Plasma etching method and coating method based on boron target magnetron sputtering

Abstract

The present invention discloses a plasma etching method and a film coating method based on magnetron sputtering of a boron target material, and belongs to the technical field of thin film material preparation. The plasma etching method comprises: in a vacuum chamber of a magnetron sputtering device, a substrate is mounted on a sample holder, and a boron target material is mounted on a cathode; the vacuum chamber of the magnetron sputtering device is evacuated, argon gas is introduced, a bipolar pulse bias is applied to the substrate, radio frequency is applied to the boron target material, and then plasma etching of the substrate is achieved through the magnetron sputtering device. The film coating method comprises: the substrate after plasma etching does not need to be taken out of the vacuum chamber of the magnetron sputtering device, and magnetron sputtering coating is directly performed in the vacuum chamber of the magnetron sputtering device. The present invention can realize plasma etching in the magnetron sputtering device without the need for vacuum chamber modification, and the scheme is highly operational and practical.

Description

Technical Field

[0001] The present invention belongs to the technical field of thin film material preparation, and in particular relates to a plasma etching method and a film coating method based on boron target magnetron sputtering. Background Art

[0002] Magnetron sputtering is a type of physical vapor deposition that can be used to prepare a variety of materials such as metals, semiconductors, and insulators. It has the advantages of simple equipment, easy control, large coating area, and strong adhesion, and is widely used in real production and life. Before magnetron sputtering is performed, it is very necessary to perform surface treatment on the substrate. This is because the surface of the substrate is often contaminated with various impurities, such as oil, dust, fingerprints, etc. These impurities will affect the quality of the coating layer, making the film layer uneven or defective, and will also affect the adhesion of the film layer. Even if there are no impurities on the surface of the substrate, the oxide of the substrate will affect the adhesion of the film layer. Therefore, surface treatment of the substrate can remove impurities and oxides attached to the surface, providing the necessary guarantee for achieving high-quality thin film coating.

[0003] Substrate surface treatment primarily involves wet processing and plasma dry processing. Plasma etching, a physical etching method for substrate surfaces, offers advantages such as environmental friendliness and high control precision. Plasma etching generally requires customized, specialized equipment. For example, adding plasma etching functionality to coating equipment like magnetron sputtering requires modifying the existing equipment's vacuum chamber (for example, customizing an ion source), which is time-consuming, labor-intensive, and expensive. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] To this end, a first aspect of the present invention provides a plasma etching method based on boron target magnetron sputtering, comprising:

[0006] In the vacuum chamber of the magnetron sputtering equipment, a substrate is mounted on the sample holder and a boron target is mounted on the cathode;

[0007] The vacuum chamber of the magnetron sputtering device is evacuated, and then argon gas is introduced, a bipolar pulse bias is applied to the substrate, and radio frequency is applied to the boron target material, and then plasma etching of the substrate is achieved through the magnetron sputtering device.

[0008] Furthermore, the substrate includes a copper substrate, an aluminum substrate, a molybdenum substrate, a niobium substrate, a tantalum substrate, a zirconium substrate, a tungsten substrate or a silicon substrate.

[0009] Furthermore, a bipolar pulse bias is applied to the substrate, wherein the positive pulse bias is 90V to 110V, the negative pulse bias is -500V to -800V, the frequency is 25KHz to 35KHz, and the duty cycle is 70% to 90%.

[0010] Furthermore, radio frequency is applied to the boron target, and the radio frequency power is 80W to 120W.

[0011] Furthermore, the etching rate of the copper substrate is 2.5nm / min to 2.6nm / min; the etching rate of the aluminum substrate is 0.6nm / min to 0.7nm / min; the etching rate of the molybdenum substrate is 1.3nm / min to 1.4nm / min; the etching rate of the niobium substrate is 1.3nm / min to 1.4nm / min; the etching rate of the tantalum substrate is 1.7nm / min to 1.8nm / min; the etching rate of the zirconium substrate is 1.0nm / min to 1.1nm / min; the etching rate of the tungsten substrate is 0.85nm / min to 0.95nm / min; and the etching rate of the silicon substrate is 1.45nm / min to 1.55nm / min.

[0012] Furthermore, the vacuum chamber of the magnetron sputtering device is evacuated to a vacuum degree of less than 5.0×10 -4 Pa.

[0013] Furthermore, argon gas is introduced to a vacuum degree of 0.3-0.4 Pa.

