Chromium target material, chromium film, mask plate and semiconductor preparation method

Abstract

The invention relates to the field of semiconductor manufacturing, in particular to a chromium target material, a chromium film, a mask plate and a preparation method of a semiconductor. The purity of the chromium target material is larger than or equal to 99.96%, the density is larger than or equal to 99.7%, the average grain size is smaller than or equal to 32 microns, the chromium target material is beneficial for preparing a thin film with good uniformity, light intensity distribution of exposure in the patterning process is more uniform, and therefore patterns with neat and smooth edges and high precision are obtained; it is ensured that the feature size and shape of the semiconductor device meet design requirements, the performance and reliability of the device are improved, and the production yield of the device is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing, and in particular to a method for preparing a chromium target, a chromium film, a mask, and a semiconductor. Background Art

[0002] Chromium targets, due to their excellent conductivity, corrosion resistance, and high stability, are ideal for producing high-quality metal films. This is particularly true in the semiconductor industry, where they are transformed into Cr thin films through sputtering, used to form the light-shielding layer of photomask substrates. As photomasks are critical components in semiconductor manufacturing, the patterns on them must be precise down to the nanometer level as semiconductor processes advance. Research has shown that even a single nanometer-scale speck of dust or pattern distortion can cause the entire chip to fail.

[0003] As the raw material for producing the chromium thin film used in the light-shielding layer of photomask substrates, the performance of chromium targets is crucial to the yield of photomask devices. In addition to purity, density and grain size are also key factors directly affecting the quality of chromium thin films on photomask devices. This is because high density reduces internal pores, improves sputtering efficiency, and ensures uniform thickness distribution of the sputtered film. Low-density chromium targets, on the other hand, have loose grains, which can easily lead to sputtering rate fluctuations and even discharge. High-density chromium targets also offer the advantage of high mechanical strength, which can withstand the high temperatures and thermal stresses of the sputtering process, reducing the risk of cracking. Low-density chromium targets, on the other hand, tend to adsorb gases, leading to the release of impurities during sputtering and causing blackening and poisoning of the target surface. Excessively large grain size can increase anisotropy during sputtering, increasing the differences in sputtering rates between different grains. This results in uneven film deposition, localized thickness fluctuations, or particle splashing, which in turn leads to a higher defect density in the chromium film.

[0004] However, the density of the chromium target material used in the prior art for preparing the light-shielding layer of the photomask substrate is only 99.5% at most, and the grain size is difficult to reach below 50 μm, which makes it difficult to meet the application requirements of nano-scale masks. Summary of the Invention

[0005] Based on this, the present application provides a chromium target material, which is conducive to the preparation of a thin film with good uniformity, and thus conducive to a more uniform distribution of the exposure light intensity, thereby obtaining a pattern with neat, smooth and high precision edges, ensuring that the characteristic size and shape of the semiconductor device meet the design requirements, improving the performance and reliability of the device, and improving the device production yield.

[0006] In a first aspect, the present application provides a chromium target material having a purity of ≥99.96%, a density of ≥99.7%, and an average grain size of ≤32 μm. This chromium target material has high purity, density, and extremely small grains, and has few internal pores, which can ensure uniform sputtering and the consistency of sputtered particle energy and direction, thereby reducing the defect density of the thin film and improving the yield of photomask devices. Furthermore, its density can reach above 99.8% and above 99.9%, and its average grain size can reach below 25 μm and below 20 μm.

[0007] High-purity chromium target materials can ensure that the sputtered chromium atoms or ions are pure and pollution-free, so that the composition of the formed chromium film is more uniform and stable. Low-purity chromium target materials may contain impurity elements, which may be brought into the film during the sputtering process, affecting the electrical or optical properties of the film. The purity of existing chromium target materials is generally at the 3N5 level (i.e., the purity is 99.95%). The purity of the chromium target material provided in this application can further reach 99.99% and above.

[0008] The chromium target material described above has an oxygen content of ≤70 ppm. In the prior art, the oxygen content of chromium targets used to prepare chromium thin films on masks is typically below 100 ppm. Studies have shown that reducing the oxygen content by 10 ppm can increase the mask yield by approximately 1.2%. The chromium target material provided in this application has an oxygen content of ≤70 ppm, which helps further improve the yield of mask devices. Furthermore, the oxygen content of this chromium target material is ≤40 ppm. The oxygen content of the chromium target material in this application is 30-70 ppm.

