Solderless Electronic Assembly via Reverse-Interconnection Process
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Solution Overview
Problem
The electronics industry faces challenges with the use of solder alloys, particularly lead-based solders, due to environmental concerns, health hazards, and inefficiencies in manufacturing, such as the need for high temperatures, brittleness, and reliability issues, as well as the difficulty in connecting small IC components and managing heat in densely packed assemblies.
Innovation Solution
The development of a solderless electronic assembly method using a reverse-interconnection process (RIP) that eliminates the need for circuit boards and solder, involving pre-tested components encapsulated with insulating material and vias for conductive connections, allowing for dense packaging and improved heat dissipation without the use of solder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional soldering methods are used, then reliable electrical connections are achieved, but toxic lead and environmental harm occur
Solution Approach 1:
The patent removes the harmful soldering process and lead-based materials from the electronic assembly system entirely. Instead of using solder to join components to PCBs, the invention extracts this function by using mechanical insertion into recesses followed by epoxy encapsulation, thereby eliminating toxic lead and soldering fumes while maintaining reliable electrical connections.
Solution Approach 2:
The patent replaces the thermal-mechanical soldering process with a purely mechanical insertion system combined with chemical encapsulation. Components are mechanically inserted into precision recesses on the PCB, and electrical connectivity is achieved through conductive epoxy material that fills the interface, substituting the traditional heat-based soldering mechanism with a room-temperature mechanical-chemical process.
2Volume of moving object
If component density is increased, then smaller electronic devices are achieved, but manufacturing complexity and precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-forming precise recesses in the PCB during PCB manufacturing, before component assembly. These recesses include integrated alignment features, mechanical retention structures, and conductive pathways. By preparing the PCB substrate in advance with all necessary structural and electrical features, the actual component assembly process becomes simpler and more tolerant, enabling high density without proportionally increasing assembly precision requirements.
Solution Approach 2:
The patent merges multiple functions into the PCB substrate itself: mechanical support structure, electrical connectivity pathways, alignment reference features, and retention mechanisms are all integrated into the PCB design. This consolidation eliminates the need for separate assembly steps for each function, allowing components to be densely packed while maintaining manufacturing feasibility through a unified substrate design approach.
3Object-affected harmful factors
If lead-free solders are used, then environmental compliance is improved, but joining reliability and strength are reduced
Solution Approach 1:
The patent uses composite materials to achieve both environmental compliance and joint strength. The system combines the PCB substrate material, conductive epoxy material with embedded metallic particles, and component leadframe materials into a integrated assembly. The conductive epoxy acts as both the joining medium and the electrical conductor, creating a composite joint structure that provides mechanical strength, electrical connectivity, and environmental compliance simultaneously, eliminating the need for separate solder joints.
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 manufacturing waste, material usage, and processing steps, enhances reliability, and provides better thermal performance and shielding, while minimizing environmental impact and production costs, resulting in lower-profile, more robust electronic assemblies.
Implementation Method 1
The conductive epoxy material is applied to the PCB in the recesses and heated and pressed to form electrical and mechanical bonds
Implementation Method 2
The conductive epoxy material forms electrical and mechanical bonds between component leads and the PCB
Implementation Method 3
The electronic assembly is encapsulated in a protective material such as epoxy or silicone rubber
Data Source
AI summary
The present invention provides an electronic assembly 400 and a method for its manufacture 800, 900, 1000 1200, 1400, 1500, 1600, 1700. The assembly 400 uses no solder. Components 406, or component packages 402, 802, 804, 806 with I/O leads 412 are placed 800 onto a planar substrate 808. The assembly is encapsulated 900 with electrically insulating material 908 with vias 420, 1002 formed or drilled 1000 through the substrate 808 to the components' leads 412. Then the assembly is plated 1200 and the encapsulation and drilling process 1500 repeated to build up desired layers 422, 1502, 1702. Assemblies may be mated 1800. Within the mated assemblies, items may be inserted including pins 2202a, 2202b, and 2202c, mezzanine interconnection devices 2204, heat spreaders 2402, and combination heat spreaders and heat sinks 2602. Edge card connectors 2802 may be attached to the mated assemblies.