Exposure Apparatus Substrate Alignment Measurement Segmentation
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Solution Overview
Problem
Existing lithographic apparatuses face a trade-off between overall productivity and imaging quality, with longer measurement times for accurate substrate alignment deteriorating throughput performance.
Innovation Solution
The exposure apparatus incorporates a substrate holder, a sensor holder, and a mover that couples and decouples to efficiently move the substrate and sensor, allowing for simultaneous measurement and exposure processes without interfering with each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a longer measurement time is used for accurate substrate alignment, then imaging quality is improved, but productivity deteriorates
Solution Approach 1:
The substrate alignment measurement is divided into multiple measurement regions that can be measured sequentially. The measurement device measures different regions at different times, allowing the substrate to be repositioned between measurements. This segmentation enables comprehensive measurement of the entire substrate without requiring the substrate to remain stationary for extended periods, thus maintaining productivity while improving measurement precision.
Solution Approach 2:
The substrate is pre-positioned on the substrate stage before measurement begins. The measurement device then moves to different measurement regions while the substrate remains in place. This preliminary positioning eliminates the need for repeated substrate repositioning and measurement setup, reducing total measurement time and improving productivity while maintaining measurement accuracy.
2Productivity
If multiple substrates are processed simultaneously to improve productivity, then throughput increases, but measurement accuracy deteriorates
Solution Approach 1:
The system divides measurement tasks into segments that can be performed on different substrates at different times. While one substrate is being measured with high precision, other substrates can be prepared or processed. This temporal segmentation allows multiple substrates to be handled without compromising the measurement accuracy of any single substrate.
Solution Approach 2:
A control device coordinates the measurement and processing of multiple substrates. It manages the timing and sequencing of measurements across different substrates, ensuring that high-precision measurements are performed when necessary while maintaining overall productivity through efficient resource allocation and coordination.
Data Source
AI summary
An exposure apparatus arranged to project a radiation beam onto a target portion of a substrate, the exposure apparatus having: a first substrate holder configured to hold the substrate; a second substrate holder configured to hold the substrate; a sensor holder configured to hold a sensor and/or detector; a first measurement device having a first alignment system having an alignment sensor configured to measure positions of a substrate alignment mark on the substrate; a second measurement device having a second alignment system having a further alignment sensor configured to measure positions of the substrate alignment mark on the substrate; a first scale arranged on a lower surface of the first substrate holder; and a first encoder head arranged to cooperate with the first scale, the first encoder head located beneath the first alignment system and held by a stationary support.