Thin-Layer Transfer on Charge-Trapping Substrates Without Polishing
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Solution Overview
Problem
Existing methods for forming a charge-trapping layer on silicon-on-insulator (SOI) substrates result in surface roughness, deformation, and handling issues due to the formation of thick dielectric layers, which complicates the production process and affects the performance of electronic and photonic devices.
Innovation Solution
A process involving the simultaneous deposition and ion sputtering of a dielectric layer on a charge-trapping layer, combined with a bow compensation layer, to form a smooth and deformable carrier substrate suitable for molecular bonding, without the need for polishing, using HDP CVD and controlled parameters to achieve low surface roughness and minimal deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick dielectric layer is formed by oxidizing the charge-trapping layer, then the electromagnetic coupling prevention is improved, but the surface roughness increases and the substrate deforms
Solution Approach 1:
The patent changes the formation method parameters by using HDP CVD deposition instead of thermal oxidation, and by implementing ion sputtering to modify the dielectric layer properties. This results in a smoother surface and reduced substrate deformation while maintaining the required thickness for electromagnetic coupling prevention.
Solution Approach 2:
The patent replaces the chemical oxidation process with a physical deposition process (HDP CVD) followed by ion sputtering. This substitution of the formation mechanism allows better control over surface quality and reduces the mechanical stress that causes substrate bowing.
2Reliability
If a thick dielectric layer is formed by oxidizing the charge-trapping layer, then the electromagnetic coupling prevention is improved, but the substrate deformation increases
Solution Approach 1:
The patent modifies the dielectric layer formation parameters by using HDP CVD deposition with controlled temperature and pressure, followed by ion sputtering. This results in reduced internal stress and minimal substrate bowing while achieving the required thickness for electromagnetic coupling prevention.
Solution Approach 2:
The patent replaces the high-temperature oxidation process with HDP CVD deposition and ion sputtering, which occur at lower temperatures and generate less thermal stress, thereby reducing substrate deformation.
3Reliability
If a thick dielectric layer is formed by deposition, then the electromagnetic coupling prevention is improved, but the surface roughness increases
Solution Approach 1:
The patent uses HDP CVD deposition with specific parameters (pressure, temperature, gas flow rates) to achieve smooth surface morphology. The subsequent ion sputtering further smooths the surface by removing protrusions and filling valleys, resulting in low surface roughness despite the thick layer thickness.
Solution Approach 2:
The patent employs ion sputtering as a post-deposition treatment to mechanically smooth the surface. The ion bombardment selectively removes material from high points and redistributes it, achieving a smoother surface without requiring additional polishing steps.
4Ease of manufacture
If ion implantation is used to create a weakened plane, then the layer transfer is enabled, but the process complexity increases with thick dielectric layers
Solution Approach 1:
The patent forms the complete dielectric layer on the carrier substrate before performing ion implantation to create the weakened plane. This preliminary formation of the dielectric layer simplifies the overall process by eliminating the need for subsequent polishing steps that would be required if the dielectric layer were formed after transfer.
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
The process results in a carrier substrate with low surface roughness and reduced deformation, facilitating molecular bonding and simplifying the production process, while maintaining the integrity of the substrate for electronic and photonic devices.
Implementation Method 1
simultaneous deposition and ion sputtering of a dielectric layer
Implementation Method 2
simultaneous deposition and ion sputtering of a dielectric layer
Implementation Method 3
The weakened plane is obtained by introducing light species (hydrogen and/or helium, for example) into the donor substrate, through the dielectric layer when present, generally by implantation
Implementation Method 4
the formation of a dielectric layer by oxidizing either or both of these substrates
Data Source
AI summary
A method for transferring a thin layer onto a carrier substrate comprises preparing a carrier substrate using a preparation method involving supplying a base substrate having, on a main face, a charge-trapping layer and forming a dielectric layer having a thickness greater than 200 nm on the charge-trapping layer. Once the dielectric layer is formed, the ionized deposition and sputtering of the dielectric layer are simultaneously performed. The transfer method also comprises assembling, by way of molecular adhesion and with an unpolished free face of the dielectric layer, a donor substrate to the dielectric layer of the carrier substrate, the donor substrate having an embrittlement plane defining the thin layer. Finally, the method comprises splitting the donor substrate at the embrittlement plane to release the thin layer and to transfer it onto the carrier substrate.