Three-Surface Module Stacking for Thermally Stable Alignment
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Solution Overview
Problem
In lithography and microscopy systems, accurately aligning functional elements across multiple modules is challenging, especially when considering thermal expansion or contraction, which can disrupt the alignment of these elements.
Innovation Solution
An assembly with a frame featuring three planar alignment surfaces offset from each other, where each module is supported by three members that abut these surfaces, allowing for precise orientation and positioning. This setup includes an opening for module insertion and removal, with alignment surfaces arranged to maintain alignment independence from temperature variations by defining a thermal centerline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If functional elements are mounted in a frame and aligned with respect to each other, then alignment accuracy is improved, but the alignment becomes sensitive to thermal expansion or contraction
Solution Approach 1:
The patent changes the physical parameters of the alignment system by using three planar alignment surfaces with specific angular offsets instead of conventional parallel surfaces. This geometric parameter change creates a thermal centerline that remains stable during thermal expansion, as the expansion occurs uniformly along all three surfaces rather than causing misalignment between parallel surfaces.
Solution Approach 2:
The patent employs asymmetric alignment surfaces that are angularly offset from each other rather than using symmetric parallel surfaces. This asymmetric configuration with three planes intersecting at specific angles creates a unique thermal centerline that is inherently stable against thermal expansion, resolving the contradiction between alignment precision and thermal sensitivity.
2Manufacturing precision
If modules are arranged in a stack with high accuracy, then alignment precision is improved, but the complexity of the assembly increases
Solution Approach 1:
The three planar alignment surfaces serve multiple functions simultaneously: they provide mechanical support for the modules, establish precise angular relationships between modules, define the thermal centerline for thermal stability, and guide the stacking process. This multi-functionality reduces assembly complexity while maintaining high alignment precision.
Solution Approach 2:
The alignment surfaces are designed to create an equipotential alignment system where all three surfaces intersect at a common thermal centerline. This equipotential configuration ensures that modules stacked against these surfaces automatically achieve high precision alignment without requiring complex adjustment mechanisms, as the geometry itself enforces the alignment.
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 solution enables high-accuracy and reproducible alignment of modules, ensuring that the functional elements remain substantially independent from temperature variations, thereby maintaining the precision of the lithography or microscopy system's performance.
Implementation Method 1
this alignment should in addition at least substantially be impervious to thermal expansion or contraction of the functional elements and/or the frame
Data Source
AI summary
The invention relates to an assembly, preferably for use in a lithography system or a microscopy system, for providing an accurately aligned stack of two or more modules in a stacking direction. Each of the two or more modules comprises three support members. The assembly comprises a frame comprising three planar alignment surfaces which extend in the stacking direction and which are angularly off-set with respect to each other. In addition each of the three support members of each one of the two or more modules, when arranged in said frame, abuts against a corresponding one of the three alignment surfaces. The frame is provided with an opening between two of the three planar alignment surfaces for inserting a module in the assembly, said two planar alignment surfaces on either side of the opening are arranged at least partially facing said opening.