Agitated Nutsche Filter Dryer — Fully Enclosed High-Purity Process Solution for Semiconductor Wet Electronic Chemicals

In the field of semiconductor wet electronic chemicals, where purity and consistency are paramount, the value of Wuxi Zhanghua's Agitated Nutsche Filter Dryer extends far beyond being merely a "vessel." Its core strength lies in successfully transplanting and elevating the pharmaceutical-grade sterile and enclosed design philosophy into the semiconductor-grade ultra-clean and precision-controlled environment, providing systematic process equipment assurance for ppb-level and even ppt-level metal ion control.

I. Fully Enclosed Process & Contamination Prevention Design: From "Reducing Contamination" to "Eliminating Contamination"

In semiconductor manufacturing, particles in cleanroom air and trace contaminants introduced by operators are major yield killers. The design philosophy of Zhanghua's ANFD is to eliminate all contamination pathways at the source:

· Elimination of Human Contact: From feeding to discharge, the entire process is completed within a closed vessel. Operators never come into contact with the material, completely eliminating the risk of particle and metal ion contamination introduced by manual handling in traditional open operations.

· Multi-Level Sealing Assurance: The main shaft is equipped with a double mechanical seal and a sealing liquid circulation system, ensuring that under long-term, high-load operation, there is absolutely no possibility of external air or lubricating oil penetrating the vessel.

· Dead-End-Free Design: The internal structure of the vessel is optimized with smooth transitions and no dead corners. Combined with the high-purity PFA lining, this fundamentally prevents material from remaining in dead corners where contamination could develop.

· Isolation from External Contamination: The fully enclosed design effectively isolates particulates, airborne contaminants, and microorganisms from the production environment, which is a fundamental prerequisite for manufacturing high-purity materials.

II. High-Purity PFA Lining: "Isolation" Replaces "Resistance" – Ensuring Purity at the Source

For the stringent requirement of metal ion < 10 ppb in semiconductor wet electronic chemical processes, traditional metallic materials (even stainless steel) are no longer adequate, as metal ions on their surfaces can still leach out under highly corrosive chemical environments. The key to solving this problem lies in "isolation" — completely separating the material from the metal substrate with an extremely pure, chemically inert layer. The ANFD lined with high-purity PFA (perfluoroalkoxy resin) is precisely designed for this purpose.

The application of PFA is not just about corrosion protection; it is a proactive purification measure:

· Ultra-Low Metal Ion Leaching: High-quality PFA linings can achieve metal ion leaching levels below 0.05 ppb. According to industrial information, good quality of PFA resin can obtain a metal ion leaching value less than 0.1 ppb; the current domestically made semiconductor grade ultra-pure PFA is capable of stably controlling the critical metal ion leaching in ppt level (part per trillion) and the overall metal ion leaching in ppb level. This material’s performance satisfies very strict certification requirements of semiconductor industry like SEMI F57 standard, in which the accelerated aging test by immersing ultrapure water at 85°C and establishes very strict requirement for metal ion leaching (e.g. Al ≤ 5 μg/m², Ca ≤ 15 μg/m², Fe ≤ 5 μg/m², etc.).

· No Particle Shedding:The PFA lining results in minimal particle emission as compared to glass-lined and other types of coatings in changing temperatures and mechanical vibration conditions that are necessary for high precision process control in 0.1 μm particles.

· Excellent Chemical Stability: PFA is resistant to practically all aggressive chemicals that are commonly employed in the fabrication process of semiconductors, such as HF, sulfuric acid, nitric acid, ammonia, hydrogen peroxide, and other organic solvents.

· Superior High-Temperature Stability and Cleanability: PFA has an extremely broad continuous range of operating temperatures (-254°C to 260°C) and can easily satisfy the temperature needs for the drying processes and others. PFA has a highly non-sticky surface, the roughness of which is controllable at less than 0.25 microns (Ra).

III. High-Efficiency Dynamic Displacement Washing: Precision "Chemical Purification" Process

The washing step is critical for removing metal ions already dissolved in the material. The advantage of Zhanghua's ANFD lies in transforming "washing" into a highly controllable purification process. By repeatedly injecting high-purity wash liquid into the closed vessel, combined with the gentle, uniform agitation of the S-type agitator blades, every batch of wash liquid is ensured to fully contact the material, efficiently "displacing" the metal-ion-containing mother liquor remaining in the filter cake or powder. The equipment supports multi-stage counter-current washing, achieving optimal ion removal with minimal high-purity solvent consumption, simultaneously optimizing water utilization and purification efficiency.

IV. High-Precision Filtration System: The Final Physical Barrier

Beyond chemical washing, physical filtration is equally indispensable. The equipment can be equipped with metal sintered mesh or PFA/PTFE filter media with precision ranging from 0.1 μm to 5 μm, effectively capturing trace solid particles, gels, and metal impurity particulates that may be present in the material. The filtration system is designed for easy cleaning and replacement, preventing secondary contamination caused by filter media shedding or degradation.

V. Comprehensive Cleanliness & Automation Support: Replacing "Human" Uncertainty with "Machine" Determinism

· CIP/SIP Systems: The equipment can also be equipped with Clean-In-Place (CIP) and Sterilize-In-Place (SIP), guaranteeing reliable results from batch to batch and meeting the most demanding standards for clean production.

· PLC/DCS Fully Automatic Control: The automated control system enables precise, stable replication of each process step, minimizing contamination risks from human intervention and achieving complete batch traceability.

VI. Broad Material & Process Compatibility

PFA coating can withstand almost all chemical attack by any aggressive chemicals that are normally employed for fabrication of semiconductors such as HF, sulfuric acid, nitric acid, ammonia, hydrogen peroxide, and many other organic solvents. In addition to this, wide temperature resistance range of the PFA coating (from -254° C to 260°C) also allows accommodating many different process temperatures, both low-temperature and high-temperature processes. 

VII. Customization & Engineering Service Capabilities

Semiconductor customer requirements are often highly customized. Zhanghua's advantage lies in providing not merely a standard equipment offering, but a complete engineering solution. Based on the specific crystal form, particle size, thermal sensitivity, and other parameters of the customer's material, we can customize the agitator design, filtration area, and drying profile. We can also provide complete process line equipment from upstream reactors to downstream automatic packaging, ensuring seamless, closed connections between all process steps.

VIII. Summary

For the demanding <10 ppb metal ion process, Wuxi Zhanghua's PFA-lined Agitated Nutsche Filter Dryer (anfd) offers a mature and reliable solution through the dual mechanism of physical isolation (PFA lining) + chemical displacement (dynamic washing). The core value of this solution lies in isolating metal contamination at the source, replacing manual intervention with precision control, and ensuring product consistency through a fully enclosed process — establishing it as the critical process equipment for ensuring electronic-grade purity in the post-treatment of high-purity materials including high-purity alumina, semiconductor precursors, electronic-grade metal powders, photoresists, and electronic specialty gas precursors.