Field-assisted fusion bonding
View Patent ↗A method of field-assisted fusion bonding produces multiple-layer devices. Contacts ( 301, 303, 305, 307, 309 ) are placed at various points along different surfaces of a combination of two or more wafers ( 201, 203, 205, 501, 503, 505, 801, 803 ). An electric field is applied to the contacts ( 301, 303, 305, 307, 309 ), thereby creating an electrostatic attractive force between the wafers ( 201, 203, 205, 501, 503, 505, 801, 803 ). The temperature of the wafer combination is elevated to a fusion bonding temperature while the electric field is applied.
1. An apparatus, comprising:
a first wafer having a hydrolyzed first surface;
a second wafer aligned with such that the hydrolyzed first surface of the first wafer and a first surface of the second wafer are touching;
a heater to elevate the first wafer and the second wafer to a fusion bonding temperature; and
an electric field device for applying an electric field to the wafers to create an attractive force between the wafers.
2. The apparatus of claim 1 wherein the electrical field device applies a voltage between at least one electrical contact on a second surface of the first wafer and at least one electrical contact on a second surface of the second wafer.
3. The apparatus of claim 2 , further comprising:
an oxide layer grown on at least one of the hydrolyzed first surface of the first wafer and the first surface of the second wafer.
4. The apparatus of claim 3 , wherein the oxide layer comprises a discontinuous oxide that forms a framework of oxide and matched the framework of each oxide layer.
5. The apparatus of claim 3 further comprising:
a third wafer having a hydrolyzed first surface and a second surface disposed between the hydrolyzed first surface of the first wafer, and
wherein the hydrolyzed first surface of the second wafer, and the first wafer, the second wafer and the third wafer are aligned such that the hydrolyzed first surface of the first wafer and the hydrolyzed surface of the third wafer are touching and the hydrolyzed first surface of the second wafer and the hydrolyzed second surface of the third wafer are touching.
6. The apparatus of claim 5 , further comprising:
an oxide layer grown on at least one of the first surface of the third wafer and the second surface of the third wafer.
7. The apparatus of claim 6 , any oxide layer comprises a discontinuous oxide that forms a frame work matching the framework of each oxide layer.
8. The apparatus of claim 6 , wherein the first wafer and the second wafer are silicon-on-insulator wafers.
9. The apparatus of claim 6 , wherein the first wafer and the second wafer are glass wafers and the third wafer is a silicon wafer.
10. The apparatus of claim 6 , wherein the wafers are annealed.