Reinforcement Ring for Carrier Head Vacuum Sealing
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Solution Overview
Problem
In chemical mechanical polishing, the existing multi-zone carrier heads face challenges in reliably chucking substrates with flatted areas, as the inner vacuum zone often extends beyond the flat, impeding the creation of a sealed vacuum and reducing the reliability of the chucking operation, especially for substrates with diameters of 150 mm or less.
Innovation Solution
A reinforcement ring is integrated into the carrier head, featuring a substantially vertical cylindrical portion and flanges that project inwardly and outwardly at non-zero angles, allowing for a multi-chamber configuration that ensures the flexible membrane remains in contact with the substrate, even when the substrate flat extends beyond the outermost pressure zone, by applying pressure to specific chambers and using vacuum in others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum is drawn on the inner zone of the carrier head to chuck the substrate, then the substrate can be secured to the carrier head, but the flatted area extending beyond the outermost zone interferes with creation of the suction cup, reducing chucking reliability
Solution Approach 1:
The carrier head is divided into multiple pressure zones (inner vacuum zone and outer pressure zone) separated by a reinforcement ring. This segmentation allows independent control of vacuum and pressure regions, enabling reliable chucking even when the flat extends beyond the outermost zone by ensuring the vacuum zone remains sealed and effective.
Solution Approach 2:
The reinforcement ring acts as an intermediary structure between the vacuum zone and pressure zone. It provides a physical barrier that maintains the integrity of the vacuum seal while allowing the flexible membrane to conform to the substrate, preventing interference from the extended flat area.
2Force
If pressure is applied to the outermost zone to push the substrate against the polishing pad, then polishing contact is improved, but the flatted area extending beyond this zone interferes with vacuum sealing
Solution Approach 1:
The carrier head is divided into multiple pressure zones (inner vacuum zone and outer pressure zone) separated by a reinforcement ring. This segmentation allows independent control of vacuum and pressure regions, enabling reliable chucking even when the flat extends beyond the outermost zone by ensuring the vacuum zone remains sealed and effective.
Solution Approach 2:
Different regions of the carrier head are assigned different functions: the inner zone provides vacuum for securement, while the outer zone provides pressure for polishing contact. The reinforcement ring creates a localized boundary that maintains vacuum seal integrity in the inner zone while allowing pressure application in the outer zone, accommodating extended flats without compromising either function.
3Area of stationary object
If the inner vacuum zone extends beyond the outermost pressure zone, then coverage of the substrate is improved, but the flatted area interferes with creation of the suction cup, reducing vacuum effectiveness
Solution Approach 1:
The reinforcement ring acts as an intermediary structure between the vacuum zone and pressure zone. It provides a physical barrier that maintains the integrity of the vacuum seal while allowing the flexible membrane to conform to the substrate, preventing interference from the extended flat area.
Solution Approach 2:
The reinforcement ring creates a localized boundary that maintains vacuum seal integrity in the inner zone while allowing pressure application in the outer zone, accommodating extended flats without compromising either function.
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 enhances the reliability of the chucking operation by maintaining a sealed vacuum and ensuring consistent contact with the substrate, thereby improving the substrate's securement during polishing, particularly for substrates with diameters of 150 mm or less.
Implementation Method 1
pressure can be applied to an outermost zone while vacuum is drawn on an inner zone in order to chuck a substrate to the carrier head
Implementation Method 2
vacuum is drawn on an inner zone in order to chuck a substrate to the carrier head
Data Source
AI summary
A reinforcement ring is for placement in a carrier head to abut an inner surface of a perimeter portion of a flexible membrane. The reinforcement ring includes a substantially vertical cylindrical portion, a first flange projecting inwardly from the bottom of the cylindrical portion, and a second flange projecting outwardly from a bottom of the cylindrical portion. The second flange projects downwardly at a non-zero angle from vertical.