Upper and lower wafers can be heated independently to different temperatures and with different ramp rates. The differential temperature can be as high as 350°C (depending on options). This feature can be useful for processes where one wafer needs outgassing while the other one has to stay cold or for activating the getter on one wafer.
Thick wafer bonding and multi stack wafer bonding is possible, accommodating up to 30mm thick stacks.
Various chemistries can be introduced into the chamber using either vapour injection system (DI water or acid) or pressure control system (gas). Wafers held in separation can be treated just before contact, for example for Copper oxide removal.
Large wafer separation allows more effective evacuation of the space between the wafers. All surfaces of cavities can be efficiently outgassed while the wafers are heated. It is particularly important for vacuum or gas encapsulation.
