Thin-Layer Transfer on Charge-Trap Substrates With Low Curvature
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Solution Overview
Problem
The formation of a dielectric layer by oxidation or conventional deposition techniques on silicon-on-insulator (SOI) substrates results in a rough surface state and significant curvature, complicating the assembly process and affecting the functionality of electronic and photonic devices, particularly in the field of photonics.
Innovation Solution
A method involving the simultaneous deposition and ionic sputtering of a dielectric layer on a support substrate with a charge trapping layer, forming a smooth and thick dielectric layer without the need for polishing, and optionally incorporating a curvature compensation layer to manage substrate deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dielectric layer is formed by oxidation or conventional deposition on a support substrate, then the dielectric layer can be formed with sufficient thickness, but the surface becomes rough and significant curvature is generated
Solution Approach 1:
The patent changes the formation parameters of the dielectric layer by using atomic layer deposition (ALD) instead of conventional deposition or oxidation. ALD allows precise control of deposition parameters to achieve smooth surfaces at thicknesses greater than 200nm without the roughness and curvature problems of other methods. The process parameters including temperature, pressure, and precursor flow rates are optimized to maintain surface quality throughout the deposition sequence.
Solution Approach 2:
The patent introduces an intermediary polishing step using chemical mechanical polishing (CMP) between dielectric layer formation and molecular adhesion assembly. This intermediary process removes the surface roughness and curvature defects generated during dielectric layer formation, providing a smooth surface for subsequent assembly without compromising the structural integrity or thickness of the dielectric layer.
2Reliability
If a thick dielectric layer is formed to prevent electromagnetic coupling, then electromagnetic shielding is improved, but substrate curvature increases making handling difficult
Solution Approach 1:
The patent changes the deposition method parameters to ALD, which provides superior control over stress accumulation during thick dielectric layer formation. By controlling deposition temperature, pressure, and cycle parameters, the patent achieves thick layers (>200nm) with minimal induced curvature, maintaining substrate flatness for easy handling while ensuring effective electromagnetic shielding between the support substrate and thin layer.
Solution Approach 2:
The patent introduces curvature compensation as an intermediary corrective step. After forming the thick dielectric layer, a curvature compensation layer is deposited on the opposite side of the substrate to balance the stress-induced curvature. This intermediary action restores substrate flatness, enabling easy handling and molecular adhesion assembly while preserving the electromagnetic shielding function of the thick dielectric layer.
3Productivity
If conventional deposition techniques are used to form a dielectric layer, then the layer can be formed quickly, but the surface roughness increases requiring additional polishing
Solution Approach 1:
The patent introduces chemical mechanical polishing (CMP) as an intermediary step between dielectric layer formation and molecular adhesion assembly. This polishing step efficiently removes surface roughness generated during rapid conventional deposition, restoring surface smoothness without significantly extending the overall process time. The CMP process acts as a mediator that decouples the trade-off between deposition speed and surface quality, allowing both high productivity and manufacturing precision to be achieved.
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 results in a smooth dielectric layer with reduced substrate curvature, facilitating molecular adhesion assembly and improving the surface quality for device manufacturing, enhancing the performance and handling of SOI substrates in both RF and photonic applications.
Implementation Method 1
the formation of the dielectric layer simultaneously implementing the deposition and ion sputtering of the dielectric layer
Implementation Method 2
the formation of the dielectric layer simultaneously implementing the deposition and ion sputtering of the dielectric layer
Implementation Method 3
assembling, by molecular adhesion and without preparing the free face of the dielectric layer by polishing, a donor substrate to the dielectric layer
Data Source
Figure 1~2
Figure 3A~3C
Figure 3D~4
AI summary
The invention relates to a method for transferring a thin layer (5) onto a support substrate (1) comprising preparing a support substrate (1) using a preparation method comprising supplying a base substrate (3) having, on a main face, a charge trapping layer (2) and forming a dielectric layer (4) having a thickness greater than 200 nm on the charge trapping layer (2). Once the dielectric layer (4) is formed, the ionised deposition and sputtering of the dielectric layer are simultaneously performed. The transfer method also comprises assembling, by means of molecular adhesion and with an unpolished free face of the dielectric layer (4), a donor substrate to the dielectric layer (4) of the support substrate (1), the donor substrate having an embrittlement plane defining the thin layer (5). Finally, the method comprises breaking the donor substrate at the embrittlement plane in order to release the thin layer (5) and to transfer it onto the support substrate (1).