Stage Acceleration Control for Reticle Positioning Stability
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Solution Overview
Problem
In exposure apparatuses used for semiconductor device manufacturing and display production, positional fluctuations of the original (reticle) occur due to inertia forces during stage driving, leading to an incomplete holding state and errors in positioning, which affects the accuracy of pattern transfer onto substrates.
Innovation Solution
The exposure method involves performing a first step of scan-driving the stage at a lower maximum acceleration and a second step at a higher maximum acceleration during exposure, with the initial acceleration being lower than the subsequent acceleration to improve the holding state and reduce positional fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stage is scan-driven at high acceleration to improve productivity, then the exposure speed increases, but the original experiences positional fluctuation due to inertia forces
Solution Approach 1:
The patent applies preliminary action by performing a preliminary scan-drive at maximum acceleration before the actual exposure scan-drive. This preliminary drive pre-positions the original and improves the holding state between the original and stage, preventing positional fluctuation during the subsequent high-speed exposure process. The preliminary action prepares the system to withstand the inertia forces that will occur during high-speed operation.
Solution Approach 2:
The patent segments the scan-drive process into two distinct steps: a preliminary scan-drive step and an actual exposure scan-drive step. Each step serves a different function - the preliminary step focuses on stabilizing the original position, while the exposure step focuses on high-speed pattern transfer. This segmentation allows optimization of each step independently.
2Manufacturing precision
If the stage is scan-driven at low acceleration to reduce positional fluctuation, then positioning accuracy improves, but exposure speed decreases
Solution Approach 1:
The patent uses preliminary action to perform a preparatory scan-drive at low acceleration to stabilize the original position and improve the holding state. This preliminary stabilization allows the subsequent exposure scan-drive to operate at high acceleration without suffering from positional fluctuation, thus achieving both accuracy and speed.
3Reliability
If preliminary driving is performed at maximum acceleration to fix the original onto the stage, then the holding state improves, but the error between the fixed position and target position increases
Solution Approach 1:
The patent applies preliminary action by performing a preliminary scan-drive that focuses solely on improving the holding state without concern for positioning precision. The position correction is then applied as a separate compensatory action, decoupling the holding state improvement from the positioning accuracy requirement.
Solution Approach 2:
The patent changes the acceleration parameter between the preliminary scan-drive and the actual exposure scan-drive. The preliminary drive uses maximum acceleration to improve holding state, while the exposure drive uses adjusted acceleration and position correction to achieve both good holding state and high positioning accuracy.
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 effectively reduces positional deviations and improves the holding state of the original onto the stage, enhancing the accuracy of pattern transfer and throughput by stabilizing the original's position, thereby minimizing errors and improving the overall manufacturing process.
Implementation Method 1
exposing a substrate via an original held by a stage while scanning the original
Data Source
AI summary
The present invention provides an exposure method of exposing a substrate via an original held by a stage while scanning the original, comprising: performing a first step of scan-driving the stage so that a maximum acceleration becomes a first acceleration; and performing a second step of scan-driving the stage while exposing the substrate so that the maximum acceleration becomes a second acceleration after the performing the first step, wherein the first acceleration is lower than the second acceleration.