CN110660839A

CN110660839A - Display panel and preparation method thereof

Info

Publication number: CN110660839A
Application number: CN201911106229.2A
Authority: CN
Inventors: 宋威; 赵策; 王明; 刘宁; 李伟; 李广耀; 胡迎宾; 倪柳松
Original assignee: BOE Technology Group Co Ltd; Hefei Xinsheng Optoelectronics Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Hefei Xinsheng Optoelectronics Technology Co Ltd
Priority date: 2019-11-13
Filing date: 2019-11-13
Publication date: 2020-01-07
Anticipated expiration: 2039-11-13
Also published as: CN110660839B

Abstract

The invention provides a display panel and a preparation method thereof, which can ensure that photoresist is coated on the surface of the whole insulating film more uniformly. The method avoids the situation that after the photoresist is patterned, when the insulating film which is not covered by the photoresist is etched to form the first via hole insulating layer, the rest positions which are not required to be etched are etched, so that the display quality of the display panel is ensured. The driving back plate includes: the pixel driving circuit comprises a substrate, a pixel driving circuit and an insulating layer, wherein the pixel driving circuit is arranged on the substrate and positioned in each sub-pixel; the insulating layer comprises a first via hole which is used for connecting the pixel driving circuit; the insulating layer comprises a flat layer and an adhesion layer, and the adhesion layer is arranged on one side of the flat layer, which is far away from the substrate; the material of the flat layer is organic material, and the material of the adhesion layer is inorganic insulating material.

Description

Display panel and preparation method thereof

Technical Field

The invention relates to the technical field of display, in particular to a display panel and a preparation method thereof.

Background

A self-Light Emitting display device such as an Organic Light Emitting Diode (OLED) display panel has the advantages of self-Light Emitting, lightness and thinness, low power consumption, good color rendition, sensitive response, wide viewing angle, etc., and has been widely applied to display devices such as mobile phones, notebook computers, televisions, etc., and becomes the mainstream of the current market.

Disclosure of Invention

Embodiments of the present invention provide a display panel and a method for manufacturing the same, which can make the surface of the entire insulating film of a photoresist coated more uniformly when the photoresist is coated after the insulating film is manufactured. The method avoids the situation that after the photoresist is patterned, when the insulating film uncovered by the photoresist is etched to form the first through hole, the rest positions which are not required to be etched are etched, so that the display quality of the display panel is ensured.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

in one aspect, there is provided a display panel including: the pixel driving circuit comprises a substrate, a pixel driving circuit and a light emitting device which are arranged on the substrate and located in each sub-pixel, and an insulating layer arranged on one side, far away from the substrate, of the pixel driving circuit.

In each sub-pixel, the first electrode is electrically connected with the pixel driving circuit through the first via hole, and the first via hole penetrates through the insulating layer.

The light-emitting device comprises a first electrode and a second electrode positioned on one side of the first electrode, which is far away from the substrate.

The insulating layer comprises a flat layer and an adhesive layer, and the adhesive layer is arranged on one side of the flat layer, which is far away from the substrate; the material of the flat layer is organic material, and the material of the adhesion layer is inorganic insulating material.

Optionally, the adhesion layer is a single layer structure or a multilayer laminated structure.

Optionally, the material of the adhesion layer is selected from at least one of SiO, SiON, and SiN.

Optionally, the insulating layer further includes a passivation layer disposed on a side of the planarization layer close to the substrate.

The passivation layer is made of an inorganic insulating material.

Optionally, the light emitting device is a top emission type light emitting device; the light-emitting device comprises a first electrode and a second electrode positioned on one side of the first electrode, which is far away from the substrate.

In each sub-pixel, the first electrode is electrically connected to the pixel driving circuit through the first via.

Optionally, the pixel driving circuit includes a plurality of transistors, and the transistors include a source and a drain.

The driving backplane further comprises a pixel defining layer and an auxiliary cathode; the pixel defining layer is used for defining the position of the light emitting device; the auxiliary cathode and the source electrode and the drain electrode are made of the same material at the same layer, and the auxiliary cathode and the second electrode are electrically connected through a second via hole and a third via hole which are arranged on the insulating layer.

