Multilayer Substrate Edge Delamination Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing processes for bonding and transferring layers in multilayer substrates often result in peripheral delamination and irregular circumferences due to low bonding energy at the edges, exacerbated by thermomechanical stresses, particularly when materials cannot withstand high temperatures, leading to contamination risks.
Innovation Solution
A process involving molecular adhesion bonding, heat treatment for consolidation, annular trimming, and chemical etching to ensure a clean edge and smooth surface, using TMAH solution for selective etching to prevent delamination and contamination, with optional grinding steps before or after trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If molecular adhesion bonding is used to bond donor and receiver substrates, then the bonding process can be implemented at low temperatures suitable for temperature-sensitive materials, but the bonding energy at the edges is insufficient leading to peripheral delamination
Solution Approach 1:
The patent applies a preliminary action by performing a first trimming step on the donor substrate before bonding to remove potential defect zones at the periphery. This preventive measure addresses the inherent weakness of molecular adhesion at edges by eliminating the problematic regions beforehand, thus preventing delamination without requiring high bonding temperatures.
2Shape
If mechanical trimming is performed on the bonded structure, then the periphery can be cleaned and regularized, but thermomechanical stresses cause localized or extended debonding of the bonding interface
Solution Approach 1:
The patent segments the trimming operation into two distinct stages: a first trimming step performed on the donor substrate before bonding to remove defect zones, and a second trimming step performed after bonding to regularize the periphery. This segmentation allows each trimming operation to be optimized independently, reducing the risk of debonding that would occur with a single aggressive trimming step on the bonded structure.
Solution Approach 2:
The first trimming step constitutes a preliminary action that prepares the donor substrate by removing potential defect zones before bonding occurs. This preliminary preparation reduces the likelihood that subsequent mechanical trimming will cause debonding, as the most vulnerable regions have already been eliminated.
3Manufacturing precision
If the donor substrate is thinned by grinding or polishing, then the transferred layer can be formed, but peripheral partial delamination occurs at the bonding interface
Solution Approach 1:
The patent performs preliminary trimming of the donor substrate before bonding to remove defect zones at the periphery. This preliminary action prevents the initiation of delamination during subsequent thinning operations, allowing the donor substrate to be thinned by grinding or polishing without causing peripheral partial delamination of the transferred layer.
4Ease of manufacture
If chamfers are present on donor and receiver substrates, then the substrates can be commonly available and easy to manufacture, but bonding energy around the edges is reduced leading to poor adhesion
Solution Approach 1:
The patent extracts or removes the problematic peripheral regions with chamfers from the bonding interface through trimming operations. By removing these defect-prone zones before and after bonding, the negative effect of chamfers on edge adhesion is eliminated, allowing the use of commonly available substrates with chamfers without compromising bonding reliability.
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 process prevents flaking and delamination, achieving a transferred layer with a regular circumference, reducing contamination risks and operational complexity while being cost-effective and applicable to temperature-sensitive materials.
Implementation Method 1
two substrates, respectively referred to as a 'donor substrate' and a 'receiver substrate,' are bonded to one another by molecular adhesion
Implementation Method 2
applying heat treatment to the aforementioned stack in order to consolidate the bonding interface
Implementation Method 3
carrying out a chemical etching step of the exposed surface of the remaining part of the donor substrate and of an exposed surface of the receiver substrate
Data Source
AI summary
A method of fabricating a multilayer substrate may include bonding a front face of a donor substrate to a front face of a receiver substrate by molecular adhesion to form a stack and applying a heat treatment to the stack to consolidate a bond interface between the donor substrate and the receiver substrate. The method may further include thinning a back face of the donor substrate, trimming a periphery of the donor substrate and at least a portion of a periphery of the receiver substrate, and etching the back face of the donor substrate, the periphery of the donor substrate, and the at least a portion of the periphery of the receiver substrate subsequent to thinning the back face of the donor substrate and trimming the periphery of the donor substrate and the at least a portion of the periphery of the receiver substrate.