Semiconductor Package Stiffener Warpage Control
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Solution Overview
Problem
As multilayer printed circuit boards are miniaturized and slimmed, they experience increased warpage, which can lead to malfunction due to opened solder ball contacts and potential heat-induced damage to semiconductor chips.
Innovation Solution
A semiconductor package design that includes a stiffener extending from one substrate to another without contacting the semiconductor chips, with air gaps between the stiffener and the chip sidewalls to control warpage and temperature transfer, utilizing a thermally conductive material like stainless steel or copper to manage heat and prevent physical stress on the substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multilayer printed circuit boards are miniaturized and slimmed, then the size and thickness are reduced, but warpage increases
Solution Approach 1:
A stiffener is introduced as an intermediary component between the substrates to provide mechanical support and reduce warpage. The stiffener extends from the first substrate to the second substrate, acting as a mediator that counteracts the warping forces without requiring changes to the substrate materials themselves.
Solution Approach 2:
The stiffener's height is specifically designed to be less than the height of the semiconductor chip, creating a height parameter relationship that allows the chip to contact both substrates while the stiffener provides structural support. This parameter optimization resolves the contradiction between miniaturization and warpage control.
2Length of moving object
If substrates are positioned close together, then the package is compact, but heat transfer between chips increases
Solution Approach 1:
Air gaps are introduced as thermal insulating intermediaries between the stiffener and the semiconductor chip sidewalls. These air gaps prevent direct thermal contact while maintaining the compact package structure, allowing close substrate positioning without excessive heat transfer.
3Stability of the object's composition
If a stiffener is added to control warpage, then structural stability improves, but device complexity increases
Solution Approach 1:
The stiffener serves multiple functions simultaneously: it provides mechanical support to reduce warpage, maintains the spacing between substrates, and works with air gaps to control heat transfer. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
4Strength
If the stiffener contacts the semiconductor chip, then structural support is maximized, but heat transfer to the chip increases
Solution Approach 1:
Air gaps are introduced as thermal insulating intermediaries between the stiffener and the semiconductor chip sidewalls. These air gaps prevent direct thermal contact while maintaining the compact package structure, allowing close substrate positioning without excessive heat transfer.
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 reduces warpage and heat transfer to vulnerable semiconductor chips, preventing malfunctions and ensuring reliable operation by maintaining the integrity of the chip connections and substrate alignment.
Implementation Method 1
a stiffener extending from an upper surface of the first substrate to an upper surface of the second substrate
Implementation Method 2
a first air gap between the stiffener and a sidewall of the second substrate
Data Source
AI summary
A semiconductor package is provided. The semiconductor package comprises a first substrate, a second substrate disposed on the first substrate, a first semiconductor chip disposed on the second substrate, and a stiffener extending from an upper surface of the first substrate to an upper surface of the second substrate, the stiffener not being in contact with the first semiconductor chip, wherein a first height from the upper surface of the first substrate to an upper surface of the first semiconductor chip is greater than a second height from the upper surface of the first substrate to an uppermost surface of the stiffener.