Offset Contact Openings in Flip Chip Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increased density and faster switching speeds of integrated circuits, facilitated by low-k dielectrics with air pockets, compromise the mechanical strength of these materials, leading to potential cracking or crushing under stress, which can cause integrated circuit failure.
Innovation Solution
The offset positioning of contact openings in the dielectric layer over contact pads, particularly in peripheral regions, reduces stress on the underlying low-k dielectric layers, combined with smaller contact openings that maintain electrical conductivity, alleviates mechanical stress and electromigration issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-k dielectrics with air pockets are used to reduce capacitance and increase switching speed, then the dielectric constant decreases and switching speed increases, but the mechanical strength and physical integrity of the dielectric layers are significantly reduced
Solution Approach 1:
The patent applies different structural configurations to different regions of the dielectric layers. Specifically, support structures are added in certain local areas where mechanical strength is needed, while maintaining the low-k dielectric material properties in other areas where electrical performance is prioritized. This local differentiation allows the system to achieve both high switching speed and adequate mechanical strength.
2Quantity of substance
If more air pockets are placed in the intermetal dielectric to reduce dielectric constant, then the dielectric constant decreases and chip operation speed increases, but the physical integrity and strength of the dielectric layers are significantly reduced
Solution Approach 1:
The patent employs composite structures combining low-k dielectric materials with air pockets and additional support structures. This composite approach allows the system to maintain the low dielectric constant needed for high-speed operation while incorporating reinforcing elements that provide the necessary mechanical strength and physical integrity to prevent crushing and cracking.
3Ease of manufacture
If contact openings are positioned at the center of contact pads, then alignment is simplified, but stress is concentrated on the underlying low-k dielectric layers causing cracking or crushing
Solution Approach 1:
The patent introduces asymmetric positioning of contact openings relative to contact pads. Instead of centering the openings on the pads, they are deliberately offset to specific locations that avoid high-stress regions. This asymmetric configuration redistributes the mechanical stress more evenly across the dielectric layers, preventing concentration of stress that would lead to cracking or crushing, while still maintaining manufacturability through controlled offset patterns.
Data Source
AI summary
An integrated circuit die has a dielectric layer positioned over all the contact pads on the integrated circuit die. Openings are provided in the dielectric layer over each of the contact pads of the integrated circuit die in order to permit electrical coupling to be made between the integrated circuit and circuit boards outside of the die. For those contact pads located in the central region of the die, the opening in the dielectric layer is in a central region of the contact pad. For those contact pads located in a peripheral region of the die, spaced adjacent the perimeter die, the opening in the dielectric layer is offset from the center of the contact pad and is positioned closer to the central region of the die than the center of the contact pad is to the central region of the die.