Die corner removal for molding compound crack suppression in semiconductor die packaging and methods for forming the same

A chip package structure, comprising:

• at least one semiconductor die attached to a redistribution structure;
• a first underfill material portion laterally surrounding a portion of the at least one semiconductor die;
• a molding compound laterally surrounding at least one semiconductor die;
• a package substrate attached to the redistribution structure;
• and
• a second underfill material portion comprising:
• an inter-substrate underfill portion laterally surrounding the redistribution structure and located within an outer periphery of the molding compound in a plan view, and
• a peripheral material portion located outside the outer periphery of the molding compound in the plan view and comprising at least one cut region having an L-shaped vertical cross-sectional shape, wherein each of the at least one cut region has a vertically-extending portion having a uniform lateral width and a horizontally-extending portion wherein:
• the molding compound has a rectangular outer periphery in the plan view;
• and
• the at least one cut region comprises four cut regions located outside, and in proximity to, four corners of the rectangular outer periphery.

A method of forming a chip package structure, comprising:

• providing a redistribution structure;
• attaching at least one semiconductor die to the redistribution structure;
• forming a first underfill material portion between the redistribution structure and the at least one semiconductor die;
• attaching a package substrate to the redistribution structure;
• forming a second underfill material portion between the redistribution structure and the package substrate and around the redistribution structure;
• and
• forming at least one cut region in the second underfill material portion by cutting portions of the second underfill material portion,
• wherein the portions of the second underfill material portion are cut by performing a processing step selected from a first processing step or a second processing step,
• the first processing step comprising irradiating a laser beam to each of the cut regions of the second underfill material portion, whereby a material of the second underfill material portion is ablated by laser irradiation by the laser beam, and
• the second processing step comprising milling the portions of the second underfill material portion using a milling apparatus, whereby a material of the second underfill material portion is milled by the milling apparatus.