Selective Substrate Separation via Stress Corrosion

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Solution Overview

Problem

Existing methods struggle to selectively separate structures with multiple interfaces without damaging or contaminating the substrates, as they often initiate separation along the interface with the lowest fracture energy, rather than the desired one, and lack control over the separation process.

Innovation Solution

A method is developed to manufacture structures with multiple separation interfaces, where the chosen interface for stress corrosion-assisted separation is made more sensitive to corrosion by incorporating siloxane bonds, while other interfaces are made less sensitive or have higher fracture energies, allowing controlled separation by inserting a blade and applying a fluid to break siloxane bonds at the chosen interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a blade is inserted to separate substrates along an interface, then separation is achieved, but the separation may occur along the wrong interface (the one with lowest fracture energy) rather than the desired interface

Engineering Contradiction:
Improveseparation interface selectionVSAvoidseparation control
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies local quality by creating a localized zone of reduced fracture energy at the desired separation interface through ion implantation. This localized modification ensures that the separation occurs precisely at the intended interface rather than at other interfaces with naturally lower fracture energy, solving the problem of uncontrolled separation location.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-modifying the desired separation interface with ion implantation before the separation process. This advance preparation creates a predetermined weak zone that will guide the separation along the correct interface when the blade is inserted, preventing separation at incorrect interfaces.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If separation force is applied to detach substrates, then separation is achieved, but substrate surfaces may be damaged, scratched or contaminated

Engineering Contradiction:
Improveseparation processVSAvoidsubstrate surface damage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by creating a pre-weakened separation interface through ion implantation before the actual separation. This preparation allows the separation to occur along the modified interface with reduced force requirements, minimizing the risk of substrate damage, scratching, or contamination during the separation process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a modified interface layer through ion implantation that acts as a mediator between the blade and the substrate surfaces. This intermediate zone absorbs the separation stress and prevents direct contact between the blade and the substrate surfaces, thereby avoiding damage and contamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If substrates are bonded with high bonding energy, then strong adhesion is achieved, but separation becomes more difficult and may cause damage

Engineering Contradiction:
Improvebonding energyVSAvoidseparation without damage
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the bonding interface into two distinct zones: a strong bonding zone for adhesion and a weakened separation zone created by ion implantation. This segmentation allows the structure to maintain strong overall bonding while providing a specific location that is easier to separate without causing damage to the substrates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by creating a localized region of reduced fracture energy at the desired separation interface through ion implantation, while maintaining high bonding energy at other interfaces. This localized modification enables controlled separation at the intended location without compromising the overall bond strength of the structure.

Inventive Principle:
Principle #3Local quality

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 enables controlled separation along the desired interface, reducing the fracture energy of the chosen interface and maintaining the integrity of other interfaces, facilitating precise separation without damage or contamination.

Implementation Method 1

the combined action of said spreading force and of a fluid capable of breaking siloxane bonds present at said interface

Methodology Applied
Scientific EffectStress corrosion:

Data Source

PatentEP2893559B1Method for manufacturing a structure with a view to subsequent separation
Publication Date: 2020.01.08 SOITEC SA
  • EP2893559B1 patent drawingFigure 1~3
  • EP2893559B1 patent drawingFigure 4~5B
  • EP2893559B1 patent drawing

AI summary

The invention relates to a method for manufacturing a structure (S) by assembling at least two substrates (S1, S2), at least one of said two substrates being intended for being used in electronics, optics, optoelectronics and/or photovoltaics, the structure including at least two separation interfaces (I1, I2) extending parallel to the main surfaces of said structure, with a view to separating said structure (S) along an interface (I1) selected among said interfaces, said separation being carried out by inserting a blade (B) between said substrates (S1, S2) and applying a force for separating the two substrates to said blade, characterised in that said method includes the formation of the interface (I1) selected for the separation such as to be more sensitive than the other interface(s) (I2) to corrosion under stress, in other words, to the combined action of said separation force and of a fluid capable of breaking the siloxane links (Si-O-Si) provided at said interface (I1). The invention also relates to a method for separating a structure (S) capable of being obtained by said method.