[0009] The total carbon, nitrogen, oxygen and sulfur content of the chromium target described above is ≤120 ppm. The lower carbon, nitrogen, oxygen and sulfur content is beneficial to further reduce the defect density of the film and improve the yield of the mask device. The total carbon, nitrogen, oxygen and sulfur content of the chromium target in this application is 80-110 ppm.

[0010] In the chromium target described above, the iron content is ≤70ppm. When the iron content in the chromium target is high, it will form an Fe-Cr solid solution with chromium. Local resistivity differences will lead to uneven current distribution on the target surface, thereby affecting the thickness uniformity of the film. By controlling the iron content to ≤70ppm, it is beneficial to further improve the film quality and thus improve the yield of the mask device. The iron content of the chromium target in this application is 60-70ppm.

[0011] According to the chromium target material described above, the surface roughness of the chromium target material is ≤1μm. The roughness of the chromium target surface will also directly affect the deposition process of the sputtered atoms or ions on the substrate. When the target surface is rough, the sputtered particles may have uneven energy and direction, resulting in uneven deposition on the substrate. This uneven deposition will increase the surface roughness of the film, affecting the optical, electrical and mechanical properties of the film. On the contrary, if the target surface is smooth, the energy and direction of the sputtered particles are more consistent, which is conducive to the formation of a film with a smooth surface. The lower the surface roughness, the more conducive it is to improving the uniformity of the prepared film, and thus to a more uniform distribution of the exposure light intensity during the patterning process. In the prior art, the surface roughness of the chromium target material used for magnetron sputtering to form a mask light-shielding layer is usually controlled to be below 1.5μm.

[0012] The chromium target material described above has a polycrystalline structure. The polycrystalline structure of the chromium target material makes its overall structure more stable due to the interaction between the grains. This stability helps to maintain the shape and size of the target material during the sputtering process, thereby ensuring that the sputtered chromium atoms or ions have stable energy and direction, which is further conducive to the formation of a uniform and dense film and improves the quality and performance of the film. Since the grain size and distribution in the polycrystalline structure are relatively uniform, it makes it easier to control the shape, size and purity of the target material during the preparation process. In addition, the polycrystalline structure of the chromium target material is also easier to maintain a stable sputtering rate and film quality during the sputtering process.

[0013] A second aspect of the present application provides a chromium film, which is prepared from the chromium target material described in the first aspect.

[0014] The chromium thin film described above is obtained by magnetron sputtering the chromium target material described in the first aspect.

[0015] A third aspect of the present application provides a device having at least a portion of its surface formed of the aforementioned chromium thin film. The device may be a thin-film transistor, an integrated circuit, a reflector, an optical filter, a flat-panel display, or an aerospace component (e.g., an aircraft engine component, wings, or fuselage).

[0016] The fourth aspect of the present application provides a mask, which includes a substrate and a chromium film stacked on one surface of the substrate, the chromium film is the chromium film described in the third aspect above, and the mask includes a blank mask or a mask with a preset pattern.

[0017] A fifth aspect of the present application provides a method for preparing a semiconductor device, comprising at least:

[0018] placing the mask with the preset pattern described in the fourth aspect above on the semiconductor substrate to be patterned;

[0019] After exposure, the preset pattern on the mask having the preset pattern is transferred to the semiconductor substrate to be patterned. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a metallographic image of the chromium target prepared in Example 1 of the present invention;

[0021] Figure 2 This is the metallographic diagram of a conventional chromium target;

[0022] Figure 3 This is the XRD pattern of the chromium target prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0024] Chromium targets, with their exceptional conductivity, superior corrosion resistance, and high stability, hold a pivotal position in materials science, particularly in the semiconductor industry. As the preferred material for producing high-quality metal films, chromium targets are transformed into dense Cr films through advanced technologies such as magnetron sputtering. This conversion process plays a crucial role in semiconductor device manufacturing. In particular, Cr films serve as light-shielding layers in the preparation of photomask substrates, and their quality directly impacts the precision and efficiency of subsequent patterning processes.

[0025] The internal quality of the chromium target material has a crucial influence on the performance of the resulting Cr thin film. Density is a key quality indicator for chromium targets. High-density targets have fewer internal pores and defects, which improve sputtering efficiency and ensure a uniform thickness distribution of the sputtered film. This, in turn, facilitates a more uniform distribution of light intensity during exposure, resulting in clean, smooth, and highly precise patterns. This ensures that the characteristic dimensions and shapes of semiconductor devices meet design requirements, improving device performance and reliability. Existing chromium targets have a maximum density of only 99.5%, and the coarse grains rarely reach below 50μm, making them difficult to meet the application requirements of nanoscale masks.

