Method of forming pixel-defining layer, pixel-defining layer, and display device comprising same

Abstract

The present invention relates to a method of forming a pixel-defining layer for a display device by using a PECVD process, the method comprising: (a) a step for disposing, in a reaction chamber, a substrate in which a plurality of electrodes, electrically connected to a thin-film transistor in the lower part through a via hole, are formed; and (b) a step for forming, between the plurality of electrodes, a pixel-defining layer made of an amorphous carbon material through a PECVD process.

Description

Method for forming a pixel defining film, pixel defining film, and display device including the same

[0001] The present invention relates to a method for forming a pixel definition layer for defining the position and shape of pixels in a display device.

[0002] In addition, the present invention relates to a pixel defining film having excellent light absorption characteristics.

[0003] In addition, the present invention relates to a display device comprising a pixel defining film having excellent light absorption characteristics.

[0004] A display device is a device that expresses various colors by combining primary color pixels of red (R), green (G), and blue (B), and thereby displays visual information such as images or videos. The brightness of each pixel can be adjusted independently, and virtually any color can be realized through the combination of pixels.

[0005] A Pixel Defining Layer (PDL) is an insulating or patterning layer that defines the location and shape of pixels on a display substrate. Pixel Defining Layers are primarily used in self-emissive displays, such as OLED (Organic Light Emitting Diode) displays, QLED (Quantum-dot Light Emitting Diode) displays, and Micro LED (micro Light Emitting Diode) displays. The Pixel Defining Layer allows for a clear distinction between light-emitting and non-light-emitting regions, thereby minimizing interference between RGB, which improves color accuracy, and enables the realization of high resolution. Pixel Defining Layers are also often referred to as banks.

[0006] The pixel definition film must have high insulation properties and excellent light absorption characteristics, namely a high absorption coefficient (K), to suppress external light reflection and improve contrast ratio.

[0007] The most common method for forming a pixel definition film was to spin-coat a photosensitive composition containing polyimide (PI) resin and a black pigment, and then pattern it through a photolithography process (e.g., Korean Patent Publication No. 10-2023-0104044, published July 7, 2023). Polyimide was widely used due to its excellent insulation and heat resistance properties, but there was a problem with the light-emitting material spreading in the inkjet process because it was difficult to control surface roughness. Additionally, black pigments such as carbon black, graphite, and graphene had problems such as non-uniform dispersion due to aggregation and reduced insulation reliability due to increased conductivity.

[0008] The problem that the present invention aims to solve is to provide a method for forming a pixel defining film for a display device that has high light absorption characteristics and can also have high insulation and pattern stability.

[0009] In addition, the problem that the present invention aims to solve is to provide a pixel defining film for a display device having excellent light absorption characteristics, insulation properties, and pattern stability.

[0010] In addition, the problem that the present invention aims to solve is to provide a display device including the pixel defining film described above.

[0011] The problems of the present invention are not limited to those mentioned above, and other problems and advantages of the present invention not mentioned can be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the problems and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0012] A method for forming a pixel defining film for a display device according to an embodiment of the present invention for solving the above problem comprises: (a) a step of placing a substrate having a plurality of electrodes formed thereon, which are electrically connected to a thin-film transistor at the bottom through via holes, in a reaction chamber; and (b) a step of forming a pixel defining film made of an amorphous carbon material between the plurality of electrodes by a PECVD process.

[0013] In some embodiments, step (b) may include the step of depositing an amorphous carbon film by discharging a carbon precursor under vacuum process pressure, a substrate temperature of about 200 to 500°C, and RF power of about 100 to 3000 W.

[0014] In some embodiments, in step (b), the process pressure may be about 6,000 mTorr or less. In some embodiments, in step (b), the process pressure may be about 3,000 mTorr or less.

[0015] In some embodiments, in step (b), the carbon precursor is CH4, C2H2, C2H4, C2H6, C3H6, C6H 12 It may include one or more of the following.

[0016] In some embodiments, in step (b), an inert gas and a nitrogen gas may be supplied into the reaction chamber along with the carbon precursor.

[0017] In some embodiments, the nitrogen gas may be supplied into the reaction chamber at a flow rate of about 300 to 10,000 sccm.

