A highly reflective and highly conductive multi-component alloy electrode film and its preparation method and application

Abstract

The present invention belongs to the technical field of novel electronic device preparation, and discloses a highly reflective and highly conductive multi-component alloy electrode film, as well as a preparation method and application thereof. The alloy electrode film is a copper-based alloy, and its components are: Cu-Cr-Zr-Ag, the content of Cu element is 99wt%-99.8wt%, the content of Cr element is 0.12wt%-0.3wt%, the content of Zr element is 0.05wt%-0.2wt%, and the content of Ag element is 0.1wt%-0.2wt%. The present invention retains the characteristics of high bonding strength and preventing the diffusion of deterioration by introducing silver element. At the same time, the addition of silver optimizes the electrical conductivity of the electrode, and at the same time, it also plays a modifying role in the surface morphology of the film, reduces the surface roughness, and improves the reflectivity of the film. At the same time, the present invention adopts a dual-target magnetron co-sputtering method to deposit the film, and the composition of each component in the film can be freely regulated by changing the power.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic device preparation, and in particular relates to a high-reflection and high-conductivity multi-component alloy electrode film and a preparation method and application thereof. Background Art

[0002] In recent years, display panels have been developing towards large size, high resolution, high refresh rate and flexibility. The increase in the overall size of the panel and the reduction in the unit pixel area have led to an increase in the length of the interconnect lines of the thin film transistor array as the display driver circuit, a decrease in line width and spacing, and a continuous increase in resistance and capacitance, which ultimately leads to an increase in circuit RC delay. Traditional conductive electrode materials represented by aluminum have been unable to meet the requirements of high-performance flexible display devices due to their high resistivity and weak resistance to electromigration. Compared with traditional aluminum interconnect electrode materials, copper has the following advantages when used in high-performance thin film transistor devices: (1) good conductivity, which is conducive to reducing line width, increasing pixel aperture ratio, and reducing device power consumption; (2) strong resistance to electromigration, which is conducive to increasing current density; (3) good thermal conductivity, which is conducive to device heat dissipation, and is particularly suitable for new current-driven OLED display panels.

[0003] However, Cu metal films have poor adhesion and Cu atoms are prone to degradation and diffusion at the interface. At the same time, since pure copper films are prone to defects and accumulate during flexible bending, their resistivity increases during bending, making it impossible to realize their full potential in flexible display devices. In response to the above problems, some relevant technical solutions in this regard have been proposed in existing patents. After searching, the Chinese patent number CN201710582067.4 proposed a Cu-Cr-Zr ternary copper alloy doping scheme doped with Cr and Zr elements. The Cr and Zr elements diffuse into the surface of the film to form a self-passivation layer, thereby overcoming the shortcomings of diffusion and low bonding strength. However, at the same time, the granular morphology of the passivation layer surface will lead to a higher film roughness, resulting in poor contact with the various functional layers in the device and a larger scattering effect in the visible band, which reduces the reflectivity. At the same time, the lattice distortion caused by Cr and Zr reduces the flexible conductive performance of the electrode. Summary of the Invention

[0004] In order to overcome the defects and shortcomings of the prior art, the primary purpose of the present invention is to provide a highly reflective and highly conductive multi-component alloy electrode film.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned highly reflective and highly conductive multi-component alloy electrode film, which adopts the technology of trace multi-component doping high-conductivity Cu alloy electrode material: based on the principle of "ultra-low solid solubility trace alloy doping", PVD low-temperature dual-target co-sputtering is used to dope Ag element, and Ag element is self-assembled on the surface of the film to form a "fishing net" structure, which prevents the diffusion and enrichment of Cr and Zr elements to produce particles, thereby optimizing the surface of the film. Ag element can also promote the growth of the {111} crystal plane family, so that the close-packed plane of the film grows preferentially, thereby improving the conductive properties and flexible electrical properties of the film.

