CMP Pad Conditioner Force Feedback for Stable Polishing
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Solution Overview
Problem
Existing Chemical Mechanical Polishing (CMP) apparatuses face challenges in maintaining consistent downward force applied by the pad conditioner, leading to instability in polishing rate and debris removal efficiency, which can result in defects on wafers and reduced polishing pad lifespan.
Innovation Solution
A measurement tool is integrated to monitor and dynamically adjust the downward force of the pad conditioner during the CMP process, ensuring it remains within predetermined limits, and a self-cleaning mechanism is implemented using a washing solution supply system to maintain the cleanliness of the polishing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pad conditioner applies downward force to remove debris from the polishing pad, then debris removal efficiency is improved, but the downward force becomes unstable over time, leading to inconsistent polishing rate and potential wafer defects
Solution Approach 1:
A measurement tool is integrated into the pad conditioner to monitor the actual downward force in real-time. The system compares the measured force against a target value and automatically adjusts the downward force application to maintain stability within a specified range, thereby resolving the instability issue while preserving debris removal efficiency
Solution Approach 2:
The patent replaces purely mechanical force application with a controlled system that uses a measurement tool and automated adjustment mechanism. This substitution allows for precise monitoring and regulation of downward force, transforming an unstable mechanical process into a controlled, stable process
2Reliability
If the pad conditioner operates continuously to maintain polishing surface quality, then polishing consistency is improved, but the polishing pad lifespan is reduced due to excessive wear
Solution Approach 1:
The system dynamically adjusts the downward force of the pad conditioner based on real-time measurements rather than applying constant force. By modulating the force within a target range, the system maintains polishing consistency when needed while reducing unnecessary wear, thereby extending polishing pad lifespan
Solution Approach 2:
The patent changes the parameter of downward force from a fixed value to a dynamically adjusted value within a specified range. This parameter change allows the system to optimize between polishing consistency and pad wear by applying only the necessary force at any given moment
Data Source
AI summary
A chemical mechanical polishing (CMP) apparatus is provided, including a polishing pad and a polishing head. The polishing pad has a polishing surface. The polishing head is configured to hold a wafer in contact with the polishing surface during the polishing process. The polishing head includes a retaining ring, at least one fluid channel, and a vacuum pump. The retaining ring is arranged along the periphery of the polishing head and configured to retain the wafer. The at least one fluid channel is provided inside the polishing head, wherein the retaining ring includes a bottom surface facing the polishing surface and a plurality of holes in fluid communication with the bottom surface and the at least one fluid channel. The vacuum pump is fluidly coupled to the at least one fluid channel.