3D Semiconductor Interposer with Internal Vias, Waveguides, and Fluidics
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Solution Overview
Problem
Conventional microfabrication techniques are limited in creating three-dimensional structures with complex geometries and smaller feature sizes, particularly in semiconductor devices, as they are restricted to two-dimensional extruded shapes and straight connections, which hinders the development of advanced MEMS, microfluidic, and micro-optical systems.
Innovation Solution
The use of selective electrochemical etching with sub-bandgap-energy lasers to create three-dimensional features such as vias, waveguides, and fluidic channels within semiconductor elements, allowing for non-linear paths and smaller feature sizes by controlling the creation of holes through multi-photon absorption and electric field focusing, enabling the formation of complex structures like interposers with 3D vias, waveguides, and fluidic channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional microfabrication techniques are used, then manufacturing process is simple and well-established, but manufacturing precision and ability to create complex three-dimensional structures is limited
Solution Approach 1:
The patent replaces conventional mechanical lithographic patterning with a photochemical etching process. Sub-bandgap laser light induces multi-photon absorption in the semiconductor material, creating holes that drive electrochemical etching. This substitution enables three-dimensional structuring without the limitations of traditional layer-by-layer mechanical fabrication, achieving complex geometries with lateral offsets and non-linear paths.
Solution Approach 2:
The patent changes the energy parameter of the laser light to be below the bandgap energy of the semiconductor material. This parameter change enables multi-photon absorption, which allows selective etching at the focal point of the laser beam deep within the material. By controlling laser focus depth and scanning patterns, complex three-dimensional structures with varying geometries can be created throughout the bulk material.
2Adaptability or versatility
If straight-through connections are used, then manufacturing is easier, but adaptability and functionality of interconnections are limited
Solution Approach 1:
The patent transitions from two-dimensional surface connections to three-dimensional bulk connections. Conductive vias and waveguides can now extend through the bulk of the semiconductor material with lateral offsets between entry and exit points. This dimensional change enables complex routing paths, three-dimensional interposer structures, and multi-layer interconnections that were impossible with conventional planar fabrication.
Solution Approach 2:
The patent enables curved and non-linear connection paths within the semiconductor material. Waveguides can follow curved trajectories through the bulk, and conductive vias can be positioned with lateral offsets rather than requiring straight vertical alignment. This curvature capability provides design flexibility for optimizing signal paths, avoiding obstacles, and creating compact three-dimensional layouts.
3Manufacturing precision
If larger feature sizes are used, then manufacturing is more achievable, but device functionality and integration density are reduced
Solution Approach 1:
The patent replaces mechanical lithographic limits with optical focusing capabilities. The sub-bandgap laser can be focused to a diffraction-limited spot size deep within the material, enabling feature dimensions determined by optical physics rather than mechanical constraints. This allows precise creation of small features throughout the bulk material volume, achieving high integration density with three-dimensional structuring.
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 complex three-dimensional semiconductor structures with smaller feature sizes and non-linear paths, facilitating advanced electrical, optical, and fluidic connections between devices, enhancing the capabilities of MEMS, microfluidic, and micro-optical systems.
Implementation Method 1
controlling the creation of holes through multi-photon absorption
Implementation Method 2
selective electrochemical etching with sub-bandgap-energy lasers
Implementation Method 3
The exposed surface of the semiconductor is etched selectively based upon controlled creation of holes in the atomic lattice of the semiconductor
Implementation Method 4
electric field focusing, enabling the formation of complex structures
Data Source
AI summary
Various three-dimensional devices that can be formed within the bulk of a semiconductor by photo-controlled selective etching are described herein. With more particularity, semiconductor devices that incorporate three-dimensional electrical vias, waveguides, or fluidic channels that are disposed within a semiconductor are described herein. In an exemplary embodiment, a three-dimensional interposer chip includes an electrical via, a waveguide, and a fluidic channel, wherein the via, the waveguide, and the fluidic channel are disposed within the body of a semiconductor element rather than being deposited on a surface. The three-dimensional interposer is usable to make electrical, optical, or fluidic connections between two or more devices.