[0026] Based on this, the present application provides a chromium target material with a purity of ≥99.96%, a density of ≥99.7%, and an average grain size of ≤32μm. This chromium target material has few internal pores, which can improve sputtering efficiency and ensure a uniform thickness distribution of the sputtered film. The smaller and more uniform grain structure provides a more uniform sputtering rate, further ensuring the surface flatness of the film, thereby ensuring good film uniformity and facilitating a more uniform distribution of light intensity during exposure, thereby producing a pattern with neat, smooth edges and high precision, ensuring that the characteristic size and shape of the semiconductor device meet the design requirements, and improving the performance and reliability of the device.

[0027] In other specific embodiments of the present application, the purity of the chromium target is ≥99.99%, the oxygen content is ≤70 ppm, the total carbon, nitrogen, oxygen and sulfur content is ≤120 ppm, and the iron content is ≤70 ppm. This high-purity chromium target further ensures that the formed chromium film has a more uniform and stable composition.

[0028] When magnetron sputtering is used to form a chromium film, the roughness of the chromium target will also have an important impact on the performance of the formed film. When the surface roughness of the chromium target is high, there may be protrusions and depressions on its surface. During the sputtering process, these protrusions may be sputtered preferentially, resulting in uneven distribution of sputtered particles on the substrate. This uneven sputtering may cause the film to tend to be thicker in some areas and thinner in other areas, or even form voids or cracks, thereby reducing the density of the film. The lower the surface roughness, the more conducive it is to improving the uniformity of the prepared film, which in turn is conducive to a more uniform distribution of the exposure light intensity during the patterning process. In some specific embodiments of the present application, the surface roughness of the chromium target is ≤1μm, in other specific embodiments of the present application, the surface roughness of the chromium target is ≤0.5μm, in other specific embodiments of the present application, the surface roughness of the chromium target is ≤0.3μm, in other specific embodiments of the present application, the surface roughness of the chromium target is ≤0.15μm, and in other specific embodiments of the present application, the surface roughness of the chromium target is ≤0.1μm.

[0029] In some other specific embodiments of the present application, the chromium target material has a polycrystalline structure, which is easier to prepare and more conducive to forming a uniform and dense thin film.

[0030] It should be noted that the metal impurity content in the present invention is obtained based on the full element content analysis obtained by GDMS testing. In the present invention, a purity of 99.99% means that the purity has reached the 4N level, and a purity of 99.995% means that the purity has reached the 4N5 level. A purity of 4N (i.e., 99.99%) means that after GDMS full element analysis, the sum of the contents of the remaining elements (except chromium) is less than 100ppm, except for C, N, O, S, and H. 4N2 (i.e., 99.992%) means that after GDMS full element analysis, the sum of the contents of the remaining elements (except chromium) is less than 80ppm, except for C, N, O, S, and H. 3N8 (i.e., 99.98%) means that after GDMS full element analysis, the sum of the contents of the remaining elements (except chromium) is less than 120ppm, except for C, N, O, S, and H. 3N6 (i.e., 99.96%) means that after GDMS full elemental analysis, the sum of the contents of all elements (excluding chromium) other than C, N, O, S, and H is less than 140 ppm. 3N7 (i.e., 99.97%) means that after GDMS full elemental analysis, the sum of the contents of all elements (excluding chromium) other than C, N, O, S, and H is less than 130 ppm.

[0031] The present application also provides a method for preparing the above-mentioned chromium target, which at least includes a process of sintering raw chromium powder into a chromium target through a hot isostatic pressing process; wherein the raw chromium powder includes a first chromium powder and a second chromium powder, the mass ratio of the first chromium powder to the second chromium powder is (2-3):1, the first chromium powder meets the following requirements: purity ≥99.95%, sphericity ≥0.9, and particle size D50 ≤300μm; the second chromium powder meets the following requirements: purity ≥99.95%, sphericity ≥0.9, and particle size D50 ≤100μm; the hot isostatic pressing process parameters meet the following requirements: hot isostatic pressing temperature 1100-1200℃, heating rate 5-10℃ / min, and hot isostatic pressing pressure 120-180MPa.

[0032] The preparation method provided in the present application can be achieved by selecting specific chromium powder as raw material and undergoing a one-step hot isostatic pressing process. The preparation method is simple and easy to implement.

