Paul Industries designs and builds cleanrooms and controlled environments for Oregon’s semiconductor and advanced manufacturing sector. A fab cleanroom and a pharmaceutical cleanroom share a name and very little else. The particles are an order of magnitude smaller, the contaminants that matter most are not particles at all, and the floor has to be still enough that a lithography tool can resolve features measured in nanometres. Applying pharmaceutical cleanroom practice to a fab produces a room that certifies and cannot make product.
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Three separate problems that happen to share a room
Oregon’s semiconductor cluster is the state’s largest manufacturing sector, employing roughly 33,000 people, with Hillsboro hosting Intel’s largest and most comprehensive site worldwide for research and manufacturing. The environments those operations require are controlled along three axes at once, and only one of them appears in a cleanliness classification.
Particles. The classification axis, and the one people think of. Fab core areas run at the strictest ISO classes, achieved through unidirectional airflow over the critical area rather than through dilution. The practical difference from a pharmaceutical room is that filtration coverage approaches the whole ceiling rather than a fraction of it, and air is returned through the floor and recirculated continuously.
Airborne molecular contamination. This is the axis with no equivalent in pharmaceutical work and it is the one that most often surprises. Gas-phase contaminants, acids, bases, condensables and dopants, are molecular. They pass straight through a particle filter, because a particle filter is not a chemical filter. They react with wafer surfaces, they haze optics, and at the relevant process nodes the tolerable concentrations are extremely low.
Controlling them requires chemical filtration in the air path, selected for the specific contaminant class, plus materials discipline throughout the room, because construction materials, sealants, floor finishes and even some cleanroom consumables outgas. A room built with the wrong sealant can contaminate itself for months. That makes material selection a process requirement rather than a finishes decision, and it is exactly the decision most likely to be made by someone optimizing cost.
Vibration. Lithography and metrology tools resolve features far below the amplitude of ordinary building vibration, so the floor has to be exceptionally stable. This is structural engineering rather than cleanroom engineering: mass, stiffness, isolated slabs, and keeping rotating equipment away from the tools it would otherwise disturb. It is also almost impossible to fix afterwards, which puts it firmly in the category of things that must be right in the first design.
| Aspect | Pharmaceutical | Semiconductor fab |
|---|---|---|
| Primary contaminant | Viable and non-viable particles | Particles at much smaller sizes, plus molecular species |
| Air pattern | Unidirectional over critical zones only | Near full ceiling coverage with floor return |
| Chemical filtration | Rarely required | Routinely required and specified by contaminant class |
| Vibration | Rarely a design driver | Frequently the governing structural requirement |
| Materials | Chosen for cleanability and disinfectant compatibility | Chosen additionally for outgassing behavior |
| Humidity and temperature | Comfort and product stability bands | Very tight, for dimensional and electrostatic reasons |
What that costs to run, and where the money goes
| Continuous load | Per year | Over ten years |
|---|---|---|
| 100 kW | $70,518 | $705,180 |
| 200 kW | $141,036 | $1,410,360 |
| 400 kW | $282,072 | $2,820,720 |
Two observations about those numbers, both of which cut against common assumptions.
First, Oregon industrial electricity averages 8.05 cents per kilowatt-hour, essentially at the 8.13 cent national average (EIA, 2024) and above neighbouring Washington, despite the region’s hydroelectric reputation. A fab’s environmental systems run continuously at large loads, so that difference compounds into serious money, and it is worth working from the actual tariff rather than a regional assumption.
Second, the dominant cost is fan power, and fan power is driven by pressure drop and by the volume of air moved. That makes two design decisions unusually valuable: low pressure drop throughout the air path, which is cheap at design stage and impossible later; and the tightest temperature and humidity band the process genuinely requires rather than the tightest anyone can imagine. Unnecessarily narrow control bands are paid for continuously, and they are frequently inherited from a specification nobody has revisited.
Building it, and the details that decide the outcome
Airflow return path. Floor return demands a raised floor with the free area the airflow actually needs, and equipment installed later can block it. Designing generous return capacity and keeping it clear is more important than it sounds, because blocked return shows up as poor airflow uniformity at the tools rather than as an obvious fault.
Penetrations and sealing. Every service entering the room is a leak path and a potential contamination source. Sealed properly at construction, with materials chosen for outgassing as well as for sealing, and detailed so a future service can be added without cutting through the work.
Electrostatic control. Static damages devices directly and attracts particles to surfaces. Flooring, humidity control and grounding are part of the environmental specification rather than an electrical afterthought.
