Preparation method of high-transmittance indium tin oxide film

Abstract

The invention provides a preparation method of a high-transmittance indium tin oxide film, and the preparation method is as follows: the film deposition mode of the indium tin oxide film adopts magnetron sputtering coating, after a substrate enters a process cavity, ArH2 and O2 gas are introduced into the cavity, the flow of the ArH2 gas is 50-1000Sccm, and the flow of the O2 gas is 16-24Sccm; when the atmosphere of the cavity reaches a preset value, high-energy electrons in the plasma are used for impacting process gas molecules, chemical bonds of the process gas molecules are broken, and Ar ions, oxygen ions and electrons are generated; the Ar ions bombard the surface of the ITO target material, so that the indium tin oxide ions are sputtered on the substrate; meanwhile, oxygen ions fill up surface defects of the film, so that the surface of the film is flatter and smoother, and an indium tin oxide film is formed. According to the method, the oxygen content is optimized in the magnetron sputtering coating method, the ITO film property is improved, the transmittance effect of the ITO film is optimal, and therefore the transmittance of a thin film transistor (TFT) is improved.

Description

[Technical field]

[0001] The invention relates to the technical field of thin film transistor preparation, and in particular to a method for preparing an indium tin oxide film with high transmittance. [Background technology]

[0002] Thin film transistors (TFTs) are the most widely used display driver cores in the current liquid crystal display industry, mainly including amorphous silicon thin film transistors (a-Si TFTs) and polycrystalline silicon thin film transistors (p-Si TFTs). In the manufacturing process of TFTs, the ITO film (indium tin oxide film) is used as a transparent conductive layer, and its transmittance and conductivity have a direct impact on the performance of TFTs. ITO film has the characteristics of high transmittance, excellent conductivity, and high mechanical strength, and plays an important role in TFTs. Specifically, as an n-type semiconductor material, the special effect of ITO film with high transmittance is conducive to improving the transparency of thin film transistors (TFTs), so it is very suitable for the channel layer of TFTs. In addition, the preparation process and performance of ITO film (such as transmittance, resistivity, etc.) also have an important influence on the operating voltage and stability of amorphous silicon TFTs. Therefore, the transmittance of amorphous silicon TFTs is closely related to the performance parameters of ITO film such as transmittance and conductivity. By optimizing the performance of ITO film, the performance of amorphous silicon TFTs can be significantly improved. [Summary of the invention]

[0003] The technical problem to be solved by the present invention is to provide a method for preparing an indium tin oxide film with high transmittance, by optimizing the oxygen content in the magnetron sputtering coating method, improving the ITO film properties, and making its transmittance effect optimal, thereby improving the transmittance of TFT.

[0004] The present invention is achieved in that:

[0005] A method for preparing an indium tin oxide film with high transmittance, the method is as follows: the indium tin oxide film is deposited by magnetron sputtering, after a substrate enters a process chamber, ArH2 and O2 gases are introduced into the chamber, the flow rate of the ArH2 gas is 310 Sccm, and the flow rate of the O2 gas is 16-24 Sccm; when the chamber atmosphere reaches a preset value, high-energy electrons in the plasma are used to collide with process gas molecules to break their chemical bonds, generating Ar ions, oxygen ions and electrons; Ar ions bombard the surface of an ITO target material, so that the indium tin oxide ions are sputtered on the substrate; at the same time, the oxygen ions fill the surface defects of the film, making the surface more flat and smooth, forming an indium tin oxide film.

[0006] Furthermore, the preparation method is specifically as follows:

[0007] Step 1: Send the substrate to be processed into the atmospheric environment and into the buffer zone of the vacuum environment through a vacuum conveying mechanism;

[0008] Step 2: Send the substrate from the buffer zone into PM1 for substrate cleaning and preheating to ensure that the glass substrate is heated evenly;

[0009] Step 3: After the substrate is preheated, it is sent into the PM2 coating chamber for magnetron sputtering coating: After the substrate is sent into the PM2 coating chamber, ArH2 and O2 gases are introduced into the chamber, and the flow rate of ArH2 gas is 50-1000 Sccm, and the flow rate of O2 gas is 16-24 Sccm; the chamber pressure is controlled at 0.1-1 Pa. After the voltage stabilization is completed, the plasma dissociates the gas and bombards the target surface with an output power of 1000-20000W, so that the indium tin oxide ions are sputtered on the substrate, and at the same time, the oxygen ions fill the surface defects of the film;

[0010] Step 4: After the substrate is processed, it is sent from the PM2 coating chamber into the vacuum environment and then into the atmospheric environment buffer zone;

[0011] Step 5: Send the completed process cassette back to the carrying cassette through the robotic arm.

