阅读说明：本技术 一种显示基板及其制备方法、显示装置 (Display substrate, preparation method thereof and display device ) 是由 梁永民 简月圆 于 2019-09-19 设计创作，主要内容包括：本发明公开了一种显示基板及其制备方法、显示装置。显示基板的制备方法包括：在基底上形成控制结构层；在控制结构层上形成第一平坦层；在第一平坦层上形成支撑结构,支撑结构的材质包括负性光敏聚合物；在形成支撑结构的第一平坦层上形成包覆支撑结构的保护层；在保护层上形成第二平坦层；在第二平坦层上形成第一电极,第一电极穿过第二平坦层、保护层和第一平坦层与控制结构层电连接。该方法,形成了包覆支撑结构的保护层,杜绝了水汽通过支撑结构侵入,有效隔绝了水汽,避免了后续形成的发光层被腐蚀的问题,另外,第一电极在保护层之后形成,从而形成保护层的过程不会对第一电极产生影响,保证了显示基板的显示性能。(The invention discloses a display substrate, a preparation method thereof and a display device. The preparation method of the display substrate comprises the following steps: forming a control structure layer on a substrate; forming a first flat layer on the control structure layer; forming a support structure on the first flat layer, wherein the material of the support structure comprises negative photosensitive polymer; forming a protective layer for coating the support structure on the first flat layer for forming the support structure; forming a second planarization layer on the protection layer; and forming a first electrode on the second flat layer, wherein the first electrode penetrates through the second flat layer, the protective layer and the first flat layer to be electrically connected with the control structure layer. In addition, the first electrode is formed after the protective layer, so that the process of forming the protective layer cannot influence the first electrode, and the display performance of the display substrate is ensured.)

1. A method for preparing a display substrate is characterized by comprising the following steps:

forming a control structure layer on a substrate;

forming a first flat layer on the control structure layer;

forming a support structure on the first flat layer, wherein the material of the support structure comprises a negative photosensitive polymer;

forming a protective layer covering the support structure on the first flat layer forming the support structure;

forming a second planarization layer on the protective layer;

and forming a first electrode on the second flat layer, wherein the first electrode passes through the second flat layer, the protective layer and the first flat layer and is electrically connected with the control structure layer.

2. The method of claim 1, wherein forming a control structure layer on a substrate comprises:

forming an active layer and a gate electrode on a substrate;

and forming a source electrode and a drain electrode on the substrate on which the active layer and the gate electrode are formed, wherein the source electrode and the drain electrode are respectively electrically connected with the active layer.

3. The method of claim 1, wherein forming a second planar layer on the protective layer comprises:

forming an intermediate metal layer on the protective layer, wherein the intermediate metal layer penetrates through the protective layer and the first flat layer to be electrically connected with the control structure layer;

and forming a second flat layer on the substrate on which the intermediate metal layer is formed, wherein a fourth through hole exposing the intermediate metal layer is formed on the second flat layer, and the first electrode is electrically connected with the intermediate metal layer through the fourth through hole.

4. The method of claim 1, wherein the material of the first planarization layer comprises a positive polyimide.

5. The method of claim 1, further comprising:

forming a pixel defining layer on the first electrode, wherein the pixel defining layer is provided with a sub-pixel opening for exposing the first electrode;

and forming a light emitting layer in the sub-pixel opening by an evaporation process.

6. A display substrate, comprising:

a substrate;

a control structure layer disposed on the substrate;

the first flat layer is arranged on the control structure layer;

the supporting structure is arranged on the first flat layer, and the material of the supporting structure comprises a negative photosensitive polymer;

the protective layer is arranged on the first flat layer on which the supporting structure is formed, and covers the supporting structure;

a second planarization layer disposed on the protective layer, and,

and the first electrode is arranged on the second flat layer, penetrates through the second flat layer, the protective layer and the first flat layer and is electrically connected with the control structure layer.

7. The display substrate of claim 6, wherein the cross-section of the support structure in the direction perpendicular to the base is an inverted trapezoid, and wherein a top edge of the support structure facing away from the base has a width greater than a bottom edge of the support structure facing toward the base.

8. The display substrate of claim 7, wherein an angle between a side surface of the support structure and a bottom surface of the support structure facing the base is 90 ° to 130 °.

9. The display substrate of claim 6, wherein the support structure has a dimension perpendicular to the base of 1.0 μm to 1.5 μm.

10. The display substrate according to any one of claims 6 to 9, wherein the protective layer has a thickness of 3000 to 5000 angstroms.

11. The display substrate according to any one of claims 6 to 9, wherein the material of the first planarization layer comprises positive polyimide.

12. The display substrate of any one of claims 6 to 9, further comprising an intermediate metal layer disposed between the protective layer and the second planar layer, wherein the intermediate metal layer is electrically connected to the control structure layer through the protective layer and the first planar layer, and wherein the first electrode is electrically connected to the intermediate metal layer through the second planar layer.

