CN110797380A - Display substrate, manufacturing method thereof and display device - Google Patents

Abstract

The invention provides a display substrate, a manufacturing method thereof, and a display device, which belong to the technical field of display. A display substrate, comprising: a base substrate; a driving circuit layer on the base substrate; a flat layer covering the driving circuit layer; a display electrode on the flat layer, the display electrode passing through the flat layer The via hole of the layer overlaps with the output electrode of the driving circuit layer, the output electrode includes a first part in contact with the display electrode and a second part other than the first part, and the display substrate further includes a The spacer structure between the base substrate and the first part, the orthographic projection of the first part on the base substrate is located within the orthographic projection of the spacer structure on the base substrate. The technical scheme of the present invention can improve the overlap between the display electrode and the output electrode, and improve the yield of the display substrate.

Description

Display substrate, manufacturing method thereof, and display device

technical field

The present invention relates to the field of display technology, and in particular, to a display substrate, a manufacturing method thereof, and a display device.

Background technique

In the OLED display substrate, the anode is connected to the drain of the thin film transistor through a via hole passing through the flat layer. Due to the influence of the patterning process of the display substrate, the film layer difference in different areas of the display substrate is large, and a thicker flat layer is required. The display substrate is planarized, so that the depth of the via hole passing through the flat layer is relatively large, which makes it difficult for the anode to overlap with the drain at the via hole, which is prone to poor overlap and affects the display quality of the display substrate.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a display substrate, a manufacturing method thereof, and a display device, which can improve the overlap between the display electrodes and the output electrodes and improve the yield of the display substrate.

In order to solve the above-mentioned technical problems, the embodiments of the present invention provide the following technical solutions:

In one aspect, a display substrate is provided, comprising:

substrate substrate;

a driving circuit layer on the base substrate;

a flat layer covering the driving circuit layer;

a display electrode located on the flat layer, the display electrode overlaps with an output electrode of the driving circuit layer through a via hole penetrating the flat layer, the output electrode includes a first part in contact with the display electrode and a In addition to the second part other than the first part, the display substrate further includes a spacer structure between the base substrate and the first part, the orthographic projection of the first part on the base substrate located in the orthographic projection of the spacer structure on the base substrate.

Optionally, the depth of the via hole is less than the first threshold.

Optionally, the slope angle of the via hole is smaller than the second threshold.

Optionally, at least a part of the spacer structure is made of the same material as the functional film layer in the driving circuit layer.

Optionally, the driving circuit layer includes a pattern of a gate insulating layer and a pattern of a gate metal layer, and the spacer structure includes a first spacer substructure and a second spacer substructure arranged in layers, and the first spacer substructure The same material is used for the gate insulating layer, and the same material is used for the second spacer structure and the gate metal layer.

Optionally, the driving circuit layer further includes a light-shielding metal layer, the spacer structure further includes a third spacer substructure, and the third spacer substructure and the light-shielding metal layer are made of the same material.

Embodiments of the present invention also provide a display device, including the above-mentioned display substrate.

Embodiments of the present invention also provide a method for fabricating a display substrate, including:

providing a base substrate;

forming a driving circuit layer and a spacer structure on the base substrate;

forming a flat layer covering the driving circuit layer and the spacer structure;

forming vias through the planarization layer;

A display electrode is formed on the flat layer, the display electrode is overlapped with the output electrode of the driving circuit layer through the via hole, and the output electrode includes a first part in contact with the display electrode and a second part other than the first part in contact with the display electrode. For a second portion other than a portion, the orthographic projection of the first portion on the base substrate is located within the orthographic projection of the spacer structure on the base substrate.

Optionally, at least a part of the spacer structure and the functional film layer in the driving circuit layer are formed by one patterning process.

Optionally, the driving circuit layer includes a pattern of a gate insulating layer and a pattern of a gate metal layer, and forming the spacer structure includes:

forming a pattern of the first spacer structure and the gate insulating layer through a patterning process;

A pattern of the second spacer structure and the gate metal layer is formed through a patterning process, and the first spacer structure and the second spacer structure are stacked to form the spacer structure.