Gowning and transitions. People are the largest particle source in any cleanroom, and a fab’s tolerance is lower. Gowning areas sized and sequenced so the correct procedure is also the natural one, with airlocks and pressure cascade that survive real traffic volumes.
We handle room construction, air handling and filtration including chemical filtration integration, raised floor and return systems, utility penetrations and sealing, and the qualification package: classification to ISO 14644-1, recovery testing, filter integrity, airflow uniformity and visualization, and pressure cascade verification. ISO 14644-2 governs the ongoing monitoring plan.
Standards referenced: ISO 14644-1 · EIA electricity price data · ISO 14644-2 · ASME BPE
Frequently asked questions
Do you build cleanrooms for Oregon semiconductor plants?
Yes, across Hillsboro, Portland, Beaverton, Corvallis, Gresham and statewide: room construction, air handling and filtration including chemical filtration, raised floor and return systems, utility penetrations, and the full qualification package to ISO 14644-1 and ISO 14644-2.
How is a fab cleanroom different from a pharmaceutical one?
The particles that matter are much smaller, molecular contamination matters as much or more, vibration is frequently the governing structural requirement, and temperature and humidity bands are far tighter. Applying pharmaceutical practice produces a room that certifies and cannot make product.
What is airborne molecular contamination?
Gas-phase contaminants including acids, bases, condensables and dopants. They are molecular, so they pass straight through particle filters, which are not chemical filters. They react with wafer surfaces and haze optics, and at current process nodes the tolerable concentrations are extremely low.
How is molecular contamination controlled?
Chemical filtration in the air path, selected for the specific contaminant class, combined with materials discipline throughout the room. Construction materials, sealants, floor finishes and some consumables outgas, so a room built with the wrong sealant can contaminate itself for months.
Why does vibration matter so much?
Because lithography and metrology tools resolve features far below the amplitude of ordinary building vibration. Control comes from mass, stiffness, isolated slabs and keeping rotating equipment away from sensitive tools. It is structural engineering, and it is nearly impossible to correct after the building exists.
Where does the running cost go?
Overwhelmingly into fan power, which is driven by pressure drop and by the volume of air moved. That makes low pressure drop design and realistic temperature and humidity bands the two highest-value decisions, and both are cheap at design stage and expensive or impossible afterwards.
Should we specify the tightest possible control bands?
Only as tight as the process genuinely requires. Unnecessarily narrow temperature and humidity bands are paid for continuously in energy, and they are frequently inherited from a specification nobody has revisited against the actual tools in the room.
Is Oregon power cheap for a fab?
Less than the region’s reputation suggests. Oregon industrial electricity averages 8.05 cents per kilowatt-hour, essentially at the 8.13 cent national average and above neighbouring Washington (EIA, 2024). On continuously running environmental systems that difference compounds, so work from the actual tariff.
What is most often compromised during construction?
Materials selection, because outgassing behavior is invisible and cost pressure is not. Sealants, floor finishes and construction materials chosen on price can contaminate a room molecularly for months after handover, and that decision is usually made by someone with no visibility of the process consequence.
How do I get a quote for an Oregon fab cleanroom?
Use the form on this page or call 201-450-8280. Useful inputs are the class required and the tools to be installed, the vibration criterion if one has been set, temperature and humidity requirements, whether chemical filtration is specified and for which contaminants, and the building’s existing structure.
What air change rates and airflow patterns do fab cleanrooms use?
Fabs use unidirectional downflow through ceiling filters over the whole process area or over minienvironments around the tools, with raised floors returning air, at velocities and rates far above pharmaceutical practice. Ballroom fabs move enormous volumes; minienvironment designs concentrate the cleanest air where it matters.
What are minienvironments and how do they change the design?
Enclosures around tools or wafer handling that hold the highest cleanliness locally, so the surrounding room can be a lower class. They reduce air handling energy substantially and change the room from a ballroom into a controlled space around enclosed tools.
How is the gas-phase filtration in a fab specified?
By the contaminant classes the process is sensitive to, such as acids, bases, condensables and dopants, with chemical filter media chosen for each and a replacement schedule set by loading rather than by the calendar. Media that has saturated passes the contaminant through with no visible sign.
Where do construction materials contribute to molecular contamination?
Through outgassing of sealants, adhesives, paints, flooring and gasket materials, which release volatile organics and amines for months after installation, and through cleaning chemicals used during construction and turnover. Material selection and outgassing testing are part of a fab cleanroom specification for that reason.
How is vibration specified and confirmed for a fab floor?
