Chuck Segments for Nanometric Substrate Positioning
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Solution Overview
Problem
The existing methods for positioning an image sensor relative to a substrate during manufacturing or inspection processes face accuracy and force challenges due to substrate elevation, which results in navigation errors and vibrations, especially when high precision within nanometric scales is required.
Innovation Solution
A support module with independently movable chuck segments and piezoelectric motors that perform nanometric scale elevation and lowering movements, along with additional piezoelectric motors to counter movements and compensate for tilt errors, is used to accurately position the substrate with reduced force and increased precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire substrate is elevated or lowered to position the image sensor, then the image sensor can be positioned at the required distance from the substrate, but the positioning accuracy deteriorates and navigation errors increase
Solution Approach 1:
The chuck is divided into multiple independently controllable segments. Instead of elevating or lowering the entire substrate, only specific chuck segments are moved vertically to adjust the position of local substrate areas. This segmentation allows precise local positioning without affecting the global substrate orientation, thereby eliminating navigation errors while achieving the required positioning accuracy.
Solution Approach 2:
Different regions of the substrate are treated differently through independent chuck segment control. Each chuck segment can be positioned with nanometric precision to accommodate local requirements of the image sensor positioning, while other regions remain undisturbed. This local quality approach ensures high positioning accuracy without introducing global navigation errors.
2Speed
If the entire substrate is elevated or lowered during positioning, then the image sensor distance can be adjusted, but the positioning duration increases and substantial forces are required
Solution Approach 1:
By segmenting the chuck into independently controllable parts, only the necessary substrate areas are moved during positioning. This reduces the mass that needs to be accelerated and decelerated, thereby increasing positioning speed and reducing the time required for the positioning operation compared to moving the entire substrate.
Solution Approach 2:
Instead of moving the entire substrate (excessive action), only the specific chuck segments supporting the areas of interest are moved (partial action). This reduces the inertial effects and forces required, enabling faster positioning with shorter duration while achieving the same imaging goal.
3Force
If the entire substrate is elevated or lowered, then the image sensor positioning can be achieved, but substantial forces must be applied to the substrate
Solution Approach 1:
The chuck segments are designed to move independently with small displacements. This segmentation allows the positioning force to be concentrated on local areas rather than distributed across the entire substrate. The forces required to move small chuck segments are substantially lower than those needed to move the complete substrate, reducing mechanical stress and potential damage.
Solution Approach 2:
The system changes the positioning parameter from global substrate displacement to local chuck segment displacement. This parameter change reduces the mass being moved and consequently the forces required, while achieving the same effect of positioning the image sensor at the correct distance from the substrate surface.
4Measurement precision
If the stage has pitch or tilt errors, then the interferometer measurement may be affected, but X and Y navigation errors result that amplify with lever arm length
Solution Approach 1:
By using independently controllable chuck segments, the system can locally compensate for pitch and tilt errors without moving the entire substrate. Each segment can be adjusted to maintain the correct local orientation, preventing the amplification of angular errors over the lever arm length while preserving interferometer measurement accuracy.
Solution Approach 2:
Instead of trying to maintain perfect global stage alignment and compensate for errors, the system inverts the approach by allowing local orientation adjustments at the chuck segment level. This local compensation eliminates the need for perfect global alignment, reducing navigation errors while maintaining measurement precision.
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 solution enhances the accuracy and speed of substrate positioning, reduces the required forces, and minimizes navigation errors, enabling precise image acquisition by moving only selected areas of the substrate, thus improving the overall positioning process.
Implementation Method 1
The vertical stage may include multiple piezoelectric motors. Each piezoelectric motor may be configured to perform nanometric scale elevation and lowering movements.
Implementation Method 2
The support module may include a controller for controlling the multiple piezoelectric motors thereby compensating for a tilt error of an area of the substrate.
Data Source
AI summary
According to an embodiment, a support module is provided for supporting a substrate. The support module may include a chuck and a vertical stage. The chuck may include multiple chuck segments that are independently movable. When the substrate is positioned on the chuck, different chuck segments are positioned under different areas of the substrate. The vertical stage may include multiple piezoelectric motors. Each piezoelectric motor may be configured to perform nanometric scale elevation and lowering movements. The multiple piezoelectric motors may be configured to independently move the multiple chuck segments.