Method capable of adjusting carbon-oxygen ratio of thin film and hydrophobic film layer

Abstract

The invention provides a method capable of adjusting the carbon-oxygen ratio of a thin film. Compared with the prior art, the effect of adjusting the carbon-oxygen ratio of the thin film can be achieved only by adjusting the concentration change and / or the discharge power change of the organosiloxane monomer source in the reaction cavity, the method is simple and easy to implement, and continuous adjustment can be achieved. Furthermore, continuous adjustment of the carbon-oxygen ratio of the film layer can be achieved, the bottom of the film layer is of an oxygen-rich structure and has good adhesion to a substrate, the top of the film layer is made of carbon-rich components and has good hydrophobicity, the components of the film layer continuously change from bottom to top, the carbon-oxygen ratio gradually and continuously increases, and no film layer interface exists in the hydrophobic film. Therefore, on the premise of not introducing other oxide layers, not only is the adhesive force of the film layer to the substrate enhanced, but also the hydrophobicity of the top of the film layer is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical protective coatings, and in particular relates to a method capable of adjusting the carbon-oxygen ratio of a thin film and a hydrophobic film layer. Background Art

[0002] The hydrophobic coating (whose composition is SiO) was prepared by PECVD (plasma enhanced chemical vapor deposition) process using hexamethyldisiloxane (HMDSO). x C y ) has the advantages of low friction coefficient and good chemical stability. However, it often faces the problem of insufficient bonding during the preparation process. The hydrophobic film layer is easy to peel or fall off, especially in high stress or humid environments. It often faces the problem of bonding to the substrate, which greatly limits the further widespread application of this material. The usual solution is to introduce a transition layer between the film layer and the substrate, such as a silane coupling agent to improve the bonding of the surface functional film layer to the substrate. The principle is that one end of the silane coupling agent molecule is generally siloxane, and the other end is other functional groups. By pre-configuring a water / alcohol solution, one end of the siloxane is hydrolyzed to form a Si-OH group, which can form a covalent bond on the substrate to form a monolayer and expose the functional group at the other end to the substrate surface. In addition, depending on the different components to be coated, the functional group that has a good interaction with the raw material to be coated can be selected to increase the adhesion between the coating layer and the substrate. However, the transition layer is usually prepared by a wet process, which cannot meet the process requirements for electronic device substrates; or other oxide layers can be deposited on the substrate in advance, but another component will be introduced, greatly increasing the complexity of process design and equipment.

[0003] The hydrophobicity of HMDSO film mainly comes from the methyl (CH3) functional group. In the HMDSO molecule, there are three methyl groups (-CH3) around each silicon atom. These methyl groups make the film hydrophobic. However, since the methyl group is a non-polar group, it also shows a weak interaction with the substrate. HMDSO also contains oxygen elements. By adjusting the process parameters, it can generate oxygen-rich SiO with a low carbon-oxygen ratio. x C y It can show better bonding ability with the substrate, but will lose its hydrophobicity due to the decrease of its carbon content. Summary of the invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for adjusting the carbon-oxygen ratio of a thin film and a hydrophobic film layer.

[0005] The present invention provides a method for adjusting the carbon-oxygen ratio of a thin film, comprising the following steps:

[0006] The substrate is placed in a reaction chamber, and an organosiloxane monomer source and an inert gas are introduced to perform plasma chemical vapor deposition. During the deposition process, the concentration of the organosiloxane monomer source in the reaction chamber changes and / or the discharge power changes to obtain a coated substrate.

[0007] In an optional embodiment, the change includes one or more of linear continuous increase, linear continuous decrease, nonlinear continuous increase, nonlinear continuous decrease, staged increase and staged decrease;

[0008] And / or, the organosiloxane monomer source is selected from one or more of hexamethyldisiloxane, tetramethyldisiloxane and tetraethylsiloxane.

[0009] In an optional embodiment, the organosiloxane monomer source is introduced into the reaction chamber through a source-carrying gas; the source-carrying gas includes the organosiloxane monomer source and an inert gas; the inert gas in the reaction chamber includes the inert gas in the source-carrying gas, or includes the inert gas in the source-carrying gas and the straight-through inert gas;

[0010] The concentration of the organosiloxane monomer source in the reaction chamber is the ratio of the organosilane monomer source to the sum of the organosilane monomer source and the inert gas in the reaction chamber;

[0011] The concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the source-carrying gas introduced during the deposition process;

[0012] And / or, the concentration of the organosiloxane monomer source in the reaction chamber is changed by adjusting the temperature of the source-carrying gas introduced during the deposition process;

[0013] And / or, the concentration of the organosiloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the straight-through inert gas during the deposition process.

[0014] In an alternative embodiment, the source-carrying gas is formed by passing an inert gas through a source of organosiloxane monomer;

[0015] When the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the source-carrying gas introduced during the deposition process, the flow rate of the inert gas in the source-carrying gas varies within the range of 50 to 1000 sccm, and the flow rate of the fixed straight-through inert gas is 0 to 1500 sccm;

[0016] When the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the temperature change of the source-carrying gas introduced during the deposition process, it is achieved by adjusting the temperature of the organic siloxane monomer source through which the inert gas passes during the deposition process, and / or, it is achieved by adjusting the temperature of the inert gas passing through the organic siloxane monomer source; the temperature of the organic siloxane monomer source varies within the range of 15°C to 50°C; the temperature of the inert gas passing through the organic siloxane monomer source varies within the range of 15°C to 50°C;

[0017] When the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the straight-through gas during the deposition process, the flow rate of the straight-through inert gas varies within the range of 200 to 1500 sccm, and the flow rate of the inert gas in the fixed source-carrying gas is 50 to 1000 sccm;

[0018] And / or, the discharge power during the deposition process varies within the range of 100 to 1000 W.

