Multi-axis positioning device with piezoelectric motors and pneumatic bearings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current multi-axis positioning devices face challenges such as complexity, particulate contamination risk, difficulty in maintaining focal point co-location during tip and tilt adjustments, mechanical bulkiness, and the need for stability, rigidity, low mass, and high throughput in semiconductor wafer positioning.
Innovation Solution
A multi-axis positioning system comprising an x-y stage assembly with linear actuators, a bottom plate assembly with piezoelectric motors and resilient suspension members, and a top plate assembly connected via a thin slotted flexure assembly, along with precision bearings and position sensors, to provide precise translational and rotational movements while minimizing complexity and mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanically driven systems are used for multi-axis positioning, then positioning capability is achieved, but the system becomes bulky and complex
Solution Approach 1:
The patent replaces traditional mechanical drive systems with piezoelectric motors that utilize piezoelectric effect to generate motion through electrical fields. This substitution eliminates complex mechanical transmission components while achieving precise multi-axis positioning control, directly resolving the contradiction between positioning capability and system complexity
2Ease of operation
If traditional multi-axis positioning device designs are used, then positioning function is provided, but the risk of particulate contamination increases
Solution Approach 1:
The patent employs a pneumatic bearing system where pressurized gas is introduced between the top plate and bottom plate to create a non-contact air bearing. This eliminates mechanical contact and friction, preventing particulate generation from traditional mechanical components while maintaining precise positioning function, thus resolving the contamination issue
3Speed
If stiff positioning devices are used to provide high bandwidth positioning, then positioning performance is improved, but the mass increases
Solution Approach 1:
The patent utilizes thin flexure elements with slotted geometry that provide the necessary structural flexibility and compliance while maintaining low mass. These flexures work in conjunction with the pneumatic bearing system to achieve high-bandwidth positioning without requiring heavy stiffening components, resolving the mass-speed contradiction
4Measurement precision
If multi-axis positioning devices are configured for dynamic compensation, then positioning accuracy is improved, but the device becomes too complicated
Solution Approach 1:
The patent designs the top plate and bottom plate assemblies to serve multiple functions simultaneously: they provide mechanical support, accommodate piezoelectric motors for drive functions, house pneumatic bearings for non-contact support, and integrate flexure elements for compliance. This multi-functionality reduces the need for separate dedicated components, achieving high positioning accuracy while minimizing overall device complexity
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 system achieves stable, accurate, and high-bandwidth positioning with reduced complexity and mass, minimizing contamination risks and maintaining precise control over Z-axis, theta, tip, and tilt movements, enhancing throughput and positioning accuracy for semiconductor wafers.
Implementation Method 1
at least one piezoelectric motor which is secured to the bottom plate body and including a piezoelectric motor mount surface whereby the piezoelectric motor is configured to rotate the mount surface relative to the bottom plate body
Implementation Method 2
each include a pressurized gas port
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A multi-axis positioning system that may be used in conjunction with an inspection system includes multiple position sensors corresponding to multiple axes in conjunction with multiple motors also corresponding to multiple axes to provide high accuracy, high load and extended travel for controllable movement of an object in up to 6 degrees of freedom. Some embodiments of the multi-axis positioning system may include and x-y stage assembly, a bottom plate assembly coupled to the x-y stage assembly, a top plate assembly coupled to the bottom plate assembly, and a chuck secured to the top plate assembly with multiple position sensors configured to measure displacement between the x-y stage assembly and top plate assembly.