Wafer structures and wafer bonding methods
Wafer structures and wafer bonding methods are provided. In some embodiments, a wafer bonding method includes providing a conductive wafer and a plurality of insulating wafers, the conductive wafer being larger than the insulating wafers; performing a pre-treatment operation on the conductive wafer, the insulating wafers, or both; and directly bonding the insulating wafers to the conductive wafer.
1. A wafer bonding method comprising:
providing a conductive wafer and a plurality of insulating wafers, the conductive wafer being larger than the insulating wafers;
performing a plasma treatment operation on the conductive wafer, the insulating wafers, or both; and
directly bonding the insulating wafers to the conductive wafer.
2. The wafer bonding method of claim 1 , further comprising performing or a wet treatment operation on the conductive wafer, the insulating wafers, or both.
3. The wafer bonding method of claim 1 , wherein the performing the plasma treatment operation comprises using at least one of O 2 , NH 3 , SF 6 , Ar, Cl 2 , CHF 3 , and H 2 O.
4. The wafer bonding method of claim 1 , wherein, as a result of the plasma treatment operation, dangling bonds are formed on a bonding surface of the conductive wafer, bonding surfaces of the insulating wafers, or both.
5. The wafer bonding method of claim 4 , wherein the dangling bonds comprise hydrophilic dangling bonds or hydrophobic dangling bonds.
6. The wafer bonding method of claim 1 , wherein the directly bonding the insulating wafers to the conductive wafer comprises laying the insulating wafers over the conductive wafer and either performing a thermal treatment operation on the conductive wafer and the insulating wafers or physically pressing the insulating wafers to the conductive wafer.
7. The wafer bonding method of claim 1 , wherein the bonding surfaces of the conductive wafer and the insulating wafers are all flat.
8. The wafer bonding method of claim 1 , further comprising forming an insulating layer on a bonding surface of the conductive wafer, bonding surfaces of the insulating wafers, or both.
9. The wafer bonding method of claim 1 , further comprising polishing the bonding surface of the conductive wafer, the bonding surfaces of the insulating wafers, or both.
10. The wafer bonding method of claim 1 , further comprising washing the conductive wafer and the insulating wafers before the performing the plasma treatment operation.
11. The wafer bonding method of claim 2 , wherein performing the wet treatment operation comprises using at least one of H 2 SO 4 , HNO 3 , HCl, H 2 O 2 , H 5 IO 6 , Standard Clean-1 (SC-1), and Standard Clean-2 (SC-2).