KR20170129512A - Organic light emitting display device and method for fabricating the same - Google Patents

Abstract

The present invention relates to an organic light emitting display apparatus capable of alleviating a difference between the thickness of an overcoat layer remaining on red, green and blue color filters and the thickness of an overcoat layer remaining on a white color filter, and a manufacturing method thereof. The organic light emitting display apparatus according to an aspect of the present invention comprises an interlayer insulating film having openings in a position corresponding to the remaining sub-pixel areas excluding a white sub-pixel area among a plurality of sub-pixel areas on the whole surface of a substrate including a thin film transistor.

Description

Technical Field [0001] The present invention relates to an organic light emitting diode (OLED) display device and a method of manufacturing the same,

The present invention relates to a display device, and more particularly, to a display device that mitigates a difference between a thickness of an overcoat layer remaining in red, green, and blue sub-pixel areas and a thickness of an overcoat layer remaining in a white sub- And a method of manufacturing the same.

BACKGROUND ART Demands for a display device for displaying an image have been increasing in various forms as an information society has developed. Recently, a liquid crystal display device (LCD), an organic light emitting display device (OLED: Organic Light Emitting Display Device ) And the like are being utilized. Such various display devices are provided with display panels corresponding thereto.

The display panel included in the display device may be one of a plurality of display panels formed on one substrate. That is, according to various process procedures, after a device, a signal line, or a power line constituting pixels in one substrate is formed in a display panel unit, a substrate is cut in a display panel unit by using a scribe equipment To create multiple display panels.

The OLED display according to the related art will be described with reference to FIGS. 1 and 2. FIG.

1 is a cross-sectional view schematically showing an OLED display according to a related art.

Referring to FIG. 1, a plurality of pixel regions constituting a display panel (not shown) of an organic light emitting display according to the related art includes four color sub-pixel regions, And a second sub-pixel region that is adjacent to the first sub-pixel region and includes a sub-pixel region in which no color filter is formed.

Three first sub-pixel regions are referred to as red / green / blue sub-pixel regions 51, 55 and 57, and one second sub-pixel region is referred to as a white sub-pixel region 53.

The red color filter 21 is located in the red sub-pixel region 51 constituting the first sub-pixel region, the blue color filter 25 is located in the green sub-pixel region 55, And the blue color filter 27 is located on the light receiving surface 57.

The white sub-pixel region 53 constituting the second sub-pixel region is composed of two color filters, for example, a red color filter 21, a green color filter 25 and a blue color filter 27, for example, a red color filter 21 ) And the green color filter 25, and the color filter is not formed in the white sub-pixel region 53.

A display panel (not shown) includes a plurality of pixel regions in which a plurality of organic light emitting devices are disposed, and a plurality of thin film transistors having a plurality of thin film transistors for driving the plurality of organic light emitting devices.

A buffer layer 13, an activation layer (not shown), a gate insulation layer (not shown), a gate electrode (not shown), and an interlayer dielectric layer (ILD) 15 are formed on the substrate 11, A source / drain electrode 17 electrically connected to an activation layer (not shown) is formed through a gate electrode 15.

A passivation film 19 is formed on the entire surface of the substrate including the source / drain electrodes 17 (not shown).

Green, and blue color filters 21, 25, and 27 are formed on the passivation film 19 located in the red / green / blue sub-pixel regions 51, 55, and 57, respectively. At this time, a color filter is not formed on the white sub-pixel region 53.

An overcoat layer 31 is formed on the entire surface of the passivation film 19 including the red, green, and blue color filters 21, 25, and 27. At this time, the first thickness W1 of the overcoat layer 31 on the red color filter 21 is formed to be thinner than the second thickness W2 of the overcoat layer 31 located in the white sub-pixel region 53. [

Although not shown in the figure, a pixel electrode (not shown), a bank (not shown), an organic light emitting layer (not shown) And a cathode electrode (not shown) is formed on the organic light emitting layer (not shown).

1, red, green and blue sub-pixels 51, 52 are formed by the color filter photoresist (PR) step at the time of photo processing of the overcoat 31 without using a white photoresist, 55 and 57 and the thickness of the overcoat layer 31 located in the white sub-pixel region 53 are different from each other.

In the structure of the overcoat layer 31 and the passivation film 19, after the photolithography process of the overcoat layer 31, during the ashing process by a halftone mask (H / T) process, Since the overcoat layer 31 is partly removed at the time of forming the drain contact hole for connecting the electrodes, the thickness of the overcoat layer 31 is also thinned so that the red, green, and blue sub pixel regions 51, 55, If the thickness of the overcoat layer 31 is different, the process margin is disadvantageous.

2 is a view showing an overcoat layer in a red sub-pixel region and a white sub-pixel region constituting a display panel of an organic light emitting display according to a related art.

As shown in "A" of FIG. 2, the current red photoresist 21 is the thickest so that the overcoat layer 31 remaining on it is the thinnest, so that the process margin is reduced by the red sub- Can be determined. In particular, when the process margin of the thickness of the overcoat layer 31 is insufficient, a short failure may occur between the anode electrode and the cathode electrode in the cell.

If the wet etching (W / E) of the pixel due to the shortage of the process margin of the thickness of the remaining overcoat layer 31 is increased, the bias increases. 2, when the overcoat layer 31 is lost and the red pigment 21 is exposed, the bias at the time of wet etching of the pixel is increased, thereby exposing the taper region of the pixel outside the bank .

In addition, since the taper structure of the pixel is implemented by an inverse taper so that the bank is covered, the pixel is wet-etched so as to be out of the bank. Therefore, short-circuit between the anode electrode and the cathode electrode after deposition of the organic light- A dark spot is generated.

It is an object of the present invention to provide an organic light emitting display and a method of manufacturing the same that can alleviate the difference between the thickness of the overcoat layer remaining on the red, green, and blue color filters and the thickness of the overcoat layer remaining on the white color filter will be.

