Polishing Apparatus Inclination Correction via Self-Aligning Bearing
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Solution Overview
Problem
In chemical mechanical polishing (CMP) processes, uneven pressure distribution of the slurry on the wafer surface occurs due to tilting of the polishing head, leading to inconsistent polishing rates.
Innovation Solution
A polishing apparatus with a self-aligning rolling bearing and an inclination adjusting device that automatically adjusts the rotational shaft to maintain the polishing head perpendicular to the polishing table, ensuring concentric pressure distribution of the slurry on the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the polishing head tilts, then the structure allows simple operation, but the pressure distribution of slurry becomes uneven causing inconsistent polishing rates
Solution Approach 1:
The polishing apparatus employs a feedback mechanism where a sensor detects the inclination angle of the polishing head and sends signals to a control system. The control system then actuates an inclination adjusting device (such as a motor or actuator) to correct the polishing head's angle, ensuring it remains perpendicular to the polishing table. This closed-loop feedback system automatically maintains proper alignment without requiring manual intervention, thus preserving operational simplicity while ensuring consistent polishing rates through accurate pressure distribution.
Solution Approach 2:
The polishing head incorporates a self-aligning bearing that automatically compensates for inclination deviations. The bearing's design allows it to self-correct minor misalignments through its structural characteristics, maintaining the polishing head's perpendicular orientation without requiring external adjustment mechanisms. This self-service approach keeps the system simple to operate while ensuring consistent polishing performance.
2Device complexity
If the polishing head tilts, then the device structure remains simple, but the pressure distribution center deviates from wafer center causing uneven polishing
Solution Approach 1:
The system uses inclination sensors to continuously monitor the polishing head's angular position and provides feedback to a control system. When deviation from the perpendicular position is detected, the control system activates an inclination adjusting device to correct the angle. This feedback mechanism maintains pressure distribution concentricity with the wafer center while avoiding complex manual adjustment structures.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with an automated inclination adjusting device driven by motors or actuators controlled by electronic systems. This substitution reduces the need for complex mechanical linkages and manual adjustment components, keeping the overall device structure relatively simple while achieving precise control over pressure distribution concentricity.
3Device complexity
If manual adjustment of polishing head inclination is used, then the device structure is simple, but the adjustment precision and consistency are insufficient
Solution Approach 1:
The polishing apparatus incorporates inclination sensors that precisely detect the angular position of the polishing head and provide real-time feedback to a control system. This feedback enables accurate measurement of inclination angles and allows for precise automated adjustment, replacing imprecise manual adjustment methods while maintaining relatively simple device structure through the use of standard sensor and actuator components.
Solution Approach 2:
Manual inclination adjustment is replaced with an automated system using inclination sensors and motor-driven adjusting devices. This substitution eliminates the limitations of manual adjustment precision while avoiding the need for complex mechanical adjustment mechanisms, achieving high measurement precision through electronic sensing and control.
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 maintains consistent polishing rates by ensuring the pressure distribution of the slurry remains concentric with the wafer center, reducing variations in polishing outcomes.
Implementation Method 1
a self-aligning rolling bearing that tiltably supports the rotational shaft
Implementation Method 2
a detector configured to detect an inclination of the rotational shaft
Implementation Method 3
an inclination adjusting device configured to adjust the inclination of the rotational shaft
Implementation Method 4
a radial rolling bearing that receives a radial load of the rotational shaft
Data Source
AI summary
A polishing apparatus capable of correcting an inclination of a polishing head is disclosed. The polishing apparatus includes: a polishing table configured to support a polishing pad thereon; a polishing head configured to press a substrate against the polishing pad; a rotational shaft coupled to the polishing head; a self-aligning rolling bearing that tiltably supports the rotational shaft; a radial rolling bearing that receives a radial load of the rotational shaft; a detector configured to detect an inclination of the rotational shaft; and an inclination adjusting device configured to adjust the inclination of the rotational shaft.