MICRO LED DISPLAY SUBSTRATE, METHOD FOR MANUFACTURING THE SAME, AND DISPLAY DEVICE

• US 20190326330A1
• Filed: 07/03/2019
• Published: 10/24/2019
• Est. Priority Date: 10/15/2018
• Status: Active Grant

• Current Assignee: Shanghai Tianma Micro-Electronics Company Limited (Tianma Microelectronics Company Limited)
• Original Assignee: Shanghai Tianma Micro-Electronics Company Limited (Tianma Microelectronics Company Limited)
• Inventors: Xia, Xingda, Fu, Jujian, Liu, Gang
• Granted Patent: US 10,964,722 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A Micro LED display substrate, a method for manufacturing the Micro LED display substrate, and a Micro LED display device are provided. In the method, the Micro LED is transferred onto the organic layer of the array substrate, one etching is performed to form through hole on both the protective layer and the array substrate, and then one metal deposition is performed to simultaneously form an electrode of the Micro LED and a structure electrically connecting the graphene layer with the source or drain electrode of the thin film transistor. Compared with the related art in which the electrode of the Micro LED and the structure electrically connecting the graphene layer with the source or drain electrode of the thin film transistor are formed through two etchings and two metal depositions, the method provided by the present disclosure saves the process steps, simplifies the process and reduces the costs.

Claims

1. A method for manufacturing a micro light-emitting diode display substrate, comprising:

forming a graphene layer on a transfer substrate;

forming a semiconductor layer on a surface of the graphene layer facing away from the transfer substrate, and forming a conductive layer on a surface of the semiconductor layer facing away from the transfer substrate, the semiconductor layer and the conductive layer forming a micro light-emitting diode;

forming a protective layer on a surface of the micro light-emitting diode;

providing an array substrate comprising a plurality of thin film transistor structures;

forming an organic layer on the array substrate;

transferring the micro light-emitting diode from the transfer substrate onto the organic layer so that the graphene layer is bonded to the organic layer;

etching the protective layer on the surface of the micro light-emitting diode to form a first through hole exposing the conductive layer, and etching the array substrate to form a second through hole exposing a drain electrode or a source electrode of the plurality of thin film transistor structures through one etching process; and

depositing a conductive metal layer, filling the first through hole and the second through hole and electrically connecting the drain electrode or the source electrode with the graphene layer.

2. The method for manufacturing the micro light-emitting diode display substrate according to claim 1, wherein a projection of the first through hole on the conductive layer has an ring shape in a border region of the micro light-emitting diode;

said etching the protective layer on a surface of the conductive layer to form a first through hole comprises;

forming a photoresist pattern on the protective layer located on the surface of the conductive layer;

photoetching the protective layer located on the surface of the conductive layer so as to remove a portion of the protective layer located on the surface of the conductive layer to form the first through hole whose projection on the conductive layer has the ring shape, the first through hole being distributed in the border region of the micro light-emitting diode.

3. The method for manufacturing the micro light-emitting diode display substrate according to claim 1, wherein the first through hole has an area equal to an area of the conductive layer;

said etching the protective layer on a surface of the conductive layer to form a first through hole comprises;

forming a photoresist pattern on the protective layer located on the surface of the conductive layer;

photoetching the protective layer located on the surface of the conductive layer so as to remove all of the protective layer located on the surface of the conductive layer to form the first through hole having the area equal to the area of the conductive layer.

4. The method for manufacturing the micro light-emitting diode display substrate according to claim 3, wherein said depositing a conductive metal layer filling the first through hole and the second through hole and electrically connecting the drain electrode or the source electrode with the graphene layer comprises:

depositing a conductive metal layer covering the array substrate;

etching the conductive metal layer so as to remove a portion of the conductive metal layer located on the plurality of thin film transistor structures and remove a portion of the conductive metal layer located at a junction between a portion of the conductive metal layer located on the surface of the conductive layer and a portion of the conductive metal layer located on the sidewall of the protective layer, to form a first conductive metal layer filling the first through hole on the surface of the conductive layer, form a second conductive metal layer filling the second through hole, and form a third conductive metal layer surrounding a side wall of the micro light-emitting diode on a surface of the protective layer facing away from the micro light-emitting diode;

wherein the first conductive metal layer is insulated from the third conductive metal layer, and the second conductive metal layer is electrically connected to the graphene layer.

