Semiconductor Package Under-fill Fillet Molding Resin Coverage
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Solution Overview
Problem
As semiconductor devices shrink in size and thickness, existing non-conductive film (NCF) under-fill technologies face challenges in reducing exterior defects and enhancing product reliability, particularly due to issues with moisture infiltration and electrical migration.
Innovation Solution
A semiconductor package design featuring a substrate with stacked semiconductor devices, an under-fill fillet on their side surfaces, and a molding resin that completely covers the uppermost end of the fillet, ensuring a planar surface coplanar with the semiconductor device periphery, thereby preventing moisture infiltration and exterior defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the semiconductor device size and thickness are reduced, then the device integration density is improved, but exterior defects and reliability issues increase due to moisture infiltration and electrical migration
Solution Approach 1:
The under-fill fillet is formed in advance before the molding resin is applied, creating a protective barrier structure that prevents moisture infiltration and electrical migration from occurring during subsequent processing and operation. This preliminary protective structure addresses reliability concerns before they can manifest in the miniaturized device
Solution Approach 2:
The under-fill fillet acts as an intermediary material between the semiconductor device and the external environment, providing a protective barrier that prevents direct contact between moisture/electrical contaminants and the device structure. This intermediary layer resolves the reliability issue while maintaining the reduced device dimensions
2Ease of manufacture
If the under-fill fillet upper end is left protruding, then the manufacturing process is simpler, but exterior defects occur due to exposed fillet surfaces
Solution Approach 1:
The molding resin is applied to completely cover the under-fill fillet, merging the fillet structure with the molded package body. This integration eliminates the protruding fillet surface that causes exterior defects while maintaining the protective function of the under-fill material within the unified package structure
Solution Approach 2:
The solution addresses the exterior defect issue by transitioning from a two-dimensional surface consideration to a three-dimensional encapsulation approach. The molding resin covers the fillet in the vertical dimension, eliminating exposed surfaces that would otherwise create exterior defects
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces exterior defects and enhances product reliability by ensuring the under-fill fillet is fully covered by the molding resin, preventing moisture ingress and maintaining the integrity of the semiconductor package.
Implementation Method 1
heating the NCF so that a portion of the NCF protrudes from side surfaces of the plurality of semiconductor devices and at least partially covers the side surfaces thereof to form a preliminary under-fill fillet
Data Source
AI summary
A semiconductor package includes a substrate, a plurality of semiconductor devices stacked on the substrate, an under-fill fillet on side surfaces of the plurality of semiconductor devices, and a molding resin surrounding the plurality of semiconductor devices. An uppermost end of the under-fill fillet includes a planar surface coplanar with an upper surface of a periphery of an uppermost semiconductor device among the plurality of semiconductor devices, and the molding resin completely covers the planar surface.