[0014] A second aspect of the present invention provides a film coating method, comprising:

[0015] Plasma etching: using the above-mentioned plasma etching method to perform plasma etching on the substrate;

[0016] Magnetron sputtering coating: after the substrate is plasma etched, it does not need to be taken out from the vacuum chamber of the magnetron sputtering equipment, and magnetron sputtering coating is directly performed in the vacuum chamber of the magnetron sputtering equipment.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] The plasma etching method based on boron target magnetron sputtering provided by the present invention utilizes existing magnetron sputtering equipment to perform plasma etching on the substrate to be etched, eliminating the need to modify the vacuum chamber of the existing magnetron sputtering equipment. This method is highly operational and practical. After plasma etching, the substrate can be directly subjected to the coating process in the vacuum chamber of the magnetron sputtering equipment, effectively preventing secondary contamination of the substrate after plasma etching. DETAILED DESCRIPTION

[0019] In order to better understand the above technical solution, the technical solution of the embodiment of the present application is described in detail below through specific examples. It should be understood that the embodiment of the present application and the specific features in the embodiment are detailed descriptions of the technical solution of the embodiment of the present application, rather than limitations on the technical solution of the present application. In the absence of conflict, the embodiment of the present application and the technical features in the embodiment can be combined with each other.

[0020] A first aspect of an embodiment of the present invention provides a plasma etching method based on boron target magnetron sputtering, comprising:

[0021] In the vacuum chamber of the magnetron sputtering equipment, a substrate is mounted on the sample holder and a boron target is mounted on the cathode;

[0022] The vacuum chamber of the magnetron sputtering device is evacuated, and then argon gas is introduced, a bipolar pulse bias is applied to the substrate, and radio frequency is applied to the boron target material, and then plasma etching of the substrate is achieved through the magnetron sputtering device.

[0023] The plasma etching method based on boron target magnetron sputtering provided in an embodiment of the present invention utilizes existing magnetron sputtering equipment to achieve plasma etching of a substrate without the need to modify the vacuum chamber of the existing magnetron sputtering equipment. The solution is highly operational and practical.

[0024] It can be understood that the embodiment of the present invention provides a method for adding a plasma physical etching function to a magnetron sputtering device without changing the vacuum chamber conditions of the magnetron sputtering device, thereby solving the problem in the prior art that adding a plasma etching function to an existing magnetron sputtering device requires time-consuming and labor-intensive customization of the vacuum chamber. This method only requires providing a bipolar pulse bias power supply and a boron target material. Both the bipolar pulse bias power supply and the boron target material are commercial standard products that are easy to purchase. Online plasma physical etching of the substrate can be achieved without any modification to the vacuum chamber, and the method has strong feasibility and high application value.

[0025] In some embodiments, the substrate includes a copper substrate, an aluminum substrate, a molybdenum substrate, a niobium substrate, a tantalum substrate, a zirconium substrate, a tungsten substrate, or a silicon substrate.

[0026] We used a plasma etching method based on boron target magnetron sputtering to perform plasma etching on copper substrates, aluminum substrates, molybdenum substrates, niobium substrates, tantalum substrates, zirconium substrates, tungsten substrates and silicon substrates respectively. We found that this method can achieve plasma etching of the above-mentioned different substrate materials, but there are obvious differences in the etching rates.

[0027] Through a large number of experiments, we summarized the etching rates of commonly used substrate materials based on applying radio frequency to the boron target with an RF power of 80W to 120W and applying a bipolar pulse bias to the substrate to be etched, where the positive pulse bias is 90V to 110V, the negative pulse bias is -500V to -800V, the frequency is 25KHz to 35KHz, and the duty cycle is 70% to 90%. Specifically, the etching rate of copper substrate is 2.5~2.6nm / min; the etching rate of aluminum substrate is 0.6~0.7nm / min; the etching rate of molybdenum substrate is 1.3~1.4nm / min; the etching rate of niobium substrate is 1.3~1.4nm / min; the etching rate of tantalum substrate is 1.7~1.8nm / min; the etching rate of zirconium substrate is 1.0~1.1nm / min; the etching rate of tungsten substrate is 0.85~0.95nm / min; and the etching rate of silicon substrate is 1.45~1.55nm / min.

[0028] It is understandable that the plasma etching method based on boron target magnetron sputtering of the present application can determine the etching time for different substrates according to the required etching thickness and the etching rate of different substrates.

