Double Side Polisher Platen Parallelism Control
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Solution Overview
Problem
Conventional polishing machines for semiconductor wafers suffer from surface flatness issues due to pad wear, leading to 'doming' or 'dishing' of the wafer surfaces, which necessitates frequent pad replacement and maintenance, increasing operational costs and downtime.
Innovation Solution
A double side polishing apparatus featuring a platen with a reaction plate, polishing plate, and bladder system that allows for adjustable internal pressure to deform the polishing plate, maintaining surface flatness by controlling the gap between the platen and the wafer carrier, thereby extending the life of the polishing pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing machines are used with rotating polishing pads, then wafer surfaces can be polished, but pad wear causes surface flatness to degrade leading to doming or dishing
Solution Approach 1:
The polishing pad is mounted on a platen that can dynamically adjust its curvature through a bladder system. The bladder can be pressurized to change the pad's shape from flat to curved, allowing compensation for wear-induced flatness degradation and prevention of doming or dishing effects
Solution Approach 2:
The system changes the physical parameter of the polishing pad by altering its curvature through bladder pressurization. This parameter change allows the pad to maintain effective polishing geometry despite wear, extending its usable life while preserving surface flatness
2Manufacturing precision
If polishing pads are replaced frequently to maintain surface flatness, then manufacturing precision is improved, but operational costs and downtime increase
Solution Approach 1:
The dynamically adjustable platen allows continuous operation without pad replacement by compensating for wear in real-time through bladder pressurization, eliminating maintenance downtime while maintaining surface flatness
Solution Approach 2:
The system performs self-maintenance by automatically compensating for pad wear through the bladder mechanism, eliminating the need for external intervention (pad replacement) and reducing maintenance costs
3Manufacturing precision
If polishing pads are replaced frequently to maintain surface flatness, then manufacturing precision is improved, but operational costs increase
Solution Approach 1:
The dynamic adjustment capability eliminates the recurring cost of pad replacements while maintaining surface flatness, reducing operational costs without sacrificing manufacturing precision
Solution Approach 2:
By changing the pad curvature parameter through bladder pressurization, the system extends pad life and eliminates replacement costs while maintaining the surface flatness required for high-precision manufacturing
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 apparatus effectively inhibits surface irregularities, extends the useful life of the polishing pad, and reduces maintenance time, improving wafer yield and product tolerances while minimizing pad replacement costs.
Implementation Method 1
A flatness of the polished surface of the wafer is determined. An internal pressure within the bladder is adjusted to deflect the polishing plate with respect to the wafer carrier for improving flatness of the polished surface.
Implementation Method 2
The bladder is connected with the polishing plate for deforming the polishing plate with respect to the bottom surface of the reaction plate.
Data Source
AI summary
A platen for polishing a surface of a wafer has a reaction plate, a polishing plate, and a bladder. The reaction plate has a top and bottom surface, and defines a longitudinal axis. The polishing plate is positioned coaxially with the reaction plate. The polishing plate has a second top surface and a second bottom surface. The second top surface is adjacent to the bottom surface of the reaction plate. The bladder is coaxially located along a radially outer portion of either the top or bottom surface of the reaction plate. The bladder is connected with the polishing plate and able to expand to deform the polishing plate with respect to the bottom surface of the reaction plate.