Monocrystalline Layer Transfer With Sub-0.1° Crystal Axis Alignment
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Solution Overview
Problem
Current methods for manufacturing composite structures with thin monocrystalline layers, such as silicon carbide, face challenges in achieving precise alignment on crystallographic axes, which is crucial for high-performance vertical electronic components, due to imprecision in existing alignment techniques and the complexity of using X-ray diffractometry tools.
Innovation Solution
A method involving a heat treatment process to create nanometric steps on both donor and support substrates, followed by optical alignment with precision better than +/-0.1°, allowing for accurate alignment of crystallographic axes and enabling direct bonding for the transfer of a thin monocrystalline layer onto a support substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional alignment methods using flat surfaces or notches are used, then the manufacturing process is simple, but the alignment precision is insufficient (accuracy of +/-1°)
Solution Approach 1:
The patent applies preliminary action by performing heat treatment on the substrates before assembly to pre-form nanometric steps that serve as alignment references. These steps are created in advance on the donor and support substrates, enabling precise optical alignment (better than +/-0.1°) during subsequent assembly without requiring complex alignment equipment during the bonding process itself.
Solution Approach 2:
The patent replaces mechanical alignment methods (using flat surfaces or notches) with optical alignment methods. Instead of relying on mechanical features with +/-1° accuracy, the invention uses optically visible nanometric steps created by heat treatment, enabling precision better than +/-0.1° through optical microscopy or interferometry.
2Manufacturing precision
If X-ray diffractometry tools are used to achieve precise identification of crystallographic axes, then alignment precision is improved, but the manufacturing process becomes much more complex
Solution Approach 1:
The patent replaces complex X-ray diffractometry tools with simpler optical methods. The heat treatment creates nanometric steps that are directly visible and measurable using optical microscopy or interferometry, eliminating the need for expensive and complex X-ray equipment while achieving the same precision in crystallographic axis identification.
Solution Approach 2:
The patent changes the physical state and surface morphology of the substrates through heat treatment, transforming the surface to create nanometric steps. This parameter change in surface topology provides a new reference system that can be measured with simple optical tools rather than requiring complex X-ray diffraction analysis.
3Manufacturing precision
If no surface reorganization is performed, then the manufacturing process is simpler, but alignment accuracy cannot reach +/-0.1°
Solution Approach 1:
The patent applies preliminary action by performing heat treatment to create nanometric steps before the alignment and assembly operations. This pre-preparation of surface features enables the subsequent optical alignment to achieve +/-0.1° accuracy without adding complexity to the alignment process itself, as the reference features are already in place.
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 precise alignment of crystallographic axes with high accuracy, facilitating the production of composite structures suitable for high-performance vertical electronic components without the need for complex X-ray diffractometry tools, thereby improving manufacturing efficiency and component performance.
Implementation Method 1
a heat treatment step c) applied at least to the donor substrate (10), under a controlled atmosphere and at a temperature capable of causing a surface reorganization on at least one of the faces of said substrate
Data Source
Figure 1~2b
Figure 2c~2e
Figure 3~5
AI summary
The invention relates to a method for producing a composite structure comprising a thin layer of a first monocristalline material arranged on a carrier substrate. The method comprises: - a step a) of providing a donor substrate (10) consisting of the first monocristalline material and having a front face (10a) and a rear face (10b), - a step (b) of providing a carrier substrate (20) having a front face (20a), a rear face (20b), a wafer (20c) and a first alignment pattern (21) on one of the faces or on the wafer, - a step c) of heat treatment applied at least to the donor substrate (10), in a controlled atmosphere and at a temperature that is capable of causing a surface reorganisation on at least one of the faces (10a,10b) of the substrate (10), wherein the surface reorganisation gives rise to the formation of first nano-sized steps (13) parallel to a first main axis (P1), - a step d) of joining the donor substrate (10) and the carrier substrate (20), comprising, prior to bringing the substrates (10, 20) into contact, an optical alignment, to within better than +/-0.1°, between a reference mark (12) indicating the first main axis (P1) on the donor substrate (10) and at least one alignment pattern (21, 22) of the carrier substrate (20), - a step e) of transferring a thin layer (100) from the donor substrate (10) to the carrier substrate (20).