[0006] Another object of the present invention is to provide applications of the above-mentioned highly reflective and highly conductive multi-component alloy electrode film.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A highly reflective and highly conductive multi-component alloy electrode film, wherein the alloy electrode film is a copper-based alloy having the following composition: Cu-Cr-Zr-Ag, wherein the content of the Cu element is 99wt%-99.8wt%, the content of the Cr element is 0.12wt%-0.3wt%, the content of the Zr element is 0.05wt%-0.2wt%, and the content of the Ag element is 0.1wt%-0.2wt%.

[0009] Preferably, the film has a thickness of 80 nm to 120 nm, a reflectivity of ≥60%, and a resistivity of ≤3 μΩ·cm.

[0010] The method for preparing the highly reflective and highly conductive multi-component alloy electrode film comprises the following steps:

[0011] (1) Cleaning the coating substrate and polishing the sputtering surface of the alloy target;

[0012] (2) Fixing the substrate and target material in corresponding positions, setting the pulsed DC sputtering mode, selecting the dual-target magnetron co-sputtering process, and sputtering the alloy target material onto the substrate to obtain a thin film during the thin film deposition process;

[0013] (3) The film obtained in step (2) is subjected to atmosphere annealing to finally obtain a Cu-Cr-Zr-Ag multi-component alloy electrode film.

[0014] Preferably, the alloy target material in step (1) includes alloy target material 1 and alloy target material 2, alloy target material 1 is a Cu-Cr-Zr ternary alloy target material, wherein the mass ratio of the Cr element is 0.12%-0.3%, and the mass ratio of the Zr element is 0.08%-0.2%, and alloy target material 2 is a Cu-Ag binary alloy target material, wherein the mass ratio of the Ag element is 0.1%-0.2%.

[0015] Preferably, the parameters of the dual-target magnetron co-sputtering process in step (2) are: duty cycle of 30%-60%, sputtering period of 20-50 μs, distance from target to substrate of 10-20 cm, sputtering pressure of 0.1 mTorr-0.3 mTorr, sputtering power of 40 W-120 W, and argon flow rate of 20 sccm-30 sccm.

[0016] Preferably, the sputtering power of target 1 is 100-120W, and the sputtering power of target 2 is 40-70W.

[0017] Preferably, the annealing atmosphere in step (3) is a nitrogen atmosphere, the pressure is controlled to be 600mToor-700mToor, the nitrogen flow rate is controlled to be 10sccm-15sccm, and the annealing time in the atmosphere is 30 to 60 minutes.

[0018] Preferably, the polishing in step (1) is performed using sandpaper with a mesh size of 200-2000.

[0019] Preferably, the substrate in step (1) is one of a PI substrate, a PEN substrate, a PE substrate, a PET substrate, and a CPI substrate, and the thickness of the substrate is 0.7 mm to 1 mm.

[0020] Preferably, the annealing in step (3) is RTA rapid annealing treatment, with a heating rate of 30°C / s-50°C / s and a cooling rate of 2°C / min-3°C / min.

[0021] Application of the above-mentioned highly reflective and highly conductive multi-component alloy electrode film in flexible wearable devices.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] (1) The high-reflectivity and high-conductivity multi-component alloy electrode film of the present invention reduces lattice distortion in the film by doping with silver, while promoting the preferential growth of the {111} crystal plane family. The {111} crystal plane family is the most closely packed plane in copper crystals, with the largest interplanar spacing and the lowest interplanar energy. It can effectively reduce the influence of external defects during dynamic bending, thereby improving the conductivity and flexible stability of the electrode.

[0024] (2) The high-reflection and high-conductivity multi-component alloy electrode film of the present invention blocks the aggregation and growth of Cr and Zr elements through the fishnet structure formed by the silver element in the supersaturated solid solution zone, effectively reduces the surface roughness of the film, and optimizes the contact characteristics in the device.

[0025] (3) The multi-component alloy electrode film of the present invention optimizes surface morphology, reduces light scattering, and possesses high reflectivity. It can be widely used in highly reflective electronic devices. The electrode film can achieve a reflectivity of over 60% across the entire visible light band. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the conductivity of the highly reflective and highly conductive multi-component alloy electrode film on the glass substrate.

[0027] Figure 2 It is the conductivity of the highly reflective and highly conductive multi-component alloy electrode film on the PI substrate.