The second via hole penetrates through the insulating layer, the third via hole penetrates through the pixel defining layer, and the second via hole and the third via hole are arranged in a stacked mode.

In another aspect, an embodiment of the present invention provides a display device, including the display panel.

In another aspect, a method for manufacturing a display panel is provided, including:

forming an insulating film over a substrate over which a pixel driver circuit is formed; the pixel driving circuit is positioned in each sub-pixel area; the insulating film comprises a flat film and an adhesive film positioned on one side, far away from the substrate, of the flat film, the flat film is made of an organic material, and the adhesive film is made of an inorganic insulating material.

And forming a photoresist film on the adhesive film, and patterning to form a photoresist pattern.

Etching the insulating film exposed by the photoresist pattern to form an insulating layer comprising a first via hole; the first via hole is used for connecting the pixel driving circuit.

Forming a top emission type light emitting device in each sub-pixel; the light-emitting device comprises a first electrode, a second electrode and a light-emitting layer, wherein the second electrode is positioned on one side, far away from the substrate, of the first electrode, and the light-emitting layer is positioned between the first electrode and the second electrode; in each sub-pixel, the first electrode is electrically connected to the pixel driving circuit through the first via.

Etching the insulating film exposed by the photoresist to form an insulating layer including a first via hole, including: and etching the insulating film exposed out of the photoresist by using a dry etching process to form an insulating layer comprising a first via hole.

Optionally, the preparation method of the display panel further includes:

optionally, the light emitting layer is formed by an inkjet printing process.

Embodiments of the present invention provide a display panel, in which an insulating layer includes a flat layer and an adhesion layer, the adhesion layer is disposed on a side of the flat layer away from a substrate, and a material of the adhesion layer is an inorganic insulating material, so that an adhesion force between the inorganic insulating material and a photoresist is greater than that of an organic material, thereby making a surface of an entire insulating film of the photoresist coated more uniformly. The method avoids the situation that after the photoresist is patterned, when the insulating film uncovered by the photoresist is etched to form the first through hole, the rest positions which are not required to be etched are etched, so that the display quality of the display panel is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a display panel according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a sub-pixel P according to an embodiment of the present invention;

fig. 3 is a schematic partial structure diagram of a display panel according to an embodiment of the present invention;

fig. 4 is a schematic partial structure diagram of another display panel according to an embodiment of the present invention;

fig. 5 is a schematic partial structure diagram of another display panel according to an embodiment of the present invention;

fig. 6 is a schematic partial structure diagram of another display panel according to an embodiment of the present invention;

fig. 7 is a schematic partial structure diagram of another display panel according to an embodiment of the present invention;

fig. 8 is a schematic partial structure diagram of another display panel according to an embodiment of the present invention;

fig. 9 is a schematic flowchart of a method for manufacturing a display panel according to an embodiment of the invention;

fig. 10 is a schematic view of a manufacturing process of a method for manufacturing a display panel according to an embodiment of the present invention.

Reference numerals:

t1 — first transistor; 10-a substrate; 11-an insulating layer; 20-an interlayer insulating layer; 30-an auxiliary cathode; 40-a first metal pattern; 50-a buffer layer; 60-a pixel defining layer; 70-an insulating film; 80-a photoresist film; 90-photoresist pattern; 110 — a first via; 111-a planar layer; 112-an adhesion layer; 113-a passivation layer; 120-top emitting OLED devices; 121-a first electrode; 122-a second electrode; 123-a light emitting layer; 13-a source electrode; 134-drain electrode; 301-a second via; 401-a fourth via; 601-a third via; 701-flat film; 702-an adhesive film; 1321-a first channel region; 1322-first source region; 1323-first drain region.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

With the development of display technology, the resolution of display panels is gradually increasing. Taking a high-definition self-luminous display panel (e.g., a 55-inch 8K display panel) as an example, the light emitting device is a top-emission type light emitting device, and the light emitting material in the light emitting device can be prepared by using inkjet printing or vacuum evaporation technology.