[0019] In an optional embodiment, when the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the source-carrying gas introduced during the deposition process, the flow rate of the inert gas in the source-carrying gas is changed at a rate of 5 to 50 sccm / min;

[0020] and / or, when the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the straight-through inert gas during the deposition process, the change rate of the flow rate of the straight-through inert gas is 5 to 50 sccm / min;

[0021] And / or, the rate of change of discharge power during the deposition process is 5 to 30 W / min.

[0022] In an optional embodiment, the flow rate of the inert gas is 250 to 1200 sccm;

[0023] And / or, the temperature of the plasma chemical vapor deposition is 20°C to 50°C;

[0024] And / or, the plasma chemical vapor deposition time is 10 to 30 minutes.

[0025] In an optional embodiment, the concentration of the organosiloxane monomer source in the reaction chamber increases continuously during the deposition process;

[0026] The concentration of the organic siloxane monomer source in the reaction chamber is increased by reducing the flow rate of the straight-through inert gas during the deposition process, and the flow rate reduction rate of the straight-through inert gas is 5 to 50 sccm / min;

[0027] And / or, the discharge power gradually decreases during the deposition process, with a decrease rate of 5 to 30 W / min.

[0028] In an optional embodiment, the concentration of the organic siloxane monomer source in the reaction chamber is increased by reducing the flow rate of the straight-through inert gas during the deposition process, wherein the initial flow rate of the straight-through inert gas is 1500 to 800 sccm, and the flow rate of the straight-through inert gas is gradually reduced to 600 to 200 sccm during the deposition process, and the flow rate reduction rate of the straight-through inert gas is 10 to 30 sccm / min;

[0029] And / or, the initial discharge power of the plasma chemical vapor deposition is 400-1000W, and the discharge power gradually decreases to 100-400W during the deposition process; the reduction rate of the discharge power is 10-20W / min.

[0030] In an optional embodiment, the substrate is placed in the reaction chamber after being pre-treated; the pre-treatment includes: cleaning and plasma surface treatment;

[0031] The gases for plasma surface treatment are argon and oxygen;

[0032] The argon-oxygen ratio of the plasma surface treatment is 1 to 0.2:1;

[0033] And / or, the discharge power of the plasma surface treatment is 200 to 500 W;

[0034] And / or, the plasma surface treatment time is 2 to 10 minutes.

[0035] The present invention also provides a hydrophobic film layer prepared by the above method.

[0036] In an optional embodiment, the hydrophobic film layer includes element Si, element C and element O; the carbon-oxygen ratio of the bottom of the hydrophobic film layer is (0.2-2.5):(0.7-2.3); the carbon-oxygen ratio of the surface layer of the hydrophobic film layer is (1.6-2.7):(0.5-1).

[0037] The present invention provides a method for adjusting the carbon-oxygen ratio of a thin film, comprising the following steps: placing a substrate in a reaction chamber, introducing an organic siloxane monomer source and an inert gas to perform plasma chemical vapor deposition, and during the deposition process, the concentration of the organic siloxane monomer source in the reaction chamber changes and / or the discharge power changes, to obtain a film-coated substrate. Compared with the prior art, the present invention can achieve the effect of adjusting the carbon-oxygen ratio of a thin film by only adjusting the concentration change of the organic siloxane monomer source in the reaction chamber and / or the discharge power change, the method is simple and easy to implement, and can achieve continuous adjustment.

[0038] Furthermore, the present invention adjusts the carbon-oxygen ratio so that the bottom of the film layer is an oxygen-rich structure with good adhesion to the substrate, and the top of the film layer is a carbon-rich component with good hydrophobicity, thereby solving the problem of the bonding strength between the film layer and the substrate and also having good hydrophobicity.

[0039] Furthermore, the present invention can achieve a continuously adjustable carbon-oxygen ratio in the film layer to obtain a gradual film layer structure, thereby achieving the purpose of no film layer interface existing inside the hydrophobic film.

[0040] Furthermore, the present invention can achieve continuous adjustment of the carbon-oxygen ratio of the film layer, so that the bottom of the film layer is an oxygen-rich structure with good adhesion to the substrate, the top of the film layer is a carbon-rich component with good hydrophobicity, the composition of the film layer changes continuously from bottom to top, the carbon-oxygen ratio gradually increases continuously, and there is no film layer interface inside the hydrophobic film, thereby achieving the premise of enhancing the adhesion of the film layer to the substrate and ensuring the hydrophobicity of the top of the film layer without introducing other oxide layers.

[0041] Furthermore, the present invention can further enhance the bonding force between the substrate and the coating by performing plasma treatment on the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of the change of gas flow rate during the plasma chemical vapor deposition process of the present invention;

[0043] Figure 2 A schematic diagram of the change of carbon and oxygen content in the hydrophobic film layer provided by the present invention;

[0044] Figure 3 is a graph showing the relationship between discharge power and contact angle in Example 1 of the present invention;

[0045] Figure 4 Graph showing the bonding strength test results of the films obtained in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0046] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0047] The present invention provides a method for adjusting the carbon-oxygen ratio of a thin film, comprising the following steps: placing a substrate in a reaction chamber, introducing an organic siloxane monomer source and an inert gas to perform plasma chemical vapor deposition, and during the deposition process, the concentration of the organic siloxane monomer source in the reaction chamber changes and / or the discharge power changes, to obtain a film-coated substrate.

[0048] The present invention has no particular limitation on the sources of all raw materials, and any raw materials available on the market can be used.

