Epitaxial Film Substrate Removal via Sacrificial Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for fabricating semiconductor devices with epitaxial structures face high fabrication costs and potential damage from residual stress due to the removal of temporary substrates, such as sapphire, using laser lift-off or mechanical polishing processes.
Innovation Solution
A method involving the formation of a layered structure with sacrificial film regions and valley-and-peak areas on a temporary substrate, followed by lateral epitaxial growth of an epitaxial film layer, creation of grooves to divide the film, and removal of the temporary substrate through etching, reducing contact area and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser lift-off process is used to remove temporary substrate, then substrate removal is achieved, but fabrication cost increases
Solution Approach 1:
The patent uses a disposable sacrificial film layer that is intentionally designed to be removed after serving its temporary purpose of enabling epitaxial growth. This sacrificial film is much cheaper than laser lift-off processes, replacing expensive substrate removal methods with a low-cost sacrificial material approach.
Solution Approach 2:
The sacrificial film layer acts as an intermediary between the temporary substrate and the epitaxial film layer. It enables the epitaxial growth process to occur on the temporary substrate while providing a easy-to-remove intermediate layer that facilitates subsequent substrate removal without requiring expensive laser lift-off equipment or processes.
2Ease of manufacture
If mechanical polishing process is used to remove temporary substrate, then substrate removal is achieved, but residual stress damages epitaxial film layer
Solution Approach 1:
The sacrificial film layer is designed as a disposable intermediate layer that can be easily removed through chemical etching or other non-mechanical means, avoiding the mechanical stress and residual damage that would be caused by polishing processes. The sacrificial film performs its function and is then discarded without compromising the epitaxial structure.
Solution Approach 2:
The patent replaces mechanical polishing processes with chemical etching or other non-mechanical removal methods for eliminating the temporary substrate. The sacrificial film layer can be selectively removed through chemical means that do not impose mechanical stress on the brittle epitaxial film layer, thereby preserving structural integrity.
3Productivity
If conventional substrate removal methods are used, then temporary substrate is removed, but process time and cost increase
Solution Approach 1:
The sacrificial film layer is deposited in advance during the initial fabrication process, before epitaxial growth occurs. This preliminary action creates a pre-configured structure where the sacrificial film is already positioned between the temporary substrate and the epitaxial layer, enabling rapid subsequent removal without requiring time-consuming intermediate processing steps.
Solution Approach 2:
The sacrificial film layer is designed as a temporary, disposable component that facilitates rapid process progression. Its presence enables quick substrate removal through simple chemical etching, significantly reducing the time required compared to conventional methods while adding minimal complexity to the overall fabrication process.
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 enhances the speed and cost-effectiveness of substrate removal while minimizing residual stress, ensuring the structural integrity and performance of semiconductor devices.
Implementation Method 1
growing laterally and epitaxially an epitaxial film layer over the sacrificial film regions and the valley-and-peak areas
Implementation Method 2
removing the temporary substrate and the sacrificial film regions from the epitaxial structures by etching the sacrificial film regions through the gaps and the grooves
Data Source
AI summary
A method for fabricating semiconductor devices includes: (a) forming a layered structure that includes a temporary substrate, a plurality of spaced apart sacrificial film regions on the temporary substrate, and a plurality of valley-and-peak areas among the sacrificial film regions; (b) growing laterally and epitaxially an epitaxial film layer over the sacrificial film regions and the valley-and-peak areas, wherein gaps are formed among the epitaxial film layer and the valley-and-peak areas; (c) forming a conductive layer to contact the epitaxial film layer; (d) forming a plurality of grooves to divide the epitaxial film layer and the conductive layer into a plurality of epitaxial structures on the temporary substrate; and (e) removing the temporary substrate and the sacrificial film regions from the epitaxial structures by etching the sacrificial film regions through the gaps and the grooves.