Semiconductor Substrate Bonding Layers for Water-Retained Annealing
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Solution Overview
Problem
Existing methods for bonding semiconductor substrates result in weak bonding due to the diffusion of water molecules during the bond anneal process, leading to inadequate bond strength.
Innovation Solution
The implementation of a first bonding layer with higher water diffusivity than a first barrier layer, both with controlled thicknesses, is used to retain water molecules during annealing, enhancing bond strength by forming a stronger chemical bond between the substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional bonding method is used to bond semiconductor substrates, then the bonding process is simple, but the bond strength is weak due to water molecule diffusion during annealing
Solution Approach 1:
The bonding structure is segmented into multiple functional layers: a barrier layer with low water diffusivity and a bonding layer with high water diffusivity. This segmentation allows the barrier layer to retain water molecules during annealing, preventing water loss and maintaining strong chemical bonds at the bonding interface, thereby achieving bond strength ≥2 J/m² without excessive structural complexity
Solution Approach 2:
Different regions of the bonding structure are assigned different material properties: the barrier layer uses materials with low water diffusivity (e.g., aluminum oxide, titanium oxide, hafnium oxide) to locally retain water, while the bonding layer uses materials with high water diffusivity (e.g., silicon oxide, silicon nitride) to facilitate water presence at the interface. This local quality differentiation resolves the contradiction between bond strength and structural simplicity
2Strength
If the bonding layer thickness is increased to improve bond strength, then more water can be retained, but the device complexity and processing difficulty increase
Solution Approach 1:
The patent optimizes the bonding layer thickness parameter to be ≤100 nm, which is sufficient to retain water molecules during annealing without requiring excessive thickness. This parameter optimization achieves the desired bond strength while maintaining manufacturing precision and avoiding excessive processing difficulty
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
The method results in a bond strength of greater than or equal to 2 J/m2, ensuring a robust and durable connection between semiconductor substrates.
Implementation Method 1
the second dielectric material has a higher water diffusivity than the first dielectric material
Data Source
AI summary
Methods for preparing a substrate and bonding two substrates together which include a bonding layer disposed directly over and in contact with a barrier layer in which the bonding layer has a higher water diffusivity than the barrier layer. A substrate and a bonded pair of substrates is also disclosed.