Substrate Bonding with Amorphous Layers for Low-Temperature Joining
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Solution Overview
Problem
Current bonding methods in the semiconductor industry face challenges such as high temperature requirements for heat treatment, which can lead to thermal stresses, doping diffusion issues, and difficulties in bonding metal surfaces with high oxygen affinity, especially when trying to minimize process time and material usage.
Innovation Solution
A method involving the production of amorphous layers on substrates, followed by irradiation to transform these layers into crystalline layers, allowing for a transition-free bonding process with localized heating, reduced thermal stress, and improved bond strength without the need for foreign materials or ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat treatment is applied to produce permanent fusion bond, then bonding strength is improved, but thermal stresses and process time increase
Solution Approach 1:
The patent changes the bonding mechanism from thermal (heat treatment) to mechanical/chemical (van der Waals forces during contact bonding), eliminating the need for high-temperature heat treatment while achieving permanent fusion bond. This parameter change in the bonding mechanism resolves the contradiction by decoupling bonding strength from thermal process time.
Solution Approach 2:
The patent replaces the thermal field (heat treatment) with a mechanical/physical field (contact bonding utilizing van der Waals forces), substituting the thermal bonding mechanism with a mechanical contact mechanism. This substitution eliminates thermal stresses and reduces process time while maintaining bonding strength.
2Strength
If heat treatment is applied to produce permanent fusion bond, then bonding strength is improved, but thermal stresses increase
Solution Approach 1:
The patent replaces the thermal field with a mechanical/physical contact field, eliminating the thermal stresses that harm temperature-sensitive functional units. The contact bonding mechanism achieves permanent fusion bond without the harmful thermal effects of heat treatment.
Solution Approach 2:
The patent performs contact bonding in an inert environment (without high-temperature heat treatment), creating a thermally neutral bonding process that avoids thermal stresses. The bonding occurs at ambient or controlled low temperatures, protecting temperature-sensitive components from thermal damage.
3Strength
If surface activation is applied to increase surface energy, then bonding strength at room temperature is improved, but oxide formation hinders bonding
Solution Approach 1:
The patent applies preliminary surface activation (e.g., plasma treatment, chemical etching, or mechanical polishing) to increase surface energy and remove oxides before contact bonding. This preliminary action prepares the surfaces to achieve strong van der Waals forces during contact bonding without the harmful effects of oxide formation during the bonding process itself.
Solution Approach 2:
The patent extracts or removes oxide layers from the substrate surfaces through preliminary treatment steps (such as plasma cleaning, chemical etching, or mechanical polishing) before performing contact bonding. This extraction of harmful oxides allows the surfaces to bond directly through van der Waals forces without oxide interference.
4Strength
If high temperature heat treatment is applied, then bonding strength is improved, but doping diffusion and material degradation occur
Solution Approach 1:
The patent replaces the thermal field with a mechanical/physical contact field, eliminating the high-temperature heat treatment that causes doping diffusion. Contact bonding achieves permanent fusion bond at ambient or low temperatures, preserving the original doping distribution and material properties.
Solution Approach 2:
The patent changes the bonding mechanism from thermal to mechanical/chemical, fundamentally altering the process parameters from high temperature to ambient/low temperature. This parameter change eliminates doping diffusion while maintaining bonding strength through van der Waals forces during contact bonding.
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 enables efficient, low-temperature bonding with minimized thermal stress and process time, producing a strong, transition-free substrate stack with improved electrical properties and reduced material usage, while avoiding the formation of oxides that hinder bonding.
Implementation Method 1
irradiation of the amorphous layer or the amorphous layers with radiation in such a way that the amorphous layer or the amorphous layers is/are transformed into a crystalline layer or crystalline layers
Implementation Method 2
allowing for a transition-free bonding process with localized heating, reduced thermal stress
Implementation Method 3
The fixing of the two substrates mainly takes place by van der Waals forces. The fixing is referred to as a prebond
Implementation Method 4
In order to produce a permanent fusion bond, the substrate stack undergoes a heat treatment, also referred to as annealing. The heat treatment leads to the formation of covalent bonds between the surfaces of the two substrates
Implementation Method 5
the substrate stack undergoes a heat treatment, also referred to as annealing
Data Source
AI summary
A method for bonding a first substrate with a second substrate, with the following sequence: production of a first amorphous layer on the first substrate and/or production of a second amorphous layer on the second substrate, bonding of the first substrate with the second substrate at the amorphous layer or at the amorphous layers to form a substrate stack, irradiation of the amorphous layer or the amorphous layers with radiation in such a way that the amorphous layer or the amorphous layers is/are transformed into a crystalline layer or crystalline layers.