[0018] In some embodiments, in step (b), the process pressure may be about 6000 mTorr or less, and the nitrogen gas may be supplied into the reaction chamber at a flow rate of about 600 to 5000 sccm.

[0019] In some embodiments, the carbon precursor may be supplied into the reaction chamber at a flow rate of about 200 to 350 sccm.

[0020] In some embodiments, in step (b), the pixel defining film may be formed to cover the entire thin-film transistor and a portion of the plurality of electrodes.

[0021] A pixel defining film according to an embodiment of the present invention for solving the above problem is a pixel defining film for defining the position and shape of a plurality of pixels in a display device comprising a plurality of pixels, wherein the pixel defining film is made of an amorphous carbon material.

[0022] In some embodiments, the pixel defining film may have a K value of about 0.27 or higher.

[0023] In some embodiments, the pixel defining film may have a K value of about 0.30 or higher.

[0024] A display device according to an embodiment of the present invention for solving the above problem comprises: a substrate including a plurality of thin-film transistors; a plurality of electrodes disposed on the substrate including the plurality of thin-film transistors and electrically connected to the plurality of thin-film transistors through via holes; a pixel defining film disposed between the plurality of electrodes; and a light-emitting layer disposed on the plurality of electrodes, wherein the pixel defining film is made of amorphous carbon material.

[0025] In some embodiments, the pixel defining film may have a K value of about 0.27 or higher.

[0026] In some embodiments, the pixel defining film may have a K value of about 0.30 or higher.

[0027] In some embodiments, the pixel defining film may be formed to cover the entire thin-film transistor and a portion of the plurality of electrodes.

[0028] In some embodiments, the display device may be an OLED display device, a micro LED display device, or a QLED display device.

[0029] The pixel defining film for a display device according to the present invention is formed by amorphous carbon deposition using the PECVD method. Accordingly, the method for forming a pixel defining film according to the present invention has the advantage of suppressing moisture adsorption during the process compared to the method of forming a pixel defining film through a conventional lithography process.

[0030] In addition, since the pixel defining film according to the present invention is formed through amorphous carbon deposition by the PECVD method, the thickness of the film can be reduced, and accordingly, it can contribute to thinning the display device.

[0031] Furthermore, the method for forming a pixel defining film according to the present invention can maximize the light absorption rate while suppressing the light reflectance and light transmittance of the formed pixel defining film to the maximum extent by controlling the amorphous carbon deposition conditions, thereby absorbing incoming light from the outside and improving outdoor visibility. Moreover, the pixel defining film according to the present invention can serve as a substitute for a polarizer.

[0032] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below.

[0033] Figure 1 schematically shows a plurality of pixels and pixel defining films in a display device.

[0034] Figure 2 schematically shows a part of a display device in which a pixel definition film is formed.

[0035] FIG. 3 schematically illustrates a method for forming a pixel definition film for a display device according to an embodiment of the present invention.

[0036] FIG. 4 schematically illustrates an example of a PECVD device that can be used in a method for forming a pixel definition film for a display device according to the present invention.

[0037] Figure 5 is a graph showing the results of measuring the absorption coefficient (K) of the pixel definition film according to process pressure.

[0038] Figure 6 is a graph showing the results of measuring the absorption coefficient (K) of the pixel definition film according to the nitrogen gas flow rate.

[0039] Figure 7 is a graph showing the change in absorption rate according to the K value and wavelength of approximately 400–700 nm.

[0040] Figure 8 shows the change in the average absorption rate of visible light according to the K value.

[0041] The aforementioned objectives, features, and advantages are described in detail below, and accordingly, a person skilled in the art to which the present invention pertains will be able to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions may unnecessarily obscure the essence of the present invention. Hereinafter, preferred embodiments according to the present invention will be described in detail.

[0042] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0043] As used in this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “contains,” “has,” or “includes” should not be interpreted as necessarily including all of the various components described in the specification, and should be interpreted as meaning that some of the components may not be included or that additional components may be included.

[0044] Hereinafter, a method for forming a pixel defining film, a pixel defining film, and a display device including the same according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0045] Figure 1 schematically shows a plurality of pixels and pixel defining films.

[0046] The pixel defining film (110) is an insulating film or pattern film that defines the position and shape of pixels (120) on a display substrate.