[0028] Figure 3 This is the 3D result of AFM test of highly reflective and highly conductive multi-component alloy electrode film.

[0029] Figure 4 It is the reflectivity of the highly reflective and highly conductive multi-component alloy electrode film in the visible light band of 370nm-700nm.

[0030] Figure 5 This test is to test the bonding strength of highly reflective and highly conductive multi-component alloy electrode films on glass substrates.

[0031] Figure 6 This test is to test the bonding strength of highly reflective and highly conductive multi-component alloy electrode films on PI substrates. DETAILED DESCRIPTION

[0032] The present invention will be described in further detail below with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

[0033] In the examples of the present invention, if the specific conditions are not specified, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. All raw materials and reagents used without specifying the manufacturer are conventional products that can be purchased from the market.

[0034] Target 1 was purchased from Zhongnuo New Materials (Beijing) Technology Co., Ltd.

[0035] Target 2 was purchased from Zhongnuo New Materials (Beijing) Technology Co., Ltd.

[0036] Example 1

[0037] The specific steps of a highly reflective and highly conductive multi-component alloy electrode film for flexible display in this embodiment are as follows:

[0038] (1) Cleaning the flexible substrate: First, a 10 × 10 mm PI substrate was exposed to UV light for 120 seconds to decompose any organic contaminants on the surface. After cleaning, the substrate was ultrasonically cleaned twice with deionized water for 15 minutes each time to remove water-soluble contaminants. The substrate was then ultrasonically cleaned with isopropyl alcohol for 15 minutes to remove any remaining contaminants and moisture. The substrate was placed in a constant temperature drying oven at 80°C for at least 2 hours to obtain a clean and dry substrate.

[0039] (2) Target polishing: Target 1 is Cu-0.12wt%Cr-0.08wt%Zr and target 2 is Cu-0.1wt%Ag alloy target. The sputtering surfaces of the targets are polished using 200-mesh, 800-mesh, and 2000-mesh sandpaper, respectively.

[0040] (3) DC magnetron sputtering of a copper alloy thin film was performed. First, the gas pressure was controlled to 0.2 mToor and the argon flow rate was controlled to 25 sccm, and a pre-sputtering treatment was performed for 100 s. After the pre-sputtering, the sputtering power of target 1 was controlled to 100 W, and the sputtering power of target 2 was controlled to 40 W. Pulsed DC magnetron sputtering was performed for 600 s to finally obtain a CCZA alloy thin film.

[0041] (4) High-temperature annealing in nitrogen atmosphere: The film was placed in an RTA rapid annealing heat treatment furnace and nitrogen was introduced to maintain the pressure at 600 mTorr. The temperature was raised from room temperature to 300°C at a rate of 30°C / s and then maintained for 30 min. The temperature was then naturally cooled to 100°C and the copper alloy film was removed to obtain a Cu-Cr-Zr-Ag multi-component alloy electrode film.

[0042] (5) The film was subjected to four-probe testing, AFM testing, tape testing, and XRF testing. The copper alloy film was found to have a silver content of 0.1 wt%, good electrical conductivity, a resistivity of 2.95 μΩ.cm (PI-400°C), a surface roughness as low as 1.86 nm, a reflectivity of over 60%, and a bonding strength of 4B.

[0043] Example 2

[0044] (1) Cleaning the flexible substrate: First, a 10 × 10 mm glass substrate was exposed to UV light for 120 seconds to decompose any organic contaminants on the surface. After cleaning, the substrate was ultrasonically cleaned twice with deionized water for 15 minutes each time to remove water-soluble contaminants. The substrate was then ultrasonically cleaned with isopropyl alcohol for 15 minutes to remove any remaining contaminants and moisture. The substrate was placed in a constant temperature drying oven at 80°C for at least 2 hours to obtain a clean and dry substrate.

[0045] (2) Target polishing: Target 1 is Cu-0.12wt%Cr-0.08wt%Zr and target 2 is Cu-0.1wt%Ag alloy target. The sputtering surfaces of the targets are polished using 200-mesh, 800-mesh, and 2000-mesh sandpaper, respectively.

