Integrated Slurry Mixer-Dispenser for CMP Uniformity
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes face challenges in achieving precise control of polishing thickness and uniformity across semiconductor wafers due to variations in slurry composition and removal rates, leading to non-uniform film thickness and potential defects like metal corrosion and underpolish.
Innovation Solution
An integrated slurry mixer-dispenser system that continuously adjusts the slurry mixture ratio in real-time based on torque changes detected during the polishing process, using mass flow controllers to maintain optimal removal rates and prevent surfactant accumulation, ensuring uniformity and preventing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional slurry dispensing systems are used, then the system structure is simple, but the slurry composition varies leading to non-uniform polish rate and film thickness
Solution Approach 1:
The patent combines the slurry mixing function and dispensing function into a single integrated unit. The mixer-dispenser receives multiple slurry components, mixes them in controlled proportions, and dispenses the mixed slurry onto the polishing pad through a unified system, ensuring consistent slurry composition and uniform polish rate across the wafer surface.
Solution Approach 2:
The system dynamically adjusts the composition parameters of the slurry by varying the flow rates of different slurry components. Mass flow controllers regulate the proportion of each component entering the mixer, allowing real-time optimization of slurry properties to maintain uniform polish rate and prevent defects like metal corrosion and underpolish.
2Manufacturing precision
If fixed slurry composition is used, then the process is simple to control, but the removal rate becomes non-uniform across the wafer
Solution Approach 1:
The system incorporates sensors that monitor the polish rate and slurry composition in real-time during the CMP process. This feedback information is fed back to the control system, which automatically adjusts the mass flow controllers to modify the slurry mixture ratio, ensuring uniform removal rate across the wafer surface and maintaining high intra-wafer uniformity.
Solution Approach 2:
The slurry composition is transformed from a static, fixed formulation to a dynamic, adjustable mixture. The system continuously varies the proportions of different slurry components based on real-time process conditions, enabling adaptive control of the removal rate to achieve uniform polishing across the entire wafer surface.
3Productivity
If high slurry flow rate is used, then the removal rate increases, but surfactant accumulation occurs causing defects
Solution Approach 1:
The system optimizes the concentration parameters of surfactants and other chemical components in the slurry mixture. By precisely controlling the flow rates of different components, the system maintains surfactant levels within an optimal range that enables effective polishing at high removal rates while preventing surfactant accumulation that would cause metal corrosion and other defects.
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
This solution ensures high intra-wafer and inter-wafer uniformity, prevents defects like metal corrosion and underpolish, and maintains optimal removal rates by dynamically adjusting the slurry composition during the polishing process, enhancing the overall CMP process efficiency and quality.
Implementation Method 1
an integrated slurry mixer-dispenser that continuously adjusts the slurry mixture ratio in real-time
Implementation Method 2
Chemical mechanical polishing processes are used to provide a planarization process during semiconductor manufacturing
Implementation Method 3
Chemical mechanical polishing (CMP) processes are used to provide a planarization process during semiconductor manufacturing
Data Source
AI summary
A chemical mechanical polishing (CMP) apparatus includes a polishing pad located on a top surface of a platen configured to rotate around a vertical axis passing through the platen, a wafer carrier configured to hold a substrate and facing the polishing pad, and an integrated slurry mixer-dispenser including at least two inlet ports configured to receive a respective slurry component, configured to generate slurry by mixing at least two slurry components provided through the at least two inlet ports, and including a dispensation port configured to dispense the slurry over the polishing pad.