[0049] In the present invention, the substrate can be any substrate well known to those skilled in the art without any special limitation, including but not limited to a PET substrate, a glass substrate, and a metal substrate.

[0050] In a specific embodiment provided by the present invention, the substrate is preferably placed in the reaction chamber after pretreatment; the pretreatment includes: cleaning and plasma surface treatment; the cleaning is preferably carried out using anhydrous ethanol and deionized water; the cleaning method is preferably ultrasonic cleaning; the cleaning time is preferably 5 to 10 minutes; the gas for the plasma surface treatment is preferably argon and oxygen; the argon-oxygen ratio of the plasma surface treatment is preferably 1 to 0.2:1, more preferably 1 to 0.5:1, more preferably 1 to 0.8:1, and most preferably 1:1; the discharge power of the plasma surface treatment is preferably 200 to 500W, more preferably 300 to 500W, and more preferably 400W; the plasma surface treatment time is preferably 2 to 10 minutes, more preferably 4 to 8 minutes, and more preferably 5 minutes. Pretreatment can remove organic / inorganic pollutants on the substrate surface while making the substrate surface have dangling oxygen bonds, and also help to form O-Si bonds with siloxane monomers, further enhancing the adhesion of the coating to the substrate.

[0051] In a specific embodiment provided by the present invention, the pretreated substrate is placed in a reaction chamber, and an organosiloxane monomer source and an inert gas are introduced to perform plasma chemical vapor deposition, and during the deposition process, the concentration of the organosiloxane monomer source in the reaction chamber changes and / or the discharge power changes, to obtain a coated substrate.

[0052] In a specific embodiment provided by the present invention, the pretreated substrate is placed in a reaction chamber, preferably evacuated, and an organosiloxane monomer source and an inert gas are introduced for plasma chemical vapor deposition; the organosiloxane monomer source can be an organosiloxane monomer source well known to those skilled in the art, without any special restrictions, and in the present invention can specifically be one or more of hexamethyldisiloxane, tetramethyldisiloxane and tetraethylsiloxane; the inert gas can be an inert gas well known to those skilled in the art, without any special restrictions, and in the present invention, argon and / or helium are preferred.

[0053] In a specific embodiment provided by the present invention, the flow rate of the inert gas is preferably 250 to 1200 sccm; the temperature of the plasma chemical vapor deposition is preferably 20°C to 50°C, more preferably 20°C to 40°C, and even more preferably 20°C to 30°C; the time of the plasma chemical vapor deposition is preferably 10 to 30 min, more preferably 10 to 20 min.

[0054] During the deposition process, the concentration of the organosiloxane monomer source in the reaction chamber changes and / or the discharge power changes; in the present invention, the concentration of the organosiloxane monomer source in the reaction chamber refers to the ratio of the organosilane monomer source to the sum of the organosilane monomer source and the inert gas in the reaction chamber; in the present invention, the change specifically includes one or more of linear continuous increase, linear continuous decrease, nonlinear continuous increase, nonlinear continuous decrease, staged increase and staged decrease. Plasma discharge ionizes the mixed vapor of the inert gas and the organosiloxane monomer source, and the chemical bonds of the organosiloxane monomer source are broken and reorganized, eventually forming SiO x C y The hydrophobic film is mainly composed of residual methyl -CH3, and the hydrophobicity comes from residual methyl -CH3. During the deposition process, when the concentration of the organosiloxane monomer source in the reaction chamber increases, the oxygen content in the deposited film is low and the carbon content is high, while when the concentration of the organosiloxane monomer source in the reaction chamber decreases, the oxygen content in the deposited film is high and the carbon content is low, thereby achieving an adjustable carbon-oxygen ratio in the film; when the discharge power is high, the chemical source dissociates sufficiently, and the C element will tend to dissociate into the atmosphere of the chamber and be removed from the reaction chamber by vacuum, so that the C content deposited in the film is relatively low; when the discharge power is reduced, the dissociation of the organosiloxane monomer source will decrease, and the retained methyl component will increase, thereby increasing the C content in the deposited film, thereby achieving an adjustable carbon-oxygen ratio in the film.

[0055] In a specific embodiment provided by the present invention, the organosiloxane monomer source is introduced into the reaction chamber through a source-carrying gas; the source-carrying gas includes an organosiloxane monomer source and an inert gas; the inert gas in the reaction chamber includes an inert gas in the source-carrying gas, or includes an inert gas in the source-carrying gas and a directly passed inert gas.

[0056] In a specific embodiment provided by the present invention, the change in the concentration of the organosiloxane monomer source in the reaction chamber can be achieved by adjusting the flow rate change of the source-carrying gas introduced during the deposition process; specifically, the source-carrying gas is formed by passing an inert gas through the organosiloxane monomer source, that is, passing an inert gas through the liquid of the organosiloxane monomer source, during which the liquid of the organosiloxane monomer source is volatilized into a gas to form the source-carrying gas carried by the inert gas; the concentration of the organosiloxane monomer source in the source-carrying gas is correlated with the flow rate of the inert gas in the source-carrying gas and the temperature of the organosiloxane monomer source. The temperature of the organosiloxane monomer source is affected by the set temperature of the organosiloxane monomer source and the temperature of the inert gas introduced into the organosiloxane monomer source. A high temperature of the inert gas introduced into the organosiloxane monomer source or a high set temperature of the organosiloxane monomer source will cause the organosiloxane monomer source to volatilize more organosiloxane monomers, and a high flow rate of the inert gas introduced into the organosiloxane monomer source will cause a larger amount of the organosiloxane monomer source carried per unit time. However, the incremental amount of organosiloxane carried out by the source-carrying inert gas is smaller than the incremental amount of the increased source-carrying inert gas. That is to say, under the same temperature conditions, only increasing the flow rate of the inert gas introduced into the organosiloxane monomer source will increase the amount of organosiloxane monomer carried per unit time, but will reduce the proportion of the organosiloxane monomer in the sum of the inert gas and the organosiloxane monomer source mixed gas, that is, will reduce the concentration of the organosiloxane monomer. Therefore, when the flow rate of the inert gas introduced into the organosiloxane monomer source increases, the temperature of the organosiloxane monomer source decreases, or the temperature of the inert gas introduced into the organosiloxane monomer source decreases, the concentration of the organosiloxane monomer source in the entire source-carrying gas decreases; when the flow rate of the inert gas introduced into the organosiloxane monomer source decreases, the temperature of the organosiloxane monomer source increases, or the temperature of the inert gas introduced into the organosiloxane monomer source increases, the concentration of the organosiloxane monomer source in the entire source-carrying gas increases. It can be understood that when the concentration of the organosiloxane monomer source is regulated by the source-carrying gas, it is necessary to coordinately regulate the temperature of the organosiloxane monomer source, the flow rate of the inert gas introduced into the organosiloxane monomer source, and the temperature.

