CN114015989A

CN114015989A - Silver-scandium alloy sputtering target material and preparation method thereof

Info

Publication number: CN114015989A
Application number: CN202111181429.1A
Authority: CN
Inventors: 曾墩风; 王志强; 石煜
Original assignee: Wuhu Yingri Technology Co ltd
Current assignee: Wuhu Yingri Technology Co ltd
Priority date: 2021-10-11
Filing date: 2021-10-11
Publication date: 2022-02-08

Abstract

The invention relates to a silver-scandium alloy sputtering target material and a preparation method thereof, wherein the silver-scandium alloy sputtering target material is prepared from the following raw materials in parts by mass: 96.90-99.85 parts of Ag and 0.10-3.00 parts of Sc; the material can also comprise 0.05-0.15 parts of doping elements by mass, wherein the doping elements are selected from one or two of Ce, Pr, Zr, La and Nb. The preparation method of the silver-scandium alloy sputtering target material comprises the steps of ingot smelting, heating, rolling, heat treatment, shaping, machining, binding and the like. According to the invention, scandium alloy is added into the silver base, so that the sulfuration resistance and heat resistance of the silver base target material can be effectively improved; on the basis, the size of crystal grains can be further reduced and the comprehensive performance of the target material can be improved by adding other doping elements. The technical effects are obtained as a result of the comprehensive effect of a plurality of technical means such as product formula, preparation method and the like.

Description

Silver-scandium alloy sputtering target material and preparation method thereof

Technical Field

The invention relates to a silver-based alloy, in particular to a silver-based alloy for preparing a sputtering target material.

Background

The target material is a basic material in the magnetron sputtering process, the usage amount is large, and the quality of the target material plays a crucial role in determining the performance of the film. The target material has wide application fields, and mainly comprises an optical target material, a target material for a display film, a target material for the semiconductor field, a target material for a recording medium, a superconducting target material and the like. Among them, the target material for semiconductor field, the target material for display and the target material for recording medium are three major target materials which are currently most widely used. In order to increase the film preparation rate and ensure the growth quality of the film, the sputtering target material needs to meet certain index requirements. In the prior art, key factors for controlling the quality of a target material are summarized into aspects of purity, density, strength, grain size, size distribution and the like.

Silver has excellent performances of high reflectivity, low extinction coefficient, high thermal conductivity, low resistivity, good surface smoothing effect and the like, and is plated on a substrate by a magnetron sputtering technology to prepare a silver-based alloy film which is used for producing an electrode film or a reflecting layer film of a liquid crystal display, an optical recording medium and low-emissivity glass. The silver-based film is easy to be exposed with H on the surface under high-temperature and high-humidity environment or in the air for a long time₂S reacts to form a yellow, brown or brown silver sulfide film or an oxide film with oxygen, which causes significant performance degradation and is also subject to SO in the environment₂And chloride ions, which reduces the reflectance of silver. Further, the thin film is liable to cause phenomena such as growth of silver crystal grains and aggregation of silver atoms, which leads to deterioration in conductivity and reflectance, and deterioration in adhesion to the substrate.

Therefore, how to improve the weather resistance of the silver-based alloy film becomes a difficult problem to be solved urgently in the technical field on the premise of keeping the excellent performance of the silver-based alloy film. At present, the solution in the prior art is to modify the surface of the silver alloy or add alloying elements to improve the weather resistance of the silver alloy, but the film generated by the former is thin, and the exposed alloy still changes color after being scratched. Therefore, the addition of alloying elements is a better choice for improving the performance of silver-based films. For example, the Chinese non-patent document "synergistic effect of Au and Ge on the sulfuration resistance of silver-based alloy target blank" (Zhang Sheng, Zhang Dun, Yanghong, rare metal material and engineering [ J ], vol.48, No. 3, 2019: 987-. The above methods focus on resistance to vulcanization and do not give sufficient attention to heat resistance. In addition, the method is only one of the solutions to the technical problem, and there may be more alternative technical solutions in the real world to be further researched and developed by those skilled in the art.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a novel silver-based alloy sputtering target material, so that a film sputtered by the target material has higher weather resistance and excellent comprehensive performance.

The invention aims to solve another technical problem of providing a preparation method of a silver-scandium alloy sputtering target material, aiming at preparing the target material by the method and enabling the product to reach the standard.

In order to solve the technical problems, the invention adopts the following technical scheme:

the silver-scandium alloy sputtering target material is prepared from the following raw materials in parts by mass: 96.90-99.85 parts of Ag and 0.10-3.00 parts of Sc.

