Rectangular IC Package with Clustered Contacts for Warpage Stress
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Solution Overview
Problem
Integrated circuit (IC) packaging faces challenges in reliability due to thermal stresses during assembly, leading to electrical contact failure, especially in compact and complex devices where warpage and mechanical stresses are significant, affecting manufacturability and safety.
Innovation Solution
The use of a rectangular IC packaging with leadless surface-mount electrical contacts clustered at opposite ends, providing a rigid connection while minimizing compliance to mechanical forces, and a contact-free span in the middle region to accommodate thermally-induced warping, reducing stress on electrical contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical contacts are distributed across the entire bottom surface of the IC package, then electrical connectivity is improved, but the package becomes more susceptible to warpage-induced stress and contact failure
Solution Approach 1:
The electrical contacts are segmented into two distinct clusters positioned at opposite ends of the package along the length dimension, rather than being distributed uniformly across the bottom surface. This segmentation creates a contact-free span in the middle region that can accommodate warpage deformation, reducing stress on the electrical contacts while maintaining connectivity.
Solution Approach 2:
The package uses a rectangular aspect ratio with length at least 1.5 times the width, creating an elongated geometry that facilitates the clustering of contacts at opposite ends. This dimensional configuration allows the middle span to act as a stress-relief zone, effectively separating the electrical connection function from the mechanical stress-bearing function.
2Volume of moving object
If the IC package uses a compact form factor to meet space constraints, then device size is reduced, but thermal stresses and warpage effects are intensified
Solution Approach 1:
The package employs an asymmetric rectangular footprint with length significantly greater than width (aspect ratio ≥ 1.5:1), rather than a compact square form factor. This asymmetric geometry allows the contacts to be positioned at the longer ends, creating a longitudinal span that can flex to accommodate thermal expansion and warpage while maintaining a space-efficient overall package volume.
3Area of stationary object
If the IC package uses a square aspect ratio to maximize mounting surface area, then PCB mounting area is increased, but the package experiences higher mechanical stresses from thermal expansion
Solution Approach 1:
The invention deliberately uses a rectangular aspect ratio with length at least 1.5 times the width, rejecting the conventional square footprint. This asymmetric rectangular shape provides sufficient mounting surface area while enabling the contact-clustering configuration that creates a stress-relief span, thereby maintaining both adequate mounting area and mechanical strength.
Solution Approach 2:
By segmenting the electrical contacts into two clusters at opposite ends rather than distributing them uniformly across the mounting surface, the invention creates a middle span that can accommodate thermal deformation. This segmentation maintains electrical connectivity while reducing the mechanical stress that would otherwise compromise package strength.
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 configuration enhances manufacturability and reliability by reducing warpage-induced stress and accommodating thermal expansion, while allowing for thinner form factors in size-constrained applications like smart glasses, thereby improving the overall performance and durability of IC packages.
Implementation Method 1
accommodate thermally-induced warping
Data Source
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AI summary
An integrated circuit (IC) packaging arrangement for surface mounting of the IC includes a package body that encapsulates one or more IC dies. The package body according to some embodiments has rectangular aspect ratio with a length dimension and a width dimension of different size. The IC packaging according to some embodiments includes leadless surface-mount electrical contacts. According to some embodiments, the leadless surface-mount contacts are situated in clusters at opposite ends of the length dimension of the IC body.