Polishing Head and Transfer Station Alignment Using Two-Sensor Calibration
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Solution Overview
Problem
Existing calibration methods for polishing head and transfer station alignment in CMP equipment are complex, inefficient, and require multiple sensors, leading to increased manual calibration difficulty and prolonged alignment times as the number of polishing units increases.
Innovation Solution
A device and method featuring a transfer station that reciprocates along a linear trajectory and a polishing head that rotates circumferentially, with a sensor assembly measuring distances at radial ends to determine the coincidence of central axes, using a determining unit to output minimum distance or difference values for alignment, allowing for efficient and precise calibration with fewer sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If four sensors are used for alignment calibration, then alignment coverage is improved, but device complexity and data processing complexity increase
Solution Approach 1:
The patent extracts the essential alignment information from four sensors to only two sensors. By positioning two sensors at radial ends of the transfer station and using the rotational movement of the polishing head, the system obtains sufficient alignment data with fewer sensors, thereby reducing device complexity while maintaining alignment precision.
Solution Approach 2:
The patent uses the rotational trajectory of the polishing head as a virtual reference to copy the alignment information that would otherwise require multiple physical sensors. The rotational movement allows the same polishing head to be measured at multiple angular positions, effectively creating virtual measurement points without additional hardware.
2Measurement precision
If four sensors and complex calculations are used for alignment, then alignment coverage is improved, but alignment time increases
Solution Approach 1:
The patent extracts only the essential alignment parameters from the sensor measurements, focusing on the minimum distance or difference values between the polishing head outer edge and the sensor at radial ends. This extraction approach reduces calculation complexity and accelerates the alignment process while maintaining precision.
Solution Approach 2:
The patent replaces complex multi-sensor mechanical alignment systems with a simplified system using rotational movement and minimal sensors. The alignment is achieved through the natural rotational trajectory of the polishing head combined with linear reciprocation of the transfer station, eliminating the need for complex calculation systems.
3Measurement precision
If manual calibration is performed for multiple polishing units, then alignment accuracy is maintained, but calibration workload and difficulty increase
Solution Approach 1:
The patent enables the alignment system to self-calibrate by utilizing the inherent rotational and reciprocating movements of the equipment. The system automatically determines alignment status by monitoring distance changes between the polishing head and sensors during normal operational movements, eliminating the need for complex manual calibration procedures.
Solution Approach 2:
The patent creates a universal alignment method that works for multiple polishing units and transfer stations using the same two-sensor configuration. The alignment approach is applicable regardless of the number of polishing units, providing a scalable solution that maintains ease of operation while ensuring alignment accuracy across the entire system.
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 approach significantly enhances calibration efficiency, precision, and user-friendliness by minimizing detection errors and data processing complexity, enabling swift and accurate alignment even in complex scenarios.
Implementation Method 1
a sensor assembly used for monitoring the change of a distance between an outer edge of the polishing head and a sensor
Data Source
AI summary
The invention discloses a device for calibrating working positions of a polishing head and a transfer station, comprising: a transfer station capable of reciprocating along a linear trajectory; a polishing head capable of rotating in a circumferential direction, with a rotational trajectory intersecting with the linear trajectory at least once; a sensor assembly used for monitoring the change of a distance between an outer edge of the polishing head and a sensor, comprising the sensor, and capable of measuring the distance at least at two radial ends of the transfer station; and a determining unit used for outputting a minimum linear distance between the outer edge of the polishing head and the sensor monitored by the sensor assembly to determine whether central axes of the polishing head and the transfer station coincide. The invention also discloses a method for calibrating working positions of a polishing head and a transfer station. The device and method have high calibration efficiency, low requirement for the installation position of the sensor, and minimal detection errors.