5. The method for manufacturing the micro light-emitting diode display substrate according to claim 1, prior to forming the organic layer on the array substrate, further comprising:

forming a planarization layer on the array substrate.

6. The method for manufacturing the micro light-emitting diode display substrate according to claim 1, wherein said transferring the micro light-emitting diode from the transfer substrate onto the organic layer comprises:

adsorbing, by a transfer device, a surface of the protective layer facing away from the conductive layer so as to transfer the micro light-emitting diode from the transfer substrate onto a portion of the organic layer located on a region of the array substrate without the plurality of thin film transistor structures.

7. The method for manufacturing the micro light-emitting diode display substrate according to claim 6, wherein said adsorbing, by a transfer device, a surface of the protective layer facing away from the conductive layer comprises:

adsorbing the surface of the protective layer facing away from the conductive layer by means of adhesion;

or

adsorbing the surface of the protective layer facing away from the conductive layer by means of vacuum adsorption.

8. The method for manufacturing the micro light-emitting diode display substrate according to claim 1, wherein said forming a semiconductor layer on a surface of the graphene layer facing away from the transfer substrate, and forming a conductive layer on a surface of the semiconductor layer facing away from the transfer substrate, the semiconductor layer and the conductive layer forming a micro light-emitting diode comprises:

forming a first type semiconductor layer on the surface of the graphene layer facing away from the transfer substrate;

forming an active layer on a surface of the first type semiconductor layer facing away from the graphene layer;

forming a second type semiconductor layer on a surface of the active layer facing away from the first type semiconductor layer; and

forming the conductive layer on a surface of the second type semiconductor layer facing away from the active layer.

9. The method for manufacturing the micro light-emitting diode display substrate according to claim 8, wherein the first type semiconductor layer is an N-type semiconductor layer, and the second type semiconductor layer is a P-type semiconductor layer.

10. A micro light-emitting diode display substrate, comprising:

an array substrate comprising a plurality of thin film transistor structures arranged in an array;

an organic layer located on a surface of the array substrate;

a graphene layer provided on a surface of the organic layer facing away from the array substrate;

a micro light-emitting diode located on a surface of the graphene layer facing away from the array substrate;

a protective layer located on a surface of the micro light-emitting diode; and

a conductive metal layer, wherein the conductive metal layer comprises a first conductive metal layer portion penetrating through the protective layer and electrically connected to the conductive layer of the micro light-emitting diode, and a second conductive metal layer portion electrically connecting the graphene layer and a drain electrode or a source electrode of the plurality of thin film transistor structures.

11. The micro light-emitting diode display substrate according to claim 10, wherein the conductive metal layer further comprises:

a third conductive metal layer portion surrounding a side wall of the micro light-emitting diode,

wherein the first conductive metal layer portion is insulated from the third conductive metal layer portion.

12. The micro light-emitting diode display substrate according to claim 10, wherein an area of the first conductive metal layer portion is equal to an area of the conductive layer of the micro light-emitting diode.

13. The micro light-emitting diode display substrate according to claim 10, wherein the first conductive metal layer portion is arranged in a border region of the micro light-emitting diode.

14. The micro light-emitting diode display substrate according to claim 13, wherein a projection of the first conductive metal layer portion on the array substrate has a circular ring shape or a rectangular ring shape.

15. The micro light-emitting diode display substrate according to claim 10, further comprising an electrical interconnection structure;

wherein the electrical interconnection structure electrically connects first conductive metal layer portions in a plurality of micro light-emitting diodes, each first conductive metal layer portion penetrating through the protective layer and electrically connected to the conductive layer of one of the plurality of micro light-emitting diodes; and

the electrical interconnection structure and the conductive metal layer are formed in a same process.

16. A micro light-emitting diode display device, comprising:

a micro light-emitting diode display substrate, wherein the micro light-emitting diode display substrate comprises;

an array substrate comprising a plurality of thin film transistor structures arranged in an array;

an organic layer located on a surface of the array substrate;

a graphene layer provided on a surface of the organic layer facing away from the array substrate;

a micro light-emitting diode located on a surface of the graphene layer facing away from the array substrate;

a protective layer located on a surface of the micro light-emitting diode; and

a conductive metal layer, wherein the conductive metal layer comprises a first conductive metal layer portion penetrating through the protective layer and electrically connected to the conductive layer of the micro light-emitting diode, and a second conductive metal layer portion electrically connecting the graphene layer and a drain electrode or a source electrode of the plurality of thin film transistor structures.