[0046] (3) Pulsed DC magnetron sputtering of a copper alloy film was performed. First, the gas pressure was controlled to 0.2 mToor and the argon flow rate was controlled to 25 sccm, and a pre-sputtering treatment was performed for 100 s. After the pre-sputtering, the sputtering power of target 1 was controlled to 100 W and the sputtering power of target 2 was controlled to 50 W. Pulsed DC magnetron sputtering was performed for 600 s to finally obtain a CCZA alloy film.

[0047] (4) Nitrogen atmosphere high-temperature annealing: The film was placed in an RTA rapid annealing heat treatment furnace and nitrogen was introduced to maintain the pressure at 600 mTorr. The temperature was raised from room temperature to 400°C at a rate of 30°C / s and then maintained for 30 min. The film was then naturally cooled to 100°C and removed to obtain a Cu-Cr-Zr-Ag multi-component alloy electrode film.

[0048] (5) The film was subjected to four-probe testing, AFM testing, tape testing, and XRF testing. The copper alloy film was found to have a silver content of 0.13 wt%, good electrical conductivity, a resistivity of 2.51 μΩ.cm (Glass-400°C), a surface roughness as low as 1.23 nm, a reflectivity exceeding 60%, and a bonding strength of 4B.

[0049] Example 3

[0050] (1) Cleaning the flexible substrate: First, a 10 × 10 mm PI substrate was exposed to UV light for 120 seconds to decompose any organic contaminants on the surface. After cleaning, the substrate was ultrasonically cleaned twice with deionized water for 15 minutes each time to remove water-soluble contaminants. The substrate was then ultrasonically cleaned with isopropyl alcohol for 15 minutes to remove any remaining contaminants and moisture. The substrate was placed in a constant temperature drying oven at 80°C for at least 2 hours to obtain a clean and dry substrate.

[0051] (2) Target polishing: Target 1 is Cu-0.12wt%Cr-0.08wt%Zr and target 2 is Cu-0.1wt%Ag alloy target. The sputtering surfaces of the targets are polished using 200-mesh, 800-mesh, and 2000-mesh sandpaper, respectively.

[0052] (3) Pulsed DC magnetron sputtering of a copper alloy film was performed. First, the gas pressure was controlled to 0.2 mToor and the argon flow rate was controlled to 25 sccm, and a pre-sputtering treatment was performed for 100 s. After the pre-sputtering, the sputtering power of target 1 was controlled to 100 W, and the sputtering power of target 2 was controlled to 60 W. Pulsed DC magnetron sputtering was performed for 600 s to finally obtain a CCZA alloy film.

[0053] (4) Nitrogen atmosphere high-temperature annealing: The film was placed in an RTA rapid annealing heat treatment furnace and nitrogen was introduced to maintain the pressure at 600 mTorr. The temperature was raised from room temperature to 400°C at a rate of 30°C / s and then maintained for 30 min. The film was then naturally cooled to 100°C and removed to obtain a Cu-Cr-Zr-Ag multi-component alloy electrode film.

[0054] (5) The film was subjected to four-probe testing, AFM testing, tape testing, and XRF testing. The copper alloy film was found to have a silver content of 0.14 wt%, good electrical conductivity, a resistivity of 2.48 μΩ.cm (PI-400°C), a surface roughness as low as 1.23 nm, a reflectivity of over 60%, and a bonding strength of 4B.

[0055] Example 4

[0056] (1) Cleaning the flexible substrate: First, a 10 × 10 mm PI substrate was exposed to UV light for 120 seconds to decompose any organic contaminants on the surface. After cleaning, the substrate was ultrasonically cleaned twice with deionized water for 15 minutes each time to remove water-soluble contaminants. The substrate was then ultrasonically cleaned with isopropyl alcohol for 15 minutes to remove any remaining contaminants and moisture. The substrate was placed in a constant temperature drying oven at 80°C for at least 2 hours to obtain a clean and dry substrate.

[0057] (2) Target polishing: Target 1 is Cu-0.12wt%Cr-0.08wt%Zr and target 2 is Cu-0.1wt%Ag alloy target. The sputtering surfaces of the targets are polished using 200-mesh, 800-mesh, and 2000-mesh sandpaper, respectively.

