An aluminum or aluminum alloy thin film, its preparation method and application

Abstract

This application discloses an aluminum or aluminum alloy thin film, its preparation method, and its application, relating to the field of thin film materials technology. The aluminum or aluminum alloy thin film of this application comprises a substrate, a first Cr layer, an aluminum or aluminum alloy layer, and a second Cr layer stacked sequentially. Not only does the aluminum or aluminum alloy layer exhibit good adhesion to the substrate and is not easily detached, but the thin film also has low resistance, making it suitable for application in the gate electrode of thin-film transistor liquid crystal displays.

Description

Technical Field

[0001] This application relates to the field of thin film materials technology, specifically to an aluminum or aluminum alloy thin film, its preparation method, and its application. Background Technology

[0002] Aluminum (Al) is widely used in electronic devices such as touch screens and displays due to its light weight and excellent electrical and thermal conductivity, reflectivity, and oxidation resistance. The gate electrode of a thin-film transistor liquid crystal display (TFT-LCD) is typically made of aluminum or an aluminum alloy.

[0003] In recent years, DC magnetron sputtering has gradually replaced traditional wet etching processes for fabricating gate electrodes for TFT-LCDs. However, when depositing aluminum or aluminum alloy layers on a substrate using DC magnetron sputtering, the adhesion between the aluminum or aluminum alloy layer and the substrate is low, leading to problems such as detachment. Adjusting sputtering parameters, including but not limited to power, temperature, and operating pressure, has not effectively improved this issue. Therefore, it is necessary to develop a technology to effectively improve the adhesion of aluminum or aluminum alloy layers to the substrate and to achieve lower resistance. Summary of the Invention

[0004] Based on the deficiencies of the existing technology, the purpose of this application is to provide an aluminum or aluminum alloy thin film, its preparation method and application, which aims to effectively improve the adhesion of the aluminum or aluminum alloy layer on the substrate and make it have a lower resistance.

[0005] To achieve the above objectives, this application provides an aluminum or aluminum alloy thin film comprising a substrate, a first Cr (chromium) layer, an Al or Al alloy layer, and a second Cr layer stacked sequentially.

[0006] The aforementioned aluminum or aluminum alloy thin film enhances the adhesion of the Al or Al alloy layer to the substrate by setting a first Cr layer between the substrate and the aluminum or aluminum alloy layer; and protects the Al or Al alloy layer from being detached by external forces by setting a second Cr layer on the surface of the Al or Al alloy layer away from the substrate.

[0007] The aforementioned aluminum or aluminum alloy thin film not only exhibits good adhesion of the Al or Al alloy layer to the substrate, making it difficult to detach, but also has low resistance, making it suitable for use in the gate electrode of thin-film transistor liquid crystal displays.

[0008] In some embodiments, the thickness of the first Cr layer is 9-21 nm to improve adhesion and reduce resistance.

[0009] In some embodiments, the thickness of the second Cr layer is 9-21 nm to improve adhesion and reduce resistance.

[0010] In some embodiments, the thickness of the Al or Al alloy layer is 60-80 nm.

[0011] In some embodiments, at least one of (1) to (2) is also satisfied:

[0012] (1) The Al alloy layer includes an Al alloy, wherein the Al alloy includes at least one of AlSi and AlNd.

[0013] (2) The substrate is glass with an alkali content ≤0.05wt% and a thermal expansion coefficient ≤35.5×10 at 25℃. -7 / K, with a thickness of 0.2-1.1mm.

[0014] Optionally, the alkali content of the substrate is 0.05 wt% or 0.02 wt%, etc. Optionally, the coefficient of thermal expansion of the substrate at 25°C is 35.5 × 10⁻⁶. -7 / K or 30×10 -7 / K etc.

