Display substrate, manufacturing method thereof, display panel, and display device

1. A method for manufacturing a display substrate, comprising:

forming a thin film transistor on a base substrate;

forming a planarization layer covering the thin film transistor;

forming a metal mask layer on the planarization layer;

patterning the metal mask layer to form an etching hole in the metal mask layer, the etching hole exposing a portion of the planarization layer;

etching the portion of the planarization layer exposed by the etching hole to form a first via hole penetrating the planarization layer;

removing a remaining metal mask layer on the planarization layer;

forming, above the base substrate, a passivation layer covering the thin film transistor prior to forming the planarization layer; and

etching a portion of the passivation layer corresponding to the etching hole to form a second via hole penetrating the passivation layer, the second via hole communicating with the first via hole, wherein a material of the metal mask layer comprises Cu or AlNd.

2. The method according to claim 1 , wherein a process of forming the first via hole and removing the remaining metal mask layer comprises:

etching the portion of the planarization layer exposed by the etching hole using a first etching process to form the first via hole; and

removing the remaining metal mask layer on the planarization layer using a second etching process different from the first etching process.

3. The method according to claim 2 , wherein a process of forming the second via hole comprises:

coating a photoresist on the planarization layer where the remaining metal mask layer has been removed;

patterning the photoresist to expose the first via hole;

etching a portion of the passivation layer exposed by the first via hole using a third etching process to form the second via hole; and

removing the photoresist on the planarization layer.

4. The method according to claim 3 , wherein the first etching process and the third etching process both comprise a dry etching process using a mixed gas of CF 4 and O 2 as an etching gas, wherein the second etching process comprises a wet etching process using an acidic solution as an etching solution.

5. The method according to claim 4 , wherein a gas flow ratio of CF 4 to O 2 in the mixed gas is 4:1 to 5:1.

6. The method according to claim 1 , wherein the metal mask layer has a thickness ranging from 3000 Å to 5000 Å.

7. The method according to claim 1 , wherein a thickness of the passivation layer is smaller than a thickness of the planarization layer.

8. The method according to claim 1 , wherein an orthographic projection of the etching hole on the base substrate at least partially overlaps an orthographic projection of a source or a drain of the thin film transistor on the base substrate.

9. The method according to claim 1 , wherein a process of forming the thin film transistor on the base substrate comprises:

forming a light shielding layer on the base substrate by a patterning process;

forming a buffer layer covering the light shielding layer;

forming an active layer on the buffer layer by a patterning process;

forming a gate insulating layer and a gate successively on the active layer by a patterning process;

forming an interlayer dielectric layer by a patterning process, the interlayer dielectric layer covering the buffer layer, the active layer, the gate insulating layer and the gate; and

forming a source and a drain on the interlayer dielectric layer by a patterning process, the source and the drain being connected to the active layer through via holes in the interlayer dielectric layer respectively.

10. A display substrate manufactured by the method for manufacturing a display substrate according to claim 1 , wherein the first via hole and the second via hole communicate with each other, and a size of a top opening of the first via hole is greater than a size of a top opening of the second via hole.

11. The display substrate according to claim 10 , wherein a slope angle of the first via hole is smaller than a slope angle of the second via hole.

12. A display panel comprising the display substrate according to claim 10 .

13. A display device comprising the display panel according to claim 12 .

14. A method for manufacturing a display substrate, comprising:

forming a thin film transistor on a base substrate;

forming a planarization layer covering the thin film transistor;

forming a metal mask layer on the planarization layer;

patterning the metal mask layer to form an etching hole in the metal mask layer, the etching hole exposing a portion of the planarization layer;

etching the portion of the planarization layer exposed by the etching hole to form a first via hole penetrating the planarization layer;

removing a remaining metal mask layer on the planarization layer;

forming, above the base substrate, a passivation layer covering the thin film transistor prior to forming the planarization layer; and

etching a portion of the passivation layer corresponding to the etching hole to form a second via hole penetrating the passivation layer, the second via hole communicating with the first via hole, wherein a material of the metal mask layer comprises Au.

15. The method according to claim 14 , wherein a process of forming the first via hole and the second via hole and removing the remaining metal mask layer comprises:

etching the portion of the planarization layer exposed by the etching hole and a portion of the passivation layer corresponding to the etching hole using a fourth etching process to form the first via hole and the second via hole communicating with each other; and

removing the remaining metal mask layer on the planarization layer using a fifth etching process different from the fourth etching process.

16. The method according to claim 15 , wherein the fourth etching process comprises a dry etching process using a mixed gas of CF 4 and O 2 as an etching gas, wherein the fifth etching process comprises a wet etching process using a mixed solution of I 2 , KI and water as an etching solution.