Flexible Circuit Microchannels for Micron-Level Pad Registration
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Solution Overview
Problem
Current techniques fail to consistently and accurately achieve micron-level registration between solid semiconductor dies and electrically conductive interconnects on flexible substrates in roll-to-roll manufacturing processes, particularly due to substrate distortion and tension control issues.
Innovation Solution
The method involves using a conductive particle-containing liquid that flows through a network of microchannels to electrically interconnect aligned contact pads on semiconductor dies, with the microchannels being part of a guide layer applied over the substrate, allowing for automatic registration and tolerance of misalignment sources like thermal cycles and tension variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If web-based roll-to-roll manufacturing processes are used for flexible hybrid electronics, then high-throughput and form-factor flexibility are achieved, but substrate distortion from thermal cycles and tension control causes misalignment between semiconductor dies and conductive interconnects
Solution Approach 1:
The system uses self-aligning features where the liquid carrier and substrate automatically register to each other through complementary geometric features during the picking and placing process, eliminating the need for complex external alignment mechanisms and achieving consistent micron-level registration throughout the roll-to-roll manufacturing process
Solution Approach 2:
A liquid carrier is introduced as an intermediary between the substrate and the pick-and-place system. The carrier provides a stable reference frame with precisely positioned recesses that receive the substrate, allowing the high-speed pick-and-place mechanism to operate on the liquid carrier while the substrate remains isolated from direct mechanical handling that would cause alignment errors
2Manufacturing precision
If alignment mechanisms suitable for wafer-based semiconductor devices are transferred to web-based processes, then registration accuracy may be improved, but the complexity and adaptability to moving flexible substrates worsens
Solution Approach 1:
The invention replaces complex mechanical alignment mechanisms with a liquid-based carrier system that uses fluid-structure interaction for positioning. The liquid carrier's surface tension and geometric features provide automatic registration without requiring complex mechanical alignment stages or sensors typically needed in wafer-based processes
Solution Approach 2:
The system uses a flexible liquid carrier that can conform to the moving substrate while maintaining precise geometric features for alignment. The liquid nature of the carrier allows it to accommodate substrate movements and thermal expansions without compromising registration accuracy, unlike rigid mechanical alignment systems
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 ensures reliable and accurate micron-level registration, enabling efficient and consistent manufacturing of flexible hybrid electronics by forming electrically conductive traces within the microchannels, even in the presence of substrate distortions and tension control challenges.
Implementation Method 1
automatic registration via flow of a conductive particle-containing liquid through a network of microchannels
Data Source
AI summary
An article includes a solid circuit die on a first major surface of a substrate, wherein the solid circuit die includes an arrangement of contact pads, and wherein at least a portion of the contact pads in the arrangement of contact pads are at least partially exposed on the first major surface of the substrate to provide an arrangement of exposed contact pads; a guide layer including an arrangement of microchannels, wherein the guide layer contacts the first major surface of the substrate such that at least some microchannels in the arrangement of microchannels overlie the at least some exposed contact pads in the arrangement of exposed contact pads; and a conductive particle-containing liquid in at least some of the microchannels. Other articles and methods of manufacturing the articles are described.