[0015] This application also provides a method for preparing the aluminum or aluminum alloy thin film, comprising the following steps:

[0016] A first Cr layer is prepared on at least one side of a substrate using a first DC magnetron sputtering process;

[0017] An Al or Al alloy layer is prepared on the surface of the first Cr layer away from the substrate using a second DC magnetron sputtering process;

[0018] A second Cr layer is prepared on the surface of the Al or Al alloy layer away from the substrate using a third DC magnetron sputtering process.

[0019] In some embodiments, the first DC magnetron sputtering process, the second DC magnetron sputtering process, and the third DC magnetron sputtering process are each independent and all satisfy the following conditions:

[0020] The distance between the center of the target and the substrate is 6-13 cm;

[0021] The sputtering power density of the target is 2.5-5.5 W / cm³. 2 ;

[0022] The sputtering pressure is 0.4-0.8 Pa;

[0023] The growth temperature is 20-30℃.

[0024] In some embodiments, when preparing the first Cr layer and the second Cr layer, the target material used is a Cr target material with a purity ≥ 99.999 wt% (e.g., 99.9990 wt%, 99.9995 wt%, etc.) and a density ≥ 7.19 g / cm³. 3 (e.g., 7.19 g / cm³) 3 7.20g / cm 3 wait);

[0025] When preparing the Al layer, the target material used is an Al target with a purity ≥ 99.999% (e.g., 99.9990wt%, 99.9995wt%, etc.) and a density ≥ 2.7 g / cm³. 3 (e.g., 2.7g / cm) 3 2.8g / cm 3 wait);

[0026] When preparing the Al alloy layer, the target material used includes at least one of AlSi target and AlNd target.

[0027] In some embodiments, the AlSi target material has a purity ≥ 99.999 wt% (e.g., 99.9990 wt%, 99.9995 wt%, etc.) and a density ≥ 2.7 g / cm³. 3 (e.g., 2.7g / cm) 3 2.8g / cm 3 wait).

[0028] In some embodiments, the AlNd target material has a purity ≥ 99.999 wt% (e.g., 99.9990 wt%, 99.9995 wt%, etc.) and a density ≥ 2.7 g / cm³. 3 (e.g., 2.7g / cm) 3 2.8g / cm 3 wait).

[0029] In some embodiments, before preparing the first Cr layer, the substrate is first cleaned. The substrate cleaning steps include: ultrasonic cleaning with acetone, anhydrous ethanol and deionized water in sequence, and then drying with at least one of nitrogen and inert gas.

[0030] This application further provides the application of the aluminum or aluminum alloy thin film in the gate electrode of a thin-film transistor liquid crystal display.

[0031] Compared with the prior art, the beneficial effects of this application are as follows:

[0032] (1) This application enhances the adhesion of the Al or Al alloy layer to the substrate by setting a first Cr layer between the substrate and the Al or Al alloy layer; and protects the Al or Al alloy layer from being affected by external forces by setting a second Cr layer on the surface of the Al or Al alloy layer away from the substrate.

[0033] (2) The aluminum or aluminum alloy thin film of this application not only has good adhesion to the substrate and is not easy to fall off, but also has low resistance, making it suitable for the gate electrode of thin film transistor liquid crystal display. Attached Figure Description

[0034] Figure 1 It serves as an adhesion test evaluation standard. Detailed Implementation

[0035] To better illustrate the purpose, technical solutions, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are commonly used reagents and instruments. In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0036] Example 1

[0037] This embodiment provides a method for preparing aluminum thin film, including the following steps:

[0038] A metallic Cr target with a purity of 99.999 wt% and a density of 7.19 g / cm³ is installed on cathode target site 1. 3 ;

[0039] A metallic Al target with a purity of 99.999 wt% and a density of 2.7 g / cm³ is installed on cathode target site 2. 3 ;

[0040] Glass was used as the substrate, with an alkali content of 0.03 wt% and a thermal expansion coefficient of 30.5 × 10⁻⁶ at 25°C. -7 / K, with a thickness of 0.6mm, was first ultrasonically cleaned with acetone, then ultrasonically cleaned with anhydrous ethanol, then ultrasonically cleaned with deionized water, and finally dried with nitrogen to obtain the cleaned substrate.

