EXTRUSION-RESISTANT SOLDER INTERCONNECT STRUCTURES AND METHODS OF FORMING

摘要

Various embodiments include methods of forming interconnect structures, and the structures formed by such methods. In one embodiment, a method can include: providing a precursor interconnect structure having: a photosensitive polyimide (PSPI) layer; a controlled collapse chip connection (C4) bump overlying the PSPI layer; and a solder overlying the C4 bump and contacting a side of the C4 bump. The method can further include recessing a portion of the PSPI layer adjacent to the C4 bump to form a PSPI pedestal under the C4 bump. The method can additionally include forming an underfill abutting the PSPI pedestal and the C4 bump, wherein the underfill and the solder form an interface separated from the PSPI pedestal.