In order to accomplish the above object, in one aspect, the present invention provides a method of manufacturing a thin film transistor, comprising: providing a plurality of sub-pixel regions on a front surface of a substrate including a thin film transistor, Green, and blue sub-pixel regions, and a plurality of red, green, and blue color filters disposed in the red, green, and blue sub-pixel regions, respectively, and a plurality of sub- An organic light emitting display device including an overcoat layer is provided.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming openings in an interlayer insulating film at positions corresponding to remaining sub pixel regions excluding a white sub pixel region among a plurality of sub pixel regions; Forming red, green, and blue color filters in each of the openings located in the red, green, and blue color filters, and forming an overcoat layer on the entire surface of the substrate including red, green, and blue color filters .

The organic light emitting display and the method of manufacturing the same according to the present invention have the following effects.

In the present invention, the openings for inserting the red, green, and blue color filters are designed in the interlayer insulating films of the red, green, and blue sub-pixel regions except the white sub-pixel region so that the step (i.e., height) The thickness of the overcoat layer remaining on the red, green, and blue color filters can be increased as much as the thickness of the insulating film.

In particular, the present invention can mitigate the difference in overcoat layer thicknesses by red, white, blue, and green subpixel areas after the photolithography process of the overcoat layer, thereby increasing the thickness margin of the remaining overcoat layer.

In addition, the present invention can form openings for inserting red, green, and blue color filters in the interlayer insulating films of the red, green, and blue sub-pixel regions except the white sub-pixel region without additional masking process. Can be simplified.

Moreover, the present invention prevents the overcoat layer on the red, green, and blue color filters from being lost, as the red, green, and blue color filters are within the openings, even if some thickness of the overcoat layer is removed by the ashing process.

1 is a schematic cross-sectional view of an organic light emitting display according to the related art.
FIG. 2 is a schematic enlarged view of an overcoat layer formed in a red sub-pixel region and a white sub-pixel region of an OLED display according to a related art.
FIG. 3 is a schematic view of an organic light emitting diode display according to the present invention.
4 is a schematic circuit configuration diagram of an organic light emitting diode display according to the present invention.
FIG. 5 is a diagram schematically showing red, white, green, and blue sub-pixel regions constituting each pixel of a display panel of an organic light emitting diode display according to the present invention.
FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5, and is a cross-sectional view illustrating a thin film transistor unit and a pixel unit of the organic light emitting diode display according to the present invention.
7 is a cross-sectional view illustrating a pixel portion of an OLED display according to an exemplary embodiment of the present invention.
8 is a process flow diagram of an organic light emitting diode display according to the present invention.
9A to 9P are cross-sectional views illustrating a manufacturing process of the organic light emitting diode display according to the present invention.

Hereinafter, some embodiments of the present invention will be described with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.

3 is a simplified view of a display device according to embodiments of the organic light emitting display of the present invention.

3, the OLED display 100 includes a plurality of first lines VL1 to VLm formed in a first direction (e.g., a vertical direction) and a plurality of first lines VL1 to VLm in a second direction A display panel 110 on which a plurality of second lines HL1 to HLn are formed, a first driver 120 for supplying a first signal to a plurality of first lines VL1 to VLm, A second driver 130 for supplying a second signal to the first and second lines HL1 to HLn and a timing controller 140 for controlling the first and second drivers 120 and 130.

The display panel 110 is provided with a plurality of first lines VL1 to VLm formed in a first direction (e.g., a vertical direction) and a plurality of second lines HL1 to HLn formed in a second direction (e.g., A plurality of pixels (P) are defined according to the intersection of the pixels.

Each of the first driver 120 and the second driver 130 may include at least one driver IC for outputting a signal for displaying an image.

A plurality of first lines VL1 to VLm formed in the first direction on the display panel 110 are formed in a vertical direction (first direction) to transmit a data voltage (first signal) And the first driver 120 may be a data driver for supplying the data voltage to the data line.

A plurality of second lines HL1 to HLn formed in the second direction on the display panel 110 are formed in a horizontal direction (second direction) to form a gate signal (first signal) And the second driver 130 may be a gate driver for supplying a scan signal to the gate line.

A pad portion is formed on the display panel 110 to connect the first driver 120 and the second driver 130 to each other. When the first driver 120 supplies a first signal to the plurality of first lines VL1 through VLm, the pad unit transmits the first signal to the display panel 110 and the second driver 130 similarly applies a plurality of second lines HL1 to HLn), and transmits the second signal to the display panel (110). Therefore, the pad portion can be formed together in the step of forming the regions of the pixels of the display panel 110. [

4 is a circuit diagram of a pixel structure to which embodiments of the organic light emitting diode display of the present invention are applied.

4, each of the plurality of pixels of the display panel 110 applied to the organic light emitting display of the present invention includes an organic light emitting diode (OLED), a driving transistor DT, a first transistor T1, A second transistor T2, a storage capacitor Cstg, and the like.

Each transistor is a thin film transistor (TFT).

In the organic light emitting diode OLED, a first electrode (e.g., an anode or a cathode) is connected to the driving transistor DT and a second electrode (e.g., a cathode or anode) supplies a ground voltage VSS or EVSS. Lt; / RTI >

The driving transistor DT is a transistor for driving the organic light emitting diode OLED and is controlled by a voltage applied to a second node N2 which is a gate node and is driven from a driving voltage line DVL The organic light emitting diode OLED emits light by applying a voltage (VDD: Driving Voltage or EVDD) to the third node N3 and supplying current to the organic light emitting diode OLED.

The first transistor T1 is connected between a reference voltage supply node Nref to which a reference voltage Vref is supplied and a first node N1 of the driving transistor DT. And is applied to the first node N1 of the driving transistor DT by a reference voltage Vref applied to the reference voltage supply node Nref and is controlled by the scan signal SCAN supplied through the line GL. have.

