Hybridization Bump Structure for Fine-Pitch Sensor Misalignment
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Solution Overview
Problem
Infrared Focal Plane Arrays face challenges with flip-chip interconnects, particularly in Ultra Fine Pitch systems, where high quality bump connections require precise alignment and large height-to-diameter ratios, and misalignment can lead to shorted detectors and weakened connections.
Innovation Solution
A system utilizing hybridization bumps of different material hardness and diameter, where harder bumps with a c-shape penetrate softer bumps, allowing for improved alignment tolerance and electrical communication, with the harder bumps being Ni or Ag and softer bumps being In, accommodating misalignment through larger diameter and c-shaped cross-sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large bump height to diameter ratio is used to improve connection quality, then bump connection strength is improved, but alignment precision requirement increases making manufacturing more difficult
Solution Approach 1:
The patent changes the material hardness parameter of the bump, using a harder material that maintains structural integrity with a smaller height-to-diameter ratio, thereby reducing alignment precision requirements while maintaining connection strength
Solution Approach 2:
The patent employs composite bump structures with different material properties, combining harder materials for structural support with softer materials for alignment tolerance, creating a multi-material solution that resolves the contradiction between strength and manufacturing precision
2Reliability
If precise alignment is required for bump connections, then connection quality is improved, but operability decreases due to shorted detectors and weakened connections from misalignment
Solution Approach 1:
The patent modifies the bump material hardness parameter to be harder, which maintains connection quality while reducing sensitivity to misalignment, thereby improving operability without sacrificing reliability
Solution Approach 2:
The patent designs the bump structure with inherent alignment tolerance that cushions against misalignment effects, preventing shorted detectors and weakened connections before they occur, thus maintaining both connection quality and operability
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 solution enhances the operability and performance of Ultra Fine Pitch IRFPAs by reducing bump flattening, improving alignment, and increasing contact area, thereby relaxing alignment tolerance and preventing shorting.
Implementation Method 1
The first plurality of hybridization bumps have a different material hardness from the second plurality of hybridization bumps
Implementation Method 2
Pressing some material of the second plurality of bumps into c-shaped openings in the first plurality of bumps
Data Source
AI summary
A system includes a die with a first plurality of hybridization bumps extending therefrom, electrically connected to circuitry die. An external circuitry component with a second plurality of hybridization bumps extending therefrom, electrically connected to circuitry in the external circuitry component. The first plurality of hybridization bumps and the second plurality of hybridization bumps are pressed together for electrical communication between the die and the external circuitry component. The first plurality of hybridization bumps have a different material hardness from the second plurality of hybridization bumps. The first plurality of hybridization bumps have a different bump diameter from that of the second plurality of hybridization bumps.