Hybrid bonding systems and methods for semiconductor wafers
Hybrid bonding systems and methods for semiconductor wafers are disclosed. In one embodiment, a hybrid bonding system for semiconductor wafers includes a chamber and a plurality of sub-chambers disposed within the chamber. A robotics handler is disposed within the chamber that is adapted to move a plurality of semiconductor wafers within the chamber between the plurality of sub-chambers. The plurality of sub-chambers includes a first sub-chamber adapted to remove a protection layer from the plurality of semiconductor wafers, and a second sub-chamber adapted to activate top surfaces of the plurality of semiconductor wafers prior to hybrid bonding the plurality of semiconductor wafers together. The plurality of sub-chambers also includes a third sub-chamber adapted to align the plurality of semiconductor wafers and hybrid bond the plurality of semiconductor wafers together.
1. A method comprising:
forming a first protection layer over at least a first contact pad of a first semiconductor wafer;
forming a second protection layer over at least a second contact pad of a second semiconductor wafer;
placing the first semiconductor wafer and the second semiconductor wafer in a first environment after forming the first protection layer and the second protection layer;
removing the first protection layer and the second protection layer while the first semiconductor wafer and the second semiconductor wafer are in a reduced oxygen environment, wherein an amount of oxygen in the reduced oxygen environment is lower than an amount of oxygen in the first environment;
coupling a top surface of the second semiconductor wafer to a top surface of the first semiconductor wafer while the first semiconductor wafer and the second semiconductor wafer are in the reduced oxygen environment; and
bonding the first semiconductor wafer to the second semiconductor wafer while the first semiconductor wafer and the second semiconductor wafer are in the reduced oxygen environment.
2. The method of claim 1 , further comprising after removing the first protection layer and the second protection layer, activating the top surfaces of the first semiconductor wafer and the second semiconductor wafer while the first semiconductor wafer and the second semiconductor wafer are in the reduced oxygen environment.
3. The method of claim 1 , wherein the first semiconductor wafer and the second semiconductor wafer are not removed from the reduced oxygen environment after removing the first protective layer and the second protective layer until after bonding the first semiconductor wafer to the second semiconductor wafer.
4. The method of claim 1 , wherein coupling the top surface of the second semiconductor wafer to the top surface of the first semiconductor wafer comprises aligning a first conductive pad at the top surface of the first semiconductor wafer to a second conductive pad at the top surface of the second semiconductor wafer.
5. The method of claim 4 , wherein removing the first protection layer and the second protection layer comprises removing copper oxide at top surfaces of the first conductive pad and the second conductive pad.
6. The method according to claim 1 , wherein forming the first protection layer and the second protection layer comprises forming a material selected from the group consisting essentially of C, Si, H, and combinations thereof.
7. The method according to claim 1 , wherein removing the first protection layer and the second protection layer comprises a method selected from the group consisting essentially of exposure to an acid, exposure to HCOOH, exposure to HCl, thermal decomposition, thermal desorption, exposure to a plasma removal treatment, exposure to ultraviolet (UV) light, and combinations thereof.
8. A method comprising:
providing a first semiconductor wafer comprising a first plurality of conductive pads in a first insulating material on a top surface of the first plurality of conductive pads;
providing a second semiconductor wafer comprising a second plurality of conductive pads in a second insulating material on a top surface of the second plurality of conductive pads;
forming a first protection layer and a second protective layer on the first plurality of conductive pads and the second plurality of conductive pads, respectively, wherein the first protective layer and the second protective layer reduces oxidation of the first plurality of conductive pads and the second plurality of conductive pads;
removing the first protective layer and the second protection layer to expose the first plurality of conductive pads and the second plurality of conductive pads;
activating the top surfaces of the first semiconductor wafer and the second semiconductor wafer; and
bonding the first semiconductor wafer to the second semiconductor wafer, wherein bonding the first semiconductor wafer to the second semiconductor wafer comprises:
forming a dielectric-to-dielectric bond between the first insulating material and the second insulating material; and
forming a metal-to-metal bond between the first plurality of conductive pads and the second plurality of conductive pads.
9. The method of claim 8 further comprising before removing the first protection layer and the second protection layer, placing the first semiconductor wafer and the second semiconductor wafer in a reduced oxygen environment, wherein an oxygen amount in the reduced oxygen environment is lower than an oxygen amount of an environment in which the first semiconductor wafer and second semiconductor wafer were stored prior to removing the first protection layer and the second protection layer, and wherein the first semiconductor wafer and the second semiconductor wafer are not removed from the reduced oxygen environment until after hybrid bonding the first semiconductor wafer to the second semiconductor wafer.
10. The method of claim 8 further comprising cleaning the top surfaces of the first semiconductor wafer and the second semiconductor wafer.
11. The method of claim 8 , wherein the top surfaces of the first semiconductor wafer and the second semiconductor wafer include an oxide material formed thereon, and wherein removing the first protection layer and the second protection layer or activating the top surfaces comprises removing a portion of the oxide material.
12. The method of claim 11 , wherein the first plurality of conductive pads and the second plurality of conductive pads comprises copper, and wherein removing the portion of the oxide material comprises removing copper oxide.
13. The method of claim 8 , further comprising between forming the first protection layer and the second protection layer and bonding the first semiconductor wafer to the second semiconductor wafer, storing the first semiconductor wafer and the second semiconductor wafer for a storage time of greater than about one day.
14. The method of claim 8 , wherein the first protection layer and the second protection layer comprises an insulating material comprising C, Si, H, or a combination thereof.
15. A method comprising:
forming a first protection layer over a first top surface of a first semiconductor wafer, the first semiconductor wafer comprising a first conductive pad disposed in a first insulating material at the first top surface;
placing the first semiconductor wafer and a second semiconductor wafer into a reduced oxygen environment, wherein the second semiconductor wafer comprises a second conductive pad disposed in a second insulating material at a second top surface of the second semiconductor wafer;
removing the first protection layer from over the first top surface of the first semiconductor wafer;
removing a conductive oxide at a top surface of the first conductive pad; and
bonding the first semiconductor wafer to the second semiconductor wafer, wherein removing the first protection layer, removing the conductive oxide at the first top surface to the second top surface, and bonding the first semiconductor wafer to the second semiconductor wafer are performed without removing the first semiconductor wafer and the second semiconductor wafer from the reduced oxygen environment, and wherein bonding the first semiconductor wafer to the second semiconductor wafer comprises:
forming a bonding interface between the first conductive pad and the second conductive pad; and
forming a bonding interface between the first insulating material and the second insulating material.
16. The method of claim 15 , wherein removing the first protection layer and removing the conductive oxide are performed in a same process.
17. The method according to claim 15 further comprising:
activating the first top surface and the second top surface; and
cleaning the first top surface and the top surface, wherein activating and cleaning the first top surface and the second top surface are performed without removing the first semiconductor wafer and the second semiconductor wafer from the reduced oxygen environment.
18. The method of claim 17 , wherein activating the first top surface removes the conductive oxide.
19. The method according to claim 15 , further comprising:
before placing the second semiconductor wafer into the reduced oxygen environment, forming a second protection layer over the second top surface; and
after placing the second semiconductor wafer into the reduced oxygen environment, removing the second protection layer.
20. The method according to claim 15 , wherein removing the first protection layer comprises a method selected from the group consisting essentially of exposure to an acid, exposure to HCOOH, exposure to HCl, thermal decomposition, thermal desorption, exposure to a plasma removal treatment, exposure to ultraviolet (UV) light, and combinations thereof.