The second transistor T2 is a transistor connected between the data line DL and the second node N2 of the driving transistor DT and is connected to the scan signal supplied to the gate node of the first transistor T2 SCAN to the gate node and supplies the data voltage Vdata supplied through the data line DL to the second node N2 which is the gate node of the driving transistor DT.

The storage capacitor Cstg is connected between the first node N1 and the second node N2 of the driving transistor DT and serves to maintain the voltage during one frame.

As described above, the first transistor T1 and the second transistor T2 are simultaneously supplied with the scan signal SCAN through one gate line GL. Therefore, the gate nodes of the first transistor T1 and the second transistor T2 are connected to each other in a circuit.

On the other hand, although all transistors are described as N type in the present specification and drawings, all the transistors or some transistors may be designed as P type according to the circuit design method.

5 is a schematic plan view of an OLED display according to the present invention.

Referring to FIG. 5, each of the plurality of pixel regions constituting the display panel 110 is composed of four color sub-pixel regions, and each pixel region includes three first sub-pixel regions Pixel region and a second sub-pixel region which is located between the two first sub-pixel regions and which is a sub-pixel region in which no color filter is formed.

Three first sub-pixel regions are referred to as red / green / blue sub-pixel regions 151, 155 and 157, and one second sub-pixel region is referred to as a white sub-pixel region 153.

6 is a schematic cross-sectional view of an OLED display according to an embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of an overcoat layer stacked on top of red, green, and blue color filters, according to one embodiment of the present invention.

Referring to FIG. 6, an organic light emitting display according to the present invention including a display portion and a non-display portion defined around the display portion includes a plurality of pixel regions P in which a plurality of organic light emitting devices are disposed, And a transistor region T provided with a plurality of thin film transistors for driving a plurality of organic light emitting elements.

Each of the plurality of pixel regions constituting the display panel is constituted by four color sub-pixel regions, and each pixel region includes three first sub-pixel regions each including a sub-pixel region in which a color filter is located, And a second sub-pixel region which is located between the sub-pixel regions and is a sub-pixel region in which no color filter is formed.

Three first sub-pixel regions are referred to as red / green / blue sub-pixel regions 151, 155 and 157, and one second sub-pixel region is referred to as a white sub-pixel region 153.

The red color filter 121r is located in the red sub-pixel region 151 constituting the first sub-pixel region, the blue color filter 125g is located in the green sub-pixel region 155, And the blue color filter 127b is located in the color filter 157.

The red color filter 121r, the blue color filter 125g, and the green color filter 127b corresponding to the color filters of a specific color pass only the wavelength of light corresponding to the corresponding color.

The white sub-pixel region 153 constituting the second sub-pixel region is composed of two color filters, for example, a red color filter 121r, a green color filter 125g and a blue color filter 127b, The white color filter region 121r and the green color filter 125g or between the green color filter 125g and the blue color filter 127b and the color filter is not formed in the white sub-

(Not shown) for transmitting a driving voltage, a data line (not shown) for transmitting a driving voltage, and a Vref (not shown) for transmitting a reference voltage are formed in the white sub-

Line or the like may be formed.

A data line (not shown) is connected to a switching transistor (Swithcing Transistor), and a Vref (not shown) line is connected to a sensing transistor. Yes. Since the present invention is not limited to a specific transistor structure, various transistor structures can be applied.

Green, and blue color filters 121r, 125g, and 127b as shown in FIG. 6 below on a region where EL (Electroluminescence) is emitted, a display device using an organic material (White EL) Green / blue (R, G, B).

In the area where the color filters are laminated, one color filter layer is stacked only on an area where the organic light emitting layer (not shown) emits light, and the light passing through the color filter is reflected by the color filters other than the wavelength band And blocks the remaining wavelength bands except for the band to implement a specific color.

(Red), B (blue), G (green), and W (white) in the process of describing red / blue / green / white.

6, a buffer layer 102, an activation layer 103, a gate insulating film 105, a gate electrode 107, and a gate electrode 107 are formed on the entire surface of the substrate 101 including the transistor region T and the pixel region P. [ An interlayer dielectric layer (ILD) 109 is formed.

Active layer contact holes 113a and 113b for connecting the activation layer 103 and the source / drain electrodes 117a and 117b are formed in the interlayer insulating film 109, and the white sub- Green, and blue color filter insertion openings 115r, 115g, and 115b are formed in the interlayer insulating film 109 located in the red, green, and blue sub pixel regions 151, 155, and 157, respectively.

A source electrode 117a and a drain electrode 117b connected to the source region 103b and the drain region 103c of the active layer 103 are formed on the interlayer insulating film 109 through the active layer contact holes 113a and 113b do.

Red, green, and blue color filters 121f, 125g, and 127b are formed in the openings 115r, 115g, and 115b for inserting the red, green, and blue color filters.

An overcoat layer 131 is formed on the entire surface of the substrate including the source / drain electrodes 117a and 117b.

Pixel electrodes (or anode electrodes) 133 and an organic emission layer 137 are formed on the red, white, green, and blue sub-pixel regions 151, 153, 155, and 157 of the substrate 101 And a cathode electrode 139 is formed on the organic light emitting layer 137. Red / green / blue color filters 121r, 125g, and 127b are formed in the red, green, and blue sub-pixel regions 151, 155 and 157 forming the first sub- No separate color filter is formed.

The organic light emitting display according to the present invention having such a structure will be described in detail with reference to FIGS. 6 and 7. FIG.

6, a buffer layer 102 is formed on a substrate 101 made of a glass or plastic material and a thin film transistor (TFT) and an organic light emitting element E are formed on the buffer layer 102 .

