Direct bond method providing thermal expansion matched devices
A method of transferring an integrated circuit (IC) onto an alternative substrate is provided at a wafer level to enable coefficient of thermal expansion (CTE) matching for a circuit layer to a different material. The method is executable relative to a wafer with a circuit layer, a first major surface, a second major surface opposite the first major surface, and a substrate affixed to the first major surface. The method includes temporarily bonding a handle to the second major surface, removing a majority of the substrate to expose the first major surface and bonding a second substrate to the first major surface with deposited bonding material.
1. A method of transferring an integrated circuit (IC) onto an alternative substrate at a wafer level to enable coefficient of thermal expansion (CTE) matching for a circuit layer to a different material,
the method being executable relative to a wafer with a circuit layer, a first major surface, a second major surface opposite the first major surface, and a substrate affixed to the first major surface,
the method comprising:
temporarily bonding a handle to the second major surface;
removing a substantial portion of the substrate to expose the first major surface;
bonding a second substrate to the first major surface with deposited bonding material to hybridize the circuit layer;
removing the handle from the second major surface; and
connecting the second major surface to an additional substrate, which is thermally matched to the circuit layer hybridized with the second substrate.
2. The method according to claim 1 , wherein the wafer comprises a complementary-metal-oxide-semiconductor (CMOS) wafer.
3. The method according to claim 1 , wherein temporarily bonding a handle to the second major surface comprises applying thermoplastic adhesive.
4. The method according to claim 1 , wherein the removing of the substantial portion of the substrate comprises at least one or more of grinding and polishing.
5. The method according to claim 1 , wherein the removing of the substantial portion of the substrate leaves a remainder of the substrate that is thinner than the circuit layer.
6. The method according to claim 1 , wherein the circuit layer is approximately 10 μm thick and the removing of the substantial portion of the substrate leaves a remainder of the substrate that is thinner than the circuit layer.
7. The method according to claim 1 , wherein the deposited bonding material comprises bonding oxide.
8. The method according to claim 1 , wherein bonding a second substrate to the first major surface comprises:
depositing the bonding material to the first major surface with a thickness of approximately 2-15 nm; and
polishing the bonding material down to a thickness of approximately 0.3-0.5 nm.
9. The method according to claim 1 , wherein the second substrate comprises a plasma activated surface or aluminum oxide.
10. The method according to claim 1 , wherein the circuit layer is approximately 10 μm thick and the second substrate is approximately 1500 μm thick.
11. The method according to claim 1 , wherein the additional substrate comprises a detector array.
12. The method according to claim 11 , wherein:
the detector array comprises photoelectric elements and an additional surface which is complementary to the second major surface, and
the connecting comprises depositing interconnects on the second major surface and on the additional surface.
13. A method of transferring an integrated circuit (IC) onto an alternative substrate at a wafer level to enable coefficient of thermal expansion (CTE) matching,
the method being executable relative to a complementary-metal-oxide-semiconductor (CMOS) wafer with a circuit layer, a first major surface, a second major surface opposite the first major surface and a substrate affixed to the first major surface;
temporarily bonding a handle to the second major surface;
removing a substantial portion of the substrate to expose the first major surface through a thin layer of substrate remainder; and
bonding a Sapphire substrate to the first major surface and the thin layer of substrate remainder with a deposited and polished bonding oxide to hybridize the circuit layer;
removing the handle from the second major surface; and
connecting the second major surface to an additional substrate, which is thermally matched to the circuit layer hybridized with the Sapphire substrate.
14. The method according to claim 13 , wherein:
temporarily bonding a handle to the second major surface comprises applying thermoplastic adhesive.
15. The method according to claim 13 , wherein the removing of the substantial portion of the substrate comprises at least one or more of grinding and polishing the substrate down to the substrate remainder.
16. The method according to claim 13 , wherein the circuit layer is approximately 10 μm thick and the substrate remainder is thinner than the circuit layer.
17. The method according to claim 13 , wherein the circuit layer is approximately 10 μm thick and the Sapphire substrate is approximately 1500 μm thick.
18. The method according to claim 13 , wherein the additional substrate comprises a detector array.
19. The method according to claim 18 , wherein:
the detector array comprises photoelectric elements and an additional surface which is complementary to the second major surface, and
the connecting comprises depositing interconnects on the second major surface and on the additional surface.