阅读说明：本技术 一种类氧化硅柔性薄膜的生长方法 (Growth method of silicon oxide-like flexible film ) 是由 张宇 韩琳 于 2020-07-06 设计创作，主要内容包括：本发明公开了一种类氧化硅柔性薄膜的生长方法,包括如下过程：将衬底放入PECVD的反应腔体内,面朝反应腔体内的射频电极,衬底与射频电极的距离保持在5-25mm,抽真空；当反应腔体内真空度达到设定值时,通入氧气、六甲基硅氧烷和氮气,然后打开射频电源,开始在衬底上生长薄膜；当薄膜生长到期望的厚度时,关闭射频电源,然后停止通入反应气体,关闭真空泵；再通入氮气,当反应腔体内的压力达到大气压后,开启顶盖,取出生长好的薄膜,关闭顶盖；抽真空,然后通入四氟化碳气体,打开射频电源,对反应腔体进行清洗。本发明所公开的方法生长的薄膜具有很好的光学和电学特性,以及很好的致密性和机械柔性,可以作为很好的柔性薄膜封装材料。(The invention discloses a growth method of a silicon oxide-like flexible film, which comprises the following steps: putting the substrate into a reaction cavity of the PECVD, facing a radio-frequency electrode in the reaction cavity, keeping the distance between the substrate and the radio-frequency electrode at 5-25mm, and vacuumizing; when the vacuum degree in the reaction cavity reaches a set value, introducing oxygen, hexamethyl siloxane and nitrogen, then turning on a radio frequency power supply, and starting to grow a film on the substrate; when the film grows to the expected thickness, the radio frequency power supply is closed, then the reaction gas is stopped to be introduced, and the vacuum pump is closed; then introducing nitrogen, opening the top cover when the pressure in the reaction cavity reaches the atmospheric pressure, taking out the grown film, and closing the top cover; vacuumizing, introducing carbon tetrafluoride gas, turning on a radio frequency power supply, and cleaning the reaction cavity. The film grown by the method disclosed by the invention has good optical and electrical properties, good compactness and mechanical flexibility, and can be used as a good flexible film packaging material.)

1. A method for growing a silicon oxide-like flexible film is characterized by comprising the following steps:

(1) sample loading: putting the substrate into a reaction cavity of the PECVD, facing a radio-frequency electrode in the reaction cavity, keeping the distance between the substrate and the radio-frequency electrode at 5-25mm, and vacuumizing;

(2) growing a film: when the vacuum degree in the reaction cavity reaches a set value, introducing oxygen, hexamethyl siloxane and nitrogen, then turning on a radio frequency power supply, exciting the reaction gas in the reaction cavity to a plasma state by the radio frequency power supply through a radio frequency electrode, and carrying out chemical deposition reaction on the plasma of the hexamethyl siloxane, the nitrogen and the oxygen to start to grow a film on the substrate;

(3) when the film grows to the expected thickness, the radio frequency power supply is closed, then the introduction of oxygen, hexamethyl siloxane and nitrogen is stopped, and the vacuum pump is closed; then introducing nitrogen, opening the top cover when the pressure in the reaction cavity reaches the atmospheric pressure, taking out the grown film, and closing the top cover;

(4) cleaning a reaction cavity: vacuumizing the reaction cavity, introducing carbon tetrafluoride gas, turning on a radio frequency power supply, and etching silicon oxide-like substance deposited in the reaction cavity during film growth by using the carbon tetrafluoride plasma to clean the reaction cavity; after cleaning, the radio frequency power supply is turned off, and then the carbon tetrafluoride gas is turned off.

2. The method for growing a silicon oxide-like flexible film according to claim 1, wherein the substrate is selected from polyimide, polyisoprene or plastic film.

3. The method for growing a silicon oxide-like flexible film according to claim 1, wherein the substrate is cleaned by first cleaning with Micro-90 cleaning solution, acetone, isopropanol and deionized water.

4. The method for growing a flexible thin film of silicon oxide as claimed in claim 1, wherein in step (2), when the vacuum degree in the reaction chamber is lower than 1x10^-6While the Torr is being used, oxygen, hexamethyl siloxane and nitrogen are introduced.

