Active Mount Interconnection Member Cut for Crosstalk Reduction
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Solution Overview
Problem
Conventional active mounts in lithographic apparatuses face challenges in effectively reducing vibrations and disturbances affecting the projection system, leading to residual crosstalk between piezoelectric elements that impact the accuracy and stability of pattern transfer.
Innovation Solution
Incorporating a cut in the interconnection member between the first and second piezoelectric elements to reduce crosstalk, allowing for precise tuning of the active mount by measuring and adjusting the remaining crosstalk until it reaches a predetermined level, thereby maintaining high stiffness in the force direction while minimizing deformation and compensating positive and negative deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a first piezo element is provided to exert a force on the projection system and a second piezo element to measure the force, then the effect of vibrations on the projection system may be reduced, but crosstalk between the piezoelectric elements remains which impacts accuracy and stability
Solution Approach 1:
The interconnection member is divided into multiple segments by introducing cuts, which isolates the first and second piezoelectric elements from each other. This segmentation prevents mechanical coupling and crosstalk between the actuator and sensor, allowing the sensor to accurately measure only the force exerted by its own piezo element without interference from the other element.
Solution Approach 2:
The harmful mechanical coupling path between the first and second piezoelectric elements is extracted and removed by introducing cuts in the interconnection member. This eliminates the crosstalk pathway while preserving the necessary structural connection for force transmission to the projection system.
2Force
If the interconnection member is made rigid to maintain high stiffness in the force direction, then force transmission efficiency is improved, but deformation occurs which causes crosstalk between piezoelectric elements
Solution Approach 1:
The interconnection member is segmented into multiple parts through cuts, creating isolated sections that prevent the transmission of deformations between piezoelectric elements. Each segment maintains sufficient stiffness for its local function while the overall structure eliminates crosstalk by breaking the continuous deformation path.
Solution Approach 2:
Different regions of the interconnection member are given different properties: the segments connected to each piezoelectric element maintain high local stiffness for efficient force transmission, while the cuts create discontinuities that prevent the propagation of deformations that would cause crosstalk. This local differentiation allows simultaneous achievement of force efficiency and crosstalk reduction.
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 significantly reduces crosstalk between the piezoelectric elements, enhancing the frequency response and stability of the active mount, leading to improved vibration damping and pattern transfer accuracy in lithographic apparatuses.
Implementation Method 1
a first piezoelectric element to exert a force on the projection system
Implementation Method 2
a second piezo element to measure the force
Data Source
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AI summary
A lithographic apparatus includes an illumination system configured to condition a radiation beam, a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam, a substrate table constructed to hold a substrate, and a projection system configured to project the patterned radiation beam onto a target portion of the substrate. The projection system is mounted on a reference structure of the lithographic apparatus by a mount of the lithographic apparatus. The mount includes a first piezoelectric element to exert a force on the projection system, a second piezoelectric element to measure the force, and an interconnection member interposed between the first and second piezoelectric elements, the interconnection member comprising a cut.