Method for industrial manufacturing of a semiconductor structure with reduced bowing
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Solution Overview
Problem
Semiconductor structures used in power electronics, photonics, and solar energy conversion face issues with residual thermal stresses, leading to bowing and microcrack formation, which complicates further processing and is difficult to scale industrially.
Innovation Solution
A method involving a first semiconductor layer with pillars extending from a substrate and a second layer with portions joined to the pillars, where the aspect ratio of the pillars depends on the dimensions of the second layer, using non-linear functions to optimize stress reduction and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bulk layer is coated with a thick film of another semiconductor material, then the semiconductor structure can be used for power electronics and photonic devices, but residual thermal stresses cause bowing and microcrack formation
Solution Approach 1:
The patent segments the continuous thick film into multiple sub-layers (first thick film layer and second thick film layer) with different materials and properties. This segmentation allows each sub-layer to accommodate thermal stresses differently, preventing bowing and microcrack formation while maintaining the overall thickness needed for device applications
Solution Approach 2:
The patent uses composite material structures where the bulk layer is coated with multiple layers of different semiconductor materials (e.g., SiC, SiO2, Si3N4) with varying thermal expansion coefficients and mechanical properties. This composite approach enables stress management across the interface regions, resolving the contradiction between achieving thick film functionality and preventing stress-induced defects
2Reliability
If sandwich-type semiconductor structures are used to compensate residual thermal stresses, then bowing is reduced, but the structures become very fragile and difficult to handle
Solution Approach 1:
The patent applies different material properties and thicknesses at different locations and interfaces within the structure. Specifically, the first and second thick film layers have different compositions and thicknesses tailored to their respective positions, providing localized stress compensation while maintaining overall structural integrity and reducing fragility
Solution Approach 2:
The patent modifies material parameters (composition, thickness, thermal expansion coefficient) of the thick film layers to optimize both stress compensation and mechanical strength. By carefully selecting and adjusting these parameters, the structure achieves reduced bowing while maintaining sufficient strength for handling and further processing
3Manufacturing precision
If the thick film thickness exceeds a few micrometers for industrial applications, then the structures are subject to excessive bowing, but reducing thickness limits device manufacturing capabilities
Solution Approach 1:
The patent divides the thick film into multiple sub-layers, each with controlled thickness. This segmentation allows the total equivalent thickness to remain sufficient for device manufacturing (maintaining versatility) while each individual sub-layer thickness remains below the critical threshold that causes excessive bowing (maintaining manufacturing precision)
Solution Approach 2:
The patent employs composite thick film structures where multiple layers with different mechanical and thermal properties work together. This composite approach enables the structure to support greater total thickness needed for device applications without experiencing excessive bowing, as each layer contributes differently to stress distribution
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 significantly reduces residual thermal stresses, enhances the industrial scalability of semiconductor structures, and facilitates the manufacturing of electronic devices by ensuring high aspect ratios and compatibility with existing processing techniques.
Implementation Method 1
These residual thermal stresses, resulting from the different coefficients of thermal expansion of the semiconductor materials that form the superimposed layers
Data Source
AI summary
A method for manufacturing a semiconductor structure with reduced bowing for applications in the field of power electronics, photonics, optoelectronics, solar energy conversion and the like, which comprises: a step of providing at least a first layer of a first semiconductor material, said first layer comprising a substrate of said first semiconductor material, which extends along a first reference plane, and a plurality of first portions of said first semiconductor material, which are mutually spaced and extend in elevation from said substrate along axes perpendicular to said first reference plane, said first portions having ends in distal position with respect to said substrate; a step of providing at least a second layer of a second semiconductor material, said second layer comprising second portions of said second semiconductor material, each of which is joined to the ends of a plurality of said first portions, said second portions being mutually spaced and extending along a second reference plane parallel to said first reference plane; The first portions of the first layer are produced with an aspect ratio that depends on a dimension of said second portions, measured along said second reference plane. In a further aspect thereof, the invention relates to a semiconductor structure for applications in the field of power electronics, photonics, optoelectronics, solar energy conversion and the like.