Scanning Holography Substrate Alignment for Transfer Precision
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Solution Overview
Problem
Existing substrate alignment methods, particularly those using indirect positional measurements, struggle with precision and stability during transfer processes, leading to potential misalignment and process failure.
Innovation Solution
A scanning holography-based substrate alignment apparatus and method using infrared, visible, or ultraviolet wavelengths to directly measure and align substrates by capturing holographic information, reconstructing alignment marks, and adjusting positions based on coordinate differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If indirect positional measurement methods are used to align substrates, then the measurement process is simplified, but the alignment precision deteriorates
Solution Approach 1:
The patent replaces indirect mechanical positional measurement with direct optical holographic measurement. The holographic measurement system uses light interference patterns to directly capture and analyze substrate positions and alignment marks, eliminating the need for complex mechanical measurement mechanisms while achieving superior measurement precision.
Solution Approach 2:
The patent creates optical copies (holograms) of the substrates and their alignment marks. By capturing three-dimensional holographic images of the alignment marks on both substrates, the system can reconstruct and analyze their positions precisely without physically touching or disturbing the substrates, thereby maintaining both simplicity and high precision.
2Measurement precision
If substrate position is measured before transfer, then alignment information is obtained, but position instability occurs during transfer
Solution Approach 1:
The patent performs holographic measurement of substrate positions and alignment marks after the substrates are already mounted on their respective holders and positioned in the final configuration. This preliminary capture of positional data before any transfer operation ensures that the measured positions reflect the actual final positions, and any subsequent transfer can be precisely compensated based on these pre-measured coordinates.
Solution Approach 2:
The system uses the holographically measured position information as feedback to calculate and apply precise correction amounts during the transfer process. By comparing the measured positions of alignment marks on different substrates and computing the required offset, the system provides real-time feedback control that maintains alignment accuracy even when substrate positions shift during transfer.
3Measurement precision
If direct holographic measurement is used to align substrates, then alignment precision is improved, but the device complexity increases
Solution Approach 1:
The holographic measurement system is designed to perform multiple functions: it measures positions of substrates, locates alignment marks, determines relative orientations, and provides data for transfer compensation. By making the holographic system multi-functional, the patent reduces the need for separate measurement devices, thereby managing overall system complexity while maintaining high alignment 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
Enables precise alignment of substrates by directly measuring and adjusting positional differences, ensuring accurate alignment without misalignment issues during transfer.
Implementation Method 1
a holographic optical apparatus configured to obtain holographic information about substrates at different positions
Implementation Method 2
a light detection unit configured to convert light reflected or transmitted from the target object into an electrical signal
Implementation Method 3
a light source unit using any one of infrared, visible, and ultraviolet wavelengths
Implementation Method 4
a scan beam generation unit configured to branch light of a specific wavelength to generate a scan beam through interference
Data Source
AI summary
The present disclosure relates to a scanning holography-based substrate alignment apparatus and method, wherein the apparatus includes: a sample fixing unit including a plurality of holders configured to support substrates at different positions by fixing each of the substrates at both ends thereof, each of the substrates including a substrate and a chip; a sample transfer unit configured to move the substrates at the different positions supported by the plurality of holders to a specific position; a holographic information receiving unit configured to receive holographic information about the substrates at the different positions from a holographic optical apparatus; a substrate position determination unit configured to analyze the holographic information through a holographic signal processing apparatus to determine position information for the substrates at the different positions; and a substrate position re-aligning unit configured to re-align the substrates at the different positions using the position information.