Patent ID: 8851133

Claim:
An apparatus, comprising: a non-conductive wafer chuck having first and second holes that extend therethrough, the wafer chuck being configured to hold a wafer; and a pressure control structure that can independently and selectively vary a fluid pressure in each of the first and second holes in a manner such that one of the first and second holes has a pressure below an ambient pressure while the other one of the first and second holes has a pressure above the ambient pressure, wherein the pressure control structure includes: controller that is configured to selectively open and close each of the valves; a vacuum source that is directly connected to each of the first and second holes through respective valves; and a pressure source that is directly connected to each of the first and second holes through respective valves; wherein the second hole is located closer to a center of the wafer chuck than the first hole, and wherein the pressure control structure is configured to facilitate a wave-bonding of the wafer with an external wafer by: creating a vacuum in the first and second holes at a first point in time; supplying a pressurized fluid to the second hole while maintaining the vacuum in the first hole at a second point in time after the first point in time in a manner such that a first portion of the wafer disposed above the second hole is bent above and away from the wafer chuck; and supplying the pressurized fluid to the first and second holes at a third point in time after the second point in time in a manner such that a second portion of the wafer disposed above the first and second holes is bent above and away from the wafer chuck.