Dual-Viscosity Non-Conductive Layers for Void-Free Chip Packaging
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Solution Overview
Problem
Traditional semiconductor package structures suffer from voids and solder bridges due to air trapped in the opening region during the thermal compress bonding process, leading to quality issues.
Innovation Solution
A package structure with two non-conductive layers of differing melt viscosities is employed, where the layer with higher viscosity covers the chip and the layer with lower viscosity fills the opening without voids, ensuring a void-free bond and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single non-conductive film layer is used in traditional package structures, then the structure is simple and easy to manufacture, but air remains trapped in the opening region causing voids and holes that lead to solder bridge quality problems
Solution Approach 1:
The single non-conductive film layer is segmented into two distinct layers: a first non-conductive film layer and a second non-conductive film layer. This segmentation allows each layer to perform different functions - the first layer provides structural support while the second layer with lower viscosity ensures complete filling of the opening region without trapping air, thereby eliminating voids and preventing solder bridge defects.
Solution Approach 2:
The patent employs a composite structure consisting of two non-conductive film layers with different material properties. The first layer has higher viscosity for structural stability, while the second layer has lower viscosity for optimal flow and void-free filling. This composite approach combines the advantages of both material characteristics to achieve reliable solder bridges without increasing overall manufacturing complexity.
2Manufacturing precision
If the non-conductive film layer is filled in the opening region during thermal compress bonding, then bonding is achieved, but air stays in the opening region causing holes and quality problems
Solution Approach 1:
The patent changes the viscosity parameter of the non-conductive film material by using two different layers. The second layer specifically has lower viscosity to enable complete filling of the opening region during thermal compress bonding. This parameter change ensures that the material flows sufficiently to displace and eliminate trapped air, achieving void-free filling without compromising bonding quality.
Solution Approach 2:
Different regions of the non-conductive film structure are assigned different material qualities. The first layer maintains higher viscosity for structural integrity, while the second layer has lower viscosity specifically in the opening region to ensure complete filling. This local differentiation of material properties allows the structure to simultaneously maintain stability and achieve complete filling without air entrapment.
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 prevents voids and solder bridges, enhancing the quality and reliability of the semiconductor package by controlling the flow of the lower viscosity layer and suppressing overflow.
Implementation Method 1
a melt viscosity of the first non-conductive layer is greater than a melt viscosity of the second non-conductive layer
Data Source
AI summary
Embodiments disclose a package structure and a fabricating method. The package structure includes: a semiconductor chip; a first non-conductive layer covering a front surface of the semiconductor chip and part of a side wall of the semiconductor chip; a second non-conductive layer positioned on an upper surface of the first non-conductive layer and covering at least part of a side wall of the first non-conductive layer, wherein a melt viscosity of the first non-conductive layer is greater than a melt viscosity of the second non-conductive layer; a substrate; and a solder mask layer positioned on a surface of the substrate, where a first opening is provided in the solder mask layer. The semiconductor chip is flip-chip bonded on the substrate, a surface of the second non-conductive layer away from the first non-conductive layer and a surface of the solder mask layer away from the substrate are bonding surfaces.