Method of forming a multi-chip stacked structure including a thin interposer chip having a face-to-back bonding with another chip

A method of forming a multi-chip assembly of semiconductor chips comprising:

• forming a stacked substrate assembly by bonding a semiconductor substrate to a temporary substrate through an array of first solder balls that bonds to an array of first solder pads on said semiconductor substrate;
• dicing said stacked substrate assembly to form a plurality of stacked temporary structures, each of said plurality of stacked temporary structures comprising a first semiconductor chip that is a portion of said semiconductor substrate and a handle portion that is a portion of said temporary substrate;
• bonding a second semiconductor chip to a stacked temporary structure among said plurality of stacked temporary structures, wherein an array of second solder balls is bonded to an array of second solder pads located on a first semiconductor chip in said stacked temporary structure and an array of third solder pads located on said second semiconductor chip;
• detaching a handle portion from said stacked temporary structure to form a stacked semiconductor chip structure;
• and
• forming a multi-chip assembly of semiconductor chips by bonding at least one stacked semiconductor chip structure including said stacked semiconductor chip structure to a packaging substrate.