Package-on-Package Thermal Interface Material Layer Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Package-on-package (POP) devices face challenges in heat dissipation due to increased thickness and difficulty in releasing heat generated from semiconductor chips, leading to potential false operations and speed delays.
Innovation Solution
Incorporating a thermal interface material layer with a thermal conductivity of 2 W/m·K or greater, contacting at least 70% of the top surface area of the lower semiconductor chip, and a method involving applying this material between stacked semiconductor packages and pressing with a weight to form a connection solder ball, enhancing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple semiconductor packages are stacked to form a POP device, then the integration density is improved, but the total thickness increases and heat dissipation becomes more difficult
Solution Approach 1:
The patent implements package-on-package stacking where upper semiconductor packages are mounted on lower packages, creating a nested vertical structure. This nesting approach increases integration density by utilizing the vertical dimension while managing the thickness through optimized package design and thermal interface materials.
Solution Approach 2:
The transition from planar 2D packaging to vertical 3D stacking represents a dimensional change that improves integration density. By moving to the third dimension (vertical stacking), the system achieves higher component density without proportionally increasing the footprint area.
2Productivity
If multiple semiconductor packages are stacked to form a POP device, then the integration density is improved, but heat dissipation capability deteriorates
Solution Approach 1:
Thermal interface materials are introduced as intermediary substances between semiconductor chips and heat dissipation structures. These materials fill gaps and improve thermal coupling, enabling effective heat transfer from the chips through the package substrates to external heat sinks, thus resolving the heat dissipation challenge in stacked configurations.
Solution Approach 2:
The patent specifies thermal interface materials with minimum thermal conductivity values (≥2 W/m·K) to ensure adequate heat transfer. By changing the thermal parameters of the interface materials, the system maintains effective heat dissipation despite the added thermal resistance from multiple package layers.
3Temperature
If thermal interface material is applied between semiconductor chips and package substrates, then heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
Thermal interface materials are applied to chip surfaces or package substrates before the mounting process. This preliminary application ensures proper thermal contact is established during subsequent assembly steps, simplifying the overall manufacturing process by integrating thermal management into the existing assembly sequence rather than adding separate thermal treatment steps.
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
Effectively improves heat release from semiconductor chips, reducing the risk of false operations and enhancing operating speed by ensuring efficient thermal management.
Implementation Method 1
A thermal interface material layer disposed between the lower semiconductor chip and the upper package substrate. The contact area of the thermal interface material layer contacting a top surface of the lower semiconductor chip may be equal to or greater than 70% of an area of the top surface of the lower semiconductor chip.
Data Source
AI summary
Package-on-package (POP) devices and methods of manufacturing the POP devices are provided. In the POP devices, a thermal interface material layer disposed between lower and upper semiconductor packages may contact about 70% or greater of an area of a top surface of a lower semiconductor chip. According to methods, the upper semiconductor package may be mounted on the lower semiconductor chip using a weight.