Scandium is added into the silver base, so that coarsening of crystal grains can be inhibited, the size of the crystal grains is more uniform, and the size range of the crystal grains is 3-20 mu m; the sulfur resistance and heat resistance of the silver-based alloy can be significantly enhanced (see the following test examples).

Furthermore, the raw materials for preparing the target material also comprise 0.05-0.15 parts by mass of doping elements, wherein the doping elements are selected from one or two of Ce, Pr, Zr, La and Nb.

Furthermore, the doping elements are Ce and Pr, wherein the Ce accounts for 0.05 part, and the Pr accounts for 0.05 part.

Furthermore, in order to ensure the purity of the finished product, the purities of Ag, Sc, Ce, Pr, Zr, La and Nb are all more than or equal to 4N.

Other doping elements are added into the silver-based alloy, so that coarsening of crystal grains can be further inhibited, and the comprehensive performance of the silver-scandium alloy sputtering target can be further improved.

The preparation method of the silver-scandium alloy sputtering target comprises the following steps:

s1 smelting and ingot casting: weighing the raw materials according to the formula, and smelting; and injecting the smelted liquid into a carbonaceous casting mold, casting into an Ag alloy spindle, and carrying out vacuum protection in the ingot casting process.

Further, the smelting method mainly comprises two methods:

one method is high-frequency smelting furnace smelting, and the specific method comprises the following steps: charging raw materials into a carbonaceous crucible, placing into a high-frequency melting furnace, vacuumizing, introducing 1.5-8 × 10⁴The temperature of the atmosphere Pa Ar is gradually increased to 1855 ℃ of 1400 ℃ and is kept for 20-30 min. Further, the melting temperature was gradually increased to 1800 ℃ and maintained for 25 min.

In the method, the smelting temperature and the atmosphere are specially designed, so that the performance of the product can be further improved.

The other method is magnetic suspension smelting, and the specific method comprises the following steps: weighing raw materials, putting into a crucible of a water-cooled crucible magnetic suspension smelting furnace, vacuumizing to-0.08 MPa, filling Ar gas until the pressure is 0, maintaining the pressure for 30s, and repeatedly pumping and filling for 3 times; turning on a high-frequency power supply, gradually increasing the heating power by 0.5kw every 1min from 2.0kw until a continuously flowing spherical metal liquid appears in the crucible, increasing the heating power by 1kw every 0.5min, stopping increasing the heating power when the temperature reaches 8kw, preserving the heat for 5min, cooling, and taking out a coarse ingot; putting the coarse ingot into the crucible again, and repeating the smelting process for 1-3 times; and during the last smelting, after the heat preservation is finished, injecting the smelted liquid into a carbonaceous casting mold while the liquid is hot.

In the magnetic suspension smelting technology, an induction coil is additionally arranged outside a water-cooled crucible and then the water-cooled crucible can be electrified to work, and metal materials in the crucible generate eddy current under the action of a high-frequency magnetic field, so that the metal materials are heated and melted. Because the direction of the vortex at the contact part of the outer side of the metal material and the crucible wall is opposite to the direction of the vortex on the inner wall of the crucible flap, a repulsive force is generated between the metal and the crucible wall; when the metal material is completely melted, the molten metal is suspended in the middle of the crucible under the action of thrust force, so that the molten metal is separated from the crucible. The silver-based alloy ingot prepared by the method has higher purity; because the molten metal is separated from the crucible, the heat loss is less, the temperature is uniform, the burning loss of the alloy is reduced, and the components in the alloy are more accurate.

Heating: and putting the Ag alloy spindle into a heating furnace, heating, gradually raising the temperature, keeping the temperature for 3-5 hours at the highest temperature not exceeding 800 ℃.

Rolling: and carrying out three-pass fine hot rolling, water cooling and cold rolling.

Further, the rolling steps are as follows:

s3-1 finish hot rolling: fine hot rolling for three times, wherein the rolling rate of each pass is 20-45%, and the strain rate is 6-12%/s; the temperature of the plate after three times is 500-700 ℃;

s3-2 water cooling: quenching from the temperature of 500-700 ℃ at the cooling speed of 300 ℃/min;

s3-3 cold rolling: performing cold rolling for at least one pass; the rolling rate of each pass is 25-40%, and the average value of strain speed is 5-9%/s; cold rolling to the required plate thickness; the temperature of the cold-rolled sheet is below 150 ℃.

The rolling procedure is specially designed, so that the crystal grains of the alloy can be further refined, and the defects of the microstructure are eliminated, so that the structure of the alloy material is compact, and the mechanical property is improved.

Further, Y-stabilized ZrO was used in both rolling (hot rolling and cold rolling)₂The wear-resistant ceramic roller avoids introducing other impurity elements while ensuring the flatness of the target blank, thereby ensuring the purity of the silver-based alloy.

