Method of fabricating reliable laminate flip-chip assembly
AssigneeAdvanced Micro Devices, Inc.
InventorsRaj N. Master, Edward S. Alcid, Diong-Hing Ding
Life of this patent
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Abstract
A method of fabricating laminate assemblies determines the ideal weight (W) of underfill to be dispensed, based on the size of the semiconductor die and the gap between the die and the laminate substrate. Underfill is dispensed in a single step in an amount between 1.1W and 1.3W to form fillets that cover at least 15% of the height of the semiconductor die on all four sides of the die. The amount of underfill ensures that the fillet coverage imbalance is 30% or less for each of the pairs of opposing sides of the die, thereby improving solder joint reliability.
Claims8
A method of forming a reliable laminate flip-chip assembly having a die and a package, comprising the steps of:
- attaching the die to the package, a gap being formed between the die and the package, the gap having a volume;
- determining ideal weight (W) of the underfill based on the volume;
- and
- dispensing underfill at one side of the die, the weight of underfill dispensed being between 1.10W to 1.30W.
A method of forming a package assembly, comprising the steps of:
- attaching a semiconductor die to a package with a gap formed therebetween;
- and
- dispensing underfill in a single step at a side of the semiconductor die to fill the gap and form fillets;
- wherein the semiconductor die has two pairs of opposing sides with height H, the fillets covering at least 0.15H of each of the sides, and wherein fillet coverage imbalance for the opposing sides of the respective pairs is less than 30%;
- and
- wherein the step of dispensing includes dispensing between 1.10W to 1.30W of underfill, where W is an ideal weight of the underfill.
Dependencies are inferred from the claim text.