13. The display substrate according to any one of claims 6 to 9, further comprising a pixel defining layer disposed on the first electrode, wherein the pixel defining layer is provided with a sub-pixel opening exposing the first electrode, and a light emitting layer is disposed in the sub-pixel opening.

14. A display substrate according to any one of claims 6 to 9, wherein the display substrate comprises a plurality of pixel units, each pixel unit comprises a plurality of sub-pixels, and the support structure is arranged between two adjacent pixel units.

15. A display device comprising the display substrate according to any one of claims 6 to 14.

Technical Field

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

Background

In an Organic Light-Emitting Diode (OLED) evaporation process, in order to keep a certain distance between a mask plate and a substrate, a support structure is generally required to be disposed on the substrate to be evaporated to keep the distance between the mask plate and the substrate.

Two materials that are often used to fabricate support structures include positive photoresists (e.g., positive photoresists) which are high molecular weight polymers and negative photoresists which are small molecular components, and negative photoresists (e.g., negative photoresists). Compared with the supporting structure made of the positive photoresist, the supporting structure made of the negative photoresist has better supporting effect on the mask plate. However, the negative photoresist is a small molecular component, the compactness of the negative photoresist is not good as that of the positive photoresist, and the water absorption and air permeability of the negative photoresist are also high, so that when the negative photoresist is used for manufacturing a supporting structure, although the supporting effect is improved, the water vapor cannot be effectively isolated, the light-emitting layer is easy to corrode, and the service life of a light-emitting device is influenced.

Disclosure of Invention

An object of an embodiment of the present invention is to provide a display substrate, a method for manufacturing the same, and a display device, so as to prevent moisture from entering the interior of the display substrate through a supporting structure.

In order to solve the above technical problem, an embodiment of the present invention provides a method for manufacturing a display substrate, including:

forming a control structure layer on a substrate;

forming a first flat layer on the control structure layer;

forming a support structure on the first flat layer, wherein the material of the support structure comprises a negative photosensitive polymer;

forming a protective layer covering the support structure on the first flat layer forming the support structure;

forming a second planarization layer on the protective layer;

and forming a first electrode on the second flat layer, wherein the first electrode passes through the second flat layer, the protective layer and the first flat layer and is electrically connected with the control structure layer.

Optionally, the forming a control structure layer on the substrate includes:

forming an active layer and a gate electrode on a substrate;

and forming a source electrode and a drain electrode on the substrate on which the active layer and the gate electrode are formed, wherein the source electrode and the drain electrode are respectively electrically connected with the active layer.

Optionally, the forming a second planar layer on the protective layer includes:

forming an intermediate metal layer on the protective layer, wherein the intermediate metal layer penetrates through the protective layer and the first flat layer to be electrically connected with the control structure layer;

and forming a second flat layer on the substrate on which the intermediate metal layer is formed, wherein a fourth through hole exposing the intermediate metal layer is formed on the second flat layer, and the first electrode is electrically connected with the intermediate metal layer through the fourth through hole.

Optionally, a material of the first planarization layer includes positive polyimide.

Optionally, the method further comprises:

forming a pixel defining layer on the first electrode, wherein the pixel defining layer is provided with a sub-pixel opening for exposing the first electrode;

and forming a light emitting layer in the sub-pixel opening by an evaporation process.

In order to solve the above technical problem, an embodiment of the present invention further provides a display substrate, including:

a substrate;

a control structure layer disposed on the substrate;

the first flat layer is arranged on the control structure layer;

the supporting structure is arranged on the first flat layer, and the material of the supporting structure comprises negative photosensitive polymer;

the protective layer is arranged on the first flat layer on which the supporting structure is formed, and covers the supporting structure;

a second planarization layer disposed on the protective layer, and,

and the first electrode is arranged on the second flat layer, penetrates through the second flat layer, the protective layer and the first flat layer and is electrically connected with the control structure layer.

Optionally, the cross section of the support structure in the direction perpendicular to the substrate is an inverted trapezoid, and the width of the top edge of the support structure on the side facing away from the substrate is greater than the width of the bottom edge of the support structure on the side facing toward the substrate.

Optionally, an angle between a side of the support structure and a bottom surface of the support structure facing the substrate side is 90 ° to 130 °.

Optionally, the support structure has a dimension in a direction perpendicular to the base of 1.0 μm to 1.5 μm.

Optionally, the protective layer has a thickness of 3000 angstroms to 5000 angstroms.

Optionally, a material of the first planarization layer includes positive polyimide.

Optionally, the display substrate further includes an intermediate metal layer disposed between the protective layer and the second flat layer, the intermediate metal layer is electrically connected to the control structure layer through the protective layer and the first flat layer, and the first electrode is electrically connected to the intermediate metal layer through the second flat layer.

