公开(公告)号：US06925478B2

公开(公告)日：2005-08-02

申请号：US09739331

申请日：2000-12-19

申请人： Alireza Jabbari ,  David P Stumbo ,  Michael Sogard

发明人： Alireza Jabbari ,  David P Stumbo ,  Michael Sogard

IPC分类号： G01D3/028 ,  H03H17/02 ,  H03H17/06 ,  G06F17/10

CPC分类号： H03H17/0294

摘要： A system and methods for generating a variable rate filtered output using synchronous filters having the same filter sampling time, that avoids complexities of asynchronous filters. A system employs multiple filters that are staggered in time and set so that the output of one of the multiple filters is available whenever a secondary process requires state information. In another embodiment, the synchronous filters are programmable so as to change the filter sampling time. This configuration is possible when it is known that the prescribed time interval of the secondary process is longer than the filter sampling time and the prescribed time interval is an integer multiple of the filter sampling time. By using programmable filters, the number of filters required to accommodate a certain prescribed time interval can be minimized. Whether a system employs multiple non-programmable filters staggered in time or programmable filters, the invention achieves producing a variable rate filtered output while using synchronous filters. Thus, computationally intensive and complicated variable rate filters can be avoided while minimizing processor requirements. In another aspect of the invention, the inventive method of generating a variable rate filtered output is employed in a lithography system to control the movements of various components therein. In one embodiment, the filtered outputs are used to estimate the relative positions of the reticle and the wafer. With the variable rate feature, the lithography system can dynamically accommodate for the noise arising from component movements and other sources in the wafer exposure process.

摘要翻译： 使用具有相同滤波器采样时间的同步滤波器来生成可变速率滤波输出的系统和方法，避免异步滤波器的复杂性。 系统采用多个过滤器，这些过滤器在时间上交错设置，使得当辅助过程需要状态信息时，多个过滤器之一的输出可用。 在另一个实施例中，同步滤波器是可编程的，以便改变滤波器采样时间。 当已知二次处理的规定时间间隔长于滤波器采样时间并且规定的时间间隔是滤波器采样时间的整数倍时，这种配置是可能的。 通过使用可编程滤波器，可以最小化容纳特定规定时间间隔所需的滤波器数量。 无论系统采用多个在时间上交错的非可编程滤波器或可编程滤波器，本发明实现了在使用同步滤波器时产生可变速率滤波输出。 因此，可以避免计算密集型和复杂的可变速率滤波器，同时最小化处理器要求。 在本发明的另一方面，在光刻系统中采用产生可变速率滤波输出的本发明方法来控制其中各种部件的移动。 在一个实施例中，滤波的输出用于估计标线片和晶片的相对位置。 利用可变速率特征，光刻系统可以动态地适应晶片曝光过程中由元件移动引起的噪声和其他来源。