Testable Flip-Chip Micro-Light Emitting Diode (LED) Devices

1 . A micro-light emitting diode (uLED) device comprising:

a plurality of micro-light emitting diodes (uLEDs), each of the uLEDs comprising:

a pixel;

an N-contact in contact with the pixel and having an N-contact top surface;

a P-contact in contact with the pixel and having a P-contact top surface;

an N-contact test pad on the N-contact top surface and having an N-contact test pad surface; and

a P-contact test pad on the P-contact top surface and having a P-contact test pad surface; and

a primary release layer positioned between all of the N-contacts and P-contacts of the uLEDs.

2 . The uLED device of claim 1 , wherein a first surface area of the N-contact test pad surface is larger than a second surface area of the N-contact top surface and a third surface area of the P-contact test pad surface is larger than a fourth surface area of the P-contact top surface.

3 . The uLED device of claim 1 , wherein the primary release layer comprises a photoresist material.

4 . The uLED device of claim 3 , wherein the photoresist material comprises polydimethylglutarimide (PMGI) and/or a cyclopentanone-based polymer.

5 . The uLED device of claim 1 further comprising a secondary release layer covering all of the N-contact test pads and the P-contact test pads.

6 . The uLED device of claim 5 , wherein the secondary release layer comprises a photoresist material.

7 . The uLED device of claim 1 , wherein each of the N-contacts and the P-contacts comprise one or more of: aluminum (Al), nickel (Ni), titanium (Ti), gold (Au), platinum (Pt), and palladium (Pd).

8 . The uLED device of claim 1 , wherein each of the N-contact test pad and the P-contact test pad comprises one or more of: copper (Cu), aluminum (Al), nickel (Ni), titanium (Ti), titanium-tungsten (TiW), silver (Ag), gold (Au), platinum (Pt), and palladium (Pd).

9 . The uLED device of claim 1 further comprising a device substrate that supports the pixel.

10 . The uLED device of claim 9 , wherein the device substrate comprises: a material selected from the group consisting of: a sapphire, silicon carbide, and III-nitride.

11 . A method of manufacturing a micro-light emitting diode (uLED) device, the method comprising:

depositing a primary release material on an array of micro-light emitting diodes (uLEDs), each uLED comprising: a pixel, an N-contact, and a P-contact, each of the N-contacts and the P-contacts in contact with each of the pixels;

etching the primary release material to expose each of the N-contacts and the P-contacts, thereby forming a primary release layer; and

preparing an N-contact test pad on each of the N-contacts and a P-contact test pad on each of the P-contacts.

12 . The method of claim 11 , wherein preparing the N-contact test pads and the P-contact test pads comprises: depositing a test pad material on the array; and patterning the test pad material.

13 . The method of claim 11 , wherein preparing the N-contact test pads and the P-contact test pads comprises: depositing a mask material in a pattern on the array, depositing a test pad material, and removing the mask material.

14 . The method of claim 11 , wherein a first surface area of an N-contact test pad surface is larger than a second surface area of an N-contact top surface and a third surface area of a P-contact test pad surface is larger than a fourth surface area of a P-contact top surface.

15 . The method of claim 11 , wherein each of the N-contacts and the P-contacts comprise one or more of: aluminum (Al), nickel (Ni), titanium (Ti), gold (Au), platinum (Pt), and palladium (Pd); and/or the N-contact test pads and the P-contact test pads comprise one or more of: copper (Cu), aluminum (Al), nickel (Ni), titanium (Ti), titanium-tungsten (TiW), silver (Ag), gold (Au), platinum (Pt), and palladium (Pd).

16 . The method of claim 11 , wherein the test pad material is deposited by an evaporation or sputtering process or a combination of both evaporation and sputtering to a thickness of less than or equal to 2 micrometers.

17 . The method of claim 11 , wherein the primary release layer comprises a photoresist material.

18 . The method of claim 11 further comprising removing the N-contact test pads and the P-contact test pads.

19 . The method of claim 11 further comprising depositing a secondary release layer covering all of the N-contact test pads and the P-contact test pads.

20 . The method of claim 19 further comprising removing the secondary release layer.