Magnetic Cross Alignment Marks for Low-Misalignment Wafer Bonding
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving precise alignment and reducing misalignment between stacked semiconductor wafers during bonding, which affects the integration density and performance of semiconductor devices.
Innovation Solution
The use of magnetic alignment marks with opposite magnetic polarity on wafers allows for magnetic self-alignment during bonding, combining optical and magnetic alignment processes to enhance accuracy and reduce misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional optical alignment processes are used for wafer bonding, then the alignment process is simple and fast, but the alignment precision is insufficient leading to misalignment between stacked wafers
Solution Approach 1:
Magnetic alignment marks are introduced as an intermediary element between the optical alignment system and the wafers. These marks generate magnetic fields that interact with each other to provide additional alignment forces, enhancing the precision of the optical alignment process without requiring a complete overhaul of the existing system
Solution Approach 2:
The patent replaces purely optical alignment with a hybrid system that incorporates magnetic field interactions. The magnetic alignment marks generate magnetic forces that supplement optical alignment, transitioning from a purely optical/mechanical system to one that utilizes magnetic field effects for enhanced precision
2Manufacturing precision
If magnetic alignment marks with opposite magnetic polarity are used, then the alignment accuracy is improved through magnetic self-alignment, but the manufacturing process complexity increases
Solution Approach 1:
The magnetic alignment marks are designed to automatically self-align through magnetic attraction between opposite polarities. During the bonding process, the marks with opposite magnetic polarity naturally attract and align themselves, eliminating the need for complex external alignment mechanisms or additional manual adjustment steps
Solution Approach 2:
The magnetic alignment marks are pre-formed on the wafers before bonding with predetermined opposite magnetic polarities. This preliminary configuration ensures that when the wafers are brought together, the magnetic attraction immediately engages to provide self-alignment, reducing the complexity of the actual bonding process
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 improves the alignment accuracy between wafers, resulting in reduced misalignment and improved bonding quality, leading to enhanced integration density and device performance.
Implementation Method 1
magnetic alignment marks with opposite magnetic polarity on wafers allows for magnetic self-alignment during bonding
Data Source
AI summary
In an embodiment, a structure includes: a first device including a first dielectric layer and a first alignment mark in the first dielectric layer, the first alignment mark including a first magnetic cross, the first magnetic cross having a first north pole and a first south pole; and a second device including a second dielectric layer and a second alignment mark in the second dielectric layer, the second alignment mark including a second magnetic cross, the second magnetic cross having a second north pole and a second south pole, the first north pole aligned with the second south pole, the first south pole aligned with the second north pole, the first dielectric layer bonded to the second dielectric layer by dielectric-to-dielectric bonds, the first alignment mark bonded to the second alignment mark by metal-to-metal bonds.