Stacked package structure and method for forming the same

A method for forming a stacked package structure, comprising:

• providing a first substrate comprising an upper surface and a lower surface opposite to the upper surface;
• forming a chip stacked structure on the upper surface of the first substrate, wherein the chip stacked structure comprises a plurality of first semiconductor chips stacked in sequence along a direction perpendicular to the upper surface of the first substrate, and the chip stacked structure is electrically connected to the first substrate;
• providing a first flexible circuit board comprising a first functional surface and a second functional surface opposite to the first functional surface, wherein the first flexible circuit board comprises a first portion and at least one second portion connected to the first portion, the first functional surface of the first portion of the first flexible circuit board is mounted on a top surface of the chip stacked structure and is electrically connected to the chip stacked structure, and the second portion of the first flexible circuit board is bent to a side surface of the chip stacked structure;
• providing a second flexible circuit board comprising a third functional surface and a fourth functional surface opposite to the third functional surface, wherein a part of the third functional surface of the second flexible circuit board is mounted on the second functional surface of the second portion of the first flexible circuit board and is electrically connected to the first flexible circuit board;
• and
• providing second semiconductor chips, wherein the second semiconductor chips are mounted on the fourth functional surface of the second flexible circuit board and are electrically connected to the second flexible circuit board.