Semiconductor Package Underfill Layout for Die Shift Prevention
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Solution Overview
Problem
Existing semiconductor packaging technologies face challenges with die dislocation during the molding process, leading to reduced yields due to undesirable movement of semiconductor dies under molding pressure, which affects the alignment of subsequent materials in the redistribution layer (RDL).
Innovation Solution
The use of an underfill material surrounding the semiconductor dies before encapsulation helps prevent die movement by securing them in place, ensuring proper alignment of subsequent layers and improving packaging reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molding material is formed to cover semiconductor dies, then encapsulation is achieved, but die dislocation occurs due to molding pressure
Solution Approach 1:
The underfill material is applied to the semiconductor dies before the encapsulation process. This preliminary action secures the dies in their proper positions, preventing dislocation when molding pressure is subsequently applied during encapsulation.
Solution Approach 2:
The underfill material acts as an intermediary substance between the semiconductor dies and the molding material. It provides mechanical support and positioning for the dies, mediating the effect of molding pressure to prevent die displacement while still allowing complete encapsulation.
2Ease of manufacture
If molding pressure is applied to cover dies, then encapsulation is completed, but die movement causes misalignment of subsequent materials
Solution Approach 1:
The underfill material is applied in advance to secure dies before encapsulation. This preliminary positioning action ensures that when molding pressure is applied for easy encapsulation, the dies remain properly aligned for subsequent RDL material deposition.
Solution Approach 2:
The underfill material provides a cushioning effect beforehand, absorbing and distributing the molding pressure uniformly. This prevents localized stress concentrations that would cause die movement and subsequent misalignment of RDL materials.
3Productivity
If semiconductor dies are positioned on carrier, then wafer level packaging is enabled, but die dislocation reduces manufacturing yield
Solution Approach 1:
The underfill material is applied to each die on the wafer before encapsulation. This preliminary action maintains die positions throughout the high-productivity wafer-level packaging process, preventing dislocation and ensuring high manufacturing yield.
Solution Approach 2:
The underfill material provides self-positioning and self-support for the semiconductor dies during the packaging process. Each die is independently secured by its own underfill, enabling wafer-level processing while maintaining individual die alignment and maximizing yield.
Data Source
AI summary
A semiconductor package includes a chiplet, a first underfill surrounding the chiplet, and a first encapsulant laterally covering the first underfill. The chiplet includes a semiconductor substrate and die connectors disposed over the semiconductor substrate. The first underfill includes first fillers, and a portion of the first fillers has a substantially planar surface at a first surface of the first underfill. The first encapsulant includes a first surface and a second surface opposite to the first surface, the first surface is substantially leveled with surfaces of the die connectors, and the second surface is substantially leveled with the first surface of the first underfill.