A buffer layer 102 is formed on the substrate 101 and an active layer 103 formed of a semiconductor material is provided on the buffer layer 102. The active layer 103 formed on the substrate 101 may be formed of an inorganic semiconductor or an organic semiconductor. The source region 102b and the drain region 102c may be doped with an n-type impurity or a p- And a channel region 103a connecting the source region 103b and the drain region 103c.

A gate insulating film 105 is formed on the active layer 103 and a gate electrode 107 is formed on the gate insulating film 105. At this time, the gate electrode 107 is connected to a gate line (not shown) for applying on / off signals of the thin film transistor TFT. The gate electrode 107 may be formed of a conductive metal film such as MoW, Al, Cr, or Al / Cu. However, the gate electrode 107 is not limited thereto. Various conductive materials such as a conductive polymer may be used. The gate electrode 107 is formed so as to cover an area corresponding to the channel region 103a of the active layer 103. [

An interlayer insulating film 109 is formed on the entire surface of the substrate so as to cover the gate electrode 107. The interlayer insulating film 109 is provided with an active layer contact hole 103a for exposing the source region 103b and the drain region 103c in the active layer 103 113a, and 113b are formed.

In the interlayer insulating film 109 located in the red, green and blue sub-pixel regions 151, 155 and 157 of the interlayer insulating film 109, red, green, and blue are formed to expose the buffer layer 102 under the interlayer insulating film. The color filter insertion openings 115r, 115g, and 115b are formed. Particularly, the red color filter insertion opening 115r corresponds to the red sub pixel region 151, the green color filter insertion opening 115g corresponds to the green sub pixel region 155, And the opening 115r corresponds to the blue sub-pixel region 157. [

However, no opening is formed in the interlayer insulating film 109 located in the white sub-pixel region 153. [ As described above, the red, green, and blue color filter insertion openings 115r, 115g, and 115b located in the red, green, and blue sub pixel regions 151, 155, and 157 except for the white sub- The step (that is, the height) of the red, green, and blue color filters 121r, 125g, and 127b can be lowered by the thickness of the interlayer insulating film 109 by designing as an interlayer insulating film hole.

The source electrode 117a and the drain electrode 117b are connected to the source region 103b and the drain region 103c through the active layer contact holes 113a and 113b on the interlayer insulating film 109, (Not shown) extending from the gate line (not shown) and crossing the gate line (not shown).

Although not shown in the drawing, a VDD line for transmitting a driving voltage and a Vref line for transmitting a reference voltage may be formed on the interlayer insulating film 109 as well.

A passivation film 119 is formed on the entire surface of the substrate including the source electrode 117a and the drain electrode 117b. The passivation film 119 may serve as a protective film for protecting the thin film transistor (TFT), or may serve as a planarization film for planarizing the upper surface.

On the other hand, a red color filter 121r, a green color filter 125g, and a blue color filter 127b are formed on the passivation film 119 in the openings 115r, 115g, and 115b.

7, an overcoat layer 131 having a planarizing function is formed on the entire surface of the passivation film 119 including the red color filter 121a, the green color filter 125g and the blue color filter 127b. Is formed. The first thickness W1 of the overcoat layer 131 on the red color filter 121r located in the red sub pixel area 151 among the thicknesses of the overcoat layer 131 is smaller than the first thickness W1 of the overcoat layer 131 located in the white sub pixel area 153. [ The second thickness W2 of the layer 131 can be maintained.

This is because the red color filter 121r is formed in the opening 115r formed in the interlayer insulating film 109 so that the thickness margin of the overcoat layer 131 remaining on the red color filter 121r is increased, The thickness of the overcoat layer 131 located in the sub-pixel region 153 is substantially kept.

The present invention is not limited to this but the present invention is not limited to this and may be applied to the overcoat layer 131 remaining on the green color filter 125g and the blue color filter 127b. The thickness of the overcoat layer 131 located in the white sub-pixel region 151 can be maintained substantially similar to the thickness of the overcoat layer 131 located in the white sub-

A drain contact hole 132 exposing the drain electrode 117b of the thin film transistor is formed in the overcoat layer 131 and the passivation film 119 below the overcoat layer 131. [

An anode electrode electrically connected to the drain electrode 117b of the thin film transistor through the drain contact hole 132 in the red, white, green and blue sub-pixel regions 151, 153, 155 and 157 is formed on the overcoat layer 131, (133) is formed. The anode electrode 133 is located corresponding to the red, white, green, and blue sub pixel regions 151, 153, 155, and 157.

The anode electrode 133 may be formed of a transparent electrode and a reflective electrode. When used as a transparent electrode, the anode electrode 133 may be formed of ITO, IZO, ZnO, or In ₂ O _3. When used as a reflective electrode, Ag, Mg , ITO, IZO, ZnO, or In ₂ O ₃ may be formed on the reflective film after forming a reflective film using a metal such as Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a compound thereof.

A bank layer 135 made of an organic material such as polyimide (PI) is formed to cover the edge portion of the anode electrode 133. The banks 135 define the OLED emission regions, that is, the respective sub-pixel regions, and also serve to insulate the sub-pixel regions. As the material forming the bank 135, an organic material such as polyimide (PI), and in some cases, an inorganic material may be applied.

An organic light emitting layer 137 is formed on the entire surface of the substrate including the anode electrode 133 and the bank 135. The organic light emitting layer 137 includes a light emitting layer (not shown). At this time, the present invention is not necessarily limited to such a structure, and the structure of various organic light emitting display devices can be directly applied.

When a low molecular weight organic light emitting layer is used, a hole injecting layer (HIL), a hole transporting layer (HTL), a light emitting layer (EML), and a light emitting layer (EML) may be used as the organic light emitting layer 137. [ An electron transport layer (ETL), and an electron injection layer (EIL) may be laminated in a single or a composite structure. Also usable materials are copper phthalocyanine (CuPc), N, N-di (naphthalen-1-yl) -N, N'- (NPB), tris-8-hydroxyquinoline aluminum (Alq3), and the like. These low molecular weight organic light emitting layers are formed by a vacuum deposition method.