[0029] In some embodiments, a bipolar pulse bias is applied to the substrate, wherein the positive pulse bias is 90V to 110V, the negative pulse bias is -500V to -800V, the frequency is 25KHz to 35KHz, and the duty cycle is 70% to 90%.

[0030] Specifically, our experiments unexpectedly discovered that by installing a boron target on the cathode of a magnetron sputtering device and applying a bipolar pulse bias to the substrate, plasma etching of the substrate can be achieved in the vacuum chamber of an existing magnetron sputtering device. We tried installing nickel and gold targets on the cathode of the magnetron sputtering device, and explored the parameters for applying a bipolar pulse bias to the substrate (including positive pulse bias, negative pulse bias, frequency, and duty cycle). Ultimately, we concluded that by installing a boron target on the cathode of the magnetron sputtering device and applying a bipolar pulse bias to the substrate with the following parameters: positive pulse bias of 90V to 110V, negative pulse bias of -500V to -800V, frequency of 25kHz to 35kHz, and duty cycle of 70% to 90%, plasma etching by magnetron sputtering can be achieved.

[0031] In some embodiments, radio frequency is applied to the boron target, and the radio frequency power is 80W to 120W.

[0032] It is understandable that RF power affects the coating rate. We have also found that RF power affects the etching rate. The RF power can be set according to the methods in the prior art. We preferably apply RF power of 80W to 120W to the boron target.

[0033] In some embodiments, the vacuum chamber of the magnetron sputtering device is evacuated to a vacuum degree of less than 5.0×10 -4 Pa.

[0034] It is understandable that the higher the vacuum degree of the vacuum chamber of the magnetron sputtering equipment, the less impurities there are in the chamber, which in turn reduces the impact on etching. Experiments have found that when the vacuum degree is controlled to be less than 5.0×10 -4 Pa, which can meet our experimental requirements.

[0035] In some embodiments, argon gas is introduced to a vacuum degree of 0.3-0.4 Pa.

[0036] It is understandable that the purpose of introducing argon gas is to generate plasma ignition, and controlling the argon gas pressure at 0.3-0.4 Pa is more suitable for plasma etching of the substrate in the vacuum chamber of the magnetron sputtering equipment.

[0037] A second aspect of an embodiment of the present invention provides a film coating method, comprising:

[0038] Plasma etching: using the above-mentioned plasma etching method to perform plasma etching on the substrate;

[0039] Magnetron sputtering coating: after the substrate is plasma etched, it does not need to be taken out from the vacuum chamber of the magnetron sputtering equipment, and magnetron sputtering coating is directly performed in the vacuum chamber of the magnetron sputtering equipment.

[0040] The coating method provided in an embodiment of the present invention utilizes existing magnetron sputtering equipment to realize plasma etching of the substrate, without the need to modify the existing magnetron sputtering equipment, and the plasma physical etching process can be performed online in a vacuum. After the substrate is plasma etched, it can enter the coating process in a vacuum state, effectively ensuring that the substrate after plasma etching is not contaminated again, and has high application value in the field of coating.

[0041] Example 1 A plasma etching method based on magnetron sputtering of boron target

[0042] A plasma etching method based on boron target magnetron sputtering comprises the following steps:

[0043] 1) In the vacuum chamber of the magnetron sputtering equipment, the substrate to be plasma etched is mounted on the sample holder, a bipolar pulse bias power supply is connected to the sample holder, and a boron target is mounted on the cathode.

[0044] 2) Close the vacuum chamber door of the magnetron sputtering equipment and evacuate the chamber to a vacuum degree of less than 5.0×10 -4 Pa.

[0045] 3) Introduce argon gas into the vacuum chamber of the magnetron sputtering equipment to a vacuum degree of 0.33 Pa;

[0046] Radio frequency is applied to the boron target, with a radio frequency of 13.56 MHz and a radio frequency power of 100 W;

[0047] A positive pulse bias of 100 V and a negative pulse bias of -500 V were applied to the sample holder with the substrate mounted thereon, with a frequency of 30 kHz and a duty cycle of 89%.

[0048] 4) Open the substrate baffle and perform plasma etching on the substrate until the required etching thickness is reached.

[0049] We used the method of Example 1 to test different types of substrate materials and found that the etching rates of different substrate materials were different. The test results are shown in Table 1.

