Conductive Paste Sintering for Multilayer PCB Interconnects
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Solution Overview
Problem
The challenge in creating high-density circuitized substrates with organic dielectric materials is to efficiently interconnect conductive layers in a minimal space while avoiding damage to the dielectric layers during the lamination process, which is crucial for advanced PCBs and chip carriers that require multiple layers and precise connections.
Innovation Solution
A conductive paste comprising nano-particles and possibly micro-particles, solder particles, conducting polymers, and an organic component is used to form electrical connections between conductive layers, allowing for sintering and melting during lamination without exceeding the dielectric's melting point, thus forming robust and reliable circuit paths without harming the dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-temperature conductive paste is used to form electrical connections between conductive layers, then reliable electrical connections are achieved, but the dielectric layers are damaged during the lamination process due to excessive temperature
Solution Approach 1:
The patent changes the temperature parameter of the conductive paste from conventional high-temperature (exceeding dielectric melting point) to low-temperature (below dielectric melting point). The conductive paste comprises metal particles (silver, copper, or alloy), organic vehicle, and sintering aid, formulated to sinter at temperatures below the dielectric melting point, thus achieving reliable electrical connections without damaging the dielectric layers
Solution Approach 2:
The patent uses a composite conductive paste material consisting of metal particles (silver, copper, or alloy), organic vehicle, and sintering aid. This composite formulation enables the paste to achieve low-temperature sintering while maintaining good electrical conductivity and bonding strength, resolving the contradiction between connection reliability and dielectric protection
2Productivity
If multiple conductive layers are stacked to achieve high-density circuits, then circuit functionality is improved, but the lamination process becomes more complex and risks damaging dielectric layers
Solution Approach 1:
The patent applies conductive paste to openings in dielectric layers before stacking and lamination. The paste is positioned in advance in the openings, so that during the subsequent lamination process, the paste sinters to form conductive paths connecting multiple layers. This preliminary action simplifies the overall manufacturing process by combining connection formation with the lamination step itself
Solution Approach 2:
The patent merges the connection formation process with the lamination process. The conductive paste is applied before stacking, and during lamination, the heat and pressure simultaneously bond the dielectric layers together and sinter the conductive paste to form electrical connections. This merging eliminates the need for separate connection formation steps, reducing process complexity while enabling high-density multilayer circuits
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 enables the formation of high-density circuitized substrates with enhanced electrical connections and reduced resistance, allowing for efficient signal transmission and robust joint formation, suitable for complex electronic structures like information handling systems.
Implementation Method 1
the flakes of the metallic component are sintered to form a conductive path through the dielectric
Implementation Method 2
allowing for sintering and melting during lamination without exceeding the dielectric's melting point
Data Source
AI summary
A circuitized substrate which includes a conductive paste for providing electrical connections. The paste, in one embodiment, includes a metallic component including nano-particles and may include additional elements such as solder or other metal micro-particles, as well as a conducting polymer and organic. The particles of the paste composition sinter and, depending on what additional elements are added, melt as a result of lamination to thereby form effective contiguous circuit paths through the paste. A method of making such a substrate is also provided, as is an electrical assembly utilizing the substrate and including an electronic component such as a semiconductor chip coupled thereto.