Liquid-Assisted Bonding for Microdevice Electrode Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for transferring devices, such as wafer bonding, face challenges in efficiently and cost-effectively handling large-scale transfers of millions of devices, particularly in terms of time efficiency, cost reduction, and yield.
Innovation Solution
The method of liquid assisted bonding involves forming a structure with a liquid layer between an electrode and a contact pad, where hydrogen bonds are formed and then evaporated to activate surfaces for diffusion bonding, allowing for bonding at a temperature below the melting point of the materials involved, specifically using copper, titanium, tin, and indium or conductive oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional wafer bonding methods are used for transferring devices, then bonding can be achieved, but time efficiency and cost effectiveness deteriorate when handling large-scale transfers of millions of devices
Solution Approach 1:
The patent changes the bonding parameters by using liquid-assisted bonding at lower temperatures with reduced pressure, enabling faster bonding cycles that can process millions of devices efficiently while reducing overall process time
Solution Approach 2:
The patent replaces traditional mechanical wafer bonding systems with a liquid-assisted bonding mechanism that uses liquid medium to facilitate bonding, enabling parallel processing of multiple devices simultaneously and dramatically improving throughput
2Productivity
If traditional bonding methods are used, then device transfer can be completed, but manufacturing cost increases for large-scale device transfers
Solution Approach 1:
The liquid medium performs multiple functions simultaneously - it facilitates bonding, removes contaminants, and enables heat transfer - reducing the need for separate process steps and equipment, thereby lowering manufacturing costs for high-volume device transfer
Solution Approach 2:
By changing bonding parameters to lower temperatures and reduced pressure conditions, the patent reduces energy consumption and equipment requirements, making large-scale device transfer more cost-effective
3Manufacturing precision
If contact area between electrode and contact pad is reduced to <=1 square millimeter, then precision and damage prevention are improved, but bonding reliability becomes more difficult to achieve
Solution Approach 1:
The liquid medium acts as an intermediary that fills the nanoscale gap between the electrode and contact pad, ensuring complete surface contact even with small contact areas, thereby maintaining bonding reliability while achieving precise alignment
Solution Approach 2:
The patent changes the bonding mechanism to operate at the molecular level with liquid assistance, enabling reliable bonding at extremely small contact areas by enhancing surface interaction at the nanoscale
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 efficient and cost-effective bonding with a small contact area, enhancing the structural integrity and electrical contact between the electrode and contact pad, suitable for microdevices, while maintaining precision and preventing damage during the bonding process.
Implementation Method 1
hydrogen bonds are formed between the liquid layer and at least one of the electrode and the contact pad
Implementation Method 2
assist a formation of a diffusion bonding between the electrode of the device and the contact pad
Implementation Method 3
evaporating the liquid layer to break said hydrogen bonds
Data Source
AI summary
A method of liquid assisted bonding includes: forming a structure with a liquid layer between an electrode of a device and a contact pad of a substrate, and two opposite surfaces of the liquid layer being respectively in contact with the electrode and the contact pad in which hydrogen bonds are formed between the liquid layer and at least one of the electrode and the contact pad; and evaporating the liquid layer to break said hydrogen bonds such that at least one of a surface of the electrode facing the contact pad and a surface of the contact pad facing the electrode is activated so as to assist a formation of a diffusion bonding between the electrode of the device and the contact pad in which a contact area between the electrode and the contact pad is smaller than or equal to about 1 square millimeter.