The consistency, quality and cleanliness of the PVA material are essential
to the final performance of the product in a fabrication environment. ITW
Rippey has designed a state-of-the-art production facility to manufacture
the Symmetry™ product line in volume for the global semiconductor and
critical cleaning applications industries.
The entire manufacturing process is computer controlled and
monitored to ensure consistency of the final product on a volume production
scale. Under the guidance of our ISO certified system, all materials used
in the formulation and production of Symmetry PVA products are certified
and inspected to meet exacting specifications. The exclusive use of DI
water in the manufacturing of Symmetry™ products provides a high level of
purity and reduced potential for contamination. All Symmetry™ products are
then processed through ITW Rippey patented Microclean
system to achieve the industry's lowest overall levels of trace metals and
By investigating the link between the polymer structure and composition of
the resulting physical properties, ITW Rippey Corporation has designed an
optimized PVA brush roller to meet the future cleanliness requirements of
post-CMP and other critical cleaning process applications. Symmetry™ PVA
products are designed with increased crosslinking,
slightly higher density and compressive stress. These attributes lead to
increased brush lifetime and improved chemical compatibility without
sacrificing performance or the ability to clean without microscratching.
The higher molecular cross-linking exhibited by the Symmetry™ polymer
contributes to the enhanced strength and chemical compatibility. The
physical characteristics of the Symmetry™ PVA material allow for high
porosity without sacrificing the structural integrity or lifetime of the
brush. This high porosity results in improved flow-through performance and
better distribution of cleaning chemistries and reduces brush loading.
The final properties of the sponge brush roller can be
affected by a number of factors during the manufacturing process. These
factors include the molecular weight of the polymer, the degree of
hydrolysis of the raw PVA as well as the concentration of the reactants.
The degree of reaction, or acetalization
will dramatically affect the resulting properties of the material. This is
controlled by reaction times, temperature, reactant type and concentration.
With many factors influencing the resulting properties, tight controls of
the process are mandatory.
strength of ITW Rippey PVA material allows for a high porosity without
sacrificing structural integrity or brush lifetime
molecular cross-linking contributes to material strength and chemical
porosity increases brush flow-through performance:
distribution of cleaning chemistries
- Aids in
particle flushing and reduced brush loading
pore distribution throughout brush interior structure:
bulk physical properties leading to uniform cleaning across the
distribution of cleaning chemistry throughout the brush
The Proprietary Microclean Process
The Symmetry™ product line has the lowest verifiable results for trace
metals ensuring a high-purity material each and every time a new PVA brush
is installed onto your cleaning tool.
ITW Rippey Microclean Symmetry™ Cleanliness
trace metals as determined by nitric acid digestion and ICP/MS
leachable residue of any brush
extractable particle counts
Symmetry™ PVA Preservation Methodology
ammonium hydroxide preservation
- Does not
damage PVA by oxidation (hydrogen peroxide method) or free radical
formation (radiation methods)
with many commonly used cleaning chemistries
at low concentrations
removed by rinsing
ITW Rippey Corporation Patents
US 6,076,662 Packaged Sponge or Porous Polymeric Products.
6,120,616 Microcleaning Process for Sponge
or Porous Polymeric Product.
3. US 6,158,448 System for Cleaning Sponge or Porous Polymeric
6,176,067 Method for Packaging Sponge or Porous Polymeric Products.
5. US 6,182,323 Ultraclean Surface Treatment Device.