[0057] In a specific embodiment provided by the present invention, during the deposition process, when the flow rate of the source-carrying gas changes, a straight-through inert gas can be introduced at the same time, and the flow rate of the straight-through inert gas remains fixed; or the concentration of the organic siloxane monomer source in the reaction chamber can be adjusted only by the flow rate, temperature, and temperature of the source-carrying gas without introducing a straight-through inert gas; further specifically, the flow rate of the inert gas in the source-carrying gas varies in the range of 50 to 1000 sccm, and the flow rate of the fixed straight-through gas is 0 to 1500 sccm; further specifically, the flow rate of the inert gas in the source-carrying gas preferably varies in the range of 50 to 800 sccm, and more preferably in the range of 50 to 800 sccm. Preferably, the flow rate of the inert gas in the source-carrying gas varies in the range of 0 to 600 sccm, preferably in the range of 50 to 500 sccm, more preferably in the range of 50 to 300 sccm, and most preferably in the range of 50 to 200 sccm; more specifically, when the flow rate of the inert gas in the source-carrying gas varies, the flow rate of the fixed straight-through inert gas is 0 to 1200 sccm, preferably 100 to 1200 sccm, more preferably 200 to 1200 sccm, more preferably 300 to 1100 sccm, more preferably 400 to 1000 sccm, more preferably 500 to 900 sccm, and most preferably 600 to 800 sccm.

[0058] In a specific embodiment provided by the present invention, the change rate of the flow rate of the inert gas in the source-carrying gas is preferably 5-50 sccm / min, more preferably 5-40 sccm / min, further preferably 10-40 sccm / min, further preferably 10-30 sccm / min, and most preferably 20 sccm / min.

[0059] In a specific embodiment provided by the present invention, the concentration of the organic siloxane monomer source in the reaction chamber can be changed by adjusting the temperature change of the source-carrying gas introduced during the deposition process; specifically, it can be achieved by adjusting the temperature of the organic siloxane monomer source through which the inert gas passes during the deposition process, and / or, by adjusting the temperature of the inert gas passing through the organic siloxane monomer source; the volatilization amount of the organic siloxane monomer source can be adjusted by adjusting the temperature of the inert gas and / or the temperature of the organic siloxane monomer source, thereby adjusting the content of the organic siloxane monomer source in the source-carrying gas; when the temperature of the inert gas and / or the temperature of the organic siloxane monomer source is high, the volatilization amount of the organic siloxane monomer source is high, Thereby, the content of the organosiloxane monomer source in the source-carrying gas is increased. When the temperature of the inert gas and / or the temperature of the organosiloxane monomer source is low, the volatilization amount of the organosiloxane monomer source is low, thereby reducing the content of the organosiloxane monomer source in the source-carrying gas; more specifically, the temperature of the organosiloxane monomer source preferably varies in the range of 15°C to 50°C, more preferably in the range of 15°C to 40°C, and more preferably in the range of 20°C to 40°C; more specifically, the temperature of the inert gas passing through the organosiloxane monomer source preferably varies in the range of 15°C to 50°C, more preferably in the range of 15°C to 40°C, and more preferably in the range of 20°C to 40°C.

[0060] In a specific embodiment provided by the present invention, the concentration of the organosiloxane monomer source in the reaction chamber changes linearly; specifically, the temperature change rate of the inert gas passing through the organosiloxane monomer source is preferably 1 to 10°C / min, more preferably 1 to 5°C / min; specifically, the temperature change rate of the organosiloxane monomer source is preferably 1 to 10°C / min, more preferably 1 to 5°C / min.

[0061] In another specific embodiment provided by the present invention, the concentration of the organosiloxane monomer source in the reaction chamber continuously increases during the deposition process; specifically, the temperature increase rate of the inert gas passing through the organosiloxane monomer source is preferably 1 to 10°C / min, more preferably 1 to 5°C / min; specifically, the temperature increase rate of the organosiloxane monomer source is preferably 1 to 10°C / min, more preferably 1 to 5°C / min.

