Nanostructure Bonding for Fine-Pitch Interconnects
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Solution Overview
Problem
Current technologies for attaching conductive materials, such as flip-chip and Chip On Flex, face limitations in achieving precise connections due to particle size and distribution issues in anisotropic conductive films, leading to risks of short-circuits, misalignment, and manufacturing constraints at finer pitches, which restrict the number and density of contacts.
Innovation Solution
The use of nanostructures, specifically carbon nanostructures grown perpendicular to conductive surfaces and embedded in a polymer matrix, allows for precise mechanical, electrical, or thermal connections between layers, enabling pitches as low as 2 nm to 1 mm and increasing contact density without the need for traditional bumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anisotropic conductive film with conductive particles is used for bonding, then electrical connections can be established, but the risk of short-circuits increases when particles are too close or too numerous
Solution Approach 1:
The patent changes the fundamental parameter of the conductive element from spherical particles to vertically oriented nanostructures (nanotubes, nanofibers, or nanowires). This parameter change allows the conductive elements to maintain electrical connectivity while preventing lateral contact between adjacent elements, thereby eliminating short-circuit risks while maintaining connection reliability.
Solution Approach 2:
The conductive bonding interface is segmented into discrete vertical nanostructure columns that are electrically isolated from each other laterally. Each nanostructure acts as an independent conductive channel, preventing electrical shorting between adjacent bonding locations while maintaining reliable electrical connection at each location.
2Ease of manufacture
If traditional bonding processes are used, then connections can be made, but manufacturing complexity increases due to multiple process steps
Solution Approach 1:
The conductive nanostructures are pre-formed on a carrier substrate before the bonding process. This preliminary preparation allows the nanostructure array to be manufactured and characterized separately, simplifying the final bonding process to primarily alignment and attachment steps, thereby reducing overall manufacturing complexity.
Solution Approach 2:
The nanostructure array on the carrier serves multiple functions: it provides the conductive bonding elements, acts as a structural support framework, and enables alignment features for precise positioning. This multi-functionality reduces the need for separate components and process steps.
3Quantity of substance
If particle size is reduced to achieve finer pitch, then contact density increases, but manufacturing precision requirements increase
Solution Approach 1:
The conductive elements transition from zero-dimensional spherical particles to one-dimensional vertical nanostructures. This dimensional change allows the conductive function to be achieved through vertical orientation rather than lateral packing, enabling finer pitch without proportionally increasing manufacturing precision requirements for element placement.
Solution Approach 2:
The patent changes the geometry parameter from spherical particles to vertically oriented nanostructures with controlled aspect ratios. This parameter change allows the horizontal spacing (pitch) to be reduced while the vertical dimension maintains the conductive function, thereby increasing contact density without proportionally increasing precision requirements.
4Quantity of substance
If more conductive particles are used to increase contact density, then the number of I/O contacts increases, but the risk of misalignment and short-circuits increases
Solution Approach 1:
The bonding interface is segmented into discrete vertical nanostructure columns that are inherently isolated from each other. This segmentation allows a high number of contacts to be packed closely together without increasing misalignment risks, as each vertical column maintains independent electrical isolation from adjacent columns.
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 approach reduces the risk of short-circuits and misalignment, increases contact density, and enables finer pitches by replacing particles with nanostructures, improving the reliability and efficiency of connections in electronic devices.
Implementation Method 1
growing a density of nanostructures on a first conducting surface with a plurality of intermediate layers between the first conducting surface and the nanostructures
Implementation Method 2
curing the pads, such that the first pad is bonded to the first conducting surface and the second pad is bonded to the second conducting surface
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An apparatus, comprising two conductive surfaces or layers and a nanostructure assembly bonded to the two conductive surfaces or layers to create electrical or thermal connections between the two conductive surfaces or layers, and a method of making same.