Non-Cylindrical Vias in Multilayer Electronic Structures
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Solution Overview
Problem
The existing drill & fill technology for creating vias in multilayer electronic support structures is limited by low throughput, high costs, difficulty in producing high-density vias of varying sizes and shapes, rough laser-drilled via walls, tapering, dimpling, overfill issues, and limitations in via geometry, which hinder the fabrication of high-density, reliable, and thin electronic components.
Innovation Solution
The use of pattern plating and panel plating methodologies to create non-cylindrical via posts with long dimensions in the X-Y plane, allowing for conductive coupling between adjacent feature layers, using a dielectric material sandwiched between feature layers, and electroplating copper into photo-resist patterns to fabricate vias with specific geometries and dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser drilling is used to create vias, then via channels can be formed through dielectric material, but the via walls become rough and tapered, reducing effective diameter and electrical contact quality
Solution Approach 1:
The patent replaces the mechanical laser drilling process with a chemical etching process using photoresist patterning. Instead of using laser energy to ablate material and create rough, tapered holes, the invention uses photolithography to define precise via patterns followed by chemical etching that produces smooth-walled, vertically-sided via channels with accurate dimensional control.
Solution Approach 2:
The invention changes the fundamental parameters of via formation by transitioning from high-energy laser ablation to low-energy chemical etching. This parameter change enables precise control of via geometry, smooth walls, and consistent dimensions while eliminating the tapering and roughness inherent in laser drilling.
2Reliability
If drill & fill methodology is used to create high-density vias, then interconnections can be established, but throughput rate is limited and fabrication costs become prohibitive
Solution Approach 1:
The patent merges the via formation process with the existing photolithography and electroplating workflows. By integrating via creation into the standard pattern plating sequence, the invention eliminates separate laser drilling and individual via filling steps, thereby increasing throughput while maintaining via quality through consistent process integration.
Solution Approach 2:
The invention makes the photolithography and electroplating processes multi-functional, serving both their traditional purposes and via formation simultaneously. This universal application of existing processes eliminates the need for dedicated via drilling equipment and operations, significantly boosting productivity.
3Adaptability or versatility
If different sized via channels are drilled and filled to fabricate different sized vias, then various via geometries can be achieved, but dimpling or overfill problems occur due to different fill rates
Solution Approach 1:
The patent applies preliminary action by forming all via patterns simultaneously through photolithography before any filling occurs. The photoresist layer defines all via geometries at once, and subsequent electroplating fills all vias in a single uniform process, eliminating the sequential filling problems that cause dimpling and overfill in different-sized vias.
4Ease of manufacture
If laser drilling is used to create vias in composite dielectric materials, then via channels can be formed, but via diameter is limited to approximately 60 micrometers due to tapering and roughness
Solution Approach 1:
The patent replaces mechanical laser drilling with chemical etching, enabling via diameters far exceeding the 60 micrometer limit. Chemical etching through photoresist patterning can accommodate any via size constrained only by the photolithography resolution and design requirements, not by the physical limitations of laser beam focus and ablation control.
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 fabrication of high-density, reliable, and thin multilayer electronic support structures with improved electrical performance and reduced inductance, allowing for the creation of complex geometries and high current densities, overcoming the limitations of traditional drill & fill methods.
Implementation Method 1
using a dielectric material sandwiched between feature layers, and electroplating copper into photo-resist patterns to fabricate vias with specific geometries and dimensions
Implementation Method 2
electroplating copper into photo-resist patterns to fabricate vias with specific geometries and dimensions
Data Source
AI summary
A multilayer electronic support structure comprising at least one pair of adjacent feature layers extending in an X-Y plane that are separated by a via layer; said via layer comprising a dielectric material that is sandwiched between the two adjacent feature layers and at least one one non-cylindrical via post that couples said pair of adjacent feature layers through the dielectric material in a Z direction perpendicular to the X-Y plane; wherein said at least one non-cylindrical via post is characterized by having a long dimension in the X-Y plane that is at least 3 times as long as a short dimension in the X-Y plane.