Screw Transmission Flange Structure for Reticle Stage Vibration Decoupling
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Solution Overview
Problem
Existing screw transmission drives in reticle stages for semiconductor lithography experience oscillations and vibrations that can cause unintended position changes of the mask, leading to corrupted examination results due to the lack of effective decoupling mechanisms.
Innovation Solution
A spindle flange design with six elastically deformable struts of identical length, arranged in pairs at regular intervals on coaxial linking circles with a radius ratio of 0.5, allows for high axial stiffness while enabling radial displacement and decoupling of vibrations, eliminating the need for additional decoupling elements like flexures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a screw transmission drive is used for the reticle stage, then linear movement of the reticle stage can be achieved, but oscillations and vibrations are transmitted to the reticle stage causing position changes in the nanometers to sub-nanometers range
Solution Approach 1:
The patent introduces a decoupling element positioned between the threaded spindle and the reticle stage. This intermediary component absorbs and isolates oscillations and vibrations generated by the screw transmission drive, preventing them from being transmitted to the reticle stage while still allowing linear movement to be effectively transferred.
Solution Approach 2:
The patent modifies the mechanical parameters of the connection between the threaded spindle and reticle stage by introducing the decoupling element. This changes the stiffness, damping, and natural frequency characteristics of the system, thereby reducing the transmission of harmful vibrations while maintaining the necessary movement capability.
2Object-affected harmful factors
If flexures are provided for decoupling oscillations and vibrations, then some vibration isolation can be achieved, but the complexity of the screw transmission drive increases
Solution Approach 1:
The patent divides the connection system into distinct functional segments: the threaded spindle for generating motion, the decoupling element for vibration isolation, and the reticle stage for holding the mask. This segmentation allows each component to be optimized independently, with the decoupling element specifically designed to address vibrations without complicating the overall drive system.
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
The design significantly reduces the transmission of radial oscillations and vibrations to the reticle stage, minimizing the risk of mask movement in the nanometers or sub-nanometers range, thereby improving measurement accuracy and reducing the risk of incorrect exposures.
Implementation Method 1
six elastically deformable struts of identical length which are fixedly clamped at both ends
Data Source
AI summary
The invention relates to a screw transmission drive, in particular for the reticle stage of a device for lithography applications, comprising a leadscrew, which has a power transmission thread and a leadscrew nut which interacts with the power transmission thread, and a controllable drive for rotating the leadscrew, wherein the leadscrew nut is connected to a leadscrew flange for connection to a component to be moved relative to the drive; the leadscrew flange has two connection elements for connecting, respectively, to the leadscrew nut and to the component to be moved, the connection elements being connected by six elastically deformable struts of identical length which are fixedly clamped at both ends; the clamping points of the struts at the connection elements are distributed, in two parallel connection planes, in pairs at regular intervals over respective connection circles such that each pair of mutually adjacent struts includes an angle; the ratio of the radii of the two connection circles is 0.5, and the connection circles are coaxially located on a common longitudinal axis. The invention also relates to a reticle stage and to a device having a reticle stage, the reticle stage having a screw transmission drive according to the invention.