Flexible multilayer metal oxide film based on ion beam technology and preparation method and application thereof

Abstract

The invention discloses a flexible multilayer metal oxide thin film based on an ion beam technology, and belongs to the technical field of flexible thin films, and a preparation method of the thin film comprises the following specific steps: under a vacuum condition, metal oxide thin films are alternately deposited on a substrate through a magnetic filter cathode vacuum arc technology. Through the double-arc-head magnetic filter cathode vacuum arc deposition technology, the inorganic multilayer composite film can be directly prepared in the same chamber, the problems of complex procedures, pollution and the like of an alternate process are avoided, and meanwhile, the deposition energy such as arc current and negative bias parameters is adjusted when the metal oxide film is deposited, so that the deposition efficiency is improved. A compact phase can be formed at the interface of the multi-layer metal oxide thin film, the barrier property of the multi-layer composite thin film is further improved, and the requirements of OLED packaging are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible films, and in particular relates to a flexible multilayer metal oxide film based on ion beam technology, and a preparation method and application thereof. Background Art

[0002] Organic light-emitting diode (OLED) display technology is being widely researched and applied due to its advantages, including low energy consumption, lightweight, flexible, self-luminous, fast response time, and wide viewing angle. However, due to OLED's susceptibility to corrosion by moisture and oxygen, flexible OLED encapsulation has become a major challenge that needs to be addressed. Thin film encapsulation (TFE) technology is an effective means of extending the service life of flexible OLEDs. Among them, flexible metal oxide thin films have attracted widespread attention due to their excellent properties and have broad application prospects in flexible electronics and flexible packaging.

[0003] Research on encapsulation film deposition methods has mostly focused on ALD technology. ALD can form films uniformly, but due to its low deposition energy, it is difficult to ensure high density of the deposited film. The deposition process requires repeated gas purges, resulting in slow deposition rates. Furthermore, residual hydrogen can negatively impact OLEDs and thin-film transistors (TFTs). Furthermore, reports indicate that under high temperature and high humidity conditions, the hydrolysis of single-layer metal oxide films can accelerate their failure. Defects are inevitable in inorganic films during deposition, and water molecules can easily penetrate along these defects to reach the interface between the film and the substrate. This can reduce adhesion between the film and the substrate and accelerate film failure. Therefore, alternative methods are needed to improve the barrier properties of metal oxide films.

[0004] Currently, the commonly used method is to deposit a multilayer structure. In the organic / inorganic hybrid multilayer structure, the organic layer and the inorganic layer are deposited alternately to increase the permeation path of the entire barrier layer. However, the alternating vacuum process and the alternating vacuum and non-vacuum process will cause pollution, high cost and time-consuming problems, making large-scale production unrealistic.

[0005] Therefore, it is an urgent problem for those skilled in the art to provide a flexible film for OLED encapsulation that has good barrier properties, low cost, and can be mass-produced, and a preparation method thereof. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a flexible multilayer metal oxide film based on ion beam technology and a preparation method and application thereof.

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

[0008] A method for preparing a flexible multilayer metal oxide film based on ion beam technology comprises the following specific steps:

[0009] Under vacuum conditions, metal oxide films are alternately deposited on the substrate using magnetic filtered cathode vacuum arc technology.

[0010] Preferably, the metal oxide film is any two of Al2O3, ZrO2, TiO2, HfO2, MgO and ZnO films.

[0011] Preferably, the vacuum condition is 1-3×10 -3 Pa, and the argon flow rate is 6-16sccm.

[0012] Preferably, the thickness of each layer of the metal oxide film is 10-80 nm.

[0013] Preferably, the total thickness of the flexible multi-layer metal oxide film is 80-120 nm.

[0014] Preferably, the magnetic filtered cathode vacuum arc technology adopts a double-arc head magnetic filtered cathode vacuum arc equipment.

[0015] The two arc heads used in the present invention can be equipped with different target materials at the same time, and pollution caused by changing target materials can be avoided when preparing multi-layer flexible metal oxide films.

[0016] Preferably, in the magnetic filtered cathode vacuum arc technology, the arc current of the metal target is 30-70A, the flow rate of O2 is 6-50sccm, and the negative bias voltage is 1-7kV.

[0017] In the process of metal oxide thin film deposition, a high-power pulse negative bias is introduced. By adjusting the deposition energy during the deposition process, a new phase structure is formed at the interface (such as: ZrTi is generated at the interface between TiO2 and ZrO2). x O y , ZrAl is generated at the interface between Al2O3 and ZrO2 x O y ) leads to interface densification, further improving the barrier properties of the multilayer film, while reducing the internal stress of the film, making the film have both low stress and high barrier properties

[0018] A flexible multilayer metal oxide film based on ion beam technology is obtained by the preparation method described above.