The vacuum evaporation technology has the defects of low material utilization rate, suitability for small-molecule luminescent materials and inapplicability to large-size products. The ink jet printing technology is not limited by materials, and can be a macromolecular luminescent material or a small molecular luminescent material, and because the luminescent material solution is directly dripped into a specified area and flows to form a luminescent layer in the area, the utilization rate of the materials is high.

The self-luminous display panel is provided with the pixel driving circuit and the light emitting device in each sub-pixel area, the pixel driving circuit is located in the area where the light emitting device is manufactured for the top-luminous display panel, after the pixel driving circuit is manufactured, the section difference formed by the area where the metal wiring is arranged and the area where the metal wiring is not arranged exists in the area where the light emitting device is manufactured, the thickness of the light emitting layer printed by ink jet is not uniform due to the section difference, and therefore light emitting is not uniform and the display effect is affected.

In order to avoid this, the level difference may be smoothed by forming a planarization layer before the light emitting device is formed. After the preparation of the flat layer is finished, a Photo Resist (PR) is coated on the flat layer, the flat layer is patterned through the processes of exposure, development, etching and the like, then a via hole is formed by etching the flat layer which is not covered by the PR, and a pixel driving circuit in the display panel is electrically connected with the light-emitting device through the via hole.

However, the material of the planarization layer is an organic material, the surface of the planarization layer has many hydrophilic groups and insufficient adhesion force with the PR glue, and when the PR glue is coated after the planarization layer is manufactured, the edge of the planarization layer is easily coated unevenly, so that the planarization layer uncovered by the PR glue does not only include the region where the via hole needs to be manufactured, and thus when the planarization layer uncovered by the PR glue is etched, the portion of the planarization layer which is not to be removed is etched, and the display quality of the display panel is affected.

Accordingly, as shown in fig. 1, an embodiment of the invention provides a display panel, which includes a display area (AA area for short) and a peripheral area S, for example, the peripheral area S is disposed around the AA area by one turn. The AA area includes sub-pixels P of a plurality of colors. The multi-color sub-pixels P include at least a first color sub-pixel, a second color sub-pixel, and a third color sub-pixel, the first color, the second color, and the third color being three primary colors (e.g., red, green, and blue).

Fig. 1 illustrates an example in which the plurality of sub-pixels P are arranged in a matrix. In this case, the subpixels P arranged in one row in the horizontal direction X may be referred to as the same row of subpixels, and the same row of subpixels may be connected to one gate line. The subpixels P arranged in one row in the vertical direction Y may be referred to as the same column of subpixels, and the same column of subpixels may be connected to one data line.

The display panel is provided with a pixel driving circuit of the same structure and a light emitting device in each sub-pixel.

That is, as shown in fig. 2, in each sub-pixel P of the display panel, a pixel driving circuit and a light emitting device 120 are included. The light emitting device 120 includes first and

second electrodes

121 and 122, and a light emitting layer 123 between the first and

second electrodes

121 and 122. In each subpixel, the first electrode 121 is electrically connected to a pixel driving circuit through a via hole. Here, a specific structure of the pixel driving circuit is not illustrated in fig. 2, and the structure of the pixel driving circuit is not limited in the embodiment of the present invention.

Alternatively, the first electrode 121 is an anode, and the second electrode 122 is a cathode.

The light emitting layer 123 may include, for example, a light emitting layer, a hole transport layer between the light emitting layer and the first electrode 121, and an electron transport layer between the light emitting layer and the second electrode 122. Of course, in some embodiments, a hole injection layer may be disposed between the hole transport layer and the first electrode 121, and an electron injection layer may be disposed between the electron transport layer and the second electrode 122, as desired.

On the basis of the above, the light emitting device 120 is optionally a top emission type light emitting device. For example, the material of the second electrode 122 may be silver (Ag), and the material of the first electrode 121 may be Indium Tin Oxide (ITO). The second electrode 122 is thin and semitransparent.

As shown in fig. 3, the embodiment of the invention provides a display panel, which includes a substrate 10, a pixel driving circuit and a light emitting device disposed on the substrate 10 and in each sub-pixel P, and an insulating layer 11 disposed on a side of the pixel driving circuit away from the substrate 10.

