Recycled Substrate Surface Recess for SMART CUT Contamination Control
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Solution Overview
Problem
The reuse of recycled donor substrates in the SMART CUT® process often results in surface contamination due to uncontrolled detachment during thermal or chemical treatments, which is attributed to the presence of contaminating regions near the implanted zones.
Innovation Solution
A method for recycling substrates with a step-like residue that involves removing material beyond the modified zone to ensure the surface of the substrate lies lower than the level of the modified zone, thereby reducing contamination and the risk of uncontrolled detachment in subsequent fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If material removal is performed only up to the level of the modified zone, then manufacturing precision is maintained, but surface contamination and uncontrolled detachment occur during subsequent thermal or chemical treatments
Solution Approach 1:
The patent extracts and removes the harmful modified zone (ion-implanted region) from the substrate surface by performing material removal beyond the modified zone level. This extraction eliminates the source of contamination that causes uncontrolled detachment during thermal or chemical treatments, thereby improving substrate reuse reliability without compromising manufacturing precision
Solution Approach 2:
The patent applies preliminary material removal to create a recess below the modified zone level before subsequent fabrication steps. This preliminary action prevents future contamination and detachment issues by eliminating the problematic modified zone in advance, ensuring reliable substrate reuse in the SMART CUT process
2Reliability
If material removal is performed beyond the modified zone, then contamination risk is reduced, but substrate thickness is reduced
Solution Approach 1:
The patent applies material removal locally only in the circumferential region where the modified zone exists, rather than uniformly across the entire substrate. This localized approach eliminates contamination risks at the edge regions while preserving the central substrate material, thereby minimizing overall substrate material loss while maintaining high reuse reliability
Solution Approach 2:
The patent creates a recess structure that copies the modified zone geometry but extends below it. By replicating the modified zone's circumferential pattern and removing material to a lower level, the solution eliminates contamination sources while maintaining the structural integrity and thickness of the central substrate region
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 effectively reduces the risk of surface contamination and uncontrolled detachment by removing contaminating regions, allowing for more efficient reuse of substrates and reducing material loss, thereby enhancing the reliability and longevity of substrate recycling.
Implementation Method 1
a material removal is carried out in the first region so that, after removal, the surface of the substrate in the first region is at least partially, in particular completely, lying lower than the level of the modified zone before material removal
Data Source
AI summary
The invention relates to a method for recycling a substrate with a step-like residue in a first region of its surface, in particular along the edge of the substrate, which protrudes with respect to the surface of a remaining second region of the substrate, and wherein the first region comprises a modified zone, in particular an ion implanted zone, essentially in a plane corresponding to the plane of the surface of the remaining second region of the substrate and/or chamfered towards the edge of the substrate. To prevent the negative impact of contaminants in subsequent laminated wafer fabricating processes, the recycling method comprises a material removal step which is carried out such that the surface of the substrate in the first region is lying lower than the level of the modified zone before the material removal. The invention also relates to a laminated wafer fabricating method using the recycled substrate and to a recycled substrate in which the surface of a first region lies lower than the surface of the second region.