[0062] In a specific embodiment provided by the present invention, the change in the concentration of the organic siloxane monomer source in the reaction chamber is achieved by adjusting the flow change of the straight-through inert gas during the deposition process; when the flow change of the straight-through inert gas increases, the amount of inert gas in the reaction chamber increases, thereby reducing the concentration of the organic siloxane monomer source; when the flow change of the straight-through inert gas decreases, the amount of inert gas in the reaction chamber decreases, thereby increasing the concentration of the organic siloxane monomer source; in this process, the flow rate of the source-carrying gas may be fixed or may change. Preferably, the flow rate of the inert gas in the source-carrying gas remains unchanged. See Figure 1 and Figure 2 , Figure 1 Schematic diagram of gas flow rate change during plasma chemical vapor deposition. Figure 2 It is a schematic diagram of the change of carbon and oxygen content in the hydrophobic film layer; specifically, the flow rate of the straight-through inert gas varies in the range of 200-1500sccm, and the flow rate of the inert gas in the fixed source-carrying gas is 50-1000sccm; more specifically, the flow rate of the straight-through inert gas preferably varies in the range of 200-1300sccm, more preferably in the range of 300-1200sccm, more preferably in the range of 400-1100sccm, more preferably in the range of 400-1000sccm, most preferably in the range of 600-800sccm; more specifically, the flow rate of the inert gas in the fixed source-carrying gas is preferably 50-1000sccm, more preferably 50-800sccm, more preferably 50-600sccm, more preferably 50-400sccm, more preferably 50-200sccm, and most preferably 50-100sccm.

[0063] In a specific embodiment provided by the present invention, the concentration of the organosiloxane monomer source in the reaction chamber changes linearly; specifically, the change rate of the flow rate of the straight-through inert gas is preferably 5-50 sccm / min, more preferably 5-40 sccm / min, more preferably 10-40 sccm / min, more preferably 10-30 sccm / min, and most preferably 20 sccm / min.

[0064] In another specific embodiment provided by the present invention, the concentration of the organosiloxane monomer source in the reaction chamber continuously increases during the deposition process; specifically, the rate of decrease of the flow rate of the straight-through inert gas is preferably 5 to 50 sccm / min, more preferably 5 to 40 sccm / min, further preferably 10 to 40 sccm / min, further preferably 10 to 30 sccm / min, and most preferably 20 sccm / min.

[0065] In another specific embodiment provided by the present invention, the concentration of the organic siloxane monomer source in the reaction chamber is increased by reducing the flow rate of the straight-through inert gas during the deposition process, the initial flow rate of the straight-through inert gas is 1500-800 sccm, and the flow rate of the straight-through inert gas is gradually reduced to 600-200 sccm during the deposition process, and the flow rate reduction rate of the straight-through inert gas is 10-30 sccm / min; specifically, the initial flow rate of the straight-through inert gas is preferably 1500-800 sccm. cm, more preferably 1200-800sccm, and even more preferably 1000-800sccm; specifically, during the deposition process, the flow rate of the straight-through inert gas is preferably gradually reduced to 600-200sccm, more preferably gradually reduced to 600-400sccm, and even more preferably gradually reduced to 600-500sccm; specifically, the flow rate reduction rate of the straight-through inert gas is preferably 10-30sccm / min, more preferably 15-25sccm / min, and even more preferably 20sccm / min.

[0066] In a specific embodiment provided by the present invention, the discharge power in the deposition process preferably varies in the range of 100 to 1000 W, more preferably in the range of 100 to 800 W, more preferably in the range of 200 to 800 W, more preferably in the range of 300 to 700 W, more preferably in the range of 350 to 650 W, and most preferably in the range of 350 to 500 W.

[0067] In a specific embodiment provided by the present invention, the change in discharge power during the deposition process is a linear change; specifically, the rate of change of discharge power during the deposition process is preferably 5 to 30 W / min, more preferably 10 to 25 W / min, further preferably 10 to 20 W / min, and most preferably 15 W / min.

[0068] In a specific embodiment provided by the present invention, the change in discharge power gradually decreases during the deposition process; specifically, the rate of decrease of discharge power during the deposition process is preferably 5 to 30 W / min, more preferably 10 to 25 W / min, further preferably 10 to 20 W / min, and most preferably 15 W / min.

[0069] In another specific embodiment provided by the present invention, the initial discharge power of the plasma chemical vapor deposition is 400-1000W, and the discharge power gradually decreases to 100-400W during the deposition process; the rate of decrease of the discharge power is 10-20W / min; specifically, the initial discharge power of the plasma chemical vapor deposition is preferably 400-800W, more preferably 400-700W, more preferably 400-600W, more preferably 450-550W, and most preferably 500W; specifically, during the deposition process, the discharge power is preferably gradually reduced to 150-400W, more preferably gradually reduced to 200-400W, more preferably gradually reduced to 250-400W, more preferably gradually reduced to 300-400W, and most preferably gradually reduced to 350W; specifically, the rate of decrease of the discharge power is preferably 15W / min.

[0070] In the present invention, one or more of the above changes can be selected without special restrictions. When the concentration of the organosiloxane monomer source in the reaction chamber is low or the discharge power is high, the chemical source is fully dissociated, and the C element will tend to dissociate and be withdrawn from the chamber. The C content deposited in the film is low, the hydrophobicity is low, but the binding force with the substrate is high. By increasing the concentration of the organosiloxane monomer source in the reaction chamber or reducing the discharge power, the dissociation of the organosiloxane monomer source will be reduced, the retained methyl component will increase, the C content deposited in the film will increase, and the hydrophobicity will increase.

[0071] In another specific embodiment provided by the present invention, during the plasma chemical vapor deposition process, the concentration of the organosiloxane monomer source in the reaction chamber gradually increases while the discharge power gradually decreases, thereby adjusting the source dissociation rate and increasing the carbon content of the film layer.

[0072] The present invention realizes continuous adjustment of the carbon-oxygen ratio of the film layer by continuously changing the atmosphere and / or discharge power of the plasma process chamber along with the deposition process time, further making the bottom of the film layer an oxygen-rich structure with good adhesion to the substrate, and the top of the film layer a carbon-rich component with good hydrophobicity. The composition of the film layer changes continuously from bottom to top, and the carbon-oxygen ratio gradually and continuously increases. There is no film layer interface inside the hydrophobic film, thereby achieving the advantages of enhancing the adhesion of the film layer to the substrate and ensuring the hydrophobicity of the top of the film layer without introducing other oxide layers.