[0047] A plurality of pixels (120), each defined by a pixel defining film (110), include a red pixel (120a, R), a green pixel (120b, G), and a blue pixel (120c, B). In some embodiments, some of the plurality of pixels (120) may additionally include a white pixel (W). The arrangement of the plurality of pixels (120) may be, for example, in a matrix form, but is not necessarily limited thereto.

[0048] The pixel defining film (110) is mainly used in self-emissive displays such as OLED (Organic Light Emitting Diode) displays, QLED (Quantum-dot Light Emitting Diode) displays, and micro LED (micro Light Emitting Diode) displays. The pixel defining film (110) allows the light-emitting region and the non-light-emitting region to be clearly distinguished, and accordingly, interference between RGB (RGBW if white pixels are included) is minimized, which can improve color accuracy and enable high resolution.

[0049] Figure 2 schematically shows a part of a display device in which a pixel definition film is formed.

[0050] Referring to FIG. 2, the display device includes a substrate (201), a plurality of electrodes (210), a pixel defining film (110), and a light-emitting layer (220).

[0051] The display device may be an OLED display device, a Micro LED display device, or a QLED display device.

[0052] The substrate (201) may be a glass substrate or a polymer substrate.

[0053] A plurality of thin-film transistors (202) are formed on a substrate (201). Although not shown in the drawing, each thin-film transistor (202) includes a gate electrode, a source electrode, and a drain electrode.

[0054] A plurality of electrodes (210) are disposed on a substrate (201) comprising a plurality of thin-film transistors (202). The plurality of electrodes (210) are electrically connected to the plurality of thin-film transistors (202) through via holes (203).

[0055] A pixel defining film (110) is placed between a plurality of electrodes (210). The size and shape of each RGB pixel can be determined by the pixel defining film (110), and mixing of colors between pixels can be prevented.

[0056] In the present invention, as described below, the pixel defining film (110) is formed of an amorphous carbon material. In other words, in the present invention, the pixel defining film (110) is formed of an amorphous carbon film.

[0057] A plurality of light-emitting layers (220) are disposed on a plurality of electrodes (210). The light-emitting layers can be formed as light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), quantum dot light-emitting diodes (QLEDs), or micro light-emitting diodes (micro LEDs).

[0058] Current is supplied to a plurality of electrodes (210) by driving a thin-film transistor (202), and accordingly, light of a predetermined color, such as red, green, or blue, is emitted from a light-emitting layer (220) electrically connected to each electrode.

[0059] FIG. 3 schematically illustrates a method for forming a pixel definition film for a display device according to an embodiment of the present invention.

[0060] Referring to FIG. 3, a method for forming a pixel defining film for a display device according to an embodiment of the present invention includes a substrate placement step (S310) and a pixel defining film formation step (S320) using a PECVD process.

[0061] First, in the substrate placement step (S310), a substrate is placed in the reaction chamber. A plurality of thin-film transistors and a plurality of electrodes are formed on the substrate. The plurality of electrodes are electrically connected to the lower thin-film transistor through via holes, as shown in the example in FIG. 2.

[0062] Next, the pixel defining film formation step (S320) includes the step of forming a pixel defining film made of amorphous carbon material between a plurality of electrodes by a PECVD process.

[0063] Specifically, the pixel defining film formation step (S320) may include a step of depositing an amorphous carbon film by discharging a carbon precursor under a vacuum process pressure, a substrate temperature of about 200 to 500°C, and an RF power of about 100 to 3000W. Between the substrate placement step (S310) and the pixel defining film formation step (S320) by the PECVD process, a reaction chamber vacuuming step, a carbon precursor supply step, a substrate heating step, etc., may be performed sequentially or simultaneously.

[0064] The pixel defining film according to the present invention is a thin film formed during the manufacturing process of a display device, and can be formed at approximately 200 to 500°C, more preferably at approximately 250 to 350°C. Meanwhile, if the substrate temperature exceeds approximately 500°C and is excessively high, the internal stress of the pixel defining film increases due to the difference in the coefficient of thermal expansion between the pixel defining film and the substrate, which may cause delamination or cracking of the pixel defining film.