Optionally, the display substrate further includes a pixel defining layer disposed on the first electrode, the pixel defining layer is provided with a sub-pixel opening exposing the first electrode, and the sub-pixel opening is provided with a light emitting layer therein.

Optionally, the display substrate includes a plurality of pixel units, each pixel unit includes a plurality of sub-pixels, and the support structure is disposed between two adjacent pixel units.

In order to solve the above technical problem, an embodiment of the present invention further provides a display device, including the display substrate described above.

According to the preparation method of the display substrate, the protective layer for coating the support structure is formed on the support structure, water vapor can be prevented from entering the support structure through the protective layer, the water vapor is effectively isolated, and the problem that the subsequently formed light-emitting layer is corroded is solved. In addition, compared with the display substrate shown in fig. 3, in the preparation method of the display substrate according to the embodiment of the invention, the process for forming the first electrode is after the process for forming the protective layer, so that the influence of the process for forming the protective layer on the first electrode can be avoided, and the display performance of the display substrate is ensured. Moreover, the supporting structures are formed on the first flat layer, so that the fact that the supporting structures are formed on the same flat surface is guaranteed, the flatness of the top surfaces of the supporting structures is further guaranteed, gaps between the mask plate and the substrate in the evaporation process are guaranteed, and the evaporation effect is improved.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention and not to limit the invention.

FIGS. 1a to 1d are schematic views illustrating a process for manufacturing a display substrate;

FIG. 2 is a schematic view of another embodiment of a display substrate;

FIG. 3 is a schematic view of a display substrate according to an embodiment;

FIG. 4 is a schematic structural diagram illustrating a first planarization layer formed according to a first embodiment of the present invention;

FIG. 5 is a schematic structural view of a first embodiment of the present invention after forming a support structure;

FIG. 6 is a schematic structural diagram illustrating a first embodiment of the present invention after forming a passivation layer;

FIG. 7 is a schematic structural diagram illustrating a second planarization layer formed according to the first embodiment of the present invention;

FIG. 8 is a schematic structural diagram illustrating a first electrode formed according to the first embodiment of the present invention;

fig. 9 is a schematic structural view after a light-emitting layer is formed in the first embodiment of the present invention.

Description of reference numerals:

10-a glass substrate; 11-a flexible substrate; 12-a buffer layer;

20-control the structural layer; 21-an active layer; 22 — a first insulating layer;

23 — a first gate electrode; 24-a second insulating layer; 25 — a second gate electrode;

26 — a third insulating layer; 271-source electrode; 272-drain electrode;

31-a passivation layer; 32 — a first planarization layer; 321-sub via holes;

33 — intermediate metal layer; 34 — a second planarization layer; 341-fourth via;

35-a first electrode; 36-pixel definition layer; 37-a support structure;

38-a light emitting layer; 40, a protective layer; 401 — third via.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the present application, the embodiments and features of the embodiments may be arbitrarily combined with each other without conflict.

Fig. 1a to 1d are schematic views illustrating a manufacturing process of a display substrate, and referring to fig. 1a to 1d, the manufacturing process of the display substrate is as follows:

as shown in fig. 1a, a flexible substrate 11 is formed on a glass substrate 10; forming a buffer layer 12 on a flexible substrate 11; forming an active layer 21 on the buffer layer 12; forming a first insulating layer 22 on the active layer 21; forming a first gate electrode 23 on the first insulating layer 22; forming a second insulating layer 24 on the first gate electrode 23; a second gate electrode 25 is formed on the second insulating layer 24. The material of the flexible substrate 11 may be Polyimide (PI); the buffer layer 12, the first insulating layer 22 and the second insulating layer 24 may be made of silicon nitride SiNx, silicon oxide SiOx or a composite layer of SiNx/SiOx; the gate electrode can adopt one or more of metals such as platinum Pt, ruthenium Ru, gold Au, silver Ag, molybdenum Mo, chromium Cr, aluminum Al, tantalum Ta, titanium Ti, tungsten W and the like; the material of the active layer 21 may be polysilicon (p-Si).

As shown in fig. 1b, a third insulating layer 26 is formed on the glass substrate 10 on which the second gate electrode 25 is formed, and the third insulating layer 26 is opened with a first via hole and a second via hole exposing the active layer 21; a source electrode 271 and a drain electrode 272 are formed on the third insulating layer 26, and the source electrode 271 and the drain electrode 272 are electrically connected to the active layer 21 through a first via hole and a second via hole, respectively. The third insulating layer 26 may be made of silicon nitride SiNx, silicon oxide SiOx, or a composite layer of SiNx/SiOx.