In the case of the polymer organic light emitting layer, a hole transport layer (HTL) and a light emitting layer (EML) may be generally provided. In this case, PEDOT is used as the hole transport layer and a poly-poly-phenylenevinylene (PPV) A polymer organic material such as polyfluorene or the like can be used and it can be formed by screen printing or ink jet printing.

The organic light emitting layer is not necessarily limited to the organic light emitting layer, and various embodiments may be applied.

On the other hand, a cathode electrode 139 is formed on the organic light emitting layer 137. The cathode electrode 139 may be formed of a transparent electrode or a reflective electrode. When the cathode electrode 139 is used as a transparent electrode, a metal having a low work function, that is, Li, Ca, LiF / Ca, LiF / An auxiliary electrode layer or a bus electrode line may be formed thereon by a transparent electrode forming material such as ITO, IZO, ZnO, or In ₂ O ₃ on the substrate. When it is used as a reflective electrode, Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg,

The anode electrode 133, the cathode electrode 139, and the organic light emitting layer 137 between these electrodes constitute the organic light emitting element E. The anode electrode 133 is electrically connected to the drain electrode 117b of the thin film transistor TFT by an electric field. The organic electroluminescent device E emits red, green, And the cathode electrode 139 is provided so as to cover all the pixels to supply a minus (-) power.

The anode electrode 133 and the cathode electrode 139 are insulated from each other by the organic light emitting layer 137 and a voltage having a different polarity is applied to the organic light emitting layer 137 to cause the organic light emitting layer 137 to emit light do.

As described above, according to the present invention, the openings for inserting the red, green, and blue color filters are designed in the interlayer insulating films of the red, green, and blue sub-pixel regions except for the white sub-pixel region, Can be increased by the thickness of the interlayer insulating film, thereby increasing the thickness margin of the overcoat layer remaining on the red, green, and blue color filters.

In particular, the present invention can mitigate the difference in overcoat layer thicknesses by red, white, blue, and green subpixel areas after the photolithography process of the overcoat layer, thereby increasing the thickness margin of the remaining overcoat layer.

The process of fabricating the OLED display according to the present invention will now be described with reference to FIG.

8 is a process flow diagram of an organic light emitting diode display according to the present invention.

Referring to FIG. 8, as a first step 811, an active layer is formed on a substrate on which a buffer layer (not shown) is formed.

Then, as the second and third steps (812, 813), a gate insulating film and a gate are formed on the active layer.

Next, as a fourth step 814, an interlayer insulating film is formed over the entire surface of the substrate including the gate.

Then, in a fifth step 815, active layer contact holes for connecting the active layer and the source / drain electrodes are formed in the interlayer insulating film located in the thin film transistor portion in each sub pixel region, Green, and blue color filter openings are formed in the interlayer insulating film located in the red (R), green (G), and blue sub-pixel regions. At this time, the step (i.e., height) of the white sub-pixel region is increased by the thickness of the interlayer insulating film, thereby increasing the thickness margin of the remaining overcoat layer formed in the subsequent process.

Next, as a sixth step 816, a source electrode and a drain electrode connected to the source region and the drain region of the active layer are formed on the interlayer insulating film through the active layer contact hole.

Then, as a seventh step 817, a passivation film is formed on the interlayer insulating film including the source electrode and the drain electrode. At this time, the passivation film is also formed in the color filter insertion opening in the interlayer insulating film located in the red (R), green (G), and blue sub pixel regions as well as the white sub pixel region.

Next, as an eighth step 818, red, green, and blue color filters are formed on the passivation film in the color filter insertion opening of the interlayer insulating film located in the red (R), green (G) .

Then, as a ninth step 819, an overcoat layer is formed on the entire surface of the passivation film including the red, green, and blue color filters.

Next, as a tenth step (820), a drain contact hole is formed in the overcoat layer and the passivation film below the overcoat layer. Drain contact holes are formed in the overcoat layer and the passivation film located in the thin film transistor portion in the red (R), green (G), and blue (B) sub pixel regions as well as the white sub pixel region.

Then, in an eleventh step (821), on the overcoat layer, an anode (not shown) electrically connected to the drain electrode in the thin film transistor portion in the red (R), green (G) Thereby forming an anode electrode. At this time, the anode electrode is separately formed in the red (R), green (G), and blue sub-pixel regions as well as the white sub-pixel region.

Next, as a twelfth step (812), in the sub-pixel region adjacent to the overcoat layer including the edge portion of the anode electrode separately formed in the red (R), green (G), and blue sub- To form a bank for defining the bank.

Then, in the thirteenth step 813, an organic light emitting layer is formed on the entire surface of the overcoat layer including the anode electrode and the bank separately formed in the red (R), green (G), and blue sub pixel regions as well as the white sub pixel region do.

Next, as a fourteenth step 814, a cathode electrode is formed on the entire surface of the organic light emitting layer, thereby completing the manufacturing process of the organic light emitting display according to the present invention.

A method for fabricating an organic light emitting diode display according to the present invention manufactured by such a process sequence will be described in detail with reference to FIGS. 9A to 9P.

9A to 9P are cross-sectional views illustrating a manufacturing process of the organic light emitting diode display according to the present invention.

Although not shown in the figure, each of a plurality of pixel regions constituting a display panel (not shown in Fig. 3) 110 is constituted by four color sub-pixel regions, and each pixel region includes a sub- And a second sub-pixel region that is adjacent to the two first sub-pixel regions and includes a sub-pixel region in which no color filter is formed.

Three first sub-pixel regions are referred to as red / green / blue sub-pixel regions 151, 155 and 157, and one second sub-pixel region is referred to as a white sub-pixel region 153.