[0033] It is understandable that the purity of the chromium target also has a significant impact on the performance of the formed film. A high-purity chromium target can ensure that the purity of the chromium atoms deposited on the substrate during the sputtering process is high, reducing the introduction of impurity atoms, thereby improving the purity of the chromium film and improving its electrical, optical and mechanical properties. If the chromium target contains a large amount of impurities, these impurities may be sputtered out during the sputtering process and deposited on the film, resulting in a decrease in film performance and even defects. For example, chromium targets with high oxygen content are prone to forming oxides during the sputtering process. The sputtering rate of these oxides is usually lower than that of pure metal chromium targets. This is because the bond energy of these oxides is high, resulting in a decrease in energy transfer efficiency during the sputtering process. Therefore, chromium targets with high oxygen content will reduce the sputtering rate, thereby affecting the deposition speed and thickness of the film, resulting in local fluctuations in the film thickness during the sputtering process, affecting the overall uniformity of the film. In addition, the presence of oxides may also cause microscopic defects such as holes and cracks to form in the film, thereby affecting the film performance.

[0034] Therefore, during the specific preparation, taking into account issues such as the purity of the chromium target material obtained later, the chromium powder used preferably meets the following conditions: purity ≥99.99%. Under this condition, the quality of the chromium target material obtained can be further improved. The chromium powder can be prepared from a chromium raw material with a purity ≥99.99% (such as electrolytic chromium sheet) through a crucible-free smelting gas atomization process. Furthermore, in order to ensure its purity, the chromium ingot prepared by the suspension smelting process can be subjected to a crucible-free smelting gas atomization treatment after removing a surface layer of ≥5mm. The parameters of the crucible-free smelting gas atomization process can be set as follows: the melting rate of the chromium raw material is 2-4 drops / second, and the gas ejection rate is 500-600m / s.

[0035] The oxygen content can be further controlled to be ≤70ppm, the total carbon, nitrogen, oxygen and sulfur content can be further controlled to be ≤120ppm, and the iron content can be further controlled to be ≤70ppm. Controlling the raw materials is conducive to preparing chromium targets with relatively low impurity content.

[0036] In the above preparation method, the temperature of the hot isostatic pressing process is 1100-1200°C, for example, it can be 1100°C, 1110°C, 1120°C, 1130°C, 1140°C, 1150°C, 1160°C, 1170°C, 1180°C, 1190°C, 1200°C and the range between any two of the above values.

[0037] The heating rate is 5-10°C / min, for example, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min and the range between any two of the above values.

[0038] The hot isostatic pressing pressure is 120-180 MPa, for example, it can be 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa and a range between any two of the above values.

[0039] The holding time depends on the size of the workpiece, generally 2-4 hours, for example, it can be 2 hours, 2.3 hours, 3 hours, 3.5 hours, 4 hours.

[0040] The vacuum bag used in this application is subject to specific restrictions, as long as it can meet the requirements of preventing air leakage and melting during the hot isostatic pressing process. In some specific embodiments of this application, the vacuum bag used is a corrosion-resistant metal bag, which is welded and formed from a material with a thickness of 1.0-5.0 mm and has a degassing tube extending therefrom.

[0041] In actual operation, chromium powder is added into the vacuum bag, the degassing tube is connected to the vacuum equipment, and then the vacuum bag is sealed and vacuum is started at room temperature. When the vacuum degree in the vacuum bag reaches a certain level, for example, the vacuum degree in the vacuum bag is 2×10 -3 Pa, start heating the vacuum bag (generally heated to 250-500℃) and continue to evacuate (keep the vacuum degree in the vacuum bag less than or equal to 2×10 -3 Pa), keep warm for 3-4h, and then seal the vacuum bag to form a closed vacuum environment in the vacuum bag. At this time, the vacuum degree in the vacuum bag is ≥2×10 -3 Pa. The vacuum envelope is then placed in a hot isostatic pressing furnace and sintered to form the chromium powder. After sintering, the furnace temperature is lowered to below 200°C and the pressure is gradually released. The furnace door is opened and the vacuum envelope is removed. The vacuum envelope is physically dismantled, and the surface layer (≥15 mm) is removed before slicing to obtain the chromium target.

[0042] Furthermore, in order to obtain a chromium target with low surface roughness, the chromium target may be polished to reduce its surface roughness to ≤ 1 μm. The target may be subjected to rough grinding and fine grinding before polishing.