[0041] Using the aforementioned metallic Cr target and employing a first DC magnetron sputtering process, a first Cr layer is prepared on one side of a cleaned substrate, wherein the first DC magnetron sputtering process satisfies:

[0042] The center distance between the target and the substrate is 6 cm;

[0043] The sputtering power density of the target is 3W / cm². 2 ;

[0044] The sputtering pressure is 0.6 Pa;

[0045] The growth temperature is 25℃;

[0046] The thickness of the first Cr layer is 15 nm;

[0047] Using the aforementioned Al metal target and employing a second DC magnetron sputtering process, an Al layer is prepared on the surface of the first Cr layer away from the substrate, wherein the second DC magnetron sputtering process satisfies:

[0048] The center distance between the target and the substrate is 6 cm;

[0049] The sputtering power density of the target is 3W / cm². 2 ;

[0050] The sputtering pressure is 0.6 Pa;

[0051] The growth temperature is 25℃;

[0052] The Al layer thickness is 70 nm;

[0053] Using the aforementioned metallic Cr target and employing a third DC magnetron sputtering process, a second Cr layer is prepared on the surface of the Al layer away from the substrate, thus obtaining an aluminum thin film. The third DC magnetron sputtering process satisfies the following conditions:

[0054] The center distance between the target and the substrate is 6 cm;

[0055] The sputtering power density of the target is 3W / cm². 2 ;

[0056] The sputtering pressure is 0.6 Pa;

[0057] The growth temperature is 25℃;

[0058] The second Cr layer has a thickness of 15 nm.

[0059] Example 2

[0060] This embodiment provides a method for preparing aluminum thin film, including the following steps:

[0061] A metallic Cr target with a purity of 99.999 wt% and a density of 7.19 g / cm³ is installed on cathode target site 1. 3 ;

[0062] A metallic Al target with a purity of 99.999 wt% and a density of 2.7 g / cm³ is installed on cathode target site 2. 3 ;

[0063] Glass was used as the substrate, with an alkali content of 0.03 wt% and a thermal expansion coefficient of 30.5 × 10⁻⁶ at 25°C. -7 / K, with a thickness of 0.2mm, was first ultrasonically cleaned with acetone, then ultrasonically cleaned with anhydrous ethanol, then ultrasonically cleaned with deionized water, and finally dried with nitrogen to obtain the cleaned substrate.

[0064] Using the aforementioned metallic Cr target and employing a first DC magnetron sputtering process, a first Cr layer is prepared on one side of a cleaned substrate, wherein the first DC magnetron sputtering process satisfies:

[0065] The distance between the center of the target and the center of the substrate is 10cm;

[0066] The sputtering power density of the target is 2.5 W / cm². 2 ;

[0067] The sputtering pressure is 0.4 Pa;

[0068] The growth temperature is 20℃;

[0069] The thickness of the first Cr layer is 10 nm;

[0070] Using the aforementioned Al metal target and employing a second DC magnetron sputtering process, an Al layer is prepared on the surface of the first Cr layer away from the substrate, wherein the second DC magnetron sputtering process satisfies:

[0071] The center distance between the target and the substrate is 13cm;

[0072] The sputtering power density of the target is 5.5 W / cm². 2 ;

[0073] The sputtering pressure is 0.8 Pa;

[0074] The growth temperature is 30℃;

[0075] The Al layer thickness is 80 nm;

[0076] Using the aforementioned metallic Cr target and employing a third DC magnetron sputtering process, a second Cr layer is prepared on the surface of the Al layer away from the substrate, thus obtaining an aluminum thin film. The third DC magnetron sputtering process satisfies the following conditions:

[0077] The distance between the center of the target and the center of the substrate is 10cm;

[0078] The sputtering power density of the target is 2.5 W / cm². 2 ;

[0079] The sputtering pressure is 0.4 Pa;

[0080] The growth temperature is 20℃;

[0081] The second Cr layer has a thickness of 10 nm.

