A method for depositing silicon nitride film on indium gallium zinc oxide

Abstract

A method for depositing silicon nitride (SiN) films on indium gallium zinc oxide (IGNOW) includes: placing a glass substrate to which a SiN insulating layer is to be deposited into a CVD vacuum chamber via a vacuum transfer mechanism; bringing the glass substrate to which the SiN insulating layer is to be deposited into contact with a heated support base to ensure uniform heating of the glass substrate; simultaneously introducing NH3 and SiH4 into the vacuum chamber and controlling the vacuum chamber pressure at 1350 mtorr using a pressure regulating valve; depositing a thin film onto the glass substrate using plasma dissociation process gases at an output power of 5500 W; and after the deposition is complete, shutting off the plasma system and venting the NH3, SiH4, and H2 gases from the vacuum chamber. This invention provides a low-stress SiN insulating film that can effectively prevent product display abnormalities caused by film breakage.

Description

Technical Field

[0001] This invention belongs to the technical field of semiconductor thin film fabrication methods, specifically referring to a silicon nitride deposition method used on indium gallium zinc oxide. Background Technology

[0002] Indium gallium zinc oxide (IGZO) thin films have the characteristics of high mobility and high transmittance. As an active layer, they are widely used in thin film transistors (TFTs). In order to better utilize the characteristics of IGZO materials and make the product performance more stable and reliable, the composition structure between devices needs to be optimized.

[0003] Because of the sensitive nature of IGZO materials, oxygen vacancies are easily generated during reducing atmosphere annealing, leading to electrical instability. Therefore, silicon oxide (SiOx) films are generally used as the insulating layer. However, the silicon oxide films currently in production are relatively loose and have a slow deposition rate, making them susceptible to damage from foreign matter in the production environment and the deposition chamber environment. This damage can cause short circuits between the upper and lower indium tin oxide metal layers in the capacitor environment (e.g., ...). Figure 1 As shown), this causes poor product display, and oxygen ions during the silicon oxide deposition process can erode the organic layer (such as...). Figure 1 As shown in the figure, this results in poor product appearance. To improve product performance and appearance, silicon nitride insulating film can be used to replace silicon oxide.

[0004] However, the high-power deposition environment and hydrogen ions in the existing silicon nitride insulating film production can cause oxygen to detach from the IGZO lattice, forming oxygen vacancies. High-power deposition can also generate greater stress, causing the insulation layer to deteriorate and form leakage paths, which in turn leads to poor panel display. Therefore, it is necessary to reduce the stress of the silicon nitride insulating film so that it can be adapted to IGZO products to improve quality.

[0005] The main components of silicon nitride films are silane (SiH4) and ammonia (NH3). Its high deposition power creates a high electric field, which can easily cause electrical deviations in IGZO devices. Furthermore, the high hydrogen content in the film causes oxygen to detach from the IGZO lattice, creating oxygen vacancies, which can lead to leakage paths and poor panel display. Low-stress silicon nitride, by adjusting the gas flow rates of silane and ammonia, as well as the deposition power and pressure, results in a smaller collapse electric field and a lower hydrogen content in the film, making it more suitable for IGZO devices. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for depositing silicon nitride on indium gallium zinc oxide, which provides a low-stress silicon nitride insulating film.

[0007] This invention is implemented as follows:

[0008] A method for depositing silicon nitride films on indium gallium zinc oxide includes the following steps:

[0009] Step S1: The glass substrate to which the silicon nitride insulating layer is to be deposited is placed into the CVD (Chemical Vapor Deposition) vacuum chamber through a vacuum transfer mechanism;

[0010] Step S2: The glass substrate to which the silicon nitride insulating layer is to be deposited is brought into contact with the heated support base to ensure that the glass substrate is heated evenly.

[0011] Step S3: Simultaneously introduce NH3 7290 sccm and SiH4 3240 sccm into the vacuum chamber, and control the pressure of the vacuum chamber at 1350 mtorr through the pressure regulating valve;

[0012] Step S4: A silicon nitride thin film is deposited on a glass substrate by plasma dissociation of the process gas from step S3 at an output power of 5500W.

[0013] Step S5: After the film deposition is completed, shut down the plasma system and remove the NH3, SiH4, and H2 gases from the vacuum chamber;

[0014] Step S6: Transfer the substrate after film deposition out of the vacuum chamber to complete the silicon nitride deposition process.

[0015] Furthermore, the distance between the upper and lower electrodes inside the vacuum chamber is 1000 mils.

[0016] The advantages of this invention are as follows: The method of this invention provides a low-stress silicon nitride insulating film, which makes the electrical properties of IGZO devices unaffected by the film deposition environment, electrical bias voltage, hydrogen content, etc., and will not affect the electrical properties due to the connection with the IGZO semiconductor. In addition, the film has a high deposition rate, good uniformity of the large board, is not easily affected by foreign objects in the production environment, and is not easily affected by film breakage, which may cause short circuit between the upper and lower indium tin oxide metal layers in the capacitor environment, resulting in abnormal product display. Attached Figure Description

[0017] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a schematic diagram of the cross-sectional structure of an IGZO array substrate film layer using a silicon oxide insulating layer in the prior art.

[0019] Figure 2 This is a schematic diagram of the method flow of the present invention.

[0020] Figure 3 This is a comparison table of the debugging parameters for two types of films: existing SiNx and the present invention (low-stress SiNx).