As shown in fig. 1c, a passivation layer 31 and a first planarization layer 32 are sequentially formed on the glass substrate 10 on which the source electrode 271 and the drain electrode 272 are formed, and third via holes exposing the drain electrode 272 are opened on the passivation layer 31 and the first planarization layer 32; forming an intermediate metal layer 33 on the first planarization layer 32, the intermediate metal layer 33 being electrically connected to the drain electrode 272 through a third via hole; a second planarization layer 34 is formed on the middle metal layer 33, and a fourth via hole exposing the middle metal layer 33 is opened on the second planarization layer 34.

As shown in fig. 1d, a first electrode 35 is formed on the second planarization layer 34, the first electrode 35 is electrically connected to the intermediate metal layer 33 through a fourth via hole, the first electrode 35 is typically an anode of the OLED device, and the first electrode 35 is located in the sub-pixel region; forming a pixel defining layer 36 on the second planarization layer 34 formed with the first electrode 35, wherein the pixel defining layer 36 is formed with a sub-pixel opening exposing the first electrode 35 and a support opening exposing the second planarization layer 34; coating a photoresist film on the pixel defining layer 36, exposing and developing the photoresist film to form a supporting structure 37 at the position of the supporting opening, wherein the bottom surface of the supporting structure 37 is in contact with the second flat layer 34, and the top surface of the supporting structure 37 is higher than the top surface of the pixel defining layer 36; the light-emitting layer 38 located at the sub-pixel opening position is formed by an evaporation process. It is easily understood that in fig. 1a to 1d, only one sub-pixel is illustrated, and it is easily understood that one pixel unit may include three sub-pixels, for example, an R sub-pixel, a G sub-pixel, and a B sub-pixel, each having a corresponding thin film transistor.

In fig. 1d, the photoresist forming the support structure 37 is a positive photoresist. Positive photoresist is a high molecular polymer, and its portion irradiated with light can be decomposed into small molecules during exposure and removed by a developing process, and the blocked portion remains because it is not irradiated with light. In the positive photoresist exposure process, the shielding side part can generate diffracted light, and the diffracted light is absorbed after irradiating the photoresist material, so that the corresponding photoresist material is exposed, and the reserved part forms an acute-angle slope angle, so that the appearance of the formed support structure is similar to a regular trapezoid. Thus, in FIG. 1d, the cross-sectional profile of the support structure 37 is a regular trapezoid. When the light emitting layer 38 is formed by evaporation, the supporting structure 37 may be used to support the mask plate, so as to ensure the distance between the mask plate and the substrate with evaporation, and improve the evaporation effect.

Fig. 2 is a schematic structural diagram of a display substrate in another embodiment. In fig. 1d, the supporting structure 37 is in a regular trapezoid shape, the contact surface between the supporting structure 37 and the mask (the top surface of the supporting structure 37) is small, and the supporting effect is poor, and in order to improve the supporting effect of the supporting structure 37 on the mask, in another embodiment, different from fig. 1a to 1d, the photoresist forming the supporting structure is a negative photoresist, as shown in fig. 2. The negative photoresist is a small molecular component, and during the exposure process, the shielded part is developed and removed because of not being irradiated by light, and the energy of the light absorbed by the irradiated part is changed into high molecular polymer and is remained. In the negative photoresist exposure process, the shielding side part can generate diffracted light, and the diffracted light is absorbed after irradiating the photoresist material, so that the corresponding photoresist material is changed into a high molecular polymer, and the reserved part forms an obtuse-angle slope angle, so that the appearance of the formed support structure is similar to an inverted trapezoid. Thus, in fig. 2, the cross-sectional profile of the support structure 37 is formed as an inverted trapezoid. From the supporting effect, the contact area between the supporting structure and the mask plate is larger due to the inverted trapezoidal shape, so that the supporting effect is better. However, negative photoresists are small molecule components, are less dense than positive photoresists, and have high water absorption and gas permeability. Therefore, when the support structure is made of the negative photoresist, although the support effect is improved, the light-emitting layer is not effectively isolated from water vapor, so that the light-emitting layer is easily corroded, and the service life of the light-emitting device is influenced.

Fig. 3 is a schematic structural diagram of a display substrate according to an embodiment. In order to effectively isolate water vapor, the inventors propose a structure of a display substrate, as shown in fig. 3, compared with the display substrate shown in fig. 2, the display substrate shown in fig. 3 further includes a protective layer 40 covering the supporting structure 37. In order to secure the evaporation effect, the upper surface of the protective layer 40 in the region outside the support structure 37 cannot be higher than the upper surface of the pixel defining layer 36, and therefore, the protective layer 40 is formed on the first electrode 35. Therefore, the protective layer 40 is formed by forming the supporting structure 37 and the first electrode 35 on the second planarization layer 34, and then forming a protective film covering the supporting structure 37 and the first electrode 35, wherein the protective film may include silicon nitride SiNx or/and silicon oxide SiOx for moisture isolation; after exposure and development, the protective layer 40 is patterned by a dry etching process. In the process of forming the protective layer 40 by using the dry etching process, the first electrode 35 may be damaged by the dry etching process, and the display performance of the display substrate may be affected, so that the display basic structure shown in fig. 3 has certain display defects.