5. The method for growing a flexible thin film of silicon oxide according to claim 1, wherein in the step (2), hexamethyl siloxane is introduced in an amount of 1-10% by volume of the total gas, and oxygen is introduced in an amount of 80-90% by volume of the total gas.

6. The method for growing a silicon oxide-like flexible film according to claim 1, wherein in the step (4), the reaction chamber is evacuated for 5-15 minutes and then carbon tetrafluoride gas is introduced.

Technical Field

The invention relates to a growth method of a flexible film, in particular to a growth method of a silicon oxide-like flexible film.

Background

Currently, OLEDs display screens or other electronic products are basically packaged by glass plate/epoxy resin or polymer/Al₂O₃/polymer/Al₂O₃… packaging mode of multilayer structure. Glass plate/epoxy encapsulation cannot be applied to flexible electronics. In the multi-layer packaging structure, the package structure,polymers do not have oxygen blocking capability, Al₂O₃Although dense but brittle, it is prone to form micro-pore cracks, and the path of oxygen to OLEDs is lengthened only in a certain range through detour, so that it does not completely block.

In addition, flexible electronics has a very good application prospect, however, electronic devices are required to be flexible, and flexible metal conductive materials, flexible semiconductor materials and flexible insulating dielectric materials are required. At present, the flexible metal materials comprise gold, silver, aluminum and the like, the flexible semiconductor materials comprise part of organic semiconductors, but the flexible insulating dielectric materials are not well selected, and particularly the flexible insulating dielectric materials can be prepared at room temperature.

Disclosure of Invention

In order to solve the technical problems, the invention provides a growing method of a silicon oxide-like flexible film, so that the grown film has good optical and electrical properties, good compactness and mechanical flexibility and can be used as a good flexible film packaging material.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method for growing a silicon oxide-like flexible film comprises the following steps:

(1) sample loading: putting the substrate into a reaction cavity of the PECVD, facing a radio-frequency electrode in the reaction cavity, keeping the distance between the substrate and the radio-frequency electrode at 5-25mm, and vacuumizing;

(2) growing a film: when the vacuum degree in the reaction cavity reaches a set value, introducing oxygen, hexamethyl siloxane and nitrogen, then turning on a radio frequency power supply, exciting the reaction gas in the reaction cavity to a plasma state by the radio frequency power supply through a radio frequency electrode, and carrying out chemical deposition reaction on the plasma of the hexamethyl siloxane, the nitrogen and the oxygen to start to grow a film on the substrate;

(3) when the film grows to the expected thickness, the radio frequency power supply is closed, then the introduction of oxygen, hexamethyl siloxane and nitrogen is stopped, and the vacuum pump is closed; then introducing nitrogen, opening the top cover when the pressure in the reaction cavity reaches the atmospheric pressure, taking out the grown film, and closing the top cover;

(4) cleaning a reaction cavity: vacuumizing the reaction cavity, introducing carbon tetrafluoride gas, turning on a radio frequency power supply, and etching silicon oxide-like substance deposited in the reaction cavity during film growth by using the carbon tetrafluoride plasma to clean the reaction cavity; after cleaning, the radio frequency power supply is turned off, and then the carbon tetrafluoride gas is turned off.

In the scheme, the substrate is made of polyimide, polyisoprene or a plastic film.

In the scheme, the substrate is cleaned by Micro-90 cleaning solution, acetone, isopropanol and deionized water.

In the scheme, in the step (2), when the vacuum degree in the reaction cavity is lower than 1x10^-6While the Torr is being used, oxygen, hexamethyl siloxane and nitrogen are introduced. In the scheme, in the step (2), the introduced hexamethyl siloxane accounts for 1-10% of the total gas volume, and the introduced oxygen accounts for 80-90% of the total gas volume.

In the scheme, in the step (4), the reaction cavity is vacuumized for 5-15 minutes, and then carbon tetrafluoride gas is introduced.

