Web-Based CMP Tensioning via Encoder Wheel Radius Calculation
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Solution Overview
Problem
Conventional methods for determining the radius of a supply roll in web-based CMP systems are unreliable for next-generation polishing articles with textured surfaces, leading to inconsistent or improper tensioning, which can cause the polishing article to break, stretch, or wrinkle, resulting in inconsistent substrate processing and system downtime.
Innovation Solution
The method involves measuring the polishing article advancement length using an encoder wheel and determining the tensioning torque based on the measured length, allowing for consistent tensioning of the polishing article by adjusting the torque applied to the supply roll, without direct measurement of the roll radius, using angular displacement measurements from an encoder to calculate the roll radii and maintain proper tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to determine supply roll radius, then the system can operate with simple measurement, but the tensioning becomes inconsistent and unreliable for textured polishing articles
Solution Approach 1:
The patent replaces direct mechanical measurement of supply roll radius with an optical encoder system that measures angular displacement and calculates radius indirectly through mathematical relationships, providing more reliable and consistent measurements for textured surfaces
Solution Approach 2:
The patent introduces an encoder wheel as an intermediary measurement device that contacts the take-up roll to measure angular displacement, which then serves as a basis for calculating the supply roll radius without directly measuring the supply roll itself
2Strength
If the supply roll radius is not accurately measured, then the system operation remains simple, but the polishing article experiences breakage, stretching, or wrinkling
Solution Approach 1:
The patent implements a feedback control system where the measured angular displacement from the encoder wheel is used to calculate the supply roll radius, which then determines the appropriate tensioning torque to apply, creating a closed-loop system that maintains proper polishing article tension
Solution Approach 2:
The patent replaces direct physical measurement of supply roll radius with an indirect calculation method using encoder-measured angular displacement and mathematical relationships, achieving higher measurement precision without direct contact with the supply roll
3Reliability
If direct measurement of supply roll radius is used, then the tensioning calculation is straightforward, but the measurement becomes unreliable for next-generation textured polishing articles
Solution Approach 1:
The patent uses the take-up roll and encoder wheel as an intermediary measurement system that indirectly provides supply roll radius information through measured angular displacement and mathematical calculation, avoiding direct measurement issues with textured surfaces
Solution Approach 2:
The patent substitutes direct mechanical radius measurement with an optical encoding system that measures angular displacement and converts it to radius information through calculation, providing reliable measurements for textured polishing articles
Data Source
AI summary
Embodiments of the present disclosure generally provide methods, polishing systems with computer readable medium having the methods stored thereon, to facilitate consistent tensioning of a polishing article disposed on a web-based polishing system. In one embodiment, a substrate processing method includes winding a used portion of a polishing article onto a take-up roll of a polishing system by rotating a first spindle having the take-up roll disposed thereon; measuring, using an encoder wheel, a polishing article advancement length of the used portion of the polishing article wound onto the take-up roll; determining a tensioning torque to apply to a supply roll using the measured polishing article advancement length; and tensioning the polishing article by applying the tensioning torque to the supply roll.