[0043] In detail, rough grinding is to use coarser sandpaper (such as 120 mesh) to remove surface burrs and obvious scratches. After rough grinding, the surface roughness is improved, but there are still obvious scratches, usually in the range of Ra 2.5 to 0.63μm. Fine grinding is to use finer sandpaper (such as 800 mesh, 1200 mesh) for fine grinding until there are no obvious scratches on the surface. After fine grinding, the surface quality is significantly improved, and the roughness is close to the final requirement, usually in the range of Ra 0.63 to 0.16μm. Polishing is to use a polishing machine and polishing paste to remove the fine scratches generated during the grinding process, and finally achieve an extremely high surface finish. After polishing, the surface roughness can be as low as Ra 0.01μm.

[0044] The present application also provides a chromium film, which is prepared from the above-mentioned chromium target material.

[0045] Since the chromium target material described above in this application is used as the raw material, the thickness distribution of the prepared chromium film is uniform and the film flatness is good, which is conducive to more uniform distribution of exposure light intensity during the patterning process, and is conducive to obtaining patterns with neat, smooth and high precision edges, ensuring that the characteristic size and shape of the semiconductor device meet the design requirements, improving the performance and reliability of the device, and improving the device production yield.

[0046] In some specific embodiments of the present application, the chromium target can be prepared by physical vapor deposition technology to obtain a chromium thin film.

[0047] Physical vapor deposition techniques include magnetron sputtering, vacuum evaporation, and ion plating. Magnetron sputtering, as a highly efficient physical vapor deposition (PVD) method, utilizes a special distribution of orthogonal electromagnetic fields to control the trajectory of electrons in an electric field, causing them to exhibit cycloidal motion, thereby significantly increasing the probability of collision with gas molecules and enabling high-speed sputtering and deposition. It is currently the most widely used method for preparing chromium thin films in the semiconductor field. In some embodiments of the present application, magnetron sputtering is performed using the chromium target material described above in the present application in a protective atmosphere, causing the chromium to separate from the target and deposit onto a substrate to form a chromium thin film.

[0048] The present application also provides a device having at least a portion of its surface formed of the aforementioned chromium thin film. The device may be a thin-film transistor, an integrated circuit, a reflector, an optical filter, a flat-panel display, or an aerospace component (such as an aircraft engine component, wings, or fuselage).

[0049] The present application also provides a mask, which includes a substrate and a chromium film stacked on a surface of one side of the substrate, and the chromium film is the aforementioned chromium film.

[0050] In some specific embodiments of the present application, the substrate may be, but is not limited to, transparent glass, such as quartz glass or soda glass, and the chromium thin film may have a single-layer structure or a stacked structure of two or more layers.

[0051] In some specific embodiments of the present application, the reticle includes a blank reticle and a reticle with a preset pattern. The blank reticle is a reticle without a preset pattern. The chromium film in the preset area of ​​the blank reticle is removed to obtain a chromium film with the preset pattern.

[0052] Since the light-shielding chromium film on the mask is prepared from the chromium target material and chromium film provided in this application, its thickness is uniform, which can ensure a more uniform distribution of the exposure light intensity during the patterning process, thereby obtaining a pattern with neat, smooth and high precision edges, which is beneficial to improving the performance and reliability of the device and increasing the production yield of the device.

[0053] The present application also provides a method for preparing a semiconductor device, comprising placing the mask with a preset pattern provided above in the present application on a semiconductor substrate to be patterned, and transferring the pattern on the mask to the semiconductor substrate to be patterned after exposure and development, so that a patterned semiconductor substrate can be finally prepared.

[0054] The semiconductor device may be, for example but not limited to, a chip. During the chip preparation process, other functional layers may be prepared after the patterning process is completed.

[0055] In some specific embodiments of the present application, the semiconductor device can be used in terminal devices, such as mobile phones, tablet computers, laptop computers, digital cameras, wearable electronic devices, virtual reality devices, etc.

[0056] The chromium target material and its preparation method described in this application are described in detail below with reference to specific embodiments.

[0057] In the following embodiments, the purity of the chromium powder and the chromium target is tested by high-resolution glow discharge mass spectrometry (HR-GDMS). Through GDMS testing, the content of all elements can be obtained, and thus the purity can be obtained.

[0058] The oxygen impurity content was tested using the vacuum melting-inert gas melting method.

[0059] Carbon and sulfur impurities are tested by sulfur-carbon analyzer;

[0060] Nitrogen content was measured by EGA evolved gas analysis method;

[0061] The particle size D50 and sphericity of the chromium powder are directly measured by a laser particle size analyzer.

[0062] The density of the chromium target was tested by the drainage method and the measured density was compared with the standard density (7.19 g / cm 3 ) is the density.

