Amorphous Interlayer Bonding Silicon Lithium Tantalate
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Solution Overview
Problem
The bonding strength between silicon and lithium tantalate substrates is low when subjected to surface activation, leading to peeling during processing, despite the presence of a tantalum-rich amorphous layer which should enhance bonding.
Innovation Solution
An amorphous layer with a higher concentration of metal elements such as niobium and tantalum, exceeding the concentration of oxygen, is introduced between the substrates to improve bonding strength, achieved by surface activation and controlled element diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If surface activation is performed on silicon and lithium tantalate substrates, then bonding can be achieved at relatively low temperature, but the bonding strength is low and peeling occurs during processing
Solution Approach 1:
The invention changes the compositional parameters of the amorphous layer by controlling the concentration of metal elements (niobium and tantalum) to be higher than oxygen concentration (20-65 atom %), transforming the layer from an oxygen-rich state that causes weak bonding to a metal-rich state that provides strong bonding through enhanced interfacial adhesion
Solution Approach 2:
The invention creates a composite amorphous layer structure combining metal elements (niobium/tantalum) with oxygen in specific proportions, forming a composite material with optimized bonding characteristics that overcomes the limitations of simple oxide layers while maintaining low-temperature processing capability
2Strength
If tantalum element is diffused into the amorphous layer, then bonding strength should be high, but peeling still occurs during polishing or processing
Solution Approach 1:
The invention changes the concentration parameter of metal elements in the amorphous layer to exceed oxygen concentration (20-65 atom %), creating a metal-rich environment that prevents excessive tantalum diffusion while maintaining high bonding strength, thereby eliminating peeling during processing
Solution Approach 2:
The amorphous layer acts as an intermediary between the silicon substrate and lithium tantalate substrate, with controlled metal element concentration that mediates the bonding interface to prevent excessive diffusion of tantalum while ensuring strong adhesion and resistance to peeling during subsequent processing
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 enhanced amorphous layer significantly increases the bonding strength between the silicon and lithium tantalate substrates, preventing peeling during processing and improving the reliability of the bonded body.
Implementation Method 1
achieved by surface activation and controlled element diffusion
Implementation Method 2
achieved by surface activation and controlled element diffusion
Data Source
AI summary
A bonded body includes a supporting substrate, a piezoelectric material substrate composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate, and an amorphous layer present between the supporting substrate and piezoelectric material substrate. The amorphous layer contains one or more metal element selected from the group consisting of niobium and tantalum, an element constituting the supporting substrate and oxygen element. The concentration of the metal element in the amorphous layer is higher than the concentration of oxygen element and 20 to 65 atom %.