Wafer Processing Turntable with Intermittent Chuck Rotation
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Solution Overview
Problem
Existing wafer grinding methods face challenges in maintaining precise positioning of processing tools with respect to the wafer, leading to potential damage and irregularities during the formation of circular recesses and annular lands, especially when transitioning between coarse, finishing, and precision grinding processes.
Innovation Solution
A processing apparatus with a turntable and multiple chuck tables that allows for intermittent rotation, enabling precise positioning of annular grinding wheels and polishing pads to maintain continuous contact with the wafer, ensuring appropriate tool placement and preventing wafer shifting during different processing stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple processing tools (coarse grindstones, finishing grindstones, precision grindstones or polishing pad) are used to process the wafer, then the surface finish quality is improved, but the positioning accuracy of the tools with respect to the wafer deteriorates
Solution Approach 1:
The patent employs a turntable that can rotate to different positions, allowing dynamic repositioning of multiple chuck tables. Each chuck table is equipped with independently controllable processing tools that can be dynamically selected and positioned. The turntable rotation mechanism enables smooth transitions between different processing stages while maintaining precise positioning through controlled movement to predetermined angular positions.
Solution Approach 2:
The processing system is divided into multiple independent chuck tables (at least four), each capable of holding a wafer and being positioned at different locations around the turntable. Each chuck table can be independently controlled to rotate and position its processing tools. This segmentation allows different processing tools to be isolated on separate tables, preventing interference and maintaining positioning accuracy for each tool type.
2Stability of the object's composition
If the wafer is held on a chuck table during processing, then the wafer stability is improved, but the wafer may shift position on the holding surface, causing damage or irregularities
Solution Approach 1:
The chuck tables are designed with dynamic rotation capability, allowing them to rotate to precise angular positions while maintaining wafer contact. The turntable provides a stable reference frame that rotates in controlled increments, enabling the chuck table to present different sides or positions of the wafer to processing tools without losing overall stability. This dynamic positioning prevents wafer shifting while enabling multi-stage processing.
3Manufacturing precision
If multiple processing mechanisms are used in sequence, then the processing quality is improved, but the device complexity increases
Solution Approach 1:
Each chuck table is designed as a multi-functional unit that can perform multiple processing operations. The chuck tables are equipped with both grinding wheels and polishing pads that can be selectively engaged. The turntable structure serves multiple functions: holding multiple chuck tables, providing rotational positioning, and enabling sequential access to different processing mechanisms. This universality reduces the need for separate dedicated equipment for each processing step.
Solution Approach 2:
The patent combines multiple processing mechanisms (coarse grinding, finishing grinding, precision grinding/polishing) into a single integrated apparatus centered around the turntable with multiple chuck tables. The horizontal moving mechanisms for different grinding wheels are merged into a coordinated system that operates from the same base structure. This consolidation allows sequential processing while sharing common support infrastructure, reducing overall device complexity compared to separate standalone machines.
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
Enables effective and damage-free processing of wafers by maintaining continuous contact and precise positioning of processing tools, ensuring smooth transitions between coarse, finishing, and precision grinding steps, thereby achieving high-quality surface finishes without shifting the wafer on the holding surface.
Implementation Method 1
a first processing mechanism for grinding the wafer held on one of the holding surfaces with a first annular grinding wheel to form a circular recess in a central portion of the wafer
Implementation Method 2
a third processing mechanism for grinding the bottom of the circular recess in the wafer held on the holding surface with a third annular grinding wheel or polishing an upper surface of the wafer with a first polishing pad
Data Source
AI summary
A processing apparatus includes a rotatable turntable and four chuck tables disposed on the turntable. When the turntable with the four chuck tables disposed thereon is intermittently turned about its central axis, the wafer held on each of the chuck tables is moved to and positioned in a first processing position, a second processing position, and a third processing position where the wafer is processed. Three types of processing processes are able to be carried out on the wafers without the wafers being spaced from holding surfaces of the chuck tables.