Polishing Pad Temperature Control for Wafer Haze Reduction
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Solution Overview
Problem
Current methods for reducing haze in semiconductor wafer polishing, such as adjusting the temperature of the SC1 cleaning solution, compromise cleaning power and lead to frequent replacement of polishing pads, resulting in decreased productivity and increased costs due to insufficient control over haze levels.
Innovation Solution
A polishing method that involves deriving a correlation between the surface temperature of the polishing pad and the haze level, allowing for controlled surface temperature adjustments during polishing to minimize haze, thereby extending the service life of the polishing pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the temperature of SC1 cleaning solution is lowered to reduce haze, then the haze level decreases, but the cleaning power is reduced and particles cannot be sufficiently removed
Solution Approach 1:
The invention changes the temperature parameter of the polishing process itself (polishing pad temperature) rather than changing the cleaning solution temperature. By controlling the polishing pad surface temperature within a specific range (20-30°C), the invention achieves haze reduction while maintaining effective particle removal capability during the polishing operation.
2Manufacturing precision
If polishing conditions are adjusted to reduce haze, then haze control improves, but productivity decreases due to frequent polishing pad replacement
Solution Approach 1:
The invention implements feedback control by monitoring the polishing pad surface temperature and adjusting polishing conditions accordingly. This closed-loop control maintains optimal temperature conditions that prevent haze formation while preserving polishing pad performance, thereby extending pad service life and maintaining productivity.
Solution Approach 2:
The invention optimizes the polishing pad surface temperature parameter within a specific range (20-30°C) to achieve the dual benefit of haze reduction and polishing pad life extension. This parameter optimization prevents the degradation that would otherwise require frequent pad replacement.
3Manufacturing precision
If relative speeds of polishing pad and wafer are reduced to avoid haze, then some haze control is achieved, but haze cannot be fully controlled compared to cleaning condition adjustment
Solution Approach 1:
The invention identifies and controls the polishing pad surface temperature as the critical parameter for haze control, rather than relying on relative speed adjustment. By maintaining the polishing pad surface temperature within 20-30°C, the invention achieves superior and more reliable haze control compared to speed reduction methods.
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 method effectively controls haze levels, allowing the polishing pad to be used for a longer period while maintaining desired surface quality, reducing the need for frequent replacements and associated costs.
Implementation Method 1
polishing to polish a surface of a wafer by sliding the wafer held by a polishing head on a surface of a polishing pad while supplying a polishing slurry
Implementation Method 2
lowering the cleaning temperature of SC1, which is a mixed solution of NH3 and H2O2, suppresses the alkaline etching function on a wafer surface
Implementation Method 3
obtain a correlation between a surface temperature of the polishing pad and a haze level of a wafer polished with the use of the polishing pad in advance before performing the polishing, and also characterized in that the wafer is polished in the polishing while controlling the surface temperature of the polishing pad based on the correlation
Data Source
AI summary
A polishing method including polishing to polish a surface of a wafer by sliding the wafer held by a polishing head on a surface of a polishing pad while supplying a polishing slurry to the polishing pad attached to a turntable, the method including correlation derivation to obtain a correlation between a surface temperature of the polishing pad and a haze level of a wafer polished with the use of the polishing pad in advance before performing the polishing, and also the wafer is polished in the polishing while controlling the surface temperature of the polishing pad based on the correlation between the surface temperature of the polishing pad and the haze level of the wafer polished with the use of the polishing pad. Consequently, the polishing method can control a haze in polishing a wafer and thereby prolong the service life of the polishing pad.