[0073] The present invention also provides a hydrophobic film layer, which is prepared by the above method capable of adjusting the carbon-oxygen ratio of the film.

[0074] In a specific embodiment provided by the present invention, the hydrophobic film layer includes element Si, element C and element O; the carbon-oxygen ratio of the bottom of the hydrophobic film layer is (0.2-2.5): (0.7-2.3); the carbon-oxygen ratio of the bottom is preferably (0.4-2.4): (0.8-2.2); the carbon-oxygen ratio of the bottom is preferably (0.7-2.2): (0.9-2.2); the carbon-oxygen ratio of the surface layer of the hydrophobic film layer is (1.6-2.7): (0.5-1), and the carbon-oxygen ratio of the top layer is preferably (1.7-2.4): (0.6-0.95); the carbon-oxygen ratio of the top layer is preferably (1.8-2.3): (0.65-0.9). The relative change of the carbon-oxygen ratio, the difference in hydrophilicity and hydrophobicity, and the difference in substrate binding performance between the surface and bottom layers of the same hydrophobic film layer are sufficient, and the specific definition range of the carbon-oxygen ratio of the top layer and the surface layer of different hydrophobic film layers is not limited. Because the carbon-oxygen ratios of the films prepared by different precursor sources are different, the surface layers prepared by different precursor sources may have the same or similar carbon-oxygen ratios as the top layers prepared by other precursor sources. Therefore, there is an overlap in the carbon-oxygen ratios of the surface layer and the top layer. The purpose of this solution is to achieve regulation of the carbon-oxygen ratios of the top layer and the surface layer and the part between the top layer and the surface layer in the film layer under the current film layer performance and preparation conditions during the specific implementation and application process, thereby regulating the substrate bonding force of the film layer and the hydrophobicity of the surface layer, without giving a specific range for a specific preparation process.

[0075] In another specific embodiment provided by the present invention, the carbon-oxygen ratio in the hydrophobic film layer increases continuously from the bottom to the surface.

[0076] In order to further illustrate the present invention, a method for adjusting the carbon-oxygen ratio of a thin film and a hydrophobic film layer provided by the present invention are described in detail below in conjunction with embodiments.

[0077] The reagents used in the following examples are all commercially available.

[0078] Example 1

[0079] 1.1 The glass substrate to be coated was ultrasonically cleaned with anhydrous ethanol and deionized water for 5 minutes to remove organic / inorganic pollutants on the surface. It was also pretreated with oxygen plasma (Ar / O ratio of 1, discharge power of 400W, time of 5 minutes).

[0080] 1.2 Place the pretreated glass substrate to be coated into the PECVD process chamber and evacuate the chamber; the chamber temperature is 20°C.

[0081] 1.3 The HMDSO chemical source was introduced by Ar source carrying method, with a source flow rate of 50 sccm, an initial straight argon starting flow rate of 750 sccm, a plasma discharge power of 500 W, and a discharge power decrease rate of 15 W / min.

[0082] 1.4 During the deposition process, gradually reduce the straight-through argon gas flow rate to 600 sccm, reduce the rate to 15 sccm / min, and the deposition time is 10 min.

[0083] 1.5 After the process is completed, the carbon-oxygen ratio of the surface and deep layer of the film is tested by XPS.

[0084] A single factor experiment was conducted according to the conditions of Example 1, with regard to the effect of the straight-through argon gas flow rate on the carbon-oxygen ratio, and the specific conditions were as follows:

[0085] (1) The straight-through argon gas flow rate is maintained at 600 sccm (corresponding to the surface layer in Table 1);

[0086] (2) The straight-through argon gas flow rate is maintained at 750 sccm (corresponding to the bottom layer in Table 2);

[0087] Table 1 Straight-through argon flow single factor film carbon-oxygen ratio test results

[0088]

[0089]

[0090] It can be seen from Table 1 that the carbon-oxygen ratio in the surface layer is 1.96:0.74, and the carbon-oxygen ratio in the bottom layer is 2.26:0.98. It can be seen that the increase in the flow rate of the DC inert gas reduces the concentration of the HMDSO chemical source in the plasma reaction chamber, and the carbon-oxygen ratio in the deposited film layer becomes smaller. The smaller the carbon-oxygen ratio, the higher the bonding force between the film layer and the substrate, and the larger the carbon-oxygen ratio, the higher the hydrophobicity of the film layer.

[0091] A single factor experiment was conducted according to the conditions of Example 1, with regard to the effect of plasma discharge power on the carbon-oxygen ratio. The specific conditions are as follows:

[0092] The straight-through argon gas flow rate is kept constant at 600 sccm, and different discharge powers (constant) are used, 200 W, 500 W and 1000 W, respectively. The carbon-oxygen ratio of the film is shown in Table 2, and the relationship between the discharge power and the contact angle is shown in Table 2. Figure 3 shown.

[0093] Table 2 Discharge power single factor film carbon oxygen ratio test results

[0094]

[0095]

[0096] It can be seen from Table 2 that when the discharge power is 200W, the carbon-oxygen ratio of the film is 2.13:0.55, when the discharge power is 500W, the carbon-oxygen ratio of the film is 1.96:0.74, and when the discharge power is 1000W, the carbon-oxygen ratio of the film is 0.78:1.97. It can be seen that in the process of changing from 200W to 500W, when the discharge power is higher, the carbon-oxygen ratio of the film is lower, and when the discharge power is lower, the carbon-oxygen ratio of the film is higher. When the discharge power is further increased to 1000W, the oxygen content even exceeds the carbon content, and the carbon-oxygen ratio is further reduced. At the same time, Figure 3 It can be seen that when the discharge power is low, the film layer has a higher hydrophobicity. When the discharge power is high, the hydrophobicity decreases, but at this time the film layer has a better substrate bonding force.

