KR100579175B1 - Fabricating method of OLED - Google Patents

Abstract

The present invention relates to a method of manufacturing an organic light emitting device, and more particularly, to a method of manufacturing an organic light emitting device having unit pixels in which lower layers having different thicknesses are formed. Forming an inorganic protective layer on a substrate having R, G, and B unit pixels; Forming a thickness of the inorganic protective layer for each of R, G, and B unit pixels using a halftone mask; Forming pixel electrodes for R, G, and B unit pixels on the inorganic protective layer; And forming an organic layer including R, G, and B light emitting layers on the pixel electrode.

Halftone mask, inorganic protective layer, organic light emitting device

Description

Manufacturing method of organic electroluminescent device {Fabricating method of OLED}

1 to 5 are cross-sectional views illustrating a method of manufacturing an organic light emitting diode according to an embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

100: substrate

10: halftone mask

105: buffer layer

115, 125: insulating film

135, 135a, 135b, 135c: protective layer

140: photosensitive film

160: pixel defining layer

170: counter electrode

The present invention relates to a method of manufacturing an organic light emitting device, and more particularly, to a method of manufacturing an organic light emitting device having unit pixels in which lower layers having different thicknesses are formed.

The organic light emitting device has a light emitting layer formed of an organic material between a cathode electrode and an anode electrode, and emits light from the light emitting layer when a constant current flows through the cathode electrode and the anode electrode. The organic light emitting device has a high response time with a response speed of 1 ms or less, low power consumption, and self-luminous light, so there is no problem in viewing angle, and thus it is advantageous as a moving image display medium regardless of the size of the device. In addition, low-temperature manufacturing is possible, and the manufacturing process is simple based on the existing semiconductor process technology has attracted attention as a next-generation flat panel display device in the future.

In addition, the organic light emitting device is classified into an active matrix and a passive matrix according to the driving scheme. The passive driving method is unsuitable for large display devices until now due to the problem of wiring resistance, power consumption, and driving voltage. The active driving method has lower power consumption than the passive driving method, the unit pixel forming process is simpler than the passive driving method, and has the advantage of manufacturing a high resolution panel.

In the active driving method, the organic light emitting diode is largely divided into a top emission type and a bottom emission type, and consists of two or more thin film transistors, one or more capacitors, and wirings for driving the light emitting element per unit pixel. do.

In the case of the bottom emission type, light generated in the light emitting layer is emitted toward the substrate, and a transparent conductive film is used as the anode electrode. In addition, a thin film transistor for driving the organic light emitting diode is formed on the upper surface of the substrate, and insulating layers and an inorganic protective layer formed during the manufacturing process of the thin film transistor are present under the light emitting layer of the organic light emitting diode. That is, the light generated by the organic light emitting device passes through the lower insulating layers including the inorganic protective layer.

The light generated in the light emitting layer is changed in transmittance due to the insulating film having a predetermined thickness and transmittance, thereby causing a problem that the color coordinate of the light emitted is deformed. That is, the transmittance decreases as the thickness of the insulating layers increases, and in the case of light having a short wavelength and low luminous efficiency, the transmittance decreases further, which causes deformation of color coordinates.

An object of the present invention for solving the above problems is to provide a method of manufacturing an organic light emitting device that can solve the problem of color coordinate transformation while simplifying the process using a halftone mask.

In order to achieve the above object, the present invention comprises the steps of forming an inorganic protective layer on a substrate having R, G, B unit pixels; Forming a thickness of the inorganic protective layer for each of R, G, and B unit pixels using a halftone mask; Forming pixel electrodes for R, G, and B unit pixels on the inorganic protective layer; And forming an organic layer including R, G, and B light emitting layers on the pixel electrode.

The manufacturing method may further include forming a thin film transistor including a source drain electrode, and forming a different thickness of the inorganic protective layer may be performed simultaneously with forming a via hole exposing the source or drain electrode. .

