Rigid Interposer Packaging for Low-Warpage Semiconductor Assembly
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Solution Overview
Problem
Semiconductor device packages face challenges in accommodating sophisticated features that impact reliability, performance, and cost, particularly due to mismatched thermal expansion coefficients and warpage issues.
Innovation Solution
The use of a rigid interposer formed from materials like glass or silicon with matched thermal expansion coefficients, combined with conductive vias and a redistribution layer structure, to create a thin flip-chip fan-out package that minimizes warpage and enhances connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional packaging configurations are used to accommodate sophisticated semiconductor features, then device functionality is achieved, but reliability decreases and warpage increases
Solution Approach 1:
An interposer substrate is introduced as an intermediary component between the semiconductor die and the package substrate. This interposer serves as a mediator that provides a stable, controlled-impedance transmission path for high-speed signals while isolating the semiconductor die from warpage and thermal stress in the conventional packaging structure, thereby maintaining reliability while accommodating sophisticated features.
2Adaptability or versatility
If conventional packaging configurations are used to accommodate sophisticated semiconductor features, then device functionality is achieved, but performance decreases
Solution Approach 1:
The interposer substrate acts as an intermediary that provides controlled-impedance transmission lines for high-speed differential signals, ensuring signal integrity and performance. It enables sophisticated features like high-speed interfaces while maintaining electrical performance through its controlled impedance characteristics and stable signal path.
Solution Approach 2:
The interposer substrate changes the electrical parameters of the package by providing controlled-impedance transmission paths with specific characteristic impedances (e.g., 50 ohms, 100 ohms differential). This parameter control ensures optimal signal transmission performance for sophisticated semiconductor features while isolating the die from performance-degrading effects in the package structure.
3Reliability
If interposer with matched thermal expansion coefficient is used, then warpage is reduced and reliability is improved, but device complexity increases
Solution Approach 1:
The interposer substrate is designed with a coefficient of thermal expansion that matches both the semiconductor die and the package substrate. This homogeneity in thermal expansion properties across all layers prevents differential expansion and contraction during temperature cycling, eliminating warpage and improving reliability without requiring complex compensation mechanisms.
4Adaptability or versatility
If sophisticated semiconductor features are accommodated in conventional packages, then functionality is achieved, but product or system costs increase
Solution Approach 1:
The interposer substrate serves multiple functions simultaneously: it provides controlled-impedance transmission lines for high-speed signals, acts as a stress isolation layer to prevent warpage, provides a stable mounting platform for the semiconductor die, and enables thermal management. This multi-functionality accommodates sophisticated features while avoiding the need for multiple separate components, thereby controlling complexity and cost.
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
This approach results in a semiconductor device with improved reliability, reduced warpage, and cost-effective packaging by aligning thermal expansion properties and enhancing interconnectivity.
Implementation Method 1
The interposer substrate is formed from a rigid material which has a coefficient of thermal expansion substantially matched with that of the semiconductor die
Data Source
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AI summary
A method of forming a semiconductor device is provided. The method includes forming an interposer including a plurality of conductive vias, each conductive via having a first end exposed at a first major side of an interposer substrate and a second end exposed at a second major side of the interposer substrate. A semiconductor die is mounted on the first major side of the interposer substrate. An encapsulant encapsulates the semiconductor die and portions of the first major side of the interposer substrate. A redistribution layer structure is formed over the second major side of the interposer substrate such that the semiconductor die interconnected with the redistribution layer structure by way of the interposer.