[0058] (3) Pulsed DC magnetron sputtering of a copper alloy film was performed. First, the gas pressure was controlled to 0.2 mToor and the argon flow rate was controlled to 25 sccm, and a pre-sputtering treatment was performed for 100 s. After the pre-sputtering, the sputtering power of target 1 was controlled to 100 W and the sputtering power of target 2 was controlled to 70 W. Pulsed DC magnetron sputtering was performed for 600 s to finally obtain a CCZA alloy film.

[0059] (4) Nitrogen atmosphere high-temperature annealing: The film was placed in an RTA rapid annealing heat treatment furnace and nitrogen was introduced to maintain the pressure at 600 mTorr. The temperature was raised from room temperature to 400°C at a rate of 30°C / s and then maintained for 30 min. The film was then naturally cooled to 100°C and removed to obtain a Cu-Cr-Zr-Ag multi-component alloy electrode film.

[0060] (5) The film was subjected to four-probe testing, AFM testing, tape testing, and XRF testing. The copper alloy film was found to have a silver content of 0.16 wt%, good electrical conductivity, a resistivity of 2.43 μΩ.cm (PI-400°C), a surface roughness as low as 1.17 nm, a reflectivity of over 60%, and a bonding strength of 4B.

[0061] Comparative Example 1

[0062] (1) Cleaning the flexible substrate: First, a 10 × 10 mm PI substrate was exposed to UV light for 120 seconds to decompose any organic contaminants on the surface. After cleaning, the substrate was ultrasonically cleaned twice with deionized water for 15 minutes each time to remove water-soluble contaminants. The substrate was then ultrasonically cleaned with isopropyl alcohol for 15 minutes to remove any remaining contaminants and moisture. The substrate was placed in a constant temperature drying oven at 80°C for at least 2 hours to obtain a clean and dry substrate.

[0063] (2) Target polishing: Only target 1 with the composition of Cu-0.12wt%Cr-0.08wt%Zr was selected, and the sputtering surface of the target was polished using 200-mesh, 800-mesh, and 2000-mesh sandpaper.

[0064] (3) DC magnetron sputtering of a copper alloy thin film was performed. First, the gas pressure was controlled to 0.2 mToor, the argon flow rate was controlled to 25 sccm, and a pre-sputtering treatment was performed for 100 s. After the pre-sputtering, the sputtering power of target 1 was controlled to 100 W, and pulsed DC magnetron sputtering was performed for 600 s to finally obtain a CCZ alloy thin film.

[0065] (4) Nitrogen atmosphere high-temperature annealing: The film was placed in an RTA rapid annealing furnace and nitrogen was introduced to maintain the pressure at 600 mTorr. The temperature was raised from room temperature at a rate of 30°C / s to 400°C and held for 30 min. The film was then cooled naturally to 100°C and removed from the furnace.

[0066] (5) The film was subjected to four-probe, AFM, and XRF testing. The copper alloy film, under the same conditions, showed a conductivity of 3.43 μΩ·cm, a 30% difference from that of the film in Example 4. The surface roughness was 4.28 nm, an increase of approximately 300%. The reflectivity in the 370 nm to 700 nm wavelength range decreased by an average of 15%.

[0067] Comparative Example 2

[0068] (1) Cleaning the flexible substrate: First, a 10 × 10 mm PI substrate was exposed to UV light for 120 seconds to decompose any organic contaminants on the surface. After cleaning, the substrate was ultrasonically cleaned twice with deionized water for 15 minutes each time to remove water-soluble contaminants. The substrate was then ultrasonically cleaned with isopropyl alcohol for 15 minutes to remove any remaining contaminants and moisture. The substrate was placed in a constant temperature drying oven at 80°C for at least 2 hours to obtain a clean and dry substrate.

[0069] (2) Target polishing: Only target 1 with Cu-0.12wt%Cr-0.08wt%Zr and target 2 with Cu-0.1wt%Ag alloy targets were selected, and the sputtering surfaces of the targets were polished using 200-mesh, 800-mesh, and 2000-mesh sandpapers.