[0012] Furthermore, in step three, the flow rate of ArH2 gas is 310 Sccm, the flow rate of O2 gas is 20 Sccm, the cavity pressure is 0.25 Pa, and the output power is 12000W.

[0013] The present invention has the following advantages:

[0014] The present invention significantly improves the surface morphology and transmittance of the indium tin oxide film by adjusting the optimal oxygen concentration between 16sccm and 24sccm in magnetron sputtering coating, and when the oxygen concentration flow is 20sccm, the surface of the indium tin oxide film is the smoothest and flattest, and the transmittance reaches the highest. That is, the present invention optimizes and improves the ITO film quality characteristics by adjusting the optimal oxygen concentration in the magnetron sputtering coating method, and makes the transmittance effect reach the best without affecting other properties such as the electrical properties of amorphous silicon TFT, thereby improving the transmittance of TFT.

Brief Description of the Drawings

[0015] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0016] Figure 1 Schematic diagram of the target surface bombarded by dissociated plasma in an embodiment of the present invention.

[0017] Figure 2 The electron scanning microscope images show the difference in surface morphology of the ITO film under different oxygen concentrations in the embodiment of the present invention.

[0018] Figure 3 This is a diagram showing the difference in light transmittance of the ITO film under different oxygen concentrations in an embodiment of the present invention.

[0019] Figure 4 This is a comparison chart of the transmittance of a TFT single board using a new ITO film and an old ITO film in an embodiment of the present invention.

[0020] Figure 5 This is a comparison chart of the yield of TFT products using the new ITO film and the old ITO film in the embodiment of the present invention. [Specific implementation method]

[0021] The invention relates to a preparation method of an indium tin oxide film with high transmittance. The preparation method is as follows: the indium tin oxide film is deposited by magnetron sputtering, and after a substrate enters a process chamber, ArH2 and O2 gases are introduced into the chamber, wherein the flow rate of the ArH2 gas is 310 Sccm, and the flow rate of the O2 gas is 16-24 Sccm; when the chamber atmosphere reaches a preset value, high-energy electrons in plasma are used to collide with process gas molecules to break their chemical bonds, thereby generating Ar ions, oxygen ions and electrons; the Ar ions bombard the surface of an ITO target material, thereby sputtering indium tin oxide ions onto the substrate; and at the same time, the oxygen ions fill the surface defects of the film, thereby making the surface more flat and smooth, thereby forming an indium tin oxide film.

[0022] The preparation method is specifically as follows:

[0023] Step 1: Send the substrate to be processed into the atmospheric environment and into the buffer zone of the vacuum environment through a vacuum conveying mechanism;

[0024] Step 2: Send the substrate from the buffer zone into PM1 for substrate cleaning and preheating to ensure that the glass substrate is heated evenly;

[0025] Step 3: After the substrate is preheated, it is sent into the PM2 coating chamber for magnetron sputtering coating: After the substrate is sent into the PM2 coating chamber, ArH2 and O2 gases are introduced into the chamber, and the flow rate of ArH2 gas is 50-1000 Sccm, and the flow rate of O2 gas is 16-24 Sccm; the chamber pressure is controlled at 0.1-1 Pa. After the voltage stabilization is completed, the plasma dissociates the gas and bombards the target surface with an output power of 1000-20000W, so that the indium tin oxide ions are sputtered on the substrate, and at the same time, the oxygen ions fill the surface defects of the film;

[0026] Step 4: After the substrate is processed, it is sent from the PM2 coating chamber into the vacuum environment and then into the atmospheric environment buffer zone;

[0027] Step 5: Send the completed process cassette back to the carrying cassette through the robotic arm.

[0028] Preferably, in step three, the flow rate of ArH2 gas is 310 Sccm, the flow rate of O2 gas is 20 Sccm, the chamber pressure is 0.25 Pa, and the output power is 12000 W.