[0065] The PECVD process for forming a pixel defining film according to the present invention is preferably performed under RF power conditions of about 100 to 3000 W, more preferably about 500 to 2500 W, and most preferably about 1000 to 2000 W. If the RF power is too high, exceeding about 3000 W, film stress may increase significantly. Conversely, if the RF power is too low, below about 100 W, it may be difficult to improve the K value of the deposited pixel defining film.

[0066] In addition, by performing the PECVD process under vacuum, it is possible to suppress the inclusion of unnecessary foreign substances in the pixel definition film formed.

[0067] In some embodiments, the process pressure may be about 6000 mTorr or less. In a preferred embodiment, the process pressure may be about 3000 mTorr or less. In this case, it is desirable because the absorption coefficient (K) of the pixel defining film formed can be significantly increased. In fact, a pixel defining film formed by a PECVD process at about 2000 mTorr exhibited an absorption coefficient (K) that was more than twice as high as that of a pixel defining film formed by a PECVD process at about 6000 mTorr. Due to this high absorption coefficient, the performance of the pixel defining film can be significantly improved.

[0068] Carbon precursors are CH4, C2H2, C2H4, C2H6, C3H6, and C6H 12 It may include one or more of the above, but is not necessarily limited thereto, and any carbon precursor used for amorphous carbon film deposition by the PECVD process may be used without limitation.

[0069] The carbon precursor can be supplied into the reaction chamber at a flow rate of about 200 to 350 sccm, and a flow rate of about 250 to 300 sccm is more preferable. If the flow rate of the carbon precursor is less than about 200 sccm, problems such as insufficient film thickness, non-uniformity of the film, and low light absorption characteristics may occur. However, if the flow rate of the carbon precursor exceeds about 350 sccm, the absorption coefficient may actually decrease significantly.

[0070] In some embodiments, an inert gas and a nitrogen gas may be supplied into the reaction chamber along with the carbon precursor. The inert gas may be argon or helium. The inert gas and the nitrogen gas may function as carrier gases.

[0071] In particular, nitrogen gas can play a role in improving the absorption coefficient (K) of the pixel definition film through doping. Nitrogen creates nitrogen-carbon bond structures within the amorphous carbon film, thereby electronically narrowing the band gap and increasing absorbable energy levels, which contributes to absorbing light over a wider wavelength range. Additionally, amorphous carbon films containing nitrogen can increase the absorption coefficient (K) due to reduced micropores and improved density.

[0072] It is preferable to supply nitrogen gas into the reaction chamber at a flow rate of approximately 300 sccm or more, and more preferable to supply it at a flow rate of approximately 600 to 10,000 sccm. In addition, membrane stress can be reduced as the nitrogen gas flow rate increases, and the decrease in the K value due to the decrease in RF power can be sufficiently compensated. The effect of increasing the absorption coefficient can become significant when the nitrogen gas flow rate is approximately 300 sccm or more. In particular, when the nitrogen gas flow rate is approximately 600 to 5,000 sccm, a high absorbance of approximately 0.3 or higher was observed. There is no specific upper limit for the nitrogen gas flow rate, but it may be limited to approximately 10,000 sccm or less for process purposes.

[0073] In some embodiments, the pixel defining film may be formed to cover the entire thin-film transistor and a portion of a plurality of electrodes, as in the example shown in FIG. 2. The size and shape of the electrodes exposed by the pixel defining film may be determined.

[0074] The pixel defining film for a display device formed by the method according to the present invention is made of amorphous carbon material. Amorphous carbon can be defined as a carbon body in which carbon atoms are arranged in a disordered manner without having a regular crystalline structure.

[0075] Meanwhile, while depositing graphene as a pixel definition film could be considered, graphene has the disadvantage of high electrical conductivity. Additionally, although oxidizing graphene could be considered to lower electrical conductivity, graphene oxide has the disadvantage of poor light absorption characteristics.

[0076] The pixel defining film according to the present invention may have a high absorption coefficient (K value) of about 0.27 or higher, and the pixel defining film formed under specific conditions of low pressure of about 6000 mTorr or lower and high nitrogen of about 600 sccm or higher may have a significantly high K value of about 0.30 or higher. By having such a high K value, the pixel defining film according to the present invention can absorb light coming from the outside and improve outdoor visibility.