[0097] Example 2

[0098] The conditions of Example 1 were followed, except that HMDSO was replaced with TMDSO. After the process, the carbon-oxygen ratios of the surface and deep layers of the film were tested by XPS. The carbon-oxygen ratios of the surface layer were 1.63:0.80, and the carbon-oxygen ratios of the bottom layer were 1.71:0.92, indicating that the film had a higher carbon-oxygen ratio and better hydrophobicity when the through argon flow rate was low and the discharge power was low.

[0099] Example 3

[0100] The conditions of Example 1 were followed, except that HMDSO was changed to TEOS; after the process was completed, the carbon-oxygen ratio of the surface and deep layers of the film was tested by XPS, and the carbon-oxygen ratio of the surface layer was 2.05:2.32, and the carbon-oxygen ratio of the bottom layer was 1.78:2.02, which resulted in a higher carbon-oxygen ratio when the straight-through argon flow rate was low and the discharge power was low, but the hydrophobicity was poor. This is because the TEOS precursor has a high oxygen content, resulting in poor hydrophobicity of the prepared film layer. According to the comparison of the data, it can be seen that the carbon-oxygen ratio of the film layer can also be regulated when the straight-through flow rate is low and the discharge power is low.

[0101] Example 4

[0102] The deposition process was carried out under the conditions of Example 1. While reducing the straight argon flow rate, the plasma discharge power was gradually reduced to 200 W. After the process was completed, the carbon-oxygen ratio of the surface and deep layer of the film was tested by XPS. The carbon-oxygen ratio of the surface layer was 2.08:0.53, and the carbon-oxygen ratio of the bottom layer was 2.26:0.98. It was found that the surface of the film had a higher carbon-oxygen ratio, while the deep layer had a lower carbon-oxygen ratio and a higher substrate bonding force than the surface.

[0103] Example 5

[0104] The conditions of Example 1 were followed, with a plasma discharge power of 800 W. During the deposition process, the through argon flow rate was reduced while the plasma discharge power was gradually reduced to 200 W. After the process, the carbon-oxygen ratios of the surface and deep layers of the film were tested by XPS. The carbon-oxygen ratios of the surface layer were 1.94:0.55, and the carbon-oxygen ratios of the bottom layer were 1.52:1.31. The film surface had a higher carbon-oxygen ratio, while the deep layer had a lower carbon-oxygen ratio and a higher substrate bonding force relative to the surface.

[0105] Example 6

[0106] The conditions of Example 1 were followed, and the temperature of the organosiloxane monomer source was 45°C. After the process was completed, the carbon-oxygen ratio of the surface and deep layers of the film was tested by XPS. The carbon-oxygen ratio of the surface layer was 2.61:0.92, and the carbon-oxygen ratio of the bottom layer was 2.11:0.82, which showed that the surface of the film had a higher carbon-oxygen ratio, while the deep layer had a lower carbon-oxygen ratio relative to the surface. The high temperature of the organosiloxane monomer source can increase the concentration of the source, and the carbon-oxygen ratio is increased relative to Example 1.

[0107] Example 7

[0108] According to the conditions of Example 1, the temperature of the organosiloxane monomer source is 45°C, and the plasma discharge power is gradually reduced to 200W while reducing the straight argon flow rate during the deposition process; after the process, the carbon-oxygen ratio of the surface and deep layer of the film is tested by XPS, and the carbon-oxygen ratio of the surface layer is 2.35:0.58, and the carbon-oxygen ratio of the bottom layer is 1.98:0.76, which shows that the surface of the film has a higher carbon-oxygen ratio, while the deep layer has a lower carbon-oxygen ratio relative to the surface. The high temperature of the organosiloxane monomer source can increase the concentration of the source, and the carbon-oxygen ratio is increased relative to Example 1.

[0109] Comparative Example 1

[0110] 1.1 The glass substrate to be coated was ultrasonically cleaned with anhydrous ethanol and deionized water for 5 minutes to remove organic / inorganic pollutants on the surface. It was also pretreated with oxygen plasma (Ar / O ratio of 1, discharge power of 400W, time of 5 minutes).

[0111] 1.2 Place the pretreated glass substrate to be coated into the PECVD process chamber and evacuate the chamber; the chamber temperature is 20°C.

[0112] 1.3 The HMDSO chemical source was introduced by Ar source carrying method, with a source flow rate of 50 sccm. The initial straight argon starting flow rate was 600 sccm and remained unchanged during the deposition process. The plasma discharge power was 500 W and the deposition time was 10 min.

[0113] After the process is completed, the alcohol friction test (100g weight alcohol dust-free cloth wipe 50 times) is carried out to verify the bonding test results. Figure 4 As shown, the left figure is Example 1, and the right figure is Comparative Example 1. Figure 4 It can be seen that the film obtained in Example 1 shows better adhesion and wear resistance before and after rubbing, and the hydrophobic properties before and after are maintained. It can be seen from the film obtained in Comparative Example 1 before and after rubbing that the surface coating has partially fallen off, and the hydrophobicity before and after is reduced. It can be seen that although the film obtained in Comparative Example 1 has a higher hydrophobicity at the beginning, the coating is easy to fall off due to the low bonding force between the coating and the substrate, while the coating obtained in Example 1 has a lower carbon-oxygen ratio in the bottom layer. Although the hydrophobicity is low, it has a high bonding force with the substrate, and the surface has a higher carbon-oxygen ratio and higher hydrophobicity, so that the coating has a higher hydrophobicity on the basis of good bonding with the substrate, and the carbon-oxygen ratio in the coating changes continuously, and the coating itself also has a higher wear resistance.