In order to solve the above technical problems, embodiments of the present invention provide a method for manufacturing a display substrate. The preparation method of the display substrate comprises the following steps: forming a control structure layer on a substrate; forming a first planarization layer on the control structure layer; forming a support structure on the first flat layer, wherein the material of the support structure comprises a negative photosensitive polymer; forming a protective layer for coating the support structure on the first flat layer for forming the support structure; forming a second planarization layer on the protective layer; and forming a first electrode on the second flat layer, wherein the first electrode passes through the second flat layer, the protective layer and the first flat layer and is electrically connected with the control structure layer.

According to the preparation method of the display substrate, the protective layer for coating the support structure is formed on the support structure, water vapor can be prevented from entering the support structure through the protective layer, the water vapor is effectively isolated, and the problem that the subsequently formed light-emitting layer is corroded is solved. In addition, compared with the display substrate shown in fig. 3, in the preparation method of the display substrate according to the embodiment of the invention, the process for forming the first electrode is after the process for forming the protective layer, so that the influence of the process for forming the protective layer on the first electrode can be avoided, and the display performance of the display substrate is ensured. Moreover, the supporting structures are formed on the first flat layer, so that the fact that the supporting structures are formed on the same flat surface is guaranteed, the flatness of the top surfaces of the supporting structures is further guaranteed, gaps between the mask plate and the substrate in the evaporation process are guaranteed, and the evaporation effect is improved.

The technical contents of the present invention will be described in detail by specific embodiments.

The first embodiment:

a first embodiment of the present invention provides a method for manufacturing a display substrate, including:

s1: forming a control structure layer 20 on a substrate 1;

s2: forming a first planarization layer 32 on the control structure layer 20;

s3: forming a support structure 37 on the first planarization layer 32, wherein the material of the support structure 37 includes a negative photosensitive polymer;

s4: forming a protective layer 40 covering the support structure 37 on the first planarization layer 32 forming the support structure 37;

s5: forming a second planarization layer 34 on the protection layer 40;

s6: a first electrode 35 is formed on the second planarization layer 34, and the first electrode 35 is electrically connected to the control structure layer 20 through the second planarization layer 34, the protective layer 40, and the first planarization layer 32.

According to the preparation method of the display substrate, the protective layer 40 for coating the support structure 37 is formed on the support structure 37, and the protective layer 40 can prevent water vapor from entering through the support structure 37, so that the water vapor is effectively isolated, and the problem that a subsequently formed light-emitting layer is corroded is solved. In addition, compared with the display substrate shown in fig. 3, in the preparation method of the display substrate according to the embodiment of the invention, the process for forming the first electrode 35 is performed after the process for forming the protective layer 40, so that the process for forming the protective layer 40 can be prevented from affecting the first electrode 35, and the display performance of the display substrate is ensured. Furthermore, the supporting structures 37 are formed on the first flat layer 32, so that the supporting structures 37 are guaranteed to be formed on the same flat surface, the flatness of the top surfaces of the supporting structures 37 is further guaranteed, the gap between the mask plate and the evaporation substrate in the evaporation process is guaranteed, and the evaporation effect is improved.

In one embodiment, the control structure layer 20 includes a thin film transistor formed on a substrate, and thus, forming the control structure layer on the substrate may include:

forming an active layer and a gate electrode on a substrate;

and forming a source electrode and a drain electrode on the substrate on which the active layer and the gate electrode are formed, wherein the source electrode and the drain electrode are respectively electrically connected with the active layer.

Thus, the first planarization layer 32 is formed on the source and drain electrodes. The protective layer 40 may be made of silicon nitride SiNx, silicon oxide SiOx, or a composite layer of SiNx/SiOx. Compared with the preparation method of the display substrate shown in fig. 1a to 1d, the method is equivalent to exchanging the sequence of the process for forming the passivation layer 31 and the process for forming the first flat layer 32, forming the supporting structure 37 between the first flat layer 32 and the passivation layer 32, and using the passivation layer as the protective layer 40, so that the protective layer 40 covering the supporting structure 37 is formed, the mask frequency of the display substrate is not increased, the cost is reduced, and the productivity is improved.

It is easily understood that a passivation layer may be formed on the source and drain electrodes, a first planarization layer may be formed on the passivation layer, a support structure may be formed on the first planarization layer, and then a protective layer covering the support structure may be formed, regardless of the number of masks and process costs.