[0077] FIG. 4 schematically illustrates an example of a PECVD device that can be used in the pixel definition film formation method according to the present invention.

[0078] Referring to FIG. 4, the illustrated PECVD device (401) is equipped with a gas supply line (S), a chamber (402), a shower head (403), a susceptor (404), an RF power source (405), and a first electrode (406).

[0079] The gas supply line (S) is connected to the chamber (402) and serves to supply process gas from outside the chamber (402) into the chamber (402). In the present invention, the process gas may be a carbon precursor. In some embodiments, the process gas may be a carbon precursor and additionally an inert gas and / or nitrogen gas.

[0080] Meanwhile, the carbon precursor is C6H 12 As shown, if it is in a liquid state at room temperature, it can be vaporized through a vaporizer and supplied into the chamber. In contrast, if the carbon precursor is in a gaseous state at room temperature, such as C3H6, it can be supplied directly into the chamber without heating.

[0081] The carbon precursor can be supplied independently into the chamber without a carrier gas, or supplied into the chamber together with an inert gas such as argon, helium, or nitrogen as a carrier gas.

[0082] A shower head (403) is provided on the upper side inside the chamber (402) and sprays process gas injected through a gas supply line (S) into the chamber.

[0083] A susceptor (404) is provided on the lower side inside the chamber (402) to which a substrate (W), such as a wafer, is loaded (supported). The susceptor (404) may be equipped with a temperature control means for heating / cooling the substrate. Additionally, the susceptor (404) may function as a ground electrode, as shown in the example in FIG. 4. A separate ground line (408) may be provided to further improve ground performance. Although not shown, the susceptor (404) itself may be configured as a second electrode (bias electrode) by connecting a high-frequency power source or a DC power source.

[0084] The first electrode (406) is electrically connected to the RF power source (405) and used as an electrode for plasma discharge within the chamber (402). In the example illustrated in FIG. 4, the showerhead (403) is electrically connected to the first electrode (406) by a connector (403a), so that the first electrode (406) and the showerhead (403) function together as a single electrode. Accordingly, RF power generated from the RF power source (405) is filtered through the RF filter (407) and applied into the process chamber (402) through the first electrode (406) and the showerhead (403). In the present invention, RF power of approximately 100 to 3000 W is generated from the RF power source (405).

[0085] The pixel definition film forming method according to the present invention may use various known PECVD devices in addition to using the PECVD device exemplified in FIG. 4.

[0086] As described above, the pixel defining film according to the present invention is formed by amorphous carbon deposition using the PECVD method. Accordingly, the method for forming a pixel defining film according to the present invention has the advantage of suppressing moisture adsorption during the process compared to the method of forming a pixel defining film using a conventional lithography process. In addition, since the pixel defining film according to the present invention is formed by amorphous carbon deposition using the PECVD method, the thickness of the film can be reduced, and thereby contribute to the thinning of the display device.

[0087] In addition, the pixel defining film formation method according to the present invention can maximize the light absorption rate while suppressing the light reflectance and light transmittance of the formed pixel defining film by controlling the amorphous carbon deposition conditions, and thereby absorb light entering from the outside to improve outdoor visibility.

[0088] Furthermore, the pixel defining film according to the present invention can serve as a substitute for a polarizer. For example, OLED display devices use polarizers to address the problem of reduced contrast ratio. However, using a polarizer blocks a portion of the light generated from the organic light-emitting layer, so it cannot prevent a decrease in brightness. However, the pixel defining film of the present invention can have light-blocking properties, thereby reducing external light reflection. Consequently, it can not only resolve the problem of reduced contrast ratio without using a polarizer but also resolve concerns regarding a decrease in brightness.

[0089] Examples

[0090] Hereinafter, the structure and operation of the present invention will be explained in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and should not be interpreted in any way as limiting the present invention.

[0091] Details not listed here can be sufficiently technically inferred by a person skilled in this field, so their explanation will be omitted.

[0092] A pixel definition film made of amorphous carbon material was deposited on the surface of a glass substrate under the process conditions listed in Table 1. The substrate temperature was 250℃.

[0093] The absorption coefficient (K value) was calculated based on reflectance and transmittance data obtained through a spectroscopic ellipsometer according to ASTM E1465 and SEMI MF1247.