Embodiments of the present invention have the following beneficial effects:

In the above solution, a spacer structure is arranged between the base substrate and the first part of the output electrode, and the spacer structure can increase the level of the first part, which can reduce the film layer difference in different areas of the display substrate, thereby reducing the flat layer. The thickness of the via hole through the flat layer is further reduced, the connection state between the display electrode and the output electrode at the via hole is optimized, the overlap of the display electrode is improved, and the yield of the display substrate is improved.

Description of drawings

FIG. 1-FIG. 4 are schematic flowcharts of manufacturing a display substrate in the related art;

5 is a schematic diagram after forming a flat layer according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a display substrate according to an embodiment of the present invention.

reference number

1 Substrate substrate

2 buffer layers

3 interlayer insulating layers

4 passivation layer

5 Active layer

6 Conductive active layer

7 Gate insulating layer

8 gate

9 Source

10 shading metal layer

11 Drain

12 Auxiliary Cathode

13 Flat layer

14 Vias

15 Anode

16 Septum Construction

17 Part 1

161 First Septum Structure

162 Second Septum Structure

163 Third Septum Structure

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the embodiments of the present invention clearer, the following detailed description will be given in conjunction with the accompanying drawings and specific embodiments.

The top-gate TFT (thin film transistor) has the characteristics of short channel, so its on-state current Ion can be effectively improved. When applied in a display substrate, the display effect of the display substrate can be significantly improved and the power consumption of the display substrate can be effectively reduced. In addition, the overlapping area between the gate and the source and drain of the top-gate TFT is small, so that the generated parasitic capacitance is small, so the possibility of occurrence of defects such as GDS (gate short circuit between the source and the drain) is also reduced. Since the top-gate TFT has the above-mentioned remarkable advantages, it has attracted more and more attention.

In recent years, large-scale AMOLED (active matrix organic light-emitting diode) display products have been widely used in TV and other fields due to their advantages of high color gamut, high contrast, and self-luminescence. In the production process of large-scale, high-resolution AMOLED display panels such as 8K, due to the extremely high pixel density, if the traditional evaporation method combined with bottom emission is still used, the pixel aperture ratio will be too low to meet the brightness requirements, etc. Therefore, At present, large-scale AMOLED products are mainly produced by the technology of top emission combined with printing primary color light-emitting materials. In order to make the primary color light-emitting material printed on the display substrate more uniform and not interfere with each other, it is necessary to use SOG (organic silicon material) to planarize the display substrate.

FIG. 1-FIG. 4 are schematic diagrams of the process of manufacturing a display substrate in the related art, which specifically includes the following steps:

Step 1. As shown in FIG. 1, a light-shielding metal layer 10 is formed on the base substrate 1, a buffer layer 2 covering the light-shielding metal layer 10 is formed, a pattern of the active layer 5 is formed on the buffer layer 2, and a pattern of the active layer 5 is formed on the buffer layer 2. A gate insulating layer 7 is formed thereon, a gate 8 is formed on the gate insulating layer 7, and the pattern of the active layer 5 is subjected to plasma treatment with the gate 8 as a mask to form a conductive active layer 6; interlayer insulation is formed Layer 3, the source electrode 9 and the drain electrode 11 and the auxiliary cathode 12 are formed on the interlayer insulating layer 3, and the source electrode 9 and the drain electrode 11 are respectively connected with the conductive active layer 6 through the via hole passing through the interlayer insulating layer 3; forming a passivation layer 4;

Step 2: As shown in FIG. 2, a flat layer 13 covering the passivation layer 4 is formed. As can be seen from FIG. 2, due to the influence of the patterning process of the display substrate, the film layer in different areas has a large difference, so it is necessary to use a relatively Only a thick SOG material can perform a good planarization process on the display substrate. At the drain electrode 11 and the auxiliary cathode 12, the thicknesses of the planarization layer 13 are h1 and h2, respectively, which are relatively large;

