Substrate Cleaning Apparatus Radial Brush and Nozzle Motion
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Solution Overview
Problem
Conventional substrate cleaning methods using brushes often result in contamination transfer, especially when finer semiconductor device patterns are involved, leading to incomplete removal of particles on the wafer's rear surface, which can cause defects in subsequent lithography steps.
Innovation Solution
A substrate cleaning apparatus and method that employs a spin chuck, a brush, and a two-fluid nozzle, where the brush and nozzle move radially outward from the center of the substrate, with the nozzle positioned closer to the center than the brush, allowing liquid droplets to target areas previously contacted by the brush to remove contaminations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a brush is used for cleaning wafers multiple times, then cleaning coverage is improved, but brush contamination increases leading to wafer re-contamination
Solution Approach 1:
The cleaning process is segmented into two distinct stages: first the brush performs mechanical scrubbing, then the two-fluid nozzle performs liquid droplet spraying. This segmentation allows each component to perform its specialized function without interfering with the other, and the nozzle can clean areas the brush has contacted without the brush re-contaminating them.
Solution Approach 2:
The two-fluid nozzle acts as an intermediary cleaning mechanism that follows the brush. It uses liquid droplets sprayed at high speed to remove contaminations that the brush may have transferred to the wafer, serving as a secondary cleaning stage that ensures complete contamination removal.
2Object-generated harmful factors
If a brush contacts the wafer surface, then mechanical cleaning effectiveness is improved, but particle removal completeness deteriorates when patterns are finer
Solution Approach 1:
The invention merges two different cleaning mechanisms: mechanical brush scrubbing and two-fluid nozzle spraying. The brush provides mechanical cleaning force while the two-fluid nozzle delivers high-speed liquid droplets that can remove fine particles without mechanical contact, combining the advantages of both methods.
Solution Approach 2:
The two-fluid nozzle uses pneumatic and hydraulic principles to generate and spray liquid droplets at high speed onto the wafer surface. This non-contact or minimal-contact method is particularly effective for removing fine particles from areas with fine patterns where mechanical brushes might cause damage or re-contamination.
3Area of stationary object
If the brush moves radially outward to clean the wafer, then cleaning coverage is improved, but contamination transfer to the wafer increases
Solution Approach 1:
The two-fluid nozzle is positioned to spray liquid droplets onto the wafer surface before the brush contacts that area. This preliminary action pre-cleans the surface, reducing the likelihood that the brush will transfer contaminations to already-cleaned areas. The nozzle leads the brush radially outward, preparing the surface in advance.
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 effectively removes contaminations from the substrate even when the brush is contaminated, improving cleaning efficiency and preventing particle-related defects, especially during dry etching and lithography processes.
Implementation Method 1
a two-fluid nozzle that sprays liquid droplets onto the substrate
Implementation Method 2
a spin chuck that rotates a substrate
Implementation Method 3
a brush that comes into contact with the substrate to clean the same
Data Source
AI summary
In a substrate cleaning method and a substrate cleaning method according to the present invention, a brush 3 is brought into contact with a substrate W while rotating the same, and a cleaning position Sb of the brush 3 is moved relative to the substrate W from a center part of the substrate W toward a peripheral part thereof. A process fluid formed of liquid droplets and a gas is sprayed by a two-fluid nozzle 5 onto the substrate W, and a cleaning position Sn of the two-fluid nozzle 5 is moved relative to the substrate W from a center part of the substrate W toward a peripheral part thereof. During the movement of the cleaning position Sb of the brush 3 from the center part of the substrate W toward the peripheral part thereof, the cleaning position Sb of the two-fluid nozzle is positioned nearer to a center P0 than the cleaning position Sb of the brush 3. Since contaminations of the brush are prevented from adhering again to the wafer, it can be avoided that the wafer W is contaminated.