SOI Semiconductor Structure Using Sacrificial Layer and Oxide Fill
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in achieving high-quality substrates with reduced defect rates and complex, costly manufacturing methods, particularly in the formation of silicon-on-insulator (SOI) structures.
Innovation Solution
A simplified CMOS-compatible process flow for fabricating semiconductor structures that eliminates the need for bonding wafers, allows for high-quality insulator deposition, and enables semiconductor material growth on another semiconductor material, using a sacrificial layer and epitaxial seed area to improve substrate quality and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional wafer bonding processes are used to form SOI structures, then substrate quality can be maintained, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent extracts and eliminates the wafer bonding step from the traditional SOI fabrication process. Instead of bonding a handle wafer to a device wafer, the invention uses a single wafer approach where an insulator layer is deposited directly on the substrate, and a sacrificial layer is formed and removed to create the SOI structure, thereby simplifying the manufacturing process while maintaining substrate quality
Solution Approach 2:
The patent segments the fabrication process into distinct stages: forming the insulator layer, depositing the sacrificial layer, patternning, etching, and final SOI structure formation. This segmentation allows for better process control and quality management at each stage, maintaining substrate quality while enabling a simpler overall process flow
2Volume of moving object
If device size is reduced to achieve miniaturization, then device density increases, but defect rates in substrates must similarly decrease
Solution Approach 1:
The patent performs preliminary actions to ensure high substrate quality before device fabrication begins. The insulator layer is deposited with high quality on a clean substrate, and the sacrificial layer is formed with precise control. These preliminary steps establish a defect-free foundation that enables subsequent miniaturization without compromising substrate quality
Solution Approach 2:
The patent changes key process parameters including insulator layer thickness, sacrificial layer composition and thickness, and etching conditions to optimize the SOI structure for miniaturized devices. These parameter adjustments ensure that substrate quality and defect rates are controlled even as device dimensions are reduced
3Manufacturing precision
If complex manufacturing processes are used to achieve high substrate quality, then substrate performance improves, but manufacturing cost increases
Solution Approach 1:
The patent removes the expensive wafer bonding step from the manufacturing process. By using a single-wafer approach with direct insulator deposition and sacrificial layer removal, the process eliminates the need for handling, aligning, and bonding multiple wafers, thereby significantly reducing manufacturing cost while maintaining high substrate quality
Solution Approach 2:
The patent uses a sacrificial layer that is intentionally deposited and then completely removed after serving its purpose of defining the SOI structure. This disposable layer enables a simpler, cheaper process compared to traditional bonding methods, as it avoids the need for expensive bonding equipment and processes while achieving the same structural outcome
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
The proposed method results in improved substrate structures with enhanced insulator quality, reduced parasitic capacitance, lower leakage currents, and higher power efficiency, while minimizing defects and simplifying the manufacturing process.
Implementation Method 1
an oxide layer over the base substrate
Implementation Method 2
enables semiconductor material growth on another semiconductor material, using a sacrificial layer and epitaxial seed area
Data Source
AI summary
Methods and associated devices including the fabrication of a semiconductor structure that provides a silicon-on-insulator substrate. The semiconductor structure may be formed by providing a base substrate, forming a sacrificial layer over the base structure, and forming a semiconductor layer over the sacrificial layer. The sacrificial layer is removed to form a void that is filled with oxide. The semiconductor structure includes a dielectric support feature extending through the semiconductor and oxide layers and/or a portion of the oxide layer extends to the surface of the semiconductor layer.