Chemical Mechanical Polishing Temperature Control
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes face challenges in maintaining high polishing rates due to excessive temperature increases at the polishing interface, which can be mitigated by controlling the surface temperature of the polishing pad, but this often requires a significant amount of polishing liquid, leading to inefficiencies.
Innovation Solution
A method that determines the optimal relationship between polishing liquid flow rate and polishing rate both with and without temperature control of the polishing pad, allowing for continuous supply of polishing liquid at reduced flow rates while maintaining surface temperature control to achieve high polishing rates, using a polishing slurry with ceria as abrasive grain and controlling the surface temperature between 42° C. to 46° C. for insulating films and 50° C. for copper films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large amount of polishing liquid is supplied to the polishing surface, then the polishing rate is maintained at a high level, but the amount of polishing liquid used increases significantly
Solution Approach 1:
The invention changes the temperature parameter of the polishing pad surface by introducing a temperature control mechanism. By maintaining the polishing pad surface temperature within a specific range (20°C to 40°C), the polishing liquid consumption is reduced while keeping the polishing rate high. The temperature control modifies the physical state and effectiveness of the polishing liquid, allowing lower flow rates to achieve the same polishing performance.
Solution Approach 2:
The invention implements a feedback control system that measures the actual polishing pad surface temperature and adjusts the cooling input accordingly. The temperature detecting means continuously monitors the temperature, and the controlling means modifies the cooling liquid flow or cooling power to maintain the temperature within the optimal range, thereby optimizing the balance between polishing rate and polishing liquid consumption.
2Productivity
If the surface temperature of the polishing pad is controlled to maintain high polishing rate, then the polishing rate is improved, but the amount of polishing liquid required increases
Solution Approach 1:
The invention changes the temperature parameter of the polishing pad surface by introducing a temperature control mechanism. By maintaining the polishing pad surface temperature within a specific range (20°C to 40°C), the polishing liquid consumption is reduced while keeping the polishing rate high. The temperature control modifies the physical state and effectiveness of the polishing liquid, allowing lower flow rates to achieve the same polishing performance.
3Loss of substance
If polishing liquid flow rate is reduced to decrease polishing liquid usage, then polishing liquid consumption is lowered, but the polishing rate decreases
Solution Approach 1:
The invention changes the temperature parameter of the polishing pad surface by introducing a temperature control mechanism. By maintaining the polishing pad surface temperature within a specific range (20°C to 40°C), the polishing liquid consumption is reduced while keeping the polishing rate high. The temperature control modifies the physical state and effectiveness of the polishing liquid, allowing lower flow rates to achieve the same polishing performance.
Solution Approach 2:
The invention implements a feedback control system that measures the actual polishing pad surface temperature and adjusts the cooling input accordingly. The temperature detecting means continuously monitors the temperature, and the controlling means modifies the cooling liquid flow or cooling power to maintain the temperature within the optimal range, thereby optimizing the balance between polishing rate and polishing liquid consumption.
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 approach reduces the amount of polishing liquid used without lowering the polishing rate, preventing issues like reduced uniformity and extreme reductions in polishing rate, by maintaining an appropriate polishing rate with controlled surface temperatures and reduced liquid flow rates, specifically between 20 ml/min and 200 ml/min.
Implementation Method 1
supplying a polishing liquid (slurry) to the polishing surface
Implementation Method 2
mainly deprive the surface of the polishing pad of vaporization heat
Implementation Method 3
eject a gas such as a cooling gas or the like from a gas ejecting portion such as a cooling nozzle or the like toward the surface of the polishing pad
Implementation Method 4
heat is generated by the friction between the substrate and the polishing pad
Data Source
AI summary
A polishing method for reducing an amount of polishing liquid used without lowering a polishing rate is provided. The polishing method comprises determining, in advance, the relationship between a supply flow rate of a polishing liquid and a polishing rate at the time the substrate is polished without controlling a surface temperature of the polishing pad, and the relationship between a supply flow rate of a polishing liquid and a polishing rate at the time the substrate is polished while controlling a surface temperature of the polishing pad at a predetermined level, and continuously supplying the polishing liquid to the surface of the polishing pad to achieve a higher polishing rate when the substrate is polished while controlling the surface temperature of the polishing pad at the predetermined level, than when the substrate is polished without controlling the surface temperature of the polishing pad.