The white sub-pixel region 153 constituting the second sub-pixel region is composed of two color filters, for example, a red color filter 121r, a green color filter 125g and a blue color filter 127b, The green color filter 125g and the green color filter 125g and the blue color filter 127b and the color filter is not formed in the white sub pixel region 153. [

(Not shown), a data line (not shown), and a Vref (not shown) for transmitting a reference voltage are formed in the white sub-pixel region 153,

Line or the like may be formed.

A data line (not shown) is connected to a switching transistor (Swithcing Transistor), and a Vref (not shown) line is connected to a sensing transistor. Yes. Since the present invention is not limited to a specific transistor structure, various transistor structures can be applied.

9A, a substrate 101 in which a display region (not shown) and a non-display region (not shown) are defined outside the display region is first prepared. At this time, the substrate 101 is made of a flexible glass substrate or a plastic material having flexible characteristics so that the flexible organic electroluminescent device OLED can maintain its display performance even if bent like paper.

Then, a buffer layer 102 made of silicon oxide (SiO ₂ ) or silicon nitride (SiN x), which is an inorganic insulating material, is formed on the substrate 101. The reason for forming the buffer layer 102 below the active layer 103 formed in the subsequent process is that the active layer 103 is formed by the release of the alkali ions from the inside of the substrate 101 during the crystallization of the active layer 103, In order to prevent deterioration of characteristics of the semiconductor device.

9B, the driving region (not shown) and the switching region (not shown) are formed in respective pixel regions (not shown in FIG. 3) in a display region (not shown) above the buffer layer 102, And a central portion of the first region 103a and a second region 103b and 103c doped with a high concentration of impurities on both sides of the first region 103a. The active layer 103 is formed.

9C, a gate insulating film 105 is formed on the active layer 103, and a gate insulating film 105 is formed on the gate insulating film 105 in the driving region (not shown) and the switching region (not shown) A gate electrode 107 is formed corresponding to the first region 103a of each active layer 103. [ At this time, a gate wiring (not shown) extending in one direction is formed on the gate insulating layer 105, which is connected to the gate electrode 107 formed in the switching region (not shown).

The gate electrode 107 and the gate wiring (not shown) may be formed of a first metal material having low resistance characteristics such as aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum ) And molybdenum (MoTi) and may have a single layer structure, or may be formed of two or more of the first metal materials to have a double layer structure or a triple layer structure. In the drawing, the gate electrode 107 and the gate wiring (not shown) have a single-layer structure as an example.

Next, referring to Fig. 9d, the gate electrode 107 with the gate wiring (not shown) over the display region isolated in the front material, such as a silicon oxide inorganic insulating material (SiO ₂₎ or layers made of silicon nitride (SiNx) An insulating film 109 is formed.

9E, the interlayer insulating film 109 located in the thin film transistor portion T is selectively patterned by a photolithography process technique so that the first and second regions 103a and 103a of the respective active layers, The active layer contact holes 113a and 113b exposing the second regions 103b and 103c are formed.

The red (R), green (G), and blue (B) sub pixel regions 151, 155, and 157 are formed in the active layer contact holes 113a and 113b, The color filter insertion openings 117r, 117g, and 117b are formed at the same time so that the red, green, and blue color filters can be inserted into the interlayer insulating film 109. At this time, the step (that is, height) of the white (W) sub pixel region 153 is increased by the thickness of the interlayer insulating film 109, for example, about 4000-6000 Å to form the overcoat layer Can be increased.

Next, although not shown in the drawing, a gate line (not shown) is formed on the interlayer insulating film 109 including the active layer contact holes 113a and 113b to define the pixel region P, To form a layer (not shown).

At this time, the second metal material layer (not shown) may include aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum (MoTi), chromium (Cr) Ti) may be used.

Then, a data wiring (not shown) for selectively defining the second metal material layer (not shown) to cross the gate wiring (not shown) and defining the pixel region P, (Not shown). At this time, the power supply wiring (not shown) may be formed on the layer on which the gate wiring (not shown) is formed, that is, on the gate insulating film and spaced apart from the gate wiring (not shown).

Through the active layer contact holes 113a and 113b, the interlayer insulating film 109 is separated from the driving region (not shown) and the switching region (not shown) The source electrode 117a and the drain electrode 117b of the second metal material, which are in contact with the first and second regions 103b and 103c and are the same as the data line (not shown), are simultaneously formed.

Although the data wiring (not shown) and the source electrode 117a and the drain electrode 117b both have a single layer structure in the figure, these components may have a double layer structure or a triple layer structure.

At this time, the active layer 103, the gate insulating film 105, the gate electrode 107, the interlayer insulating film 109, and the source (not shown) which are sequentially stacked in the driving region (not shown) and the switching region The electrode 117a and the drain electrode 117b constitute a driving thin film transistor (not shown in Fig. 4, DT).

Although not shown in the drawing, switching thin film transistors (not shown in FIG. 4, T1 and T2 in FIG. 4) having the same lamination structure as the driving thin film transistor DT are also formed in the switching region (not shown). At this time, the switching thin film transistor (not shown) is electrically connected to the driving thin film transistor DT, the gate wiring (not shown) and the data wiring (not shown). That is, the gate wiring (not shown) and the data wiring (not shown) are respectively connected to a gate electrode (not shown) and a source electrode (not shown) of a switching thin film transistor The drain electrode (not shown) of the driving TFT DT may be electrically connected to the gate electrode 107 of the driving TFT DT.

The driving thin film transistor DT and the switching thin film transistor (not shown) applied to the organic light emitting display according to the present invention include a polysilicon active layer 103 and a top gate type However, the driving switching thin film transistor DT and the switching thin film transistor (not shown) may be formed of a bottom gate type having an active layer of amorphous silicon.

