Magnetic Bonding Pads for Precise Wafer Alignment
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving precise alignment and reducing misalignment during the bonding of semiconductor wafers or dies, which affects the integration density and performance of electronic components.
Innovation Solution
The use of magnetic bonding pads, which are formed on wafers and attract each other through magnetic forces, allowing for improved alignment and bonding by reducing misalignment during the bonding process, and can be electrically connected or isolated depending on the application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional bonding methods are used, then bonding process is simple, but alignment accuracy deteriorates and misalignment occurs
Solution Approach 1:
Magnetic bonding pads are introduced as intermediary elements between the bonding surfaces. These pads generate magnetic fields that act as mediators to attract and align the bonding pads of opposing wafers, thereby improving alignment accuracy without requiring complex external alignment mechanisms
Solution Approach 2:
The patent replaces mechanical alignment systems with magnetic field-based alignment. Instead of using complex mechanical positioning devices, the magnetic bonding pads generate magnetic fields that automatically guide the alignment through magnetic attraction forces, simplifying the overall bonding process while maintaining high precision
2Manufacturing precision
If magnetic bonding pads are used, then alignment accuracy improves, but device complexity increases
Solution Approach 1:
The magnetic bonding pads serve multiple functions simultaneously: they provide electrical connection, generate magnetic fields for alignment, and facilitate thermal management. This multi-functionality reduces the need for separate alignment mechanisms, thereby limiting the increase in device complexity while achieving improved alignment accuracy
Solution Approach 2:
The patent merges the alignment function with the electrical bonding function by integrating magnetic field generation capability into the bonding pads themselves. This combination eliminates the need for separate alignment systems, ensuring that the increase in device complexity is minimized while achieving superior alignment accuracy
3Productivity
If wafer bonding is performed, then integration density improves, but misalignment between wafers worsens
Solution Approach 1:
The magnetic fields generated by the bonding pads provide real-time feedback on the relative position of opposing wafers. As the wafers approach each other, the magnetic attraction strength increases, automatically guiding the wafers into proper alignment and maintaining high manufacturing precision even as integration density increases through multiple bonding layers
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 method enhances the alignment accuracy of bonded structures, reduces contact resistance, and increases the contact area, leading to improved device performance and yield, while enabling smaller device sizes and higher density.
Implementation Method 1
magnetic bonding pads, which are formed on wafers and attract each other through magnetic forces
Data Source
AI summary
A method includes forming first bonding pads over a first substrate, wherein the first bonding pads include a layer of ferromagnetic material, wherein each first bonding pad produces a respective magnetic field having a first orientation; and bonding second bonding pads to the first bonding pads using metal-to-metal bonding.