SiOG Surface Irregularities via Ion Implantation and Barrier Layers
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Solution Overview
Problem
The existing methods for creating Silicon On Glass (SiOG) structures face challenges due to surface irregularities caused by the use of glass-based substrates, which require lengthy and costly chemical-mechanical polishing, and the potential harmfulness of metal components in the glass to the silicon layer.
Innovation Solution
A method involving a glass-based support substrate with a thickness between 300 μm and 600 μm, and the use of intercalated silicon nitride and oxide layers to reduce surface irregularities, along with a specific ion implantation process, to minimize the depth and density of canyons and microroughness in the transferred layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If glass-based support substrate is used to replace silicon substrate, then cost is reduced, but surface irregularities increase
Solution Approach 1:
The patent applies preliminary action by performing ion implantation (hydrogen or helium) into the source substrate before bonding to create a weakened zone. This pre-prepared separation zone enables cleaner splitting and reduces surface irregularities on the transferred layer, addressing the surface quality issue while maintaining cost benefits of glass substrates
Solution Approach 2:
The patent introduces an intermediary barrier layer (such as SiO2, Si3N4, or TiN) between the glass-based support substrate and the silicon layer. This intermediary layer protects the silicon from harmful metal components in the glass while also serving as a bonding interface, thus resolving both the contamination risk and surface irregularity issues
2Manufacturing precision
If chemical-mechanical polishing is performed to remove surface irregularities, then surface quality is improved, but time and material loss increase
Solution Approach 1:
The patent performs preliminary ion implantation and creates a controlled weakened zone before bonding and separation. This preliminary preparation ensures that the separation process generates minimal surface irregularities, significantly reducing the subsequent polishing time and material removal requirements
Solution Approach 2:
The patent changes the physical and chemical parameters of the source substrate through ion implantation, creating a modified layer with different mechanical properties. This parameter change allows for cleaner separation and reduces the amount of material that needs to be removed during polishing
3Object-affected harmful factors
If barrier layer is added between glass substrate and silicon layer, then harmful effects are reduced, but device complexity increases
Solution Approach 1:
The patent introduces a thin barrier layer (typically 1-100 nm) as an intermediary between the glass substrate and silicon layer. This layer acts as a protective mediator that prevents metal diffusion from glass to silicon while maintaining electrical isolation and bonding functionality, thus protecting against contamination without significantly increasing device complexity
Solution Approach 2:
The patent modifies the chemical composition and physical properties of the interface region by adding a barrier layer with specific material properties (such as SiO2, Si3N4, or TiN). This parameter change creates a protective interface that blocks harmful metal diffusion while maintaining compatibility with the bonding process
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 significantly reduces the surface irregularities, decreases the need for extensive polishing, conserves high-grade silicon, and enhances the quality of SiOG structures by optimizing the glass substrate thickness and using SiNx/SiO2 layers to improve the bonding interface.
Implementation Method 1
the thickness of the glass-based substrate is comprised between 300 μm and 600 μm
Implementation Method 2
The implantation leads to the creation of a buried, weakened zone 2
Implementation Method 3
one SiO2 layer may be used to obtain hydrophilic surface conditions between the glass-based support substrate 3 and the silicon layer 4
Implementation Method 4
Anodic bonding substantially removes alkali and alkali earth glass constituents and other positive modifier ions that are harmful for silicon from about 100 nm thick region in the surface of glass adjoining the bond interface
Data Source
AI summary
A method for reducing irregularities at a surface of a layer transferred from a source substrate to a glass-based support substrate, by generating a weakening zone in the source substrate; contacting the source substrate and the glass-based support substrate; and splitting the source substrate at the weakening zone; wherein the glass-based substrate has a thickness of between 300 μm and 600 μm.