Donor Substrate Edge Masking to Reduce Annealing Particles
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Solution Overview
Problem
The existing methods for producing semiconductor-on-insulator (SeOI) substrates through the SmartCut process result in significant particle formation during the detachment of the carrier substrate from the donor substrate, leading to inefficiencies and resource wastage due to the need for extensive cleaning processes.
Innovation Solution
A process is developed where a predetermined separation zone is created on the edge of the donor substrate with a lower ion implantation dose compared to the central zone, using a chamfered edge and controlled ion implantation techniques to minimize blister formation and particle creation during thermal annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion implantation is carried out on the entire surface of the donor substrate including the edge zone, then the separation zone is effectively created for layer transfer, but particle formation and blistering increase during thermal annealing
Solution Approach 1:
The patent applies local quality by creating a chamfered zone at the edge of the donor substrate with different geometric properties (slanted surface) compared to the central zone. This local geometric modification prevents ion implantation in the edge zone while maintaining implantation in the central zone, thereby eliminating particle formation at edges without compromising separation zone effectiveness in the center.
Solution Approach 2:
The patent segments the donor substrate surface into two distinct zones: a chamfered edge zone and a flat central zone. This segmentation allows differential ion implantation treatment, where only the central zone receives full implantation dose, while the edge zone is protected by the chamfered geometry. The segmentation resolves the contradiction by spatially separating the functions of separation zone creation and particle minimization.
2Object-generated harmful factors
If the donor substrate edge is left unbonded to the carrier substrate, then blister formation is reduced, but the separation zone effectiveness may be compromised
Solution Approach 1:
The chamfered zone creates a local geometric difference at the substrate edge, forming a physical barrier that prevents bonding between the donor substrate edge and carrier substrate. This local unbonded condition eliminates the stiffening effect at edges, reducing blister formation during thermal annealing while the central bonded zone maintains separation zone effectiveness for layer transfer.
3Object-affected harmful factors
If RCA cleaning processes are applied to remove particles from the SeOI substrate, then particle contamination is reduced, but processing time and resource consumption increase
Solution Approach 1:
The patent performs preliminary action by creating the chamfered zone before ion implantation, which pre-prevents particle formation at the substrate edges. By addressing the root cause of particle generation through geometric modification prior to implantation, the need for subsequent extensive RCA cleaning processes is eliminated, thereby reducing processing time and resource consumption while maintaining low particle contamination.
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 reduces particle formation and blistering during the detachment process, allowing for more efficient layer transfer with fewer particles on both the transferred layer and the remaining donor substrate, thereby optimizing the SeOI substrate fabrication process.
Implementation Method 1
ion implantation, during a thermal annealing
Implementation Method 2
thermal annealing
Implementation Method 3
propagating a fracture wave along an interface in the donor substrate
Data Source
Figure 1A~1F
Figure 2A~2C
Figure 3A~3B
AI summary
The invention relates to a process for forming a predetermined separation zone (19) inside a donor substrate (1), in particular to be used in a process of transferring a layer onto a carrier substrate. This process comprises an implantation step (17) that is carried out such that the implantation dose (25) in a zone of the edge (5) of the donor substrate (1) is lower than the implantation dose (27) in a central zone (9) of the donor substrate (1) to limit the formation of particles during thermal annealing. The invention also relates to a donor substrate (1) for a process of transferring a thin layer onto a carrier substrate produced by means of the process described above. The invention also relates to a device for limiting an implantation region to a zone of the edge (5) of a donor substrate (1).