Semiconductor cleaning solution filtration, how to use Eaton filter bags to maintain the purity lifeline?

In semiconductor manufacturing, the pinnacle hall of modern industry, cleaning is a key auxiliary process throughout the entire process. The purity of the cleaning solution directly determines the cleanliness of the wafer surface, which in turn affects the yield and performance of the device. Any micron or even nanometer particles, metal ions or organic pollutants can cause circuit shorting, defects or reduced reliability. Therefore, choosing a filtration solution for the semiconductor cleaning line is a precise decision related to the "purity lifeline". Eaton filter bags, with its full-precision product line and special design for high-purity applications, are a reliable choice for many semiconductor factories. This article will delve into the semiconductor cleaning process scenarios and provide you with a detailed Eaton filter bag selection decision guide.

1. Strict requirements and core judgment elements for semiconductor cleaning and filtration
Different from ordinary industrial filtration, semiconductor cleaning and filtration must face three extreme challenges: ultra-high precision, absolute cleanliness, and chemical compatibility. Your selection decisions must be centered around the following elements:
1. Core indicators: particle removal accuracy and precipitate control.
- Accuracy requirements: Depending on the process nodes (such as 28nm, 14nm, and 7nm), the interception accuracy of particles in the cleaning solution can reach the nanometer level (such as 0.05μm, 0.1μm). You need to clarify the maximum particle size allowed by the process.
- Cleanliness standard: The filter bag itself cannot be a source of pollution. This means that leachable substances (metal ions, anions, total organic carbon TOC) and fiber shedding from filter materials must be strictly controlled. The level of extractables of the filter in ultrapure water is a key assessment indicator.
2. Usage requirements: Extreme working conditions and chemical compatibility.
- Fluid media: including ultrapure water (UPW), SC1 (ammonia + hydrogen peroxide), SC2 (hydrochloric acid + hydrogen peroxide), DHF (dilute hydrofluoric acid), organic solvents (such as IPA), etc., are diverse and highly corrosive.
- Temperature and pressure: Some high-temperature cleaning steps require long-term thermal stability of filter materials.
- Flow and pressure difference: The low pressure difference design at high flow rates helps save energy and stable operation, while ensuring filtration efficiency.
3. Budget scope: Total cost of ownership and cost of risk. In the semiconductor field, the initial filter bag cost is almost negligible in the face of the risk of scrapping entire batches of wafers due to pollution. Therefore, the core budget considerations for selection are "risk avoidance costs" and "comprehensive maintenance costs", pursuing absolute reliability and the longest online life to reduce the risk of process interruption and pollution caused by replacement.

2. In-depth analysis of Eaton's "arsenal" for semiconductor cleaning
Eaton provides targeted product lines for high-purity industries such as semiconductors. Before selecting models, you must understand their original design intentions:
1. ClearGaf™ series: This is the entry ticket and basic guarantee for entering the semiconductor field. Its core values lie in "cleanliness" and "safety".
- Full welding process: Welding rather than thread seam is used at the seam of the filter bag, which completely eliminates the risk of fiber shedding and leakage caused by the sutures, and meets the stringent requirements of no shedding objects.
- Excellent chemical compatibility: Select high-quality polypropylene (PP) and other materials, have good resistance to a variety of acids, bases, and solvents, and pass relevant extraction tests.
- Compliance endorsement: Compliance with FDA 21CFR and other food contact materials regulations, indirectly proving the safety and low-extraction characteristics of the materials. Suitable for UPW terminal polishing and partial chemical filtration with high requirements for cleanliness but relatively mild media.
2. High-precision (Accugaf™) series: When the cleaning process places higher requirements on particle interception accuracy, Accugaf™ is the main choice.
- Deep gradient filtration structure: Different from surface filtration, its multi-layered fine fiber structure can achieve deep capture, which not only has high accuracy (up to 0.5μm or even lower), but also has a larger pollution capacity, a longer life, and a slower pressure rise.
- Optimization for high purity: Materials and production environment are strictly controlled to reduce the introduction of impurities.
- Application scenarios: SC1/SC2 chemical liquid filtration, DHF filtration, high-precision solvent filtration and other key processes.
3. High Temperature and Strong Corrosion Resistance (Progaf™) series: For high-temperature and strong corrosive cleaning solutions such as hot sulfuric acid and phosphoric acid or special solvents. Made of PTFE membrane or specialty fibers, it provides top-level chemical and thermal stability and is the guardian under extreme working conditions.

