Projection Optical System Thermal Control for Semiconductor Exposure
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Solution Overview
Problem
The existing method for semiconductor device manufacturing using a projection optical system experiences significant aberration changes during the transition from one exposure job to another, leading to reduced throughput and increased difficulty in correcting astigmatism, especially when the time gap between exposure jobs is long.
Innovation Solution
A method that involves controlling the temperature distribution of optical elements in the projection optical system during the transition period between exposure jobs using a reticle stage and projection optical system, where the first reticle is exchanged with the second reticle, and adjusting the temperature to minimize aberration changes by applying thermal energy to reduce astigmatism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If enough time is elapsed between the first exposure job and the second exposure job, then the aberration generated in the projection optical system by the first exposure job is reduced, but the change of the aberration immediately after the second exposure job starts becomes large
Solution Approach 1:
The patent applies temperature control to change the thermal state of the projection optical system. By adjusting the temperature distribution of optical elements during the transition period between exposure jobs, the system compensates for aberration changes and maintains optical performance without requiring long idle times, thus resolving the contradiction between precision and productivity
Solution Approach 2:
The patent performs preliminary temperature adjustment during the transition period (third period) between exposure jobs. By controlling the temperature distribution in advance before the second exposure job starts, the system prepares the optical elements to minimize aberration changes when exposure resumes, allowing short transition times while maintaining precision
2Productivity
If the transition period between exposure jobs is shortened to improve throughput, then productivity increases, but the control of astigmatism becomes more difficult
Solution Approach 1:
The patent actively changes the temperature parameter of optical elements during the shortened transition period. By applying thermal energy control to adjust the temperature distribution, the system compensates for astigmatism that would otherwise be difficult to control with short transition times, enabling both high throughput and precise astigmatism control
Solution Approach 2:
The patent implements temperature control based on detected aberration states. The system monitors the optical system state and adjusts temperature distribution accordingly during the transition period, creating a feedback mechanism that maintains astigmatism control even when transition periods are shortened for improved throughput
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 suppresses aberration changes in the projection optical system, improving throughput by shortening the transition period and facilitating more precise control over astigmatism, thereby enhancing the quality and yield of semiconductor devices.
Implementation Method 1
an exposure apparatus that includes a reticle stage and a projection optical system
Implementation Method 2
performing control, in the first period and the second period, to adjust a temperature distribution of an optical element included in the projection optical system so as to reduce a change in an aberration of the projection optical system
Data Source
AI summary
A method of manufacturing a semiconductor device by using an exposure apparatus having a reticle stage and a projection optical system includes a first period in which substrates are exposed by using a first reticle arranged on the reticle stage, a second period in which substrates are exposed by using a second reticle arranged on the reticle stage, and a third period which is between the first and second periods. The method includes changing, in at least part of the third period, the first reticle arranged on the reticle stage to the second reticle, and performing control, in the first and second periods, to adjust temperature distribution of an optical element of the projection optical system so as to reduce change in aberration of the projection optical system. The third period is shorter than the first period.