Polishing Pad Cleaning via Substrate Transfer Idle Time
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Solution Overview
Problem
Conventional polishing apparatuses face challenges in maintaining high throughput while effectively cleaning the polishing pad to prevent abrasive particle agglomeration, leading to scratches on semiconductor wafers, as existing methods either prolong the cleaning time or require cumbersome time settings.
Innovation Solution
A method and apparatus that utilize idle time during substrate transferring processes to perform pad cleaning, starting after the completion of the polishing recipe and terminating when the next substrate is detected, allowing for variable and extended cleaning times without altering the polishing recipe or setting specific cleaning times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cleaning of the polishing pad is performed by extending cleaning time or setting specific cleaning time, then abrasive particles are removed effectively, but throughput is reduced due to additional time allocation
Solution Approach 1:
The polishing pad is cleaned in advance during the substrate transferring process before the next polishing operation begins. The cleaning operation is performed preliminarily by ejecting cleaning fluid onto the polishing pad while the substrate is being transferred, thereby removing abrasive particles before they can cause scratches during the subsequent polishing process.
Solution Approach 2:
The cleaning operation is made dynamic by adjusting the cleaning fluid ejection timing and duration based on the substrate transfer process status. The cleaning fluid is ejected during the substrate transferring process, and the cleaning operation adapts to the variable timing of substrate transfers, allowing thorough cleaning without fixed time allocation that would reduce throughput.
2Productivity
If cleaning fluid is ejected onto the polishing pad during idle time, then abrasive particles are removed without affecting polishing throughput, but cleaning effectiveness may be reduced compared to extended cleaning time
Solution Approach 1:
The cleaning action continues effectively during the substrate transferring process by maintaining continuous ejection of cleaning fluid onto the polishing pad. The cleaning operation is performed continuously throughout the substrate transfer duration, ensuring that abrasive particles are removed without interruption to the polishing throughput while maximizing the utilization of idle time.
Solution Approach 2:
The cleaning operation is performed in advance during the substrate transferring process, preparing the polishing pad for the next polishing operation. By ejecting cleaning fluid onto the polishing pad during the transfer process, abrasive particles are removed preliminarily before they can contaminate the next substrate, ensuring polishing quality without extending the polishing cycle time.
3Productivity
If cleaning is performed without setting specific cleaning time, then throughput is maintained, but cleaning effectiveness may be insufficient to prevent abrasive particle agglomeration
Solution Approach 1:
The cleaning operation incorporates feedback by detecting the presence and position of substrates during the transferring process. The cleaning fluid ejection is controlled based on substrate transfer status, ensuring that cleaning is performed for an appropriate duration that is sufficient to remove abrasive particles while adapting to the actual process conditions, thereby preventing scratch-causing agglomeration without compromising throughput.
Solution Approach 2:
The cleaning duration and intensity are made dynamic, adjusting automatically based on the substrate transfer process timing. The cleaning operation adapts to the variable duration of substrate transfers, ensuring sufficient cleaning effectiveness to prevent abrasive particle agglomeration while maintaining high throughput by utilizing the actual idle time available during each transfer cycle.
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 maximizes idle time for pad cleaning, ensuring thorough removal of abrasive particles and preventing scratches, while maintaining high throughput by integrating cleaning into the substrate transfer process without additional time allocations.
Implementation Method 1
a polishing liquid (slurry) containing abrasive particles, such as silica (SiO2), ceria (CeO2) or the like, therein is supplied onto a polishing pad, a substrate such as a semiconductor wafer is brought into sliding contact with the polishing pad and polished
Implementation Method 2
a pad cleaning process for removing foreign matters on the polishing pad by ejecting a cleaning fluid onto the polishing pad
Data Source
AI summary
A polishing method is used for polishing a surface of a substrate such as a semiconductor wafer. The polishing method includes a polishing process for polishing a surface of the substrate in accordance with a preset polishing recipe, a pad cleaning process for removing foreign matters on the polishing pad by ejecting a cleaning fluid onto the polishing pad, and a substrate transferring process in which the polished substrate is removed from the top ring at a substrate transferring position, a subsequent substrate to be polished is loaded onto the top ring, and then the top ring holding the subsequent substrate to be polished is returned to the polishing table. The pad cleaning process is started after the completion of the polishing recipe is detected, and the pad cleaning process is terminated by detecting a position of the subsequent substrate to be polished which is undergoing the substrate transferring process.