Flexure-Mounted CMP Pad Carrier for Radial Polishing Uniformity
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Solution Overview
Problem
Chemical mechanical polishing processes often result in thickness non-uniformity and radially non-uniform polishing across the substrate surface, leading to under-polished regions and reduced throughput.
Innovation Solution
A chemical mechanical polishing system utilizing a flexure-mounted pad carrier assembly with lateral actuators and a pad carrier actuator to apply downward pressure, allowing for localized polishing and simultaneous pad conditioning, enabling nearly 360° coverage of the substrate with arcuate pads that compensate for radial non-uniformity while maintaining high throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the polishing pad is fixed to a rigid support structure, then structural stability is maintained, but the system complexity increases and substrate transfer becomes difficult
Solution Approach 1:
The pad carrier is mounted on flexures instead of a rigid support structure. The flexures provide the necessary stability and positioning while allowing controlled movement and adjustment. This flexible mounting reduces system complexity by eliminating the need for complex rigid support mechanisms while maintaining pad carrier stability during polishing operations.
2Manufacturing precision
If the polishing pad contacts the entire substrate surface, then full surface polishing is achieved, but throughput is reduced due to inability to perform location specific polishing
Solution Approach 1:
The arcuate polishing pads are configured to contact only specific radial zones of the substrate rather than the entire surface. The lateral actuators enable precise positioning of each pad segment to target specific areas requiring polishing, such as edge regions. This localized polishing approach maintains manufacturing precision for critical zones while enabling faster processing by avoiding unnecessary polishing of already-planar areas, thereby increasing throughput.
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 system achieves improved substrate flatness and finish by reducing non-uniform polishing, especially at the edges, and allows for efficient substrate transfer below the polishing level, increasing throughput and reducing operating costs by decoupling the polishing pad from the pressurizable chamber.
Implementation Method 1
a flexure having a first end secured to the support and a second end
Implementation Method 2
a lateral actuator coupled the support to cause the support to move along the radial direction
Implementation Method 3
a pad carrier actuator secured to the arm to apply a downward pressure to a top of the flexure
Implementation Method 4
a motor to rotate the chuck about a first axis
Data Source
AI summary
A chemical mechanical polishing method includes transferring a substrate onto a chuck supported by a drive shaft when the chuck is located at a first height, raising the chuck to a second height greater than the first height such that a top surface of the substrate is in contact with at least one polishing pad, polishing the substate by the at least one polishing pad, lowering, the chuck to a third height lower than the second height, and transferring the substrate off of the chuck.