.

[0026] According to some embodiments of the present invention, the alloy element powder is Ti powder, and the mass ratio of Ag powder to titanium powder is 97:3.

[0027] According to some embodiments of the present invention, the alloy is smelted at a temperature of 1200°C to 1400°C.

[0028] According to some embodiments of the present invention, the alloy smelting temperature is any one of 1250°C, 1300°C, 1350°C, 1400°C, or a range formed by any two of them, such as 1300°C to 1350°C.

[0029] According to some embodiments of the present invention, in step S2, the silver alloy liquid is introduced into a tundish, and the silver alloy liquid flows into an atomizer through a bottom nozzle of the tundish. The water atomization pressure can be set to 30 MPa. The alloy liquid is broken into fine metal droplets by the atomized water and falls into cooling water to form alloy powder.

[0030] According to some embodiments of the present invention, in step S3, hydrogen is introduced to dry the alloy powder and then the alloy powder is cooled in the furnace;

[0031] According to some embodiments of the present invention, in step S3, the atomized gouache obtained in step S2 is first collected and gouache separation is performed.

[0032] According to some embodiments of the present invention, in step S3, the drying time may be 1 hour, followed by cooling in the furnace.

[0033] Powders prepared by water atomization usually have a high oxygen content, and silver oxide usually decomposes above 300°C. The introduction of hydrogen to dry the alloy powder can effectively deoxidize and dry the silver alloy powder.

[0034] According to some embodiments of the present invention, in step S3, the temperature of the drying process is 320°C to 360°C.

[0035] According to some embodiments of the present invention, in step S3, the drying temperature is any one of 320°C, 330°C, 340°C, 350°C, 360°C, or a range formed by any two of them, such as 350°C to 360°C.

[0036] According to some embodiments of the present invention, in step S4, the alloy powder processed in step S3 is placed in a mold and hot-pressed and sintered in a vacuum hot-pressing furnace to obtain a silver alloy ingot;

[0037] The alloy powder processed in step S3 is sieved and can pass through a 200# sieve. The sieved alloy powder can then be placed in The powder is then placed in a cylindrical graphite mold and placed in a vacuum hot-pressing furnace for hot pressing and sintering, followed by cooling in the furnace. Water-atomized powder typically has a large particle size distribution, and sieving can yield alloy powder suitable for sintering. Finer powders have a larger specific surface area, facilitating sintering.

[0038] According to some embodiments of the present invention, in step S4, the vacuum sintering temperature is 580°C to 620°C.

[0039] According to some embodiments of the present invention, in step S4, the vacuum sintering temperature is any one of 580°C, 590°C, 600°C, 610°C, 620°C, or a range formed by any two of them, such as 600°C to 620°C.

[0040] According to some embodiments of the present invention, in step S4, the vacuum sintering heating rate may be 15°C / min, the holding time may be 1 hour, and the axial pressure may be 20 MPa.

[0041] According to some embodiments of the present invention, the rolling process includes multiple passes of transverse rolling or longitudinal upsetting forging.

[0042] According to some embodiments of the present invention, the transverse rolling is performed in multiple passes, and the deformation of a single rolling pass can be 30%, 30% and 15%.

[0043] According to some embodiments of the present invention, in the longitudinal upsetting forging, the deformation amounts of a single forging pass are 25%, 20%, and 20%, respectively.

[0044] According to some embodiments of the present invention, the annealing temperature is 480°C to 520°C.

[0045] According to some embodiments of the present invention, the annealing temperature is any one of 480° C., 490° C., 500° C., 510° C., and 520° C., or a range formed by any two of them, such as 500° C. to 510° C. The holding time may be 2 hours.

[0046] The second aspect of the present invention provides a silver alloy target material, which is prepared by the preparation method of the first aspect of the present invention.

[0047] The silver alloy target material of the present invention has the following significant beneficial effects:

[0048] Small grain size (<32 microns, grain size >7): Through water atomization and powder metallurgy, the coarse grain problem of traditional melting and casting processes is avoided. No large deformation forging is required to break up the grains, and fine grain structure is directly obtained. Fine grains can improve the mechanical properties (such as strength and toughness) of the target material and the uniformity of the coating.