Through the technical scheme, the growing method of the silicon oxide-like flexible film provided by the invention has the following beneficial effects:

1. the film material prepared by the method has similar electrical and optical characteristics of thermal silicon oxide, most of the silicon and oxygen are remained after hexamethyl siloxane is oxidized by oxygen in the growth process, and few carbon and hydrogen exist, so that the film has good mechanical flexibility and compactness due to the small amount of carbon and hydrogen.

2. The method has low manufacturing cost, the used raw materials are oxygen, hexamethyl siloxane and nitrogen, the tail gas does not need to be specially treated, and the method has no pollution to the environment.

3. By adopting the method, the film growth temperature is low, and the film can grow on any substrate.

4. The step coverage of the film material is good, the growth speed is high, and can reach 2 um/hour.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is a schematic structural diagram of a reaction chamber according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a reaction chamber for growing a large-area thin film according to an embodiment of the present invention;

FIG. 3 is a graph of electrical properties of a silicon oxide-like flexible film prepared according to an embodiment of the present invention;

FIG. 4 is a graph of the optical properties of a silicon oxide-like flexible film prepared according to an embodiment of the present invention;

FIG. 5 is a diagram illustrating the effect of flexibility of a transistor device fabricated from a silicon oxide-like flexible thin film fabricated according to an embodiment of the present invention;

FIG. 6 is a step coverage image of a silicon oxide-like flexible film prepared according to an embodiment of the present invention;

FIG. 7 is a step coverage scattergram of a silicon oxide-like flexible film prepared according to an embodiment of the present invention;

FIG. 8 is a diagram illustrating the packaging effect of a silicon oxide-like flexible film prepared according to an embodiment of the present invention on OLEDs.

In the figure, 1, a reaction chamber; 2. a radio frequency electrode; 3. a gas mixer; 4. a top cover; 5. a substrate; 6. a gas inlet; 7. a first gas outlet; 8. a gas outlet II; 9. a temperature sensor; 10. a roller; 11. a gas baffle; 12. and (4) a bracket.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The invention provides a growth method of a silicon oxide-like flexible film, which comprises the following specific embodiments:

(1) cleaning a substrate: firstly, a substrate to be grown, such as a substrate material of polyimide, polyisoprene, plastic film and the like, is cleaned by Micro-90 cleaning solution, acetone, isopropanol and deionized water, and a chip or a substrate grown with devices or cleaned can be not cleaned.

(2) Sample loading: putting a substrate into a reaction cavity of the PECVD, facing a radio-frequency electrode in the reaction cavity, keeping the distance between the substrate and the radio-frequency electrode at 5-25mm, closing a top cover, and vacuumizing;

(3) growing a film: when the vacuum degree in the reaction cavity is lower than 1x10^-6When the Torr is used, oxygen, hexamethyl siloxane and nitrogen are introduced, the introduced hexamethyl siloxane accounts for 5% of the total gas volume, and the introduced oxygen accounts for 85% of the total gas volume. Then turning on a radio frequency power supply, exciting the reaction gas in the reaction cavity to a plasma state by the radio frequency power supply through a radio frequency electrode, and starting to grow a thin film on the substrate after the plasma of hexamethyl siloxane, nitrogen and oxygen generates a chemical deposition reaction;

(4) when the film grows to the expected thickness, the radio frequency power supply is closed, then the introduction of oxygen, hexamethyl siloxane and nitrogen is stopped, and the vacuum pump is closed; then introducing nitrogen, opening the top cover when the pressure in the reaction cavity reaches the atmospheric pressure, taking out the grown film, and closing the top cover;

(5) cleaning a reaction cavity: vacuumizing the reaction cavity, introducing carbon tetrafluoride gas after 10 minutes, turning on a radio frequency power supply, and etching silicon oxide-like substance deposited in the reaction cavity during film growth by using the carbon tetrafluoride plasma to clean the reaction cavity; after cleaning, the radio frequency power supply is turned off, and then the carbon tetrafluoride gas is turned off.

