Polishing Apparatus Swing Arm Torque Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing polishing apparatuses face challenges in accurately detecting the polishing end point due to small changes in torque current, which can lead to excessive polishing or incomplete polishing, especially when noise influences the torque current waveform.
Innovation Solution
A polishing apparatus configuration that includes a swing arm holding the top ring, an arm drive section, and an arm torque detection section to directly or indirectly detect arm torque, allowing for precise detection of the polishing end point by measuring the arm torque, reducing noise associated with table rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque current is used to detect polishing end point, then polishing end point detection is enabled, but detection accuracy deteriorates due to small changes and noise influence
Solution Approach 1:
The patent extracts the torque measurement from the rotating polishing table system to a separate swing arm system. The swing arm is driven by a motor separate from the table rotation motor, allowing torque measurement independent of table rotation noise. This separation removes the harmful factor of rotation-induced noise while preserving the useful function of torque-based end point detection.
Solution Approach 2:
The swing arm acts as an intermediary mechanism between the polishing contact and the torque measurement system. Instead of measuring torque directly at the rotating table, the swing arm transmits the polishing load to a separate drive motor, mediating the measurement process and isolating it from rotation-related noise and interference.
2Ease of operation
If table rotation is used for polishing, then polishing function is achieved, but noise is generated that interferes with torque current measurement
Solution Approach 1:
The patent segments the polishing system into two independent parts: the table rotation mechanism for polishing and the swing arm drive mechanism for torque measurement. This segmentation separates the useful polishing function from the harmful noise generation, allowing each to operate independently without interfering with the other's measurement or control functions.
Solution Approach 2:
The patent replaces the mechanical torque measurement approach (measuring torque current from the table rotation motor) with an alternative mechanical system (swing arm with separate drive motor). This substitution eliminates the measurement interference caused by table rotation while maintaining the essential torque-based detection capability.
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 configuration improves the accuracy of polishing end point detection by reducing noise and ensuring precise control, thereby preventing excessive polishing and ensuring optimal surface planarization.
Implementation Method 1
an arm torque detection section that directly or indirectly detects arm torque applied to the swing arm
Implementation Method 2
the polishing frictional force generated when the polishing target is polished appears as a drive load of the drive section that drives the polishing table or the top ring to rotate
Data Source
AI summary
In a scheme in which a top ring is held to an end portion of a swing arm, the present invention improves accuracy of polishing end point detection. A polishing apparatus for polishing between a polishing pad 10 and a semiconductor wafer 16 disposed opposed to the polishing pad 10 includes a polishing table 30A for holding the polishing pad 10 and a top ring 31A for holding the semiconductor wafer 16. A swing shaft motor 14 swings a swing arm 110 for holding the top ring 31A. The arm torque detection section 26 detects arm torque applied to the swing arm 110. An end point detection section 28 detects a polishing end point indicating an end of polishing based on the detected arm torque.