Step 3: As shown in FIG. 3 , forming a via hole 14 exposing the drain electrode 11 and the auxiliary cathode 12 . Since the thickness of the flat layer 13 at the drain 11 and the auxiliary cathode 12 is relatively large, a thick photoresist needs to be used for protection during via-hole etching and the dry etching time is very long. The appearance slope angle is large, and the dry engraving time is very long, resulting in a large depth of the via hole 14 and a large slope angle;

Step 4. As shown in FIG. 4, an anode 15 is formed on the flat layer 13, and the anode 15 is connected to the drain 11 and the auxiliary cathode 12 through the via 14 respectively. Since the via 14 has a large depth and a large slope angle, the It is difficult for the anode 15 to overlap with the drain 11 and the auxiliary cathode 12 , and poor overlap is likely to occur, thereby seriously affecting the display quality of the display substrate.

In view of the above problems, the embodiments of the present invention provide a display substrate, a manufacturing method thereof, and a display device, which can improve the overlap between the display electrodes and the output electrodes and improve the yield of the display substrate.

Embodiments of the present invention provide a display substrate, including:

substrate substrate;

a driving circuit layer on the base substrate;

a flat layer covering the driving circuit layer;

a display electrode located on the flat layer, the display electrode overlaps with an output electrode of the driving circuit layer through a via hole penetrating the flat layer, the output electrode includes a first part in contact with the display electrode and a In addition to the second part other than the first part, the display substrate further includes a spacer structure between the base substrate and the first part, the orthographic projection of the first part on the base substrate located in the orthographic projection of the spacer structure on the base substrate.

In this embodiment, a spacer structure is arranged between the base substrate and the first part of the output electrode, and the spacer structure can increase the level of the first part, which can reduce the film layer difference in different areas of the display substrate, thereby reducing the flatness The thickness of the layer is reduced, the depth of the via hole passing through the flat layer is reduced, the connection state between the display electrode and the output electrode at the via hole is optimized, the overlap of the display electrode is improved, and the yield of the display substrate is improved.

Wherein, the output electrode is used to provide electrical signals to the display electrode, the display electrode may be an anode, and the output electrode may be a drain of the driving thin film transistor.

In this embodiment, since the film layer difference in different regions of the display substrate is reduced and the thickness of the flat layer is also reduced, the depth of the via hole can be made smaller than the first threshold, specifically, the first threshold is 2-3um.

In addition, due to the reduced thickness of the flat layer, there is no need to apply a thicker photoresist for protection during via etching, the dry etching time can also be shortened, and the slope angle of the via can be reduced, so that the slope angle of the via can be reduced. is less than the second threshold, specifically, the second threshold is 70-85°. The reduction of the slope angle of the via hole can further optimize the connection state between the display electrode and the output electrode at the via hole, improve the overlap of the display electrodes, and improve the yield of the display substrate.

At least a part of the spacer structure and the functional film layer in the driving circuit layer can be made of the same material, so that at least a part of the spacer structure and the functional film layer in the driving circuit layer can be simultaneously formed by using the same patterning process, The number of patterning processes for preparing the display substrate can be reduced, the preparation process of the display substrate can be simplified, and the manufacturing cost of the display substrate can be reduced. Preferably, all of the spacer structures are made of the same material as the functional film layer in the driving circuit layer, so that there is no need to specially manufacture the spacer structures through an additional patterning process.

In a specific example, the driving circuit layer includes a pattern of a gate insulating layer and a pattern of a gate metal layer, the spacer structure includes a first spacer structure and a second spacer structure that are stacked and arranged, the first spacer structure The structure and the gate insulating layer are made of the same material, and the second spacer structure and the gate metal layer are made of the same material, so that the first spacer structure and the gate insulating layer can be formed by one patterning process, and the first spacer structure and the gate insulating layer can be formed by one patterning process. The process forms the second spacer structure and the gate metal layer, and no additional patterning process is required to specially fabricate the spacer structure.

Further, the driving circuit layer further includes a light-shielding metal layer, and the spacer structure further includes a third spacer substructure, and the third spacer substructure and the light-shielding metal layer are made of the same material.

