Temperature-Controlled CMP Apparatus for Uniform Planarization
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Solution Overview
Problem
Chemical mechanical polishing (CMP) in semiconductor fabrication leads to metal corrosion and uneven removal rates between dense and iso regions, causing topography differences and electrical failures due to excessive metal removal in iso regions.
Innovation Solution
A temperature-controlled CMP apparatus with a cooling system that monitors and controls the polishing surface temperature in real-time, reducing the removal rate in iso regions and mitigating metal corrosion by adjusting the coolant supply to maintain a temperature variation within 20%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP is used to planarize the wafer surface, then material removal is achieved, but uneven removal rates between dense and iso regions cause topography differences and metal corrosion
Solution Approach 1:
The patent changes the temperature parameter during CMP processing by introducing a cooling system that supplies coolant to the polishing pad. This temperature parameter change modifies the chemical reaction rates and material removal characteristics, enabling uniform removal across different region densities while preventing metal corrosion and dishing defects
Solution Approach 2:
The patent introduces coolant as an intermediary substance between the polishing pad and the wafer surface. The coolant mediates the thermal and chemical interactions during CMP, controlling the polishing environment to achieve uniform material removal and prevent harmful effects like metal corrosion
2Productivity
If higher polishing pressure is applied to increase removal rate, then productivity improves, but temperature increase accelerates metal corrosion in iso regions
Solution Approach 1:
The patent changes the temperature parameter by implementing active cooling during high-pressure polishing. This allows maintaining high removal rates through increased pressure while simultaneously controlling temperature to prevent metal corrosion that would otherwise be accelerated by the combined effect of pressure and heat
3Device complexity
If temperature is not controlled during CMP, then process simplicity is maintained, but temperature variation causes uneven removal rates and topography differences
Solution Approach 1:
The patent changes the temperature parameter control by adding a cooling system with coolant supply. This parameter control mechanism prevents temperature-induced variations in removal rates, achieving consistent polishing across different wafer regions while managing the increased system complexity
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 temperature-controlled CMP apparatus effectively reduces metal corrosion and dishing by maintaining a stable temperature, ensuring consistent removal rates across different feature densities, thereby preventing electrical failures.
Implementation Method 1
a cooling device coupled to the temperature controller and providing a coolant to the apparatus for CMP
Implementation Method 2
providing a coolant to reduce a temperature of the polishing surface
Data Source
AI summary
An apparatus for CMP includes a wafer carrier retaining a semiconductor wafer during a polishing operation, a slurry dispenser dispensing an abrasive slurry, and a temperature control system monitoring and controlling a temperature variation during the polishing operation. The temperature control system includes a temperature sensor detecting a temperature during the polishing operation and providing a signal corresponding to the temperature, a temperature controller coupled to the temperature sensor and receiving the signal from the temperature sensor, and a cooling device coupled to the temperature controller and providing a coolant to the apparatus for CMP.