[0063] The grain size of the chromium target was measured using a metallographic microscope.

[0064] The roughness of the chromium target is measured using a roughness meter.

[0065] The crystal phase composition of the chromium target was obtained by XRD analysis.

[0066] Example 1

[0067] This embodiment provides a chromium target, which is prepared by the following method: the performance indicators of the raw material chromium powder used are shown in Tables 1 and 2 below.

[0068] Table 1 Performance indicators of the first chromium powder

[0069] index O Fe Particle size D50 purity Sphericity Total content of carbon, nitrogen, oxygen and sulfur Numerical 30ppm 56ppm 238μm 4N 0.93 83ppm

[0070] Table 2 Performance indicators of the second chromium powder

[0071] index O Fe Particle size D50 purity Sphericity Total content of carbon, nitrogen, oxygen and sulfur Numerical 37ppm 59ppm 77μm 4N2 0.97 81ppm

[0072] The first chromium powder and the second chromium powder were mixed in a mass ratio of 2:1 and added into the vacuum bag. The vacuum bag was then sealed and vacuumed at room temperature. When the vacuum degree in the bag reached 2×10 -3 Pa, start heating the vacuum bag and continue to evacuate the bag to keep the vacuum degree not less than 2×10 -3 Pa, when the temperature reaches 450 ° C, stop heating and keep warm for 4 hours, and then seal the vacuum bag. After that, place the vacuum bag in a hot isostatic pressing furnace, raise the temperature to 1200 ° C at a heating rate of 10 ° C / min, and use inert gas argon as a medium to provide an isotropic pressure of 140 MPa, keep warm and maintain pressure for 3 hours, and sinter. After sintering, reduce the furnace temperature in the hot isostatic pressing furnace to below 200 ° C and gradually release the pressure. Open the furnace door and take out the vacuum bag. Remove the vacuum bag to obtain the chromium ingot. After cutting off the surface layer of 15 mm on the surface of the chromium ingot, slice it to remove the burrs, remove the burrs, and obtain the chromium target after rough grinding, fine grinding and polishing.

[0073] The chromium target prepared above was tested, and the metallographic test results were as follows: Figure 1 As shown, the metallographic structure of conventional chromium target is as follows: Figure 2 As shown. Figure 1 、 2 It can be seen that the grain size of the chromium target material in this embodiment is 18.9 μm, while the grain size of the conventional chromium target material is 237 μm. The XRD pattern of the chromium target material prepared in this embodiment is shown in FIG. Figure 3 As shown by Figure 3 It can be seen that the chromium target material has a polycrystalline structure. The performance results of the chromium target material prepared in this embodiment are shown in Table 3 below:

[0074] Table 3

[0075] element Chromium target Fe 60ppm Total metal impurities content 89ppm C 26ppm O 35ppm Total content of carbon, nitrogen, oxygen and sulfur 89ppm purity 4N grains 18.9μm density 99.8％ surface roughness 0.08μm

[0076] Example 2

[0077] This embodiment provides a chromium target, which is prepared by the following method. The performance indicators of the raw chromium powder used are the same as those in Example 1, except that the mass ratio of the first chromium powder to the second chromium powder is 3:1.

[0078] The first chromium powder and the second chromium powder were mixed in a mass ratio of 3:1 and added into the vacuum bag. The vacuum bag was then sealed and vacuumed at room temperature. When the vacuum degree in the bag reached 2×10 -3 Pa, start heating the vacuum bag and continue to evacuate the bag to keep the vacuum degree not less than 2×10 -3 Pa, when the temperature reaches 450 ° C, stop heating and keep warm for 4 hours, and then seal the vacuum bag. After that, place the vacuum bag in a hot isostatic pressing furnace, raise the temperature to 1150 ° C at a heating rate of 8 ° C / min, and use inert gas argon as a medium to provide an isotropic pressure of 170 MPa, keep warm and keep pressure for 2 hours, and sinter. After sintering, reduce the furnace temperature in the hot isostatic pressing furnace to below 200 ° C and gradually release the pressure. Open the furnace door and take out the vacuum bag. Remove the vacuum bag to obtain the chromium ingot. After cutting off the surface layer of 15 mm on the surface of the chromium ingot, slice it to remove the burrs, and then grind it into a chromium target through rough grinding and fine grinding.