Specifically, the height of the spacer structure can be adjusted according to the film layer step difference of the display substrate, so that the film layer step difference of the display substrate is reduced as much as possible, thereby minimizing the thickness of the flat layer. The spacer structure is not limited to use the same material as the gate insulating layer and the gate metal layer, and can also use the same material as other film layers.

In a specific embodiment, the display substrate is an OLED display substrate, and the display electrode is an anode. As shown in FIG. 5 and FIG. 6 , the display substrate includes a light-shielding metal layer 10 and a third spacer structure 163 on the base substrate 1 to shield light. The metal layer 10 and the third spacer structure 163 are made of the same material and formed by a patterning process; the buffer layer 2 covering the light-shielding metal layer 10; the pattern of the active layer 5 on the buffer layer 2, the pattern of the active layer 5 Both ends of the conductive active layer 6; the gate insulating layer 7 and the first spacer structure 161 located on the active layer 5, wherein, the first spacer structure 161 and the gate insulating layer 7 are made of the same material, and pass through once The patterning process is formed; the gate 8 located on the gate insulating layer 7, the second spacer structure 162 located on the first spacer structure 161, the second spacer structure 162 and the gate 8 are made of the same material, through a patterning process Formed, the first spacer structure 161 and the second spacer structure 162 form the spacer structure 16; the interlayer insulating layer 3; the source electrode 9 and the drain electrode 11, the auxiliary cathode 12, the source electrode 9 located on the interlayer insulating layer 3 and the drain 11 are respectively connected to the conductive active layer 6 through vias penetrating the interlayer insulating layer 3; the passivation layer 4; the flat layer 13 covering the passivation layer 4; the anode 15 on the flat layer 13, the anode 15 The drain electrodes 11 and the auxiliary cathode electrodes 12 are respectively connected through the via holes 14 . In this embodiment, the output electrode includes a drain 11 and an auxiliary cathode 12, the display electrode includes an anode 15, and the spacer structure 16 includes a first spacer substructure 161, a second spacer substructure 162 and a third spacer substructure 163, wherein, The orthographic projection of the first portion 17 of the output electrode on the base substrate falls within the orthographic projection of the spacer structure 16 on the base substrate.

It can be seen from FIG. 5 and FIG. 6 that due to the existence of the spacer structure 16, the film breakage in different areas of the display substrate is reduced, so the display substrate can be well flattened only by using a thinner SOG material. processing, at the drain 11 and the auxiliary cathode 12, the thicknesses of the flat layer 13 are h3 and h4, respectively, both smaller than h1 and h2; since the thickness of the flat layer 13 at the drain 11 and the auxiliary cathode 12 is relatively small, after There is no need to apply thicker photoresist for protection during hole etching, and the dry etching time can also be shortened, which can reduce the depth and slope angle of the via hole 14. Due to the small depth and slope angle of the via hole 14, it can be optimized. The connection state between the anode 15 and the drain 11 and the auxiliary cathode 12 at the hole improves the overlap of the anode 15 and improves the yield of the display substrate.

Embodiments of the present invention also provide a display device, including the above-mentioned display substrate.

The display device includes but is not limited to: a radio frequency unit, a network module, an audio output unit, an input unit, a sensor, a display unit, a user input unit, an interface unit, a memory, a processor, and a power supply and other components. Those skilled in the art can understand that the structure of the above-mentioned display device does not constitute a limitation on the display device, and the display device may include more or less components described above, or combine some components, or arrange different components. In this embodiment of the present invention, the display device includes, but is not limited to, a display, a mobile phone, a tablet computer, a television, a wearable electronic device, a navigation display device, and the like.

The display device can be any product or component with a display function, such as a TV, a monitor, a digital photo frame, a mobile phone, a tablet computer, etc., wherein the display device further includes a flexible circuit board, a printed circuit board and a backplane.

Embodiments of the present invention also provide a method for fabricating a display substrate, including:

providing a base substrate;

forming a driving circuit layer and a spacer structure on the base substrate;

forming a flat layer covering the driving circuit layer and the spacer structure;

forming vias through the planarization layer;

A display electrode is formed on the flat layer, the display electrode is overlapped with the output electrode of the driving circuit layer through the via hole, and the output electrode includes a first part in contact with the display electrode and a second part other than the first part in contact with the display electrode. For a second portion other than a portion, the orthographic projection of the first portion on the base substrate is located within the orthographic projection of the spacer structure on the base substrate.

