Self-aligned carrier assembly for optical device supporting wafer scale methods
View Patent ↗Broadly speaking, disclosed is a carrier assembly for an optical device, the carrier assembly comprising in combination: a glass substrate with an optical die thereon; and a silicon carrier attached to the glass carrier. During manufacture, a number of optical dies can be attached on the glass substrate using self-alignment of AuSn solder bumps using gaseous flux at about 300 deg C. The glass carrier can be mounted to the silicon carrier to form an optical device carrier assembly comprising micromechanical guide holes to facilitate a optical fiber connection, using self-alignment of SnAg solder bumps using gaseous flux at about 250 deg C. Each individual optical device can be tested at a wafer scale. The resulting optical device assembly can be diced to form individual optical devices having a carrier assembly that exhibits the traits of both a silicon carrier and a glass carrier.
1. An optical device, comprising:
a glass substrate;
an optical die soldered to the glass substrate to form a die-on-glass assembly;
first solder bumps on the glass substrate to facilitate self-alignment by surface tension of the optical die to the glass substrate;
a silicon substrate soldered to the die-on-glass assembly;
a recess in the silicon substrate for receiving the optical die when the silicon substrate is soldered to the die-on-glass assembly;
second solder bumps on the glass substrate to facilitate self-alignment of the silicon substrate to the die-on-glass assembly such that the optical die is accurately positioned within the recess; and
a micromechanical structure on the silicon substrate to permit connection of the optical device to an external component;
whereby the optical device exhibits both optical transparency through the glass substrate and micromechanical structuring from the silicon substrate.
2. The optical device of claim 1 , wherein the first solder bumps on the glass substrate to facilitate self-alignment by surface tension of the optical die to the glass substrate are AuSn solder bumps.
3. The optical device of claim 1 , wherein the second solder bumps on the glass substrate to facilitate self alignment of the silicon substrate to the die-on-glass assembly are AgSn solder bumps.
4. The optical device of claim 1 , and further comprising a thermal conductivity polymer in any gap between the optical die and the recess to assist in heat transfer to the silicon substrate.
5. The optical device of claim 4 , wherein the polymer uses capillary force to assist the heat transfer.
6. The optical device of claim 5 , wherein the polymer is in the recess.
7. The optical device of claim 1 , and further comprising transparent underfill to secure an optical path between the optical die and the glass substrate.
8. The optical device of claim 1 , wherein the micromechanical structure includes guide holes in the silicon substrate.
9. The optical device of claim 1 , wherein the external component is a printed circuit board.