A method includes depositing a first dielectric layer on a first substrate of a first device die, etching the first dielectric layer to form a trench, depositing a metallic material in the trench and on a top surface of the first dielectric layer, and performing a chemical mechanical polish (CMP) process to remove a portion of the metallic material from the top surface of the first dielectric layer to form a first metal pad. After the performing of the CMP process, the method selectively etches the first metal pad to form recesses at an edge portion of the first metal pad, deposits a second dielectric layer on a second substrate of a second device die, forms a second metal pad in the second dielectric layer, and bonds the second device die to the first device die.

Disclosed is a method for preparing a display substrate, including: providing a driving substrate; wherein the driving substrate includes: a base substrate; a pixel driving circuit layer; a first pad and a second pad, spaced from each other, and connected to the pixel driving circuit layer; and an electrostatic protection alignment, spaced from the first pad; and transferring a light-emitting element to the driving substrate, such that an anode of the light-emitting element is connected in alignment with the first pad and a cathode of the light emitting-element is connected in alignment with the second pad. The first pad includes a first toothed tip arranged on a side of the first pad facing the electrostatic protection alignment, and the electrostatic protection alignment includes a second toothed tip arranged on a side of the electrostatic protection alignment facing the first pad.