In this embodiment, a spacer structure is formed between the base substrate and the first part of the output electrode, and the spacer structure can increase the level of the first part, which can reduce the film layer difference in different areas of the display substrate, thereby reducing the level of the flat layer The thickness of the via hole through the flat layer is further reduced, the connection state between the display electrode and the output electrode at the via hole is optimized, the overlap of the display electrode is improved, and the yield of the display substrate is improved.

Optionally, at least a part of the spacer structure and the functional film layer in the driving circuit layer are formed by one patterning process, which can reduce the number of patterning processes for preparing the display substrate, simplify the preparation process of the display substrate, and reduce the display rate. The cost of making the substrate.

Preferably, all of the spacer structures and the functional film layer in the driving circuit layer are formed by the same patterning process, so that there is no need to specially manufacture the spacer structures through an additional patterning process.

In a specific example, the driving circuit layer includes a pattern of a gate insulating layer and a pattern of a gate metal layer, and forming the spacer structure includes:

forming a pattern of the first spacer structure and the gate insulating layer through a patterning process;

A pattern of the second spacer structure and the gate metal layer is formed through a patterning process, and the first spacer structure and the second spacer structure are stacked to form the spacer structure.

Specifically, the height of the spacer structure can be adjusted according to the film layer step difference of the display substrate, so that the film layer step difference of the display substrate is reduced as much as possible, thereby minimizing the thickness of the flat layer. The spacer structure is not limited to use the same material as the gate insulating layer and the gate metal layer, and can also use the same material as other film layers.

In a specific embodiment, as shown in FIG. 5 and FIG. 6 , the manufacturing process of the display substrate specifically includes the following steps:

Step 1. As shown in FIG. 5 , a light-shielding metal layer 10 and a third spacer structure 163 are formed on the base substrate 1, and the light-shielding metal layer 10 and the third spacer structure 163 are formed by one patterning process using the same material;

forming a buffer layer 2 covering the light-shielding metal layer 10 and the third spacer substructure 163;

A pattern of the active layer 5 is formed on the buffer layer 2;

A gate insulating layer 7 and a first spacer substructure 161 are formed on the active layer 5, and the first spacer substructure 161 and the gate insulating layer 7 are formed by one patterning process using the same material;

The gate 8 is formed on the gate insulating layer 7, and the second spacer structure 162 is formed on the first spacer structure 161. The second spacer structure 162 is made of the same material as the gate 8, and is formed through a patterning process. The spacer substructure 161, the second spacer substructure 162 and the third spacer substructure 163 constitute the spacer structure 16;

Using the gate 8 as a mask, plasma treatment is performed on the pattern of the active layer 5 to form the conductive active layer 6;

forming an interlayer insulating layer 3;

A source electrode 9, a drain electrode 11, and an auxiliary cathode 12 are formed on the interlayer insulating layer 3, and the source electrode 9 and the drain electrode 11 are respectively connected to the conductive active layer 6 through vias penetrating the interlayer insulating layer 3;

forming a passivation layer 4;

Step 2: As shown in FIG. 5 , a flat layer 13 covering the passivation layer 4 is formed. As can be seen from FIG. 5 , due to the existence of the spacer structure 16 , the film layer breaks in different areas of the display substrate are reduced, so only the The display substrate can be well planarized by using a thinner SOG material. At the drain electrode 11 and the auxiliary cathode 12, the thicknesses of the planarization layer 13 are h3 and h4, respectively, which are smaller than h1 and h2;

Step 3: As shown in FIG. 6 , forming a via hole 14 exposing the drain electrode 11 and the auxiliary cathode 12 . Since the thickness of the flat layer 13 at the drain 11 and the auxiliary cathode 12 is relatively small, there is no need to apply a thicker photoresist for protection during via etching, the dry etching time can also be shortened, and the via 14 can be reduced. depth and slope angle;

Step 4. As shown in FIG. 6, an anode 15 is formed on the flat layer 13, and the anode 15 is connected to the drain 11 and the auxiliary cathode 12 respectively through the via 14. Due to the small depth and slope angle of the via 14, it can be optimized. The connection state between the anode 15 and the drain 11 and the auxiliary cathode 12 at the hole improves the overlap of the anode 15 and improves the yield of the display substrate.

