System and method for bonding semiconductor devices

A method, comprising:

• positioning a first semiconductor device over a second semiconductor device, wherein the first semiconductor device comprises a first alignment feature and the second semiconductor device comprises a second alignment feature;
• measuring a location of the second alignment feature;
• forming a third alignment feature on the second semiconductor device, wherein a location of the third alignment feature is based on the location of the second alignment feature;
• measuring a location of the first alignment feature;
• forming a fourth alignment feature on the first semiconductor device, wherein a location of the fourth alignment feature is based on the location of the first alignment feature;
• repositioning the first semiconductor device and the second semiconductor device, wherein the repositioning is based on the relative locations of the third alignment feature and the fourth alignment feature;
• and
• bonding the first semiconductor device to the second semiconductor device.

A method comprising:

• placing a first wafer in a lower wafer holder;
• placing a second wafer in an upper wafer holder;
• detecting, using an upper microscope, an alignment mark on a front side of the first wafer;
• detecting, using the upper microscope, an alignment mark on a back side of the second wafer;
• detecting, using a lower microscope, an alignment mark on a front side of the second wafer;
• and
• detecting, using the lower microscope, an alignment mark on a back side of the first wafer.