The light emitting device 120 includes a first electrode 121 and a second electrode 122 positioned on a side of the first electrode 121 remote from the substrate 10.

In each sub-pixel, the first electrode 121 is electrically connected to the pixel driving circuit through a first via 113, and the first via 113 penetrates the insulating layer 11.

The insulating layer 11 comprises a flat layer 111 and an adhesion layer 112, wherein the adhesion layer 112 is arranged on one side of the flat layer 111 far away from the substrate 10; the material of the planarization layer 111 is an organic material, and the material of the adhesion layer 112 is an inorganic insulating material.

Alternatively, the material of the planarization layer 111 may be Organic Siloxane (SOG).

Optionally, the thickness of the adhesion layer 112 ranges from

For example, the adhesion layer 112 can be formed by Plasma Enhanced Chemical Vapor Deposition (PECVD) or Physical Vapor Deposition (PVD).

Note that the pixel driving circuit includes a plurality of transistors, and fig. 3 shows only the first transistor T1 connected to the light emitting device, and the first transistor T1 may be a driving transistor, for example, or may be a transistor functioning as a switch. When the pixel driving circuit has a 2T1C or 3T1C structure, the first transistor T1 is a driving transistor.

Wherein the first transistor T1 includes a gate electrode 131, a semiconductor active pattern 132, a source electrode 133, and a drain electrode 134. The semiconductor active pattern 132 includes a channel region 1321, a source region 1322, and a drain region 1323. The first electrode 121 may be electrically connected to the drain electrode 134 through the first via 110.

Wherein the source region 1322 and the drain region 1323 have a conductivity greater than that of the channel region 1321, the source 133 contacts a portion of the semiconductor active pattern 132 corresponding to the source region 1322, and the drain 134 contacts a portion of the semiconductor active pattern 132 corresponding to the drain region 1323.

For example, the portion of the semiconductor active pattern 132 corresponding to the source region 1322 and the drain region 1323 may be subjected to a conductor formation by ion implantation, and the ions may be boron ions or phosphorus ions.

For example, the gate insulating pattern 135 may have a single layer structure or a multi-layer laminated structure, and the material thereof may be silicon nitride (SiNx) and silicon oxide (SiO)₂) And the like. The material of the first semiconductor active pattern 132 may be selected from semiconductor oxides, such as indium zinc oxide (IGZO).

For example, the gate, source, and drain of each transistor in the pixel driving circuit may be made of a material selected from elemental metals of copper (Cu), aluminum (Al), molybdenum (Mo), titanium (Ti), chromium (Cr), and tungsten (W), and a metal alloy made of the elemental metals.

In fig. 3, the first transistor T1 is illustrated as a top gate transistor, in which case the semiconductor active pattern 132 is disposed on the side of the gate 131 close to the substrate 10, the semiconductor active pattern 132 is isolated from the gate 131 by the gate insulating pattern 135, and the source 133 and the drain 134 are isolated from the gate 131 by the interlayer insulating layer 20. Wherein the semiconductor active pattern 135 and the gate electrode 131 may be simultaneously formed, and based on this, the source and drain

electrodes

133 and 134 are in contact with the semiconductor active pattern 132 through a via hole penetrating the interlayer insulating layer 20.

It is understood by those skilled in the art that the source and drain

electrodes

133 and 134 are in contact with the semiconductor active pattern 132 through vias penetrating the interlayer insulating layer 20 and the gate insulating layer in the case where the gate insulating layer is not patterned.

The embodiment of the invention provides a display panel, wherein the insulation layer 11 comprises a flat layer 111 and an adhesion layer 112, the adhesion layer 112 is arranged on one side of the flat layer 111 far away from the substrate 10, and the adhesion layer 112 is made of an inorganic insulation material, so that the adhesion between the inorganic insulation material and the PR glue is larger compared with an organic material, and the PR glue is coated on the surface of the whole insulation film more uniformly. The method avoids the etching of other positions which are not required to be etched when the insulating film which is not covered by the PR glue is etched to form the insulating layer 11 comprising the first via hole 110 after the PR glue is patterned, so as to ensure the display quality of the display panel.