Differently forming the thickness of the inorganic protective layer for each of the R, G, and B pixel areas may be to form a thinner thickness in the order of the shorter wavelength of light and lower luminous efficiency among the R, G, and B pixels.

Differently forming the thickness of the inorganic protective layer for each of the R, G, and B pixel regions may be to form the thinnest thickness of the insulating film of the B pixel.

The thickness of the inorganic protective layer of the pixel B may be formed to be 1000 GPa or more and less than 6000 GPa.

The inorganic protective layer may be SiO 2, or SiN x.

The organic layer may include one or more layers from the group consisting of a hole injection layer, a hole transport layer, a hole suppression layer, and an electron injection layer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, lengths, thicknesses, and the like of layers and regions may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 to 5 are cross-sectional views illustrating a method of manufacturing an organic light emitting diode according to an embodiment of the present invention.

Referring to FIG. 1, a buffer layer 105 is formed on a substrate 100 in which R, G, and B pixel regions are defined. The buffer layer 105 is not necessarily formed, but it may be more preferable to form the buffer layer 105 in order to prevent impurities from flowing into the device from the substrate. The buffer layer 105 may be formed of a silicon nitride layer (SiNx), a silicon oxide layer (SiO 2), and a silicon oxynitride layer (SiOxNy).

The semiconductor layers 110 are formed on the buffer layer 105. The semiconductor layer 110 may be formed of an amorphous or crystalline silicon film, and the semiconductor layers may be formed for each of the defined R, G, and B pixel regions so that a driving thin film transistor is formed for each of the R, G, and B unit pixels. do.

In addition, a gate insulating layer 115 is formed on the semiconductor layers 110. The gate insulating film 115 is formed of a conventional insulating film, for example, a silicon oxide film (SiO ₂ ).

Gate electrodes 120 are formed on a substrate on which the gate insulating layer 115 is formed. The gate electrodes 120 are formed to correspond to the semiconductor layers of the thin film transistor in R, G, and B pixel regions. Ion implantation is performed on the semiconductor layers 110 using the gate electrode 120 as a mask. The ion implantation forms a source region and a drain region in each semiconductor layer 110, and a channel region is defined by the source region and the drain region.

 An interlayer insulating layer 125 is formed on the gate electrodes 120. A contact hole is formed in the interlayer insulating layer 125 to expose source and drain regions of the semiconductor layer 110, respectively. By stacking and patterning a conductive film on the interlayer insulating layer 130, source and drain electrodes 130a and 130b may be formed to be in contact with the exposed source and drain regions, respectively.

Referring to FIG. 2, an inorganic protective layer 135 is formed on the substrate on which the source electrode 130a and the drain electrode 130b are formed. The inorganic protective layer 135 may be formed of a silicon nitride layer (SiNx) or a silicon oxide layer (SiO 2). The inorganic protective layer 135 is more preferably formed of silicon nitride (SiNx) for the passivation effect and the external light blocking effect of the semiconductor layer.

The photosensitive film 140 is coated on the inorganic protective layer 135. The photosensitive film 140 is exposed using the halftone mask 10. The halftone mask 10 is manufactured such that the via hole region 10d and the unit pixel-specific regions 10a, 10b, and 10c all have different exposure levels. That is, the photoresist 140 is exposed at different ratios in predetermined regions so that the inorganic protective layer 135 has a different thickness for each unit pixel.

3 shows that the photosensitive film 140 exposed by using the halftone mask 10 is patterned. That is, the thickness of the photoresist film is patterned for each of the via holes, R, G, and B unit pixels of each unit pixel.

Dry etching is performed on the substrate on which the patterned photoresist film is formed. Due to the photosensitive film 140 having different thicknesses, the inorganic protective layer 135 under the photosensitive film is etched for each of the R, G, and B unit pixels to form a different thickness.

Referring to FIG. 4, a pixel electrode 170 is formed through a via hole on inorganic protective layers 135a, 135b, and 135c having different thicknesses for each unit pixel.