[0019] Application of the flexible multilayer metal oxide film obtained by the preparation method described above in OLED packaging.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) To address the problem that hydrolysis of a single-layer metal oxide film accelerates its failure under high temperature and high humidity conditions, the present invention improves the water barrier properties of the film by depositing a composite multilayer structure;

[0022] (2) The use of alternating vacuum processes, alternating vacuum and non-vacuum processes for inorganic / organic overlapping and inorganic overlapping multi-layer packaging structures will cause pollution, high costs and time-consuming problems. The present invention uses a dual-arc head magnetic filtration cathode vacuum arc deposition technology to directly prepare inorganic multi-layer composite films in the same chamber, avoiding the complex procedures and pollution problems of the alternating process;

[0023] (3) Most of the current research on encapsulation film deposition methods focuses on ALD technology. Although ALD can form a film uniformly, it is difficult to ensure a high density of the deposited film due to its low deposition energy. In addition, the deposition process requires repeated gas purges, resulting in a slow deposition rate. Residual hydrogen will have a negative impact on OLEDs and thin-film transistors. The invention uses magnetic filtered cathode vacuum arc technology to deposit multi-layer composite films, which has the advantages of fast deposition, low deposition temperature, high film density, and no hydrogen during the deposition process.

[0024] (4) The present invention can form a dense phase at the interface of the multilayer metal oxide film by adjusting the deposition energy, such as arc current and negative bias voltage parameters, when depositing the metal oxide film, thereby further improving the barrier performance of the multilayer composite film. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 This is a structural diagram of the double-arc-head magnetic filtration cathode vacuum arc equipment of the present invention;

[0027] Figure 2 Schematic diagram of the composite film in Example 1 of the present invention;

[0028] Figure 3 Graphs showing the transmittance of the substrate, TiO2 film, and the composite film of the TiO2 film and liquid-like molecular brush in Example 1 of the present invention;

[0029] Figure 4 These are cross-sectional SEM images of the multilayer TiO2 / ZrO2 composite films prepared in Examples 1 and 2 of the present invention. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] Example 1

[0032] The present invention provides a flexible multilayer metal oxide film based on ion beam technology, comprising the following specific steps:

[0033] (1) Figure 1 A double-arc head magnetic filtered cathode vacuum arc equipment was used. In the figure, A and B are two arc heads, which were equipped with Ti and Zr metal targets respectively. Then the OLED device substrate (PEN) was placed in a vacuum chamber and the vacuum was pumped to 3×10 -3 Pa, argon gas was introduced at 6 sccm;

[0034] (2) Under vacuum conditions, the A arc head power supply is turned on, and the cathode target is mechanically triggered to generate arc discharge to form a metal plasma. The arc current is 60A, and the cathode arc discharge is 3 minutes to remove pollutants on the target surface. Then, 6 sccm of O2 is introduced, and the left magnetic field deflection is turned on. O2 is ionized under the action of the plasma to form O ions, and a TiO2 film is deposited on the substrate. The deposition time is 12 minutes, and the negative bias voltage is 3 kV.

[0035] (3) After arc head A discharge is completed, the base is turned to the direction of arc head B, and the power supply of arc head B is turned on. The cathode target is mechanically triggered to generate arc discharge to form metal plasma. The arc current is 60A and the cathode arc discharge is 3 minutes to remove pollutants on the target surface. Then 6sccm of O2 is introduced and the right magnetic field deflection is turned on. O2 is ionized under the action of plasma to form O ions, and ZrO2 thin film is deposited on the substrate. The deposition time is 10 minutes and the negative bias voltage is 3kV.

[0036] (4) repeating steps (2) and (3) once each, wherein the thickness of the ZrO2 film and the TiO2 film are 25 nm respectively, and the total thickness of the composite film is 100 nm. Upon completion, a flexible multilayer metal oxide film based on ion beam technology is obtained;

[0037] in, Figure 2 Schematic diagram of the structure of the flexible multilayer TiO2 / ZrO2 composite film in this embodiment, where two metal oxide films are deposited alternately, where 1 is a TiO2 film and 2 is a ZrO2 film;

[0038] Figure 3The transmittance graphs of multilayer TiO2 / ZrO2 composite films, TiO2 films, and ZrO2 films prepared for this example are shown. The thickness of the composite films, TiO2 films, and ZrO2 films is 100 nm, and all are prepared using magnetic filtration cathode vacuum technology. As can be seen from the graphs, the average transmittance of all films in the visible light range is above 85%.

[0039] The multilayer TiO2 / ZrO2 composite film, TiO2 film, and ZrO2 film prepared in this example were subjected to water vapor transmission rate tests at 85°C and 85% RH. The results are shown in Table 1.