[0094] [Table 1]

[0095]

[0096] Figure 5 is a graph showing the results of measuring the absorption coefficient (K) of the pixel definition film according to process pressure. Figure 5 shows the results for samples 1 and 2, where nitrogen gas was not supplied.

[0097] Referring to Table 1 and Figure 5, it can be seen that as the process pressure decreases from 6000 mTorr to 2000 mTorr, i.e., as the vacuum increases, the K value more than doubles from 0.12 to 0.27. Based on this, it can be seen that lowering the process pressure is more desirable for improving the absorption coefficient.

[0098] Figure 6 is a graph showing the results of measuring the absorption coefficient (K) of the pixel definition film according to the nitrogen gas flow rate. Figure 6 shows the results for samples 2 to 6, and the process pressure was the same at 2000 mTorr for all samples.

[0099] Referring to Table 1 and Figure 6, it can be seen that the K value of the pixel definition film increases as the nitrogen gas flow rate increases. In particular, when the nitrogen gas flow rate is 600 sccm or higher, the K value is very high, exceeding 0.3. Based on this, it can be seen that increasing the nitrogen gas flow rate is more desirable for improving the absorption coefficient.

[0100] In addition, based on Table 1, Figures 5 and 6, it can be seen that in order to improve the absorption coefficient, it is most desirable to lower the process pressure while increasing the nitrogen gas flow rate. In fact, in the case of the pixel definition films according to samples 4 to 7, when the process pressure was 3000 mTorr or less and the nitrogen gas flow rate was 600 sccm or more, a significantly high K value of 0.3 or higher was observed.

[0101] Meanwhile, referring to samples 7, 10, and 11, it can be seen that the K value tends to gradually decrease as the carbon precursor flow rate increases. Accordingly, it is desirable to supply the carbon precursor at a flow rate of 350 sccm or less, more desirable to supply it at 300 sccm or less, and most desirable to supply it at 250 sccm.

[0102] Table 2 shows the membrane densities and K values ​​of samples 5, 7 to 9.

[0103] [Table 2]

[0104]

[0105] Referring to Table 2, it can be seen that when the nitrogen flow rate is the same, the film density increases as the process pressure decreases, and the K value also increases. Based on this, it can be concluded that in order to obtain a pixel definition film with a high K value, it is necessary to increase the film density, and to achieve this, it is desirable to lower the process pressure.

[0106] Figure 7 is a graph showing the change in absorption rate according to the K value and wavelength of 400–700 nm.

[0107] Figure 8 shows the change in the average absorption rate of visible light according to the K value.

[0108] Table 3 shows the change in absorption rate according to the K value.

[0109] Based on the reflectance and transmittance data obtained through the aforementioned spectroscopic ellipsometer, the absorption rate in the visible light region (400–700 nm) was measured by wavelength (Fig. 7), and the average value was taken as the average absorption rate of visible light (Fig. 8, Table 3).

[0110] [Table 3]

[0111]

[0112] Referring to Table 3, it can be seen that the absorption rate tends to increase as the K value increases, and that the surface of the glass substrate changes to a black color as the K value increases.

[0113] Table 4 shows the changes in K values ​​and membrane stress according to inert gas and nitrogen flow rates.

[0114] In Table 4, membrane stress was measured using FLX-800 (Toho Technology), and a "-" value for membrane stress indicates that it is under compressive stress.

[0115] [Table 4]

[0116]

[0117] Referring to Table 4, a decrease in the inert gas flow rate leads to a relative increase in the proportion of nitrogen gas in the reaction chamber, and as a result, while exhibiting a similar K value, it showed the effect of reducing membrane stress.

[0118] Table 5 shows the changes in K values ​​and membrane stress according to nitrogen flow rate.

[0119] [Table 5]

[0120]

[0121] Referring to Table 5, it can be seen that when the RF power is the same at 1400W or 1100W, increasing the nitrogen gas flow rate results in an increase in the K value and a decrease in membrane stress.

[0122] Furthermore, it can be seen that increasing the nitrogen flow rate is effective for forming a pixel definition film with a high K value and low film stress at low RF power. Lower RF power can have the effect of suppressing the increase in substrate temperature during actual deposition.

