Actuated Polishing Pad Assemblies for Local Substrate Material Removal
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Solution Overview
Problem
The existing chemical mechanical polishing processes struggle to effectively remove materials from local areas of a substrate due to the redistribution of pressure, making it difficult to achieve precise material removal at specific regions.
Innovation Solution
A polishing module with a chuck and actuated polishing pad assemblies that allow for controlled movement in sweep, radial, and oscillating directions, limited to less than half the radius of the chuck, enabling precise material removal from local areas of a substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If carrier head applies differential pressure to local regions of substrate, then material removal is improved at peripheral edges, but substrate stiffness redistributes pressure globally making local pressure application difficult
Solution Approach 1:
The polishing system divides the substrate processing into multiple independent polishing heads positioned at different locations. Each polishing head can be independently actuated to apply pressure to specific regions, preventing global pressure redistribution while achieving local material removal. The segmentation of the polishing function into discrete, controllable units allows precise local control without being affected by substrate stiffness.
Solution Approach 2:
The polishing heads are coupled to actuators that provide dynamic movement in sweep, radial, and oscillating directions. This dynamic capability allows the polishing heads to adapt their position and pressure application in real-time, maintaining local pressure control despite substrate stiffness. The oscillating movement mode specifically helps overcome the smoothing effect by continuously varying the contact points.
2Area of stationary object
If polishing pad assemblies are allowed extensive radial movement, then coverage area is increased, but local polishing control and precision are reduced
Solution Approach 1:
The system employs multiple polishing heads with limited radial movement (less than one-half radius of chuck) positioned at specific locations around the chuck perimeter. Each polishing head is optimized for its specific local region, providing high precision for that area. The combination of multiple localized polishing zones achieves overall coverage while maintaining local precision, as each head focuses its action on a specific region without excessive radial travel.
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 allows for improved local polishing control with minimal dishing or erosion, achieving material thickness removals of 20-200 Angstroms with ±5 Angstroms accuracy, suitable for thickness corrections and edge bevel polishing.
Implementation Method 1
each of the one or more polishing pad assemblies are coupled to an actuator that provides movement of the respective polishing pad assemblies in one or more of a sweep direction, a radial direction, and a oscillating mode relative to the substrate receiving surface
Implementation Method 2
a motor that is coupled to a shaft and a rotor that provides oscillating movement between the polishing pad assembly and the housing
Implementation Method 3
the substrate is retained in a carrier head that urges or presses the backside of the substrate toward a polishing pad
Implementation Method 4
Material is removed globally across the surface of the feature side of the substrate that is in contact with the polishing pad through a combination of chemical and mechanical activity
Data Source
AI summary
A polishing module including a chuck having a substrate receiving surface and a perimeter, and one or more polishing pad assemblies positioned about the perimeter of the chuck, wherein each of the one or more polishing pad assemblies are coupled to an actuator that provides movement of the respective polishing pad assemblies in one or more of a sweep direction, a radial direction, and a oscillating mode relative to the substrate receiving surface and are limited in radial movement to about less than one-half of the radius of the chuck as measured from the perimeter of the chuck.