SCARA Substrate Transport Pulley Layout for Low-Volume Chambers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current substrate transport robots in semiconductor processing have a high internal chamber volume due to the height of the pulley system, which increases processing time and costs, and face issues with maintaining constant band tension across varying temperatures.
Innovation Solution
A compact substrate transport apparatus with a splitting drive pulley system that shares band interface levels and uses a passive band tensioner to maintain constant tension, reducing the internal chamber height and accommodating thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional stacked pulley arrangement is used, then each forearm can be driven independently, but the height of the pulley system becomes at least four times the height of a single band, increasing the internal chamber volume
Solution Approach 1:
The patent combines the drive mechanisms for multiple forearms into a single shared pulley system. Instead of having separate pulleys for each forearm, a common pulley is used to drive multiple forearms simultaneously through shared transmission loops, reducing the overall height requirement while maintaining independent control capability
Solution Approach 2:
The patent transitions from a vertical stacking arrangement of pulleys (height dimension) to a horizontal/sid-by-side arrangement. By locating pulleys side by side rather than stacked vertically, the system achieves the same functional independence while dramatically reducing the height dimension of the pulley system
2Reliability
If larger pulley system is used to accommodate thermal expansion, then tension can be maintained, but the internal chamber volume increases
Solution Approach 1:
The patent incorporates passive thermal compensation mechanisms that automatically adjust band tension in response to temperature changes. This allows the system to maintain reliable tension consistency without requiring oversized pulleys, as the tension is dynamically adapted to thermal expansion conditions
Solution Approach 2:
The patent explicitly accounts for thermal expansion effects in the pulley and band design. By designing the transmission system to accommodate expected thermal growth, the patent maintains proper tension without requiring excessive clearance or larger components, optimizing the balance between reliability and compactness
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 decreases the internal volume of the transport chamber, enhances processing efficiency, and maintains consistent band tension across temperature variations, thereby improving the throughput and reducing costs.
Implementation Method 1
the difference in the coefficients of thermal expansion between at least the transport robot arm links and the bands 801, 802, 811, 812 induces a difference in the distance between pulleys and the length of the bands 801, 802, 811, 812
Data Source
AI summary
A substrate processing apparatus including a frame, a first SCARA arm having an end effector and being configured to extend and retract along a first axis, a second SCARA arm having an end effector and being configured to extend and retract along a second axis, a drive section including a splitting drive pulley rotatably mounted to rotate at an axis of rotation of the drive section that is shared by the first and second SCARA arms, the splitting drive pulley being coupled to at least two idler pulleys by respective segmented transmission loops of separate band segments so that the splitting drive pulley is a common pulley splitting one degree of freedom of the drive section between the at least two idler pulleys so as to commonly drive the at least two idler pulleys, wherein at least one band of each respective transmission loop share a common band interface level.