Semiconductor Substrate Separation via Trench Voids and Stress
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Solution Overview
Problem
The existing methods for manufacturing semiconductor substrates, particularly for nitride-based light emitting devices, face challenges in simplifying the process while maintaining quality and reducing defects, especially when using GaN substrates, as they require complex processes and increased manufacturing costs.
Innovation Solution
A method involving the formation of semiconductor layers with trenches and voids on a growth substrate, where the second semiconductor layer with a lower lattice constant than the first layer is used to create tensile stress, allowing for the selective removal of the first layer and subsequent growth of a third layer that covers the trenches, enabling integral separation from the substrate without additional processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods are used to manufacture GaN substrates, then substrate quality can be maintained, but the manufacturing process becomes complex and costs increase
Solution Approach 1:
The patent applies preliminary action by forming a second semiconductor layer with trenches and voids before final substrate separation. The second layer is prepared in advance with specific structural features (trenches and voids) that enable subsequent selective removal of the first layer and facilitate clean separation from the growth substrate, simplifying the overall manufacturing process
Solution Approach 2:
The patent segments the semiconductor structure into multiple functional layers: a first semiconductor layer, a second semiconductor layer with trenches and voids, and a third semiconductor layer. This segmentation allows each layer to serve specific purposes - the second layer acts as a sacrificial mask and stressor, enabling simplified separation processes while maintaining substrate quality
2Ease of manufacture
If additional processing steps are added to simplify substrate separation, then ease of manufacture improves, but device complexity increases
Solution Approach 1:
The patent applies self-service by designing the second semiconductor layer to automatically perform multiple functions: it serves as a mask during etching, creates tensile stress to facilitate separation, and provides structural support during processing. The layer essentially serves itself by having its trenches and voids formed in advance, which then automatically enable the selective removal of the first layer and facilitate substrate separation without requiring additional complex processing steps
Solution Approach 2:
The patent utilizes parameter changes by controlling the lattice constant of the second semiconductor layer to be less than that of the first layer, creating tensile stress that facilitates separation. The thermal expansion coefficient of the third layer is also deliberately made different from the growth substrate, enabling stress-driven separation. These parameter changes enable simplified separation processes
3Reliability
If defects are reduced in nitride-based light emitting devices, then product quality improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies taking out by selectively removing the first semiconductor layer through the trenches and voids in the second layer. This extraction of the first layer eliminates defect sources at the growth substrate interface while preserving the quality of the second and third layers, thereby reducing overall device defects without requiring complex additional processing
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 simplifies the semiconductor substrate manufacturing process, reduces defects, and allows for the production of high-quality substrates suitable for nitride-based light emitting devices without increasing costs, by using the stress differences between layers to facilitate separation and void formation.
Implementation Method 1
a lattice constant value of the second semiconductor layer is less than a lattice constant value of the first semiconductor layer
Implementation Method 2
a thermal expansion coefficient of the third semiconductor layer being different from a thermal expansion coefficient of the growth substrate
Data Source
AI summary
A method of manufacturing a semiconductor substrate may include forming a first semiconductor layer on a growth substrate, forming a second semiconductor layer on the first semiconductor layer, forming a plurality of voids in the first semiconductor layer by removing portions of the first semiconductor layer that are exposed by a plurality of trenches in the second semiconductor layer, forming a third semiconductor layer on the second semiconductor layer and covering the plurality of trenches, and separating the second and third semiconductor layers from the growth substrate. on the first semiconductor layer. The third semiconductor layer are grown from the second semiconductor layer and extend above the second semiconductor layer.