Beam-Bridged Chip Package for Thermal Expansion Gap Stability
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Solution Overview
Problem
Conventional chip packages using fan-out wafer-level packaging (FOWLP) and redistribution layers (RDL) face issues with thermal expansion, leading to increased gaps between dies, crack formation, and line breakage, which compromises the reliability and service life of the chip package.
Innovation Solution
The introduction of a beam structure with a lower thermal expansion coefficient than the substrate, which is fixedly connected to adjacent dies and provides a tensile force to maintain the gap stability, thereby reducing the likelihood of line breakage and enhancing the reliability of the chip package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple dies are packaged together to increase integration degree, then chip package size increases, but gap between dies increases due to substrate thermal expansion, causing crack formation and line breakage
Solution Approach 1:
A beam structure is introduced as an intermediary element between adjacent dies to bridge the gap caused by substrate thermal expansion. The beam structure includes a first end connected to a first die and a second end connected to a second die, acting as a mediator that maintains mechanical connection while accommodating substrate deformation.
Solution Approach 2:
The beam structure is designed with a thermal expansion coefficient lower than that of the substrate. This parameter difference allows the beam structure to resist the substrate's thermal expansion more effectively, providing tensile force to counteract gap formation between dies when the substrate expands due to temperature changes.
2Reliability
If substrate thermal expansion is reduced, then gap stability improves, but chip package size is limited
Solution Approach 1:
The beam structure serves as a mechanical intermediary that spans the gap between dies, providing continuous support and maintaining gap stability even when the substrate undergoes thermal expansion. This allows larger chip packages with more dies to be constructed without compromising reliability.
3Reliability
If beam structure is added to maintain gap stability, then reliability improves, but device complexity increases
Solution Approach 1:
The beam structure is segmented into a first end and a second end, with the first end connected to the first die and the second end connected to the second die. This segmentation allows the beam structure to be integrated into existing die arrangements without requiring complete redesign of the chip package architecture.
Solution Approach 2:
The beam structure serves multiple functions simultaneously: it maintains gap stability between dies, provides tensile force to counteract thermal expansion effects, and bridges the mechanical connection between adjacent dies. This multi-functionality reduces the need for additional separate components.
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 beam structure effectively reduces the impact of thermal expansion on the chip package, improving the reliability and service life by maintaining gap stability and preventing line breakage, while also allowing for a larger chip package size without compromising integrity.
Implementation Method 1
A thermal expansion coefficient of the beam structure is less than a thermal expansion coefficient of the substrate. In this case, when the substrate of the chip package mechanically deforms due to thermal expansion or the like, mechanical deformation of the beam structure is less than mechanical deformation of the substrate.
Data Source
AI summary
A chip package includes a substrate, a first die, a second die, and a beam structure. The first die and the second die are disposed on a side of the substrate and are electrically connected to the substrate. The beam structure is disposed between the first die and the second die. A first end of the beam structure is stacked with and fixedly connected to a part of the first die, a second end is stacked with and fixedly connected to a part of the second die, and the beam structure is insulated from and connected to the first die and the second die. A thermal expansion coefficient of the beam structure is less than a thermal expansion coefficient of the substrate.