Alignment Mark Count Acquisition for Photolithography Buffer Time
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Solution Overview
Problem
In photolithography exposure processes, the inefficiency in semiconductor manufacturing arises from the long waiting times due to mismatched alignment and exposure times of wafers, which is influenced by the alignment mark count, necessitating a method to determine optimal alignment mark counts to reduce buffer times and enhance exposure efficiency.
Innovation Solution
An alignment mark count acquiring method that calculates the buffer time between exposure and alignment times and determines the target alignment mark count based on a corresponding relationship between exposure parameters and alignment mark counts to ensure the buffer time is within a preset value, thereby optimizing the exposure process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the alignment mark count is increased to improve alignment precision, then the alignment time increases, but the exposure efficiency decreases due to longer buffer times
Solution Approach 1:
The patent dynamically adjusts the alignment mark count as a variable parameter based on the buffer time between exposure and alignment operations. By changing this parameter adaptively rather than using a fixed value, the system optimizes the balance between alignment precision and exposure efficiency, reducing waiting times while maintaining sufficient alignment accuracy.
Solution Approach 2:
The system transitions from a static alignment mark count to a dynamic adjustment mechanism where the alignment mark count changes based on real-time buffer time measurements. This dynamic approach allows the system to adapt to varying operational conditions, optimizing both alignment precision and exposure efficiency continuously.
2Productivity
If the buffer time between exposure and alignment is reduced to improve exposure efficiency, then the alignment precision may be compromised, but increasing alignment mark count increases waiting time
Solution Approach 1:
The patent implements a feedback mechanism where the actual buffer time between exposure and alignment operations is measured and used to adjust the alignment mark count. This closed-loop control ensures that the system continuously optimizes the balance between exposure efficiency and alignment precision, preventing both excessive waiting times and insufficient alignment accuracy.
Solution Approach 2:
The system automatically adjusts the alignment mark count based on measured buffer times without requiring external intervention. The exposure machine self-regulates the alignment parameters to optimize its own operational efficiency, reducing manual configuration and improving real-time adaptability.
3Device complexity
If a fixed alignment mark count is used to simplify the process, then the device complexity is reduced, but the adaptability to different exposure parameters decreases
Solution Approach 1:
The patent pre-establishes a correspondence relationship between exposure parameters and optimal alignment mark counts. This preliminary preparation allows the system to quickly adapt to different exposure conditions by selecting from pre-analyzed parameter combinations, reducing real-time computational complexity while maintaining high adaptability.
Data Source
AI summary
An alignment mark count acquiring method includes: acquiring a first time at which an exposure machine performs exposure of a first wafer, and acquiring a second time at which the exposure machine performs alignment of a second wafer; acquiring a first buffer time between the second time and the first time when the first time is less than the second time; determining a target alignment mark count of the second wafer according to the exposure parameters of the first wafer and the corresponding relationship when the first buffer time is greater than a preset value, wherein the corresponding relationship is the relationship between the exposure parameters and the alignment mark counts, and the corresponding relationship is used to make the first buffer time to be less than or equal to the preset value; and outputting the target alignment mark count.