Alternatively, the adhesive layer 112 is a single-layer structure or a multi-layer laminated structure.

The multilayer laminated structure enables the upper surface of the adhesive layer 112 to be more flat than the adhesive layer 112 having a single-layer structure.

Optionally, the material of the adhesion layer 112 is selected from at least one of silicon monoxide SiO, silicon oxynitride SiON, and silicon nitride SiN.

Optionally, as shown in fig. 4, the insulating layer 11 further includes a passivation layer 113 disposed on a side of the planarization layer 111 close to the substrate 10. The material of the passivation layer 113 is an inorganic insulating material.

Optionally, the material of the passivation layer 113 is selected from SiO₂At least one of SiON and SiN.

The passivation layer 113 can prevent impurities such as water and oxygen from being introduced into the pixel driving circuit in the process of manufacturing the adhesion layer 112, so that the performance of the pixel driving circuit is affected, and the quality of the whole driving back plate is affected.

Alternatively, the light emitting device 120 is a top emission type light emitting device.

Optionally, as shown in fig. 5 and fig. 6, the display panel further includes an auxiliary cathode 30, and the auxiliary cathode 30 and the source and drain of each transistor in the pixel driving circuit are made of the same material. On this basis, the display panel further includes a pixel defining layer 60, the pixel defining layer 60 is used for defining the position of the light emitting device 120, the auxiliary cathode 30 and the second electrode 122 are electrically connected through a second via 301 and a third via 601, the second via 301 penetrates through the insulating layer, the third via 601 penetrates through the pixel defining layer 60, and the second via 301 and the third via 601 are stacked and communicated.

It will be appreciated that the transistors in the pixel drive circuit are formed simultaneously, i.e. the source and drain of the transistor functioning as a switch are of the same material as the source and drain of the drive transistor, and the gate of the transistor functioning as a switch is of the same material as the gate of the drive transistor.

Fig. 5 and 6 show only the first transistor T1 connected to the light emitting device 120, and accordingly, the auxiliary cathode 30 is formed of the same material as the source and drain

electrodes

133 and 134 of the first transistor T1.

By providing the auxiliary cathode 30 and electrically connecting the auxiliary cathode 30 and the second electrode 122, the resistance of the second electrode 122 can be reduced.

Optionally, as shown in fig. 7 and 8, the display panel further includes a metal pattern 40 and a buffer layer 50, where the buffer layer 50 is located on a side of the metal pattern 40 away from the substrate 10. Along the thickness direction of the substrate 10, the projection of the metal pattern 40 on the substrate 10 covers the projection of the semiconductor active pattern 132 of the driving transistor (exemplified by the first transistor T1 in fig. 7 and 8), and the metal pattern 40 is connected to the drain 134 of the driving transistor (i.e., the first transistor T1 in fig. 7 and 8).

Wherein the metal pattern 40 is electrically connected to the drain 134 of the first transistor T1 through the fourth via 401.

The metal pattern 40 may prevent light from being incident from the substrate 10 to the semiconductor active pattern of the driving transistor in the pixel driving circuit. Affecting the performance of the pixel drive circuit.

The embodiment of the invention provides a display device which comprises the display panel.

As shown in fig. 9, an embodiment of the present invention provides a method for manufacturing a display panel, including:

s10, as shown in fig. 10, forming an insulating film 70 on the substrate 10 on which the pixel drive circuit is formed; the pixel driving circuit is positioned in each sub-pixel area; the insulating film 70 includes a flat film 701 and an adhesive film 702 located on a side of the flat film 701 away from the substrate 10, the flat film 701 is made of an organic material, and the adhesive film 702 is made of an inorganic insulating material.

S20, as shown in fig. 10, a PR paste film 80 is formed on the adhesive film and patterned to form a PR paste pattern 90.

S30, as shown in fig. 10, etching the insulating film exposed by the PR paste pattern 90 to form an insulating layer 11 including a first via hole 110; the first via hole 110 is used to connect the pixel driving circuit.

