Sacrificial Spacer Layer for Precision Air Gap Fabrication
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Solution Overview
Problem
Existing semiconductor manufacturing processes for creating air gaps in optical devices are inefficient and costly, often requiring multiple processing steps to form both the component and the accompanying gap, making them time-consuming and expensive.
Innovation Solution
A method using a sacrificial spacer layer is employed, where a substrate resistant to removal agents is selected, and a sacrificial layer is deposited along with a blocking layer. The sacrificial layer is then partially removed, creating a gap between the blocking layer and the substrate, allowing for precise etching of the substrate beneath the gap, thereby forming a precision gap for further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple processing steps are used to form both the component and the accompanying gap, then the air gaps can be created in optical devices, but the process becomes time-consuming and expensive
Solution Approach 1:
A sacrificial spacer layer is deposited in advance between the waveguide and the mirror structure before final assembly. This preliminary placement of the spacer eliminates the need for multiple subsequent processing steps to create the air gap, as the gap structure is already prepared in advance.
Solution Approach 2:
The sacrificial spacer layer acts as an intermediary element that temporarily occupies the space where the air gap will eventually form. By using this intermediate material layer, the process simplifies gap creation while maintaining precise dimensional control during manufacturing.
2Manufacturing precision
If multiple processing steps are used to form both the component and the accompanying gap, then the air gaps can be created in optical devices, but the process becomes complex and costly
Solution Approach 1:
The deposition of the sacrificial spacer layer is combined with other layer deposition steps in the manufacturing process. By merging the spacer creation with existing process steps rather than adding separate dedicated steps, the overall process complexity is reduced while still achieving precise air gap formation.
3Measurement precision
If electron beam lithography is used to define etch masks for resonant gaps, then the necessary resolution is achieved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The sacrificial spacer layer is designed as a temporary, disposable element that is deposited using standard lithography techniques rather than requiring electron beam lithography. This disposable layer can be easily removed after serving its spacing function, eliminating the need for high-resolution electron beam processing while maintaining adequate gap dimensions.
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 method enables the efficient and cost-effective creation of precision gaps in optical devices, allowing for enhanced performance in semiconductor structures such as Bragg gratings and quantum wires, while reducing the complexity and time required for processing.
Implementation Method 1
depositing a sacrificial layer along the step and the substrate, the sacrificial layer being removable by an agent to which the step and the substrate is resistant
Data Source
AI summary
The present invention is a method of fabricating a patterned device using a sacrificial spacer layer. The first step in this process is to select an appropriate substrate and form a step thereon. The sacrificial layer is then applied to the substrate and a blocking layer is deposited on the sacrificial layer. The blocking layer is etched back to define the mask for the semiconductor structure and the sacrificial layer is removed. The substrate is then etched using the gap created by removal of the sacrificial layer.