And (3) heat treatment: keeping the temperature at 500 ℃ for 5-8 hours at 300-.

Shaping: and (5) correcting the shape by adopting a straightening machine.

And (3) machining: and processing the blank into a required size to obtain the Ag-based alloy target blank.

Regarding the machining method and the specific dimensions, those skilled in the art can make routine selections according to the needs, and are not particularly limited herein.

Binding: binding the target embryo on the backboard to obtain the target embryo.

Regarding the binding method, those skilled in the art can make routine selections as required, and the method is not limited herein.

Compared with the prior art, the beneficial technical effects of the invention can be embodied in at least the following aspects:

1. the silver-scandium alloy sputtering target material has small and uniform grain size

As can be seen from comparison of the data of the experimental examples below, the grain size decreases from 5-40 μm to 3-20 μm (Ag-Sc) and 3-15 μm (Ag-Sc-doping element) with addition of scandium to the silver base.

Scandium added into silver can improve the sulfuration resistance of the silver-based target material

As can be seen from the comparison of the data in the following test examples, scandium is added to the silver base, and the target material is in H₂In the S corrosion accelerated test, the color of the silver target material is not changed after 2 hours, and the silver target material is far superior to a pure silver target material.

The addition of scandium to silver improves the heat resistance of the silver-based film

As can be seen from the comparison of the data in the test examples below, the reflectance of the silver-based alloy thin film prepared by adding scandium to silver was much lower than that of the pure silver thin film when the silver-based alloy thin film was placed in a nitrogen atmosphere at 250 ℃ for 2 hours.

Other doping elements are added into the silver-based alloy, so that the size of crystal grains can be further reduced, and the comprehensive performance of the target material can be improved

5. The silver-based alloy ingot prepared by adopting the magnetic suspension smelting technology has high purity and accurate components

The silver-based alloy ingot is prepared by the magnetic suspension smelting technology, so that the purity is higher; because the molten metal is separated from the crucible, the heat loss is less, the temperature is uniform, the burning loss of the alloy is reduced, and the components in the alloy are more accurate.

Using ZrO in rolling₂Wear-resistant ceramic roller capable of verifying the purity of silver-based alloy

Y-stable ZrO2 wear-resistant ceramic rollers are used during rolling (hot rolling and cold rolling), so that the flatness of a target blank is ensured, and other impurity elements are prevented from being introduced, thereby ensuring the purity of the silver-based alloy.

In conclusion, in order to improve the weather resistance and comprehensive performance of the silver-based film, the invention provides the novel silver-scandium alloy sputtering target material, and the sulfidation resistance and heat resistance of the silver-based target material can be effectively improved by adding the alloy element scandium into the silver base; on the basis, the size of crystal grains can be further reduced and the comprehensive performance of the target material can be improved by adding other doping elements. The technical effects are obtained as a result of the comprehensive effect of a plurality of technical means such as product formula, preparation method and the like.

Test example Performance test of silver-scandium alloy sputtering target

1. Test method

The silver-scandium alloy sputtering target material prepared in the following examples and the pure silver sputtering target material prepared in the comparative example are respectively subjected to performance tests by adopting the following methods:

1.1 testing of the resistance to vulcanization

Placing the target material in H₂The color change was observed in an S atmosphere for 2 hours.

Reflectance test

Preparation of a film sample: and preparing the target materials into silver-based alloy films with the thickness of 200nm by adopting a magnetron sputtering method. The process conditions of magnetron sputtering are as follows: the sputtering power is 300W, the sputtering pressure is 0.8Pa, the deposition temperature Rt and the sputtering time length is 20 min.

The reflectance of each film sample at a wavelength of 600nm was measured using an ultraviolet-visible spectrophotometer.

Heat resistance test

The film samples prepared according to method 1.2 were tested for reflectivity, designated reflectance (prepared), and placed in a nitrogen atmosphere at 250 ℃ for 2 hours, tested for reflectivity, designated reflectance (heat treated). The heat resistance of the film samples was examined by comparing the change in reflectance.

Grain size and uniformity test

And observing the grain size and uniformity of the alloy target by adopting a scanning electron microscope.

Test results

The test results are shown in Table 1.

TABLE 1 Performance testing of silver-scandium alloy sputtering targets

The results show that: (1) the silver-scandium alloy sputtering target material has small and uniform grain size; (2) scandium is added into silver, so that the sulfuration resistance of the silver-based target material can be improved; (3) scandium is added into silver, so that the heat resistance of the silver-based film can be improved; (4) other doping elements are added into the silver-based alloy, so that the size of crystal grains can be further reduced, and the comprehensive performance of the target material can be improved.