[0114] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for adjusting the carbon-oxygen ratio of a thin film, characterized in that: The following steps are involved: The substrate is placed in a reaction chamber, and an organosiloxane monomer source and an inert gas are introduced to perform plasma chemical vapor deposition. During the deposition process, the concentration of the organosiloxane monomer source in the reaction chamber changes and / or the discharge power changes to obtain a coated substrate.

2. The method according to claim 1, characterized in that The change includes one or more of linear continuous increase, linear continuous decrease, nonlinear continuous increase, nonlinear continuous decrease, staged increase and staged decrease; And / or, the organosiloxane monomer source is selected from one or more of hexamethyldisiloxane, tetramethyldisiloxane and tetraethylsiloxane.

3. The method according to claim 1, characterized in that The organosiloxane monomer source is introduced into the reaction chamber through a source-carrying gas; the source-carrying gas includes the organosiloxane monomer source and an inert gas; the inert gas in the reaction chamber includes the inert gas in the source-carrying gas, or includes the inert gas in the source-carrying gas and the straight-through inert gas; The concentration of the organosiloxane monomer source in the reaction chamber is the ratio of the organosilane monomer source to the sum of the organosilane monomer source and the inert gas in the reaction chamber; The concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the source-carrying gas introduced during the deposition process; And / or, the concentration of the organosiloxane monomer source in the reaction chamber is changed by adjusting the temperature of the source-carrying gas introduced during the deposition process; And / or, the concentration of the organosiloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the straight-through inert gas during the deposition process.

4. The method according to claim 3, characterized in that The source-carrying gas is formed by passing an inert gas through a source of an organosiloxane monomer; When the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the source-carrying gas introduced during the deposition process, the flow rate of the inert gas in the source-carrying gas varies within the range of 50 to 1000 sccm, and the flow rate of the fixed straight-through inert gas is 0 to 1500 sccm; When the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the temperature change of the source-carrying gas introduced during the deposition process, it is achieved by adjusting the temperature of the organic siloxane monomer source through which the inert gas passes during the deposition process, and / or, it is achieved by adjusting the temperature of the inert gas passing through the organic siloxane monomer source; the temperature of the organic siloxane monomer source varies within the range of 15°C to 50°C; the temperature of the inert gas passing through the organic siloxane monomer source varies within the range of 15°C to 50°C; When the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the straight-through gas during the deposition process, the flow rate of the straight-through inert gas varies within the range of 200 to 1500 sccm, and the flow rate of the inert gas in the fixed source-carrying gas is 50 to 1000 sccm; And / or, the discharge power during the deposition process varies within the range of 100 to 1000 W.

5. The method according to claim 4, characterized in that When the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the source-carrying gas introduced during the deposition process, the flow rate of the inert gas in the source-carrying gas is changed at a rate of 5 to 50 sccm / min; and / or, when the concentration of the organic siloxane monomer source in the reaction chamber is changed by adjusting the flow rate of the straight-through inert gas during the deposition process, the change rate of the flow rate of the straight-through inert gas is 5 to 50 sccm / min; And / or, the rate of change of discharge power during the deposition process is 5 to 30 W / min.

6. The method according to claim 1, characterized in that The flow rate of the inert gas is 250 to 1200 sccm; And / or, the temperature of the plasma chemical vapor deposition is 20°C to 50°C; And / or, the plasma chemical vapor deposition time is 10 to 30 minutes.

7. The method according to claim 4, characterized in that The concentration of the organosiloxane monomer source in the reaction chamber increases continuously during the deposition process; The concentration of the organic siloxane monomer source in the reaction chamber is increased by reducing the flow rate of the straight-through inert gas during the deposition process, and the flow rate reduction rate of the straight-through inert gas is 5 to 50 sccm / min; And / or, the discharge power gradually decreases during the deposition process, with a decrease rate of 5 to 30 W / min.

8. The method according to claim 7, characterized in that The concentration of the organic siloxane monomer source in the reaction chamber is increased by reducing the flow rate of the straight-through inert gas during the deposition process. The initial flow rate of the straight-through inert gas is 1500-800 sccm, and the flow rate of the straight-through inert gas is gradually reduced to 600-200 sccm during the deposition process. The flow rate reduction rate of the straight-through inert gas is 10-30 sccm / min. And / or, the initial discharge power of the plasma chemical vapor deposition is 400-1000W, and the discharge power gradually decreases to 100-400W during the deposition process; the reduction rate of the discharge power is 10-20W / min.

9. The method according to claim 1, characterized in that: The substrate is placed in the reaction chamber after being pre-treated; the pre-treatment includes: cleaning and plasma surface treatment; The gases for plasma surface treatment are argon and oxygen; The argon-oxygen ratio of the plasma surface treatment is 1 to 0.2:1; And / or, the discharge power of the plasma surface treatment is 200 to 500 W; And / or, the plasma surface treatment time is 2 to 10 minutes.

10. A hydrophobic film layer, characterized in that: The method is prepared by any one of claims 1 to 9.

11. The hydrophobic film layer according to claim 10, characterized in that: The hydrophobic film layer includes element Si, element C and element O; the carbon-oxygen ratio of the bottom of the hydrophobic film layer is (0.2-2.5):(0.7-2.3); the carbon-oxygen ratio of the surface layer of the hydrophobic film layer is (1.6-2.7):(0.5-1).

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