Microstructured Metal Hybrid Bonding for Low-Temperature Annealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The microelectronics industry faces challenges in improving yield, reducing cost, and minimizing thermal budget consumption in hybrid bonding processes, particularly in achieving lower annealing temperatures and shorter annealing durations for direct conductor-to-conductor bonding.
Innovation Solution
The implementation of microstructures, such as nanograins, on conductive features to facilitate bonding at lower temperatures, involving processes like oxidation and reduction of metal surfaces to create metal oxide layers and subsequent transformation into metal nanograins, which reduce the bonding temperature and enhance diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hybrid bonding annealing processes are used, then reliable conductor-to-conductor bonding is achieved, but high thermal budget consumption and long annealing duration occur
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical state of the conductor surface through oxidation and reduction processes. The conductor surface is oxidized to form metal oxide, then reduced to create metal grains with nanoscale dimensions. This parameter transformation enables bonding at lower temperatures (reducing thermal budget) while maintaining bonding reliability, as the nanoscale metal grains provide enhanced diffusion pathways and larger surface area for bond formation
Solution Approach 2:
The patent utilizes phase transitions by transforming the conductor surface through oxidation (metal to metal oxide) and reduction (metal oxide to metal grains). These phase transitions fundamentally alter the surface properties, creating a nanoscale grain structure that enables low-temperature bonding. The phase transition from bulk metal to nanoscale metal grains increases surface area and creates high-energy sites that facilitate diffusion and bonding at reduced thermal budgets
2Reliability
If traditional hybrid bonding annealing processes are used, then reliable conductor-to-conductor bonding is achieved, but long annealing duration is required
Solution Approach 1:
The patent changes the physical parameters of the conductor surface by creating nanoscale metal grains through oxidation-reduction cycles. This parameter change reduces the annealing duration required because the nanoscale grains provide extensive surface area and high-energy interfaces that accelerate diffusion processes. The increased surface-to-volume ratio of nanograins enables faster bond formation compared to conventional bulk metal surfaces, reducing the time required to achieve reliable bonding
3Ease of manufacture
If conventional bonding surfaces are used, then standard bonding processes are applied, but high annealing temperature is required
Solution Approach 1:
The patent applies preliminary action by performing oxidation and reduction treatments on the conductor surfaces before the actual bonding process. These preliminary treatments transform the surface morphology into nanoscale metal grains, which are then ready for low-temperature bonding. By preparing the surface in advance with these chemical treatments, the subsequent bonding step can proceed at lower temperatures without compromising bond strength, effectively decoupling surface preparation from the thermal bonding step
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 high-quality direct bonding at lower annealing temperatures, resulting in high yield and low electrical resistance, while reducing thermal stress and cost associated with traditional bonding methods.
Implementation Method 1
involving processes like oxidation and reduction of metal surfaces to create metal oxide layers
Implementation Method 2
involving processes like oxidation and reduction of metal surfaces to create metal oxide layers and subsequent transformation into metal nanograins
Implementation Method 3
which reduce the bonding temperature and enhance diffusion
Data Source
AI summary
A semiconductor element is provided with a micro-structured metal layer over conductive features of a hybrid bonding surface. The micro-structured metal layer comprises fine metal grain microstructure, such as nanograins. The micro-structured metal layer can be formed over the conductive features by providing a metal oxide and reducing the metal oxide to metal. The micro-structured metal layer can be formed selectively if the metal oxide is formed by oxidation. When directly bonded to another element, the micro-structured metal layer forming strong bonds at the bonding interface can substantially reduce annealing temperature.