Lithography Alignment Registration With Real-Time Mark Measurement
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Solution Overview
Problem
Current Direct Imaging (DI) and Laser Direct Imaging (LDI) lithography systems face limitations in throughput due to time-consuming registration and measurement of reference points, especially when high accuracy and small feature sizes are required, leading to increased processing time and cost.
Innovation Solution
A device and method that integrates a light source, light modulator, measurement system, and control unit with concurrent optical paths to measure alignment marks in real time during lithographic printing, allowing for simultaneous exposure and measurement, reducing the need for separate measurement equipment and calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate measurement equipment and procedures are used for registering reference points, then measurement accuracy can be achieved, but system complexity increases and throughput decreases
Solution Approach 1:
The patent combines the measurement system and exposure system into a single integrated lithography apparatus. The measurement system includes a measurement beam source and detector, while the exposure system includes an exposure beam source and modulator. Both systems share common optical components and are controlled by a unified control unit, eliminating the need for separate measurement equipment and reducing system complexity while maintaining measurement accuracy.
Solution Approach 2:
The control unit serves multiple functions: it controls both the measurement beam (steering, timing) and the exposure beam (modulation, timing), and processes data from both measurement and exposure operations. This multi-functional control architecture reduces the number of separate control systems needed, thereby reducing overall system complexity while maintaining precise measurement capabilities.
2Measurement precision
If separate measurement and exposure procedures are used, then measurement accuracy is maintained, but processing time increases
Solution Approach 1:
The patent enables continuous operation by allowing measurement and exposure to occur in an integrated workflow. The control unit coordinates the measurement beam and exposure beam operations so that measurement data is collected and processed continuously, and exposure operations proceed without interruption. This eliminates the sequential bottleneck where the system must complete measurement before starting exposure, thereby reducing total processing time while maintaining measurement accuracy.
Solution Approach 2:
The measurement system operates in advance of the exposure operation to determine the precise positions of alignment marks and reference points. The control unit uses this pre-acquired measurement data to calculate transformation parameters (translation, rotation, scaling) before the exposure beam is activated. This preliminary measurement and calculation phase allows the exposure operation to proceed immediately with accurate positioning information, reducing overall processing time.
3Manufacturing precision
If high number of reference points are measured for fine line lithography, then pattern accuracy improves, but measurement time increases
Solution Approach 1:
The patent replaces mechanical measurement systems with an optical-based measurement system. The measurement beam (optical) detects alignment marks and reference points non-contactly, eliminating mechanical scanning and positioning mechanisms. This optical measurement approach significantly reduces measurement time while maintaining high precision, enabling the measurement of a large number of reference points required for fine line lithography without proportionally increasing measurement time.
Solution Approach 2:
The control unit dynamically adjusts measurement parameters such as beam steering angles, detector positioning, and measurement timing based on the specific requirements of fine line lithography. By optimizing these parameters, the system achieves high measurement precision for numerous reference points while minimizing measurement time, thereby resolving the contradiction between pattern accuracy and measurement time.
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 faster and more accurate registration and position calculation, significantly reducing the time consumption of high-accuracy measurements and improving the throughput of fine line lithography processes.
Implementation Method 1
a light source providing an exposure beam, a light modulator modulating the exposure beam according to an exposure pattern
Implementation Method 2
a measurement system incorporated in the exposure apparatus and is configured to measure a position of a number of alignment marks
Data Source
AI summary
A device for measuring reference points in real time during lithographic printing includes a light source providing an exposure beam; a light modulator modulating the exposure beam according to an exposure pattern; a measurement system configured to measure a position of a number of alignment marks previously arranged on a substrate; and an exposure optical system comprising a control unit. The exposure optical system delivers the modulated exposure beam as an image provided by the light modulator onto the substrate. The exposure system control unit is configured to calculate the orientation of the substrate based on the position of the alignment marks and control the delivering of the modulated exposure beam relative to the calculated orientation of the substrate.