Semiconductor ICF Target Fabrication via Conformal Deposition
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Solution Overview
Problem
Current semiconductor processing methods are inefficient for high-volume manufacturing of spherical devices, particularly for Inertial Confinement Fusion (ICF) targets, as they lack flexibility in material choices and precision in lithographic pattern and film thickness application.
Innovation Solution
A process involving depositing hard mask layers on a single-crystal n-type silicon substrate, patterning vias, forming hemispherical cavities, incorporating p-type dopant, conformally depositing an ablator/drive region, and a shell layer, followed by placing hollow silicon dioxide fuel spheres within the shell layer, allowing for precise control and flexibility in material choices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional semiconductor processing methods are used for spherical device manufacturing, then existing manufacturing capabilities can be utilized, but manufacturing efficiency and flexibility are insufficient for high-volume production
Solution Approach 1:
The patent segments the manufacturing process into distinct phases (substrate preparation, cavity formation, material deposition, sphere placement) that can be independently optimized and scaled. This segmentation enables parallel processing of multiple targets simultaneously while maintaining flexibility in material selection for each layer.
Solution Approach 2:
The patent creates a universal manufacturing platform that can produce spherical devices with varying material compositions and structures using the same base process flow. The conformal deposition techniques and modular layer structure allow the same equipment and methodology to accommodate different material choices for ablator, drive, and shell regions.
2Manufacturing precision
If conventional processing methods are used, then existing tools can be employed, but precision in lithographic pattern and film thickness application is insufficient
Solution Approach 1:
The patent applies preliminary lithographic patterning to define precise cavity locations and dimensions before material deposition. The hard mask layers are patterned with high precision beforehand, ensuring accurate spatial control of subsequent conformal deposits and sphere placement, thereby achieving high manufacturing precision through pre-planned patterning.
Solution Approach 2:
The patent employs conformal deposition techniques that precisely control film thickness through parameter optimization (deposition time, rate, temperature). By changing and controlling deposition parameters, the process achieves uniform and precise film thickness application across complex spherical geometries, maintaining high precision while managing process complexity.
3Productivity
If high-volume manufacturing is implemented, then production capacity increases, but unit cost reduction must be achieved simultaneously
Solution Approach 1:
The patent merges multiple manufacturing operations into integrated process steps. For example, cavity formation, material deposition, and sphere placement are combined in a sequence that minimizes intermediate handling and equipment transitions. This merging reduces per-unit processing time and cost while maintaining high production capacity through efficient resource utilization.
Solution Approach 2:
The conformal deposition process inherently adapts to the underlying geometry, automatically conforming to spherical cavity shapes without requiring complex tooling or alignment procedures. This self-adjusting capability reduces manufacturing complexity and cost while enabling high-volume production, as the process serves itself by naturally accommodating the target structure geometry.
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 high-volume, cost-effective manufacturing of spherical devices with precise lithographic patterns and film thickness, increasing manufacturing capacity and reducing unit costs while offering flexibility in material choices for ablator and shell regions.
Implementation Method 1
incorporating a p-type dopant into the surface of the hemispherical cavities
Implementation Method 2
depositing one or more hard mask layers upon a single-crystal n-type silicon substrate
Implementation Method 3
conformally depositing an ablator/drive region onto the surface of the hemispherical cavities; conformally depositing a shell layer region onto the ablator/drive region
Data Source
AI summary
A method of manufacturing a semiconductor ICF target is described. On an n-type silicon wafer a plurality of hard mask layers are etched to a desired via pattern. Then isotropically etching hemispherical cavities, lithographically patterning the hard mask layers, conformally depositing ablator/drive material(s) and shell layer material(s), inserting hollow silicon dioxide fuel spheres in the hemisphere cavities, thermally bonding a mating wafer with matching hemisphere cavities and etching in ethylene diamine-pryrocatechol-water mixture to selectively remove n-type silicon and liberate the spherical targets.