[0049] The alloy elements are evenly distributed, and liquid phase mixing + atomization rapid cooling during smelting prevents element segregation (such as Ti floating). After sintering, the elements are more evenly distributed, which is conducive to the consistency of coating composition.

[0050] It has high density, heals pores through rolling, and effectively closes the pores of the sintered body through multiple rolling or upsetting forging (such as 30% / 25% deformation in a single pass), significantly improves density, and reduces particle splashing or film defects during sputtering.

[0051] The preparation method of the present invention avoids traditional forging defects, omits multiple upsetting and forging processes, reduces the risk of internal fatigue cracks, and improves the mechanical integrity and service life of the target material.

[0052] Hydrogen drying (320–360°C) decomposes silver oxide, reduces oxygen content, reduces oxygen impurities, and improves the purity of the coating.

[0053] It has good compatibility with alloys such as AgTi (97:3), the element ratio is flexibly adjustable (Ag ≥ 80%), and is suitable for multi-element alloy systems (such as AgCuZnIn).

[0054] The target material of the present invention has high density and fine grains, which can increase sputtering rate and reduce arc discharge risk. Its uniform alloy distribution and low porosity help form defect-free and highly adherent functional films (such as semiconductor and display device coatings).

[0055] Furthermore, compared with the melting and forging process, the heat treatment and deformation processing steps are reduced, the cost is reduced, and it is suitable for large-scale production.

[0056] In summary, this target material has the characteristics of fine grain, high density and uniformity, which is suitable for the field of high-performance coating, and the process is more efficient and reliable.

[0057] A third aspect of the present invention provides the use of a silver alloy target in the preparation of semiconductor devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a preparation flow chart of the silver alloy target material of the present invention.

[0059] Figure 2 Schematic diagram of the sampling position of Example 1.

[0060] Figure 3 This is the EDS diagram of the Ag element in Example 1.

[0061] Figure 4 This is the EDS diagram of Ti element in Example 1.

[0062] Figure 5This is a cross-sectional metallographic structure diagram of the silver alloy target material of Example 1.

[0063] Figure 6 Schematic diagram of the sampling position of Example 2. DETAILED DESCRIPTION

[0064] The preparation process of the silver alloy target of the present invention is as follows: Figure 1 shown.

[0065] It should be noted that the fundamental difference between the present invention and conventional calendering treatment lies in the difference in the initial state of the material and the process objectives, which leads to significant differences in the pore healing effect of calendering.

[0066] 1. Differences in the initial state of the material:

[0067] The sintered body (silver alloy ingot) of the present invention features high porosity, fine grains, and controllable pore morphology. Specifically, through water atomization pulverization and vacuum hot pressing sintering, the silver alloy ingot has a grain size of less than 32 microns (grain size > 7). However, the powder metallurgy sintered body still has a certain amount of porosity (typically 5% to 15%). After sintering, the pores are mostly isolated, spherical, or poorly connected pores, rather than crack-like defects.

[0068] Conventional melt-cast ingots, on the other hand, have low porosity but coarse grains, and different defect types. Low porosity but coarse grains refers to the high density (porosity <1%) of silver alloy ingots obtained through conventional melt-casting processes, but with coarse grains (grain size typically <5, with grain size >50 microns) due to slow cooling. Different defect types refer to the defects of melt-cast ingots being primarily dendritic segregation, shrinkage cavities, or macroscopic cracks, rather than uniform micropores in sintered bodies.

[0069] Therefore, the key difference between the sintered body of the present invention and that of conventional processes is that the sintered body of the present invention is characterized by fine grains and micropores, while conventional melt-cast ingots are characterized by coarse grains and low porosity. This difference in initial state determines the different mechanism of rolling.

[0070] 2. The mechanism of action of calendering process:

[0071] The present invention's rolling process focuses on "pore healing," filling pores through plastic flow. Fine-grained sintered bodies experience more active grain boundary sliding and dislocation motion, and during rolling, the plastic deformation of the metal preferentially flows into the pore regions, closing the pores through the cold welding effect. The present invention's multi-pass progressive compaction employs step-by-step rolling (e.g., a single-pass deformation of 30% → 30% → 15%) or upsetting forging (25% → 20% → 20%) to avoid cracking caused by a single large deformation and gradually achieve physical closure of the pores.

