LED flip-chip package structure with dummy bumps
View Patent ↗A light-emitting device (LED) package component includes an LED chip having a first active bond pad and a second active bond pad. A carrier chip is bonded onto the LED chip through flip-chip bonding. The carrier chip includes a first active through-substrate via (TSV) and a second active TSV connected to the first and the second active bond pads, respectively. The carrier chip further includes a dummy TSV therein, which is electrically coupled to the first active bond pad, and is configured not to conduct any current when a current flows through the LED chip.
1. A method, comprising:
receiving a first substrate having a light-emitting diode (LED) formed thereon;
receiving a second substrate having a plurality of conductive elements extending through the second substrate, wherein the second substrate includes a non-flat surface; and
bonding the first substrate to the second substrate in a manner such that the LED is thermal-conductively bonded to the plurality of conductive elements of the second substrate.
2. The method of claim 1 , wherein the first substrate contains at least one of:
sapphire, silicon carbide, silicon germanium, and silicon.
3. The method of claim 1 , wherein:
the LED contains a p-type semiconductor layer, an n-type semiconductor layer, and a multiple quantum well disposed between the p-type semiconductor layer and the n-type semiconductor layer; and
the bonding is performed in a manner such that at least one of the conductive elements is electrically coupled to the n-type semiconductor layer, and at least another one of the conductive elements is electrically coupled to the p-type semiconductor layer.
4. The method of claim 1 , wherein at least a subset of the conductive elements are dummy elements configured to be free of electrical current flow.
5. The method of claim 1 , wherein the conductive elements include through-silicon-vias (TSVs).
6. The method of claim 1 , wherein:
the receiving the first substrate includes receiving the first substrate having a plurality of first metal pad thermal-conductively coupled to the LED;
the receiving the second substrate includes receiving the second substrate having a plurality of second metal pads each thermal-conductively coupled to a respective one of the conductive elements of the second substrate; and
the bonding is performed in a manner such that each of the first metal pads is bonded to a respective one of the second metal pads.
7. The method of claim 1 , wherein the bonding includes a flip-chip bonding process.
8. The method of claim 1 , further comprising: forming a lens over the second substrate, the second lens housing the LED therein.
9. The method of claim 1 , further comprising: bonding the second substrate to an electrical packaging device.
10. A method of packaging a light-emitting diode (LED), comprising:
providing an LED chip having a plurality of conductive pads formed thereon, wherein at least a subset of the conductive pads are electrical dummy pads;
providing a carrier substrate having a plurality of through-silicon-vias (TSV) extending from a front surface to a back surface of the carrier substrate;
bonding the LED chip to the carrier substrate such that each of the conductive pads is thermal-conductively coupled to a respective one of the TSVs; and
molding a lens over the carrier substrate and over the LED chip.
11. The method of claim 10 , wherein the providing the LED chip is performed such that the LED chip is formed on a substrate containing one of: a sapphire material, a silicon carbide material, and a silicon germanium material.
12. The method of the claim 10 , wherein the providing the carrier substrate is performed such that the carrier substrate includes a bevel surface.
13. The method of claim 10 , wherein the bonding is performed using a flip-chip bonding process.
14. A method of claim 10 , further comprising: bonding the carrier substrate to a printed circuit board such that the LED chip and the printed circuit board are located on opposite sides of the carrier substrate.
15. A method of forming a light-emitting device (LED) package component, the method comprising:
providing an LED wafer comprising an LED chip, wherein the LED chip comprises a first active bond pad and a second active bond pad;
sawing the LED chip from the LED wafer; and
bonding the first active bond pad and the second active bond pad of the LED chip onto a carrier chip through flip-chip bonding through soldering a first solder bump and a second solder bump, wherein the carrier chip comprises:
a first active through-substrate via (TSV) and a second active TSV configured to electrically connect features on opposite sides of the carrier chip and a dummy TSV;
wherein the first active TSV and the second active TSV are electrically connected to the first solder bump and the second solder bump, respectively; and
wherein the dummy TSV is connected to the LED chip through a dummy solder bump.
16. The method of claim 15 further comprising forming a first solder ball and a second solder ball on the carrier chip and electrically connected to the first active TSV and the second active TSV, respectively, with the first solder ball and a second solder ball being on an opposite side of the carrier chip than the first and the second solder bumps, wherein no solder ball is formed on the dummy TSV.
17. The method of claim 16 , wherein the carrier chip comprises bevel cuts on a same side of the carrier chip as the first solder ball and the second solder ball.
18. The method of claim 15 further comprising, after the step of sawing the LED chip from the LED wafer, forming a bevel cut on an edge of the LED chip.
19. The method of claim 15 , wherein the carrier chip comprises an embedded ohmic line electrically connected to one of the first active TSV and the second active TSV.
20. The method of claim 15 , wherein the carrier chip further comprises a plurality of dummy TSVs between the first active TSV and the second active TSV.
21. The method of claim 15 , wherein the carrier chip includes a non-flat surface.