Laser-Formed Metallic Interconnects for Flexible Circuits
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Solution Overview
Problem
Traditional electronic manufacturing techniques are inadequate for producing conformal, flexible, and hybrid electronic circuits due to limitations in interconnect generation, particularly with soldering and wire-bonding methods that are bulky and incompatible with low-profile requirements.
Innovation Solution
The development of laser-induced forward transfer (LIFT) and laser direct-write processes for creating low-profile, robust, and electrically conductive interconnects through laser shaping and transfer of metallic beams, enabling the formation of free-standing connections between discrete components that can accommodate strains and deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional soldering or wire-bonding methods are used to create interconnects, then electrical connections are established, but the interconnects become bulky and incompatible with low-profile conformal and flexible circuit requirements
Solution Approach 1:
The patent replaces traditional mechanical interconnect formation methods (soldering, wire-bonding) with a laser-based direct-write process. The laser system melts and deposits metallic powder or foil directly onto the substrate to form interconnects, eliminating the need for mechanical soldering irons, wire bonders, and associated fixtures. This substitution enables low-profile interconnect formation while maintaining electrical reliability.
Solution Approach 2:
The patent controls interconnect profile and properties by varying laser parameters including pulse duration, power, scanning speed, and focal position. By adjusting these parameters, the process produces interconnects with controlled height, width, and cross-sectional area, achieving low-profile structures that are compatible with conformal and flexible circuit requirements while ensuring adequate electrical conductivity.
2Volume of moving object
If printable inks or pastes are used to form interconnects, then low-profile structures are achieved, but the electrical performance is poor and the structures are fragile
Solution Approach 1:
The patent uses composite material systems consisting of metallic powder or foil suspended in a binder matrix. The metallic component (e.g., silver, copper, aluminum powder) provides electrical conductivity, while the binder provides structural integrity. The laser processing selectively melts the metallic particles and binder to form a composite interconnect structure that combines both electrical performance and mechanical robustness in a low-profile configuration.
Solution Approach 2:
The patent employs pulsed laser irradiation with controlled pulse durations and repetition rates. The periodic laser pulses allow for controlled heating, melting, and deposition of the metallic ink or paste material. The pulse timing and duration are optimized to achieve complete melting of metallic particles and binder without excessive heat diffusion, creating robust interconnect structures with good electrical conductivity and mechanical strength in a low-profile form.
3Adaptability or versatility
If conformal and flexible circuit designs are implemented, then three-dimensional configurations and mechanical compliance are achieved, but traditional interconnect methods cause circuit failure under strain
Solution Approach 1:
The patent creates interconnects with dynamic mechanical properties that can accommodate strain and deformation. The laser-formed interconnect structures, particularly those using metallic powder-in-binder composites, exhibit controlled flexibility and elasticity. The interconnect geometry and material composition are optimized to allow bending, stretching, and folding without fracturing, enabling the circuit to maintain electrical connectivity under mechanical strain while conforming to three-dimensional configurations.
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
Enables the fabrication of reliable, high-current conducting interconnects for conformal, flexible, and hybrid electronic circuits, overcoming the limitations of traditional methods by providing low-profile, mechanically and electrically robust connections that withstand typical strains and deformations.
Implementation Method 1
laser-induced forward transfer (LIFT) and laser direct-write processes for creating low-profile, robust, and electrically conductive interconnects through laser shaping and transfer of metallic beams
Implementation Method 2
laser direct-write processes for creating low-profile, robust, and electrically conductive interconnects through laser shaping
Data Source
AI summary
An electronic device made from the method of providing a donor substrate comprising an array of metallic interconnects, using a laser system to prepare the metallic interconnects, forming shaped metallic interconnects, laser bending the shaped metallic interconnects; and transferring the shaped metallic interconnects onto a receiving substrate or device.