[0040] Example 2

[0041] The present invention provides a flexible multilayer metal oxide film based on ion beam technology, comprising the following specific steps:

[0042] (1) Figure 1 A double-arc head magnetic filtered cathode vacuum arc equipment was used. In the figure, A and B are two arc heads, which were equipped with Ti and Zr metal targets respectively. Then the OLED device substrate (PEN) was placed in a vacuum chamber and the vacuum was pumped to 3×10 -3 Pa, argon gas was introduced at 6 sccm;

[0043] (2) Under vacuum conditions, the A arc head power supply is turned on, and the cathode target is mechanically triggered to generate arc discharge to form a metal plasma. The arc current is 60A, and the cathode arc discharge is 3 minutes to remove pollutants on the target surface. Then, 10 sccm of O2 is introduced, and the left magnetic field deflection is turned on. O2 is ionized under the action of the plasma to form O ions, and a TiO2 film is deposited on the substrate. The deposition time is 6 minutes and the negative bias voltage is 5 kV.

[0044] (3) After arc head A discharge is completed, the base is turned to the direction of arc head B, and the power supply of arc head B is turned on. The cathode target is mechanically triggered to generate arc discharge to form metal plasma. The arc current is 60A and the cathode arc discharge is 3 minutes to remove pollutants on the target surface. Then, 10 sccm of O2 is introduced and the right magnetic field deflection is turned on. O2 is ionized under the action of plasma to form O ions, and ZrO2 thin film is deposited on the substrate. The deposition time is 5 minutes and the negative bias voltage is 7 kV.

[0045] (4) Repeat steps (2) and (3) three times each, with the thickness of the ZrO2 film and the TiO2 film being 12.5 nm each time, and the total thickness of the composite film being 100 nm. After completion, a flexible multilayer metal oxide film based on ion beam technology is obtained. The relevant conclusions are shown in Table 1.

[0046] Figure 4The cross-sectional SEM images of the multilayer TiO2 / ZrO2 composite films prepared in Example 1 and Example 2 show that the thickness of the composite films is uniformly 100 nm. The cross-sectional images of all TiO2 / ZrO2 composite films show that there is no obvious distinction between the TiO2 part and the ZrO2 part, and the TiO2 / ZrO2 composite film with a modulation ratio of 4:4 has a denser structure than the composite film with a modulation ratio of 2:2.

[0047] Example 3

[0048] The present invention provides a flexible multilayer metal oxide film based on ion beam technology, comprising the following specific steps:

[0049] (1) Figure 1 A double-arc head magnetic filtered cathode vacuum arc equipment was used. In the figure, A and B are two arc heads, which were equipped with Ti and Zr metal targets respectively. Then the OLED device substrate (PEN) was placed in a vacuum chamber and the vacuum was pumped to 3×10 -3 Pa, argon gas was introduced at 6 sccm;

[0050] (2) Under vacuum conditions, the A arc head power supply is turned on, and the cathode target is mechanically triggered to generate arc discharge to form a metal plasma. The arc current is 60A, and the cathode arc discharge is 3 minutes to remove pollutants on the target surface. Then, 10 sccm of O2 is introduced, and the left magnetic field deflection is turned on. O2 is ionized under the action of the plasma to form O ions, and a TiO2 film is deposited on the substrate. The deposition time is 9 minutes and the negative bias voltage is 5 kV.

[0051] (3) After arc head A discharge is completed, the base is turned to arc head B, and the power supply of arc head B is turned on. The cathode target is mechanically triggered to generate arc discharge to form metal plasma. The arc current is 60A and the cathode arc discharge is performed for 3 minutes to remove pollutants on the target surface. Then, 10 sccm of O2 is introduced and the right magnetic field deflection is turned on. O2 is ionized under the action of plasma to form O ions, and ZrO2 thin film is deposited on the substrate. The deposition time is 9 minutes and the negative bias voltage is 7 kV.

[0052] (4) Repeat steps (2) and (3) once each. The thickness of the ZrO2 film and the TiO2 film are 20 nm each time, and the thickness of the total composite film is 80 nm. After completion, a flexible multilayer metal oxide film based on ion beam technology is obtained. The relevant test results are shown in Table 1.

