Method of manufacturing micro-LED array display devices with CMOS cells
Micro-LED array display devices are disclosed. One of the micro-LED display devices includes: a micro-LED panel including a plurality of micro-LED pixels; a CMOS backplane including a plurality of CMOS cells corresponding to the micro-LED pixels to individually drive the micro-LED pixels; and bumps electrically connecting the micro-LED pixels to the corresponding CMOS cells in a state in which the micro-LED pixels are arranged to face the CMOS cells. The micro-LED pixels are flip-chip bonded to the corresponding CMOS cells formed on the CMOS backplane through the bumps so that the micro-LED pixels are individually controlled.
1. A method for fabricating a micro-LED array display device comprising:
preparing a micro-LED panel comprising a substrate and a plurality of micro-LED pixels formed on the substrate by growing a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer in order on the substrate and removing the active layer and the second conductivity-type semiconductor layer in predetermined portions to expose the first conductivity-type semiconductor layer, whereby the micro-LED pixels have a vertical structure including the first conductivity-type semiconductor layer, the active layer, and the second conductivity-type semiconductor layer in order on the substrate and none of the micro-LED pixels is formed on the substrate in the exposed portions, wherein a first conductivity-type metal layer is formed over a portion of the exposed portions of the first conductivity-type semiconductor layer, the first conductivity-type metal layer being spaced apart from the micro-LED pixels and functioning as a common electrode of the micro-LED pixels, the first conductivity-type metal layer being formed along the periphery of the micro-LED panel on the first conductivity-type semiconductor layer;
preparing a CMOS backplane comprising a plurality of CMOS cells corresponding to the micro-LED pixels;
arranging bumps electrically connecting the micro-LED pixels to the corresponding CMOS cells in a state in which the micro-LED pixels are arranged to face the CMOS cells; and
heating the bumps in a state in which the bumps is interposed between the micro-LED pixels and the CMOS cells corresponding to the micro-LED pixels.
2. The method according to claim 1 , wherein the first conductivity-type metal layer has the same height as the micro-LED pixels.
3. The method according to claim 1 , wherein the CMOS backplane comprises a common cell formed at a position corresponding to the first conductivity-type metal layer and the first conductivity-type metal layer is electrically connected to the common cell through a common bump.
4. The method according to claim 3 , wherein the common bump is formed along the periphery of the CMOS cells on the common cell.
5. The method according to claim 1 , wherein the micro LED pixels are individually flip-bonded to the CMOS cells so that the micro-LED are individually controlled.
6. The method according to claim 1 , wherein the first conductivity-type is n-type and the second conductivity-type is p-type.
7. The method according to claim 1 , wherein the substrate is made of a material selected from sapphire, SiC, Si, glass, and ZnO.
8. The method according to claim 1 , wherein the step of arranging the bumps comprises placing the substrate of the micro-LED panel having the micro-LED pixels over the CMOS backplane, so that the micro-LED pixels formed in the substrate face the corresponding CMOS cells of the CMOS backplane.
9. A method for fabricating a micro-LED array display device comprising:
preparing first, second, and third micro-LED panels emitting light of different wavelength bands, each of the micro-LED panels comprising a substrate and a plurality of micro-LED pixels on the substrate by growing a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer in order on the substrate of the corresponding first, second, and the third micro-LED panels and removing the active layer and the second conductivity-type semiconductor layer in predetermined portions to expose the first conductivity-type semiconductor layer, whereby the micro-LED pixels of each of the first, second, and third micro-LED panels have a vertical structure including the first conductivity-type semiconductor layer, the active layer, and the second conductivity-type semiconductor layer in order on the substrate of the corresponding first, second, and third micro-LED panels and none of the micro-LED pixels is formed on the substrate in the exposed portions, wherein a first conductivity-type metal layer is formed over a portion of the exposed portions of the first conductivity-type semiconductor layer of each of the first, second and third micro-LED panels, the first conductivity-type metal layer being spaced apart from the micro-LED pixels of each of the first, second, and third micro-LED panels and functioning as a common electrode of the micro-LED pixels, the first conductivity-type metal layer of each of the first, second, and third micro-LED panels being formed along the periphery of each of the first, second, and third micro-LED panels on the first conductivity-type semiconductor layer of each of the first, second, and third micro-LED panels;
preparing a single CMOS backplane comprising a plurality of CMOS cells corresponding to the micro-LED pixels;
arranging bumps electrically connecting the micro-LED pixels of the first, second, and third micro-LED panels to the corresponding CMOS cells in a state in which the micro-LED pixels of the first, second, and third micro-LED panels are arranged to face the CMOS cells; and
heating the bumps in a state in which the bumps is interposed between the micro-LED pixels and the CMOS cells corresponding to the micro-LED pixels.
10. The method according to claim 9 , wherein the first conductivity-type metal layer of each of the first, second, and third micro-LED panels has the same height as the micro-LED pixels of the first, second, and third micro-LED panels.
11. The method according to claim 9 , wherein the single CMOS backplane comprises a common cell formed at a position corresponding to the first conductivity-type metal layer of each of the first, second, and third micro-LED panels and the first conductivity-type metal layer is electrically connected to the common cell through a common bump.
12. The method according to claim 11 , wherein the common bump is formed along the periphery of the CMOS cells on the common cell.
13. The method according to claim 9 , wherein the micro LED pixels are individually flip-bonded to the CMOS cells so that the micro-LED are individually controlled.
14. The method according to claim 9 , wherein the micro-LED display device is capable of implementing full color, wherein the first micro-LED panel emits red color, the second micro-LED display emits green color, and the third micro-LED panel emits blue color.
15. The method according to claim 9 , wherein the micro-LED display device further comprises a drive IC, and a control signal from the drive IC is supplied to the micro-LED pixel through the corresponding CMOS cell.
16. The method according to claim 9 , wherein the first conductivity-type is n-type and the second conductivity-type is p-type.
17. The method according to claim 9 , wherein the substrate is made of a material selected from sapphire, SiC, Si, glass, and ZnO.
18. The method according to claim 9 , wherein the step of arranging the bumps comprises placing the substrate of each of the first, second, and third micro-LED panels having the micro-LED pixels over the CMOS backplane, so that the micro-LED pixels formed in the substrate of each of the first, second, and third micro-LED panels face the corresponding CMOS cells of the CMOS backplane.