Bump bonding structure to mitigate space contamination for III-V dies and CMOS dies

1. A vertical cavity surface emitting laser (VCSEL) device, comprising:

a bond bump overlying a substrate;

a VCSEL structure overlying the bond bump, the VCSEL structure comprises a second reflector overlying an optically active region and a first reflector underlying the optically active region, wherein the bond bump directly underlies a middle region of the VCSEL structure; and

a bond ring overlying the substrate and laterally separated from the bond bump, wherein the bond ring continuously extends around the bond bump, wherein a bottom surface of the bond bump is aligned with a bottom surface of the bond ring and a top surface of the bond bump is aligned with a top surface of the bond ring.

2. The VCSEL device of claim 1 , wherein the bond ring and the bond bump respectively comprise a same material.

3. The VCSEL device of claim 2 , wherein the same material is gold.

4. The VCSEL device of claim 1 , wherein outer sidewalls of the bond bump are laterally disposed between outer sidewalls of the VCSEL structure.

5. The VCSEL device of claim 1 , wherein the bond bump and bond ring respectively overlie a bond seed layer, the bond seed layer comprises a same material as the bond bump and the bond ring.

6. The VCSEL device of claim 1 , further comprising:

a conductive via extending from a contact pad to an upper surface of the second reflector, wherein the conductive via is laterally between the VCSEL structure and the bond ring.

7. The VCSEL device of claim 6 , further comprising:

a second VCSEL structure disposed over another bond bump, wherein the bond ring continuously extends along an unbroken path around the bond bump and the another bond bump.

8. The VCSEL device of claim 6 , further comprising:

a second conductive via extending from a second contact pad to the upper surface of the second reflector, wherein the VCSEL structure is laterally between the conductive via and the second conductive via, and wherein the conductive via and the second conductive via are laterally between inner sidewalls of the bond ring.

9. The VCSEL device of claim 1 , further comprising:

a stack of bonding layers disposed between the VCSEL structure and the bond bump, wherein a bottommost bonding layer in the stack of bonding layers comprises a same material as the bond ring.

10. The VCSEL device of claim 1 , wherein the bond bump is spaced laterally between opposing sidewalls of the optically active region.

11. The VCSEL device of claim 1 , further comprising:

a dielectric structure overlying the bond ring, wherein the dielectric structure continuously extends from a first sidewall of the bond ring, along the top surface of the bond ring, to a second sidewall of the bond ring.

12. The VCSEL device of claim 11 , wherein a bottom surface of the dielectric structure is disposed below the top surface of the bond ring.

13. A semiconductor chip comprising:

a plurality of semiconductor devices disposed over a substrate;

an interconnect structure disposed over and electrically coupled to the semiconductor devices;

a plurality of bond bumps overlying the interconnect structure;

a plurality of vertical cavity surface emitting laser (VCSEL) structures, wherein the VCSEL structures respectively overlie the bond bumps;

a stack of bonding layers disposed between the VCSEL structures and the bond bumps;

a bond ring surrounding the plurality of bond bumps, wherein the VCSEL structures and the bond bumps are laterally separated from the bond ring by one or more non-zero distances;

a bond seed layer disposed between the interconnect structure and the bond ring; and

a pair of conductive vias respectively extending from the interconnect structure to an upper surface of a corresponding VCSEL structure, wherein a bottom surface of the pair of conductive vias are aligned with a bottom surface of the bond seed layer.

14. The semiconductor chip of claim 13 , wherein the bond bumps, bond ring, and bottommost bonding layer respectively comprise a same material.

15. The semiconductor chip of claim 14 , wherein the same material is gold.

16. The semiconductor chip of claim 13 , wherein the bond bumps respectively have an octagonal shape when viewed from above and the bond ring has a rectangular shape when viewed from above.

17. A method for forming a vertical cavity surface emitting laser (VCSEL) device comprising:

providing a complementary metal-oxide-semiconductor (CMOS) substrate having an interconnect structure overlying the CMOS substrate;

forming bond bumps and bond rings over the interconnect structure;

bonding first and second III-V dies respectively to the bond rings, the bonding process seals a first cavity between the first III-V die and the interconnect structure, and seals a second cavity between the second III-V die and the interconnect structure;

forming a molding layer around the first and second III-V dies, wherein the bond rings block the molding layer from being formed below the first and second III-V dies;

removing the molding layer; and

forming VCSEL structures over each bond bump, wherein outer sidewalls of the VCSEL structures are laterally between inner sidewalls of one of the bond rings.

18. The method of claim 17 , further comprising:

forming an epitaxial III-V structure on a first face of a carrier substrate, and a stack of bonding layers over the epitaxial III-V structure; and

removing parts of the carrier substrate and the epitaxial III-V structure to define the first III-V die and the second III-V die.

19. The method of claim 18 , further comprising:

bringing an upper surface of a bonding layer disposed along a top of the first III-V die into contact with a first one of the bond rings and a first one of the bond bumps, wherein the bonding layer has an upper surface that continuously extends between outermost sidewalls of the first one of the bond rings.

20. The method of claim 17 , wherein during the bonding process outer sidewalls of the first and second III-V dies are aligned with outer sidewalls of the respective bond ring.