Forming different thicknesses of the inorganic protective layer is performed simultaneously with forming a via hole exposing the source or drain electrode. Differently forming the thickness of the inorganic protective layer for each of the R, G, and B pixel areas may be to form a thinner thickness in the order of the shorter wavelength of light and lower luminous efficiency among the R, G, and B pixels. That is, if the thickness of the inorganic protective layer of the R pixel is t _R , the thickness of the inorganic protective layer of the G pixel is t _G , and the thickness of the inorganic protective layer of the B pixel is t _B , t _R ≥ t _G ≥ t _B have.

Preferably, different thicknesses of the inorganic protective layers 135a, 135b, and 135c are formed for each of the R, G, and B pixel regions, so that the B light emission has the shortest wavelength, so that the thickness of the inorganic protective layer 135c of the B pixel is reduced. It may be to form the thinnest. The inorganic protective layer 135c of the B pixel may be formed to have a thickness of 1000 GPa or more and less than 6000 GPa.

When light generated in the organic light emitting device passes through the lower insulating films including the inorganic protective layer, the light emitted by each unit pixel passes through the insulating films having different thicknesses, and color coordinates are deformed according to the transmittance of the insulating film. The shorter the wavelength and the lower the luminous efficiency, the lower the transmittance. Therefore, the thickness of the lower inorganic protective layer of the B pixel having a short wavelength and low luminous efficiency can be made thin so that color coordinate deformation according to the transmittance of the insulating film can be controlled. That is, the wavelength of the light generated in the light emitting layer is changed due to the insulating films having a predetermined thickness and transmittance, thereby improving the color coordinate of the light deformation, thereby improving the color purity.

Subsequently, the pixel electrode 150 is formed on the inorganic protective layers 135a, 135b, and 135c for each pixel region. The pixel electrode is preferably formed of a transparent conductive film for emitting emitted light.

Referring to FIG. 5, an organic layer including emission layers R, G, and B is formed for each pixel area on the pixel electrode 150. The organic layer may include one or more layers from the group consisting of a hole injection layer, a hole transport layer, a hole suppression layer, and an electron injection layer. The counter electrode 170 is formed on the organic layer to complete the organic light emitting device.

The organic light emitting device according to the present invention is characterized in that the thickness of the insulating film including the inorganic protective layer is different from each other by using a halftone mask for each R, G, and B unit pixels.

As a result, the light emitted by each unit pixel passes through an insulating film having a predetermined different thickness, thereby improving the color coordinate deformation and improving color purity of the emitted light.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (7)

Forming an inorganic protective layer on a substrate having R, G, and B unit pixels; Forming a thickness of the inorganic protective layer for each of R, G, and B unit pixels using a halftone mask; Forming a pixel electrode for each R, G, and B unit pixels on the inorganic protective layer; and Forming an organic layer including R, G, and B light emitting layers on the pixel electrode; The method of claim 1, The manufacturing method further includes forming a thin film transistor including a source drain electrode, and forming an thickness of the inorganic protective layer differently is performed by simultaneously forming a via hole exposing the source or drain electrode. Method of manufacturing a light emitting device. The method of claim 1, Forming the thickness of the inorganic protective layer differently for each of the R, G, and B pixel areas is a method of manufacturing an organic light emitting device in which the thickness of the light among R, G, and B is shorter and the thickness is lowered in the order of low luminous efficiency. . The method of claim 3, wherein Forming the thickness of the inorganic protective layer differently for each of the R, G, and B pixel areas forms the thinnest thickness of the insulating film of the B pixel. The method of claim 4, wherein The thickness of the inorganic protective layer of the pixel B is to be formed to more than 1000 GPa to less than 6000 GPa. The method of claim 1, The inorganic protective layer is SiO 2, or SiN x A method of manufacturing an organic light emitting device. The method of claim 1, The organic layer is a method of manufacturing an organic light emitting device comprising at least one layer from the group consisting of a hole injection layer, a hole transport layer, a hole suppression layer, and an electron injection layer.

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