Donor Substrate Reclaiming via Chamfer Etching
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Solution Overview
Problem
The existing reclaiming process for donor substrates in the Smart Cut ™ process requires double-sided polishing, which removes significant material and is costly, and involves complex steps that can lead to particle contamination and reduced substrate quality.
Innovation Solution
A method that etches the chamfered regions of the donor substrate before detachment, removing the dielectric and implanted regions, thereby eliminating the need for double-sided polishing and allowing for simpler reuse of the substrate with reduced material loss and improved quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double-sided polishing is applied to reclaim the donor substrate, then the surface roughness is improved and the substrate can be reused, but significant material is removed and the process becomes costly and complex
Solution Approach 1:
The patent applies preliminary etching to the chamfered regions of the donor substrate before the layer transfer process. This pre-removal of material from the edge regions prevents the formation of protruding residues that would otherwise require extensive polishing later, thereby reducing the material loss associated with reclaiming the substrate.
Solution Approach 2:
The patent extracts and removes the problematic chamfered regions containing implanted ions and dielectric layers through etching before the transfer process. By taking out these problematic regions in advance, the need for aggressive polishing to remove protruding residues is eliminated, thus preserving substrate material.
2Manufacturing precision
If double-sided polishing is applied to reclaim the donor substrate, then the surface quality is improved, but the process complexity increases and particle contamination risk rises
Solution Approach 1:
The etching step is performed as a preliminary action before the layer transfer and before any polishing is needed. This pre-treatment of the chamfered regions simplifies the subsequent reclaiming process by eliminating the need for complex double-sided polishing operations, thereby reducing process complexity and particle contamination risk.
3Shape
If the chamfered regions with implanted ions are not removed, then the substrate geometry is maintained, but particle contamination occurs during thermal treatment due to exfoliation
Solution Approach 1:
The patent performs preliminary etching of the chamfered regions containing implanted ions before the thermal treatment step. By removing these problematic regions in advance, the source of potential particle contamination through exfoliation is eliminated, while the main substrate geometry is preserved through selective etching that spares the central regions.
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 reclaiming process, reduces material removal by up to 90%, prevents particle contamination, and allows for more frequent reuse of the donor substrate with maintained geometry and surface quality, achieving a more economic and efficient recycling process.
Implementation Method 1
the source substrate 103 is attached to the handle substrate 101, in particular via bonding taking advantage of Van der Waal's forces
Implementation Method 2
an ion implantation step, during which ions like hydrogen or rare gas ions (He, Ar, ..) are implanted into the donor substrate 103
Implementation Method 3
the donor substrate 103 is typically oxidized 105 to later on form the buried oxide layer (BOX) of the SOI structure
Data Source
Figure 1a~1c
Figure 2a~2d
Figure 3a~3e
AI summary
The invention relates to a method for transferring a layer from a donor substrate onto a handle substrate wherein, after detachment, the remainder of the donor substrate is reused. To get rid of undesired protruding edge regions which are due to the chamfered geometry of the substrates, the invention proposes to carry out an additional etching process before detachment occurs.