Anisotropic Conductive Substrates for Vertical Connectivity
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Solution Overview
Problem
Existing vertical electrical connection products, such as through substrate vias, face challenges including high costs, complex manufacturing processes, and limited versatility due to their specificity to particular circuits or devices. Additionally, the use of nonconductive base materials like passivated silicon or glass is expensive and difficult to source, and the techniques for plating metal pillars can result in uneven thicknesses.
Innovation Solution
A universal substrate that is conductive in a vertical axis and nonconductive in an orthogonal axis, featuring a multipurpose pattern and configuration. This substrate includes a plurality of conductors with conductive pathways between two connection surfaces, surrounded by a nonconductive matrix that isolates the conductors. This allows for randomized and unplanned electrical connections between devices and components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through substrate vias are used for vertical electrical connections, then electrical connectivity between devices is achieved, but manufacturing complexity and cost increase due to precise via formation and alignment requirements
Solution Approach 1:
The substrate is segmented into conductive regions and nonconductive regions, with conductors embedded only in the conductive regions. This segmentation eliminates the need for through-substrate vias, as connections are established through the conductive regions at the surface level, significantly reducing manufacturing complexity while maintaining electrical connectivity.
Solution Approach 2:
Solder balls serve as intermediaries between the conductors in the conductive regions and the devices to be connected. This intermediary approach simplifies the connection process by eliminating precise alignment requirements for through-substrate vias, as the solder balls self-align during the bonding process.
2Stability of the object's composition
If nonconductive base materials like passivated silicon or glass are used, then substrate integrity is maintained, but cost and sourcing difficulty increase
Solution Approach 1:
The substrate exhibits local quality by having conductive regions where conductors are embedded and nonconductive regions where they are not. This local differentiation allows the use of cheaper, easier-to-source materials for the substrate base, while conductivity is provided only where needed through the embedded conductors, reducing overall material cost and sourcing difficulty.
Solution Approach 2:
The substrate is constructed as a composite material system combining a base substrate material with embedded conductors in specific regions. This composite approach allows optimization of each component independently, enabling the use of cost-effective base materials while achieving the required electrical properties through the conductor-substrate composite structure.
3Reliability
If plated metal pillars are used for connections, then electrical connectivity is established, but uniform thickness plating becomes difficult when products have varying heights and thicknesses
Solution Approach 1:
Instead of forming conductors first and then plating, the invention inverts the process by embedding conductors in the substrate and then applying solder balls on top. This inversion eliminates the plating step entirely, avoiding the uniformity issues that arise with varying product heights and thicknesses, while still achieving reliable electrical connectivity.
Solution Approach 2:
The invention replaces expensive, precision-critical plating processes with simpler, more tolerant solder ball connections. Solder balls are more forgiving of dimensional variations and can be applied without the stringent uniformity requirements of plating, effectively substituting a less precise but more versatile connection method.
4Reliability
If solder balls are used for connections, then electrical connectivity is achieved, but precise alignment of mask or ball drop machine with part is required
Solution Approach 1:
The conductive regions are designed to provide equipotential connection areas that accommodate solder ball placement tolerance. By creating large enough conductive regions and optimizing their electrical properties, the system becomes less sensitive to precise alignment, as multiple solder balls can connect to the same conductive region, providing redundancy and tolerance to misalignment.
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 universal substrate enables efficient and cost-effective connectivity between various types of devices and circuits, reducing manufacturing complexity and increasing versatility. It allows for conductivity between devices at any two coaxial positions, providing electrical or thermal connectivity as needed.
Implementation Method 1
The presently disclosed anisotropic substrate enables designers of electronic devices (such as device-on-device products) or integrated circuits to connect varying types of device and circuits with the anisotropic substrate given a multipurpose pattern and/or configuration. The anisotropic substrate is conductive, either electrically or thermally, in a first or vertical axis, while being nonconductive, either electrically or thermally, in a second axis that is orthogonal to the first axis.
Data Source
AI summary
A method fabricating at least one universal substrate from a batch product. The method includes steps of: providing a preform having a predetermined profile; wrapping a plurality of conductors about an outer surface of the preform; injecting a nonconductive matrix between conductors of the plurality of conductors, wherein the nonconductive matrix permeates between interstitial spaces of the plurality of conductors to isolate some conductors of the plurality of conductors from one another; forming the batch product that includes the plurality of conductors and the nonconductive matrix; and wafering at least one section of the batch product to form the at least one universal substrate. The plurality of conductors of the at least one universal substrate defines a first connection surface, a second connection surface opposite to the first connection surface, and a plurality of conductive pathways defined between the first connection surface and the second connection surface.