S40, as shown in fig. 3, forming a top emission type light emitting device 120 in each sub-pixel; the light emitting device includes a first electrode 121, a second electrode 122 located on a side of the first electrode away from the substrate 10, and a light emitting layer 123 located between the first electrode 121 and the second electrode 122; in each subpixel, the first electrode 121 is electrically connected to the pixel driving circuit through the first via hole 110.

The embodiment of the invention provides a preparation method of a display panel, wherein before forming a PR glue 60 on an adhesive film, an insulating film is formed, so that the insulating film comprises a flat film and the adhesive film positioned on one side, far away from a substrate 10, of the flat film, the material of the flat film is an organic material, and the material of the adhesive film is an inorganic insulating material.

Etching the insulating film exposed by the photoresist to form the insulating layer 11 including the first via hole 110, including:

and etching the insulating film exposed by the PR glue by using a dry etching process to form the insulating layer 11 comprising the first via hole 110.

The insulating film comprises a flat film and an adhesive film positioned on one side of the flat film far away from the substrate 10, and when the materials of the flat film and the adhesive film both contain silicon (Si), the insulating film can be etched by utilizing a dry etching process, so that the manufacturing process is simplified.

Alternatively, the light emitting layer 123 is formed by an inkjet printing process.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A display panel, comprising: the pixel driving circuit comprises a substrate, a pixel driving circuit and a light emitting device which are arranged on the substrate and positioned in each sub-pixel, and an insulating layer arranged on one side, far away from the substrate, of the pixel driving circuit;

the light-emitting device comprises a first electrode and a second electrode positioned on one side of the first electrode, which is far away from the substrate;

in each sub-pixel, the first electrode is electrically connected with the pixel driving circuit through a first via hole, and the first via hole penetrates through the insulating layer;

2. The display panel according to claim 1, wherein the adhesive layer is a single-layer structure or a multilayer laminated structure.

3. The display panel according to claim 2, wherein the material of the adhesion layer is at least one selected from the group consisting of SiO, SiON, and SiN.

4. The display panel according to claim 1, wherein the insulating layer further comprises a passivation layer disposed on a side of the planarization layer adjacent to the substrate;

the passivation layer is made of an inorganic insulating material.

5. The display panel according to claim 1, wherein the light-emitting device is a top emission type light-emitting device.

6. The display panel according to claim 1, wherein the pixel driving circuit comprises a plurality of transistors including a source and a drain;

the display panel further comprises a pixel defining layer and an auxiliary cathode; the pixel defining layer is used for defining the position of the light emitting device; the auxiliary cathode, the source electrode and the drain electrode are made of the same material at the same layer, and the auxiliary cathode is electrically connected with the second electrode through a second through hole and a third through hole;

the second via hole penetrates through the insulating layer, the third via hole penetrates through the pixel defining layer, and the second via hole and the third via hole are stacked and communicated.

7. A display device comprising the display panel according to any one of claims 1 to 6.

8. A method for manufacturing a display panel, comprising:

forming an insulating film over a substrate over which a pixel driver circuit is formed; the pixel driving circuit is positioned in each sub-pixel area; the insulating film comprises a flat film and an adhesive film positioned on one side of the flat film, which is far away from the substrate, wherein the flat film is made of an organic material, and the adhesive film is made of an inorganic insulating material;

forming a photoresist film on the adhesive film, and patterning to form a photoresist pattern;

etching the insulating film exposed by the photoresist pattern to form an insulating layer comprising a first via hole; the first via hole is used for connecting the pixel driving circuit;

9. The method for manufacturing a display panel according to claim 8, wherein a material of the adhesion film is at least one selected from the group consisting of SiO, SiON, and SiN;

etching the insulating film exposed by the photoresist to form an insulating layer including a first via hole, including:

and etching the insulating film exposed out of the photoresist by using a dry etching process to form an insulating layer comprising a first via hole.

10. The method for manufacturing a display panel according to claim 8, wherein the light-emitting layer is formed by an inkjet printing process.