[0021] Figure 4This is a comparison image showing two types of films, existing SiNx and the present invention (low-stress SiNx), displayed using an electron scanning microscope.

[0022] Figure 5 The image shows a comparison of two types of films: existing SiNx and the present invention (low-stress SiNx), displayed using a macro-light inspection machine.

[0023] Figure 6 This is a comparison chart of the electrical properties of two types of films: existing SiNx and the present invention (low-stress SiNx).

[0024] Figure 7 The panel display testing machine is used to confirm the absence of relevant functional and grade defects in the film of this invention (low stress SiNx).

[0025] Figure 8 This is a comparison chart showing that the defect caused by foreign matter in the film deposition of the present invention (low-stress SiNx) is 29.6% lower than that of the silicon oxide film in the prior art.

[0026] Figure Labels

[0027] 1. Glass substrate; 2. TFT device; 3. Insulating layer; 4. Organic layer; 5. Pixel capacitor. Detailed Implementation

[0028] like Figure 2 As shown, a method for depositing silicon nitride films on indium gallium zinc oxide includes the following steps:

[0029] Step S1: The glass substrate to which the silicon nitride insulating layer is to be deposited is placed into the CVD (Chemical Vapor Deposition) vacuum chamber through a vacuum transfer mechanism;

[0030] Step S2: The glass substrate to which the silicon nitride insulating layer is to be deposited is brought into contact with the heated support base to ensure that the glass substrate is heated evenly.

[0031] Step S3: Simultaneously introduce NH3 at 7290 sccm and SiH4 at 3240 sccm into the vacuum chamber, and control the pressure in the vacuum chamber at 1350 mtorr using a pressure regulating valve; the distance between the upper and lower electrodes in the vacuum chamber is 1000 mils.

[0032] Step S4: A silicon nitride thin film is deposited on a glass substrate by plasma dissociation of the process gas from step S3 at an output power of 5500W.

[0033] Step S5: After the film deposition is completed, shut down the plasma system and remove the NH3, SiH4, and H2 gases from the vacuum chamber;

[0034] Step S6: Transfer the substrate after film deposition out of the vacuum chamber to complete the silicon nitride deposition process.

[0035] The main components of silicon nitride films are silane (SiH4) and ammonia (NH3), such as... Figure 3 As shown, the high deposition power of IGZO devices creates a high electric field that can easily cause electrical deviations in the IGZO device. Furthermore, the high hydrogen content in the deposition film causes oxygen to detach from the IGZO lattice, creating oxygen vacancies and resulting in leakage paths, leading to poor panel display. The low-stress silicon nitride of this invention adjusts the gas flow rates of silane and ammonia, as well as the deposition power and pressure, to create a smaller collapse electric field and a lower hydrogen content in the deposition film, making it more suitable for IGZO devices.

[0036] Figure 4 In the same production environment, the silicon oxide insulating layer and the low-stress silicon nitride insulating layer of the present invention were confirmed by electron scanning microscope to be affected by foreign objects during the deposition of the silicon oxide insulating film, which caused the film to break and short-circuit the upper and lower indium tin oxide metal layers. The normal deposition of the low-stress silicon nitride insulating film allowed the indium tin oxide to form a capacitor environment.

[0037] Figure 5 When the silicon oxide insulating film product was inspected by a Hongguang inspection machine, an appearance abnormality was detected. An electron scanning microscope confirmed that the organic layer was eroded by oxygen ions. The appearance and film structure of the low-stress silicon nitride insulating film product of this invention were normal.

[0038] Figure 6 This is a comparison of the electrical performance of currently produced silicon nitride films and low-stress silicon nitride films. Low-stress silicon nitride films have convergent critical voltage, better device switching ratio performance, and stable flat-band voltage, while silicon nitride films have no electrical properties.

[0039] Figure 7 The panel display testing machine is used to confirm the absence of relevant functional and grade defects in the film of this invention (low stress SiNx).

[0040] Figure 8 This is a comparison chart showing that the defect caused by foreign matter in the film deposition of the present invention (low-stress SiNx) is 29.6% lower than that of the silicon oxide film in the prior art.

[0041] The low-stress silicon nitride film prepared by the method of the present invention can prevent leakage current of IGZO semiconductors caused by high electric fields by reducing the stress of the insulating film. In addition, the film has a high deposition rate and good density, which can effectively prevent product display abnormalities caused by film breakage.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for depositing silicon nitride films on indium gallium zinc oxide, characterized in that: Includes the following steps: Step S1: The glass substrate to which the silicon nitride insulating layer is to be deposited is placed into the CVD vacuum chamber through a vacuum transfer mechanism; Step S2: The glass substrate to which the silicon nitride insulating layer is to be deposited is brought into contact with the heated support base to ensure that the glass substrate is heated evenly. Step S3: Simultaneously introduce NH3 7290 sccm and SiH4 3240 sccm into the vacuum chamber, and control the pressure of the vacuum chamber at 1350 mtorr through the pressure regulating valve; Step S4: A silicon nitride thin film is deposited on a glass substrate by plasma dissociation of the process gas from step S3 at an output power of 5500W. Step S5: After the film deposition is completed, shut down the plasma system and remove the NH3, SiH4, and H2 gases from the vacuum chamber; Step S6: Transfer the substrate after film deposition out of the vacuum chamber to complete the silicon nitride deposition process.

2. The method for depositing silicon nitride on indium gallium zinc oxide as described in claim 1, characterized in that: The distance between the upper and lower electrodes inside the vacuum chamber is 1000 mils.

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