ULPA Clean Bench for Semiconductor and Optics

What is the ULPA Clean Bench for Semiconductor and Optics?

A ULPA clean bench uses an ultra-low penetration air filter rated at 99.999 % efficiency to give ISO 4–5 conditions. It is selected for semiconductor, wafer, mask and precision optics handling where sub-micron particles matter.

Overview

The bench uses a U15 ULPA filter, tested to EN 1822 with at least 99.9995 % efficiency at the most penetrating particle size. Laminar flow is vertical or horizontal at 0.3–0.4 m/s, and the plenum is sealed with gel or gasket seals. Stainless steel 304 or 316 construction and anti-static powder coating reduce particle shedding. A differential pressure gauge monitors filter loading, and a variable-speed EC fan holds constant velocity as the filter loads. Particle counts at rest are typically below 3520 particles/m3 at 0.5 μm for ISO 5 or 352 for ISO 4 when well maintained. Units are supplied with low-noise fans and low-outgassing materials for wafer handling.

How does it work?

A cleanroom clean bench draws air from the room through a prefilter, pressurizes it in a plenum and forces it through a HEPA or ULPA filter so that unidirectional (laminar) air flows over the work surface at 0.3–0.5 m/s. In a horizontal design the air passes from the rear toward the operator, while in a vertical design it descends from the ceiling of the work zone. The moving air sweeps particles generated by operators and products away from the work area, maintaining ISO Class 5 (Class 100) air at the working height. Because the air exits into the room, these benches protect the product, not the operator. Stainless steel or powder-coated steel work surfaces, fluorescent LED lighting, and an airflow controller complete the unit. For cleanrooms, benches often use low-particle materials and sealed cable penetrations.

What are the key features?

• U15 ULPA filter tested to EN 1822
• Variable-speed EC fan with constant velocity control
• Gel or gasket sealed plenum
• Low-outgassing, low-shedding materials
• Differential pressure gauge for filter loading
• 304 or 316 stainless steel construction

What are the technical specifications?

A typical ulpa clean bench for semiconductor and optics configuration offers filter grade of U15 ULPA, ≥ 99.9995 %, cleanliness class of ISO 4–5, air velocity of 0.3–0.4 m/s, airflow direction of Vertical or horizontal, work-zone width of 900–1500 mm and fan type of EC, variable speed. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The ULPA Clean Bench for Semiconductor and Optics is used in wafer handling, photomask inspection, precision optics assembly and MEMS device packaging. Across the wider Clean Benches class, laboratories also deploy it for electronics assembly, optical component inspection and medical-device assembly.

Which standards and certifications apply?

Relevant standards and methods include ISO 14644-1 (cleanroom classification), ISO 14644-3 (test methods), ISO 14644-4 (design and construction), IEST-RP-CC002 (unidirectional flow devices), JG/T 292 (clean bench), GB/T 25915.1 and EN 1822 (HEPA and ULPA filters). Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Place the bench away from doors and supply diffusers, since room drafts above 0.1 m/s can disturb the laminar flow. Commission with a filter leak test, airflow velocity survey and particle count to ISO 14644-3. Replace prefilters every 3–6 months and HEPA filters when face velocity cannot be restored at maximum fan speed, typically every 3–5 years. Wipe surfaces with isopropanol or a compatible disinfectant, working from clean to dirty. Because benches recirculate room air, they must not be used with hazardous chemicals, pathogens or cytotoxics. Record airflow and particle checks in the cleanroom log for regulatory audits.

How do I select the right ULPA Clean Bench for Semiconductor and Optics?

Choose ULPA when sub-micron particles affect yield or quality and ISO 4–5 conditions are needed. It costs more and has higher pressure drop than HEPA. RFQ: filter class, particle limits, EC fan, material restrictions and ESD.

How does it compare with other Clean Benches variants?

Choose by the direction of airflow, the size of the work area and the product being handled. Vertical flow suits assembly of components where operators work over the product, while horizontal flow suits inspection of larger items. Check the work-zone width, commonly 900–1800 mm, the filter grade, H14 HEPA or ULPA U15 for critical semiconductor work, and the air velocity control. Consider noise, which should remain under 65 dB(A), vibration, and ESD-safe surfaces for electronics. Stainless steel tops suit pharmaceutical use, while ESD-rated tops suit electronics. Decide whether a mobile stand, a wall-hung option or built-in lighting is required. Benches for chemicals or biologicals require fume or biosafety protection instead, not a clean bench.