Method of bonding a semiconductor device using a compliant bonding structure
View Patent ↗A compliant bonding structure is disposed between a semiconductor device and a mount. In some embodiments, the device is a light emitting device. When the semiconductor light emitting device is attached to the mount, for example by providing ultrasonic energy to the semiconductor light emitting device, the compliant bonding structure collapses to partially fill a space between the semiconductor light emitting device and the mount. In some embodiments, the compliant bonding structure is plurality of metal bumps that undergo plastic deformation during bonding. In some embodiments, the compliant bonding structure is a porous metal layer.
1. A method comprising:
disposing a compliant bonding structure between a semiconductor device and a mount, wherein the compliant bonding structure comprises a plurality of metal bumps; and
bonding the semiconductor device to the mount, wherein:
bonding causes the compliant bonding structure to collapse such that the compliant bonding structure electrically and mechanically connects the semiconductor device to the mount;
the compliant bonding structure remains in a solid phase during bonding; and
bonding causes the plurality of metal bumps to deform such that most or all of the area between the semiconductor device and the mount where the plurality of metal bumps are formed is filled with material from the plurality of metal bumps, leaving no gaps between adjacent bumps or gaps less than 2 microns wide between adjacent bumps.
2. The method of claim 1 wherein a height of the compliant bonding structure after bonding is less than 50% of an original height of the compliant bonding structure.
3. The method of claim 1 wherein the semiconductor device comprises:
a semiconductor structure comprising a light emitting region disposed between an n-type region and a p-type region;
an n-metal structure disposed on a portion of the n-type region; and
a p-metal structure disposed on a portion of the p-type region.
4. The method of claim 1 wherein the plurality of metal bumps comprise a metal with a Young's modulus less than 150 GPa.
5. The method of claim 1 wherein:
the plurality of metal bumps each have a width between 6 and 25 microns and a height between 6 and 25 microns;
nearest neighbor bumps are spaced between 6 and 25 microns apart.
6. The method of claim 1 wherein the plurality of metal bumps are gold bumps.
7. The method of claim 3 wherein:
the n-metal structure comprises a gold layer at least ten microns thick;
a portion of the plurality of metal bumps are formed on the n-metal structure;
the p-metal structure comprises a gold layer at least ten microns thick; and
a portion of the plurality of metal bumps are formed on the p-metal structure.
8. The method of claim 1 wherein in a first region of the semiconductor structure, nearest neighbor bumps are more closely spaced than nearest neighbor bumps in a second region of the semiconductor structure.
9. The method of claim 3 wherein after bonding the collapsed metal bumps have a height less than 20% of a height of at least one of the plurality of metal bumps.
10. The method of claim 3 wherein the semiconductor light emitting device further comprises a growth substrate, the method further comprising removing the growth substrate after bonding.
11. The method of claim 3 wherein a portion of the compliant bonding structure proximate to an edge of the semiconductor light emitting device is configured such that during bonding, the portion of the compliant bonding structure collapses to form a seal between the semiconductor light emitting device and the mount.
12. The method of claim 11 wherein the portion of the compliant bonding structure proximate to an edge of the semiconductor light emitting device comprises a continuous, linear metal bump.
13. The method of claim 11 wherein the portion of the compliant bonding structure proximate to an edge of the semiconductor light emitting device comprises a continuous, curved metal bump.
14. The method of claim 11 wherein the portion of the compliant bonding structure proximate to an edge of the semiconductor light emitting device comprises at least two lines of metal bumps, wherein the at least two lines of metal bumps are offset such that during bonding, the at least two lines of metal bumps collapse to form a continuous seal.
15. The method of claim 1 wherein after bonding, a space between the semiconductor device and the mount is at least 85% filled with deformed metal bumps.