In one embodiment, forming a second planarization layer on the protective layer may include:

forming an intermediate metal layer on the protective layer, wherein the intermediate metal layer penetrates through the protective layer and the first flat layer to be electrically connected with the control structure layer;

and forming a second flat layer on the substrate on which the intermediate metal layer is formed, wherein a fourth through hole exposing the intermediate metal layer is formed on the second flat layer, and the first electrode is electrically connected with the intermediate metal layer through the fourth through hole.

In one embodiment, the method for manufacturing a display substrate may further include:

forming a pixel defining layer on the first electrode, wherein the pixel defining layer is provided with a sub-pixel opening for exposing the first electrode;

and forming a light emitting layer in the sub-pixel opening by an evaporation process.

The technical solution of the embodiment of the present invention is described in detail by the manufacturing process of the display substrate. The "patterning process" in the embodiments includes processes of depositing a thin film, coating a photoresist, exposing a mask, developing, etching, and stripping a photoresist, and is a well-established manufacturing process. The deposition may be performed by a known process such as sputtering, evaporation, chemical vapor deposition, etc., the coating may be performed by a known coating process, and the etching may be performed by a known method, which is not particularly limited herein. "thickness" is the dimension of the film layer in the direction perpendicular to the substrate.

S1: a control structure layer 20 is formed on the substrate. In one embodiment, the control structure layer 20 includes a thin film transistor formed on a substrate, the thin film transistor including an active layer, a gate electrode, a source electrode, and a drain electrode. It is to be understood that the thin film transistor may be a top gate thin film transistor, a bottom gate thin film transistor, or a double gate thin film transistor. In the present embodiment, taking a double-gate thin film transistor as an example, a specific step of forming the control structure layer 20 is described, and the forming the control structure layer 20 on the substrate includes:

s11: referring to fig. 1a, a flexible substrate 11 is formed on a glass substrate 10, and a material of the flexible substrate 11 may include Polyimide (PI). The substrate includes a glass substrate 10 and a flexible substrate 11 formed on the glass substrate 10. The material of the flexible substrate 11 may be Polyimide (PI).

S12: referring to fig. 1a, a buffer layer 12 is formed on a flexible substrate 11; forming an active layer 21 on the buffer layer 12 through a patterning process; forming a first insulating layer 22 on the active layer 21; forming a first gate electrode 23 on the first insulating layer 22 through a patterning process; forming a second insulating layer 24 on the first gate electrode 23; a second gate electrode 25 is formed on the second insulating layer 24 through a patterning process. The buffer layer 12, the first insulating layer 22, and the second insulating layer 24 may be made of silicon nitride SiNx, silicon oxide SiOx, or a composite layer of SiNx/SiOx; the gate electrode can adopt one or more of metals such as platinum Pt, ruthenium Ru, gold Au, silver Ag, molybdenum Mo, chromium Cr, aluminum Al, tantalum Ta, titanium Ti, tungsten W and the like; the material of the active layer 21 may be polysilicon (p-Si).

S13: referring to fig. 1b, a third insulating layer 26 is formed on the glass substrate 10 where the second gate electrode 25 is formed; coating a layer of photoresist on the third insulating layer 26, performing mask exposure and development on the photoresist, removing the photoresist at the first via hole and the second via hole to expose the third insulating layer, and reserving the photoresist at other positions; etching the third insulating layer 26, the second insulating layer 24 and the first insulating layer 22 to form a first via hole and a second via hole exposing the active layer 21; a source electrode 271 and a drain electrode 272 are formed on the third insulating layer 26 through a patterning process, and the source electrode 271 and the drain electrode 272 are electrically connected to the active layer 21 through first and second vias, respectively. The third insulating layer 26 may be a silicon nitride SiNx, a silicon oxide SiOx, or a SiNx/SiOx composite layer, and the source/drain electrodes may be one or more of platinum Pt, ruthenium Ru, gold Au, silver Ag, molybdenum Mo, chromium Cr, aluminum Al, tantalum Ta, titanium Ti, tungsten W, and the like.

S2: forming a first planarization layer 32 on the control structure layer 20, wherein the first planarization layer 32 is provided with a sub-via 321 exposing the drain electrode 272, and the method specifically includes: coating a polymer film on the substrate on which the source and drain electrodes are formed; the polymer film is exposed to a mask and developed to form a first planarization layer 32, and the first planarization layer 32 is formed with a sub-via 321 exposing the drain electrode 272, as shown in fig. 4, where fig. 4 is a schematic structural view of the first planarization layer formed in the first embodiment of the present invention.