When a driving thin film transistor (not shown) and a switching thin film transistor (not shown) are formed of a bottom gate type, the laminated structure is separated from the active layer of the gate electrode / gate insulating film / pure amorphous silicon, And a source electrode and a drain electrode which are spaced apart from the semiconductor layer made of the contact layer. In this case, the gate wiring is formed to be connected to the gate electrode of the switching thin film transistor in a layer in which the gate electrode is formed, and the data wiring may be formed to be connected to the source electrode in a layer in which a source electrode of the switching thin film transistor is formed.

In the present invention, a driving thin film transistor (not shown) and a switching thin film transistor (not shown) are collectively referred to as a thin film transistor.

9G, the source electrode 117a and the drain electrode 117b and the color filter insertion openings 115r, 115g, and 115b constituting the thin film transistor are formed on the entire surface of the interlayer insulating film 109 by the passivation film 119 ). As the passivation film 119, an insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiN x), which is an inorganic insulating material, may be used.

The passivation film 119 is formed in the interlayer insulating film located in the red (R), green (G) and blue sub-pixel regions 151, 155 and 157 as well as the white sub- (115r, 115g, 115b). Therefore, the step (i.e., height) of the white sub-pixel region 153 becomes higher by the thickness of the interlayer insulating film 109, and the thickness margin of the remaining overcoat layer 131 formed in the subsequent process can be increased accordingly.

9H, a photoresist PR for a red color filter is applied to the entire surface of the passivation film 119, and then a photoresist PR for a red (R) color filter is formed through a photolithography process Is patterned to form the red color filter 121r in the red color filter insertion opening 115r located in the red (R) sub pixel region 151. [

9H, a green (G) color filter photoresist PR is applied to the entire surface of the passivation film 119, and then a photoresist PR for a green color filter is patterned through a photolithography process technique The green color filter 125g is formed in the green color filter insertion opening 115g located in the green (G) sub pixel region 155. [

9H, a blue (B) color filter photoresist PR is applied on the entire surface of the passivation film 119, and then a photoresist PR (blue Is patterned to form the blue color filter 127b in the blue color filter insertion opening 115b located in the blue (B) sub pixel region 157. [

As described above, the red, green, and blue (B) color filter forming processes are sequentially performed to form red (R), green (G), and blue Green, and blue color filters 121r, 125g, and 127b are formed on the passivation film 119 in the red, green, and blue color filter insertion openings 115r, 115g, and 115b of the interlayer insulating film 109, do.

9I, an overcoat layer 131 is formed on the entire surface of the passivation film 119 including the red, green, and blue color filters 121r, 125g, and 127b. At this time, as the material for forming the overcoat layer 131, organic materials including photo-acryl and polyimide may be selected and used.

Then, a halftone mask 160 is disposed on the overcoat layer 131 so as to face the overcoat layer. At this time, the halftone mask 160 includes the light interception portion 161, the transmissive portion 163, and the transflective portion 165.

Referring to FIG. 9J, the overcoat layer 131 is photo-processed through the halftone mask 160, and then the overcoat layer 131 is patterned through a development process. At this time, the portion of the overcoat layer 131 which is not exposed by the light shielding portion 161 of the halftone mask 160 remains, the portion of the overcoat layer 131 exposed through the transmissive portion 163 is completely removed, The portion of the overcoat layer 131 exposed through the transmissive portion 165 is removed by a part of the thickness.

Referring to FIG. 9K, the exposed contact hole 132 is formed by wet etching the exposed portion of the passivation film 119 with the overcoat layer 131 removed by a certain thickness using the etching mask. At this time, the drain contact hole 132 is located in the thin film transistor portion T in the red (R), green (G) and blue sub pixel regions 151, 155 and 157 as well as the white sub pixel region 153 The overcoat layer 131 and the passivation film 119 can be formed.

Referring to FIG. 9L, the overcoat layer 131 is subjected to an ashing process to remove a part of the thickness of the overcoat layer 131. Since the red, green, and blue color filters 121r, 125g, and 127b are within the openings 115r, 115g, and 115b, even if the overcoat layer 131 is partially removed by the ashing process, , The overcoat layer 131 on the blue color filters 121r, 125g, and 127b is not lost.

9M, a third metal material layer (not shown) is deposited on the overcoat layer 131 and then a third metal material layer (not shown) is selectively patterned through a photolithographic process technique The drain electrode 117c of the thin film transistor through the drain contact hole 132 and the anode electrode 133 having the shape separated from each pixel region P are formed. At this time, the third metal material layer (not shown) may be made of aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum (MoTi), chromium (Ti) may be used.

Although not shown in the drawing, a plurality of pixel electrodes (not shown) may be formed on the anode electrode 133 at the boundaries of the pixel regions P and non-display regions (not shown), such as benzocyclobutene (BCB), polyimide Thereby forming an insulating material layer (not shown) made of photo acryl. At this time, the insulating material layer (not shown) defines the OLED light emitting region, that is, each sub pixel region, and insulates each of the sub pixel regions. In addition to the organic material such as polyimide (PI), an inorganic material may be applied to the insulating material layer (not shown).

9N, an insulating material layer (not shown) is selectively patterned to form the banks 135. [ At this time, the bank 135 is formed so as to overlap the rim of the anode electrode 133 in the form of surrounding each of the sub-pixel regions 151, 153, 155 and 157, and a plurality of openings As shown in Fig.

9O, an organic light emitting layer 137 is formed on the entire surfaces of the anode electrode 133 and the banks 135 in the respective sub-pixel regions 151, 153, 155 and 157 surrounded by the banks 135. In this case, the organic light emitting layer 137 may be formed of a single layer made of an organic light emitting material. Alternatively, a hole injection layer, a hole transporting layer, a light emitting material, A light emitting layer, an emitting material layer, an electron transporting layer, and an electron injection layer.

