Post-CMP Wafer Cleaning Spray Bar with Localized Nozzle Density
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Solution Overview
Problem
Current post-CMP wafer cleaning apparatuses are inefficient in removing slurry residues and result in a high defect count along the perimeter of the wafer surface.
Innovation Solution
A post-CMP wafer cleaning apparatus with a chamber, rollers to rotate the wafer, a brush for scrubbing, and a liquid spraying device with a denser nozzle arrangement near the annular peripheral area to provide increased liquid coverage and effective removal of slurry residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform nozzle arrangement is used on the spray bar, then the device complexity is reduced, but the cleaning efficiency deteriorates due to insufficient liquid coverage in the annular peripheral area
Solution Approach 1:
The spray bar is designed with non-uniform nozzle distribution where the spacing between adjacent nozzles varies along the length of the spray bar. Specifically, the spacing is smaller in the annular peripheral area compared to the central area, creating localized differences in liquid coverage density that match the specific cleaning needs of different wafer regions.
2Productivity
If a denser nozzle arrangement is used throughout the entire spray bar, then the cleaning efficiency in the annular peripheral area is improved, but the liquid consumption increases
Solution Approach 1:
The spray bar implements differential nozzle spacing where denser nozzle arrangements are localized only to the annular peripheral area that requires enhanced cleaning, while the central area maintains larger spacing. This ensures liquid is consumed efficiently only where needed rather than uniformly across the entire wafer surface.
3Productivity
If a denser nozzle arrangement is used near the annular peripheral area, then the cleaning efficiency in the peripheral area is improved, but the device complexity increases
Solution Approach 1:
The spray bar features a linear arrangement of nozzles with progressively varying spacing along its length, creating different liquid coverage densities in different radial zones of the wafer. This linear gradient approach achieves localized optimization without requiring complex multi-dimensional nozzle positioning or adjustable mechanisms.
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 apparatus effectively reduces the defect count by ensuring thorough cleaning of the wafer surface, particularly in the annular peripheral area, through targeted liquid distribution and scrubbing action.
Implementation Method 1
a spray bar adapted to spray a liquid on the wafer, wherein the spray bar comprises a first set of the nozzles, which is looser and is provided approximately in a middle section of the spray bar correspondent to the central area, and a second set of nozzles which is denser and is provided near two ends of the spray bar corresponding to the annular peripheral area
Implementation Method 2
A combination of rotational movement of the brush and force or pressure placed on the brush against the wafer causes the residual slurry to be removed from the surface of the wafer
Data Source
AI summary
A post-CMP wafer cleaning apparatus includes a chamber; a plurality of rollers adapted to hold and rotate a wafer within the chamber; at least one brush adapted to scrub a surface of the wafer to be cleaned; and a liquid spraying device adapted to spray a liquid on the wafer, the liquid spraying device comprising two spray bars jointed together via a joint member.