Patent ID: 9412629
Filing Date: 2016-08-09
CPC Classification: H01L

Claim Text:
1. An apparatus to bond a first wafer to a second wafer, the apparatus comprising: a first pressure application device configured to apply pressure at a central region of the first wafer in a direction toward the second wafer to initiate a bonding process between the first wafer and the second wafer; one or more second pressure application devices configured to apply pressure between the central region and an outer edge of the first wafer to complete the bonding process, wherein the one or more second pressure application devices apply pressure on the first wafer in the direction toward the second wafer after the first pressure application device has initiated the bonding process and while the first pressure application device continues to apply pressure at the central region, wherein the first pressure application device includes a pin and the second pressure application devices include a set of pins arranged to encircle the pin at a first radial distance from the pin, wherein the set of pins is arranged to begin applying pressure on the first wafer simultaneously, and each of the set of pins is arranged to move radially outward to a second radial distance from the pin, and wherein the set of pins is arranged to continue to apply pressure on the first wafer while moving from the first radial distance to the second radial distance; and a controller configured to control an amount of pressure applied by the first pressure application device and the one or more second pressure application devices on the first wafer in the direction toward the second wafer.