CMP Polishing Surface Temperature Control for Throughput Stability
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Solution Overview
Problem
The CMP apparatus faces instability in throughput due to varying polishing times for wafers with different initial film thicknesses, making it challenging to achieve consistent processing times in a sequential polishing, cleaning, and drying process.
Innovation Solution
A polishing method and apparatus that regulate the temperature of the polishing surface using a heat exchanger to maintain a target polishing rate, calculated by determining the required temperature based on a relational expression correlating polishing rate and temperature, ensuring that the film thickness reaches the target thickness at a preset polishing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polishing is performed based on initial film thickness variations, then manufacturing precision is maintained, but productivity becomes unstable due to varying polishing times
Solution Approach 1:
The patent changes the physical parameter of polishing surface temperature to control and stabilize the polishing rate. By regulating temperature through a heat exchanger, the system maintains consistent polishing performance despite variations in initial film thickness, thereby stabilizing both precision and productivity
Solution Approach 2:
The system implements feedback control by measuring the actual polishing rate, comparing it with the target polishing rate, and adjusting the polishing surface temperature accordingly. This closed-loop control ensures that the polishing process maintains the target rate, stabilizing throughput while achieving precision
2Manufacturing precision
If polishing time is extended to accommodate thicker films, then manufacturing precision is achieved, but loss of time increases for thinner films
Solution Approach 1:
By changing the temperature parameter of the polishing surface, the system optimizes the polishing rate to match the target value. This allows the process to achieve precise thickness control without excessive polishing time, as the temperature is adjusted to maintain the optimal polishing rate throughout the process
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 allows for consistent termination of polishing at a preset time across multiple wafers, stabilizing throughput by adjusting the polishing rate in real-time to match the target polishing time, thereby maintaining process stability.
Implementation Method 1
regulating a temperature of the polishing surface by a heat exchanger
Data Source
AI summary
A polishing method capable of terminating polishing of a substrate, such as a wafer, at a preset polishing time is disclosed. The polishing method includes: polishing a substrate by pressing the substrate against a polishing surface of a polishing pad, while regulating a temperature of the polishing surface by a heat exchanger; calculating a target polishing rate required for an actual polishing time to coincide with a target polishing time, the actual polishing time being a time duration from start of polishing the substrate until a film thickness of the substrate reaches a target thickness; determining a target temperature of the polishing surface that can achieve the target polishing rate; and during polishing of the substrate, changing a temperature of the polishing surface to the target temperature by the heat exchanger.