[0079] The chromium target prepared above was tested, and the results are shown in Table 4 below:

[0080] Table 4

[0081] element Chromium target Fe 62ppm Total metal impurities content 91ppm C 25ppm O 33ppm Total content of carbon, nitrogen, oxygen and sulfur 89ppm purity 4N grains 31.3μm density 99.9％ surface roughness 0.87μm

[0082] Example 3

[0083] This embodiment provides a chromium target material, which is prepared by the following method. The performance indicators of the raw material chromium powder used are shown in Tables 5 and 6 below:

[0084] Table 5 Performance indicators of the first chromium powder

[0085] index O Fe Particle size D50 purity Sphericity Total content of carbon, nitrogen, oxygen and sulfur Numerical 65ppm 89ppm 129μm 3N8 0.93 117ppm

[0086] Table 6 Performance indicators of the second chromium powder

[0087] index O Fe Particle size D50 Aggregation purity Sphericity Total content of carbon, nitrogen, oxygen and sulfur Numerical 37ppm 59ppm 77μm 1.1 4N2 0.97 81ppm

[0088] The first chromium powder and the second chromium powder were mixed in a mass ratio of 2:1 and added into the vacuum bag. The vacuum bag was then sealed and vacuumed at room temperature. When the vacuum degree in the bag reached 2×10 -3 Pa, start heating the vacuum bag and continue to evacuate the bag to keep the vacuum degree not less than 2×10 -3Pa, when the temperature reaches 450 ° C, stop heating and keep warm for 4 hours, and then seal the vacuum bag. After that, place the vacuum bag in a hot isostatic pressing furnace, raise the temperature to 1100 ° C at a heating rate of 5 ° C / min, and use inert gas argon as a medium to provide an isotropic pressure of 140 MPa, keep warm and maintain pressure for 4 hours, and sinter. After sintering, reduce the furnace temperature in the hot isostatic pressing furnace to below 200 ° C and gradually release the pressure. Open the furnace door and take out the vacuum bag. Remove the vacuum bag to obtain the chromium ingot. After cutting off the surface layer of 15 mm on the surface of the chromium ingot, slice it to remove the burrs, and then obtain the chromium target after rough grinding, fine grinding and polishing.

[0089] The chromium target prepared above was tested, and the results are shown in Table 7 below:

[0090] Table 7

[0091]

[0092]

[0093] Comparative Example 1

[0094] The difference between this comparative example and Example 1 is that the raw materials of chromium powder used are different. The performance indicators of the raw material chromium powder used in this comparative example are shown in Table 8 below:

[0095] Table 8

[0096] index O Fe Particle size D50 purity Sphericity Total content of carbon, nitrogen, oxygen and sulfur Numerical 99ppm 84ppm 342μm 3N8 0.89 185ppm

[0097] The raw material chromium powder was added into the vacuum bag, and then the vacuum bag was sealed and vacuum was started at room temperature. When the vacuum degree in the bag reached 2×10 -3 Pa, start heating the vacuum bag and continue to evacuate the bag to keep the vacuum degree not less than 2×10 -3 Pa, when the temperature reaches 450 ° C, stop heating and keep warm for 4 hours, and then seal the vacuum bag. After that, place the vacuum bag in a hot isostatic pressing furnace, raise the temperature to 1200 ° C at a heating rate of 10 ° C / min, and use inert gas argon as a medium to provide an isotropic pressure of 140 MPa, keep warm and maintain pressure for 3 hours, and sinter. After sintering, reduce the furnace temperature in the hot isostatic pressing furnace to below 200 ° C and gradually release the pressure. Open the furnace door and take out the vacuum bag. Remove the vacuum bag to obtain the chromium ingot. After cutting off the surface layer of 15 mm on the surface of the chromium ingot, slice it to remove the burrs, and then obtain the chromium target after rough grinding, fine grinding and polishing.

[0098] The chromium target prepared above was tested, and the results are shown in Table 9 below:

[0099] Table 9

[0100] element Chromium target Fe 81ppm Total metal impurities content 124ppm C 59ppm O 101ppm Total content of carbon, nitrogen, oxygen and sulfur 192ppm purity 3N7 grains 76.4μm density 99.7％ surface roughness 0.11μm

[0101] Comparative Examples 2-3

[0102] Comparative Example 2-3 uses the same chromium powder as Example 1. The difference from Example 1 is that the heating rates in the hot isostatic pressing process parameters are 3°C / min and 12°C / min, respectively. The preparation method of the chromium target includes the following steps:

