Sinusoidal Stage Motion for Lithography Exposure Efficiency
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Solution Overview
Problem
Conventional step-and-scan lithography machines have inefficient scanning and exposing processes, with only 20% of the total time being effective for exposure, leading to low production efficiency and increased disturbance due to rapid acceleration and deceleration stages.
Innovation Solution
The scanning and exposing method employs sinusoidal speed curves for both the wafer and reticle stages, allowing exposure to start from zero speed and continue until speeds decrease to zero, increasing effective exposure time and reducing waste, while also minimizing disturbance through gentle acceleration and deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional step-and-scan lithography uses rapid acceleration and deceleration stages, then the scanning and exposing process can complete faster, but the effective exposure time is reduced to only 20% of total time and production efficiency decreases
Solution Approach 1:
The patent applies continuous scanning exposure without traditional acceleration and deceleration stages. The wafer stage and reticle stage move continuously through the exposure field, eliminating the need to stop and restart at each exposure shot, thereby maintaining continuous useful action and maximizing effective exposure time throughout the entire scanning process.
Solution Approach 2:
The patent implements periodic exposure shots during continuous scanning. Multiple exposure shots are performed at regular intervals along the scanning path, converting the continuous scanning motion into periodic exposure events. This allows the system to maintain high speed continuous motion while still achieving effective exposure at multiple points, thereby increasing overall productivity without sacrificing effective exposure time.
2Speed
If conventional lithography uses rapid acceleration and deceleration, then the scanning process can be completed quickly, but machine disturbance increases
Solution Approach 1:
By performing exposure shots at periodic intervals during continuous scanning rather than requiring acceleration and deceleration at each shot, the system maintains constant velocity motion. This periodic exposure approach eliminates the harmful acceleration and deceleration forces that cause machine disturbance, while still achieving multiple exposures through the periodic nature of the scanning process.
3Manufacturing precision
If conventional lithography requires stabilization time at uniform speed, then exposure precision can be maintained, but the total time for scanning and exposing increases
Solution Approach 1:
The patent eliminates the need for separate stabilization periods by maintaining continuous uniform motion throughout the entire scanning process. The wafer stage and reticle stage move continuously at constant velocity through the exposure field without stopping or stabilizing at intermediate points, thereby maintaining exposure precision through continuous motion control while eliminating the time loss associated with repeated acceleration, stabilization, and deceleration cycles.
Solution Approach 2:
By implementing periodic exposure shots during continuous scanning, the system achieves multiple exposures without requiring stabilization time between shots. The periodic nature of the exposure events occurs naturally during the continuous uniform motion, eliminating the need for additional stabilization periods while maintaining the precision required for each exposure shot.
Data Source
AI summary
The present disclosure provides a lithography machine and a scanning and exposing method thereof. According to the scanning and exposing method, the scanning and exposing process for a whole wafer includes two alternately circulated motions: a scanning and exposing motion and a stepping motion; and the scanning and exposing motion is a sinusoidal motion rather than a rapid-acceleration uniform-speed rapid-deceleration scanning and exposing motion in the conventional techniques. During the scanning of a single exposure shot, it may begin to scan the exposure shot once a wafer stage and a reticle stage begin to accelerate from zero speed. And the scanning and exposing may not end until the speeds of the wafer stage and the reticle decrease to zero. Therefore, the effective time of the scanning and exposing in the scanning and exposing motion is greatly increased and the production efficiency of the wafer is improved.