Key choice dimensional comparison (semiconductor perspective):
| dimension | ClearGaf™ (Food and Pharmaceutical Grade) | Accugaf™ (High Precision) | Progaf™ (high temperature corrosion resistant) |
|----------------|----------------------------------|--------------------------------|----------------------------|
| core advantages | Absolutely clean, no fiber shedding, regulatory compliance| Ultra-high precision, deep filtration, long life | Extreme chemical/thermal stability |
| typical accuracy | 1-100 μm (focus on cleanliness) | 0.5-100 μm (focus on precision interception) | 1-500 μm (focus on stability) |
| Cleanliness guarantee | Full fusion welding, low extractables | Low dissolution design, clean production environment | Depending on the specific film/material grade |
| Main applicable media | UPW, Mild Chemicals | SC1, SC2, DHF, high purity solvent | Hot concentrated acid, special organic solvent |
| The primary driving force for selection| Control pollution sources and meet safety compliance | Achieve nanoscale particle interception | Responding to the most demanding chemical environments |

3. Decision-making road map for filter bag selection for semiconductor cleaning line
Following the following path will systematically reduce selection risks:
Step 1: Process mapping and requirements locking.
Draw a schematic diagram of your cleaning process flow to clarify each process using filtration: medium name, chemical composition, temperature, target filtration accuracy (based on process requirements or historical pollution data), current pain points (such as rapid rise in pressure difference, excessive particles, damaged filter bags, etc.). This is the cornerstone of all decision-making.
Step 2: Preliminary screening-product series positioning based on media and precision.
- For UPW and back-stage flushing water: Use ClearGaf™ series as the first choice and evaluate whether its accuracy meets the requirements.
- For wet chemicals such as SC1, SC2, and DHF: Give priority to the Accugaf™ series and select models based on the required accuracy. If the temperature is high or the concentration is special, check the compatibility table of the Progaf™ series simultaneously.
- For organic solvents such as IPA or special formulations: The chemical compatibility tables of each series need to be carefully checked. ClearGaf™ and Accugaf™ are usually candidates, and Progaf™ is considered in extreme cases.
Step 3: Deep diving-cleanliness and reliability verification.
This is the core part of semiconductor selection and cannot be determined solely by catalog parameters.
1. Request extract data: Ask Eaton to provide the metal ion, anion, and TOC dissolution test report of the target model in ultrapure water or similar media to compare your factory's internal control standards.
2. Focus on the value of Eaton SENTINEL® Seal Rings: In semiconductor applications, 100% leakage prevention means there is no risk of unfiltered fluid shorting, which is crucial to ensuring the consistency of the filtration effect of every drop of cleaning solution and avoiding random contamination incidents. Verify how the seal design matches your filter basket.
3. Life and differential pressure performance evaluation: Request reference data on differential pressure versus time curves under similar working conditions to evaluate its long-term operation stability and expected replacement cycle. The deep structure of Accugaf™ often excels in this regard.
Step 4: Small test and import decision-making.
On critical or new applications, pre-launch testing must be carried out.
- Sample testing: Conduct long-term operation testing on a side line or small flow device to monitor the number of particles, changes in metal ion concentration of the filtered liquid and the mechanical integrity of the filter bag itself.
- Cost decision-making: In the semiconductor field, the decision-making balance should be extremely tilted towards the "reliability" side. Calculate and compare the potential risk reduction in value (improved yield) and maintenance cost savings from reduced replacement frequency brought by different options, not just unit prices. The global unified high standard of production of Eaton products is itself a kind of risk mitigation.

4. Quick check of selection points for different cleaning scenarios
- UPW polishing mixed bed post/point-of-use: With extremely high cleaning requirements, low-extraction, high-precision ClearGaf™ or specially processed Accugaf™ are usually used, with accuracy often at 0.1μm or 0.05μm.
- Filtration before chemical delivery (CVD): Protect the distribution system and valves, select Accugaf™ or Progaf™ based on the nature of the chemical, and the accuracy needs to match process requirements.
- Slurry filtration after wafer brushing: Wear resistant design may be required, and high contamination tolerance is concerned. Models with Max-Load™ characteristics may be considered in an integrated manner.

Conclusion: Using deterministic filtering to deal with uncertain risks
Choosing Eaton filter bags for semiconductor cleaning essentially manages uncertain contamination risks in the process through deterministic filtration solutions. By strictly following the path of "process mapping → series positioning → cleanliness verification → test decision-making", you can maximize Eaton's advantages in material science, structural design and clean manufacturing to build a reliable line of defense for the purity of your cleaning solution. Eaton's full fusion welding process, SENTINEL® leak-proof seals, and special product lines for high-purity applications (such as ClearGaf™, Accugaf™) were created to meet the extreme requirements of the semiconductor industry. Remember that on this purity lifeline, the most expensive option is often not high-performance filter bags, but production losses due to filtration failures.