[0070] (3) DC magnetron sputtering of a copper alloy thin film was performed. First, the gas pressure was controlled to 0.2 mToor and the argon flow rate was controlled to 25 sccm, and a pre-sputtering treatment was performed for 100 s. After the pre-sputtering, the sputtering power of target 1 was controlled to 100 W and the sputtering power of target 2 was controlled to 120 W. Pulsed DC magnetron sputtering was performed for 600 s to finally obtain a CCZ alloy thin film.

[0071] (4) Nitrogen atmosphere high-temperature annealing: The film was placed in an RTA rapid annealing furnace and nitrogen was introduced to maintain the pressure at 600 mTorr. The temperature was raised from room temperature at a rate of 30°C / s to 400°C and held for 30 min. The film was then cooled naturally to 100°C and removed from the furnace.

[0072] (5) The film was tested by the tape method. The copper alloy film was tested and found to have a sharp decrease in bonding strength compared to the film in Example 4 under the same conditions, only maintaining a level of 2B.

[0073] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A highly reflective and highly conductive multi-component alloy electrode film, characterized in that: The alloy electrode film is a copper-based alloy having the following composition: Cu-Cr-Zr-Ag, wherein the content of Cu element is 99wt%-99.8wt%, the content of Cr element is 0.12wt%-0.3wt%, the content of Zr element is 0.05wt%-0.2wt%, and the content of Ag element is 0.1wt%-0.2wt%; The film has a thickness of 80 nm to 120 nm, a reflectivity of ≥60%, and a resistivity of ≤3 μΩ·cm.

2. The method for preparing a highly reflective and highly conductive multi-component alloy electrode film according to claim 1, wherein: The following steps are involved: (1) Cleaning the coating substrate and polishing the sputtering surface of the alloy target; (2) Fixing the substrate and target material in corresponding positions, setting the pulsed DC sputtering mode, selecting the dual-target magnetron co-sputtering process, and sputtering the alloy target material onto the substrate to obtain a thin film during the thin film deposition process; (3) The film obtained in step (2) is subjected to atmosphere annealing to finally obtain a Cu-Cr-Zr-Ag multi-component alloy electrode film.

3. The method for preparing a highly reflective and highly conductive multi-component alloy electrode film according to claim 2, wherein: The alloy target material in step (1) includes alloy target material 1 and alloy target material 2, wherein alloy target material 1 is a Cu-Cr-Zr ternary alloy target material, and alloy target material 2 is a Cu-Ag binary alloy target material.

4. The method for preparing a highly reflective and highly conductive multi-component alloy electrode film according to claim 2, wherein: The parameters of the dual-target magnetron co-sputtering process in step (2) are: duty cycle of 30%-60%, sputtering period of 20-50 μs, distance from target to substrate of 10-20 cm, sputtering pressure of 0.1 mTorr-0.3 mTorr, sputtering power of 40 W-120 W, and argon flow rate of 20 sccm-30 sccm.

5. The method for preparing a highly reflective and highly conductive multi-component alloy electrode film according to claim 2, wherein: The annealing atmosphere in step (3) is a nitrogen atmosphere, the pressure is controlled to be 600mToor-700mToor, the nitrogen flow rate is controlled to be 10sccm-15sccm, and the annealing time in the atmosphere is 30 to 60 minutes.

6. The method for preparing a highly reflective and highly conductive multi-component alloy electrode film according to claim 2, wherein: The polishing in step (1) is performed using sandpaper with a mesh size of 200-2000.

7. The method for preparing a highly reflective and highly conductive multi-component alloy electrode film according to claim 2, wherein: The substrate in step (1) is one of a PI substrate, a PEN substrate, a PE substrate, a PET substrate, and a CPI substrate, and the thickness of the substrate is 0.7 mm to 1 mm.

8. The method for preparing a highly reflective and highly conductive multi-component alloy electrode film according to claim 2, wherein: The annealing in step (3) is RTA rapid annealing treatment, with a heating rate of 30°C / s-50°C / s and a cooling rate of 2°C / min-3°C / min.

9. Application of the highly reflective and highly conductive multi-component alloy electrode film according to claim 1 in flexible wearable devices.

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