[0082] Example 3

[0083] This embodiment provides a method for preparing aluminum thin film, including the following steps:

[0084] A metallic Cr target with a purity of 99.999 wt% and a density of 7.19 g / cm³ is installed on cathode target site 1.3 ;

[0085] A metallic Al target with a purity of 99.999 wt% and a density of 2.7 g / cm³ is installed on cathode target site 2. 3 ;

[0086] Glass was used as the substrate, with an alkali content of 0.03 wt% and a thermal expansion coefficient of 30.5 × 10⁻⁶ at 25°C. -7 / K, with a thickness of 1.1mm, was first ultrasonically cleaned with acetone, then ultrasonically cleaned with anhydrous ethanol, then ultrasonically cleaned with deionized water, and finally dried with nitrogen to obtain the cleaned substrate.

[0087] Using the aforementioned metallic Cr target and employing a first DC magnetron sputtering process, a first Cr layer is prepared on one side of a cleaned substrate, wherein the first DC magnetron sputtering process satisfies:

[0088] The center distance between the target and the substrate is 13cm;

[0089] The sputtering power density of the target is 5.5 W / cm². 2 ;

[0090] The sputtering pressure is 0.8 Pa;

[0091] The growth temperature is 30℃;

[0092] The thickness of the first Cr layer is 20 nm;

[0093] Using the aforementioned Al metal target and employing a second DC magnetron sputtering process, an Al layer is prepared on the surface of the first Cr layer away from the substrate, wherein the second DC magnetron sputtering process satisfies:

[0094] The distance between the center of the target and the center of the substrate is 10cm;

[0095] The sputtering power density of the target is 2.5 W / cm². 2 ;

[0096] The sputtering pressure is 0.4 Pa;

[0097] The growth temperature is 20℃;

[0098] The Al layer thickness is 60 nm;

[0099] Using the aforementioned metallic Cr target and employing a third DC magnetron sputtering process, a second Cr layer is prepared on the surface of the Al layer away from the substrate, thus obtaining an aluminum thin film. The third DC magnetron sputtering process satisfies the following conditions:

[0100] The center distance between the target and the substrate is 13cm;

[0101] The sputtering power density of the target is 5.5 W / cm². 2 ;

[0102] The sputtering pressure is 0.8 Pa;

[0103] The growth temperature is 30℃;

[0104] The thickness of the second Cr layer is 20 nm.

[0105] Example 4

[0106] This embodiment provides a method for preparing an aluminum alloy thin film. The difference from Embodiment 1 is that this embodiment uses an AlNd target instead of a metallic Al target, and the AlNd target has a purity of 99.999 wt% and a density of 2.7 g / cm³. 3 .

[0107] Example 5

[0108] This embodiment provides a method for preparing an aluminum alloy thin film. The difference from Embodiment 1 is that this embodiment uses an AlSi target instead of a metallic Al target, and the AlNd target has a purity of 99.999 wt% and a density of 2.7 g / cm³. 3 .

[0109] Example 6

[0110] This embodiment provides a method for preparing an aluminum thin film, which differs from Embodiment 1 in that the thickness of the first Cr layer is 5 nm and the thickness of the second Cr layer is 25 nm.

[0111] Example 7

[0112] This embodiment provides a method for preparing an aluminum thin film, which differs from Embodiment 1 in that the thickness of the first Cr layer is 25 nm and the thickness of the second Cr layer is 5 nm.

[0113] Comparative Example 1

[0114] This comparative example provides a method for preparing an aluminum thin film, which differs from Example 1 in that a first Cr layer is not prepared.

[0115] Comparative Example 2

[0116] This comparative example provides a method for preparing an aluminum thin film, which differs from Example 1 in that a second Cr layer is not prepared.

