Dual Stiffener Ring Structure for IC Package Warpage Control
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Solution Overview
Problem
High-performance integrated circuit packages experience warpage due to heat generation, which is exacerbated by omitting the package lid for heat dissipation, leading to weakened mechanical structure and reduced production yields.
Innovation Solution
A combination of a primary and secondary stiffener rings, removably attached using twist-lock, snap-lock, or slide-lock mechanisms, provides additional structural support without increasing the height beyond the IC die, and can be magnetically enhanced for enhanced stability during heating and cooling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the package lid is omitted to facilitate heat dissipation, then heat dissipation efficiency is improved, but mechanical structure strength deteriorates and warpage is exacerbated
Solution Approach 1:
The stiffening function is segmented into multiple components: a substrate-level stiffener structure and a separate lidless heat dissipation path. This allows the stiffener to provide mechanical support while the omitted lid maintains direct thermal coupling between heat sink and die, resolving the contradiction between structural strength and heat dissipation efficiency
Solution Approach 2:
A stiffener structure acts as an intermediary element between the substrate and the heat dissipation path. This intermediary provides the necessary mechanical reinforcement without blocking the direct thermal path, thereby maintaining both structural integrity and heat dissipation performance
2Temperature
If the package lid is omitted for direct heat sink path, then heat dissipation is improved, but warpage during heating and cooling cycles is exacerbated
Solution Approach 1:
The stiffener structure is pre-installed on the substrate before the heat dissipation assembly is attached. This preliminary structural reinforcement counteracts the warpage forces that will occur during subsequent heating and cooling cycles, preventing excessive deformation while maintaining the lidless design for heat dissipation
3Strength
If stiffener height is increased to provide structural support, then mechanical strength is improved, but height beyond IC die is increased
Solution Approach 1:
The stiffener is designed with localized reinforcement features such as ribs, fins, or strategic thickness variations in specific areas rather than uniformly increasing height. This provides targeted structural support where needed while keeping the overall stiffener height profiled to not exceed the IC die height, resolving the contradiction between structural support and height constraints
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 stiffener apparatus effectively reduces warpage during manufacturing, maintaining heat dissipation pathways and improving production yields by preventing bond failures and IC failures.
Implementation Method 1
can be magnetically enhanced for enhanced stability during heating and cooling processes
Data Source
Figure 1A~1B
Figure 1C
Figure 2A
AI summary
A stiffener apparatus for reducing warpage of an integrated circuit package during heating and cooling are provided. The stiffener apparatus includes an IC substrate (204) configured to receive an IC die (210) on a top side of the IC substrate. The stiffener apparatus includes a primary stiffener ring (201) adhered to the top side of the IC substrate and defining an opening in a region of the IC die such that the primary stiffener ring surrounds the region of the IC die. The primary stiffener ring defines a plurality of grooves (206). The stiffener apparatus includes a secondary stiffener ring (202) having a plurality of catches (205) configured to engage with the plurality of grooves to removably attach the secondary stiffener ring to the primary stiffener ring on a side of the primary stiffener ring opposite the IC substrate. A method of using a stiffener apparatus during a manufacturing operation is also provided.