In the method embodiments of the present invention, the sequence numbers of the steps cannot be used to define the sequence of the steps. For those of ordinary skill in the art, the sequence of the steps can be changed without creative work. It also falls within the protection scope of the present invention.

It should be noted that each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. Especially, for the embodiment, since it is basically similar to the product embodiment, the description is relatively simple, and the relevant part may refer to the partial description of the product embodiment.

Unless otherwise defined, technical or scientific terms used in this disclosure shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. As used in this disclosure, "first," "second," and similar terms do not denote any order, quantity, or importance, but are merely used to distinguish the various components. "Comprises" or "comprising" and similar words mean that the elements or things appearing before the word encompass the elements or things recited after the word and their equivalents, but do not exclude other elements or things. Words like "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "Down", "Left", "Right", etc. are only used to represent the relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, it can be "directly on" or "under" the other element, Or intermediate elements may be present.

In the foregoing description of the embodiments, the particular features, structures, materials or characteristics may be combined in any suitable manner in any one or more of the embodiments or examples.

The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited to this. should be included within the scope of protection of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims (10)

1. A display substrate, comprising:

a substrate base plate;

a driving circuit layer on the substrate base plate;

a planarization layer covering the driving circuit layer;

a display electrode on the flat layer, the display electrode being lapped with the output electrode of the driving circuit layer through a via hole penetrating the flat layer,

the output electrode comprises a first part which is in contact with the display electrode and a second part except the first part, the display substrate further comprises a spacer structure which is positioned between the substrate and the first part, and the orthographic projection of the first part on the substrate is positioned in the orthographic projection of the spacer structure on the substrate.

2. The display substrate of claim 1, wherein a depth of the via is less than a first threshold.

3. The display substrate according to claim 1 or 2, wherein the via hole has a slope angle smaller than a second threshold.

4. The display substrate of claim 1, wherein at least a portion of the spacer structure is made of the same material as the functional film layer in the driving circuit layer.

5. The display substrate according to claim 4, wherein the driving circuit layer comprises a pattern of a gate insulating layer and a pattern of a gate metal layer, and the spacer structure comprises a first spacer structure and a second spacer structure which are stacked, the first spacer structure and the gate insulating layer are made of the same material, and the second spacer structure and the gate metal layer are made of the same material.

6. The display substrate according to claim 5, wherein the driving circuit layer further comprises a light-shielding metal layer, and the spacer structure further comprises a third spacer structure, and the third spacer structure is made of the same material as the light-shielding metal layer.

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

8. A method for manufacturing a display substrate is characterized by comprising the following steps:

providing a substrate base plate;

forming a driving circuit layer and a spacer structure on the substrate base plate;

forming a flat layer covering the driving circuit layer and the spacer structure;

forming a via hole through the planar layer;

and forming a display electrode on the flat layer, wherein the display electrode is overlapped with an output electrode of the driving circuit layer through the via hole, the output electrode comprises a first part contacted with the display electrode and a second part except the first part, and the orthographic projection of the first part on the substrate base plate is positioned in the orthographic projection of the spacer structure on the substrate base plate.

9. The method of manufacturing a display substrate according to claim 8,

and forming at least one part of the spacer structure and the functional film layer in the driving circuit layer by a one-time composition process.

10. The method of claim 9, wherein the driving circuit layer comprises a gate insulating layer pattern and a gate metal layer pattern, and the forming the spacer structure comprises:

forming a first spacer structure and a pattern of the gate insulating layer by a one-time composition process;

and forming a second spacer structure and a pattern of the gate metal layer by a one-time composition process, wherein the first spacer structure and the second spacer structure are stacked to form the spacer structure.

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