Polishing Apparatus Flow Channel Clogging Detection and Cleaning
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Solution Overview
Problem
Polishing apparatuses face clogging issues in flow channels due to drying and deposition of polishing solutions, leading to decreased performance and lack of detection mechanisms for clogging.
Innovation Solution
Incorporating a switching device to alternate between polishing and cleaning solutions, a sensor to detect pressure or flow rate changes, and a control device to initiate cleaning and clogging detection processes when a predetermined number of substrates is polished, along with a flow rate adjusting device to enhance pressure detection downstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polishing solution is continuously supplied to the polishing machine, then polishing performance is maintained, but clogging occurs in the flow channel due to drying and deposition
Solution Approach 1:
The system periodically switches between polishing solution supply and cleaning solution supply based on the number of substrates polished. After a predetermined number of substrates are polished, the cleaning solution is supplied to flush the flow channel, preventing clogging while maintaining polishing performance during normal operation.
Solution Approach 2:
A cleaning solution is introduced as an intermediary substance to prevent clogging. The cleaning solution flows through the flow channel to remove deposits and prevent polishing solution from drying and clogging the channel, acting as a mediator between the polishing process and the flow channel maintenance.
2Reliability
If cleaning solution is supplied to clean the flow channel, then clogging is prevented, but polishing process is interrupted
Solution Approach 1:
The cleaning operation is performed periodically after a predetermined number of substrates are polished, rather than continuously. This periodic cleaning minimizes interruption to the polishing process while still preventing clogging, thereby balancing productivity and flow channel reliability.
Solution Approach 2:
The cleaning solution is supplied in advance before clogging completely blocks the flow channel. By detecting the number of substrates polished and initiating cleaning at the appropriate time, the system prevents severe clogging while minimizing interruption to the polishing process.
3Productivity
If discharge nozzle with narrow discharge hole is used, then polishing solution flow is controlled, but clogging occurs more frequently due to solution remaining in the discharge hole
Solution Approach 1:
The cleaning solution acts as an intermediary that flows through the narrow discharge hole to prevent polishing solution from remaining and drying. The cleaning solution's flow flushes out any residual polishing solution from the discharge hole, preventing clogging while allowing the narrow hole to maintain its flow control function.
Solution Approach 2:
The system uses hydraulic flow of cleaning solution to clear the discharge hole. By supplying cleaning solution at sufficient flow rate and pressure, the system uses fluid dynamics to prevent clogging in the narrow discharge hole, maintaining both flow control and clogging resistance.
4Device complexity
If no clogging detection mechanism is provided, then device complexity is reduced, but clogging cannot be detected until complete blockage occurs
Solution Approach 1:
A sensor detects the flow rate or pressure of the cleaning solution, providing feedback to the control device. Based on this feedback, the control device determines whether clogging has occurred and can notify the user or automatically adjust operations, enabling timely detection before complete blockage.
Solution Approach 2:
The system replaces complex mechanical clogging detection mechanisms with simpler sensor-based detection. By using sensors to monitor cleaning solution flow rate or pressure, the system achieves reliable clogging detection with reduced mechanical complexity.
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
Effectively prevents clogging by cleaning the flow channel with a cleaning solution and detects clogging occurrences, ensuring continued polishing performance and preventing substrate polishing when high clogging is detected.
Implementation Method 1
a sensor detecting a pressure or a flow rate of the cleaning solution flowing in the flow channel
Implementation Method 2
a sensor detecting a pressure or a flow rate of the cleaning solution flowing in the flow channel
Implementation Method 3
a flow rate adjusting device disposed at a position downstream from the switching device in the flow channel and configured to adjust a flow rate of the cleaning solution flowing in the flow channel to a predetermined range
Implementation Method 4
since the flow rate adjusting device is provided, a pressure at a position downstream from the flow rate adjusting device in the flow channel can be effectively increased when clogging has occurred in the flow channel
Data Source
AI summary
A polishing apparatus 1 includes a control device 90. The control device 90 performs: a cleaning process of causing a cleaning solution to flow in a flow channel 70a and then causing a polishing solution to flow in the flow channel 70a when the number of substrates Wf polished by a polishing machine 10 reaches a predetermined number; and a clogging detecting process of detecting whether clogging has occurred in the flow channel based on a pressure or a flow rate of the cleaning solution detected by sensors 60 and 61 when the cleaning solution flows in the flow channel.