Hybrid Substrate Bonding via Surface Activation Without Annealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid substrate bonding techniques, particularly hybrid wafer bonding combined with low temperature plasma-activated bonding, are limited by specific interface material restrictions and coefficient of thermal expansion mismatches, hindering the development of versatile 3D devices.
Innovation Solution
The method involves surface-activated bonding (SAB) using particle bombardment to generate dangling bonds on hybrid interface layers, allowing for bonding of diverse insulators and metals at ambient temperature without annealing, thus overcoming restrictions on substrate selection and thermal expansion mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low temperature plasma-activated bonding is used for hybrid wafer bonding, then bonding of specific interface materials (SiO2, Si3N4, Cu, W) is achieved, but substrate selection is restricted due to CTE mismatch during anneal
Solution Approach 1:
The patent changes the bonding temperature parameter from conventional high temperature (requiring anneal) to room temperature bonding. This parameter change eliminates the CTE mismatch problem that restricts substrate selection, while maintaining bond strength through surface activation by particle bombardment that creates dangling bonds for bonding
Solution Approach 2:
The patent replaces the thermal annealing process (thermal system) with particle bombardment surface activation (mechanical/physical system). This substitution creates dangling bonds on the surface that enable bonding at room temperature, eliminating the need for high temperature anneal and thus removing CTE mismatch constraints
2Reliability
If hybrid wafer bonding with annealing is used, then strong bonds are formed between specific materials, but the process is limited to specific interface materials and density rules
Solution Approach 1:
The patent changes the bonding mechanism from thermally-driven diffusion bonding to particle bombardment-induced dangling bond formation. This enables bonding of diverse materials (Ti, Pt, Pd, Al, Ag, Au with various insulators) at room temperature without requiring specific material combinations or density rules
Solution Approach 2:
The patent creates a universal bonding interface that can bond multiple metal materials (Ti, Pt, Pd, Al, Ag, Au) with multiple insulator materials (SiO2, Si3N4, SiON, SiCxNy, Al2O3, AlN, GaN, GaAs, InP) through the same particle bombardment mechanism, making the process universally applicable to various hybrid interface combinations
3Reliability
If conventional hybrid bonding is used, then bonding of metal electrodes and insulators is achieved, but metal density and patterning are restricted
Solution Approach 1:
The patent changes the bonding conditions from high temperature anneal with strict density rules to room temperature bonding with particle bombardment activation. This enables flexible metal patterning without minimum density requirements, allowing metals to be bonded directly on insulators or in various configurations without conventional restrictions
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 the bonding of substrates with varying thermal expansion coefficients and allows for flexible metal and insulator patterning, increasing the versatility of 3D device manufacturing by eliminating the need for annealing and relaxing density and patterning restrictions.
Implementation Method 1
The first hybrid interface layer and the second hybrid interface layer are surface-activated by particle bombardment. The particle bombardment is configured to remove atoms of the first hybrid interface layer and atoms of the second hybrid interface layer to generate dangling bonds
Implementation Method 2
causing the dangling bonds of the first hybrid interface layer and the dangling bonds of the second hybrid interface layer to bond together to form the first insulator to second insulator bonds and/or the first metal to second metal bonds
Data Source
AI summary
A method of manufacturing a bonded substrate stack includes: providing a first substrate having a first hybrid interface layer, the first hybrid interface layer including a first insulator and a first metal; and providing a second substrate having a second hybrid interface layer, the second hybrid interface layer including a second insulator and a second metal. The hybrid interface layers are surface-activated to generate dangling bonds on the hybrid interface layers. The surface-activated hybrid interface layers are brought into contact, such that the dangling bonds of the first hybrid interface layer and the dangling bonds of the second hybrid interface layer bond together to form first insulator to second insulator bonds and first metal to second metal bonds.