As a velocity or acceleration criterion from the tool suppliers' requirements, designed for with structural stiffness and mass and isolation from vibration sources, and confirmed by site measurement before and after tool installation. A floor that meets the criterion empty may fail it once pumps and air handling run.
How is the sub-fab used?
The sub-fab houses pumps, abatement, chemical delivery and utilities beneath the cleanroom, connected to the tools above, so that vibration, contamination and maintenance stay out of the cleanroom. Its design affects the cleanroom's vibration and its contamination as much as the room itself.
What electrostatic controls do fabs need?
Humidity control, ionisation, grounded flooring and equipment, and materials chosen for charge behaviour, because static attracts particles to wafers and damages devices. Ionisation in the airflow is standard in wafer handling areas.
What construction protocol keeps a fab cleanroom clean during build-out?
A staged cleanliness protocol that tightens as construction proceeds, with dust-generating work finished before finishes go in, controlled entry and clean-build practices for the final stages, and cleaning and verification before the room is sealed. A room that is built clean qualifies quickly; one that is cleaned afterward never quite reaches the same baseline.
How is temperature stability achieved?
With tight control of supply air, thermal mass in the structure and control loops tuned for stability rather than speed. Lithography needs stability measured in fractions of a degree, and the control system is designed for that rather than for an average.
Does Oregon's climate help a fab?
Cool, moist marine air allows free cooling for a large part of the year and reduces humidification demand, both of which cut energy. Outside air also carries molecular contaminants that the chemical filtration has to handle.
What water and utilities does a fab cleanroom depend on?
Ultrapure water, high-purity gases, specialty chemicals and process cooling water, delivered from the sub-fab with the purity and reliability the tools need. The cleanroom is the visible part; the utilities underneath are the larger investment.
How is a fab cleanroom certified?
By particle counts at defined locations and occupancy states, airflow velocity and uniformity, pressure, temperature and humidity, vibration surveys, molecular contamination sampling and electrostatic checks. Certification is a set of surveys rather than one test.
Can an existing fab be expanded without stopping?
Yes, with strict separation between the construction area and the operating fab: sealed partitions, separate air handling for the work area, and protocols for every opening. It is done routinely and it depends entirely on discipline at the boundary.
What about smaller semiconductor equipment and photonics rooms in Oregon?
They follow the same principles at lower intensity, with the priorities set by the process: vibration for optics, molecular contamination for some coatings, particles for assembly. The design is scaled to the actual sensitivity.
What is the commonest problem you see in Oregon fab-type rooms?
Molecular contamination from materials chosen for cleanliness on a particle basis alone. The room certifies on particle counts and the process suffers from outgassing that nobody measured.
Building next to a fab that is still running
Most cleanroom work in an established cluster is not a greenfield fab. It is an extension, a tool install, a reconfiguration or a new bay adjacent to production that cannot stop. That constraint changes the job more than the specification does.
The governing risk is that construction generates exactly what the neighbouring room exists to exclude: particles from cutting and drilling, molecular contamination from adhesives, sealants and coatings, and vibration from almost everything. All three travel, and the shared systems are how they travel.
Separate the air before anything else. The construction zone needs its own air handling, held at negative pressure relative to production, exhausting outside rather than into a shared return. Where the two spaces share a plenum or a return path, that path has to be physically blocked, not merely balanced against, because a pressure relationship holds only while everything is working and a physical barrier holds regardless.
Treat molecular contamination as the harder problem. Particles are visible, well understood and readily controlled by containment. Outgassing from a curing epoxy floor or a fresh sealant is invisible, travels with the air, and can affect a neighbouring room for weeks. Material selection for the construction phase deserves the same scrutiny as material selection for the finished room, and low-outgassing alternatives are worth their premium when the alternative is disrupting production.
Schedule vibration against production. Core drilling, demolition and anything percussive should be planned around the tools that cannot tolerate it, which means the schedule has to be built with production rather than presented to it. Continuous vibration monitoring during the noisy phases, with agreed limits and a stop trigger, converts an argument into a measurement.
Control people and materials as one flow. The construction crew, their tools and their materials all cross the boundary repeatedly. A defined route, a defined transition, and materials unpacked outside rather than inside remove most of the risk, and they work only if the compliant route is also the practical one.
Agree the reopening criteria up front. Before work starts, everyone should know what measurements will demonstrate that the extended space is ready and that the neighbouring space was unaffected. Deciding that at the end, under schedule pressure, is how a room gets released on optimism.
Building or upgrading an Oregon cleanroom?
Tell us the tools going in and whether a vibration criterion has been set. Those two shape the building long before the air handling does. Call 201-450-8280 or use the form below.