[0123] When the stress on the substrate is high, the substrate bends according to the stress on the thin film, so a low stress value is required. In the case of pixel definition films, since they are generally formed as thick films of 2㎛ or more, the bending of the substrate can become severe due to film stress. Therefore, it can be concluded that it is desirable to supply nitrogen gas at a high flow rate to create low stress.

[0124] Although the present invention has been described above, it is obvious that the present invention is not limited by the embodiments disclosed in this specification, and that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention were not explicitly described while describing the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

[0125] <Explanation of Symbols>

[0126] 110: Pixel definition membrane

[0127] 120: Pixels

[0128] 201: Board

[0129] 210: Multiple electrodes

[0130] 220: Emitting layer

[0131] 401: PECVD device

[0132] S: Gas supply line

[0133] 402: Chamber

[0134] 403: Shower Head

[0135] 404: Susceptor

[0136] 405: RF Power

[0137] 406: First electrode

[0138] 407: RF filter

[0139] 408: Ground line

Claims

1. A method for forming a pixel defining film for a display device, (a) a step of placing a substrate having a plurality of electrodes formed thereon, electrically connected to a thin-film transistor at the bottom through via holes, in a reaction chamber; and (b) A method for forming a pixel defining film for a display device, comprising the step of forming a pixel defining film made of amorphous carbon material between the plurality of electrodes by a PECVD process.

2. In Paragraph 1, A method for forming a pixel defining film for a display device, wherein step (b) comprises the step of depositing an amorphous carbon film by discharging a carbon precursor under a process pressure of 6000 mTorr or less, a substrate temperature of 200 to 500°C, and an RF power of 100 to 3000W.

3. In Paragraph 2, A method for forming a pixel defining film for a display device, wherein in step (b) above, the process pressure is 3000 mTorr or less.

4. In Paragraph 2, In step (b) above, the carbon precursor is CH4, C2H2, C2H4, C2H6, C3H6, C6H 12 A method for forming a pixel defining film for a display device, comprising one or more of the following.

5. In Paragraph 2, A method for forming a pixel defining film for a display device, wherein, in step (b) above, an inert gas and a nitrogen gas are supplied into the reaction chamber together with the carbon precursor.

6. In Paragraph 5, A method for forming a pixel defining film for a display device, wherein the above nitrogen gas is supplied into the reaction chamber at a flow rate of 300 to 10,000 sccm.

7. In Paragraph 5, A method for forming a pixel defining film for a display device, wherein in step (b) above, the process pressure is 3000 mTorr or less, and the nitrogen gas is supplied into the reaction chamber at a flow rate of 600 to 5000 sccm.

8. In Paragraph 2, A method for forming a pixel defining film for a display device, wherein the carbon precursor is supplied into the reaction chamber at a flow rate of 200 to 350 sccm.

9. In Paragraph 1, A method for forming a pixel defining film for a display device, wherein, in step (b) above, the pixel defining film is formed to cover the entire thin-film transistor and a portion of the plurality of electrodes.

10. A pixel defining film for defining the position and shape of the plurality of pixels in a display device comprising a plurality of pixels, The pixel defining film above is a pixel defining film for a display device, made of amorphous carbon material.

11. In Paragraph 10, The pixel defining film above is a pixel defining film for a display device having a K value of 0.27 or higher.

12. In Paragraph 10, The pixel defining film above is a pixel defining film for a display device having a K value of 0.30 or more.

13. A substrate comprising a plurality of thin-film transistors; A plurality of electrodes disposed on a substrate comprising the plurality of thin-film transistors and electrically connected to the plurality of thin-film transistors through via holes; A pixel defining film disposed between the plurality of electrodes; and It includes a light-emitting layer disposed on the plurality of electrodes, and A display device in which the pixel defining film is made of amorphous carbon material.

14. In Paragraph 13, A display device having a pixel defining film having a K value of 0.27 or higher.

15. In Paragraph 13, A display device in which the pixel defining film has a K value of 0.30 or higher.

16. In Paragraph 13, A display device in which the pixel defining film is formed to cover the entire thin-film transistor and a portion of the plurality of electrodes.

17. In Paragraph 13, The above display device is an OLED display device, a micro LED display device, or a QLED display device.

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