Detailed Description

The technical solution of the present invention is further described below with reference to examples.

EXAMPLE preparation of silver-scandium alloy sputtering target

The formula is as follows: see table 1 above for details.

The preparation method comprises the following steps:

Further, the smelting method mainly comprises two methods.

The rolling steps are as follows:

ZrO used in rolling (both hot rolling and cold rolling)₂Wear-resistant ceramic roller.

Shaping: and (5) correcting the shape by adopting a straightening machine.

Specific preparation of examples 1-8 are detailed in Table 1 above.

The specific preparation of the comparative examples is detailed in table 1 above.

It should be understood that the above examples are only for clearly illustrating the technical solutions and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. a silver-scandium alloy sputtering target material, is characterized in that, described target material is prepared from the raw material of following mass fraction:

Ag: 96.90-99.85 parts, Sc: 0.10-3.00 parts.

2 . The silver-scandium alloy sputtering target according to claim 1 , wherein the raw materials for preparing the target further include doping elements in parts by mass of 0.05-0.15 parts, and the doping The element is selected from one or two of Ce, Pr, Zr, La, and Nb.

3 . The silver-scandium alloy sputtering target according to claim 2 , wherein the doping elements are Ce and Pr, wherein Ce: 0.05 part, Pr: 0.05 part. 4 .

4. the preparation method of the silver-scandium alloy sputtering target material described in any one of claim 1-3, is characterized in that, described preparation method comprises the steps:

S1 Smelting ingot: Weigh each raw material according to the formula and smelt; inject the smelted liquid into the carbon casting mold, and cast it into an Ag alloy ingot. The ingot casting process adopts vacuum protection;

S2 Heating: Put the Ag alloy ingot into the heating furnace, heat it, gradually increase the temperature, the maximum temperature does not exceed 800 °C, and the holding time is 3-5 hours;

S3 rolling: three passes of finishing hot rolling, water cooling, and then cold rolling;

S4 heat treatment: 300-500℃ for 5-8 hours;

S5 plastic surgery: use a straightening machine for shape correction;

S6 Machining: processing to the required size to obtain Ag-based alloy target blank;

S7 Binding: Bind the target embryo to the back plate, and that's it.

5. the preparation method of a kind of silver-scandium alloy sputtering target material according to claim 4, is characterized in that, in described S1, the method for described smelting is as follows:

Put the raw material into a carbonaceous crucible, place it in a high-frequency melting furnace, evacuate, the pressure is less than or equal to 1.3pa, and enter an Ar atmosphere of 1.5-8×10 ⁴ Pa, and the temperature gradually rises to 1400-1855 ℃, and maintains 20 -30min.

6 . The method for preparing a silver-scandium alloy sputtering target according to claim 5 , wherein, in the S1 , the melting temperature is gradually increased to 1800° C. and maintained for 25 minutes. 7 .

7. the preparation method of a kind of silver-scandium alloy sputtering target material according to claim 4, is characterized in that, in described S1, the method for described smelting is as follows:

Weigh the raw materials, put them into the crucible of the water-cooled crucible magnetic levitation melting furnace, vacuumize to -0.08MPa, fill with Ar gas until the pressure is 0, keep the pressure for 30s, and repeat the pumping and charging 3 times; turn on the high-frequency power supply, and gradually increase the heating power , starting from 2.0kw, increasing by 0.5kw every 1min, until there is a continuous flowing spherical molten metal in the crucible, increasing by 1kw every 0.5min, when it reaches 8kw, stop increasing the heating power, keep the temperature for 5min, let it cool, and take it out Rough ingot; put the rough ingot into the crucible again, repeat the above-mentioned smelting process 1-3 times;

In the last smelting, after the heat preservation is over, the smelted liquid is poured into the carbon casting mold while it is still hot.

8. the preparation method of silver-scandium alloy sputtering target material according to claim 4, is characterized in that, the step of described S3 rolling is as follows:

S3-1 Finishing hot rolling: three passes of finishing hot rolling, the rolling rate of each pass is 20-45%, the strain rate is 6-12%/s; the plate temperature after three passes of hot rolling is 500-700 °C;

S3-2 Water cooling: quenching from a temperature of 500-700°C at a cooling rate of 300°C/min;

S3-3 Cold rolling: at least one pass of cold rolling; the rolling ratio of each pass is 25-40%, and the average strain rate is 5-9%/s; cold rolling to the required plate thickness; cold rolling The final plate temperature was 150°C.

9 . The method for preparing a silver-scandium alloy sputtering target according to claim 4 , wherein in the S3 , ZrO ₂ wear-resistant ceramic rollers are used during the finishing hot rolling and the cold rolling. 10 .