A method of manufacturing a die stack structure includes the following steps. A first bonding structure is formed over a front side of a first die. The method of forming the first bonding structure includes the following steps. A first bonding dielectric material is formed on a first test pad of the first die. A first blocking layer is formed over the first bonding dielectric material. A second bonding dielectric material and a first dummy metal layer are formed over the first blocking layer. The first dummy metal layer and the first test pad are electrically isolated from each other by the first blocking layer. Thereafter, a second bonding structure is formed over a front side of a second die. The first die and the second die are bonded through the first bonding structure and the second bonding structure.

This invention relates to the process of correcting misalignment and filling voids after a microdevice transfer process. The process involves transfer heads, measurement of offset and misalignment in horizontal, vertical, and rotational errors. An execution of the new offset vector for the next transfer corrects the alignment.