Then, referring to FIG. 9P, a cathode electrode 139 is formed on the entire surface of the organic light emitting layer 137. At this time, the cathode electrode 139 may use at least one selected from a transparent conductive material that transmits light, for example, a conductive material including ITO and IZO.

The cathode electrode 139 may be a transparent electrode or a reflective electrode. When used as a transparent electrode, a metal having a low work function, that is, Li, Ca, LiF / Ca, LiF / Al, And these compounds are oriented so as to face the organic light emitting layer 129, and an auxiliary electrode layer or a bus electrode line may be formed thereon with a transparent electrode forming material such as ITO, IZO, ZnO, or In ₂ O ₃ have. Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, or a compound thereof when the electrode is used as a reflective electrode.

The organic light emitting layer 135 between the anode electrode 133 and the cathode electrode 139 and between the two electrodes 133 and 139 forms the organic light emitting diode E.

The anode electrode 133 is electrically connected to the drain electrode 117b of the thin film transistor TFT by an electric field. The organic electroluminescent device E emits red, green, And the cathode electrode 139 is provided so as to cover all the pixels to supply a minus (-) power.

The anode electrode 133 and the cathode electrode 139 are insulated from each other by the organic light emitting layer 137 and a voltage having a different polarity is applied to the organic light emitting layer 137 to cause the organic light emitting layer 137 to emit light do.

Therefore, when a predetermined voltage is applied to the anode electrode 133 and the cathode electrode 139 according to the selected color signal, the organic light emitting diode E having such a structure is turned on, and the holes injected from the anode electrode 133 and the cathode Electrons provided from the electrode 139 are transported to the organic light emitting layer 137 to form an exciton. When the exciton transitions from the excited state to the ground state, light is emitted and emitted as visible light. At this time, the emitted light passes through the transparent cathode electrode 139 and exits to the outside.

As described above, according to the present invention, by designing the opening for inserting the color filter in the interlayer insulating films of the red, green, and blue pixel regions except for the white pixel region, the step (i.e., height) It is possible to increase the thickness margin of the remaining overcoat layer.

In particular, the present invention can mitigate the difference in overcoat layer thickness by red, white, blue, and green pixels after the photolithography of the overcoat layer, thereby increasing the thickness margin of the remaining overcoat layer.

In addition, the present invention can form openings for inserting red, green, and blue color filters in the interlayer insulating films of the red, green, and blue sub-pixel regions except the white sub-pixel region without additional masking process. Can be simplified.

Moreover, the present invention prevents the overcoat layer on the red, green, and blue color filters from being lost, as the red, green, and blue color filters are within the openings, even if some thickness of the overcoat layer is removed by the ashing process.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. , Separation, substitution, and alteration of the invention will be apparent to those skilled in the art. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: organic light emitting display device 110: display panel
109: interlayer insulating film 115r, 115g, 115b:
121r: Red color filter 125g: Green color filter
127b: blue color filter 131: overcoat layer
133: anode electrode 135: bank
137: organic light emitting layer 139: cathode electrode
151: Red sub-pixel area 153: White sub-pixel area
155: green subpixel region 157: blue subpixel region

Claims (8)

Red, white, green, and blue sub-pixel regions defined in a substrate and forming a pixel region;
A thin film transistor provided in a plurality of sub-pixel regions of the substrate;
An interlayer insulating layer provided on the entire surface of the substrate including the thin film transistor and having openings at positions corresponding to the remaining sub pixel regions excluding the white sub pixel region among the plurality of sub pixel regions;
Red, green, and blue color filters provided in respective openings located in the red, green, and blue sub-pixel regions;
An overcoat layer provided on the entire surface of the substrate including the red, green, and blue color filters to expose drain electrodes of the thin film transistors provided in the plurality of sub pixel regions;
An anode electrode connected to the drain electrode and provided in the sub-pixel regions;
A bank provided on the edge portion of the anode electrode and on the overcoat layer;
An organic light emitting layer provided on the anode electrode; And
And a cathode electrode provided on a front surface of the substrate including the organic light emitting layer. The OLED display according to claim 1, wherein the openings are provided in the interlayer insulating film in the red, green, and blue sub-pixel regions. The OLED display of claim 1, further comprising a passivation film between the red, green, and blue color filters and the openings. The OLED display according to claim 1, wherein the step of the red, green, and blue color filters is as small as the thickness of the interlayer insulating film. Defining red, white, green, and blue sub-pixel regions constituting a pixel region on a substrate;
Forming thin film transistors in a plurality of sub-pixel regions of the substrate;
Forming an interlayer insulating film on the entire surface of the substrate including the thin film transistor;
Forming openings in the interlayer insulating film at positions corresponding to the remaining sub-pixel regions excluding the white sub-pixel region among the plurality of sub-pixel regions;
Forming red, green, and blue color filters in each of the openings located in the red, green, and blue sub-pixel regions;
Forming an overcoat layer over the entire surface of the substrate including the red, green, and blue color filters;
Forming a drain contact hole exposing a drain electrode of a thin film transistor provided in a plurality of sub pixel regions in the overcoat layer;
Forming an anode electrode in the sub-pixel regions on the overcoat layer and connected to the drain electrode through the drain contact hole;
Forming a bank on the edge portion of the anode electrode and on the overcoat layer;
Forming an organic light emitting layer on the anode electrode; And
And forming a cathode electrode on the entire surface of the substrate including the organic light emitting layer. 6. The method of claim 5, wherein the openings are formed in the interlayer insulating film in the red, green, and blue sub-pixel regions. 6. The method of claim 5, further comprising forming a passivation film between the red, green, and blue color filters and the openings. 8. The method of claim 7, wherein forming the drain contact hole comprises:
Exposing the overcoat layer using a halftone mask,
Etching the passivation film under the exposed overcoat layer to form a drain contact hole;
And a step of ashing the exposed overcoat layer.

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