S3: forming a support structure 37 on the first planarization layer 32, wherein the material of the support structure 37 includes a negative photosensitive polymer, which specifically includes: a negative photosensitive polymer film is coated on the first planarization layer 32, and the negative photosensitive polymer film is subjected to mask exposure and development to form a support structure 37, as shown in fig. 5, where fig. 5 is a schematic structural view after the support structure is formed in the first embodiment of the present invention. Wherein the angle of inclination of the side 371 of the supporting structure 37 is obtuse, that is, the angle between the side 371 of the supporting structure 37 and the bottom of the supporting structure 37 is obtuse. In one embodiment, the angle θ between the side 371 of the support structure 37 and the bottom edge of the support structure 37 is in the range of 90 to 130, and the height d of the support structure 37 (i.e., the dimension of the support structure in the direction perpendicular to the base) is in the range of 1.0 to 1.5 μm. In order to avoid the influence on the first planarization layer 32 during the formation of the support structure 37, the support structure 37 and the first planarization layer 32 are formed by an exposure and development process, and in one embodiment, the material of the first planarization layer 32 includes a positive photosensitive polymer, such as positive polyimide, so that the first planarization layer 32 is not affected when the support structure is formed by the exposure and development process, and the performance and surface planarity of the first planarization layer 32 are ensured. In a specific implementation, a desired value of θ can be obtained by controlling the intensity and time of exposure.

S4: forming a protective layer 40 covering the support structure 37 on the first planarization layer 32 forming the support structure 37 specifically includes: forming a protective film on the substrate with the support structure 37 by a deposition method, wherein the support structure 37 is coated by the protective film; coating a layer of photoresist on the protective film, exposing and developing the photoresist, removing the photoresist at the position of the sub-via hole 321, and reserving the photoresist at other positions; the protective film is etched to form a third via 401 exposing the drain electrode 272 at the position of the sub-via 321, so as to form a protective layer 40, and the protective layer 40 covers the support structure 37, as shown in fig. 6, where fig. 6 is a schematic structural view after the protective layer is formed in the first embodiment of the present invention. The protective layer 40 may be made of silicon nitride SiNx, silicon oxide SiOx, or a composite layer of SiNx/SiOx. The protective layer 40 covers the supporting structure 37, so that the protective layer 40 can prevent water vapor from entering through the supporting structure 37, the water vapor is effectively isolated, the problem that a subsequently formed light-emitting layer is corroded is avoided, and the display performance of the display substrate is improved. The material of the protection layer 40 is the same as that of the passivation layer, so that the protection layer can also function as the passivation layer, and the passivation layer does not need to be manufactured separately. Compared with the preparation method of the display substrate shown in fig. 1a to 1d, the preparation method of the display substrate according to the embodiment of the invention not only forms the protective layer 40 covering the supporting structure 37, but also uses the protective layer 40 as a passivation layer, so that the number of masks of the display substrate is not increased, the cost is reduced, and the productivity is improved.

In one embodiment, the protective layer 40 has a thickness of 3000 angstroms to 5000 angstroms. Such a thickness not only ensures that the protective layer 40 completely covers the support structure 37, but also avoids that the display substrate finally formed is too high at the position of the support structure 37.

S5: forming the second planarization layer 34 on the protection layer 40 may specifically include:

s51: an intermediate metal layer 33 is formed on the protective layer 40 through a patterning process, and the intermediate metal layer 33 is electrically connected to the drain electrode 272 through the third via 401. The intermediate metal layer 33 may be one or more of platinum Pt, ruthenium Ru, gold Au, silver Ag, molybdenum Mo, chromium Cr, aluminum Al, tantalum Ta, titanium Ti, tungsten W, and the like.

S52: coating a polymer thin film on the substrate on which the intermediate metal layer 33 is formed; the polymer film is exposed through a mask and developed to form a second planarization layer 34, and a fourth via 341 exposing the middle metal layer 33 is formed on the second planarization layer 34, as shown in fig. 7, where fig. 7 is a schematic structural view after the second planarization layer is formed in the first embodiment of the present invention. Because the height of the supporting structure 37 is relatively large, the upper surface of the second flat layer 34 at the position of the supporting structure 37 is higher than the upper surfaces at other positions, and therefore, the second flat layer 34 at the position of the supporting structure 37 can play a role in supporting a mask plate in a subsequent evaporation process. In one embodiment, the material of the second planarization layer 34 includes a positive photosensitive polymer, such as a positive polyimide, etc.

S6: forming a first electrode 35 on the second planarization layer 34, wherein the first electrode 35 is electrically connected to the control structure layer 20 through the second planarization layer 34, the protection layer 40 and the first planarization layer 32, and specifically includes: a first electrode 35 is formed on the second planarization layer 34 through a patterning process, the first electrode 35 is usually an anode, and the first electrode 35 is electrically connected to the intermediate metal layer 33 through a fourth via 341, as shown in fig. 8, where fig. 8 is a schematic structural diagram after the first electrode is formed in the first embodiment of the present invention. Wherein the intermediate metal layer 33 is electrically connected to the drain electrode through the third via 401, such that the first electrode 35 is electrically connected to the control structure layer 20 through the second planarization layer 34, the protection layer 40 and the first planarization layer 32. The first electrode 35 is electrically connected to the drain electrode through the intermediate metal layer 33, so that the first electrode 35 can be prevented from directly penetrating through the second planarization layer 34, the protective layer 40 and the first planarization layer 32 to be electrically connected to the drain electrode, thereby reducing the connection resistance of the first electrode 35 to the drain electrode, and improving the performance of the display substrate.

