Substrate Alignment Device with Constrained Z-Motion
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Solution Overview
Problem
Current substrate alignment systems face challenges in achieving high precision and efficiency, particularly in vacuum environments, due to long travel paths and difficulties with air bearings, leading to imprecise positioning and increased complexity.
Innovation Solution
A device and method utilizing a single sample holder with three degrees of freedom and a second holder with a single but highly precise degree of freedom, along with detection units limited to the Z-direction, to minimize travel paths and enhance precision, while optics are positioned outside the alignment chamber to avoid optical errors and simplify vacuum operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If air bearings are used for friction-free movement, then ease of operation is improved, but reliability deteriorates in vacuum environments
Solution Approach 1:
The patent replaces air bearings with a mechanical degree of freedom constraint system. Instead of using air lubrication for friction-free movement, the invention constrains the lower sample holder to move only in the Z-direction through mechanical design, eliminating the need for air bearings and making the system compatible with vacuum environments.
2Ease of operation
If long travel paths are used for sample holders, then ease of operation is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent inverts the conventional approach by giving the upper sample holder full mobility (three degrees of freedom) and constraining the lower sample holder to a single degree of freedom. This allows precise positioning through the upper holder's movement while the lower holder provides stable, constrained support, achieving high precision without requiring long travel paths for both holders.
Solution Approach 2:
The patent segments the degrees of freedom between two sample holders. The upper holder handles X-Y positioning and Z-movement (three degrees of freedom), while the lower holder is constrained to Z-movement only (one degree of freedom). This segmentation allows each holder to perform its specific function optimally, improving overall positioning accuracy.
3Ease of operation
If multiple motors and bearings are used, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates unnecessary motors and bearings by constraining the lower sample holder to a single degree of freedom. This removes the need for complex multi-axis motor systems and multiple bearing types, simplifying the overall device while maintaining operational capability through the upper sample holder's full mobility.
4Ease of operation
If air bearings are used for vacuum operation, then ease of operation is improved, but manufacturing precision deteriorates due to positioning errors
Solution Approach 1:
The patent replaces the air bearing mechanical system with a constrained mechanical degree of freedom system. By limiting the lower sample holder to Z-direction movement only, the invention achieves precise positioning without relying on air bearings, thereby maintaining both ease of operation and manufacturing precision in vacuum environments.
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 2d~2f
AI summary
The invention relates to a method for aligning and bringing a first substrate (14) in contact with a second substrate (14') as well as to a corresponding device comprising at least four detection units (3, 3', 3", 3"') of which: a) at least two first detection units (3, 3") can be moved at least in the X direction and the Y direction; and b) at least two second detection units (3', 3"') can be moved exclusively in the Z direction.