The reaction cavity of the PECVD adopted by the invention is shown in figure 1, a radio frequency electrode 2 is suspended in the reaction cavity 1 horizontally, the radio frequency electrode 2 is connected with the anode of a radio frequency power supply, and the reaction cavity 1 is connected with the cathode of the radio frequency power supply; the gas mixing device 3 is arranged below the radio-frequency electrode 2, a substrate 5 for depositing a film is fixed on the inner side of a top cover 4 of the reaction cavity 1, the front surface of the substrate 5 faces the radio-frequency electrode 2, the gas mixing device 3 is connected with a gas circuit system through a gas inlet 6, and a gas outlet 7 connected with a vacuum system is arranged at the bottom of the reaction cavity 1. The side wall of the reaction cavity 1 is provided with a second gas outlet 8, the second gas outlet 8 is provided with a valve, the second gas outlet 8 is used for discharging gas in the reaction cavity 1, and when the pressure is too high, the gas can be discharged through the second gas outlet 8. A temperature sensor 9 is arranged on the top cover 4 of the reaction cavity 1 and used for monitoring the temperature in the reaction cavity 1.

The present invention can also be used with a reaction chamber of PECVD as shown in fig. 2, which can be used to grow large area thin films. The structure of the device is different from that of the device shown in figure 1 in that the substrate 5 is fixed on two rollers 10, one roller 10 is used for releasing the substrate 5, and the other roller 10 is used for rolling the substrate 5 with deposited film in the deposition process, so that large-area flexible film can be continuously grown. In addition, in order to prevent the deposition of the gas on the rollers 10, a cylindrical gas barrier 11 is provided between the two rollers 10, and gaps are opened at both sides of the gas barrier 11, and the substrate 5 passes through the gaps on the gas barrier 11.

In the structure, the gas mixing device 3, the radio-frequency electrode 2 and the gas baffle plate 11 are all arranged on the support 12, and the bottom of the support 12 is fixed at the bottom of the reaction cavity 1.

The silicon oxide-like flexible film prepared by the invention is subjected to performance test, the electrical characteristics of the silicon oxide-like flexible film are shown in fig. 3, the relative dielectric constant of the grown film is closely related to the deposition power of a radio frequency power supply during growth, and the relative dielectric constant of the grown film is increased along with the increase of the power; at 40W, the relative dielectric constant of the silicon oxide-like film is close to that of silicon dioxide prepared by a thermal oxidation method. When the power is increased, more carbon and hydrogen elements in the hexamethyl siloxane fully react with oxygen to generate gas and the gas is discharged through tail gas, the carbon and hydrogen elements in the film are reduced, and the content of silicon oxygen is closer to the content of silicon dioxide.

The optical characteristics of the film are shown in FIG. 4, the components of the silicon oxide-like film material grown at a deposition power of 40W are close to the silicon dioxide prepared by the thermal oxidation method, the optical permeability of the silicon oxide-like film material is similar to the optical permeability of the silicon dioxide prepared by the thermal oxidation method, and the permeability of the silicon oxide-like film material is very good in the range of 350-2400 nm.

Mechanical flexibility tests of the film show that the 2-micron-thick silicon oxide-like film does not have any microcrack after being curled 60000 times on a 25-micron-thick flexible substrate, the prepared silicon oxide-like film is used as a gate dielectric layer of a flexible transistor, the transistor is bent on a curved surface with the diameter of 1mm, and the performance of the device is not affected at all, and as shown in FIG. 5, the film prepared by the invention has good mechanical flexibility.

Step coverage of the film as shown in fig. 6 and 7, coverage of the film at the step is important in a device or chip package. The film with good coverage can form an effective protective layer at the step, and the silicon oxide-like flexible film material can grow on the side wall and the bottom of the step due to uniform reaction of plasma at the step in the growth process to form better step coverage.

The packaging effect of the film on OLEDs is shown in figure 8, accelerated test is carried out under the conditions of 65 ℃ and 85% humidity, and the 2um thick silicon oxide-like film deposited on the OLEDs by the method can effectively protect the OLEDs. The active area of OLEDs is gradually reduced in an accelerated reaction (65 ℃, 85% humidity), but at a much slower rate than the glass-encapsulated products on the market today, i.e. the blocking of water vapour and oxygen is much better than other types of encapsulation.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.