Polishing Pad Vacuum Cleaning for CMP Debris Removal
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Solution Overview
Problem
Current polishing pad conditioning methods fail to effectively remove processing debris, leading to unevenness and clogging, which reduces the pad's ability to properly planarize substrates during chemical mechanical planarization processes.
Innovation Solution
An apparatus and method utilizing a vacuum system to clean the polishing pad by rotating it, spraying debris-laden areas with high-pressure water, and then vacuuming the debris downstream from the conditioning process, ensuring efficient removal of particles and maintaining pad porosity and flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current conditioning methods are used to condition the polishing pad surface, then the polishing surface roughness and porosity are maintained, but processing debris is not effectively removed, leading to clogging and unevenness
Solution Approach 1:
The cleaning process is segmented into distinct functional zones: a conditioning zone that maintains pad surface properties, a spray zone that lifts debris using high-pressure fluid, and a vacuum zone that removes debris. This segmentation allows each zone to perform its specific function optimally without interfering with others, solving the contradiction between maintaining surface consistency and removing debris.
Solution Approach 2:
A spray medium (fluid) is introduced as an intermediary between the conditioning process and debris removal. The spray lifts debris from the pad surface by creating fluid dynamics that dislodge particles, serving as a mediator that transitions debris from a adhered state to a removable state without directly contacting or damaging the pad surface.
2Manufacturing precision
If conditioning is performed to maintain pad porosity, then the pad's ability to planarize substrate is preserved, but debris generated during conditioning and polishing accumulates on the surface
Solution Approach 1:
The spray cleaning action is positioned upstream of the vacuum removal in the debris elimination sequence. The spray performs preliminary action by lifting and loosening debris from the pad surface before the vacuum fully removes it, making the subsequent vacuuming more effective and ensuring thorough debris removal while preserving pad porosity.
Solution Approach 2:
The cleaning system operates continuously during pad rotation, with the spray and vacuum functioning simultaneously as the pad passes through their respective zones. This continuous action ensures debris is removed as it accumulates, preventing clogging and maintaining consistent substrate planarization quality throughout the polishing process.
3Productivity
If high-pressure spray is used to lift debris, then debris removal effectiveness is improved, but additional cleaning step time is required
Solution Approach 1:
The spray cleaning and vacuum removal functions are merged into a single integrated cleaning station where both actions occur simultaneously as the pad rotates through the zone. This combination eliminates sequential timing delays, as the spray lifts debris while the vacuum concurrently removes it, improving debris removal efficiency without proportionally increasing total cleaning time.
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 effectively removes debris and maintains the polishing pad's surface consistency, enhancing substrate planarization and reducing downtime by ensuring a clean surface for subsequent processing.
Implementation Method 1
vacuuming the debris from the polishing pad surface downstream from where the condition occurs
Implementation Method 2
vacuuming the debris
Implementation Method 3
spraying the polishing pad surface to lift debris from the conditioned polishing pad surface
Data Source
AI summary
In one embodiment, a method for cleaning a surface of a polishing pad includes conditioning the polishing pad surface and rotating the conditioned polishing pad surface. The method also includes spraying the polishing pad surface to lift debris from the conditioned polishing pad surface. The method further includes vacuuming the debris from the polishing pad surface downstream from where the condition occurs, wherein downstream is defined by a rotational direction of the polishing pad. In another embodiment, a processing station including a rotatable platen, a substrate carrier head, a polishing fluid delivery system, a conditioner, a spray nozzle, and a vacuum system is provided. The conditioner is disposed between the substrate carrier head and the spray nozzle. The vacuum system is configured to vacuum the polishing pad surface. The vacuum system is downstream from the conditioner, defined by a rotation of the platen.