Cu—Cu direct welding for packaging application in semiconductor industry
Disclosed is a method of bonding two copper structures involving compressing a first copper structure with a second copper structure under a stress from 0.1 MPa to 50 MPa and under a temperature of 250° C. or less so that a bonding surface of the first copper structure is bonded to the bonding surface of the second copper structure. At least one of the bonding surface of the first copper structure and the bonding surface of the second copper structure have a layer of nanograins of copper having an average grain size of 5 nm to 500 nm. The layer of the nanograins of copper having a thickness of 10 nm to 10 μm.
1 . A method of directly bonding two copper structures, comprising: compressing a first copper structure with a second copper structure under a stress from 1 MPa to 20 MPa and under a temperature from 100° C. to 250° C. so that a bonding surface of the first copper structure is bonded to a bonding surface of the second copper structure;
at least one of the bonding surface of the first copper structure and the bonding surface of the second copper structure has a layer of nanograins consisting of copper having an average grain size of 5 nm to 500 nm, and chemical additives of copper electrodeposition electrolyte, the layer of the nanograins of copper having a thickness of 10 nm to 10 μm.
2 . The method according to claim 1 , wherein both the bonding surface of the first copper structure and the bonding surface of the second copper structure have a layer of nanograins of copper having an average grain size of 5 nm to 500 nm, the layer of the nanograins of copper having a thickness of 10 nm to 10 μm.
3 . The method according to claim 1 , wherein the nanograins of copper have an average grain size of 10 nm to 250 nm.
4 . The method according to claim 2 , wherein the nanograins of copper have an average grain size of 10 nm to 250 nm.
5 . The method according to claim 1 , wherein the nanograins of copper have an average grain size of 10 nm to 250 nm.
6 . The method according to claim 2 , wherein the nanograins of copper have an average grain size of 15 nm to 100 nm.
7 . The method according to claim 1 , wherein the first copper structure and the second copper structure are compressed under a temperature from 120° C. to 200° C.
8 . The method according to claim 1 , wherein the first copper structure and the second copper structure are compressed for a time from 0.5 to 60 minutes.
9 . The method according to claim 1 , with the proviso that a CMP process associated with the method of bonding two copper structures is not conducted.
10 . A method of directly bonding two copper structures within a 5G wireless chipset, comprising: compressing a first copper structure within a wireless chipset with a second copper structure within a wireless chipset under a stress from 1 MPa to 20 MPa and under a temperature from 100° C. to 250° C. so that a bonding surface of the first copper structure is bonded to a bonding surface of the second copper structure;
at least one of the bonding surface of the first copper structure and the bonding surface of the second copper structure has a layer of nanograins consisting of copper having an average grain size of 5 nm to 500 nm, and chemical additives of copper electrodeposition electrolyte, the layer of the nanograins of copper having a thickness of 10 nm to 10 μm.
11 . The method according to claim 10 , wherein both the bonding surface of the first copper structure and the bonding surface of the second copper structure have a layer of nanograins of copper having an average grain size of 5 nm to 500 nm, the layer of the nanograins of copper having a thickness of 10 nm to 10 μm.
12 . The method according to claim 10 , wherein the nanograins of copper have an average grain size of 10 nm to 250 nm.
13 . The method according to claim 11 , wherein the nanograins of copper have an average grain size of 10 nm to 250 nm.
14 . The method according to claim 10 , wherein the nanograins of copper have an average grain size of 10 nm to 250 nm.
15 . The method according to claim 11 , wherein the nanograins of copper have an average grain size of 15 nm to 100 nm.
16 . The method according to claim 10 , wherein the first copper structure and the second copper structure are compressed under a temperature from 120° C. to 200° C.
17 . The method according to claim 10 , wherein the first copper structure and the second copper structure are compressed for a time from 0.5 to 60 minutes.
18 . The method according to claim 10 , with the proviso that a CMP process associated with the method of bonding two copper structures is not conducted.
19 . The method according to claim 1 , wherein the layer of nanograins of copper has a thickness of 25 nm to 5 μm.
20 . The method according to claim 1 , wherein the layer of nanograins of copper have a thickness of 50 nm to 1 μm.