[0053] Example 4

[0054] The present invention provides a flexible multilayer metal oxide film based on ion beam technology, comprising the following specific steps:

[0055] (1) Figure 1A double-arc head magnetic filtered cathode vacuum arc equipment was used. In the figure, A and B are two arc heads, which were equipped with Ti and Zr metal targets respectively. Then the OLED device substrate (PEN) was placed in a vacuum chamber and the vacuum was pumped to 3×10 -3 Pa, argon gas was introduced at 6 sccm;

[0056] (2) Under vacuum conditions, the A arc head power supply is turned on, and the cathode target is mechanically triggered to generate arc discharge to form a metal plasma. The arc current is 60A, and the cathode arc discharge is 3 minutes to remove pollutants on the target surface. Then, 10 sccm of O2 is introduced, and the left magnetic field deflection is turned on. O2 is ionized under the action of the plasma to form O ions, and a TiO2 film is deposited on the substrate. The deposition time is 9 minutes and the negative bias voltage is 5 kV.

[0057] (3) After arc head A discharge is completed, the base is turned to arc head B, and the power supply of arc head B is turned on. The cathode target is mechanically triggered to generate arc discharge to form metal plasma. The arc current is 60A and the cathode arc discharge is performed for 3 minutes to remove pollutants on the target surface. Then, 10 sccm of O2 is introduced and the right magnetic field deflection is turned on. O2 is ionized under the action of plasma to form O ions, and ZrO2 thin film is deposited on the substrate. The deposition time is 9 minutes and the negative bias voltage is 7 kV.

[0058] (4) Repeat steps (2) and (3) twice each. The thickness of the ZrO2 film and the TiO2 film are 20 nm each time, and the thickness of the total composite film is 120 nm. After completion, a flexible multilayer metal oxide film based on ion beam technology is obtained. The relevant test results are shown in Table 1.

[0059] Table 1 Water vapor transmission rate results of TiO2 film, ZrO2 film and multilayer TiO2 / ZrO2 composite film

[0060] sample <![CDATA[Water vapor transmission rate (10 -6 g / m 2 / day)]]> <![CDATA[TiO2 thin film]]> 4.9 <![CDATA[ZrO2 thin film]]> 4.2 <![CDATA[Multilayer TiO2 / ZrO2 composite thin film (Example 1)]]> 2.9 <![CDATA[Multilayer TiO2 / ZrO2 composite thin film (Example 2)]]> 1.49 <![CDATA[Multi-layer TiO2 / ZrO2 composite thin film (Example 3)]]> 3.3 <![CDATA[Multi-layer TiO2 / ZrO2 composite thin film (Example 4)]]> 2.1

[0061] It can be seen from the table that the WVTR of TiO2 / ZrO2 composite film is 1.49×10 -6 g / m 2 / day, which is 3 times lower than that of TiO2 film and ZrO2 film; and in Example 2, the maximum negative bias voltage is 7kV, the film is denser, and the water vapor permeability is lower than that of Example 1 (negative bias voltage is 3kV); Example 3 has the same number of layers as Example 1, but the overall thickness is 80nm, resulting in an increase in water vapor permeability; Compared with Example 3, Example 4 has an increased thickness and number of layers, and thus the water vapor permeability is further reduced.

[0062] The various embodiments are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to in detail.

[0063] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a flexible multilayer metal oxide film based on ion beam technology, characterized in that: The specific steps include: Under vacuum conditions, metal oxide films are alternately deposited on the substrate using magnetic filtered cathode vacuum arc technology.

2. The method for preparing a flexible multilayer metal oxide film based on ion beam technology according to claim 1, characterized in that: The metal oxide thin films are any two of Al2O3, ZrO2, TiO2, HfO2, MgO and ZnO thin films.

3. The method for preparing a flexible multilayer metal oxide film based on ion beam technology according to claim 1, characterized in that: The vacuum condition is 1-3×10 -3 Pa, and the argon flow rate is 6-16sccm.

4. The method for preparing a flexible multilayer metal oxide film based on ion beam technology according to claim 1, characterized in that: The thickness of each layer of the metal oxide film is 10-80 nm.

5. The method for preparing a flexible multilayer metal oxide film based on ion beam technology according to claim 1, characterized in that: The total thickness of the flexible multi-layer metal oxide film is 80-120 nm.

6. The method for preparing a flexible multilayer metal oxide film based on ion beam technology according to claim 1, characterized in that: The magnetic filtered cathode vacuum arc technology adopts a double arc head magnetic filtered cathode vacuum arc device.

7. The method for preparing a flexible multilayer metal oxide film based on ion beam technology according to claim 1, characterized in that: In the magnetic filtered cathode vacuum arc technology, the arc current of the metal target is 30-70A, the flow rate of O2 is 6-50sccm, and the negative bias voltage is 1-7kV.

8. A flexible multilayer metal oxide film obtained by the preparation method according to any one of claims 1 to 7 based on ion beam technology.

9. Use of the flexible multilayer metal oxide film obtained by the preparation method according to any one of claims 1 to 7 in OLED packaging.

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