[0050] Table 1 Etching rates of different substrate materials in Example 1

[0051]

[0052] Comparative Example 1: A plasma etching method based on magnetron sputtering of boron target

[0053] Comparative Example 1 differs from Example 1 in that a bipolar pulse bias is not applied in step 3). The method of Comparative Example 1 was used to plasma etch substrates of various materials listed in Table 1. The method of Comparative Example 1 failed to achieve plasma etching on the substrates; instead, a boron film was deposited on the substrates.

[0054] Comparative Example 2: A plasma etching method based on magnetron sputtering of boron target

[0055] Comparative Example 2 differs from Example 1 in that, in step 3), the applied positive pulse bias voltage was 500V, the negative pulse bias voltage was -100V, the frequency was 30 kHz, and the duty cycle was 89%. The method of Comparative Example 2 was used to perform plasma etching on substrates of various materials listed in Table 1. The results showed that the method of Comparative Example 2 failed to achieve plasma etching on the substrates; instead, a boron film was deposited on the substrates.

[0056] Comparative Example 3: A plasma etching method based on gold target magnetron sputtering

[0057] Comparative Example 3 differs from Example 1 in that an Au target was installed on the cathode of the magnetron sputtering apparatus. We plasma-etched substrates of various materials listed in Table 1 using the method of Comparative Example 3. The results showed that the method of Comparative Example 3 failed to plasma-etch the substrates; instead, a layer of Au film was deposited on the substrates.

[0058] Comparative Example 4: A plasma etching method based on nickel target magnetron sputtering

[0059] Comparative Example 4 differs from Example 1 in that a Ni target was installed on the cathode of the magnetron sputtering apparatus. We plasma-etched substrates of various materials listed in Table 1 using the method of Comparative Example 4. The results showed that the method of Comparative Example 4 failed to etch the substrates; instead, a Ni film was deposited on the substrates.

[0060] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application. The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application. These improvements and variations should also be regarded as the scope of protection of the present application.

Claims

1. A plasma etching method based on boron target magnetron sputtering, characterized in that: include: In the vacuum chamber of the magnetron sputtering equipment, a substrate is mounted on the sample holder and a boron target is mounted on the cathode; The vacuum chamber of the magnetron sputtering device is evacuated, and then argon gas is introduced, a bipolar pulse bias is applied to the substrate, and a radio frequency is applied to the boron target material, thereby performing plasma etching on the substrate through the magnetron sputtering device; The substrate is applied with a bipolar pulse bias, wherein the positive pulse bias is 90V to 110V, the negative pulse bias is -500V to -800V, the frequency is 25KHz to 35KHz, and the duty cycle is 70% to 90%; The radio frequency is applied to the boron target, and the radio frequency power is 80W to 120W.

2. The plasma etching method based on boron target magnetron sputtering according to claim 1, characterized in that: The substrate includes a copper substrate, an aluminum substrate, a molybdenum substrate, a niobium substrate, a tantalum substrate, a zirconium substrate, a tungsten substrate or a silicon substrate.

3. The plasma etching method based on boron target magnetron sputtering according to claim 2, characterized in that: The etching rate of the copper substrate is 2.5nm / min to 2.6nm / min; the etching rate of the aluminum substrate is 0.6nm / min to 0.7nm / min; the etching rate of the molybdenum substrate is 1.3nm / min to 1.4nm / min; the etching rate of the niobium substrate is 1.3nm / min to 1.4nm / min; the etching rate of the tantalum substrate is 1.7nm / min to 1.8nm / min; the etching rate of the zirconium substrate is 1.0nm / min to 1.1nm / min; the etching rate of the tungsten substrate is 0.85nm / min to 0.95nm / min; and the etching rate of the silicon substrate is 1.45nm / min to 1.55nm / min.

4. The plasma etching method based on boron target magnetron sputtering according to claim 1, characterized in that: The vacuum chamber of the magnetron sputtering equipment is evacuated to a vacuum degree of less than 5.0×10 -4 Pa.

5. The plasma etching method based on boron target magnetron sputtering according to claim 4, characterized in that: Argon gas is introduced to a vacuum degree of 0.3-0.4 Pa.

6. A film coating method, characterized in that: include: Plasma etching, using the plasma etching method according to any one of claims 1 to 5 to perform plasma etching on the substrate; Magnetron sputtering coating: after the substrate is plasma etched, it does not need to be taken out from the vacuum chamber of the magnetron sputtering equipment, and magnetron sputtering coating is directly performed in the vacuum chamber of the magnetron sputtering equipment.

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