Wafer level LED package and method of fabricating the same
View Patent ↗Disclosed are a wafer level LED package and a method of fabricating the same. The method of fabricating a wafer level LED package includes: forming a plurality of semiconductor stacks on a first substrate, each of the semiconductor stacks comprising a first-conductivity-type semiconductor layer, a second-conductivity-type semiconductor layer, and an active region disposed between the first-conductivity-type semiconductor layer and the second-conductivity-type semiconductor layer; preparing a second substrate comprising first lead electrodes and second lead electrodes arranged corresponding to the plurality of semiconductor stacks; bonding the plurality of semiconductor stacks to the second substrate; and cutting the first substrate and the second substrate into a plurality of packages after the bonding is completed. Accordingly, the wafer level LED package is provided.
1. A method of fabricating a light emitting diode (LED) package, comprising:
forming a plurality of semiconductor stacks on a first substrate, each semiconductor stack comprising a first semiconductor layer, a second semiconductor layer, and an active region disposed between the first semiconductor layer and the second semiconductor layer;
coupling the plurality of semiconductor stacks to a second substrate, the second substrate comprising first lead electrodes and second lead electrodes arranged corresponding to the plurality of semiconductor stacks;
cutting the first substrate and the second substrate into a plurality of packages after the coupling is completed; and
forming an underfill covering the plurality of semiconductor stacks,
wherein the first bumps and the second bumps pass through the underfill, and
wherein the underfill contacts the second substrate.
2. The method of claim 1 , further comprising:
forming first bumps and second bumps on the first semiconductor layers and the second semiconductor layers of the semiconductor stacks, respectively; and
coupling the first bumps and the second bumps to the first lead electrodes and the second lead electrodes, respectively, so that the plurality of semiconductor stacks are coupled to the first lead electrodes and the second lead electrodes.
3. The method of claim 1 , wherein the underfill comprises at least one of a phosphor and a filler.
4. The method of claim 1 , wherein the forming of the underfill comprises:
forming a B-stage underfill on the first substrate to cover the plurality of semiconductor stacks; and
curing the B-stage underfill while the first and second bumps are coupled to the first and second lead electrodes.
5. The method of claim 1 , further comprising:
forming a wavelength converter covering a rear surface of the first substrate after the coupling is completed.
6. The method of claim 5 , wherein the wavelength converter is formed to cover a lateral side of the first substrate after the cutting of the first substrate.
7. The method of claim 6 , further comprising:
partially removing a portion of the underfill disposed under a cut region after the cutting of the first substrate,
wherein the wavelength converter is formed to cover a lateral side exposed by the partial removal of the underfill.
8. The method of claim 7 , further comprising:
forming a moisture barrier coating covering the wavelength converter.
9. The method of claim 8 , wherein the moisture barrier coating is formed such that the wavelength converter is buried within the package.
10. The method of claim 1 , further comprising:
forming a wavelength converter covering a rear surface of the first substrate after the coupling is completed.
11. The method of claim 10 , wherein the wavelength converter comprises a phosphor-containing glass.
12. The method of claim 11 , wherein the glass is attached to the substrate by a low-temperature direct bonding.
13. The method of claim 10 , further comprising:
forming a moisture barrier coating covering the wavelength converter.
14. The method of claim 13 , wherein the moisture barrier coating is formed by alternately laminating an organic material layer and an inorganic material layer.
15. The method of claim 10 , wherein the wavelength converter is formed after the cutting of the first substrate.
16. The method of claim 15 , wherein the wavelength converter fills a gap between the plurality of semiconductor stacks and the second substrate.
17. The method of claim 16 , further comprising:
cutting the wavelength converter on a package basis by removing the wavelength converter disposed under the cut region of the first substrate; and
forming a moisture barrier coating covering the cut wavelength converter.
18. The method of claim 1 , further comprising:
forming a surface texture on a rear surface of the first substrate so as to improve a light extraction efficiency.
19. The method of claim 1 , wherein the first substrate is cut such that a lateral side of the first substrate is inclined with respect to a vertical direction of a rear surface of the first substrate.
20. The method of claim 1 , wherein the top surface of the first and second lead electrodes are disposed entirely within the contact area of the first and second bumps, respectively.
21. The method of claim 1 , wherein the second substrate comprises only a first and second lead electrode corresponding to each semiconductor stack.