Polishing Apparatus Turn Table Vertical Movement Mechanism
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Solution Overview
Problem
Conventional index system polishing apparatuses face challenges in reducing displacement of the polishing shaft under moment load, affecting wafer quality and productivity due to long polishing shaft lengths and interference with dressing mechanisms, which complicates height adjustments and increases takt time.
Innovation Solution
The introduction of a turn table upward and downward movement mechanism allows for shorter polishing shafts with improved stiffness, enabling parallel rotation and movement of the polishing head and turn tables without interfering with the dressing mechanism, and automatic height adjustment of turn tables based on polishing pad abrasion to maintain dressing effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the polishing head moves upward and downward with a long stroke width to avoid collision with the dressing mechanism, then the polishing shaft length increases, but the stiffness of the polishing shaft decreases and displacement increases under moment load
Solution Approach 1:
Instead of moving the polishing head upward to avoid the dressing mechanism, the invention inverts the approach by moving the turn table downward. This allows the polishing head to maintain a shorter, stiffer shaft configuration while the turn table moves out of the way during dressing operations, eliminating the collision problem without compromising shaft stiffness
Solution Approach 2:
The invention makes the turn table height position dynamic rather than fixed. The turn table can automatically adjust its height position between polishing and dressing operations, allowing it to move downward during dressing to avoid collision with the polishing head, and return to its original position during polishing
2Manufacturing precision
If manual height adjustment of the dressing mechanism is performed to maintain dressing effectiveness, then the dressing effect is maintained, but the takt time increases and productivity decreases
Solution Approach 1:
The turn table is equipped with automatic height adjustment capability that allows it to self-adjust its position based on polishing pad abrasion. This eliminates the need for manual intervention to maintain dressing effectiveness, thereby reducing takt time and improving productivity while maintaining the required dressing quality
Solution Approach 2:
The system implements automatic height adjustment of the turn table based on feedback from polishing pad wear detection. This feedback mechanism enables the turn table to automatically compensate for pad abrasion, maintaining optimal dressing conditions without manual intervention and preventing productivity loss
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 reduces displacement of the polishing shaft during wafer polishing, enhances accuracy, shortens takt time, and improves productivity by eliminating the need for manual height adjustments and reducing variability in dressing effects.
Implementation Method 1
polishing by supplying the polishing agent 107 on the polishing pad 103 from the polishing agent supplying mechanism 108, while respectively rotating the turn table 104 and the polishing head 102 to bring a surface of the wafer W into sliding contact with the polishing pad 103
Data Source
AI summary
A polishing apparatus which is an index system polishing apparatus which includes a polishing head for holding a wafer, a plurality of turn tables to which polishing pads for polishing the wafer are attached, and a loading/unloading stage for loading the wafer to the polishing head or unloading the wafer from the polishing head, and which polishes the wafer while switching the turn tables to be used for polishing the wafer held at the polishing head by causing the polishing head to perform rotation movement, the polishing apparatus including a turn table upward and downward movement mechanism which allows the turn table to move upward and downward. With this polishing apparatus, it is possible to reduce an amount of displacement caused when moment load is applied on the polishing head during polishing.