List of Contents
Air Bag Platen (P-ABP)
The air bag platen in Chemical Mechanical Planarization (CMP) is a flexible, inflatable component integrated into the platen system. Ponda’s air bag platen distributes pressure across the wafer surface in multiple distinct zones, allowing for precise control of planarization forces.
By adjusting pressure in each zone, the air bag ensures uniform polishing, compensating for variations in wafer topography and optimizing material removal for consistent, high-quality results.
| Wafer Diameter | Number of Pressure Zone |
|---|---|
| 100 mm (4 inches) | 3 |
| 150 mm (6 inches) | 4 |
| 200 mm (8 inches) | 5 |
| 300 mm (12 inches) | 6 |
- Air Bags
- Membrane Film
- Platen Film
- Wafer
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Oscillating Platen
The oscillating platen (the process) facilitates a sequential, spiraling, cross-path processing route for the workpiece, resulting in exceptionally good flatness.
Additionally, oscillating platen helps to even out the wear on the plate’s abrasive layer. It’s well understood that in lapping and polishing, the product and the abrasive wear each other down. Workpieces processed without oscillation are confined to a fixed area. If the processed product’s width is narrower than that of the abrasive layer’s unilateral width, prolonged processing could lead to a concave surface on abrasive layer, thereby compromising the machining flatness.
The oscillation modes are also divided into linear oscillation and arc oscillation. Linear oscillation is commonly found in the PDN Light series and PDS Wafer Lapping/Polishing model. Arc oscillation is commonly found in single-platen models such as the PDN Heavy series, Semi-Automatic and Fully Automatic CMP series.
Note: The oscillating platen is an exclusive option available in the single-platen and twin-platen model with pneumatic pressurization unit.
Universal Platen
To control the workpiece’s thickness variation, a universal pressure joint connects the platen to its air cylinder’s spindle. During operation, a pneumatic cylinder applies a consistent vertical force to the platen spindle. At the same time, the cylinder shaft is driven to rotate, allowing the workpiece to undergo finer cross-grinding, resulting in improved precision.
The universal pressure joint, bearing this downward pressure, also accommodates the counterforce exerted by the workpiece. If the workpiece’s surface becomes inclined, the counterforce on the workpiece’s thicker area increases as the joint distributes more of vertical force on this area. Thus removal rate of the area increases, thereby ensuring uniform thickness across the workpiece.
Versatile Clamping
The clamping method is selected based on the wafer’s adhesion methods. There are primarily two types of clamping: direct wafer vacuum clamping and vacuum clamping to a ceramic carrier bonded with wafers. The main distinction lies in the materials and designs used: direct wafer clamping employs a microporous ceramic platen for clamping, whereas clamping to a ceramic carrier involves a metal platen with vacuum grooves.