[0103] The raw material chromium powder was added into the vacuum bag, and then the vacuum bag was sealed and vacuum was started at room temperature. When the vacuum degree in the bag reached 2×10 -3 Pa, start heating the vacuum bag and continue to evacuate the bag to keep the vacuum degree not less than 2×10 -3 Pa, when the temperature reaches 450 ° C, stop heating and keep warm for 4 hours, and then seal the vacuum bag. After that, place the vacuum bag in a hot isostatic pressing furnace, raise the temperature to 1200 ° C at the above-set heating rate, and use inert gas argon as a medium to provide an isotropic pressure of 100 MPa, keep warm and maintain pressure for 5 hours, and sinter. After sintering, reduce the furnace temperature in the hot isostatic pressing furnace to below 200 ° C and gradually release the pressure. Open the furnace door and take out the vacuum bag. Remove the vacuum bag to obtain the chromium ingot. After cutting off the surface layer of 15 mm on the surface of the chromium ingot, slice it to remove burrs, remove burrs, and obtain the chromium target after rough grinding, fine grinding and polishing.

[0104] The chromium target prepared above was tested, and the results are shown in Table 10 below:

[0105] Table 10

[0106]

[0107] Comparative Example 4

[0108] Comparative Example 4 uses the same chromium powder as Example 1. The difference from Example 1 is that the hot isostatic pressing process parameters are: inert gas argon is used as the medium to provide an isotropic pressure of 110 MPa. The preparation method of the chromium target includes the following steps:

[0109] The raw material chromium powder was added into the vacuum bag, and then the vacuum bag was sealed and vacuum was started at room temperature. When the vacuum degree in the bag reached 2×10 -3 Pa, start heating the vacuum bag and continue to evacuate the bag to keep the vacuum degree not less than 2×10 -3Pa, when the temperature reaches 450 ° C, stop heating and keep warm for 4 hours, and then seal the vacuum bag. After that, place the vacuum bag in a hot isostatic pressing furnace, raise the temperature to 1200 ° C at a heating rate of 10 ° C / min, and use inert gas argon as a medium to provide isotropic pressure to 110 MPa, keep warm and maintain pressure for 5 hours, and sinter. After sintering, reduce the furnace temperature in the hot isostatic pressing furnace to below 200 ° C and gradually release the pressure. Open the furnace door and take out the vacuum bag. Remove the vacuum bag to obtain the chromium ingot. After cutting off the surface layer of 15 mm on the surface of the chromium ingot, slice it and deburr it. After rough grinding, fine grinding and polishing, the chromium target is obtained.

[0110] The chromium target prepared above was tested, and the results are shown in Table 11 below:

[0111] Table 11

[0112]

[0113]

[0114] The chromium targets obtained in Example 1 and Comparative Example 2 were subjected to magnetron sputtering coating using the same process parameters on a test machine (not a mass production machine). The substrate material was an 8-inch silicon wafer. Multiple tests were performed under different process conditions. It was found that the number of small particles produced on the chromium film formed by the chromium target in Comparative Example 2 was 2-7 times that of the chromium target in Example 1.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A chromium target, characterized in that: The purity of the chromium target material is ≥99.96%, the density is ≥99.7%, and the average grain size is ≤32 μm.

2. The chromium target according to claim 1, characterized in that The purity of the chromium target material is ≥99.99%.

3. The chromium target according to claim 1 or 2, characterized in that The oxygen content in the chromium target is ≤70ppm, and / or Total carbon, nitrogen, oxygen and sulfur content ≤ 120ppm; and / or Iron content ≤70ppm.

4. The chromium target according to any one of claims 1 to 3, characterized in that The surface roughness of the chromium target is ≤1 μm.

5. The chromium target according to any one of claims 1 to 4, characterized in that: The chromium target material has a polycrystalline structure.

6. A chromium thin film, characterized in that: The chromium target is prepared from the chromium target according to any one of claims 1 to 5.

7. The chromium thin film according to claim 6, characterized in that The chromium target material is obtained by magnetron sputtering.

8. A device, characterized in that At least a portion of the surface of the device is the chromium thin film according to claim 6 or 7.

9. A mask, characterized in that: It comprises a substrate and a chromium film stacked on one surface of the substrate, wherein the chromium film is the chromium film according to claim 6 or 7, and the mask comprises a blank mask or a mask with a preset pattern.

10. A method for preparing a semiconductor device, characterized in that: At least: placing the mask having the preset pattern as claimed in claim 9 on the semiconductor substrate to be patterned; After exposure, the preset pattern on the mask having the preset pattern is transferred to the semiconductor substrate to be patterned.

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