[0072] The present invention also has the advantage of low temperature. Since the grains have been refined, no high temperature annealing is required to assist recrystallization. After rolling, only annealing at 480-520°C is required to eliminate residual stress and avoid the recurrence of porosity.

[0073] Conventional rolling, on the other hand, focuses on "crushing coarse grains." This involves crushing the grains through large deformations. The coarse grains of the molten ingot are forcibly crushed through a single deformation pass (such as forging or rolling) exceeding 50%. Plastic deformation is concentrated within the grains (dislocation accumulation) rather than pore closure. High-temperature annealing (>600°C) is also required to promote dynamic recrystallization and refine the grains. This process is temperature-dependent, but high temperatures can cause pore expansion or element segregation.

[0074] In addition, conventional rolling has poor pore healing effect, and the shrinkage cavities or cracks in the molten ingot are mostly macro defects. Rolling can easily cause the defects to expand rather than heal.

[0075] Therefore, the key difference between the calendering process of the present invention and the conventional calendering process is that the calendering of the present invention targets fine-grained + microporous structure and directly closes the pores by using metal plastic flow; while conventional calendering targets coarse-grained + low-pore structure and aims at grain crushing rather than densification.

[0076] 3. From the perspective of microstructure evolution:

[0077] The microscopic process of pore healing in the present invention primarily involves three stages: initial rolling, multi-pass rolling, and annealing. Initial rolling involves the deformation of isolated pores under stress, causing plastic flow of the metal in the pore walls, transforming the pores from spherical to flat. Multi-pass rolling further fills the flat pores with metal flow, where grain boundary migration promotes atomic diffusion and achieves metallurgical bonding of the pores. Annealing involves low-temperature annealing to eliminate internal stress and stabilize the closed pore structure, ultimately achieving a density exceeding 99%.

[0078] During conventional rolling, the plastic deformation of coarse grains is primarily dislocation slip, with energy consumed in intragranular deformation rather than pore closure. Large deformations can easily trigger grain boundary cracking, increasing the risk of new microcracks.

[0079] Therefore, this invention combines the densification function of rolling with the grain refinement advantages of powder metallurgy, overturning the traditional perception that rolling is only used to break up coarse grains. By using the "water atomization powder making → sintering → rolling" process, it replaces the complex "melting → forging → rolling" process, streamlining production.

[0080] Conventional rolling cannot solve the shrinkage problem of molten ingots, but the present invention achieves active pore healing through sintered body rolling. The present invention achieves simultaneous grain refinement and densification, avoiding the "crushing first, then densification" contradiction in traditional processes. The preparation method of the present invention is suitable for targets with high alloy content (such as Ag-Ti97:3), solving the problem of segregation in melt-casting methods. During target sputtering, particle splashing is reduced, significantly improving film uniformity.

[0081] The present invention utilizes the synergistic effect of powder metallurgy fine-grained matrix + calendering pore healing to achieve high density and fine grains that traditional processes cannot achieve at the same time, providing a high-efficiency, low-defect preparation method for silver alloy targets.

[0082] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0083] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0084] Unless otherwise specified, "room temperature" in the present invention means 25°C±5°C.

[0085] Unless otherwise specified, “about” in the present invention means that the allowable error is within ±2%.

[0086] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0087] Example 1

[0088] A silver alloy target was prepared, and the specific steps were as follows:

[0089] S1: Silver powder with a purity of 99.99% and Ti powder as alloying element are mixed in a mass ratio of 97:3, loaded into a graphite crucible, and the alloy is smelted in a medium frequency induction furnace at a melting temperature of 1300°C. Argon is used as a protective gas during the alloy smelting process to prevent the loss of alloying elements;

[0090] S2: The molten silver alloy liquid is introduced into the tundish. The alloy liquid flows into the atomizer through the nozzle at the bottom of the tundish. The water atomization pressure is set to 30 MPa. The alloy liquid is broken into fine metal droplets by the atomized water and falls into the cooling water to form alloy powder.

