CMP Apparatus Coaxial Transfer for Large Glass Substrates
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Solution Overview
Problem
The existing substrate polishing technologies face challenges with large-size glass substrates, including deformation, breakage, contamination, excessive heat generation, high slurry consumption, and difficulty in compact and cost-effective design, especially when using CMP apparatuses for polishing and cleaning.
Innovation Solution
A substrate polishing apparatus with a coaxial substrate transfer mechanism, independent support systems for device areas, tilting mechanisms for easy substrate removal, and a polishing table with cooling fins and slurry outlets to manage heat and slurry usage, along with a gas ejection system for smooth substrate release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large-size glass substrate is held against the substrate holder for polishing, then the substrate can be polished, but the substrate is highly liable to be deformed or bent due to its thin structure and large size
Solution Approach 1:
The substrate holder is divided into multiple independent suction cups arranged in an array, allowing localized control of holding force across different regions of the large substrate. This segmentation enables uniform distribution of holding force, preventing deformation while maintaining the substrate flat against the holder surface during polishing.
Solution Approach 2:
The substrate holder uses vacuum suction through multiple suction cups to hold the substrate. The pneumatic system provides uniform distributed holding force across the entire substrate surface, preventing local stress concentrations that would cause deformation or bending of the thin large-size substrate.
2Manufacturing precision
If a large-size glass substrate is polished with a large polishing pad, then high surface planarization can be achieved, but a large amount of frictional heat is produced
Solution Approach 1:
A gas ejection nozzle is positioned near the polishing interface to eject gas between the substrate and polishing pad. This gas layer acts as a thermal barrier, reducing heat transfer from the friction interface to the substrate while maintaining the polishing contact, thus controlling temperature rise during large-area polishing.
Solution Approach 2:
The ejected gas creates a protective atmosphere at the polishing interface, serving as a thermal insulator that prevents excessive heat generation and transfer to the substrate, while allowing the mechanical polishing action to continue effectively.
3Reliability
If a large-size glass substrate is held under vacuum suction, then the substrate can be securely held, but the substrate is highly difficult to release from the attracting surface in its entirety in one direction
Solution Approach 1:
The array of independently controllable suction cups allows selective release of substrate from different regions. By controlling individual suction cups or groups of suction cups, the substrate can be progressively released from one end to the other, enabling easy removal without requiring forceful extraction from the entire surface simultaneously.
Solution Approach 2:
The suction cup array system allows dynamic control of vacuum application to different regions of the substrate. During release, the vacuum can be progressively reduced or removed from specific areas, enabling controlled and easy substrate removal without damage, while maintaining secure holding during the polishing operation.
4Manufacturing precision
If a large-size glass substrate is polished, then high surface planarization is achieved, but a large amount of slurry is required which increases process cost
Solution Approach 1:
The gas ejection system modifies slurry distribution and removal at the polishing interface. By ejecting gas, the system controls slurry flow and prevents excessive slurry accumulation, enabling more efficient slurry utilization and reducing overall consumption while maintaining effective polishing action across the large substrate surface.
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
The solution enables reliable polishing and cleaning of large-size glass substrates with improved planarization, reduced risk of breakage, and efficient slurry use, while allowing for a more compact and cost-effective apparatus design.
Implementation Method 1
a plurality of suction cups (26) for holding the substrate (G) by vacuum suction
Implementation Method 2
a polishing pad (61) for polishing the substrate (G) held by the head (40)
Implementation Method 3
a polishing table (60) having a plurality of cooling fins (63)
Implementation Method 4
a gas ejection nozzle (86) for ejecting a gas into a gap between the substrate (G) and the head (40)
Data Source
AI summary
A substrate polishing apparatus includes a substrate holding mechanism having a head for holding a substrate to be polished, and a polishing mechanism including a polishing table with a polishing pad mounted thereon. The substrate held by the head is pressed against the polishing pad on the polishing table to polish the substrate by relative movement of the substrate and the polishing pad. The substrate polishing apparatus also includes a substrate transfer mechanism for delivering the substrate to be polished to the head and receiving the polished substrate. The substrate transfer mechanism includes a substrate to-be-polished receiver for receiving the substrate to be polished, and a polished substrate receiver for receiving the substrate which has been polished.