Bent End Effector Arm for Straight-Line Substrate Transport
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Solution Overview
Problem
Existing substrate transport systems in clean or vacuum environments, such as those used in semiconductor manufacturing, face challenges in minimizing footprint and cycle time while maintaining efficient substrate handling, particularly due to the need for precise and linear movement of arms with unequal link lengths to optimize space utilization and transport efficiency.
Innovation Solution
A transport apparatus with a drive system and an arm comprising links of different effective lengths, where the end effector's movement is constrained to follow a substantially straight radial path through the use of non-circular pulleys and bands, allowing for efficient substrate transport without additional rotational axes, thereby minimizing space requirements and cycle time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If arms with unequal link lengths are used for substrate transport, then space utilization and footprint are improved, but achieving precise linear movement becomes more difficult
Solution Approach 1:
The patent applies asymmetry by using arms with unequal link lengths (first link length different from second link length) to optimize space utilization and minimize footprint. This asymmetric configuration allows the transport system to operate efficiently within a smaller area while maintaining precise substrate handling capabilities through the specific geometric relationships between the links.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the geometric parameters of the arm mechanism. Specifically, the relationship between link lengths (L1 and L2) and the rotation angles (θ1 and θ2) is optimized to achieve linear end effector movement. By adjusting these parameters and maintaining specific mathematical relationships, the system compensates for the unequal link lengths and ensures precise linear transport motion.
2Manufacturing precision
If additional rotational axes are added to control end effector orientation, then movement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the orientation control function from a separate rotational axis and integrates it into the arm's kinematic structure itself. By carefully designing the relationship between the two rotational joints and the unequal link lengths, the system achieves both linear translation and proper end effector orientation without requiring an additional dedicated rotational axis, thereby reducing overall system complexity.
Solution Approach 2:
The arm mechanism serves multiple functions simultaneously: it provides both the linear transport motion and the end effector orientation control through its two rotational joints and unequal link lengths. This multi-functionality eliminates the need for separate dedicated components for each function, reducing device complexity while maintaining precise movement control.
3Manufacturing precision
If equal link lengths are used in the arm, then achieving linear end effector movement is easier, but space utilization and footprint are worsened
Solution Approach 1:
The patent deliberately uses asymmetric link lengths (L1 ≠ L2) to minimize the footprint and optimize space utilization. By carefully selecting the specific ratio and values of these unequal link lengths and coordinating them with appropriate rotation angles, the system achieves both compact dimensions and the required linear movement precision, overcoming the traditional assumption that equal link lengths are necessary for linear motion.
Solution Approach 2:
The patent optimizes the geometric parameters of the arm mechanism by adjusting the link lengths (L1 and L2) and rotation angles (θ1 and θ2) to achieve linear end effector movement. Through careful parameter selection and mathematical relationships between these variables, the system maintains movement precision while enabling a more compact, space-efficient configuration with smaller footprint.
Data Source
AI summary
A transport apparatus including a drive with a drive axis and a first arm connected to the drive. The first arm includes a first link, a second link and an end effector connected in series with the drive. The end effector includes a substrate support section and a leg connecting the substrate support section to a wrist joint of the end effector with the second link. The leg has a first section connected to the wrist joint, a second section connected to the substrate support section, and a bend portion between the first and second sections such that the first and second sections are angled or offset relative to each other. Connection of the leg to the second link at the wrist joint is offset relative to a centerline of the substrate support section and offset relative to the drive axis.