[0117] Comparative Example 3

[0118] This comparative example provides a method for preparing an aluminum thin film, which differs from Example 1 in that a first Cr layer and a second Cr layer are not prepared.

[0119] The aluminum or aluminum alloy films obtained in the above embodiments and comparative examples were subjected to the following tests:

[0120] Adhesion: Cross-cut adhesion test, using 3M 600 tape. See the test evaluation criteria below. Figure 1 ;

[0121] Sheet resistance: Tested using a sheet resistance tester;

[0122] The test results are shown in Table 1.

[0123] Table 1

[0124]

[0125]

[0126] As can be seen from the above data, the films in the embodiments of this application have high adhesion, ranging from 3B to 5B, and low sheet resistance, below 4.32Ω. Comparative Examples 1 to 3 have poor adhesion due to the lack of a first Cr layer and / or a second Cr layer.

[0127] As can be seen from Examples 1-3 and Examples 6-7, the thickness of the first Cr layer and the thickness of the second Cr layer affect the adhesion and resistance. Preferably, the thickness of the first Cr layer and the thickness of the second Cr layer are within 10-20 nm to obtain higher adhesion and lower resistance.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. An aluminum or aluminum alloy thin film for the gate electrode of a thin-film transistor liquid crystal display, characterized in that, It includes a substrate, a first Cr layer, an Al or Al alloy layer, and a second Cr layer stacked sequentially; the substrate is glass; the thickness of the first Cr layer is 9-21 nm; and the thickness of the second Cr layer is 9-21 nm.

2. The aluminum or aluminum alloy thin film as described in claim 1, characterized in that, The thickness of the Al or Al alloy layer is 60-80 nm.

3. The aluminum or aluminum alloy thin film as described in claim 1, characterized in that, It also satisfies at least one of (1) and (2): (1) The Al alloy layer comprises an Al alloy, wherein the Al alloy comprises at least one of AlSi and AlNd; (2) the substrate has an alkali element content of ≤0.05 wt%, a thermal expansion coefficient of ≤35.5 x 10 -7 / K at 25°C, and a thickness of 0.2-1.1 mm.

4. The method for preparing aluminum or aluminum alloy thin films according to any one of claims 1-3, characterized in that, Includes the following steps: A first Cr layer is prepared on at least one side of a substrate using a first DC magnetron sputtering process; An Al or Al alloy layer is prepared on the surface of the first Cr layer away from the substrate using a second DC magnetron sputtering process; A second Cr layer is prepared on the surface of the Al or Al alloy layer away from the substrate using a third DC magnetron sputtering process.

5. The method for preparing aluminum or aluminum alloy thin films as described in claim 4, characterized in that, The first DC magnetron sputtering process, the second DC magnetron sputtering process, and the third DC magnetron sputtering process are each independent and all satisfy the following: The distance between the center of the target and the substrate is 6-13 cm; The sputtering power density of the target is 2.5-5.5 W / cm³. 2 ; The sputtering pressure is 0.4-0.8 Pa; The growth temperature is 20-30℃.

6. The method for preparing aluminum or aluminum alloy thin films as described in claim 4, characterized in that, When preparing the first Cr layer and the second Cr layer, the target material used is a Cr target material with a purity ≥99.999wt% and a density ≥7.19g / cm³. When preparing the Al layer, the target material used is an Al target material with a purity ≥99.999wt% and a density ≥2.7g / cm³. When preparing the Al alloy layer, the target material used includes at least one of AlSi target and AlNd target.

7. The method for preparing aluminum or aluminum alloy thin films as described in claim 4, characterized in that, Before preparing the first Cr layer, the substrate is first cleaned. The substrate cleaning steps include: ultrasonic cleaning with acetone, anhydrous ethanol and deionized water in sequence, and then drying with at least one of nitrogen and inert gas.

8. The application of the aluminum or aluminum alloy thin film as described in any one of claims 1-3 in the gate electrode of a thin-film transistor liquid crystal display.

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