In one embodiment, the display substrate is an OLED display substrate, and the method for manufacturing the display substrate may further include:

s7: a pixel defining layer 36 is formed on the second planarization layer 34 on which the first electrode 35 is formed, and a sub-pixel opening exposing the first electrode 35 is formed on the pixel defining layer 36. Because the height of the supporting structure 37 is large, the upper surface of the pixel defining layer 36 at the position of the supporting structure 37 is higher than the upper surfaces at other positions, so that the pixel defining layer 36 at the position of the supporting structure 37 can play a role of supporting a mask plate in an evaporation process. In one embodiment, the material of the pixel defining layer 36 includes a positive photosensitive polymer, such as a positive polyimide, and the like.

S8: as shown in fig. 9, a light-emitting layer 38 is formed at the sub-pixel opening by an evaporation process, and fig. 9 is a schematic structural view of the light-emitting layer formed in the first embodiment of the present invention. In the evaporation process, the pixel defining layer 36 located at the position of the supporting structure 37 can be used for supporting the mask plate, so as to ensure the gap between the mask plate and the substrate and improve the evaporation quality of the light-emitting layer.

Second embodiment:

based on the inventive concept of the above embodiments, a second embodiment of the present invention proposes a display substrate, as shown in fig. 9, which includes a base, a control structure layer 20 disposed on the base, a first flat layer 32 disposed on the control structure layer 20, and a support structure 37 disposed on the first flat layer 32. The display substrate further comprises a protective layer 40, the protective layer 40 being disposed on the first planarization layer 32 on which the support structures 37 are formed, the protective layer 40 covering the support structures 37. The second flat layer 34 is disposed on the protection layer 40, the first electrode 35 is disposed on the second flat layer 34, and the first electrode 35 is electrically connected to the control structure layer 20 through the second flat layers 34 and 40 and the first flat layer 32.

In one embodiment, the cross-section of the support structure 37 in the direction perpendicular to the base is inverted trapezoidal, and the width of the top edge of the support structure 37 on the side facing away from the base is greater than the width of the bottom edge of the support structure 37 on the side facing towards the base.

In one embodiment, the angle between the side surface of the support structure and the bottom surface of the support structure facing the substrate side is 90 ° to 130 °.

In one embodiment, the support structure 37 has a dimension in a direction perpendicular to the base of 1.0 μm to 1.5 μm.

In one embodiment, the protective layer has a thickness of 3000 angstroms to 5000 angstroms.

In one embodiment, the material of the first planarization layer comprises positive polyimide.

In one embodiment, the display substrate further includes an intermediate metal layer 33 disposed between the protective layer 40 and the second planarization layer 34, the intermediate metal layer 33 is electrically connected to the control structure layer 20 through the protective layer 40 and the first planarization layer 32, and the first electrode 35 is electrically connected to the intermediate metal layer 33 through the second planarization layer 34. Since the insulating layer between the first electrode and the control structure layer 20 is thick, the intermediate metal layer 33 can reduce the connection resistance between the first electrode 35 and the control structure layer 20, thereby improving the performance of the display substrate.

In one embodiment, the display substrate further includes a pixel defining layer 36 disposed on the first electrode 35, the pixel defining layer 36 defines a sub-pixel opening exposing the first electrode 35, and the sub-pixel opening is disposed with a light emitting layer 38 therein.

The display substrate may be an OLED display substrate including a plurality of pixel units, each pixel unit including an R sub-pixel, a G sub-pixel, and a B sub-pixel. The support structure 37 may be disposed between two adjacent pixel units.

In one embodiment, the support structure is a stripe structure when viewed from the top of the display substrate, and the support structure is disposed between two adjacent columns or two adjacent rows of pixel units.

In another embodiment, the support structure includes a plurality of support pillars sequentially arranged at equal intervals, and the support structure is arranged between two adjacent columns or two adjacent rows of pixel units, as viewed from the top of the display substrate. Each support column is disposed between two adjacent pixel units.

The third embodiment:

based on the inventive concept of the foregoing embodiments, embodiments of the present invention also provide a display device including the display substrate employing the foregoing embodiments. The display device may be: any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator and the like.

In the description of the embodiments of the present invention, it should be understood that the terms "middle", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the term "connected" is to be interpreted broadly, for example, as an electrical connection; either directly or indirectly through intervening media, or may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases by those of ordinary skill in the art.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the form and details of the present invention without departing from the spirit and scope of the invention as defined in the appended claims.