[0091] S3: Collect the atomized gouache and separate the gouache. The obtained powder is dried by passing hydrogen at a drying temperature of 350°C for 1 hour, and then cooled in the furnace.

[0092] S4: After drying, the alloy powder is sieved and passed through a 200# sieve. The sieved alloy powder is then loaded into The cylindrical graphite mold was placed in a vacuum hot pressing sintering furnace for hot pressing sintering at a temperature of 600°C, a heating rate of 15°C / min, and a holding time of 1 hour. The axial pressure was 20 MPa, and then the mold was cooled in the furnace.

[0093] S5: The sintered silver alloy ingot is taken out from the mold and subjected to multiple passes of transverse rolling to obtain a slab with a size of 170×150×15 mm. The deformation of a single rolling pass is 30%, 30%, and 15%. After rolling, the slab is annealed at an annealing temperature of 500°C and a holding time of 2 h.

[0094] The slab obtained by the above process is sampled by water jet, and the sampling position is as follows: Figure 2 As shown in the figure, the sampling covers multiple locations of the target (such as the edge and center), verifying the overall uniformity. Combined with the data in Table 1, it can be proved that there is no regional segregation or grain abnormality. The intercept method in the "GB / T 6394-2017 Metal Average Grain Size Determination Method" is used to grade the grain size of the sampling area, and EDS is used to analyze the selected area. The observation surface is the RD-ND surface. The grain size in each area of the field of view is shown in Table 1. Figures 3 to 5 As shown, there are no obvious deformed grains in the field of view, and no obvious alloy element segregation and holes in the EDS scanning surface.

[0095] Figure 3 The Ag distribution shows that the silver element is evenly distributed without aggregation or depletion areas.

[0096] Figure 4 The Ti distribution shows that the titanium element is also evenly dispersed without segregation (such as no Ti floating or agglomeration).

[0097] The silver alloy target material of the present invention has a highly uniform distribution of alloying elements due to:

[0098] (1) Liquid phase melting + water atomization rapid cooling to inhibit segregation;

[0099] (2) Hydrogen drying and deoxidation to reduce oxide interference;

[0100] (3) Hot pressing sintering promotes atomic diffusion.

[0101] This solves the problem of element segregation caused by density differences in traditional melting and casting methods (for example, the density difference between Ti and Ag is large, making them easy to float).

[0102] Figure 5 The cross-sectional microstructure of the target material is shown in Figure 1, showing fine equiaxed grains with no apparent porosity or cracks. This indicates that the rolling process successfully healed the porosity in the sintered body (original porosity 5–15%), resulting in a density exceeding 99%. The grain size is consistent with that in Table 1 (<32 μm), and there are no deformed grains, indicating that the rolling process did not introduce new defects.

[0103] Example 2

[0104] A silver alloy target was prepared, and the specific steps were as follows:

[0105] S1: Silver powder with a purity of 99.99% and Ti powder as alloying element are mixed in a mass ratio of 97:3, loaded into a graphite crucible, and the alloy is smelted in a medium frequency induction furnace at a melting temperature of 1300°C. Argon is used as a protective gas during the alloy smelting process to prevent the loss of alloying elements;

[0106] S2: The molten silver alloy liquid is introduced into the tundish. The alloy liquid flows into the atomizer through the nozzle at the bottom of the tundish. The water atomization pressure is set to 30 MPa. The alloy liquid is broken into fine metal droplets by the atomized water and falls into the cooling water to form alloy powder.

[0107] S3: Collect the atomized gouache and separate the gouache. The obtained powder is dried by passing hydrogen at a drying temperature of 350°C for 1 hour, and then cooled in the furnace.

[0108] S4: After drying, the alloy powder is sieved and passed through a 200# sieve. The sieved alloy powder is then loaded into The cylindrical graphite mold was placed in a vacuum hot pressing sintering furnace for hot pressing sintering at a temperature of 600°C, a heating rate of 15°C / min, and a holding time of 1 hour. The axial pressure was 20 MPa, and then the mold was cooled in the furnace.

