Eccentric Carrier Mounting for Wafer Flatness
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Solution Overview
Problem
Conventional double side polishing apparatuses face issues with fixed wafer mounting holes, leading to prolonged process times, economic damage from premature replacement of carriers and polishing plates, and reduced wafer flatness due to physical deformation and uneven polishing.
Innovation Solution
A carrier with a variable mounting hole location and dual configuration, comprising a center plate and a circumferential plate of different materials, where the center of the mounting hole is eccentric from the center of the center plate, and the center of the fitting hole is eccentric from the center of the circumferential plate, allowing for adjustable wafer positioning and improved rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed wafer mounting hole location is used in the carrier, then the carrier structure is simple, but the polishing quality deteriorates due to inability to adapt to physical deformation of polishing plates
Solution Approach 1:
The patent applies the dynamics principle by making the mounting hole position adjustable rather than fixed. The carrier allows the mounting hole to be repositioned to different locations on the carrier plate, enabling adaptation to the dynamic physical deformation of polishing plates during repeated use. This dynamic adjustment capability resolves the contradiction by allowing the simple carrier structure to maintain polishing quality through adaptability.
Solution Approach 2:
The patent applies parameter changes by varying the position parameter of the mounting hole on the carrier. By changing the location parameter of where the wafer is mounted, the system can compensate for the physical deformation of polishing plates that occurs over time. This allows the same carrier to maintain optimal polishing conditions without requiring complex structural modifications.
2Manufacturing precision
If carriers and polishing plates are replaced frequently to maintain quality, then wafer flatness is maintained, but process time increases and economic damage occurs
Solution Approach 1:
The patent applies preliminary action by pre-configuring the carrier with an adjustable mounting hole position system. Instead of replacing carriers when deformation occurs, the system allows operators to pre-adjust the mounting hole position to compensate for known or anticipated polishing plate deformation patterns. This prevents quality deterioration before it happens, eliminating the need for frequent replacements and reducing process time losses.
3Productivity
If polishing is performed at great pressure for considerable time, then polishing effectiveness is improved, but physical deformation of polishing plates increases
Solution Approach 1:
The patent applies feedback by using the adjustable mounting hole position as a compensatory mechanism for polishing plate deformation. As polishing plates deform under repeated high-pressure operation, the mounting hole position on the carrier can be adjusted to compensate for this deformation, maintaining optimal polishing conditions. This feedback loop allows sustained high-pressure polishing without permanent quality deterioration, resolving the contradiction between productivity and plate stability.
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 active adaptation to dynamic polishing factors, extends the life cycle of carriers, reduces wear and replacement costs, and maintains high wafer flatness and stability, enhancing productivity and economic efficiency.
Implementation Method 1
a sun gear and an internal gear engaged with the gear part of the circumferential plate to transmit a rotational force to the plurality of carriers
Implementation Method 2
A frictional force is generated by a rotational motion between the wafer and the polishing pads of the upper and lower polishing plates
Implementation Method 3
the center of the mounting hole is eccentric from the center of the center plate, and the center of the fitting hole is eccentric from the center of the circumferential plate
Data Source
AI summary
A double side polishing apparatus comprises an upper polishing plate and a lower polishing plate for polishing both sides of a wafer; a plurality of carriers, each including a center plate and a circumferential plate, the center plate having a mounting hole where the wafer is mounted, the circumferential plate having a fitting hole where the center plate is fitted and a gear part formed along the outer periphery thereof, the center of the mounting hole being eccentric from the center of the center plate, the center of the fitting hole being eccentric from the center of the circumferential plate; and a sun gear and an internal gear engaged with the gear part to transmit a rotational force to the plurality of carriers, wherein a fitting direction of a center plate into a fitting hole is adjustable for at least two carriers among the plurality of carriers.