Channel-Free Carrier Ring with Curved Grooves for CMP Slurry Flow
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Solution Overview
Problem
Conventional CMP processes with carrier rings having channels suffer from reduced slurry utilization and effectiveness, leading to suboptimal polishing performance and increased costs, as they fail to maximize the removal rate and wafer yield.
Innovation Solution
The use of a polishing pad with curved-radial grooves in combination with a channel-free carrier ring, where the carrier ring presses against the pad to direct the slurry through the grooves and beneath the carrier, promoting efficient slurry flow to the substrate, thereby increasing the removal rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier rings with channels are used to deliver slurry, then slurry delivery to substrate is enabled, but slurry utilization efficiency decreases and polishing performance deteriorates
Solution Approach 1:
The invention extracts and eliminates the channel structure from the carrier ring, transitioning to a channel-free design. This removal of the harmful channel structure prevents slurry loss through carrier ring channels and redirects slurry flow through the polishing pad grooves to the substrate, thereby improving slurry utilization efficiency and polishing performance
Solution Approach 2:
The invention implements localized slurry delivery by creating specific groove patterns in the polishing pad that direct slurry flow precisely to the substrate contact area. The grooves are strategically positioned and configured to ensure slurry is delivered exactly where needed on the substrate surface, maximizing polishing effectiveness while minimizing overall slurry consumption
2Productivity
If conventional groove patterns are used in polishing pads, then slurry flow is provided, but removal rate is insufficient and polishing performance is suboptimal
Solution Approach 1:
The invention segments the polishing pad surface into distinct groove regions with different orientations and configurations. Multiple groove sets are arranged in specific patterns (e.g., radial, concentric, spiral) to create optimized slurry flow paths that enhance removal rate. The segmented groove design allows different regions to perform different functions in slurry distribution and substrate contact
Solution Approach 2:
The invention employs curved and spiral groove patterns instead of straight linear grooves. The curved groove configurations follow radial and concentric paths that better match the rotational motion of the polishing system, improving slurry flow dynamics and maintaining consistent contact between the polishing pad and substrate throughout the polishing cycle, thereby enhancing removal rate
3Manufacturing precision
If carrier ring channels are used for slurry delivery, then slurry reaches substrate, but wafer-to-wafer non-uniformity increases and polishing uniformity deteriorates
Solution Approach 1:
The invention removes the channel structure from the carrier ring entirely, eliminating the source of non-uniform slurry distribution. The channel-free carrier ring design prevents the squeegee effect that causes slurry to be swept away from the substrate, thereby improving wafer-to-wafer polishing uniformity and reducing non-uniformity variations
Solution Approach 2:
The invention introduces the polishing pad groove structure as an intermediary mechanism for slurry delivery. Instead of relying on carrier ring channels, the grooves in the polishing pad act as the primary slurry distribution network, providing more controlled and uniform slurry flow to the substrate surface, which improves polishing uniformity across wafers
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 significantly enhances the removal rate by up to 84% and reduces wafer-to-wafer non-uniformity, improving polishing performance and tool throughput while minimizing slurry loss.
Implementation Method 1
The polishing pad and carrier fixture rotate in opposite directions at different linear velocities
Implementation Method 2
the channel-free surface of the carrier fixture presses against the polishing pad to impede flow of the polishing medium into the substrate
Implementation Method 3
the curved-radial grooves traverse the carrier fixture to promote flow of the polishing medium to the substrate
Implementation Method 4
The wafer surface is polished and made planar by chemical and mechanical action of the polishing layer and polishing medium on the surface
Data Source
AI summary
The invention provides a method for polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium with a polishing pad. The substrate is fixed within a carrier fixture having a channel-free surface. The method comprises securing the substrate in the carrier fixture with the channel-free surface adjacent and parallel to a polishing surface of the polishing pad. The polishing pad has multiple grooves with high-rate paths. The method includes applying polishing medium to the polishing pad adjacent the carrier fixture; and rotating the polishing pad and carrier fixture to polish the substrate with the polishing pad and the polishing medium wherein the channel-free surface of the carrier fixture presses against the polishing pad to impede flow of the polishing medium into the substrate and the high-rate groove paths traverse the carrier fixture to promote flow of the polishing medium to the substrate.