The manufacturing of PVA brush rollers is a complex process that requires stringent process controls to create a consistent and reliable final product. As the pioneer in the use of PVA for critical cleaning applications in the high technology industry, ITW Rippey is uniquely positioned to design and manufacture a technically advanced new level of PVA products for the most demanding process applications.

Symmetry™ Material Technology
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 leachable residues.

Symmetry™ Material Physical Properties
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.

• The strength of ITW Rippey PVA material allows for a high porosity without sacrificing structural integrity or brush lifetime
• Higher molecular cross-linking contributes to material strength and chemical compatibility
• High porosity increases brush flow-through performance:
  • Better distribution of cleaning chemistries
  • Aids in particle flushing and reduced brush loading
• Consistent pore distribution throughout brush interior structure:
  • Consistent bulk physical properties leading to uniform cleaning across the substrate
  • Even 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

• Lowest trace metals as determined by nitric acid digestion and ICP/MS analysis
• Lowest leachable residue of any brush
• Lowest extractable particle counts
• Patented process

Symmetry™ PVA Preservation Methodology

• Patented ammonium hydroxide preservation
• Does not damage PVA by oxidation (hydrogen peroxide method) or free radical formation (radiation methods)
• Compatible with many commonly used cleaning chemistries
• Effective at low concentrations
• Easily removed by rinsing
  
  ITW Rippey Corporation Patents
  1. US 6,076,662 Packaged Sponge or Porous Polymeric Products.
  2. US 6,120,616 Microcleaning Process for Sponge or Porous Polymeric Product.
  3. US 6,158,448 System for Cleaning Sponge or Porous Polymeric Products.
  4. US 6,176,067 Method for Packaging Sponge or Porous Polymeric Products.
  5. US 6,182,323 Ultraclean Surface Treatment Device.