The described embodiments of forming bonding structures for package on package involves removing a portion of connectors and molding compound of the lower package. The described bonding mechanisms enable easier placement and alignment of connectors of an upper package to with connector of a lower package. As a result, the process window of the bonding process is wider. In addition, the bonding structures have smoother join profile and planar joint plane. As a result, the bonding structures are less likely to crack and also are less likely to crack. Both the yield and the form factor of the package on package structure are improved.