[0029] The following will be combined with the attached Figure 1-5 The technical scheme of the present invention is clearly and completely described in detail with specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0030] 1. The following embodiments mainly regulate the O2 gas flow rate in step 3 so that ITO films of different film qualities are formed on the glass substrate under different oxygen concentration conditions. The specific parameters are shown in Table 1:

[0031] Table 1 ITO film quality debugging parameters

[0032]

[0033] The above embodiments of the present invention significantly improve the surface morphology of the ITO film (indium tin oxide film) by adjusting different oxygen concentrations. Figure 2 As shown in the figure, when the oxygen concentration flow rate is 4 sccm, the surface roughness of ITO is 0.361 (Ra), and when the oxygen concentration is 20 sccm, the surface roughness of ITO is 0.146 (Ra), that is, the surface of ITO film is smoother and flatter. The nonlinear performance of oxygen concentration and transmittance is as follows Figure 3 As shown, the transmittance peak is between 16 sccm and 24 sccm, and when the oxygen concentration flow rate is 20 sccm, the transmittance is as high as 91.5.

[0034] 2. The new ITO film prepared with an oxygen concentration of 20 sccm and the old ITO film prepared with an oxygen concentration of 4 sccm (other parameters are the same as above) are used in amorphous silicon thin film transistors (a-Si TFT) under different product designs. The penetration rate and product yield of each TFT single board are as follows Figure 4 and 5 shown.

[0035] from Figure 4 Experimental data show that the new ITO film with an oxygen concentration of 20 sccm (magnetron sputtering coating method) has a significant improvement in the penetration of amorphous silicon thin-film transistors (a-Si TFT) under different product designs. Compared with the old ITO film with an oxygen concentration of 4 sccm, the overall transmittance is increased by 7.1% to 8.9% compared with the case of using the old ITO film.

[0036] from Figure 5 It can be seen that using TFT panel quality inspection equipment, it is confirmed that the yield of the new ITO film product with an oxygen concentration of 20sccm is no lower than that of the old film.

[0037] In summary, the present invention significantly improves the surface morphology and transmittance of the indium tin oxide film by adjusting the optimal oxygen concentration between 16sccm-24sccm in magnetron sputtering coating, and when the oxygen concentration flow is 20sccm, the surface of the indium tin oxide film is the smoothest and flattest, and the transmittance reaches the highest. That is, the present invention optimizes and improves the ITO film quality characteristics by adjusting the optimal oxygen concentration in the magnetron sputtering coating method, and makes the transmittance effect reach the best without affecting other properties such as the electrical properties of amorphous silicon TFT, thereby improving the transmittance of TFT.

[0038] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a high-transmittance indium tin oxide film, characterized in that: The preparation method is as follows: the deposition method of the indium tin oxide film adopts magnetron sputtering coating, after the substrate enters the process chamber, ArH2 and O2 gases are introduced into the chamber, the flow rate of the ArH2 gas is 50-1000 Sccm, and the flow rate of the O2 gas is 16-24 Sccm; when the chamber atmosphere reaches a preset value, high-energy electrons in the plasma are used to collide with process gas molecules, break their chemical bonds, and generate Ar ions, oxygen ions and electrons; Ar ions bombard the surface of the ITO target material, so that the indium tin oxide ions are sputtered on the substrate; at the same time, the oxygen ions fill the surface defects of the film, making its surface more flat and smooth, and forming an indium tin oxide film.

2. The method for preparing a high-transmittance indium tin oxide film according to claim 1, characterized in that: The preparation method is specifically as follows: Step 1: Send the substrate to be processed into the atmospheric environment and into the buffer zone of the vacuum environment through a vacuum conveying mechanism; Step 2: Send the substrate from the buffer zone into PM1 for substrate cleaning and preheating to ensure that the glass substrate is heated evenly; Step 3: After the substrate is preheated, it is sent into the PM2 coating chamber for magnetron sputtering coating: After the substrate is sent into the PM2 coating chamber, ArH2 and O2 gases are introduced into the chamber, and the flow rate of ArH2 gas is 50-1000 Sccm, and the flow rate of O2 gas is 16-24 Sccm; the chamber pressure is controlled at 0.1-1 Pa. After the voltage stabilization is completed, the plasma dissociates the gas and bombards the target surface with an output power of 1000-20000W, so that the indium tin oxide ions are sputtered on the substrate, and at the same time, the oxygen ions fill the surface defects of the film; Step 4: After the substrate is processed, it is sent from the PM2 coating chamber into the vacuum environment and then into the atmospheric environment buffer zone; Step 5: Send the completed process cassette back to the carrying cassette through the robotic arm.

3. A method for preparing a high-transmittance indium tin oxide film according to claim 1 or 2, characterized in that: In the step three, the flow rate of ArH2 gas is 310 Sccm, the flow rate of O2 gas is 20 Sccm, the cavity pressure is 0.25 Pa, and the output power is 12000 W.

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