Fluorescent Alignment Marks for Accurate Wafer Bonding
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, and reliability, particularly in the wafer bonding process, due to complexity and alignment issues during the fabrication process.
Innovation Solution
The integration of fluorescence material-based alignment marks on both wafers, which are arranged parallel and adjacent to each other, enhances optical recognition and serves as complementary references during bonding, improving the yield and reliability of semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment marks are used during wafer bonding, then the fabrication process can proceed, but optical recognition is insufficient leading to alignment errors and reduced yield
Solution Approach 1:
The patent applies fluorescence materials to alignment marks that emit specific wavelengths of light when excited. This causes the alignment marks to glow with distinct colors or brightness levels, enabling optical recognition systems to detect them with high precision during wafer bonding, thereby resolving the contradiction between measurement precision and reliability
Solution Approach 2:
The patent changes the optical parameters of alignment marks by incorporating fluorescence materials with different excitation and emission characteristics. This allows the alignment marks to be distinguished under specific wavelengths of light, improving both alignment accuracy and bonding yield through enhanced optical detectability
2Productivity
If scaling down continues to meet computing demand, then device performance improves, but alignment issues and fabrication complexity increase
Solution Approach 1:
The patent replaces conventional mechanical or geometric alignment methods with optical detection using fluorescence-based alignment marks. This substitution enables more precise alignment at scaled dimensions without proportionally increasing fabrication complexity, as the optical system can detect sub-micron features more effectively than mechanical methods
3Manufacturing precision
If alignment marks are made visible for recognition, then bonding accuracy improves, but the material options are limited to non-fluorescent materials
Solution Approach 1:
The patent uses composite materials that combine fluorescent compounds with dielectric or conductive matrices. These composite alignment marks maintain the electrical and mechanical properties needed for semiconductor fabrication while adding optical visibility through the fluorescent component, thus improving bonding accuracy without limiting material versatility
Solution Approach 2:
The fluorescence-based alignment marks serve multiple functions: they provide structural definition for alignment, enable optical detection for precision bonding, and can be integrated with various dielectric or conductive materials. This multi-functionality resolves the contradiction by expanding material selection while maintaining manufacturing precision
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
The use of fluorescence material in alignment marks improves optical recognition and bonding accuracy, leading to enhanced yield and reliability in semiconductor device fabrication.
Implementation Method 1
The plurality of first alignment marks and the plurality of second alignment marks comprise a fluorescence material
Data Source
AI summary
The present application discloses a semiconductor device having integral alignment marks with decoupling features and a method for fabricating the semiconductor device. The semiconductor device includes a substrate; a dielectric stack positioned on the substrate; two conductive features positioned in the dielectric stack; a decoupling unit positioned in the dielectric stack, between the two second conductive features, and including a bottle-shaped cross-sectional profile; and an alignment mark positioned on the decoupling unit. The alignment mark includes a fluorescence material.