Exposure Apparatus Alignment Sensor Defocus Compensation
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Solution Overview
Problem
In semiconductor manufacturing, defocus and tilt errors during alignment and focusing measurements lead to significant degradation of alignment accuracy and yield in large-sized LCD display production, as existing technologies struggle to effectively compensate for these errors.
Innovation Solution
An exposure apparatus and method utilizing a combination of alignment sensors and focusing sensors, where each alignment sensor corresponds to a focusing sensor, allowing for simultaneous detection of alignment and focusing information, enabling defocus and tilt error compensation by calculating and correcting errors based on recorded data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment and focusing measurement methods are used, then the measurement process is simple, but defocus and tilt errors occur leading to poor alignment accuracy
Solution Approach 1:
The patent combines alignment sensors and focusing sensors into a coordinated measurement system where alignment sensors detect alignment mark positions and focusing sensors detect substrate surface height, merging their data to calculate and compensate for both defocus and tilt errors simultaneously, thereby improving alignment accuracy without excessive complexity
Solution Approach 2:
The patent implements a feedback mechanism where the measured alignment and focusing information is used to calculate defocus and tilt errors, which then feed back to correct the alignment measurements, creating a closed-loop system that continuously improves measurement precision
2Measurement precision
If multiple sensors are used to improve measurement accuracy, then alignment accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The patent designs the sensor system with multi-functionality where alignment sensors serve dual purposes: detecting alignment mark positions for alignment measurement and providing positional data for tilt error calculation, while focusing sensors detect substrate height for both defocus correction and tilt compensation, reducing the need for separate dedicated sensors for each function
3Manufacturing precision
If defocus and tilt error compensation is implemented, then alignment accuracy improves, but the measurement and calculation process becomes more complex
Solution Approach 1:
The patent performs preliminary measurement of substrate surface height using focusing sensors before the main alignment exposure process, calculates the expected defocus and tilt errors in advance, and applies correction factors to the alignment measurements, thereby preparing the compensation data beforehand to simplify the real-time exposure 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 approach significantly improves alignment accuracy and production yield by eliminating defocus and tilt errors, achieving a 30 nm improvement in alignment precision.
Implementation Method 1
a plurality of first sensors arranged in a first direction and configured to detect a plurality of alignment marks on a substrate so as to obtain alignment information of the substrate
Implementation Method 2
a plurality of first sensors arranged in a first direction and configured to detect a plurality of alignment marks on a substrate
Implementation Method 3
a plurality of second sensors configured to detect focusing information of the substrate
Data Source
AI summary
In an exposure apparatus and a method for defocus and tilt error compensation, each of alignment sensors (500a, 500b, 500c, 500d, 500e, 500f) corresponds to and has the same coordinate in the first direction as a respective one of focusing sensors (600a, 600b, 600c, 600d, 600e, 600f), so that each of the alignment sensors (500a, 500b, 500c, 500d, 500e, 500f) is arranged on the same straight line as a respective one of the focusing sensors (600a, 600b, 600c, 600d, 600e, 600f). As such, alignment marks can be characterized with both focusing information and alignment information. This enables the correction of errors in the alignment information and thus achieves defocus and tilt error compensation, resulting in significant improvements in alignment accuracy and the production yield.