[0109] S5: Cut the silver alloy ingot horizontally to obtain Silver alloy ingots were subjected to longitudinal upsetting forging, with the deformation of single forging being 25%, 20%, and 20% respectively, to obtain 50mm thick billets, which were subjected to stress relief annealing. The intermediate annealing process was 300℃×1h. After annealing, the billets were cross-rolled, with a single rolling downstroke of 5mm. After each rolling, the billets were rotated 60° and rolled again until a 15mm thick billet was obtained. The final annealing process was 500℃×2h, and the billets were cut and trimmed with a water jet. Silver alloy flat target.

[0110] The target is sampled by water jet, and the sampling position is as follows: Figure 6 As shown in Figure 1, the intercept method in GB / T 6394-2017 Determination of Average Grain Size of Metals was used to grade the grain size of the sampling area, and EDS was used to analyze the selected area. The observation surface was the RD-ND surface. The grain size in the field of view of each area is shown in Table 1. The results showed that there were no obvious deformed grains in the field of view, and no obvious alloy element segregation and holes in the EDS scanning surface.

[0111] Table 1 Grain size of each area sampled in Example 1 and Example 2

[0112]

[0113]

[0114] Comparative Example 1

[0115] In TW103118045, the silver alloy ingot is hot forged after melting, and then cold rolled in multiple passes with reverse direction. The average grain size of the final silver plate is between 33μm and 126μm.

[0116] Comparative Example 2

[0117] In CN118460971A, the silver alloy ingot after smelting is hot forged, hot rolled and heat treated in sequence, and the average grain size of the obtained silver target is 45 μm.

[0118] The silver alloy target material of the present invention has a grain size greater than level 7, and "fine grains" refer to grain sizes less than 32 microns.

[0119] Table 1 lists the grain size grades (G) for different regions. All regions have a grain size of ≥7.5 (corresponding to a grain size of <32 μm), with some regions reaching 9.5 (finer grains, approximately 10–15 μm). Consistent Max / Min values indicate a uniform grain size distribution, with no unusually coarse or fine grains.

[0120] The results in Table 1 demonstrate that the silver alloy target prepared by the present invention has fine and uniformly distributed grains (all better than Grade 7), far exceeding those of Comparative Example 1 (33–126 μm) and Comparative Example 2 (45 μm). The powder metallurgy plus calendering process of the present invention effectively avoids the coarse grain problem of traditional casting and forging processes, achieving grain refinement without relying on large deformation processes.

[0121] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the spirit of the present invention.

Claims

1. A method for preparing a silver alloy target, characterized in that: The following steps are involved: S1: silver powder and alloy element powder are alloyed in a medium frequency induction furnace to obtain a silver alloy liquid; S2: introducing the silver alloy liquid into a tundish, the silver alloy liquid flows into an atomizer through the tundish, the silver alloy liquid is broken into metal droplets by atomized water, and forms alloy powder after cooling; S3: introducing hydrogen to dry the alloy powder and then cooling it in the furnace; S4: The alloy powder processed in step S3 is placed into a mold and hot-pressed and sintered in a vacuum hot-pressing sintering furnace to obtain a silver alloy ingot; S5: rolling the silver alloy ingot and then annealing it to obtain the silver alloy target; During the rolling process, the voids inside the silver alloy ingot are gradually healed.

2. The preparation method according to claim 1, characterized in that In step S1, silver powder and alloy element powder are alloyed in a medium frequency induction furnace, and the mass ratio of the silver powder is ≥80%.

3. The preparation method according to claim 1, characterized in that The alloy element powder includes at least one of Ti powder, Ni powder, Au powder, Cu powder, Zn powder and In powder.

4. The preparation method according to claim 1, characterized in that The alloy is smelted at a temperature of 1200°C to 1400°C.

5. The preparation method according to claim 1, characterized in that In step S3, the drying temperature is 320°C to 360°C.

6. The preparation method according to claim 1, characterized in that In step S4, the vacuum sintering temperature is 580°C to 620°C.

7. The preparation method according to claim 1, characterized in that The rolling process includes multiple passes of transverse rolling or longitudinal upsetting forging.

8. The preparation method according to claim 1, characterized in that The annealing temperature is 480°C to 520°C.

9. A silver alloy target, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the silver alloy target according to claim 9 in the preparation of semiconductor devices.

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